From 222e2a7620e6520ffaf4fc4e69d79c18da31542e Mon Sep 17 00:00:00 2001 From: "Zancanaro; Carlo" Date: Mon, 24 Sep 2012 09:58:17 +1000 Subject: Add the clang library to the repo (with some of my changes, too). --- clang/lib/CodeGen/CGObjCRuntime.cpp | 374 ++++++++++++++++++++++++++++++++++++ 1 file changed, 374 insertions(+) create mode 100644 clang/lib/CodeGen/CGObjCRuntime.cpp (limited to 'clang/lib/CodeGen/CGObjCRuntime.cpp') diff --git a/clang/lib/CodeGen/CGObjCRuntime.cpp b/clang/lib/CodeGen/CGObjCRuntime.cpp new file mode 100644 index 0000000..9370096 --- /dev/null +++ b/clang/lib/CodeGen/CGObjCRuntime.cpp @@ -0,0 +1,374 @@ +//==- CGObjCRuntime.cpp - Interface to Shared Objective-C Runtime Features ==// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This abstract class defines the interface for Objective-C runtime-specific +// code generation. It provides some concrete helper methods for functionality +// shared between all (or most) of the Objective-C runtimes supported by clang. +// +//===----------------------------------------------------------------------===// + +#include "CGObjCRuntime.h" + +#include "CGRecordLayout.h" +#include "CodeGenModule.h" +#include "CodeGenFunction.h" +#include "CGCleanup.h" + +#include "clang/AST/RecordLayout.h" +#include "clang/AST/StmtObjC.h" + +#include "llvm/Support/CallSite.h" + +using namespace clang; +using namespace CodeGen; + +static uint64_t LookupFieldBitOffset(CodeGen::CodeGenModule &CGM, + const ObjCInterfaceDecl *OID, + const ObjCImplementationDecl *ID, + const ObjCIvarDecl *Ivar) { + const ObjCInterfaceDecl *Container = Ivar->getContainingInterface(); + + // FIXME: We should eliminate the need to have ObjCImplementationDecl passed + // in here; it should never be necessary because that should be the lexical + // decl context for the ivar. + + // If we know have an implementation (and the ivar is in it) then + // look up in the implementation layout. + const ASTRecordLayout *RL; + if (ID && declaresSameEntity(ID->getClassInterface(), Container)) + RL = &CGM.getContext().getASTObjCImplementationLayout(ID); + else + RL = &CGM.getContext().getASTObjCInterfaceLayout(Container); + + // Compute field index. + // + // FIXME: The index here is closely tied to how ASTContext::getObjCLayout is + // implemented. This should be fixed to get the information from the layout + // directly. + unsigned Index = 0; + + for (const ObjCIvarDecl *IVD = Container->all_declared_ivar_begin(); + IVD; IVD = IVD->getNextIvar()) { + if (Ivar == IVD) + break; + ++Index; + } + assert(Index < RL->getFieldCount() && "Ivar is not inside record layout!"); + + return RL->getFieldOffset(Index); +} + +uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM, + const ObjCInterfaceDecl *OID, + const ObjCIvarDecl *Ivar) { + return LookupFieldBitOffset(CGM, OID, 0, Ivar) / + CGM.getContext().getCharWidth(); +} + +uint64_t CGObjCRuntime::ComputeIvarBaseOffset(CodeGen::CodeGenModule &CGM, + const ObjCImplementationDecl *OID, + const ObjCIvarDecl *Ivar) { + return LookupFieldBitOffset(CGM, OID->getClassInterface(), OID, Ivar) / + CGM.getContext().getCharWidth(); +} + +LValue CGObjCRuntime::EmitValueForIvarAtOffset(CodeGen::CodeGenFunction &CGF, + const ObjCInterfaceDecl *OID, + llvm::Value *BaseValue, + const ObjCIvarDecl *Ivar, + unsigned CVRQualifiers, + llvm::Value *Offset) { + // Compute (type*) ( (char *) BaseValue + Offset) + llvm::Type *I8Ptr = CGF.Int8PtrTy; + QualType IvarTy = Ivar->getType(); + llvm::Type *LTy = CGF.CGM.getTypes().ConvertTypeForMem(IvarTy); + llvm::Value *V = CGF.Builder.CreateBitCast(BaseValue, I8Ptr); + V = CGF.Builder.CreateInBoundsGEP(V, Offset, "add.ptr"); + V = CGF.Builder.CreateBitCast(V, llvm::PointerType::getUnqual(LTy)); + + if (!Ivar->isBitField()) { + LValue LV = CGF.MakeNaturalAlignAddrLValue(V, IvarTy); + LV.getQuals().addCVRQualifiers(CVRQualifiers); + return LV; + } + + // We need to compute an access strategy for this bit-field. We are given the + // offset to the first byte in the bit-field, the sub-byte offset is taken + // from the original layout. We reuse the normal bit-field access strategy by + // treating this as an access to a struct where the bit-field is in byte 0, + // and adjust the containing type size as appropriate. + // + // FIXME: Note that currently we make a very conservative estimate of the + // alignment of the bit-field, because (a) it is not clear what guarantees the + // runtime makes us, and (b) we don't have a way to specify that the struct is + // at an alignment plus offset. + // + // Note, there is a subtle invariant here: we can only call this routine on + // non-synthesized ivars but we may be called for synthesized ivars. However, + // a synthesized ivar can never be a bit-field, so this is safe. + const ASTRecordLayout &RL = + CGF.CGM.getContext().getASTObjCInterfaceLayout(OID); + uint64_t TypeSizeInBits = CGF.CGM.getContext().toBits(RL.getSize()); + uint64_t FieldBitOffset = LookupFieldBitOffset(CGF.CGM, OID, 0, Ivar); + uint64_t BitOffset = FieldBitOffset % CGF.CGM.getContext().getCharWidth(); + uint64_t ContainingTypeAlign = CGF.CGM.getContext().getTargetInfo().getCharAlign(); + uint64_t ContainingTypeSize = TypeSizeInBits - (FieldBitOffset - BitOffset); + uint64_t BitFieldSize = Ivar->getBitWidthValue(CGF.getContext()); + + // Allocate a new CGBitFieldInfo object to describe this access. + // + // FIXME: This is incredibly wasteful, these should be uniqued or part of some + // layout object. However, this is blocked on other cleanups to the + // Objective-C code, so for now we just live with allocating a bunch of these + // objects. + CGBitFieldInfo *Info = new (CGF.CGM.getContext()) CGBitFieldInfo( + CGBitFieldInfo::MakeInfo(CGF.CGM.getTypes(), Ivar, BitOffset, BitFieldSize, + ContainingTypeSize, ContainingTypeAlign)); + + return LValue::MakeBitfield(V, *Info, + IvarTy.withCVRQualifiers(CVRQualifiers)); +} + +namespace { + struct CatchHandler { + const VarDecl *Variable; + const Stmt *Body; + llvm::BasicBlock *Block; + llvm::Value *TypeInfo; + }; + + struct CallObjCEndCatch : EHScopeStack::Cleanup { + CallObjCEndCatch(bool MightThrow, llvm::Value *Fn) : + MightThrow(MightThrow), Fn(Fn) {} + bool MightThrow; + llvm::Value *Fn; + + void Emit(CodeGenFunction &CGF, Flags flags) { + if (!MightThrow) { + CGF.Builder.CreateCall(Fn)->setDoesNotThrow(); + return; + } + + CGF.EmitCallOrInvoke(Fn); + } + }; +} + + +void CGObjCRuntime::EmitTryCatchStmt(CodeGenFunction &CGF, + const ObjCAtTryStmt &S, + llvm::Constant *beginCatchFn, + llvm::Constant *endCatchFn, + llvm::Constant *exceptionRethrowFn) { + // Jump destination for falling out of catch bodies. + CodeGenFunction::JumpDest Cont; + if (S.getNumCatchStmts()) + Cont = CGF.getJumpDestInCurrentScope("eh.cont"); + + CodeGenFunction::FinallyInfo FinallyInfo; + if (const ObjCAtFinallyStmt *Finally = S.getFinallyStmt()) + FinallyInfo.enter(CGF, Finally->getFinallyBody(), + beginCatchFn, endCatchFn, exceptionRethrowFn); + + SmallVector Handlers; + + // Enter the catch, if there is one. + if (S.getNumCatchStmts()) { + for (unsigned I = 0, N = S.getNumCatchStmts(); I != N; ++I) { + const ObjCAtCatchStmt *CatchStmt = S.getCatchStmt(I); + const VarDecl *CatchDecl = CatchStmt->getCatchParamDecl(); + + Handlers.push_back(CatchHandler()); + CatchHandler &Handler = Handlers.back(); + Handler.Variable = CatchDecl; + Handler.Body = CatchStmt->getCatchBody(); + Handler.Block = CGF.createBasicBlock("catch"); + + // @catch(...) always matches. + if (!CatchDecl) { + Handler.TypeInfo = 0; // catch-all + // Don't consider any other catches. + break; + } + + Handler.TypeInfo = GetEHType(CatchDecl->getType()); + } + + EHCatchScope *Catch = CGF.EHStack.pushCatch(Handlers.size()); + for (unsigned I = 0, E = Handlers.size(); I != E; ++I) + Catch->setHandler(I, Handlers[I].TypeInfo, Handlers[I].Block); + } + + // Emit the try body. + CGF.EmitStmt(S.getTryBody()); + + // Leave the try. + if (S.getNumCatchStmts()) + CGF.popCatchScope(); + + // Remember where we were. + CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP(); + + // Emit the handlers. + for (unsigned I = 0, E = Handlers.size(); I != E; ++I) { + CatchHandler &Handler = Handlers[I]; + + CGF.EmitBlock(Handler.Block); + llvm::Value *RawExn = CGF.getExceptionFromSlot(); + + // Enter the catch. + llvm::Value *Exn = RawExn; + if (beginCatchFn) { + Exn = CGF.Builder.CreateCall(beginCatchFn, RawExn, "exn.adjusted"); + cast(Exn)->setDoesNotThrow(); + } + + CodeGenFunction::LexicalScope cleanups(CGF, Handler.Body->getSourceRange()); + + if (endCatchFn) { + // Add a cleanup to leave the catch. + bool EndCatchMightThrow = (Handler.Variable == 0); + + CGF.EHStack.pushCleanup(NormalAndEHCleanup, + EndCatchMightThrow, + endCatchFn); + } + + // Bind the catch parameter if it exists. + if (const VarDecl *CatchParam = Handler.Variable) { + llvm::Type *CatchType = CGF.ConvertType(CatchParam->getType()); + llvm::Value *CastExn = CGF.Builder.CreateBitCast(Exn, CatchType); + + CGF.EmitAutoVarDecl(*CatchParam); + + llvm::Value *CatchParamAddr = CGF.GetAddrOfLocalVar(CatchParam); + + switch (CatchParam->getType().getQualifiers().getObjCLifetime()) { + case Qualifiers::OCL_Strong: + CastExn = CGF.EmitARCRetainNonBlock(CastExn); + // fallthrough + + case Qualifiers::OCL_None: + case Qualifiers::OCL_ExplicitNone: + case Qualifiers::OCL_Autoreleasing: + CGF.Builder.CreateStore(CastExn, CatchParamAddr); + break; + + case Qualifiers::OCL_Weak: + CGF.EmitARCInitWeak(CatchParamAddr, CastExn); + break; + } + } + + CGF.ObjCEHValueStack.push_back(Exn); + CGF.EmitStmt(Handler.Body); + CGF.ObjCEHValueStack.pop_back(); + + // Leave any cleanups associated with the catch. + cleanups.ForceCleanup(); + + CGF.EmitBranchThroughCleanup(Cont); + } + + // Go back to the try-statement fallthrough. + CGF.Builder.restoreIP(SavedIP); + + // Pop out of the finally. + if (S.getFinallyStmt()) + FinallyInfo.exit(CGF); + + if (Cont.isValid()) + CGF.EmitBlock(Cont.getBlock()); +} + +namespace { + struct CallSyncExit : EHScopeStack::Cleanup { + llvm::Value *SyncExitFn; + llvm::Value *SyncArg; + CallSyncExit(llvm::Value *SyncExitFn, llvm::Value *SyncArg) + : SyncExitFn(SyncExitFn), SyncArg(SyncArg) {} + + void Emit(CodeGenFunction &CGF, Flags flags) { + CGF.Builder.CreateCall(SyncExitFn, SyncArg)->setDoesNotThrow(); + } + }; +} + +void CGObjCRuntime::EmitAtSynchronizedStmt(CodeGenFunction &CGF, + const ObjCAtSynchronizedStmt &S, + llvm::Function *syncEnterFn, + llvm::Function *syncExitFn) { + CodeGenFunction::RunCleanupsScope cleanups(CGF); + + // Evaluate the lock operand. This is guaranteed to dominate the + // ARC release and lock-release cleanups. + const Expr *lockExpr = S.getSynchExpr(); + llvm::Value *lock; + if (CGF.getLangOpts().ObjCAutoRefCount) { + lock = CGF.EmitARCRetainScalarExpr(lockExpr); + lock = CGF.EmitObjCConsumeObject(lockExpr->getType(), lock); + } else { + lock = CGF.EmitScalarExpr(lockExpr); + } + lock = CGF.Builder.CreateBitCast(lock, CGF.VoidPtrTy); + + // Acquire the lock. + CGF.Builder.CreateCall(syncEnterFn, lock)->setDoesNotThrow(); + + // Register an all-paths cleanup to release the lock. + CGF.EHStack.pushCleanup(NormalAndEHCleanup, syncExitFn, lock); + + // Emit the body of the statement. + CGF.EmitStmt(S.getSynchBody()); +} + +/// Compute the pointer-to-function type to which a message send +/// should be casted in order to correctly call the given method +/// with the given arguments. +/// +/// \param method - may be null +/// \param resultType - the result type to use if there's no method +/// \param argInfo - the actual arguments, including implicit ones +CGObjCRuntime::MessageSendInfo +CGObjCRuntime::getMessageSendInfo(const ObjCMethodDecl *method, + QualType resultType, + CallArgList &callArgs) { + // If there's a method, use information from that. + if (method) { + const CGFunctionInfo &signature = + CGM.getTypes().arrangeObjCMessageSendSignature(method, callArgs[0].Ty); + + llvm::PointerType *signatureType = + CGM.getTypes().GetFunctionType(signature)->getPointerTo(); + + // If that's not variadic, there's no need to recompute the ABI + // arrangement. + if (!signature.isVariadic()) + return MessageSendInfo(signature, signatureType); + + // Otherwise, there is. + FunctionType::ExtInfo einfo = signature.getExtInfo(); + const CGFunctionInfo &argsInfo = + CGM.getTypes().arrangeFunctionCall(resultType, callArgs, einfo, + signature.getRequiredArgs()); + + return MessageSendInfo(argsInfo, signatureType); + } + + // There's no method; just use a default CC. + const CGFunctionInfo &argsInfo = + CGM.getTypes().arrangeFunctionCall(resultType, callArgs, + FunctionType::ExtInfo(), + RequiredArgs::All); + + // Derive the signature to call from that. + llvm::PointerType *signatureType = + CGM.getTypes().GetFunctionType(argsInfo)->getPointerTo(); + return MessageSendInfo(argsInfo, signatureType); +} -- cgit v1.2.3