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+//===---- TargetInfo.h - Encapsulate target details -------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// These classes wrap the information about a call or function
+// definition used to handle ABI compliancy.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CLANG_CODEGEN_TARGETINFO_H
+#define CLANG_CODEGEN_TARGETINFO_H
+
+#include "clang/Basic/LLVM.h"
+#include "clang/AST/Type.h"
+#include "llvm/ADT/StringRef.h"
+
+namespace llvm {
+ class GlobalValue;
+ class Type;
+ class Value;
+}
+
+namespace clang {
+ class ABIInfo;
+ class Decl;
+
+ namespace CodeGen {
+ class CallArgList;
+ class CodeGenModule;
+ class CodeGenFunction;
+ class CGFunctionInfo;
+ }
+
+ /// TargetCodeGenInfo - This class organizes various target-specific
+ /// codegeneration issues, like target-specific attributes, builtins and so
+ /// on.
+ class TargetCodeGenInfo {
+ ABIInfo *Info;
+ public:
+ // WARNING: Acquires the ownership of ABIInfo.
+ TargetCodeGenInfo(ABIInfo *info = 0):Info(info) { }
+ virtual ~TargetCodeGenInfo();
+
+ /// getABIInfo() - Returns ABI info helper for the target.
+ const ABIInfo& getABIInfo() const { return *Info; }
+
+ /// SetTargetAttributes - Provides a convenient hook to handle extra
+ /// target-specific attributes for the given global.
+ virtual void SetTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
+ CodeGen::CodeGenModule &M) const { }
+
+ /// Determines the size of struct _Unwind_Exception on this platform,
+ /// in 8-bit units. The Itanium ABI defines this as:
+ /// struct _Unwind_Exception {
+ /// uint64 exception_class;
+ /// _Unwind_Exception_Cleanup_Fn exception_cleanup;
+ /// uint64 private_1;
+ /// uint64 private_2;
+ /// };
+ virtual unsigned getSizeOfUnwindException() const;
+
+ /// Controls whether __builtin_extend_pointer should sign-extend
+ /// pointers to uint64_t or zero-extend them (the default). Has
+ /// no effect for targets:
+ /// - that have 64-bit pointers, or
+ /// - that cannot address through registers larger than pointers, or
+ /// - that implicitly ignore/truncate the top bits when addressing
+ /// through such registers.
+ virtual bool extendPointerWithSExt() const { return false; }
+
+ /// Determines the DWARF register number for the stack pointer, for
+ /// exception-handling purposes. Implements __builtin_dwarf_sp_column.
+ ///
+ /// Returns -1 if the operation is unsupported by this target.
+ virtual int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const {
+ return -1;
+ }
+
+ /// Initializes the given DWARF EH register-size table, a char*.
+ /// Implements __builtin_init_dwarf_reg_size_table.
+ ///
+ /// Returns true if the operation is unsupported by this target.
+ virtual bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
+ llvm::Value *Address) const {
+ return true;
+ }
+
+ /// Performs the code-generation required to convert a return
+ /// address as stored by the system into the actual address of the
+ /// next instruction that will be executed.
+ ///
+ /// Used by __builtin_extract_return_addr().
+ virtual llvm::Value *decodeReturnAddress(CodeGen::CodeGenFunction &CGF,
+ llvm::Value *Address) const {
+ return Address;
+ }
+
+ /// Performs the code-generation required to convert the address
+ /// of an instruction into a return address suitable for storage
+ /// by the system in a return slot.
+ ///
+ /// Used by __builtin_frob_return_addr().
+ virtual llvm::Value *encodeReturnAddress(CodeGen::CodeGenFunction &CGF,
+ llvm::Value *Address) const {
+ return Address;
+ }
+
+ virtual llvm::Type* adjustInlineAsmType(CodeGen::CodeGenFunction &CGF,
+ StringRef Constraint,
+ llvm::Type* Ty) const {
+ return Ty;
+ }
+
+ /// Retrieve the address of a function to call immediately before
+ /// calling objc_retainAutoreleasedReturnValue. The
+ /// implementation of objc_autoreleaseReturnValue sniffs the
+ /// instruction stream following its return address to decide
+ /// whether it's a call to objc_retainAutoreleasedReturnValue.
+ /// This can be prohibitively expensive, depending on the
+ /// relocation model, and so on some targets it instead sniffs for
+ /// a particular instruction sequence. This functions returns
+ /// that instruction sequence in inline assembly, which will be
+ /// empty if none is required.
+ virtual StringRef getARCRetainAutoreleasedReturnValueMarker() const {
+ return "";
+ }
+
+ /// Determine whether a call to an unprototyped functions under
+ /// the given calling convention should use the variadic
+ /// convention or the non-variadic convention.
+ ///
+ /// There's a good reason to make a platform's variadic calling
+ /// convention be different from its non-variadic calling
+ /// convention: the non-variadic arguments can be passed in
+ /// registers (better for performance), and the variadic arguments
+ /// can be passed on the stack (also better for performance). If
+ /// this is done, however, unprototyped functions *must* use the
+ /// non-variadic convention, because C99 states that a call
+ /// through an unprototyped function type must succeed if the
+ /// function was defined with a non-variadic prototype with
+ /// compatible parameters. Therefore, splitting the conventions
+ /// makes it impossible to call a variadic function through an
+ /// unprototyped type. Since function prototypes came out in the
+ /// late 1970s, this is probably an acceptable trade-off.
+ /// Nonetheless, not all platforms are willing to make it, and in
+ /// particularly x86-64 bends over backwards to make the
+ /// conventions compatible.
+ ///
+ /// The default is false. This is correct whenever:
+ /// - the conventions are exactly the same, because it does not
+ /// matter and the resulting IR will be somewhat prettier in
+ /// certain cases; or
+ /// - the conventions are substantively different in how they pass
+ /// arguments, because in this case using the variadic convention
+ /// will lead to C99 violations.
+ /// It is not necessarily correct when arguments are passed in the
+ /// same way and some out-of-band information is passed for the
+ /// benefit of variadic callees, as is the case for x86-64.
+ /// In this case the ABI should be consulted.
+ virtual bool isNoProtoCallVariadic(const CodeGen::CallArgList &args,
+ const FunctionNoProtoType *fnType) const;
+ };
+}
+
+#endif // CLANG_CODEGEN_TARGETINFO_H