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Diffstat (limited to 'clang/lib/Sema/SemaChecking.cpp')
| -rw-r--r-- | clang/lib/Sema/SemaChecking.cpp | 5153 |
1 files changed, 5153 insertions, 0 deletions
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp new file mode 100644 index 0000000..0d15ce2 --- /dev/null +++ b/clang/lib/Sema/SemaChecking.cpp @@ -0,0 +1,5153 @@ +//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements extra semantic analysis beyond what is enforced +// by the C type system. +// +//===----------------------------------------------------------------------===// + +#include "clang/Sema/Initialization.h" +#include "clang/Sema/Sema.h" +#include "clang/Sema/SemaInternal.h" +#include "clang/Sema/Initialization.h" +#include "clang/Sema/ScopeInfo.h" +#include "clang/Analysis/Analyses/FormatString.h" +#include "clang/AST/ASTContext.h" +#include "clang/AST/CharUnits.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/DeclObjC.h" +#include "clang/AST/ExprCXX.h" +#include "clang/AST/ExprObjC.h" +#include "clang/AST/EvaluatedExprVisitor.h" +#include "clang/AST/DeclObjC.h" +#include "clang/AST/StmtCXX.h" +#include "clang/AST/StmtObjC.h" +#include "clang/Lex/Preprocessor.h" +#include "llvm/ADT/BitVector.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/Support/raw_ostream.h" +#include "clang/Basic/TargetBuiltins.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/Basic/ConvertUTF.h" +#include <limits> +using namespace clang; +using namespace sema; + +SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, + unsigned ByteNo) const { + return SL->getLocationOfByte(ByteNo, PP.getSourceManager(), + PP.getLangOpts(), PP.getTargetInfo()); +} + +/// Checks that a call expression's argument count is the desired number. +/// This is useful when doing custom type-checking. Returns true on error. +static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) { + unsigned argCount = call->getNumArgs(); + if (argCount == desiredArgCount) return false; + + if (argCount < desiredArgCount) + return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args) + << 0 /*function call*/ << desiredArgCount << argCount + << call->getSourceRange(); + + // Highlight all the excess arguments. + SourceRange range(call->getArg(desiredArgCount)->getLocStart(), + call->getArg(argCount - 1)->getLocEnd()); + + return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args) + << 0 /*function call*/ << desiredArgCount << argCount + << call->getArg(1)->getSourceRange(); +} + +/// CheckBuiltinAnnotationString - Checks that string argument to the builtin +/// annotation is a non wide string literal. +static bool CheckBuiltinAnnotationString(Sema &S, Expr *Arg) { + Arg = Arg->IgnoreParenCasts(); + StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); + if (!Literal || !Literal->isAscii()) { + S.Diag(Arg->getLocStart(), diag::err_builtin_annotation_not_string_constant) + << Arg->getSourceRange(); + return true; + } + return false; +} + +ExprResult +Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { + ExprResult TheCallResult(Owned(TheCall)); + + // Find out if any arguments are required to be integer constant expressions. + unsigned ICEArguments = 0; + ASTContext::GetBuiltinTypeError Error; + Context.GetBuiltinType(BuiltinID, Error, &ICEArguments); + if (Error != ASTContext::GE_None) + ICEArguments = 0; // Don't diagnose previously diagnosed errors. + + // If any arguments are required to be ICE's, check and diagnose. + for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) { + // Skip arguments not required to be ICE's. + if ((ICEArguments & (1 << ArgNo)) == 0) continue; + + llvm::APSInt Result; + if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) + return true; + ICEArguments &= ~(1 << ArgNo); + } + + switch (BuiltinID) { + case Builtin::BI__builtin___CFStringMakeConstantString: + assert(TheCall->getNumArgs() == 1 && + "Wrong # arguments to builtin CFStringMakeConstantString"); + if (CheckObjCString(TheCall->getArg(0))) + return ExprError(); + break; + case Builtin::BI__builtin_stdarg_start: + case Builtin::BI__builtin_va_start: + if (SemaBuiltinVAStart(TheCall)) + return ExprError(); + break; + case Builtin::BI__builtin_isgreater: + case Builtin::BI__builtin_isgreaterequal: + case Builtin::BI__builtin_isless: + case Builtin::BI__builtin_islessequal: + case Builtin::BI__builtin_islessgreater: + case Builtin::BI__builtin_isunordered: + if (SemaBuiltinUnorderedCompare(TheCall)) + return ExprError(); + break; + case Builtin::BI__builtin_fpclassify: + if (SemaBuiltinFPClassification(TheCall, 6)) + return ExprError(); + break; + case Builtin::BI__builtin_isfinite: + case Builtin::BI__builtin_isinf: + case Builtin::BI__builtin_isinf_sign: + case Builtin::BI__builtin_isnan: + case Builtin::BI__builtin_isnormal: + if (SemaBuiltinFPClassification(TheCall, 1)) + return ExprError(); + break; + case Builtin::BI__builtin_shufflevector: + return SemaBuiltinShuffleVector(TheCall); + // TheCall will be freed by the smart pointer here, but that's fine, since + // SemaBuiltinShuffleVector guts it, but then doesn't release it. + case Builtin::BI__builtin_prefetch: + if (SemaBuiltinPrefetch(TheCall)) + return ExprError(); + break; + case Builtin::BI__builtin_object_size: + if (SemaBuiltinObjectSize(TheCall)) + return ExprError(); + break; + case Builtin::BI__builtin_longjmp: + if (SemaBuiltinLongjmp(TheCall)) + return ExprError(); + break; + + case Builtin::BI__builtin_classify_type: + if (checkArgCount(*this, TheCall, 1)) return true; + TheCall->setType(Context.IntTy); + break; + case Builtin::BI__builtin_constant_p: + if (checkArgCount(*this, TheCall, 1)) return true; + TheCall->setType(Context.IntTy); + break; + case Builtin::BI__sync_fetch_and_add: + case Builtin::BI__sync_fetch_and_add_1: + case Builtin::BI__sync_fetch_and_add_2: + case Builtin::BI__sync_fetch_and_add_4: + case Builtin::BI__sync_fetch_and_add_8: + case Builtin::BI__sync_fetch_and_add_16: + case Builtin::BI__sync_fetch_and_sub: + case Builtin::BI__sync_fetch_and_sub_1: + case Builtin::BI__sync_fetch_and_sub_2: + case Builtin::BI__sync_fetch_and_sub_4: + case Builtin::BI__sync_fetch_and_sub_8: + case Builtin::BI__sync_fetch_and_sub_16: + case Builtin::BI__sync_fetch_and_or: + case Builtin::BI__sync_fetch_and_or_1: + case Builtin::BI__sync_fetch_and_or_2: + case Builtin::BI__sync_fetch_and_or_4: + case Builtin::BI__sync_fetch_and_or_8: + case Builtin::BI__sync_fetch_and_or_16: + case Builtin::BI__sync_fetch_and_and: + case Builtin::BI__sync_fetch_and_and_1: + case Builtin::BI__sync_fetch_and_and_2: + case Builtin::BI__sync_fetch_and_and_4: + case Builtin::BI__sync_fetch_and_and_8: + case Builtin::BI__sync_fetch_and_and_16: + case Builtin::BI__sync_fetch_and_xor: + case Builtin::BI__sync_fetch_and_xor_1: + case Builtin::BI__sync_fetch_and_xor_2: + case Builtin::BI__sync_fetch_and_xor_4: + case Builtin::BI__sync_fetch_and_xor_8: + case Builtin::BI__sync_fetch_and_xor_16: + case Builtin::BI__sync_add_and_fetch: + case Builtin::BI__sync_add_and_fetch_1: + case Builtin::BI__sync_add_and_fetch_2: + case Builtin::BI__sync_add_and_fetch_4: + case Builtin::BI__sync_add_and_fetch_8: + case Builtin::BI__sync_add_and_fetch_16: + case Builtin::BI__sync_sub_and_fetch: + case Builtin::BI__sync_sub_and_fetch_1: + case Builtin::BI__sync_sub_and_fetch_2: + case Builtin::BI__sync_sub_and_fetch_4: + case Builtin::BI__sync_sub_and_fetch_8: + case Builtin::BI__sync_sub_and_fetch_16: + case Builtin::BI__sync_and_and_fetch: + case Builtin::BI__sync_and_and_fetch_1: + case Builtin::BI__sync_and_and_fetch_2: + case Builtin::BI__sync_and_and_fetch_4: + case Builtin::BI__sync_and_and_fetch_8: + case Builtin::BI__sync_and_and_fetch_16: + case Builtin::BI__sync_or_and_fetch: + case Builtin::BI__sync_or_and_fetch_1: + case Builtin::BI__sync_or_and_fetch_2: + case Builtin::BI__sync_or_and_fetch_4: + case Builtin::BI__sync_or_and_fetch_8: + case Builtin::BI__sync_or_and_fetch_16: + case Builtin::BI__sync_xor_and_fetch: + case Builtin::BI__sync_xor_and_fetch_1: + case Builtin::BI__sync_xor_and_fetch_2: + case Builtin::BI__sync_xor_and_fetch_4: + case Builtin::BI__sync_xor_and_fetch_8: + case Builtin::BI__sync_xor_and_fetch_16: + case Builtin::BI__sync_val_compare_and_swap: + case Builtin::BI__sync_val_compare_and_swap_1: + case Builtin::BI__sync_val_compare_and_swap_2: + case Builtin::BI__sync_val_compare_and_swap_4: + case Builtin::BI__sync_val_compare_and_swap_8: + case Builtin::BI__sync_val_compare_and_swap_16: + case Builtin::BI__sync_bool_compare_and_swap: + case Builtin::BI__sync_bool_compare_and_swap_1: + case Builtin::BI__sync_bool_compare_and_swap_2: + case Builtin::BI__sync_bool_compare_and_swap_4: + case Builtin::BI__sync_bool_compare_and_swap_8: + case Builtin::BI__sync_bool_compare_and_swap_16: + case Builtin::BI__sync_lock_test_and_set: + case Builtin::BI__sync_lock_test_and_set_1: + case Builtin::BI__sync_lock_test_and_set_2: + case Builtin::BI__sync_lock_test_and_set_4: + case Builtin::BI__sync_lock_test_and_set_8: + case Builtin::BI__sync_lock_test_and_set_16: + case Builtin::BI__sync_lock_release: + case Builtin::BI__sync_lock_release_1: + case Builtin::BI__sync_lock_release_2: + case Builtin::BI__sync_lock_release_4: + case Builtin::BI__sync_lock_release_8: + case Builtin::BI__sync_lock_release_16: + case Builtin::BI__sync_swap: + case Builtin::BI__sync_swap_1: + case Builtin::BI__sync_swap_2: + case Builtin::BI__sync_swap_4: + case Builtin::BI__sync_swap_8: + case Builtin::BI__sync_swap_16: + return SemaBuiltinAtomicOverloaded(move(TheCallResult)); +#define BUILTIN(ID, TYPE, ATTRS) +#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \ + case Builtin::BI##ID: \ + return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::AO##ID); +#include "clang/Basic/Builtins.def" + case Builtin::BI__builtin_annotation: + if (CheckBuiltinAnnotationString(*this, TheCall->getArg(1))) + return ExprError(); + break; + } + + // Since the target specific builtins for each arch overlap, only check those + // of the arch we are compiling for. + if (BuiltinID >= Builtin::FirstTSBuiltin) { + switch (Context.getTargetInfo().getTriple().getArch()) { + case llvm::Triple::arm: + case llvm::Triple::thumb: + if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) + return ExprError(); + break; + default: + break; + } + } + + return move(TheCallResult); +} + +// Get the valid immediate range for the specified NEON type code. +static unsigned RFT(unsigned t, bool shift = false) { + NeonTypeFlags Type(t); + int IsQuad = Type.isQuad(); + switch (Type.getEltType()) { + case NeonTypeFlags::Int8: + case NeonTypeFlags::Poly8: + return shift ? 7 : (8 << IsQuad) - 1; + case NeonTypeFlags::Int16: + case NeonTypeFlags::Poly16: + return shift ? 15 : (4 << IsQuad) - 1; + case NeonTypeFlags::Int32: + return shift ? 31 : (2 << IsQuad) - 1; + case NeonTypeFlags::Int64: + return shift ? 63 : (1 << IsQuad) - 1; + case NeonTypeFlags::Float16: + assert(!shift && "cannot shift float types!"); + return (4 << IsQuad) - 1; + case NeonTypeFlags::Float32: + assert(!shift && "cannot shift float types!"); + return (2 << IsQuad) - 1; + } + llvm_unreachable("Invalid NeonTypeFlag!"); +} + +/// getNeonEltType - Return the QualType corresponding to the elements of +/// the vector type specified by the NeonTypeFlags. This is used to check +/// the pointer arguments for Neon load/store intrinsics. +static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) { + switch (Flags.getEltType()) { + case NeonTypeFlags::Int8: + return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy; + case NeonTypeFlags::Int16: + return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy; + case NeonTypeFlags::Int32: + return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy; + case NeonTypeFlags::Int64: + return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy; + case NeonTypeFlags::Poly8: + return Context.SignedCharTy; + case NeonTypeFlags::Poly16: + return Context.ShortTy; + case NeonTypeFlags::Float16: + return Context.UnsignedShortTy; + case NeonTypeFlags::Float32: + return Context.FloatTy; + } + llvm_unreachable("Invalid NeonTypeFlag!"); +} + +bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { + llvm::APSInt Result; + + unsigned mask = 0; + unsigned TV = 0; + int PtrArgNum = -1; + bool HasConstPtr = false; + switch (BuiltinID) { +#define GET_NEON_OVERLOAD_CHECK +#include "clang/Basic/arm_neon.inc" +#undef GET_NEON_OVERLOAD_CHECK + } + + // For NEON intrinsics which are overloaded on vector element type, validate + // the immediate which specifies which variant to emit. + unsigned ImmArg = TheCall->getNumArgs()-1; + if (mask) { + if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) + return true; + + TV = Result.getLimitedValue(64); + if ((TV > 63) || (mask & (1 << TV)) == 0) + return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) + << TheCall->getArg(ImmArg)->getSourceRange(); + } + + if (PtrArgNum >= 0) { + // Check that pointer arguments have the specified type. + Expr *Arg = TheCall->getArg(PtrArgNum); + if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) + Arg = ICE->getSubExpr(); + ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); + QualType RHSTy = RHS.get()->getType(); + QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context); + if (HasConstPtr) + EltTy = EltTy.withConst(); + QualType LHSTy = Context.getPointerType(EltTy); + AssignConvertType ConvTy; + ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); + if (RHS.isInvalid()) + return true; + if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, + RHS.get(), AA_Assigning)) + return true; + } + + // For NEON intrinsics which take an immediate value as part of the + // instruction, range check them here. + unsigned i = 0, l = 0, u = 0; + switch (BuiltinID) { + default: return false; + case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; + case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; + case ARM::BI__builtin_arm_vcvtr_f: + case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; +#define GET_NEON_IMMEDIATE_CHECK +#include "clang/Basic/arm_neon.inc" +#undef GET_NEON_IMMEDIATE_CHECK + }; + + // Check that the immediate argument is actually a constant. + if (SemaBuiltinConstantArg(TheCall, i, Result)) + return true; + + // Range check against the upper/lower values for this isntruction. + unsigned Val = Result.getZExtValue(); + if (Val < l || Val > (u + l)) + return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) + << l << u+l << TheCall->getArg(i)->getSourceRange(); + + // FIXME: VFP Intrinsics should error if VFP not present. + return false; +} + +/// CheckFunctionCall - Check a direct function call for various correctness +/// and safety properties not strictly enforced by the C type system. +bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) { + // Get the IdentifierInfo* for the called function. + IdentifierInfo *FnInfo = FDecl->getIdentifier(); + + // None of the checks below are needed for functions that don't have + // simple names (e.g., C++ conversion functions). + if (!FnInfo) + return false; + + // FIXME: This mechanism should be abstracted to be less fragile and + // more efficient. For example, just map function ids to custom + // handlers. + + // Printf and scanf checking. + for (specific_attr_iterator<FormatAttr> + i = FDecl->specific_attr_begin<FormatAttr>(), + e = FDecl->specific_attr_end<FormatAttr>(); i != e ; ++i) { + CheckFormatArguments(*i, TheCall); + } + + for (specific_attr_iterator<NonNullAttr> + i = FDecl->specific_attr_begin<NonNullAttr>(), + e = FDecl->specific_attr_end<NonNullAttr>(); i != e; ++i) { + CheckNonNullArguments(*i, TheCall->getArgs(), + TheCall->getCallee()->getLocStart()); + } + + unsigned CMId = FDecl->getMemoryFunctionKind(); + if (CMId == 0) + return false; + + // Handle memory setting and copying functions. + if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) + CheckStrlcpycatArguments(TheCall, FnInfo); + else if (CMId == Builtin::BIstrncat) + CheckStrncatArguments(TheCall, FnInfo); + else + CheckMemaccessArguments(TheCall, CMId, FnInfo); + + return false; +} + +bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, + Expr **Args, unsigned NumArgs) { + for (specific_attr_iterator<FormatAttr> + i = Method->specific_attr_begin<FormatAttr>(), + e = Method->specific_attr_end<FormatAttr>(); i != e ; ++i) { + + CheckFormatArguments(*i, Args, NumArgs, false, lbrac, + Method->getSourceRange()); + } + + // diagnose nonnull arguments. + for (specific_attr_iterator<NonNullAttr> + i = Method->specific_attr_begin<NonNullAttr>(), + e = Method->specific_attr_end<NonNullAttr>(); i != e; ++i) { + CheckNonNullArguments(*i, Args, lbrac); + } + + return false; +} + +bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) { + const VarDecl *V = dyn_cast<VarDecl>(NDecl); + if (!V) + return false; + + QualType Ty = V->getType(); + if (!Ty->isBlockPointerType()) + return false; + + // format string checking. + for (specific_attr_iterator<FormatAttr> + i = NDecl->specific_attr_begin<FormatAttr>(), + e = NDecl->specific_attr_end<FormatAttr>(); i != e ; ++i) { + CheckFormatArguments(*i, TheCall); + } + + return false; +} + +ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, + AtomicExpr::AtomicOp Op) { + CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); + DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); + + // All these operations take one of the following forms: + enum { + // C __c11_atomic_init(A *, C) + Init, + // C __c11_atomic_load(A *, int) + Load, + // void __atomic_load(A *, CP, int) + Copy, + // C __c11_atomic_add(A *, M, int) + Arithmetic, + // C __atomic_exchange_n(A *, CP, int) + Xchg, + // void __atomic_exchange(A *, C *, CP, int) + GNUXchg, + // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) + C11CmpXchg, + // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) + GNUCmpXchg + } Form = Init; + const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; + const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; + // where: + // C is an appropriate type, + // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, + // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, + // M is C if C is an integer, and ptrdiff_t if C is a pointer, and + // the int parameters are for orderings. + + assert(AtomicExpr::AO__c11_atomic_init == 0 && + AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load + && "need to update code for modified C11 atomics"); + bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && + Op <= AtomicExpr::AO__c11_atomic_fetch_xor; + bool IsN = Op == AtomicExpr::AO__atomic_load_n || + Op == AtomicExpr::AO__atomic_store_n || + Op == AtomicExpr::AO__atomic_exchange_n || + Op == AtomicExpr::AO__atomic_compare_exchange_n; + bool IsAddSub = false; + + switch (Op) { + case AtomicExpr::AO__c11_atomic_init: + Form = Init; + break; + + case AtomicExpr::AO__c11_atomic_load: + case AtomicExpr::AO__atomic_load_n: + Form = Load; + break; + + case AtomicExpr::AO__c11_atomic_store: + case AtomicExpr::AO__atomic_load: + case AtomicExpr::AO__atomic_store: + case AtomicExpr::AO__atomic_store_n: + Form = Copy; + break; + + case AtomicExpr::AO__c11_atomic_fetch_add: + case AtomicExpr::AO__c11_atomic_fetch_sub: + case AtomicExpr::AO__atomic_fetch_add: + case AtomicExpr::AO__atomic_fetch_sub: + case AtomicExpr::AO__atomic_add_fetch: + case AtomicExpr::AO__atomic_sub_fetch: + IsAddSub = true; + // Fall through. + case AtomicExpr::AO__c11_atomic_fetch_and: + case AtomicExpr::AO__c11_atomic_fetch_or: + case AtomicExpr::AO__c11_atomic_fetch_xor: + case AtomicExpr::AO__atomic_fetch_and: + case AtomicExpr::AO__atomic_fetch_or: + case AtomicExpr::AO__atomic_fetch_xor: + case AtomicExpr::AO__atomic_fetch_nand: + case AtomicExpr::AO__atomic_and_fetch: + case AtomicExpr::AO__atomic_or_fetch: + case AtomicExpr::AO__atomic_xor_fetch: + case AtomicExpr::AO__atomic_nand_fetch: + Form = Arithmetic; + break; + + case AtomicExpr::AO__c11_atomic_exchange: + case AtomicExpr::AO__atomic_exchange_n: + Form = Xchg; + break; + + case AtomicExpr::AO__atomic_exchange: + Form = GNUXchg; + break; + + case AtomicExpr::AO__c11_atomic_compare_exchange_strong: + case AtomicExpr::AO__c11_atomic_compare_exchange_weak: + Form = C11CmpXchg; + break; + + case AtomicExpr::AO__atomic_compare_exchange: + case AtomicExpr::AO__atomic_compare_exchange_n: + Form = GNUCmpXchg; + break; + } + + // Check we have the right number of arguments. + if (TheCall->getNumArgs() < NumArgs[Form]) { + Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) + << 0 << NumArgs[Form] << TheCall->getNumArgs() + << TheCall->getCallee()->getSourceRange(); + return ExprError(); + } else if (TheCall->getNumArgs() > NumArgs[Form]) { + Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), + diag::err_typecheck_call_too_many_args) + << 0 << NumArgs[Form] << TheCall->getNumArgs() + << TheCall->getCallee()->getSourceRange(); + return ExprError(); + } + + // Inspect the first argument of the atomic operation. + Expr *Ptr = TheCall->getArg(0); + Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); + const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); + if (!pointerType) { + Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) + << Ptr->getType() << Ptr->getSourceRange(); + return ExprError(); + } + + // For a __c11 builtin, this should be a pointer to an _Atomic type. + QualType AtomTy = pointerType->getPointeeType(); // 'A' + QualType ValType = AtomTy; // 'C' + if (IsC11) { + if (!AtomTy->isAtomicType()) { + Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) + << Ptr->getType() << Ptr->getSourceRange(); + return ExprError(); + } + ValType = AtomTy->getAs<AtomicType>()->getValueType(); + } + + // For an arithmetic operation, the implied arithmetic must be well-formed. + if (Form == Arithmetic) { + // gcc does not enforce these rules for GNU atomics, but we do so for sanity. + if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { + Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) + << IsC11 << Ptr->getType() << Ptr->getSourceRange(); + return ExprError(); + } + if (!IsAddSub && !ValType->isIntegerType()) { + Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) + << IsC11 << Ptr->getType() << Ptr->getSourceRange(); + return ExprError(); + } + } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { + // For __atomic_*_n operations, the value type must be a scalar integral or + // pointer type which is 1, 2, 4, 8 or 16 bytes in length. + Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) + << IsC11 << Ptr->getType() << Ptr->getSourceRange(); + return ExprError(); + } + + if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) { + // For GNU atomics, require a trivially-copyable type. This is not part of + // the GNU atomics specification, but we enforce it for sanity. + Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) + << Ptr->getType() << Ptr->getSourceRange(); + return ExprError(); + } + + // FIXME: For any builtin other than a load, the ValType must not be + // const-qualified. + + switch (ValType.getObjCLifetime()) { + case Qualifiers::OCL_None: + case Qualifiers::OCL_ExplicitNone: + // okay + break; + + case Qualifiers::OCL_Weak: + case Qualifiers::OCL_Strong: + case Qualifiers::OCL_Autoreleasing: + // FIXME: Can this happen? By this point, ValType should be known + // to be trivially copyable. + Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) + << ValType << Ptr->getSourceRange(); + return ExprError(); + } + + QualType ResultType = ValType; + if (Form == Copy || Form == GNUXchg || Form == Init) + ResultType = Context.VoidTy; + else if (Form == C11CmpXchg || Form == GNUCmpXchg) + ResultType = Context.BoolTy; + + // The type of a parameter passed 'by value'. In the GNU atomics, such + // arguments are actually passed as pointers. + QualType ByValType = ValType; // 'CP' + if (!IsC11 && !IsN) + ByValType = Ptr->getType(); + + // The first argument --- the pointer --- has a fixed type; we + // deduce the types of the rest of the arguments accordingly. Walk + // the remaining arguments, converting them to the deduced value type. + for (unsigned i = 1; i != NumArgs[Form]; ++i) { + QualType Ty; + if (i < NumVals[Form] + 1) { + switch (i) { + case 1: + // The second argument is the non-atomic operand. For arithmetic, this + // is always passed by value, and for a compare_exchange it is always + // passed by address. For the rest, GNU uses by-address and C11 uses + // by-value. + assert(Form != Load); + if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) + Ty = ValType; + else if (Form == Copy || Form == Xchg) + Ty = ByValType; + else if (Form == Arithmetic) + Ty = Context.getPointerDiffType(); + else + Ty = Context.getPointerType(ValType.getUnqualifiedType()); + break; + case 2: + // The third argument to compare_exchange / GNU exchange is a + // (pointer to a) desired value. + Ty = ByValType; + break; + case 3: + // The fourth argument to GNU compare_exchange is a 'weak' flag. + Ty = Context.BoolTy; + break; + } + } else { + // The order(s) are always converted to int. + Ty = Context.IntTy; + } + + InitializedEntity Entity = + InitializedEntity::InitializeParameter(Context, Ty, false); + ExprResult Arg = TheCall->getArg(i); + Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); + if (Arg.isInvalid()) + return true; + TheCall->setArg(i, Arg.get()); + } + + // Permute the arguments into a 'consistent' order. + SmallVector<Expr*, 5> SubExprs; + SubExprs.push_back(Ptr); + switch (Form) { + case Init: + // Note, AtomicExpr::getVal1() has a special case for this atomic. + SubExprs.push_back(TheCall->getArg(1)); // Val1 + break; + case Load: + SubExprs.push_back(TheCall->getArg(1)); // Order + break; + case Copy: + case Arithmetic: + case Xchg: + SubExprs.push_back(TheCall->getArg(2)); // Order + SubExprs.push_back(TheCall->getArg(1)); // Val1 + break; + case GNUXchg: + // Note, AtomicExpr::getVal2() has a special case for this atomic. + SubExprs.push_back(TheCall->getArg(3)); // Order + SubExprs.push_back(TheCall->getArg(1)); // Val1 + SubExprs.push_back(TheCall->getArg(2)); // Val2 + break; + case C11CmpXchg: + SubExprs.push_back(TheCall->getArg(3)); // Order + SubExprs.push_back(TheCall->getArg(1)); // Val1 + SubExprs.push_back(TheCall->getArg(4)); // OrderFail + SubExprs.push_back(TheCall->getArg(2)); // Val2 + break; + case GNUCmpXchg: + SubExprs.push_back(TheCall->getArg(4)); // Order + SubExprs.push_back(TheCall->getArg(1)); // Val1 + SubExprs.push_back(TheCall->getArg(5)); // OrderFail + SubExprs.push_back(TheCall->getArg(2)); // Val2 + SubExprs.push_back(TheCall->getArg(3)); // Weak + break; + } + + return Owned(new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), + SubExprs.data(), SubExprs.size(), + ResultType, Op, + TheCall->getRParenLoc())); +} + + +/// checkBuiltinArgument - Given a call to a builtin function, perform +/// normal type-checking on the given argument, updating the call in +/// place. This is useful when a builtin function requires custom +/// type-checking for some of its arguments but not necessarily all of +/// them. +/// +/// Returns true on error. +static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { + FunctionDecl *Fn = E->getDirectCallee(); + assert(Fn && "builtin call without direct callee!"); + + ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); + InitializedEntity Entity = + InitializedEntity::InitializeParameter(S.Context, Param); + + ExprResult Arg = E->getArg(0); + Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); + if (Arg.isInvalid()) + return true; + + E->setArg(ArgIndex, Arg.take()); + return false; +} + +/// SemaBuiltinAtomicOverloaded - We have a call to a function like +/// __sync_fetch_and_add, which is an overloaded function based on the pointer +/// type of its first argument. The main ActOnCallExpr routines have already +/// promoted the types of arguments because all of these calls are prototyped as +/// void(...). +/// +/// This function goes through and does final semantic checking for these +/// builtins, +ExprResult +Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { + CallExpr *TheCall = (CallExpr *)TheCallResult.get(); + DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); + FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); + + // Ensure that we have at least one argument to do type inference from. + if (TheCall->getNumArgs() < 1) { + Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) + << 0 << 1 << TheCall->getNumArgs() + << TheCall->getCallee()->getSourceRange(); + return ExprError(); + } + + // Inspect the first argument of the atomic builtin. This should always be + // a pointer type, whose element is an integral scalar or pointer type. + // Because it is a pointer type, we don't have to worry about any implicit + // casts here. + // FIXME: We don't allow floating point scalars as input. + Expr *FirstArg = TheCall->getArg(0); + ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); + if (FirstArgResult.isInvalid()) + return ExprError(); + FirstArg = FirstArgResult.take(); + TheCall->setArg(0, FirstArg); + + const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); + if (!pointerType) { + Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) + << FirstArg->getType() << FirstArg->getSourceRange(); + return ExprError(); + } + + QualType ValType = pointerType->getPointeeType(); + if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && + !ValType->isBlockPointerType()) { + Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) + << FirstArg->getType() << FirstArg->getSourceRange(); + return ExprError(); + } + + switch (ValType.getObjCLifetime()) { + case Qualifiers::OCL_None: + case Qualifiers::OCL_ExplicitNone: + // okay + break; + + case Qualifiers::OCL_Weak: + case Qualifiers::OCL_Strong: + case Qualifiers::OCL_Autoreleasing: + Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) + << ValType << FirstArg->getSourceRange(); + return ExprError(); + } + + // Strip any qualifiers off ValType. + ValType = ValType.getUnqualifiedType(); + + // The majority of builtins return a value, but a few have special return + // types, so allow them to override appropriately below. + QualType ResultType = ValType; + + // We need to figure out which concrete builtin this maps onto. For example, + // __sync_fetch_and_add with a 2 byte object turns into + // __sync_fetch_and_add_2. +#define BUILTIN_ROW(x) \ + { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ + Builtin::BI##x##_8, Builtin::BI##x##_16 } + + static const unsigned BuiltinIndices[][5] = { + BUILTIN_ROW(__sync_fetch_and_add), + BUILTIN_ROW(__sync_fetch_and_sub), + BUILTIN_ROW(__sync_fetch_and_or), + BUILTIN_ROW(__sync_fetch_and_and), + BUILTIN_ROW(__sync_fetch_and_xor), + + BUILTIN_ROW(__sync_add_and_fetch), + BUILTIN_ROW(__sync_sub_and_fetch), + BUILTIN_ROW(__sync_and_and_fetch), + BUILTIN_ROW(__sync_or_and_fetch), + BUILTIN_ROW(__sync_xor_and_fetch), + + BUILTIN_ROW(__sync_val_compare_and_swap), + BUILTIN_ROW(__sync_bool_compare_and_swap), + BUILTIN_ROW(__sync_lock_test_and_set), + BUILTIN_ROW(__sync_lock_release), + BUILTIN_ROW(__sync_swap) + }; +#undef BUILTIN_ROW + + // Determine the index of the size. + unsigned SizeIndex; + switch (Context.getTypeSizeInChars(ValType).getQuantity()) { + case 1: SizeIndex = 0; break; + case 2: SizeIndex = 1; break; + case 4: SizeIndex = 2; break; + case 8: SizeIndex = 3; break; + case 16: SizeIndex = 4; break; + default: + Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) + << FirstArg->getType() << FirstArg->getSourceRange(); + return ExprError(); + } + + // Each of these builtins has one pointer argument, followed by some number of + // values (0, 1 or 2) followed by a potentially empty varags list of stuff + // that we ignore. Find out which row of BuiltinIndices to read from as well + // as the number of fixed args. + unsigned BuiltinID = FDecl->getBuiltinID(); + unsigned BuiltinIndex, NumFixed = 1; + switch (BuiltinID) { + default: llvm_unreachable("Unknown overloaded atomic builtin!"); + case Builtin::BI__sync_fetch_and_add: + case Builtin::BI__sync_fetch_and_add_1: + case Builtin::BI__sync_fetch_and_add_2: + case Builtin::BI__sync_fetch_and_add_4: + case Builtin::BI__sync_fetch_and_add_8: + case Builtin::BI__sync_fetch_and_add_16: + BuiltinIndex = 0; + break; + + case Builtin::BI__sync_fetch_and_sub: + case Builtin::BI__sync_fetch_and_sub_1: + case Builtin::BI__sync_fetch_and_sub_2: + case Builtin::BI__sync_fetch_and_sub_4: + case Builtin::BI__sync_fetch_and_sub_8: + case Builtin::BI__sync_fetch_and_sub_16: + BuiltinIndex = 1; + break; + + case Builtin::BI__sync_fetch_and_or: + case Builtin::BI__sync_fetch_and_or_1: + case Builtin::BI__sync_fetch_and_or_2: + case Builtin::BI__sync_fetch_and_or_4: + case Builtin::BI__sync_fetch_and_or_8: + case Builtin::BI__sync_fetch_and_or_16: + BuiltinIndex = 2; + break; + + case Builtin::BI__sync_fetch_and_and: + case Builtin::BI__sync_fetch_and_and_1: + case Builtin::BI__sync_fetch_and_and_2: + case Builtin::BI__sync_fetch_and_and_4: + case Builtin::BI__sync_fetch_and_and_8: + case Builtin::BI__sync_fetch_and_and_16: + BuiltinIndex = 3; + break; + + case Builtin::BI__sync_fetch_and_xor: + case Builtin::BI__sync_fetch_and_xor_1: + case Builtin::BI__sync_fetch_and_xor_2: + case Builtin::BI__sync_fetch_and_xor_4: + case Builtin::BI__sync_fetch_and_xor_8: + case Builtin::BI__sync_fetch_and_xor_16: + BuiltinIndex = 4; + break; + + case Builtin::BI__sync_add_and_fetch: + case Builtin::BI__sync_add_and_fetch_1: + case Builtin::BI__sync_add_and_fetch_2: + case Builtin::BI__sync_add_and_fetch_4: + case Builtin::BI__sync_add_and_fetch_8: + case Builtin::BI__sync_add_and_fetch_16: + BuiltinIndex = 5; + break; + + case Builtin::BI__sync_sub_and_fetch: + case Builtin::BI__sync_sub_and_fetch_1: + case Builtin::BI__sync_sub_and_fetch_2: + case Builtin::BI__sync_sub_and_fetch_4: + case Builtin::BI__sync_sub_and_fetch_8: + case Builtin::BI__sync_sub_and_fetch_16: + BuiltinIndex = 6; + break; + + case Builtin::BI__sync_and_and_fetch: + case Builtin::BI__sync_and_and_fetch_1: + case Builtin::BI__sync_and_and_fetch_2: + case Builtin::BI__sync_and_and_fetch_4: + case Builtin::BI__sync_and_and_fetch_8: + case Builtin::BI__sync_and_and_fetch_16: + BuiltinIndex = 7; + break; + + case Builtin::BI__sync_or_and_fetch: + case Builtin::BI__sync_or_and_fetch_1: + case Builtin::BI__sync_or_and_fetch_2: + case Builtin::BI__sync_or_and_fetch_4: + case Builtin::BI__sync_or_and_fetch_8: + case Builtin::BI__sync_or_and_fetch_16: + BuiltinIndex = 8; + break; + + case Builtin::BI__sync_xor_and_fetch: + case Builtin::BI__sync_xor_and_fetch_1: + case Builtin::BI__sync_xor_and_fetch_2: + case Builtin::BI__sync_xor_and_fetch_4: + case Builtin::BI__sync_xor_and_fetch_8: + case Builtin::BI__sync_xor_and_fetch_16: + BuiltinIndex = 9; + break; + + case Builtin::BI__sync_val_compare_and_swap: + case Builtin::BI__sync_val_compare_and_swap_1: + case Builtin::BI__sync_val_compare_and_swap_2: + case Builtin::BI__sync_val_compare_and_swap_4: + case Builtin::BI__sync_val_compare_and_swap_8: + case Builtin::BI__sync_val_compare_and_swap_16: + BuiltinIndex = 10; + NumFixed = 2; + break; + + case Builtin::BI__sync_bool_compare_and_swap: + case Builtin::BI__sync_bool_compare_and_swap_1: + case Builtin::BI__sync_bool_compare_and_swap_2: + case Builtin::BI__sync_bool_compare_and_swap_4: + case Builtin::BI__sync_bool_compare_and_swap_8: + case Builtin::BI__sync_bool_compare_and_swap_16: + BuiltinIndex = 11; + NumFixed = 2; + ResultType = Context.BoolTy; + break; + + case Builtin::BI__sync_lock_test_and_set: + case Builtin::BI__sync_lock_test_and_set_1: + case Builtin::BI__sync_lock_test_and_set_2: + case Builtin::BI__sync_lock_test_and_set_4: + case Builtin::BI__sync_lock_test_and_set_8: + case Builtin::BI__sync_lock_test_and_set_16: + BuiltinIndex = 12; + break; + + case Builtin::BI__sync_lock_release: + case Builtin::BI__sync_lock_release_1: + case Builtin::BI__sync_lock_release_2: + case Builtin::BI__sync_lock_release_4: + case Builtin::BI__sync_lock_release_8: + case Builtin::BI__sync_lock_release_16: + BuiltinIndex = 13; + NumFixed = 0; + ResultType = Context.VoidTy; + break; + + case Builtin::BI__sync_swap: + case Builtin::BI__sync_swap_1: + case Builtin::BI__sync_swap_2: + case Builtin::BI__sync_swap_4: + case Builtin::BI__sync_swap_8: + case Builtin::BI__sync_swap_16: + BuiltinIndex = 14; + break; + } + + // Now that we know how many fixed arguments we expect, first check that we + // have at least that many. + if (TheCall->getNumArgs() < 1+NumFixed) { + Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) + << 0 << 1+NumFixed << TheCall->getNumArgs() + << TheCall->getCallee()->getSourceRange(); + return ExprError(); + } + + // Get the decl for the concrete builtin from this, we can tell what the + // concrete integer type we should convert to is. + unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; + const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); + IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName); + FunctionDecl *NewBuiltinDecl = + cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID, + TUScope, false, DRE->getLocStart())); + + // The first argument --- the pointer --- has a fixed type; we + // deduce the types of the rest of the arguments accordingly. Walk + // the remaining arguments, converting them to the deduced value type. + for (unsigned i = 0; i != NumFixed; ++i) { + ExprResult Arg = TheCall->getArg(i+1); + + // GCC does an implicit conversion to the pointer or integer ValType. This + // can fail in some cases (1i -> int**), check for this error case now. + // Initialize the argument. + InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, + ValType, /*consume*/ false); + Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); + if (Arg.isInvalid()) + return ExprError(); + + // Okay, we have something that *can* be converted to the right type. Check + // to see if there is a potentially weird extension going on here. This can + // happen when you do an atomic operation on something like an char* and + // pass in 42. The 42 gets converted to char. This is even more strange + // for things like 45.123 -> char, etc. + // FIXME: Do this check. + TheCall->setArg(i+1, Arg.take()); + } + + ASTContext& Context = this->getASTContext(); + + // Create a new DeclRefExpr to refer to the new decl. + DeclRefExpr* NewDRE = DeclRefExpr::Create( + Context, + DRE->getQualifierLoc(), + SourceLocation(), + NewBuiltinDecl, + /*enclosing*/ false, + DRE->getLocation(), + NewBuiltinDecl->getType(), + DRE->getValueKind()); + + // Set the callee in the CallExpr. + // FIXME: This leaks the original parens and implicit casts. + ExprResult PromotedCall = UsualUnaryConversions(NewDRE); + if (PromotedCall.isInvalid()) + return ExprError(); + TheCall->setCallee(PromotedCall.take()); + + // Change the result type of the call to match the original value type. This + // is arbitrary, but the codegen for these builtins ins design to handle it + // gracefully. + TheCall->setType(ResultType); + + return move(TheCallResult); +} + +/// CheckObjCString - Checks that the argument to the builtin +/// CFString constructor is correct +/// Note: It might also make sense to do the UTF-16 conversion here (would +/// simplify the backend). +bool Sema::CheckObjCString(Expr *Arg) { + Arg = Arg->IgnoreParenCasts(); + StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); + + if (!Literal || !Literal->isAscii()) { + Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) + << Arg->getSourceRange(); + return true; + } + + if (Literal->containsNonAsciiOrNull()) { + StringRef String = Literal->getString(); + unsigned NumBytes = String.size(); + SmallVector<UTF16, 128> ToBuf(NumBytes); + const UTF8 *FromPtr = (UTF8 *)String.data(); + UTF16 *ToPtr = &ToBuf[0]; + + ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, + &ToPtr, ToPtr + NumBytes, + strictConversion); + // Check for conversion failure. + if (Result != conversionOK) + Diag(Arg->getLocStart(), + diag::warn_cfstring_truncated) << Arg->getSourceRange(); + } + return false; +} + +/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. +/// Emit an error and return true on failure, return false on success. +bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { + Expr *Fn = TheCall->getCallee(); + if (TheCall->getNumArgs() > 2) { + Diag(TheCall->getArg(2)->getLocStart(), + diag::err_typecheck_call_too_many_args) + << 0 /*function call*/ << 2 << TheCall->getNumArgs() + << Fn->getSourceRange() + << SourceRange(TheCall->getArg(2)->getLocStart(), + (*(TheCall->arg_end()-1))->getLocEnd()); + return true; + } + + if (TheCall->getNumArgs() < 2) { + return Diag(TheCall->getLocEnd(), + diag::err_typecheck_call_too_few_args_at_least) + << 0 /*function call*/ << 2 << TheCall->getNumArgs(); + } + + // Type-check the first argument normally. + if (checkBuiltinArgument(*this, TheCall, 0)) + return true; + + // Determine whether the current function is variadic or not. + BlockScopeInfo *CurBlock = getCurBlock(); + bool isVariadic; + if (CurBlock) + isVariadic = CurBlock->TheDecl->isVariadic(); + else if (FunctionDecl *FD = getCurFunctionDecl()) + isVariadic = FD->isVariadic(); + else + isVariadic = getCurMethodDecl()->isVariadic(); + + if (!isVariadic) { + Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); + return true; + } + + // Verify that the second argument to the builtin is the last argument of the + // current function or method. + bool SecondArgIsLastNamedArgument = false; + const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); + + if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { + if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { + // FIXME: This isn't correct for methods (results in bogus warning). + // Get the last formal in the current function. + const ParmVarDecl *LastArg; + if (CurBlock) + LastArg = *(CurBlock->TheDecl->param_end()-1); + else if (FunctionDecl *FD = getCurFunctionDecl()) + LastArg = *(FD->param_end()-1); + else + LastArg = *(getCurMethodDecl()->param_end()-1); + SecondArgIsLastNamedArgument = PV == LastArg; + } + } + + if (!SecondArgIsLastNamedArgument) + Diag(TheCall->getArg(1)->getLocStart(), + diag::warn_second_parameter_of_va_start_not_last_named_argument); + return false; +} + +/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and +/// friends. This is declared to take (...), so we have to check everything. +bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { + if (TheCall->getNumArgs() < 2) + return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) + << 0 << 2 << TheCall->getNumArgs()/*function call*/; + if (TheCall->getNumArgs() > 2) + return Diag(TheCall->getArg(2)->getLocStart(), + diag::err_typecheck_call_too_many_args) + << 0 /*function call*/ << 2 << TheCall->getNumArgs() + << SourceRange(TheCall->getArg(2)->getLocStart(), + (*(TheCall->arg_end()-1))->getLocEnd()); + + ExprResult OrigArg0 = TheCall->getArg(0); + ExprResult OrigArg1 = TheCall->getArg(1); + + // Do standard promotions between the two arguments, returning their common + // type. + QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); + if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) + return true; + + // Make sure any conversions are pushed back into the call; this is + // type safe since unordered compare builtins are declared as "_Bool + // foo(...)". + TheCall->setArg(0, OrigArg0.get()); + TheCall->setArg(1, OrigArg1.get()); + + if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) + return false; + + // If the common type isn't a real floating type, then the arguments were + // invalid for this operation. + if (!Res->isRealFloatingType()) + return Diag(OrigArg0.get()->getLocStart(), + diag::err_typecheck_call_invalid_ordered_compare) + << OrigArg0.get()->getType() << OrigArg1.get()->getType() + << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); + + return false; +} + +/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like +/// __builtin_isnan and friends. This is declared to take (...), so we have +/// to check everything. We expect the last argument to be a floating point +/// value. +bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { + if (TheCall->getNumArgs() < NumArgs) + return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) + << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; + if (TheCall->getNumArgs() > NumArgs) + return Diag(TheCall->getArg(NumArgs)->getLocStart(), + diag::err_typecheck_call_too_many_args) + << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() + << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), + (*(TheCall->arg_end()-1))->getLocEnd()); + + Expr *OrigArg = TheCall->getArg(NumArgs-1); + + if (OrigArg->isTypeDependent()) + return false; + + // This operation requires a non-_Complex floating-point number. + if (!OrigArg->getType()->isRealFloatingType()) + return Diag(OrigArg->getLocStart(), + diag::err_typecheck_call_invalid_unary_fp) + << OrigArg->getType() << OrigArg->getSourceRange(); + + // If this is an implicit conversion from float -> double, remove it. + if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { + Expr *CastArg = Cast->getSubExpr(); + if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { + assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && + "promotion from float to double is the only expected cast here"); + Cast->setSubExpr(0); + TheCall->setArg(NumArgs-1, CastArg); + } + } + + return false; +} + +/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. +// This is declared to take (...), so we have to check everything. +ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { + if (TheCall->getNumArgs() < 2) + return ExprError(Diag(TheCall->getLocEnd(), + diag::err_typecheck_call_too_few_args_at_least) + << 0 /*function call*/ << 2 << TheCall->getNumArgs() + << TheCall->getSourceRange()); + + // Determine which of the following types of shufflevector we're checking: + // 1) unary, vector mask: (lhs, mask) + // 2) binary, vector mask: (lhs, rhs, mask) + // 3) binary, scalar mask: (lhs, rhs, index, ..., index) + QualType resType = TheCall->getArg(0)->getType(); + unsigned numElements = 0; + + if (!TheCall->getArg(0)->isTypeDependent() && + !TheCall->getArg(1)->isTypeDependent()) { + QualType LHSType = TheCall->getArg(0)->getType(); + QualType RHSType = TheCall->getArg(1)->getType(); + + if (!LHSType->isVectorType() || !RHSType->isVectorType()) { + Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) + << SourceRange(TheCall->getArg(0)->getLocStart(), + TheCall->getArg(1)->getLocEnd()); + return ExprError(); + } + + numElements = LHSType->getAs<VectorType>()->getNumElements(); + unsigned numResElements = TheCall->getNumArgs() - 2; + + // Check to see if we have a call with 2 vector arguments, the unary shuffle + // with mask. If so, verify that RHS is an integer vector type with the + // same number of elts as lhs. + if (TheCall->getNumArgs() == 2) { + if (!RHSType->hasIntegerRepresentation() || + RHSType->getAs<VectorType>()->getNumElements() != numElements) + Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) + << SourceRange(TheCall->getArg(1)->getLocStart(), + TheCall->getArg(1)->getLocEnd()); + numResElements = numElements; + } + else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { + Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) + << SourceRange(TheCall->getArg(0)->getLocStart(), + TheCall->getArg(1)->getLocEnd()); + return ExprError(); + } else if (numElements != numResElements) { + QualType eltType = LHSType->getAs<VectorType>()->getElementType(); + resType = Context.getVectorType(eltType, numResElements, + VectorType::GenericVector); + } + } + + for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { + if (TheCall->getArg(i)->isTypeDependent() || + TheCall->getArg(i)->isValueDependent()) + continue; + + llvm::APSInt Result(32); + if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) + return ExprError(Diag(TheCall->getLocStart(), + diag::err_shufflevector_nonconstant_argument) + << TheCall->getArg(i)->getSourceRange()); + + if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) + return ExprError(Diag(TheCall->getLocStart(), + diag::err_shufflevector_argument_too_large) + << TheCall->getArg(i)->getSourceRange()); + } + + SmallVector<Expr*, 32> exprs; + + for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { + exprs.push_back(TheCall->getArg(i)); + TheCall->setArg(i, 0); + } + + return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(), + exprs.size(), resType, + TheCall->getCallee()->getLocStart(), + TheCall->getRParenLoc())); +} + +/// SemaBuiltinPrefetch - Handle __builtin_prefetch. +// This is declared to take (const void*, ...) and can take two +// optional constant int args. +bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { + unsigned NumArgs = TheCall->getNumArgs(); + + if (NumArgs > 3) + return Diag(TheCall->getLocEnd(), + diag::err_typecheck_call_too_many_args_at_most) + << 0 /*function call*/ << 3 << NumArgs + << TheCall->getSourceRange(); + + // Argument 0 is checked for us and the remaining arguments must be + // constant integers. + for (unsigned i = 1; i != NumArgs; ++i) { + Expr *Arg = TheCall->getArg(i); + + llvm::APSInt Result; + if (SemaBuiltinConstantArg(TheCall, i, Result)) + return true; + + // FIXME: gcc issues a warning and rewrites these to 0. These + // seems especially odd for the third argument since the default + // is 3. + if (i == 1) { + if (Result.getLimitedValue() > 1) + return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) + << "0" << "1" << Arg->getSourceRange(); + } else { + if (Result.getLimitedValue() > 3) + return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) + << "0" << "3" << Arg->getSourceRange(); + } + } + + return false; +} + +/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr +/// TheCall is a constant expression. +bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, + llvm::APSInt &Result) { + Expr *Arg = TheCall->getArg(ArgNum); + DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); + FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); + + if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; + + if (!Arg->isIntegerConstantExpr(Result, Context)) + return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) + << FDecl->getDeclName() << Arg->getSourceRange(); + + return false; +} + +/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, +/// int type). This simply type checks that type is one of the defined +/// constants (0-3). +// For compatibility check 0-3, llvm only handles 0 and 2. +bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { + llvm::APSInt Result; + + // Check constant-ness first. + if (SemaBuiltinConstantArg(TheCall, 1, Result)) + return true; + + Expr *Arg = TheCall->getArg(1); + if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { + return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) + << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); + } + + return false; +} + +/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). +/// This checks that val is a constant 1. +bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { + Expr *Arg = TheCall->getArg(1); + llvm::APSInt Result; + + // TODO: This is less than ideal. Overload this to take a value. + if (SemaBuiltinConstantArg(TheCall, 1, Result)) + return true; + + if (Result != 1) + return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) + << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); + + return false; +} + +// Handle i > 1 ? "x" : "y", recursively. +bool Sema::SemaCheckStringLiteral(const Expr *E, Expr **Args, + unsigned NumArgs, bool HasVAListArg, + unsigned format_idx, unsigned firstDataArg, + FormatStringType Type, bool inFunctionCall) { + tryAgain: + if (E->isTypeDependent() || E->isValueDependent()) + return false; + + E = E->IgnoreParenCasts(); + + if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull)) + // Technically -Wformat-nonliteral does not warn about this case. + // The behavior of printf and friends in this case is implementation + // dependent. Ideally if the format string cannot be null then + // it should have a 'nonnull' attribute in the function prototype. + return true; + + switch (E->getStmtClass()) { + case Stmt::BinaryConditionalOperatorClass: + case Stmt::ConditionalOperatorClass: { + const AbstractConditionalOperator *C = cast<AbstractConditionalOperator>(E); + return SemaCheckStringLiteral(C->getTrueExpr(), Args, NumArgs, HasVAListArg, + format_idx, firstDataArg, Type, + inFunctionCall) + && SemaCheckStringLiteral(C->getFalseExpr(), Args, NumArgs, HasVAListArg, + format_idx, firstDataArg, Type, + inFunctionCall); + } + + case Stmt::ImplicitCastExprClass: { + E = cast<ImplicitCastExpr>(E)->getSubExpr(); + goto tryAgain; + } + + case Stmt::OpaqueValueExprClass: + if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { + E = src; + goto tryAgain; + } + return false; + + case Stmt::PredefinedExprClass: + // While __func__, etc., are technically not string literals, they + // cannot contain format specifiers and thus are not a security + // liability. + return true; + + case Stmt::DeclRefExprClass: { + const DeclRefExpr *DR = cast<DeclRefExpr>(E); + + // As an exception, do not flag errors for variables binding to + // const string literals. + if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { + bool isConstant = false; + QualType T = DR->getType(); + + if (const ArrayType *AT = Context.getAsArrayType(T)) { + isConstant = AT->getElementType().isConstant(Context); + } else if (const PointerType *PT = T->getAs<PointerType>()) { + isConstant = T.isConstant(Context) && + PT->getPointeeType().isConstant(Context); + } else if (T->isObjCObjectPointerType()) { + // In ObjC, there is usually no "const ObjectPointer" type, + // so don't check if the pointee type is constant. + isConstant = T.isConstant(Context); + } + + if (isConstant) { + if (const Expr *Init = VD->getAnyInitializer()) + return SemaCheckStringLiteral(Init, Args, NumArgs, + HasVAListArg, format_idx, firstDataArg, + Type, /*inFunctionCall*/false); + } + + // For vprintf* functions (i.e., HasVAListArg==true), we add a + // special check to see if the format string is a function parameter + // of the function calling the printf function. If the function + // has an attribute indicating it is a printf-like function, then we + // should suppress warnings concerning non-literals being used in a call + // to a vprintf function. For example: + // + // void + // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ + // va_list ap; + // va_start(ap, fmt); + // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". + // ... + // + if (HasVAListArg) { + if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { + if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { + int PVIndex = PV->getFunctionScopeIndex() + 1; + for (specific_attr_iterator<FormatAttr> + i = ND->specific_attr_begin<FormatAttr>(), + e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) { + FormatAttr *PVFormat = *i; + // adjust for implicit parameter + if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) + if (MD->isInstance()) + ++PVIndex; + // We also check if the formats are compatible. + // We can't pass a 'scanf' string to a 'printf' function. + if (PVIndex == PVFormat->getFormatIdx() && + Type == GetFormatStringType(PVFormat)) + return true; + } + } + } + } + } + + return false; + } + + case Stmt::CallExprClass: + case Stmt::CXXMemberCallExprClass: { + const CallExpr *CE = cast<CallExpr>(E); + if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { + if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { + unsigned ArgIndex = FA->getFormatIdx(); + if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) + if (MD->isInstance()) + --ArgIndex; + const Expr *Arg = CE->getArg(ArgIndex - 1); + + return SemaCheckStringLiteral(Arg, Args, NumArgs, HasVAListArg, + format_idx, firstDataArg, Type, + inFunctionCall); + } + } + + return false; + } + case Stmt::ObjCStringLiteralClass: + case Stmt::StringLiteralClass: { + const StringLiteral *StrE = NULL; + + if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) + StrE = ObjCFExpr->getString(); + else + StrE = cast<StringLiteral>(E); + + if (StrE) { + CheckFormatString(StrE, E, Args, NumArgs, HasVAListArg, format_idx, + firstDataArg, Type, inFunctionCall); + return true; + } + + return false; + } + + default: + return false; + } +} + +void +Sema::CheckNonNullArguments(const NonNullAttr *NonNull, + const Expr * const *ExprArgs, + SourceLocation CallSiteLoc) { + for (NonNullAttr::args_iterator i = NonNull->args_begin(), + e = NonNull->args_end(); + i != e; ++i) { + const Expr *ArgExpr = ExprArgs[*i]; + if (ArgExpr->isNullPointerConstant(Context, + Expr::NPC_ValueDependentIsNotNull)) + Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); + } +} + +Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { + return llvm::StringSwitch<FormatStringType>(Format->getType()) + .Case("scanf", FST_Scanf) + .Cases("printf", "printf0", FST_Printf) + .Cases("NSString", "CFString", FST_NSString) + .Case("strftime", FST_Strftime) + .Case("strfmon", FST_Strfmon) + .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) + .Default(FST_Unknown); +} + +/// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar +/// functions) for correct use of format strings. +void Sema::CheckFormatArguments(const FormatAttr *Format, CallExpr *TheCall) { + bool IsCXXMember = false; + // The way the format attribute works in GCC, the implicit this argument + // of member functions is counted. However, it doesn't appear in our own + // lists, so decrement format_idx in that case. + IsCXXMember = isa<CXXMemberCallExpr>(TheCall); + CheckFormatArguments(Format, TheCall->getArgs(), TheCall->getNumArgs(), + IsCXXMember, TheCall->getRParenLoc(), + TheCall->getCallee()->getSourceRange()); +} + +void Sema::CheckFormatArguments(const FormatAttr *Format, Expr **Args, + unsigned NumArgs, bool IsCXXMember, + SourceLocation Loc, SourceRange Range) { + bool HasVAListArg = Format->getFirstArg() == 0; + unsigned format_idx = Format->getFormatIdx() - 1; + unsigned firstDataArg = HasVAListArg ? 0 : Format->getFirstArg() - 1; + if (IsCXXMember) { + if (format_idx == 0) + return; + --format_idx; + if(firstDataArg != 0) + --firstDataArg; + } + CheckFormatArguments(Args, NumArgs, HasVAListArg, format_idx, + firstDataArg, GetFormatStringType(Format), Loc, Range); +} + +void Sema::CheckFormatArguments(Expr **Args, unsigned NumArgs, + bool HasVAListArg, unsigned format_idx, + unsigned firstDataArg, FormatStringType Type, + SourceLocation Loc, SourceRange Range) { + // CHECK: printf/scanf-like function is called with no format string. + if (format_idx >= NumArgs) { + Diag(Loc, diag::warn_missing_format_string) << Range; + return; + } + + const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); + + // CHECK: format string is not a string literal. + // + // Dynamically generated format strings are difficult to + // automatically vet at compile time. Requiring that format strings + // are string literals: (1) permits the checking of format strings by + // the compiler and thereby (2) can practically remove the source of + // many format string exploits. + + // Format string can be either ObjC string (e.g. @"%d") or + // C string (e.g. "%d") + // ObjC string uses the same format specifiers as C string, so we can use + // the same format string checking logic for both ObjC and C strings. + if (SemaCheckStringLiteral(OrigFormatExpr, Args, NumArgs, HasVAListArg, + format_idx, firstDataArg, Type)) + return; // Literal format string found, check done! + + // Strftime is particular as it always uses a single 'time' argument, + // so it is safe to pass a non-literal string. + if (Type == FST_Strftime) + return; + + // Do not emit diag when the string param is a macro expansion and the + // format is either NSString or CFString. This is a hack to prevent + // diag when using the NSLocalizedString and CFCopyLocalizedString macros + // which are usually used in place of NS and CF string literals. + if (Type == FST_NSString && Args[format_idx]->getLocStart().isMacroID()) + return; + + // If there are no arguments specified, warn with -Wformat-security, otherwise + // warn only with -Wformat-nonliteral. + if (NumArgs == format_idx+1) + Diag(Args[format_idx]->getLocStart(), + diag::warn_format_nonliteral_noargs) + << OrigFormatExpr->getSourceRange(); + else + Diag(Args[format_idx]->getLocStart(), + diag::warn_format_nonliteral) + << OrigFormatExpr->getSourceRange(); +} + +namespace { +class CheckFormatHandler : public analyze_format_string::FormatStringHandler { +protected: + Sema &S; + const StringLiteral *FExpr; + const Expr *OrigFormatExpr; + const unsigned FirstDataArg; + const unsigned NumDataArgs; + const bool IsObjCLiteral; + const char *Beg; // Start of format string. + const bool HasVAListArg; + const Expr * const *Args; + const unsigned NumArgs; + unsigned FormatIdx; + llvm::BitVector CoveredArgs; + bool usesPositionalArgs; + bool atFirstArg; + bool inFunctionCall; +public: + CheckFormatHandler(Sema &s, const StringLiteral *fexpr, + const Expr *origFormatExpr, unsigned firstDataArg, + unsigned numDataArgs, bool isObjCLiteral, + const char *beg, bool hasVAListArg, + Expr **args, unsigned numArgs, + unsigned formatIdx, bool inFunctionCall) + : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), + FirstDataArg(firstDataArg), + NumDataArgs(numDataArgs), + IsObjCLiteral(isObjCLiteral), Beg(beg), + HasVAListArg(hasVAListArg), + Args(args), NumArgs(numArgs), FormatIdx(formatIdx), + usesPositionalArgs(false), atFirstArg(true), + inFunctionCall(inFunctionCall) { + CoveredArgs.resize(numDataArgs); + CoveredArgs.reset(); + } + + void DoneProcessing(); + + void HandleIncompleteSpecifier(const char *startSpecifier, + unsigned specifierLen); + + void HandleNonStandardLengthModifier( + const analyze_format_string::LengthModifier &LM, + const char *startSpecifier, unsigned specifierLen); + + void HandleNonStandardConversionSpecifier( + const analyze_format_string::ConversionSpecifier &CS, + const char *startSpecifier, unsigned specifierLen); + + void HandleNonStandardConversionSpecification( + const analyze_format_string::LengthModifier &LM, + const analyze_format_string::ConversionSpecifier &CS, + const char *startSpecifier, unsigned specifierLen); + + virtual void HandlePosition(const char *startPos, unsigned posLen); + + virtual void HandleInvalidPosition(const char *startSpecifier, + unsigned specifierLen, + analyze_format_string::PositionContext p); + + virtual void HandleZeroPosition(const char *startPos, unsigned posLen); + + void HandleNullChar(const char *nullCharacter); + + template <typename Range> + static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, + const Expr *ArgumentExpr, + PartialDiagnostic PDiag, + SourceLocation StringLoc, + bool IsStringLocation, Range StringRange, + FixItHint Fixit = FixItHint()); + +protected: + bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, + const char *startSpec, + unsigned specifierLen, + const char *csStart, unsigned csLen); + + void HandlePositionalNonpositionalArgs(SourceLocation Loc, + const char *startSpec, + unsigned specifierLen); + + SourceRange getFormatStringRange(); + CharSourceRange getSpecifierRange(const char *startSpecifier, + unsigned specifierLen); + SourceLocation getLocationOfByte(const char *x); + + const Expr *getDataArg(unsigned i) const; + + bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, + const analyze_format_string::ConversionSpecifier &CS, + const char *startSpecifier, unsigned specifierLen, + unsigned argIndex); + + template <typename Range> + void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, + bool IsStringLocation, Range StringRange, + FixItHint Fixit = FixItHint()); + + void CheckPositionalAndNonpositionalArgs( + const analyze_format_string::FormatSpecifier *FS); +}; +} + +SourceRange CheckFormatHandler::getFormatStringRange() { + return OrigFormatExpr->getSourceRange(); +} + +CharSourceRange CheckFormatHandler:: +getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { + SourceLocation Start = getLocationOfByte(startSpecifier); + SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); + + // Advance the end SourceLocation by one due to half-open ranges. + End = End.getLocWithOffset(1); + + return CharSourceRange::getCharRange(Start, End); +} + +SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { + return S.getLocationOfStringLiteralByte(FExpr, x - Beg); +} + +void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, + unsigned specifierLen){ + EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), + getLocationOfByte(startSpecifier), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); +} + +void CheckFormatHandler::HandleNonStandardLengthModifier( + const analyze_format_string::LengthModifier &LM, + const char *startSpecifier, unsigned specifierLen) { + EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) << LM.toString() + << 0, + getLocationOfByte(LM.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); +} + +void CheckFormatHandler::HandleNonStandardConversionSpecifier( + const analyze_format_string::ConversionSpecifier &CS, + const char *startSpecifier, unsigned specifierLen) { + EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) << CS.toString() + << 1, + getLocationOfByte(CS.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); +} + +void CheckFormatHandler::HandleNonStandardConversionSpecification( + const analyze_format_string::LengthModifier &LM, + const analyze_format_string::ConversionSpecifier &CS, + const char *startSpecifier, unsigned specifierLen) { + EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_conversion_spec) + << LM.toString() << CS.toString(), + getLocationOfByte(LM.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); +} + +void CheckFormatHandler::HandlePosition(const char *startPos, + unsigned posLen) { + EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), + getLocationOfByte(startPos), + /*IsStringLocation*/true, + getSpecifierRange(startPos, posLen)); +} + +void +CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, + analyze_format_string::PositionContext p) { + EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) + << (unsigned) p, + getLocationOfByte(startPos), /*IsStringLocation*/true, + getSpecifierRange(startPos, posLen)); +} + +void CheckFormatHandler::HandleZeroPosition(const char *startPos, + unsigned posLen) { + EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), + getLocationOfByte(startPos), + /*IsStringLocation*/true, + getSpecifierRange(startPos, posLen)); +} + +void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { + if (!IsObjCLiteral) { + // The presence of a null character is likely an error. + EmitFormatDiagnostic( + S.PDiag(diag::warn_printf_format_string_contains_null_char), + getLocationOfByte(nullCharacter), /*IsStringLocation*/true, + getFormatStringRange()); + } +} + +const Expr *CheckFormatHandler::getDataArg(unsigned i) const { + return Args[FirstDataArg + i]; +} + +void CheckFormatHandler::DoneProcessing() { + // Does the number of data arguments exceed the number of + // format conversions in the format string? + if (!HasVAListArg) { + // Find any arguments that weren't covered. + CoveredArgs.flip(); + signed notCoveredArg = CoveredArgs.find_first(); + if (notCoveredArg >= 0) { + assert((unsigned)notCoveredArg < NumDataArgs); + EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), + getDataArg((unsigned) notCoveredArg)->getLocStart(), + /*IsStringLocation*/false, getFormatStringRange()); + } + } +} + +bool +CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, + SourceLocation Loc, + const char *startSpec, + unsigned specifierLen, + const char *csStart, + unsigned csLen) { + + bool keepGoing = true; + if (argIndex < NumDataArgs) { + // Consider the argument coverered, even though the specifier doesn't + // make sense. + CoveredArgs.set(argIndex); + } + else { + // If argIndex exceeds the number of data arguments we + // don't issue a warning because that is just a cascade of warnings (and + // they may have intended '%%' anyway). We don't want to continue processing + // the format string after this point, however, as we will like just get + // gibberish when trying to match arguments. + keepGoing = false; + } + + EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) + << StringRef(csStart, csLen), + Loc, /*IsStringLocation*/true, + getSpecifierRange(startSpec, specifierLen)); + + return keepGoing; +} + +void +CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, + const char *startSpec, + unsigned specifierLen) { + EmitFormatDiagnostic( + S.PDiag(diag::warn_format_mix_positional_nonpositional_args), + Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); +} + +bool +CheckFormatHandler::CheckNumArgs( + const analyze_format_string::FormatSpecifier &FS, + const analyze_format_string::ConversionSpecifier &CS, + const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { + + if (argIndex >= NumDataArgs) { + PartialDiagnostic PDiag = FS.usesPositionalArg() + ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) + << (argIndex+1) << NumDataArgs) + : S.PDiag(diag::warn_printf_insufficient_data_args); + EmitFormatDiagnostic( + PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); + return false; + } + return true; +} + +template<typename Range> +void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, + SourceLocation Loc, + bool IsStringLocation, + Range StringRange, + FixItHint FixIt) { + EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, + Loc, IsStringLocation, StringRange, FixIt); +} + +/// \brief If the format string is not within the funcion call, emit a note +/// so that the function call and string are in diagnostic messages. +/// +/// \param inFunctionCall if true, the format string is within the function +/// call and only one diagnostic message will be produced. Otherwise, an +/// extra note will be emitted pointing to location of the format string. +/// +/// \param ArgumentExpr the expression that is passed as the format string +/// argument in the function call. Used for getting locations when two +/// diagnostics are emitted. +/// +/// \param PDiag the callee should already have provided any strings for the +/// diagnostic message. This function only adds locations and fixits +/// to diagnostics. +/// +/// \param Loc primary location for diagnostic. If two diagnostics are +/// required, one will be at Loc and a new SourceLocation will be created for +/// the other one. +/// +/// \param IsStringLocation if true, Loc points to the format string should be +/// used for the note. Otherwise, Loc points to the argument list and will +/// be used with PDiag. +/// +/// \param StringRange some or all of the string to highlight. This is +/// templated so it can accept either a CharSourceRange or a SourceRange. +/// +/// \param Fixit optional fix it hint for the format string. +template<typename Range> +void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, + const Expr *ArgumentExpr, + PartialDiagnostic PDiag, + SourceLocation Loc, + bool IsStringLocation, + Range StringRange, + FixItHint FixIt) { + if (InFunctionCall) + S.Diag(Loc, PDiag) << StringRange << FixIt; + else { + S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) + << ArgumentExpr->getSourceRange(); + S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), + diag::note_format_string_defined) + << StringRange << FixIt; + } +} + +//===--- CHECK: Printf format string checking ------------------------------===// + +namespace { +class CheckPrintfHandler : public CheckFormatHandler { +public: + CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, + const Expr *origFormatExpr, unsigned firstDataArg, + unsigned numDataArgs, bool isObjCLiteral, + const char *beg, bool hasVAListArg, + Expr **Args, unsigned NumArgs, + unsigned formatIdx, bool inFunctionCall) + : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, + numDataArgs, isObjCLiteral, beg, hasVAListArg, + Args, NumArgs, formatIdx, inFunctionCall) {} + + + bool HandleInvalidPrintfConversionSpecifier( + const analyze_printf::PrintfSpecifier &FS, + const char *startSpecifier, + unsigned specifierLen); + + bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, + const char *startSpecifier, + unsigned specifierLen); + + bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, + const char *startSpecifier, unsigned specifierLen); + void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, + const analyze_printf::OptionalAmount &Amt, + unsigned type, + const char *startSpecifier, unsigned specifierLen); + void HandleFlag(const analyze_printf::PrintfSpecifier &FS, + const analyze_printf::OptionalFlag &flag, + const char *startSpecifier, unsigned specifierLen); + void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, + const analyze_printf::OptionalFlag &ignoredFlag, + const analyze_printf::OptionalFlag &flag, + const char *startSpecifier, unsigned specifierLen); +}; +} + +bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( + const analyze_printf::PrintfSpecifier &FS, + const char *startSpecifier, + unsigned specifierLen) { + const analyze_printf::PrintfConversionSpecifier &CS = + FS.getConversionSpecifier(); + + return HandleInvalidConversionSpecifier(FS.getArgIndex(), + getLocationOfByte(CS.getStart()), + startSpecifier, specifierLen, + CS.getStart(), CS.getLength()); +} + +bool CheckPrintfHandler::HandleAmount( + const analyze_format_string::OptionalAmount &Amt, + unsigned k, const char *startSpecifier, + unsigned specifierLen) { + + if (Amt.hasDataArgument()) { + if (!HasVAListArg) { + unsigned argIndex = Amt.getArgIndex(); + if (argIndex >= NumDataArgs) { + EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) + << k, + getLocationOfByte(Amt.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); + // Don't do any more checking. We will just emit + // spurious errors. + return false; + } + + // Type check the data argument. It should be an 'int'. + // Although not in conformance with C99, we also allow the argument to be + // an 'unsigned int' as that is a reasonably safe case. GCC also + // doesn't emit a warning for that case. + CoveredArgs.set(argIndex); + const Expr *Arg = getDataArg(argIndex); + QualType T = Arg->getType(); + + const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context); + assert(ATR.isValid()); + + if (!ATR.matchesType(S.Context, T)) { + EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) + << k << ATR.getRepresentativeTypeName(S.Context) + << T << Arg->getSourceRange(), + getLocationOfByte(Amt.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); + // Don't do any more checking. We will just emit + // spurious errors. + return false; + } + } + } + return true; +} + +void CheckPrintfHandler::HandleInvalidAmount( + const analyze_printf::PrintfSpecifier &FS, + const analyze_printf::OptionalAmount &Amt, + unsigned type, + const char *startSpecifier, + unsigned specifierLen) { + const analyze_printf::PrintfConversionSpecifier &CS = + FS.getConversionSpecifier(); + + FixItHint fixit = + Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant + ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), + Amt.getConstantLength())) + : FixItHint(); + + EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) + << type << CS.toString(), + getLocationOfByte(Amt.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen), + fixit); +} + +void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, + const analyze_printf::OptionalFlag &flag, + const char *startSpecifier, + unsigned specifierLen) { + // Warn about pointless flag with a fixit removal. + const analyze_printf::PrintfConversionSpecifier &CS = + FS.getConversionSpecifier(); + EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) + << flag.toString() << CS.toString(), + getLocationOfByte(flag.getPosition()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen), + FixItHint::CreateRemoval( + getSpecifierRange(flag.getPosition(), 1))); +} + +void CheckPrintfHandler::HandleIgnoredFlag( + const analyze_printf::PrintfSpecifier &FS, + const analyze_printf::OptionalFlag &ignoredFlag, + const analyze_printf::OptionalFlag &flag, + const char *startSpecifier, + unsigned specifierLen) { + // Warn about ignored flag with a fixit removal. + EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) + << ignoredFlag.toString() << flag.toString(), + getLocationOfByte(ignoredFlag.getPosition()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen), + FixItHint::CreateRemoval( + getSpecifierRange(ignoredFlag.getPosition(), 1))); +} + +bool +CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier + &FS, + const char *startSpecifier, + unsigned specifierLen) { + + using namespace analyze_format_string; + using namespace analyze_printf; + const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); + + if (FS.consumesDataArgument()) { + if (atFirstArg) { + atFirstArg = false; + usesPositionalArgs = FS.usesPositionalArg(); + } + else if (usesPositionalArgs != FS.usesPositionalArg()) { + HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), + startSpecifier, specifierLen); + return false; + } + } + + // First check if the field width, precision, and conversion specifier + // have matching data arguments. + if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, + startSpecifier, specifierLen)) { + return false; + } + + if (!HandleAmount(FS.getPrecision(), /* precision */ 1, + startSpecifier, specifierLen)) { + return false; + } + + if (!CS.consumesDataArgument()) { + // FIXME: Technically specifying a precision or field width here + // makes no sense. Worth issuing a warning at some point. + return true; + } + + // Consume the argument. + unsigned argIndex = FS.getArgIndex(); + if (argIndex < NumDataArgs) { + // The check to see if the argIndex is valid will come later. + // We set the bit here because we may exit early from this + // function if we encounter some other error. + CoveredArgs.set(argIndex); + } + + // Check for using an Objective-C specific conversion specifier + // in a non-ObjC literal. + if (!IsObjCLiteral && CS.isObjCArg()) { + return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, + specifierLen); + } + + // Check for invalid use of field width + if (!FS.hasValidFieldWidth()) { + HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, + startSpecifier, specifierLen); + } + + // Check for invalid use of precision + if (!FS.hasValidPrecision()) { + HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, + startSpecifier, specifierLen); + } + + // Check each flag does not conflict with any other component. + if (!FS.hasValidThousandsGroupingPrefix()) + HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); + if (!FS.hasValidLeadingZeros()) + HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); + if (!FS.hasValidPlusPrefix()) + HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); + if (!FS.hasValidSpacePrefix()) + HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); + if (!FS.hasValidAlternativeForm()) + HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); + if (!FS.hasValidLeftJustified()) + HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); + + // Check that flags are not ignored by another flag + if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' + HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), + startSpecifier, specifierLen); + if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' + HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), + startSpecifier, specifierLen); + + // Check the length modifier is valid with the given conversion specifier. + const LengthModifier &LM = FS.getLengthModifier(); + if (!FS.hasValidLengthModifier()) + EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length) + << LM.toString() << CS.toString(), + getLocationOfByte(LM.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen), + FixItHint::CreateRemoval( + getSpecifierRange(LM.getStart(), + LM.getLength()))); + if (!FS.hasStandardLengthModifier()) + HandleNonStandardLengthModifier(LM, startSpecifier, specifierLen); + if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) + HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); + if (!FS.hasStandardLengthConversionCombination()) + HandleNonStandardConversionSpecification(LM, CS, startSpecifier, + specifierLen); + + // Are we using '%n'? + if (CS.getKind() == ConversionSpecifier::nArg) { + // Issue a warning about this being a possible security issue. + EmitFormatDiagnostic(S.PDiag(diag::warn_printf_write_back), + getLocationOfByte(CS.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); + // Continue checking the other format specifiers. + return true; + } + + // The remaining checks depend on the data arguments. + if (HasVAListArg) + return true; + + if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) + return false; + + // Now type check the data expression that matches the + // format specifier. + const Expr *Ex = getDataArg(argIndex); + const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context, + IsObjCLiteral); + if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) { + // Check if we didn't match because of an implicit cast from a 'char' + // or 'short' to an 'int'. This is done because printf is a varargs + // function. + if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Ex)) + if (ICE->getType() == S.Context.IntTy) { + // All further checking is done on the subexpression. + Ex = ICE->getSubExpr(); + if (ATR.matchesType(S.Context, Ex->getType())) + return true; + } + + // We may be able to offer a FixItHint if it is a supported type. + PrintfSpecifier fixedFS = FS; + bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), + S.Context, IsObjCLiteral); + + if (success) { + // Get the fix string from the fixed format specifier + SmallString<128> buf; + llvm::raw_svector_ostream os(buf); + fixedFS.toString(os); + + EmitFormatDiagnostic( + S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) + << ATR.getRepresentativeTypeName(S.Context) << Ex->getType() + << Ex->getSourceRange(), + getLocationOfByte(CS.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen), + FixItHint::CreateReplacement( + getSpecifierRange(startSpecifier, specifierLen), + os.str())); + } + else { + EmitFormatDiagnostic( + S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) + << ATR.getRepresentativeTypeName(S.Context) << Ex->getType() + << getSpecifierRange(startSpecifier, specifierLen) + << Ex->getSourceRange(), + getLocationOfByte(CS.getStart()), + true, + getSpecifierRange(startSpecifier, specifierLen)); + } + } + + return true; +} + +//===--- CHECK: Scanf format string checking ------------------------------===// + +namespace { +class CheckScanfHandler : public CheckFormatHandler { +public: + CheckScanfHandler(Sema &s, const StringLiteral *fexpr, + const Expr *origFormatExpr, unsigned firstDataArg, + unsigned numDataArgs, bool isObjCLiteral, + const char *beg, bool hasVAListArg, + Expr **Args, unsigned NumArgs, + unsigned formatIdx, bool inFunctionCall) + : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, + numDataArgs, isObjCLiteral, beg, hasVAListArg, + Args, NumArgs, formatIdx, inFunctionCall) {} + + bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, + const char *startSpecifier, + unsigned specifierLen); + + bool HandleInvalidScanfConversionSpecifier( + const analyze_scanf::ScanfSpecifier &FS, + const char *startSpecifier, + unsigned specifierLen); + + void HandleIncompleteScanList(const char *start, const char *end); +}; +} + +void CheckScanfHandler::HandleIncompleteScanList(const char *start, + const char *end) { + EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), + getLocationOfByte(end), /*IsStringLocation*/true, + getSpecifierRange(start, end - start)); +} + +bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( + const analyze_scanf::ScanfSpecifier &FS, + const char *startSpecifier, + unsigned specifierLen) { + + const analyze_scanf::ScanfConversionSpecifier &CS = + FS.getConversionSpecifier(); + + return HandleInvalidConversionSpecifier(FS.getArgIndex(), + getLocationOfByte(CS.getStart()), + startSpecifier, specifierLen, + CS.getStart(), CS.getLength()); +} + +bool CheckScanfHandler::HandleScanfSpecifier( + const analyze_scanf::ScanfSpecifier &FS, + const char *startSpecifier, + unsigned specifierLen) { + + using namespace analyze_scanf; + using namespace analyze_format_string; + + const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); + + // Handle case where '%' and '*' don't consume an argument. These shouldn't + // be used to decide if we are using positional arguments consistently. + if (FS.consumesDataArgument()) { + if (atFirstArg) { + atFirstArg = false; + usesPositionalArgs = FS.usesPositionalArg(); + } + else if (usesPositionalArgs != FS.usesPositionalArg()) { + HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), + startSpecifier, specifierLen); + return false; + } + } + + // Check if the field with is non-zero. + const OptionalAmount &Amt = FS.getFieldWidth(); + if (Amt.getHowSpecified() == OptionalAmount::Constant) { + if (Amt.getConstantAmount() == 0) { + const CharSourceRange &R = getSpecifierRange(Amt.getStart(), + Amt.getConstantLength()); + EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), + getLocationOfByte(Amt.getStart()), + /*IsStringLocation*/true, R, + FixItHint::CreateRemoval(R)); + } + } + + if (!FS.consumesDataArgument()) { + // FIXME: Technically specifying a precision or field width here + // makes no sense. Worth issuing a warning at some point. + return true; + } + + // Consume the argument. + unsigned argIndex = FS.getArgIndex(); + if (argIndex < NumDataArgs) { + // The check to see if the argIndex is valid will come later. + // We set the bit here because we may exit early from this + // function if we encounter some other error. + CoveredArgs.set(argIndex); + } + + // Check the length modifier is valid with the given conversion specifier. + const LengthModifier &LM = FS.getLengthModifier(); + if (!FS.hasValidLengthModifier()) { + const CharSourceRange &R = getSpecifierRange(LM.getStart(), LM.getLength()); + EmitFormatDiagnostic(S.PDiag(diag::warn_format_nonsensical_length) + << LM.toString() << CS.toString() + << getSpecifierRange(startSpecifier, specifierLen), + getLocationOfByte(LM.getStart()), + /*IsStringLocation*/true, R, + FixItHint::CreateRemoval(R)); + } + + if (!FS.hasStandardLengthModifier()) + HandleNonStandardLengthModifier(LM, startSpecifier, specifierLen); + if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) + HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); + if (!FS.hasStandardLengthConversionCombination()) + HandleNonStandardConversionSpecification(LM, CS, startSpecifier, + specifierLen); + + // The remaining checks depend on the data arguments. + if (HasVAListArg) + return true; + + if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) + return false; + + // Check that the argument type matches the format specifier. + const Expr *Ex = getDataArg(argIndex); + const analyze_scanf::ScanfArgTypeResult &ATR = FS.getArgType(S.Context); + if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) { + ScanfSpecifier fixedFS = FS; + bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), + S.Context); + + if (success) { + // Get the fix string from the fixed format specifier. + SmallString<128> buf; + llvm::raw_svector_ostream os(buf); + fixedFS.toString(os); + + EmitFormatDiagnostic( + S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) + << ATR.getRepresentativeTypeName(S.Context) << Ex->getType() + << Ex->getSourceRange(), + getLocationOfByte(CS.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen), + FixItHint::CreateReplacement( + getSpecifierRange(startSpecifier, specifierLen), + os.str())); + } else { + EmitFormatDiagnostic( + S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) + << ATR.getRepresentativeTypeName(S.Context) << Ex->getType() + << Ex->getSourceRange(), + getLocationOfByte(CS.getStart()), + /*IsStringLocation*/true, + getSpecifierRange(startSpecifier, specifierLen)); + } + } + + return true; +} + +void Sema::CheckFormatString(const StringLiteral *FExpr, + const Expr *OrigFormatExpr, + Expr **Args, unsigned NumArgs, + bool HasVAListArg, unsigned format_idx, + unsigned firstDataArg, FormatStringType Type, + bool inFunctionCall) { + + // CHECK: is the format string a wide literal? + if (!FExpr->isAscii()) { + CheckFormatHandler::EmitFormatDiagnostic( + *this, inFunctionCall, Args[format_idx], + PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), + /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); + return; + } + + // Str - The format string. NOTE: this is NOT null-terminated! + StringRef StrRef = FExpr->getString(); + const char *Str = StrRef.data(); + unsigned StrLen = StrRef.size(); + const unsigned numDataArgs = NumArgs - firstDataArg; + + // CHECK: empty format string? + if (StrLen == 0 && numDataArgs > 0) { + CheckFormatHandler::EmitFormatDiagnostic( + *this, inFunctionCall, Args[format_idx], + PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), + /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); + return; + } + + if (Type == FST_Printf || Type == FST_NSString) { + CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, + numDataArgs, isa<ObjCStringLiteral>(OrigFormatExpr), + Str, HasVAListArg, Args, NumArgs, format_idx, + inFunctionCall); + + if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, + getLangOpts())) + H.DoneProcessing(); + } else if (Type == FST_Scanf) { + CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, + numDataArgs, isa<ObjCStringLiteral>(OrigFormatExpr), + Str, HasVAListArg, Args, NumArgs, format_idx, + inFunctionCall); + + if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, + getLangOpts())) + H.DoneProcessing(); + } // TODO: handle other formats +} + +//===--- CHECK: Standard memory functions ---------------------------------===// + +/// \brief Determine whether the given type is a dynamic class type (e.g., +/// whether it has a vtable). +static bool isDynamicClassType(QualType T) { + if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) + if (CXXRecordDecl *Definition = Record->getDefinition()) + if (Definition->isDynamicClass()) + return true; + + return false; +} + +/// \brief If E is a sizeof expression, returns its argument expression, +/// otherwise returns NULL. +static const Expr *getSizeOfExprArg(const Expr* E) { + if (const UnaryExprOrTypeTraitExpr *SizeOf = + dyn_cast<UnaryExprOrTypeTraitExpr>(E)) + if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) + return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); + + return 0; +} + +/// \brief If E is a sizeof expression, returns its argument type. +static QualType getSizeOfArgType(const Expr* E) { + if (const UnaryExprOrTypeTraitExpr *SizeOf = + dyn_cast<UnaryExprOrTypeTraitExpr>(E)) + if (SizeOf->getKind() == clang::UETT_SizeOf) + return SizeOf->getTypeOfArgument(); + + return QualType(); +} + +/// \brief Check for dangerous or invalid arguments to memset(). +/// +/// This issues warnings on known problematic, dangerous or unspecified +/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' +/// function calls. +/// +/// \param Call The call expression to diagnose. +void Sema::CheckMemaccessArguments(const CallExpr *Call, + unsigned BId, + IdentifierInfo *FnName) { + assert(BId != 0); + + // It is possible to have a non-standard definition of memset. Validate + // we have enough arguments, and if not, abort further checking. + unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); + if (Call->getNumArgs() < ExpectedNumArgs) + return; + + unsigned LastArg = (BId == Builtin::BImemset || + BId == Builtin::BIstrndup ? 1 : 2); + unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); + const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); + + // We have special checking when the length is a sizeof expression. + QualType SizeOfArgTy = getSizeOfArgType(LenExpr); + const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); + llvm::FoldingSetNodeID SizeOfArgID; + + for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { + const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); + SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); + + QualType DestTy = Dest->getType(); + if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { + QualType PointeeTy = DestPtrTy->getPointeeType(); + + // Never warn about void type pointers. This can be used to suppress + // false positives. + if (PointeeTy->isVoidType()) + continue; + + // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by + // actually comparing the expressions for equality. Because computing the + // expression IDs can be expensive, we only do this if the diagnostic is + // enabled. + if (SizeOfArg && + Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, + SizeOfArg->getExprLoc())) { + // We only compute IDs for expressions if the warning is enabled, and + // cache the sizeof arg's ID. + if (SizeOfArgID == llvm::FoldingSetNodeID()) + SizeOfArg->Profile(SizeOfArgID, Context, true); + llvm::FoldingSetNodeID DestID; + Dest->Profile(DestID, Context, true); + if (DestID == SizeOfArgID) { + // TODO: For strncpy() and friends, this could suggest sizeof(dst) + // over sizeof(src) as well. + unsigned ActionIdx = 0; // Default is to suggest dereferencing. + if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) + if (UnaryOp->getOpcode() == UO_AddrOf) + ActionIdx = 1; // If its an address-of operator, just remove it. + if (Context.getTypeSize(PointeeTy) == Context.getCharWidth()) + ActionIdx = 2; // If the pointee's size is sizeof(char), + // suggest an explicit length. + unsigned DestSrcSelect = + (BId == Builtin::BIstrndup ? 1 : ArgIdx); + DiagRuntimeBehavior(SizeOfArg->getExprLoc(), Dest, + PDiag(diag::warn_sizeof_pointer_expr_memaccess) + << FnName << DestSrcSelect << ActionIdx + << Dest->getSourceRange() + << SizeOfArg->getSourceRange()); + break; + } + } + + // Also check for cases where the sizeof argument is the exact same + // type as the memory argument, and where it points to a user-defined + // record type. + if (SizeOfArgTy != QualType()) { + if (PointeeTy->isRecordType() && + Context.typesAreCompatible(SizeOfArgTy, DestTy)) { + DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, + PDiag(diag::warn_sizeof_pointer_type_memaccess) + << FnName << SizeOfArgTy << ArgIdx + << PointeeTy << Dest->getSourceRange() + << LenExpr->getSourceRange()); + break; + } + } + + // Always complain about dynamic classes. + if (isDynamicClassType(PointeeTy)) { + + unsigned OperationType = 0; + // "overwritten" if we're warning about the destination for any call + // but memcmp; otherwise a verb appropriate to the call. + if (ArgIdx != 0 || BId == Builtin::BImemcmp) { + if (BId == Builtin::BImemcpy) + OperationType = 1; + else if(BId == Builtin::BImemmove) + OperationType = 2; + else if (BId == Builtin::BImemcmp) + OperationType = 3; + } + + DiagRuntimeBehavior( + Dest->getExprLoc(), Dest, + PDiag(diag::warn_dyn_class_memaccess) + << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) + << FnName << PointeeTy + << OperationType + << Call->getCallee()->getSourceRange()); + } else if (PointeeTy.hasNonTrivialObjCLifetime() && + BId != Builtin::BImemset) + DiagRuntimeBehavior( + Dest->getExprLoc(), Dest, + PDiag(diag::warn_arc_object_memaccess) + << ArgIdx << FnName << PointeeTy + << Call->getCallee()->getSourceRange()); + else + continue; + + DiagRuntimeBehavior( + Dest->getExprLoc(), Dest, + PDiag(diag::note_bad_memaccess_silence) + << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); + break; + } + } +} + +// A little helper routine: ignore addition and subtraction of integer literals. +// This intentionally does not ignore all integer constant expressions because +// we don't want to remove sizeof(). +static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { + Ex = Ex->IgnoreParenCasts(); + + for (;;) { + const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); + if (!BO || !BO->isAdditiveOp()) + break; + + const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); + const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); + + if (isa<IntegerLiteral>(RHS)) + Ex = LHS; + else if (isa<IntegerLiteral>(LHS)) + Ex = RHS; + else + break; + } + + return Ex; +} + +// Warn if the user has made the 'size' argument to strlcpy or strlcat +// be the size of the source, instead of the destination. +void Sema::CheckStrlcpycatArguments(const CallExpr *Call, + IdentifierInfo *FnName) { + + // Don't crash if the user has the wrong number of arguments + if (Call->getNumArgs() != 3) + return; + + const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); + const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); + const Expr *CompareWithSrc = NULL; + + // Look for 'strlcpy(dst, x, sizeof(x))' + if (const Expr *Ex = getSizeOfExprArg(SizeArg)) + CompareWithSrc = Ex; + else { + // Look for 'strlcpy(dst, x, strlen(x))' + if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { + if (SizeCall->isBuiltinCall() == Builtin::BIstrlen + && SizeCall->getNumArgs() == 1) + CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); + } + } + + if (!CompareWithSrc) + return; + + // Determine if the argument to sizeof/strlen is equal to the source + // argument. In principle there's all kinds of things you could do + // here, for instance creating an == expression and evaluating it with + // EvaluateAsBooleanCondition, but this uses a more direct technique: + const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); + if (!SrcArgDRE) + return; + + const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); + if (!CompareWithSrcDRE || + SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) + return; + + const Expr *OriginalSizeArg = Call->getArg(2); + Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) + << OriginalSizeArg->getSourceRange() << FnName; + + // Output a FIXIT hint if the destination is an array (rather than a + // pointer to an array). This could be enhanced to handle some + // pointers if we know the actual size, like if DstArg is 'array+2' + // we could say 'sizeof(array)-2'. + const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); + QualType DstArgTy = DstArg->getType(); + + // Only handle constant-sized or VLAs, but not flexible members. + if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(DstArgTy)) { + // Only issue the FIXIT for arrays of size > 1. + if (CAT->getSize().getSExtValue() <= 1) + return; + } else if (!DstArgTy->isVariableArrayType()) { + return; + } + + SmallString<128> sizeString; + llvm::raw_svector_ostream OS(sizeString); + OS << "sizeof("; + DstArg->printPretty(OS, Context, 0, getPrintingPolicy()); + OS << ")"; + + Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) + << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), + OS.str()); +} + +/// Check if two expressions refer to the same declaration. +static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { + if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) + if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) + return D1->getDecl() == D2->getDecl(); + return false; +} + +static const Expr *getStrlenExprArg(const Expr *E) { + if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { + const FunctionDecl *FD = CE->getDirectCallee(); + if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) + return 0; + return CE->getArg(0)->IgnoreParenCasts(); + } + return 0; +} + +// Warn on anti-patterns as the 'size' argument to strncat. +// The correct size argument should look like following: +// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); +void Sema::CheckStrncatArguments(const CallExpr *CE, + IdentifierInfo *FnName) { + // Don't crash if the user has the wrong number of arguments. + if (CE->getNumArgs() < 3) + return; + const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); + const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); + const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); + + // Identify common expressions, which are wrongly used as the size argument + // to strncat and may lead to buffer overflows. + unsigned PatternType = 0; + if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { + // - sizeof(dst) + if (referToTheSameDecl(SizeOfArg, DstArg)) + PatternType = 1; + // - sizeof(src) + else if (referToTheSameDecl(SizeOfArg, SrcArg)) + PatternType = 2; + } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { + if (BE->getOpcode() == BO_Sub) { + const Expr *L = BE->getLHS()->IgnoreParenCasts(); + const Expr *R = BE->getRHS()->IgnoreParenCasts(); + // - sizeof(dst) - strlen(dst) + if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && + referToTheSameDecl(DstArg, getStrlenExprArg(R))) + PatternType = 1; + // - sizeof(src) - (anything) + else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) + PatternType = 2; + } + } + + if (PatternType == 0) + return; + + // Generate the diagnostic. + SourceLocation SL = LenArg->getLocStart(); + SourceRange SR = LenArg->getSourceRange(); + SourceManager &SM = PP.getSourceManager(); + + // If the function is defined as a builtin macro, do not show macro expansion. + if (SM.isMacroArgExpansion(SL)) { + SL = SM.getSpellingLoc(SL); + SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), + SM.getSpellingLoc(SR.getEnd())); + } + + if (PatternType == 1) + Diag(SL, diag::warn_strncat_large_size) << SR; + else + Diag(SL, diag::warn_strncat_src_size) << SR; + + // Output a FIXIT hint if the destination is an array (rather than a + // pointer to an array). This could be enhanced to handle some + // pointers if we know the actual size, like if DstArg is 'array+2' + // we could say 'sizeof(array)-2'. + QualType DstArgTy = DstArg->getType(); + + // Only handle constant-sized or VLAs, but not flexible members. + if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(DstArgTy)) { + // Only issue the FIXIT for arrays of size > 1. + if (CAT->getSize().getSExtValue() <= 1) + return; + } else if (!DstArgTy->isVariableArrayType()) { + return; + } + + SmallString<128> sizeString; + llvm::raw_svector_ostream OS(sizeString); + OS << "sizeof("; + DstArg->printPretty(OS, Context, 0, getPrintingPolicy()); + OS << ") - "; + OS << "strlen("; + DstArg->printPretty(OS, Context, 0, getPrintingPolicy()); + OS << ") - 1"; + + Diag(SL, diag::note_strncat_wrong_size) + << FixItHint::CreateReplacement(SR, OS.str()); +} + +//===--- CHECK: Return Address of Stack Variable --------------------------===// + +static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars); +static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars); + +/// CheckReturnStackAddr - Check if a return statement returns the address +/// of a stack variable. +void +Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, + SourceLocation ReturnLoc) { + + Expr *stackE = 0; + SmallVector<DeclRefExpr *, 8> refVars; + + // Perform checking for returned stack addresses, local blocks, + // label addresses or references to temporaries. + if (lhsType->isPointerType() || + (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { + stackE = EvalAddr(RetValExp, refVars); + } else if (lhsType->isReferenceType()) { + stackE = EvalVal(RetValExp, refVars); + } + + if (stackE == 0) + return; // Nothing suspicious was found. + + SourceLocation diagLoc; + SourceRange diagRange; + if (refVars.empty()) { + diagLoc = stackE->getLocStart(); + diagRange = stackE->getSourceRange(); + } else { + // We followed through a reference variable. 'stackE' contains the + // problematic expression but we will warn at the return statement pointing + // at the reference variable. We will later display the "trail" of + // reference variables using notes. + diagLoc = refVars[0]->getLocStart(); + diagRange = refVars[0]->getSourceRange(); + } + + if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. + Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref + : diag::warn_ret_stack_addr) + << DR->getDecl()->getDeclName() << diagRange; + } else if (isa<BlockExpr>(stackE)) { // local block. + Diag(diagLoc, diag::err_ret_local_block) << diagRange; + } else if (isa<AddrLabelExpr>(stackE)) { // address of label. + Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; + } else { // local temporary. + Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref + : diag::warn_ret_local_temp_addr) + << diagRange; + } + + // Display the "trail" of reference variables that we followed until we + // found the problematic expression using notes. + for (unsigned i = 0, e = refVars.size(); i != e; ++i) { + VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); + // If this var binds to another reference var, show the range of the next + // var, otherwise the var binds to the problematic expression, in which case + // show the range of the expression. + SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() + : stackE->getSourceRange(); + Diag(VD->getLocation(), diag::note_ref_var_local_bind) + << VD->getDeclName() << range; + } +} + +/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that +/// check if the expression in a return statement evaluates to an address +/// to a location on the stack, a local block, an address of a label, or a +/// reference to local temporary. The recursion is used to traverse the +/// AST of the return expression, with recursion backtracking when we +/// encounter a subexpression that (1) clearly does not lead to one of the +/// above problematic expressions (2) is something we cannot determine leads to +/// a problematic expression based on such local checking. +/// +/// Both EvalAddr and EvalVal follow through reference variables to evaluate +/// the expression that they point to. Such variables are added to the +/// 'refVars' vector so that we know what the reference variable "trail" was. +/// +/// EvalAddr processes expressions that are pointers that are used as +/// references (and not L-values). EvalVal handles all other values. +/// At the base case of the recursion is a check for the above problematic +/// expressions. +/// +/// This implementation handles: +/// +/// * pointer-to-pointer casts +/// * implicit conversions from array references to pointers +/// * taking the address of fields +/// * arbitrary interplay between "&" and "*" operators +/// * pointer arithmetic from an address of a stack variable +/// * taking the address of an array element where the array is on the stack +static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars) { + if (E->isTypeDependent()) + return NULL; + + // We should only be called for evaluating pointer expressions. + assert((E->getType()->isAnyPointerType() || + E->getType()->isBlockPointerType() || + E->getType()->isObjCQualifiedIdType()) && + "EvalAddr only works on pointers"); + + E = E->IgnoreParens(); + + // Our "symbolic interpreter" is just a dispatch off the currently + // viewed AST node. We then recursively traverse the AST by calling + // EvalAddr and EvalVal appropriately. + switch (E->getStmtClass()) { + case Stmt::DeclRefExprClass: { + DeclRefExpr *DR = cast<DeclRefExpr>(E); + + if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) + // If this is a reference variable, follow through to the expression that + // it points to. + if (V->hasLocalStorage() && + V->getType()->isReferenceType() && V->hasInit()) { + // Add the reference variable to the "trail". + refVars.push_back(DR); + return EvalAddr(V->getInit(), refVars); + } + + return NULL; + } + + case Stmt::UnaryOperatorClass: { + // The only unary operator that make sense to handle here + // is AddrOf. All others don't make sense as pointers. + UnaryOperator *U = cast<UnaryOperator>(E); + + if (U->getOpcode() == UO_AddrOf) + return EvalVal(U->getSubExpr(), refVars); + else + return NULL; + } + + case Stmt::BinaryOperatorClass: { + // Handle pointer arithmetic. All other binary operators are not valid + // in this context. + BinaryOperator *B = cast<BinaryOperator>(E); + BinaryOperatorKind op = B->getOpcode(); + + if (op != BO_Add && op != BO_Sub) + return NULL; + + Expr *Base = B->getLHS(); + + // Determine which argument is the real pointer base. It could be + // the RHS argument instead of the LHS. + if (!Base->getType()->isPointerType()) Base = B->getRHS(); + + assert (Base->getType()->isPointerType()); + return EvalAddr(Base, refVars); + } + + // For conditional operators we need to see if either the LHS or RHS are + // valid DeclRefExpr*s. If one of them is valid, we return it. + case Stmt::ConditionalOperatorClass: { + ConditionalOperator *C = cast<ConditionalOperator>(E); + + // Handle the GNU extension for missing LHS. + if (Expr *lhsExpr = C->getLHS()) { + // In C++, we can have a throw-expression, which has 'void' type. + if (!lhsExpr->getType()->isVoidType()) + if (Expr* LHS = EvalAddr(lhsExpr, refVars)) + return LHS; + } + + // In C++, we can have a throw-expression, which has 'void' type. + if (C->getRHS()->getType()->isVoidType()) + return NULL; + + return EvalAddr(C->getRHS(), refVars); + } + + case Stmt::BlockExprClass: + if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) + return E; // local block. + return NULL; + + case Stmt::AddrLabelExprClass: + return E; // address of label. + + case Stmt::ExprWithCleanupsClass: + return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars); + + // For casts, we need to handle conversions from arrays to + // pointer values, and pointer-to-pointer conversions. + case Stmt::ImplicitCastExprClass: + case Stmt::CStyleCastExprClass: + case Stmt::CXXFunctionalCastExprClass: + case Stmt::ObjCBridgedCastExprClass: + case Stmt::CXXStaticCastExprClass: + case Stmt::CXXDynamicCastExprClass: + case Stmt::CXXConstCastExprClass: + case Stmt::CXXReinterpretCastExprClass: { + Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); + switch (cast<CastExpr>(E)->getCastKind()) { + case CK_BitCast: + case CK_LValueToRValue: + case CK_NoOp: + case CK_BaseToDerived: + case CK_DerivedToBase: + case CK_UncheckedDerivedToBase: + case CK_Dynamic: + case CK_CPointerToObjCPointerCast: + case CK_BlockPointerToObjCPointerCast: + case CK_AnyPointerToBlockPointerCast: + return EvalAddr(SubExpr, refVars); + + case CK_ArrayToPointerDecay: + return EvalVal(SubExpr, refVars); + + default: + return 0; + } + } + + case Stmt::MaterializeTemporaryExprClass: + if (Expr *Result = EvalAddr( + cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), + refVars)) + return Result; + + return E; + + // Everything else: we simply don't reason about them. + default: + return NULL; + } +} + + +/// EvalVal - This function is complements EvalAddr in the mutual recursion. +/// See the comments for EvalAddr for more details. +static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars) { +do { + // We should only be called for evaluating non-pointer expressions, or + // expressions with a pointer type that are not used as references but instead + // are l-values (e.g., DeclRefExpr with a pointer type). + + // Our "symbolic interpreter" is just a dispatch off the currently + // viewed AST node. We then recursively traverse the AST by calling + // EvalAddr and EvalVal appropriately. + + E = E->IgnoreParens(); + switch (E->getStmtClass()) { + case Stmt::ImplicitCastExprClass: { + ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); + if (IE->getValueKind() == VK_LValue) { + E = IE->getSubExpr(); + continue; + } + return NULL; + } + + case Stmt::ExprWithCleanupsClass: + return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars); + + case Stmt::DeclRefExprClass: { + // When we hit a DeclRefExpr we are looking at code that refers to a + // variable's name. If it's not a reference variable we check if it has + // local storage within the function, and if so, return the expression. + DeclRefExpr *DR = cast<DeclRefExpr>(E); + + if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) + if (V->hasLocalStorage()) { + if (!V->getType()->isReferenceType()) + return DR; + + // Reference variable, follow through to the expression that + // it points to. + if (V->hasInit()) { + // Add the reference variable to the "trail". + refVars.push_back(DR); + return EvalVal(V->getInit(), refVars); + } + } + + return NULL; + } + + case Stmt::UnaryOperatorClass: { + // The only unary operator that make sense to handle here + // is Deref. All others don't resolve to a "name." This includes + // handling all sorts of rvalues passed to a unary operator. + UnaryOperator *U = cast<UnaryOperator>(E); + + if (U->getOpcode() == UO_Deref) + return EvalAddr(U->getSubExpr(), refVars); + + return NULL; + } + + case Stmt::ArraySubscriptExprClass: { + // Array subscripts are potential references to data on the stack. We + // retrieve the DeclRefExpr* for the array variable if it indeed + // has local storage. + return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars); + } + + case Stmt::ConditionalOperatorClass: { + // For conditional operators we need to see if either the LHS or RHS are + // non-NULL Expr's. If one is non-NULL, we return it. + ConditionalOperator *C = cast<ConditionalOperator>(E); + + // Handle the GNU extension for missing LHS. + if (Expr *lhsExpr = C->getLHS()) + if (Expr *LHS = EvalVal(lhsExpr, refVars)) + return LHS; + + return EvalVal(C->getRHS(), refVars); + } + + // Accesses to members are potential references to data on the stack. + case Stmt::MemberExprClass: { + MemberExpr *M = cast<MemberExpr>(E); + + // Check for indirect access. We only want direct field accesses. + if (M->isArrow()) + return NULL; + + // Check whether the member type is itself a reference, in which case + // we're not going to refer to the member, but to what the member refers to. + if (M->getMemberDecl()->getType()->isReferenceType()) + return NULL; + + return EvalVal(M->getBase(), refVars); + } + + case Stmt::MaterializeTemporaryExprClass: + if (Expr *Result = EvalVal( + cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), + refVars)) + return Result; + + return E; + + default: + // Check that we don't return or take the address of a reference to a + // temporary. This is only useful in C++. + if (!E->isTypeDependent() && E->isRValue()) + return E; + + // Everything else: we simply don't reason about them. + return NULL; + } +} while (true); +} + +//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// + +/// Check for comparisons of floating point operands using != and ==. +/// Issue a warning if these are no self-comparisons, as they are not likely +/// to do what the programmer intended. +void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { + bool EmitWarning = true; + + Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); + Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); + + // Special case: check for x == x (which is OK). + // Do not emit warnings for such cases. + if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) + if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) + if (DRL->getDecl() == DRR->getDecl()) + EmitWarning = false; + + + // Special case: check for comparisons against literals that can be exactly + // represented by APFloat. In such cases, do not emit a warning. This + // is a heuristic: often comparison against such literals are used to + // detect if a value in a variable has not changed. This clearly can + // lead to false negatives. + if (EmitWarning) { + if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { + if (FLL->isExact()) + EmitWarning = false; + } else + if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){ + if (FLR->isExact()) + EmitWarning = false; + } + } + + // Check for comparisons with builtin types. + if (EmitWarning) + if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) + if (CL->isBuiltinCall()) + EmitWarning = false; + + if (EmitWarning) + if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) + if (CR->isBuiltinCall()) + EmitWarning = false; + + // Emit the diagnostic. + if (EmitWarning) + Diag(Loc, diag::warn_floatingpoint_eq) + << LHS->getSourceRange() << RHS->getSourceRange(); +} + +//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// +//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// + +namespace { + +/// Structure recording the 'active' range of an integer-valued +/// expression. +struct IntRange { + /// The number of bits active in the int. + unsigned Width; + + /// True if the int is known not to have negative values. + bool NonNegative; + + IntRange(unsigned Width, bool NonNegative) + : Width(Width), NonNegative(NonNegative) + {} + + /// Returns the range of the bool type. + static IntRange forBoolType() { + return IntRange(1, true); + } + + /// Returns the range of an opaque value of the given integral type. + static IntRange forValueOfType(ASTContext &C, QualType T) { + return forValueOfCanonicalType(C, + T->getCanonicalTypeInternal().getTypePtr()); + } + + /// Returns the range of an opaque value of a canonical integral type. + static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { + assert(T->isCanonicalUnqualified()); + + if (const VectorType *VT = dyn_cast<VectorType>(T)) + T = VT->getElementType().getTypePtr(); + if (const ComplexType *CT = dyn_cast<ComplexType>(T)) + T = CT->getElementType().getTypePtr(); + + // For enum types, use the known bit width of the enumerators. + if (const EnumType *ET = dyn_cast<EnumType>(T)) { + EnumDecl *Enum = ET->getDecl(); + if (!Enum->isCompleteDefinition()) + return IntRange(C.getIntWidth(QualType(T, 0)), false); + + unsigned NumPositive = Enum->getNumPositiveBits(); + unsigned NumNegative = Enum->getNumNegativeBits(); + + return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0); + } + + const BuiltinType *BT = cast<BuiltinType>(T); + assert(BT->isInteger()); + + return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); + } + + /// Returns the "target" range of a canonical integral type, i.e. + /// the range of values expressible in the type. + /// + /// This matches forValueOfCanonicalType except that enums have the + /// full range of their type, not the range of their enumerators. + static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { + assert(T->isCanonicalUnqualified()); + + if (const VectorType *VT = dyn_cast<VectorType>(T)) + T = VT->getElementType().getTypePtr(); + if (const ComplexType *CT = dyn_cast<ComplexType>(T)) + T = CT->getElementType().getTypePtr(); + if (const EnumType *ET = dyn_cast<EnumType>(T)) + T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); + + const BuiltinType *BT = cast<BuiltinType>(T); + assert(BT->isInteger()); + + return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); + } + + /// Returns the supremum of two ranges: i.e. their conservative merge. + static IntRange join(IntRange L, IntRange R) { + return IntRange(std::max(L.Width, R.Width), + L.NonNegative && R.NonNegative); + } + + /// Returns the infinum of two ranges: i.e. their aggressive merge. + static IntRange meet(IntRange L, IntRange R) { + return IntRange(std::min(L.Width, R.Width), + L.NonNegative || R.NonNegative); + } +}; + +static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, + unsigned MaxWidth) { + if (value.isSigned() && value.isNegative()) + return IntRange(value.getMinSignedBits(), false); + + if (value.getBitWidth() > MaxWidth) + value = value.trunc(MaxWidth); + + // isNonNegative() just checks the sign bit without considering + // signedness. + return IntRange(value.getActiveBits(), true); +} + +static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, + unsigned MaxWidth) { + if (result.isInt()) + return GetValueRange(C, result.getInt(), MaxWidth); + + if (result.isVector()) { + IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); + for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { + IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); + R = IntRange::join(R, El); + } + return R; + } + + if (result.isComplexInt()) { + IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); + IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); + return IntRange::join(R, I); + } + + // This can happen with lossless casts to intptr_t of "based" lvalues. + // Assume it might use arbitrary bits. + // FIXME: The only reason we need to pass the type in here is to get + // the sign right on this one case. It would be nice if APValue + // preserved this. + assert(result.isLValue() || result.isAddrLabelDiff()); + return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); +} + +/// Pseudo-evaluate the given integer expression, estimating the +/// range of values it might take. +/// +/// \param MaxWidth - the width to which the value will be truncated +static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { + E = E->IgnoreParens(); + + // Try a full evaluation first. + Expr::EvalResult result; + if (E->EvaluateAsRValue(result, C)) + return GetValueRange(C, result.Val, E->getType(), MaxWidth); + + // I think we only want to look through implicit casts here; if the + // user has an explicit widening cast, we should treat the value as + // being of the new, wider type. + if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { + if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) + return GetExprRange(C, CE->getSubExpr(), MaxWidth); + + IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType()); + + bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); + + // Assume that non-integer casts can span the full range of the type. + if (!isIntegerCast) + return OutputTypeRange; + + IntRange SubRange + = GetExprRange(C, CE->getSubExpr(), + std::min(MaxWidth, OutputTypeRange.Width)); + + // Bail out if the subexpr's range is as wide as the cast type. + if (SubRange.Width >= OutputTypeRange.Width) + return OutputTypeRange; + + // Otherwise, we take the smaller width, and we're non-negative if + // either the output type or the subexpr is. + return IntRange(SubRange.Width, + SubRange.NonNegative || OutputTypeRange.NonNegative); + } + + if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { + // If we can fold the condition, just take that operand. + bool CondResult; + if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) + return GetExprRange(C, CondResult ? CO->getTrueExpr() + : CO->getFalseExpr(), + MaxWidth); + + // Otherwise, conservatively merge. + IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); + IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); + return IntRange::join(L, R); + } + + if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { + switch (BO->getOpcode()) { + + // Boolean-valued operations are single-bit and positive. + case BO_LAnd: + case BO_LOr: + case BO_LT: + case BO_GT: + case BO_LE: + case BO_GE: + case BO_EQ: + case BO_NE: + return IntRange::forBoolType(); + + // The type of the assignments is the type of the LHS, so the RHS + // is not necessarily the same type. + case BO_MulAssign: + case BO_DivAssign: + case BO_RemAssign: + case BO_AddAssign: + case BO_SubAssign: + case BO_XorAssign: + case BO_OrAssign: + // TODO: bitfields? + return IntRange::forValueOfType(C, E->getType()); + + // Simple assignments just pass through the RHS, which will have + // been coerced to the LHS type. + case BO_Assign: + // TODO: bitfields? + return GetExprRange(C, BO->getRHS(), MaxWidth); + + // Operations with opaque sources are black-listed. + case BO_PtrMemD: + case BO_PtrMemI: + return IntRange::forValueOfType(C, E->getType()); + + // Bitwise-and uses the *infinum* of the two source ranges. + case BO_And: + case BO_AndAssign: + return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), + GetExprRange(C, BO->getRHS(), MaxWidth)); + + // Left shift gets black-listed based on a judgement call. + case BO_Shl: + // ...except that we want to treat '1 << (blah)' as logically + // positive. It's an important idiom. + if (IntegerLiteral *I + = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { + if (I->getValue() == 1) { + IntRange R = IntRange::forValueOfType(C, E->getType()); + return IntRange(R.Width, /*NonNegative*/ true); + } + } + // fallthrough + + case BO_ShlAssign: + return IntRange::forValueOfType(C, E->getType()); + + // Right shift by a constant can narrow its left argument. + case BO_Shr: + case BO_ShrAssign: { + IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); + + // If the shift amount is a positive constant, drop the width by + // that much. + llvm::APSInt shift; + if (BO->getRHS()->isIntegerConstantExpr(shift, C) && + shift.isNonNegative()) { + unsigned zext = shift.getZExtValue(); + if (zext >= L.Width) + L.Width = (L.NonNegative ? 0 : 1); + else + L.Width -= zext; + } + + return L; + } + + // Comma acts as its right operand. + case BO_Comma: + return GetExprRange(C, BO->getRHS(), MaxWidth); + + // Black-list pointer subtractions. + case BO_Sub: + if (BO->getLHS()->getType()->isPointerType()) + return IntRange::forValueOfType(C, E->getType()); + break; + + // The width of a division result is mostly determined by the size + // of the LHS. + case BO_Div: { + // Don't 'pre-truncate' the operands. + unsigned opWidth = C.getIntWidth(E->getType()); + IntRange L = GetExprRange(C, BO->getLHS(), opWidth); + + // If the divisor is constant, use that. + llvm::APSInt divisor; + if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { + unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) + if (log2 >= L.Width) + L.Width = (L.NonNegative ? 0 : 1); + else + L.Width = std::min(L.Width - log2, MaxWidth); + return L; + } + + // Otherwise, just use the LHS's width. + IntRange R = GetExprRange(C, BO->getRHS(), opWidth); + return IntRange(L.Width, L.NonNegative && R.NonNegative); + } + + // The result of a remainder can't be larger than the result of + // either side. + case BO_Rem: { + // Don't 'pre-truncate' the operands. + unsigned opWidth = C.getIntWidth(E->getType()); + IntRange L = GetExprRange(C, BO->getLHS(), opWidth); + IntRange R = GetExprRange(C, BO->getRHS(), opWidth); + + IntRange meet = IntRange::meet(L, R); + meet.Width = std::min(meet.Width, MaxWidth); + return meet; + } + + // The default behavior is okay for these. + case BO_Mul: + case BO_Add: + case BO_Xor: + case BO_Or: + break; + } + + // The default case is to treat the operation as if it were closed + // on the narrowest type that encompasses both operands. + IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); + IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); + return IntRange::join(L, R); + } + + if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { + switch (UO->getOpcode()) { + // Boolean-valued operations are white-listed. + case UO_LNot: + return IntRange::forBoolType(); + + // Operations with opaque sources are black-listed. + case UO_Deref: + case UO_AddrOf: // should be impossible + return IntRange::forValueOfType(C, E->getType()); + + default: + return GetExprRange(C, UO->getSubExpr(), MaxWidth); + } + } + + if (dyn_cast<OffsetOfExpr>(E)) { + IntRange::forValueOfType(C, E->getType()); + } + + if (FieldDecl *BitField = E->getBitField()) + return IntRange(BitField->getBitWidthValue(C), + BitField->getType()->isUnsignedIntegerOrEnumerationType()); + + return IntRange::forValueOfType(C, E->getType()); +} + +static IntRange GetExprRange(ASTContext &C, Expr *E) { + return GetExprRange(C, E, C.getIntWidth(E->getType())); +} + +/// Checks whether the given value, which currently has the given +/// source semantics, has the same value when coerced through the +/// target semantics. +static bool IsSameFloatAfterCast(const llvm::APFloat &value, + const llvm::fltSemantics &Src, + const llvm::fltSemantics &Tgt) { + llvm::APFloat truncated = value; + + bool ignored; + truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); + truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); + + return truncated.bitwiseIsEqual(value); +} + +/// Checks whether the given value, which currently has the given +/// source semantics, has the same value when coerced through the +/// target semantics. +/// +/// The value might be a vector of floats (or a complex number). +static bool IsSameFloatAfterCast(const APValue &value, + const llvm::fltSemantics &Src, + const llvm::fltSemantics &Tgt) { + if (value.isFloat()) + return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); + + if (value.isVector()) { + for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) + if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) + return false; + return true; + } + + assert(value.isComplexFloat()); + return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && + IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); +} + +static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); + +static bool IsZero(Sema &S, Expr *E) { + // Suppress cases where we are comparing against an enum constant. + if (const DeclRefExpr *DR = + dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) + if (isa<EnumConstantDecl>(DR->getDecl())) + return false; + + // Suppress cases where the '0' value is expanded from a macro. + if (E->getLocStart().isMacroID()) + return false; + + llvm::APSInt Value; + return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; +} + +static bool HasEnumType(Expr *E) { + // Strip off implicit integral promotions. + while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { + if (ICE->getCastKind() != CK_IntegralCast && + ICE->getCastKind() != CK_NoOp) + break; + E = ICE->getSubExpr(); + } + + return E->getType()->isEnumeralType(); +} + +static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { + BinaryOperatorKind op = E->getOpcode(); + if (E->isValueDependent()) + return; + + if (op == BO_LT && IsZero(S, E->getRHS())) { + S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) + << "< 0" << "false" << HasEnumType(E->getLHS()) + << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); + } else if (op == BO_GE && IsZero(S, E->getRHS())) { + S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) + << ">= 0" << "true" << HasEnumType(E->getLHS()) + << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); + } else if (op == BO_GT && IsZero(S, E->getLHS())) { + S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) + << "0 >" << "false" << HasEnumType(E->getRHS()) + << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); + } else if (op == BO_LE && IsZero(S, E->getLHS())) { + S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) + << "0 <=" << "true" << HasEnumType(E->getRHS()) + << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); + } +} + +/// Analyze the operands of the given comparison. Implements the +/// fallback case from AnalyzeComparison. +static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { + AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); + AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); +} + +/// \brief Implements -Wsign-compare. +/// +/// \param E the binary operator to check for warnings +static void AnalyzeComparison(Sema &S, BinaryOperator *E) { + // The type the comparison is being performed in. + QualType T = E->getLHS()->getType(); + assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) + && "comparison with mismatched types"); + + // We don't do anything special if this isn't an unsigned integral + // comparison: we're only interested in integral comparisons, and + // signed comparisons only happen in cases we don't care to warn about. + // + // We also don't care about value-dependent expressions or expressions + // whose result is a constant. + if (!T->hasUnsignedIntegerRepresentation() + || E->isValueDependent() || E->isIntegerConstantExpr(S.Context)) + return AnalyzeImpConvsInComparison(S, E); + + Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); + Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); + + // Check to see if one of the (unmodified) operands is of different + // signedness. + Expr *signedOperand, *unsignedOperand; + if (LHS->getType()->hasSignedIntegerRepresentation()) { + assert(!RHS->getType()->hasSignedIntegerRepresentation() && + "unsigned comparison between two signed integer expressions?"); + signedOperand = LHS; + unsignedOperand = RHS; + } else if (RHS->getType()->hasSignedIntegerRepresentation()) { + signedOperand = RHS; + unsignedOperand = LHS; + } else { + CheckTrivialUnsignedComparison(S, E); + return AnalyzeImpConvsInComparison(S, E); + } + + // Otherwise, calculate the effective range of the signed operand. + IntRange signedRange = GetExprRange(S.Context, signedOperand); + + // Go ahead and analyze implicit conversions in the operands. Note + // that we skip the implicit conversions on both sides. + AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); + AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); + + // If the signed range is non-negative, -Wsign-compare won't fire, + // but we should still check for comparisons which are always true + // or false. + if (signedRange.NonNegative) + return CheckTrivialUnsignedComparison(S, E); + + // For (in)equality comparisons, if the unsigned operand is a + // constant which cannot collide with a overflowed signed operand, + // then reinterpreting the signed operand as unsigned will not + // change the result of the comparison. + if (E->isEqualityOp()) { + unsigned comparisonWidth = S.Context.getIntWidth(T); + IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); + + // We should never be unable to prove that the unsigned operand is + // non-negative. + assert(unsignedRange.NonNegative && "unsigned range includes negative?"); + + if (unsignedRange.Width < comparisonWidth) + return; + } + + S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison) + << LHS->getType() << RHS->getType() + << LHS->getSourceRange() << RHS->getSourceRange(); +} + +/// Analyzes an attempt to assign the given value to a bitfield. +/// +/// Returns true if there was something fishy about the attempt. +static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, + SourceLocation InitLoc) { + assert(Bitfield->isBitField()); + if (Bitfield->isInvalidDecl()) + return false; + + // White-list bool bitfields. + if (Bitfield->getType()->isBooleanType()) + return false; + + // Ignore value- or type-dependent expressions. + if (Bitfield->getBitWidth()->isValueDependent() || + Bitfield->getBitWidth()->isTypeDependent() || + Init->isValueDependent() || + Init->isTypeDependent()) + return false; + + Expr *OriginalInit = Init->IgnoreParenImpCasts(); + + llvm::APSInt Value; + if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) + return false; + + unsigned OriginalWidth = Value.getBitWidth(); + unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); + + if (OriginalWidth <= FieldWidth) + return false; + + // Compute the value which the bitfield will contain. + llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); + TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); + + // Check whether the stored value is equal to the original value. + TruncatedValue = TruncatedValue.extend(OriginalWidth); + if (Value == TruncatedValue) + return false; + + // Special-case bitfields of width 1: booleans are naturally 0/1, and + // therefore don't strictly fit into a signed bitfield of width 1. + if (FieldWidth == 1 && Value == 1) + return false; + + std::string PrettyValue = Value.toString(10); + std::string PrettyTrunc = TruncatedValue.toString(10); + + S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) + << PrettyValue << PrettyTrunc << OriginalInit->getType() + << Init->getSourceRange(); + + return true; +} + +/// Analyze the given simple or compound assignment for warning-worthy +/// operations. +static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { + // Just recurse on the LHS. + AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); + + // We want to recurse on the RHS as normal unless we're assigning to + // a bitfield. + if (FieldDecl *Bitfield = E->getLHS()->getBitField()) { + if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), + E->getOperatorLoc())) { + // Recurse, ignoring any implicit conversions on the RHS. + return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), + E->getOperatorLoc()); + } + } + + AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); +} + +/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. +static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, + SourceLocation CContext, unsigned diag, + bool pruneControlFlow = false) { + if (pruneControlFlow) { + S.DiagRuntimeBehavior(E->getExprLoc(), E, + S.PDiag(diag) + << SourceType << T << E->getSourceRange() + << SourceRange(CContext)); + return; + } + S.Diag(E->getExprLoc(), diag) + << SourceType << T << E->getSourceRange() << SourceRange(CContext); +} + +/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. +static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, + SourceLocation CContext, unsigned diag, + bool pruneControlFlow = false) { + DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); +} + +/// Diagnose an implicit cast from a literal expression. Does not warn when the +/// cast wouldn't lose information. +void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, + SourceLocation CContext) { + // Try to convert the literal exactly to an integer. If we can, don't warn. + bool isExact = false; + const llvm::APFloat &Value = FL->getValue(); + llvm::APSInt IntegerValue(S.Context.getIntWidth(T), + T->hasUnsignedIntegerRepresentation()); + if (Value.convertToInteger(IntegerValue, + llvm::APFloat::rmTowardZero, &isExact) + == llvm::APFloat::opOK && isExact) + return; + + S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) + << FL->getType() << T << FL->getSourceRange() << SourceRange(CContext); +} + +std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { + if (!Range.Width) return "0"; + + llvm::APSInt ValueInRange = Value; + ValueInRange.setIsSigned(!Range.NonNegative); + ValueInRange = ValueInRange.trunc(Range.Width); + return ValueInRange.toString(10); +} + +void CheckImplicitConversion(Sema &S, Expr *E, QualType T, + SourceLocation CC, bool *ICContext = 0) { + if (E->isTypeDependent() || E->isValueDependent()) return; + + const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); + const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); + if (Source == Target) return; + if (Target->isDependentType()) return; + + // If the conversion context location is invalid don't complain. We also + // don't want to emit a warning if the issue occurs from the expansion of + // a system macro. The problem is that 'getSpellingLoc()' is slow, so we + // delay this check as long as possible. Once we detect we are in that + // scenario, we just return. + if (CC.isInvalid()) + return; + + // Diagnose implicit casts to bool. + if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { + if (isa<StringLiteral>(E)) + // Warn on string literal to bool. Checks for string literals in logical + // expressions, for instances, assert(0 && "error here"), is prevented + // by a check in AnalyzeImplicitConversions(). + return DiagnoseImpCast(S, E, T, CC, + diag::warn_impcast_string_literal_to_bool); + if (Source->isFunctionType()) { + // Warn on function to bool. Checks free functions and static member + // functions. Weakly imported functions are excluded from the check, + // since it's common to test their value to check whether the linker + // found a definition for them. + ValueDecl *D = 0; + if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { + D = R->getDecl(); + } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { + D = M->getMemberDecl(); + } + + if (D && !D->isWeak()) { + if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { + S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) + << F << E->getSourceRange() << SourceRange(CC); + S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) + << FixItHint::CreateInsertion(E->getExprLoc(), "&"); + QualType ReturnType; + UnresolvedSet<4> NonTemplateOverloads; + S.isExprCallable(*E, ReturnType, NonTemplateOverloads); + if (!ReturnType.isNull() + && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) + S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) + << FixItHint::CreateInsertion( + S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); + return; + } + } + } + return; // Other casts to bool are not checked. + } + + // Strip vector types. + if (isa<VectorType>(Source)) { + if (!isa<VectorType>(Target)) { + if (S.SourceMgr.isInSystemMacro(CC)) + return; + return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); + } + + // If the vector cast is cast between two vectors of the same size, it is + // a bitcast, not a conversion. + if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) + return; + + Source = cast<VectorType>(Source)->getElementType().getTypePtr(); + Target = cast<VectorType>(Target)->getElementType().getTypePtr(); + } + + // Strip complex types. + if (isa<ComplexType>(Source)) { + if (!isa<ComplexType>(Target)) { + if (S.SourceMgr.isInSystemMacro(CC)) + return; + + return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); + } + + Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); + Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); + } + + const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); + const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); + + // If the source is floating point... + if (SourceBT && SourceBT->isFloatingPoint()) { + // ...and the target is floating point... + if (TargetBT && TargetBT->isFloatingPoint()) { + // ...then warn if we're dropping FP rank. + + // Builtin FP kinds are ordered by increasing FP rank. + if (SourceBT->getKind() > TargetBT->getKind()) { + // Don't warn about float constants that are precisely + // representable in the target type. + Expr::EvalResult result; + if (E->EvaluateAsRValue(result, S.Context)) { + // Value might be a float, a float vector, or a float complex. + if (IsSameFloatAfterCast(result.Val, + S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), + S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) + return; + } + + if (S.SourceMgr.isInSystemMacro(CC)) + return; + + DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); + } + return; + } + + // If the target is integral, always warn. + if ((TargetBT && TargetBT->isInteger())) { + if (S.SourceMgr.isInSystemMacro(CC)) + return; + + Expr *InnerE = E->IgnoreParenImpCasts(); + // We also want to warn on, e.g., "int i = -1.234" + if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) + if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) + InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); + + if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { + DiagnoseFloatingLiteralImpCast(S, FL, T, CC); + } else { + DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); + } + } + + return; + } + + if (!Source->isIntegerType() || !Target->isIntegerType()) + return; + + if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) + == Expr::NPCK_GNUNull) && Target->isIntegerType()) { + SourceLocation Loc = E->getSourceRange().getBegin(); + if (Loc.isMacroID()) + Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; + S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) + << T << Loc << clang::SourceRange(CC); + return; + } + + IntRange SourceRange = GetExprRange(S.Context, E); + IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); + + if (SourceRange.Width > TargetRange.Width) { + // If the source is a constant, use a default-on diagnostic. + // TODO: this should happen for bitfield stores, too. + llvm::APSInt Value(32); + if (E->isIntegerConstantExpr(Value, S.Context)) { + if (S.SourceMgr.isInSystemMacro(CC)) + return; + + std::string PrettySourceValue = Value.toString(10); + std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); + + S.DiagRuntimeBehavior(E->getExprLoc(), E, + S.PDiag(diag::warn_impcast_integer_precision_constant) + << PrettySourceValue << PrettyTargetValue + << E->getType() << T << E->getSourceRange() + << clang::SourceRange(CC)); + return; + } + + // People want to build with -Wshorten-64-to-32 and not -Wconversion. + if (S.SourceMgr.isInSystemMacro(CC)) + return; + + if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) + return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, + /* pruneControlFlow */ true); + return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); + } + + if ((TargetRange.NonNegative && !SourceRange.NonNegative) || + (!TargetRange.NonNegative && SourceRange.NonNegative && + SourceRange.Width == TargetRange.Width)) { + + if (S.SourceMgr.isInSystemMacro(CC)) + return; + + unsigned DiagID = diag::warn_impcast_integer_sign; + + // Traditionally, gcc has warned about this under -Wsign-compare. + // We also want to warn about it in -Wconversion. + // So if -Wconversion is off, use a completely identical diagnostic + // in the sign-compare group. + // The conditional-checking code will + if (ICContext) { + DiagID = diag::warn_impcast_integer_sign_conditional; + *ICContext = true; + } + + return DiagnoseImpCast(S, E, T, CC, DiagID); + } + + // Diagnose conversions between different enumeration types. + // In C, we pretend that the type of an EnumConstantDecl is its enumeration + // type, to give us better diagnostics. + QualType SourceType = E->getType(); + if (!S.getLangOpts().CPlusPlus) { + if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) + if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { + EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); + SourceType = S.Context.getTypeDeclType(Enum); + Source = S.Context.getCanonicalType(SourceType).getTypePtr(); + } + } + + if (const EnumType *SourceEnum = Source->getAs<EnumType>()) + if (const EnumType *TargetEnum = Target->getAs<EnumType>()) + if ((SourceEnum->getDecl()->getIdentifier() || + SourceEnum->getDecl()->getTypedefNameForAnonDecl()) && + (TargetEnum->getDecl()->getIdentifier() || + TargetEnum->getDecl()->getTypedefNameForAnonDecl()) && + SourceEnum != TargetEnum) { + if (S.SourceMgr.isInSystemMacro(CC)) + return; + + return DiagnoseImpCast(S, E, SourceType, T, CC, + diag::warn_impcast_different_enum_types); + } + + return; +} + +void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T); + +void CheckConditionalOperand(Sema &S, Expr *E, QualType T, + SourceLocation CC, bool &ICContext) { + E = E->IgnoreParenImpCasts(); + + if (isa<ConditionalOperator>(E)) + return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T); + + AnalyzeImplicitConversions(S, E, CC); + if (E->getType() != T) + return CheckImplicitConversion(S, E, T, CC, &ICContext); + return; +} + +void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) { + SourceLocation CC = E->getQuestionLoc(); + + AnalyzeImplicitConversions(S, E->getCond(), CC); + + bool Suspicious = false; + CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); + CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); + + // If -Wconversion would have warned about either of the candidates + // for a signedness conversion to the context type... + if (!Suspicious) return; + + // ...but it's currently ignored... + if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, + CC)) + return; + + // ...then check whether it would have warned about either of the + // candidates for a signedness conversion to the condition type. + if (E->getType() == T) return; + + Suspicious = false; + CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), + E->getType(), CC, &Suspicious); + if (!Suspicious) + CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), + E->getType(), CC, &Suspicious); +} + +/// AnalyzeImplicitConversions - Find and report any interesting +/// implicit conversions in the given expression. There are a couple +/// of competing diagnostics here, -Wconversion and -Wsign-compare. +void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { + QualType T = OrigE->getType(); + Expr *E = OrigE->IgnoreParenImpCasts(); + + if (E->isTypeDependent() || E->isValueDependent()) + return; + + // For conditional operators, we analyze the arguments as if they + // were being fed directly into the output. + if (isa<ConditionalOperator>(E)) { + ConditionalOperator *CO = cast<ConditionalOperator>(E); + CheckConditionalOperator(S, CO, T); + return; + } + + // Go ahead and check any implicit conversions we might have skipped. + // The non-canonical typecheck is just an optimization; + // CheckImplicitConversion will filter out dead implicit conversions. + if (E->getType() != T) + CheckImplicitConversion(S, E, T, CC); + + // Now continue drilling into this expression. + + // Skip past explicit casts. + if (isa<ExplicitCastExpr>(E)) { + E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); + return AnalyzeImplicitConversions(S, E, CC); + } + + if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { + // Do a somewhat different check with comparison operators. + if (BO->isComparisonOp()) + return AnalyzeComparison(S, BO); + + // And with simple assignments. + if (BO->getOpcode() == BO_Assign) + return AnalyzeAssignment(S, BO); + } + + // These break the otherwise-useful invariant below. Fortunately, + // we don't really need to recurse into them, because any internal + // expressions should have been analyzed already when they were + // built into statements. + if (isa<StmtExpr>(E)) return; + + // Don't descend into unevaluated contexts. + if (isa<UnaryExprOrTypeTraitExpr>(E)) return; + + // Now just recurse over the expression's children. + CC = E->getExprLoc(); + BinaryOperator *BO = dyn_cast<BinaryOperator>(E); + bool IsLogicalOperator = BO && BO->isLogicalOp(); + for (Stmt::child_range I = E->children(); I; ++I) { + Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); + if (!ChildExpr) + continue; + + if (IsLogicalOperator && + isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) + // Ignore checking string literals that are in logical operators. + continue; + AnalyzeImplicitConversions(S, ChildExpr, CC); + } +} + +} // end anonymous namespace + +/// Diagnoses "dangerous" implicit conversions within the given +/// expression (which is a full expression). Implements -Wconversion +/// and -Wsign-compare. +/// +/// \param CC the "context" location of the implicit conversion, i.e. +/// the most location of the syntactic entity requiring the implicit +/// conversion +void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { + // Don't diagnose in unevaluated contexts. + if (ExprEvalContexts.back().Context == Sema::Unevaluated) + return; + + // Don't diagnose for value- or type-dependent expressions. + if (E->isTypeDependent() || E->isValueDependent()) + return; + + // Check for array bounds violations in cases where the check isn't triggered + // elsewhere for other Expr types (like BinaryOperators), e.g. when an + // ArraySubscriptExpr is on the RHS of a variable initialization. + CheckArrayAccess(E); + + // This is not the right CC for (e.g.) a variable initialization. + AnalyzeImplicitConversions(*this, E, CC); +} + +void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, + FieldDecl *BitField, + Expr *Init) { + (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); +} + +/// CheckParmsForFunctionDef - Check that the parameters of the given +/// function are appropriate for the definition of a function. This +/// takes care of any checks that cannot be performed on the +/// declaration itself, e.g., that the types of each of the function +/// parameters are complete. +bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd, + bool CheckParameterNames) { + bool HasInvalidParm = false; + for (; P != PEnd; ++P) { + ParmVarDecl *Param = *P; + + // C99 6.7.5.3p4: the parameters in a parameter type list in a + // function declarator that is part of a function definition of + // that function shall not have incomplete type. + // + // This is also C++ [dcl.fct]p6. + if (!Param->isInvalidDecl() && + RequireCompleteType(Param->getLocation(), Param->getType(), + diag::err_typecheck_decl_incomplete_type)) { + Param->setInvalidDecl(); + HasInvalidParm = true; + } + + // C99 6.9.1p5: If the declarator includes a parameter type list, the + // declaration of each parameter shall include an identifier. + if (CheckParameterNames && + Param->getIdentifier() == 0 && + !Param->isImplicit() && + !getLangOpts().CPlusPlus) + Diag(Param->getLocation(), diag::err_parameter_name_omitted); + + // C99 6.7.5.3p12: + // If the function declarator is not part of a definition of that + // function, parameters may have incomplete type and may use the [*] + // notation in their sequences of declarator specifiers to specify + // variable length array types. + QualType PType = Param->getOriginalType(); + if (const ArrayType *AT = Context.getAsArrayType(PType)) { + if (AT->getSizeModifier() == ArrayType::Star) { + // FIXME: This diagnosic should point the the '[*]' if source-location + // information is added for it. + Diag(Param->getLocation(), diag::err_array_star_in_function_definition); + } + } + } + + return HasInvalidParm; +} + +/// CheckCastAlign - Implements -Wcast-align, which warns when a +/// pointer cast increases the alignment requirements. +void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { + // This is actually a lot of work to potentially be doing on every + // cast; don't do it if we're ignoring -Wcast_align (as is the default). + if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, + TRange.getBegin()) + == DiagnosticsEngine::Ignored) + return; + + // Ignore dependent types. + if (T->isDependentType() || Op->getType()->isDependentType()) + return; + + // Require that the destination be a pointer type. + const PointerType *DestPtr = T->getAs<PointerType>(); + if (!DestPtr) return; + + // If the destination has alignment 1, we're done. + QualType DestPointee = DestPtr->getPointeeType(); + if (DestPointee->isIncompleteType()) return; + CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); + if (DestAlign.isOne()) return; + + // Require that the source be a pointer type. + const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); + if (!SrcPtr) return; + QualType SrcPointee = SrcPtr->getPointeeType(); + + // Whitelist casts from cv void*. We already implicitly + // whitelisted casts to cv void*, since they have alignment 1. + // Also whitelist casts involving incomplete types, which implicitly + // includes 'void'. + if (SrcPointee->isIncompleteType()) return; + + CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); + if (SrcAlign >= DestAlign) return; + + Diag(TRange.getBegin(), diag::warn_cast_align) + << Op->getType() << T + << static_cast<unsigned>(SrcAlign.getQuantity()) + << static_cast<unsigned>(DestAlign.getQuantity()) + << TRange << Op->getSourceRange(); +} + +static const Type* getElementType(const Expr *BaseExpr) { + const Type* EltType = BaseExpr->getType().getTypePtr(); + if (EltType->isAnyPointerType()) + return EltType->getPointeeType().getTypePtr(); + else if (EltType->isArrayType()) + return EltType->getBaseElementTypeUnsafe(); + return EltType; +} + +/// \brief Check whether this array fits the idiom of a size-one tail padded +/// array member of a struct. +/// +/// We avoid emitting out-of-bounds access warnings for such arrays as they are +/// commonly used to emulate flexible arrays in C89 code. +static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, + const NamedDecl *ND) { + if (Size != 1 || !ND) return false; + + const FieldDecl *FD = dyn_cast<FieldDecl>(ND); + if (!FD) return false; + + // Don't consider sizes resulting from macro expansions or template argument + // substitution to form C89 tail-padded arrays. + ConstantArrayTypeLoc TL = + cast<ConstantArrayTypeLoc>(FD->getTypeSourceInfo()->getTypeLoc()); + const Expr *SizeExpr = dyn_cast<IntegerLiteral>(TL.getSizeExpr()); + if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) + return false; + + const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); + if (!RD) return false; + if (RD->isUnion()) return false; + if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { + if (!CRD->isStandardLayout()) return false; + } + + // See if this is the last field decl in the record. + const Decl *D = FD; + while ((D = D->getNextDeclInContext())) + if (isa<FieldDecl>(D)) + return false; + return true; +} + +void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, + const ArraySubscriptExpr *ASE, + bool AllowOnePastEnd, bool IndexNegated) { + IndexExpr = IndexExpr->IgnoreParenImpCasts(); + if (IndexExpr->isValueDependent()) + return; + + const Type *EffectiveType = getElementType(BaseExpr); + BaseExpr = BaseExpr->IgnoreParenCasts(); + const ConstantArrayType *ArrayTy = + Context.getAsConstantArrayType(BaseExpr->getType()); + if (!ArrayTy) + return; + + llvm::APSInt index; + if (!IndexExpr->EvaluateAsInt(index, Context)) + return; + if (IndexNegated) + index = -index; + + const NamedDecl *ND = NULL; + if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) + ND = dyn_cast<NamedDecl>(DRE->getDecl()); + if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) + ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); + + if (index.isUnsigned() || !index.isNegative()) { + llvm::APInt size = ArrayTy->getSize(); + if (!size.isStrictlyPositive()) + return; + + const Type* BaseType = getElementType(BaseExpr); + if (BaseType != EffectiveType) { + // Make sure we're comparing apples to apples when comparing index to size + uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); + uint64_t array_typesize = Context.getTypeSize(BaseType); + // Handle ptrarith_typesize being zero, such as when casting to void* + if (!ptrarith_typesize) ptrarith_typesize = 1; + if (ptrarith_typesize != array_typesize) { + // There's a cast to a different size type involved + uint64_t ratio = array_typesize / ptrarith_typesize; + // TODO: Be smarter about handling cases where array_typesize is not a + // multiple of ptrarith_typesize + if (ptrarith_typesize * ratio == array_typesize) + size *= llvm::APInt(size.getBitWidth(), ratio); + } + } + + if (size.getBitWidth() > index.getBitWidth()) + index = index.zext(size.getBitWidth()); + else if (size.getBitWidth() < index.getBitWidth()) + size = size.zext(index.getBitWidth()); + + // For array subscripting the index must be less than size, but for pointer + // arithmetic also allow the index (offset) to be equal to size since + // computing the next address after the end of the array is legal and + // commonly done e.g. in C++ iterators and range-based for loops. + if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) + return; + + // Also don't warn for arrays of size 1 which are members of some + // structure. These are often used to approximate flexible arrays in C89 + // code. + if (IsTailPaddedMemberArray(*this, size, ND)) + return; + + // Suppress the warning if the subscript expression (as identified by the + // ']' location) and the index expression are both from macro expansions + // within a system header. + if (ASE) { + SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( + ASE->getRBracketLoc()); + if (SourceMgr.isInSystemHeader(RBracketLoc)) { + SourceLocation IndexLoc = SourceMgr.getSpellingLoc( + IndexExpr->getLocStart()); + if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) + return; + } + } + + unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; + if (ASE) + DiagID = diag::warn_array_index_exceeds_bounds; + + DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, + PDiag(DiagID) << index.toString(10, true) + << size.toString(10, true) + << (unsigned)size.getLimitedValue(~0U) + << IndexExpr->getSourceRange()); + } else { + unsigned DiagID = diag::warn_array_index_precedes_bounds; + if (!ASE) { + DiagID = diag::warn_ptr_arith_precedes_bounds; + if (index.isNegative()) index = -index; + } + + DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, + PDiag(DiagID) << index.toString(10, true) + << IndexExpr->getSourceRange()); + } + + if (!ND) { + // Try harder to find a NamedDecl to point at in the note. + while (const ArraySubscriptExpr *ASE = + dyn_cast<ArraySubscriptExpr>(BaseExpr)) + BaseExpr = ASE->getBase()->IgnoreParenCasts(); + if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) + ND = dyn_cast<NamedDecl>(DRE->getDecl()); + if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) + ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); + } + + if (ND) + DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, + PDiag(diag::note_array_index_out_of_bounds) + << ND->getDeclName()); +} + +void Sema::CheckArrayAccess(const Expr *expr) { + int AllowOnePastEnd = 0; + while (expr) { + expr = expr->IgnoreParenImpCasts(); + switch (expr->getStmtClass()) { + case Stmt::ArraySubscriptExprClass: { + const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); + CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, + AllowOnePastEnd > 0); + return; + } + case Stmt::UnaryOperatorClass: { + // Only unwrap the * and & unary operators + const UnaryOperator *UO = cast<UnaryOperator>(expr); + expr = UO->getSubExpr(); + switch (UO->getOpcode()) { + case UO_AddrOf: + AllowOnePastEnd++; + break; + case UO_Deref: + AllowOnePastEnd--; + break; + default: + return; + } + break; + } + case Stmt::ConditionalOperatorClass: { + const ConditionalOperator *cond = cast<ConditionalOperator>(expr); + if (const Expr *lhs = cond->getLHS()) + CheckArrayAccess(lhs); + if (const Expr *rhs = cond->getRHS()) + CheckArrayAccess(rhs); + return; + } + default: + return; + } + } +} + +//===--- CHECK: Objective-C retain cycles ----------------------------------// + +namespace { + struct RetainCycleOwner { + RetainCycleOwner() : Variable(0), Indirect(false) {} + VarDecl *Variable; + SourceRange Range; + SourceLocation Loc; + bool Indirect; + + void setLocsFrom(Expr *e) { + Loc = e->getExprLoc(); + Range = e->getSourceRange(); + } + }; +} + +/// Consider whether capturing the given variable can possibly lead to +/// a retain cycle. +static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { + // In ARC, it's captured strongly iff the variable has __strong + // lifetime. In MRR, it's captured strongly if the variable is + // __block and has an appropriate type. + if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) + return false; + + owner.Variable = var; + owner.setLocsFrom(ref); + return true; +} + +static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { + while (true) { + e = e->IgnoreParens(); + if (CastExpr *cast = dyn_cast<CastExpr>(e)) { + switch (cast->getCastKind()) { + case CK_BitCast: + case CK_LValueBitCast: + case CK_LValueToRValue: + case CK_ARCReclaimReturnedObject: + e = cast->getSubExpr(); + continue; + + default: + return false; + } + } + + if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { + ObjCIvarDecl *ivar = ref->getDecl(); + if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) + return false; + + // Try to find a retain cycle in the base. + if (!findRetainCycleOwner(S, ref->getBase(), owner)) + return false; + + if (ref->isFreeIvar()) owner.setLocsFrom(ref); + owner.Indirect = true; + return true; + } + + if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { + VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); + if (!var) return false; + return considerVariable(var, ref, owner); + } + + if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { + if (member->isArrow()) return false; + + // Don't count this as an indirect ownership. + e = member->getBase(); + continue; + } + + if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { + // Only pay attention to pseudo-objects on property references. + ObjCPropertyRefExpr *pre + = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() + ->IgnoreParens()); + if (!pre) return false; + if (pre->isImplicitProperty()) return false; + ObjCPropertyDecl *property = pre->getExplicitProperty(); + if (!property->isRetaining() && + !(property->getPropertyIvarDecl() && + property->getPropertyIvarDecl()->getType() + .getObjCLifetime() == Qualifiers::OCL_Strong)) + return false; + + owner.Indirect = true; + if (pre->isSuperReceiver()) { + owner.Variable = S.getCurMethodDecl()->getSelfDecl(); + if (!owner.Variable) + return false; + owner.Loc = pre->getLocation(); + owner.Range = pre->getSourceRange(); + return true; + } + e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) + ->getSourceExpr()); + continue; + } + + // Array ivars? + + return false; + } +} + +namespace { + struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { + FindCaptureVisitor(ASTContext &Context, VarDecl *variable) + : EvaluatedExprVisitor<FindCaptureVisitor>(Context), + Variable(variable), Capturer(0) {} + + VarDecl *Variable; + Expr *Capturer; + + void VisitDeclRefExpr(DeclRefExpr *ref) { + if (ref->getDecl() == Variable && !Capturer) + Capturer = ref; + } + + void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { + if (Capturer) return; + Visit(ref->getBase()); + if (Capturer && ref->isFreeIvar()) + Capturer = ref; + } + + void VisitBlockExpr(BlockExpr *block) { + // Look inside nested blocks + if (block->getBlockDecl()->capturesVariable(Variable)) + Visit(block->getBlockDecl()->getBody()); + } + }; +} + +/// Check whether the given argument is a block which captures a +/// variable. +static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { + assert(owner.Variable && owner.Loc.isValid()); + + e = e->IgnoreParenCasts(); + BlockExpr *block = dyn_cast<BlockExpr>(e); + if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) + return 0; + + FindCaptureVisitor visitor(S.Context, owner.Variable); + visitor.Visit(block->getBlockDecl()->getBody()); + return visitor.Capturer; +} + +static void diagnoseRetainCycle(Sema &S, Expr *capturer, + RetainCycleOwner &owner) { + assert(capturer); + assert(owner.Variable && owner.Loc.isValid()); + + S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) + << owner.Variable << capturer->getSourceRange(); + S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) + << owner.Indirect << owner.Range; +} + +/// Check for a keyword selector that starts with the word 'add' or +/// 'set'. +static bool isSetterLikeSelector(Selector sel) { + if (sel.isUnarySelector()) return false; + + StringRef str = sel.getNameForSlot(0); + while (!str.empty() && str.front() == '_') str = str.substr(1); + if (str.startswith("set")) + str = str.substr(3); + else if (str.startswith("add")) { + // Specially whitelist 'addOperationWithBlock:'. + if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) + return false; + str = str.substr(3); + } + else + return false; + + if (str.empty()) return true; + return !islower(str.front()); +} + +/// Check a message send to see if it's likely to cause a retain cycle. +void Sema::checkRetainCycles(ObjCMessageExpr *msg) { + // Only check instance methods whose selector looks like a setter. + if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) + return; + + // Try to find a variable that the receiver is strongly owned by. + RetainCycleOwner owner; + if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { + if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) + return; + } else { + assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); + owner.Variable = getCurMethodDecl()->getSelfDecl(); + owner.Loc = msg->getSuperLoc(); + owner.Range = msg->getSuperLoc(); + } + + // Check whether the receiver is captured by any of the arguments. + for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) + if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) + return diagnoseRetainCycle(*this, capturer, owner); +} + +/// Check a property assign to see if it's likely to cause a retain cycle. +void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { + RetainCycleOwner owner; + if (!findRetainCycleOwner(*this, receiver, owner)) + return; + + if (Expr *capturer = findCapturingExpr(*this, argument, owner)) + diagnoseRetainCycle(*this, capturer, owner); +} + +bool Sema::checkUnsafeAssigns(SourceLocation Loc, + QualType LHS, Expr *RHS) { + Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); + if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) + return false; + // strip off any implicit cast added to get to the one arc-specific + while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { + if (cast->getCastKind() == CK_ARCConsumeObject) { + Diag(Loc, diag::warn_arc_retained_assign) + << (LT == Qualifiers::OCL_ExplicitNone) + << RHS->getSourceRange(); + return true; + } + RHS = cast->getSubExpr(); + } + return false; +} + +void Sema::checkUnsafeExprAssigns(SourceLocation Loc, + Expr *LHS, Expr *RHS) { + QualType LHSType; + // PropertyRef on LHS type need be directly obtained from + // its declaration as it has a PsuedoType. + ObjCPropertyRefExpr *PRE + = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); + if (PRE && !PRE->isImplicitProperty()) { + const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); + if (PD) + LHSType = PD->getType(); + } + + if (LHSType.isNull()) + LHSType = LHS->getType(); + if (checkUnsafeAssigns(Loc, LHSType, RHS)) + return; + Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); + // FIXME. Check for other life times. + if (LT != Qualifiers::OCL_None) + return; + + if (PRE) { + if (PRE->isImplicitProperty()) + return; + const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); + if (!PD) + return; + + unsigned Attributes = PD->getPropertyAttributes(); + if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { + // when 'assign' attribute was not explicitly specified + // by user, ignore it and rely on property type itself + // for lifetime info. + unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); + if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && + LHSType->isObjCRetainableType()) + return; + + while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { + if (cast->getCastKind() == CK_ARCConsumeObject) { + Diag(Loc, diag::warn_arc_retained_property_assign) + << RHS->getSourceRange(); + return; + } + RHS = cast->getSubExpr(); + } + } + } +} + +//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// + +namespace { +bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, + SourceLocation StmtLoc, + const NullStmt *Body) { + // Do not warn if the body is a macro that expands to nothing, e.g: + // + // #define CALL(x) + // if (condition) + // CALL(0); + // + if (Body->hasLeadingEmptyMacro()) + return false; + + // Get line numbers of statement and body. + bool StmtLineInvalid; + unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, + &StmtLineInvalid); + if (StmtLineInvalid) + return false; + + bool BodyLineInvalid; + unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), + &BodyLineInvalid); + if (BodyLineInvalid) + return false; + + // Warn if null statement and body are on the same line. + if (StmtLine != BodyLine) + return false; + + return true; +} +} // Unnamed namespace + +void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, + const Stmt *Body, + unsigned DiagID) { + // Since this is a syntactic check, don't emit diagnostic for template + // instantiations, this just adds noise. + if (CurrentInstantiationScope) + return; + + // The body should be a null statement. + const NullStmt *NBody = dyn_cast<NullStmt>(Body); + if (!NBody) + return; + + // Do the usual checks. + if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) + return; + + Diag(NBody->getSemiLoc(), DiagID); + Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); +} + +void Sema::DiagnoseEmptyLoopBody(const Stmt *S, + const Stmt *PossibleBody) { + assert(!CurrentInstantiationScope); // Ensured by caller + + SourceLocation StmtLoc; + const Stmt *Body; + unsigned DiagID; + if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { + StmtLoc = FS->getRParenLoc(); + Body = FS->getBody(); + DiagID = diag::warn_empty_for_body; + } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { + StmtLoc = WS->getCond()->getSourceRange().getEnd(); + Body = WS->getBody(); + DiagID = diag::warn_empty_while_body; + } else + return; // Neither `for' nor `while'. + + // The body should be a null statement. + const NullStmt *NBody = dyn_cast<NullStmt>(Body); + if (!NBody) + return; + + // Skip expensive checks if diagnostic is disabled. + if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == + DiagnosticsEngine::Ignored) + return; + + // Do the usual checks. + if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) + return; + + // `for(...);' and `while(...);' are popular idioms, so in order to keep + // noise level low, emit diagnostics only if for/while is followed by a + // CompoundStmt, e.g.: + // for (int i = 0; i < n; i++); + // { + // a(i); + // } + // or if for/while is followed by a statement with more indentation + // than for/while itself: + // for (int i = 0; i < n; i++); + // a(i); + bool ProbableTypo = isa<CompoundStmt>(PossibleBody); + if (!ProbableTypo) { + bool BodyColInvalid; + unsigned BodyCol = SourceMgr.getPresumedColumnNumber( + PossibleBody->getLocStart(), + &BodyColInvalid); + if (BodyColInvalid) + return; + + bool StmtColInvalid; + unsigned StmtCol = SourceMgr.getPresumedColumnNumber( + S->getLocStart(), + &StmtColInvalid); + if (StmtColInvalid) + return; + + if (BodyCol > StmtCol) + ProbableTypo = true; + } + + if (ProbableTypo) { + Diag(NBody->getSemiLoc(), DiagID); + Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); + } +} |