1 //===---- TargetInfo.h - Encapsulate target details -------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // These classes wrap the information about a call or function 11 // definition used to handle ABI compliancy. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef CLANG_CODEGEN_TARGETINFO_H 16 #define CLANG_CODEGEN_TARGETINFO_H 17 18 #include "llvm/ADT/StringRef.h" 19 20 namespace llvm { 21 class GlobalValue; 22 class Type; 23 class Value; 24 } 25 26 namespace clang { 27 class ABIInfo; 28 class Decl; 29 30 namespace CodeGen { 31 class CodeGenModule; 32 class CodeGenFunction; 33 } 34 35 /// TargetCodeGenInfo - This class organizes various target-specific 36 /// codegeneration issues, like target-specific attributes, builtins and so 37 /// on. 38 class TargetCodeGenInfo { 39 ABIInfo *Info; 40 public: 41 // WARNING: Acquires the ownership of ABIInfo. Info(info)42 TargetCodeGenInfo(ABIInfo *info = 0):Info(info) { } 43 virtual ~TargetCodeGenInfo(); 44 45 /// getABIInfo() - Returns ABI info helper for the target. getABIInfo()46 const ABIInfo& getABIInfo() const { return *Info; } 47 48 /// SetTargetAttributes - Provides a convenient hook to handle extra 49 /// target-specific attributes for the given global. SetTargetAttributes(const Decl * D,llvm::GlobalValue * GV,CodeGen::CodeGenModule & M)50 virtual void SetTargetAttributes(const Decl *D, llvm::GlobalValue *GV, 51 CodeGen::CodeGenModule &M) const { } 52 53 /// Determines the size of struct _Unwind_Exception on this platform, 54 /// in 8-bit units. The Itanium ABI defines this as: 55 /// struct _Unwind_Exception { 56 /// uint64 exception_class; 57 /// _Unwind_Exception_Cleanup_Fn exception_cleanup; 58 /// uint64 private_1; 59 /// uint64 private_2; 60 /// }; getSizeOfUnwindException()61 unsigned getSizeOfUnwindException() const { return 32; } 62 63 /// Controls whether __builtin_extend_pointer should sign-extend 64 /// pointers to uint64_t or zero-extend them (the default). Has 65 /// no effect for targets: 66 /// - that have 64-bit pointers, or 67 /// - that cannot address through registers larger than pointers, or 68 /// - that implicitly ignore/truncate the top bits when addressing 69 /// through such registers. extendPointerWithSExt()70 virtual bool extendPointerWithSExt() const { return false; } 71 72 /// Determines the DWARF register number for the stack pointer, for 73 /// exception-handling purposes. Implements __builtin_dwarf_sp_column. 74 /// 75 /// Returns -1 if the operation is unsupported by this target. getDwarfEHStackPointer(CodeGen::CodeGenModule & M)76 virtual int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const { 77 return -1; 78 } 79 80 /// Initializes the given DWARF EH register-size table, a char*. 81 /// Implements __builtin_init_dwarf_reg_size_table. 82 /// 83 /// Returns true if the operation is unsupported by this target. initDwarfEHRegSizeTable(CodeGen::CodeGenFunction & CGF,llvm::Value * Address)84 virtual bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF, 85 llvm::Value *Address) const { 86 return true; 87 } 88 89 /// Performs the code-generation required to convert a return 90 /// address as stored by the system into the actual address of the 91 /// next instruction that will be executed. 92 /// 93 /// Used by __builtin_extract_return_addr(). decodeReturnAddress(CodeGen::CodeGenFunction & CGF,llvm::Value * Address)94 virtual llvm::Value *decodeReturnAddress(CodeGen::CodeGenFunction &CGF, 95 llvm::Value *Address) const { 96 return Address; 97 } 98 99 /// Performs the code-generation required to convert the address 100 /// of an instruction into a return address suitable for storage 101 /// by the system in a return slot. 102 /// 103 /// Used by __builtin_frob_return_addr(). encodeReturnAddress(CodeGen::CodeGenFunction & CGF,llvm::Value * Address)104 virtual llvm::Value *encodeReturnAddress(CodeGen::CodeGenFunction &CGF, 105 llvm::Value *Address) const { 106 return Address; 107 } 108 adjustInlineAsmType(CodeGen::CodeGenFunction & CGF,llvm::StringRef Constraint,llvm::Type * Ty)109 virtual llvm::Type* adjustInlineAsmType(CodeGen::CodeGenFunction &CGF, 110 llvm::StringRef Constraint, 111 llvm::Type* Ty) const { 112 return Ty; 113 } 114 115 /// Retrieve the address of a function to call immediately before 116 /// calling objc_retainAutoreleasedReturnValue. The 117 /// implementation of objc_autoreleaseReturnValue sniffs the 118 /// instruction stream following its return address to decide 119 /// whether it's a call to objc_retainAutoreleasedReturnValue. 120 /// This can be prohibitively expensive, depending on the 121 /// relocation model, and so on some targets it instead sniffs for 122 /// a particular instruction sequence. This functions returns 123 /// that instruction sequence in inline assembly, which will be 124 /// empty if none is required. getARCRetainAutoreleasedReturnValueMarker()125 virtual llvm::StringRef getARCRetainAutoreleasedReturnValueMarker() const { 126 return ""; 127 } 128 }; 129 } 130 131 #endif // CLANG_CODEGEN_TARGETINFO_H 132