1 //===-- Mangler.cpp - Self-contained c/asm llvm name mangler --------------===// 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 // Unified name mangler for assembly backends. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/IR/Mangler.h" 15 #include "llvm/ADT/SmallString.h" 16 #include "llvm/ADT/Twine.h" 17 #include "llvm/IR/DataLayout.h" 18 #include "llvm/IR/DerivedTypes.h" 19 #include "llvm/IR/Function.h" 20 #include "llvm/Support/raw_ostream.h" 21 using namespace llvm; 22 23 static void getNameWithPrefixx(raw_ostream &OS, const Twine &GVName, 24 Mangler::ManglerPrefixTy PrefixTy, 25 const DataLayout &DL, bool UseAt) { 26 SmallString<256> TmpData; 27 StringRef Name = GVName.toStringRef(TmpData); 28 assert(!Name.empty() && "getNameWithPrefix requires non-empty name"); 29 30 // No need to do anything special if the global has the special "do not 31 // mangle" flag in the name. 32 if (Name[0] == '\1') { 33 OS << Name.substr(1); 34 return; 35 } 36 37 if (PrefixTy == Mangler::Private) 38 OS << DL.getPrivateGlobalPrefix(); 39 else if (PrefixTy == Mangler::LinkerPrivate) 40 OS << DL.getLinkerPrivateGlobalPrefix(); 41 42 if (UseAt) { 43 OS << '@'; 44 } else { 45 char Prefix = DL.getGlobalPrefix(); 46 if (Prefix != '\0') 47 OS << Prefix; 48 } 49 50 // If this is a simple string that doesn't need escaping, just append it. 51 OS << Name; 52 } 53 54 void Mangler::getNameWithPrefix(raw_ostream &OS, const Twine &GVName, 55 ManglerPrefixTy PrefixTy) const { 56 return getNameWithPrefixx(OS, GVName, PrefixTy, *DL, false); 57 } 58 59 void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName, 60 const Twine &GVName, 61 ManglerPrefixTy PrefixTy) const { 62 raw_svector_ostream OS(OutName); 63 return getNameWithPrefix(OS, GVName, PrefixTy); 64 } 65 66 /// AddFastCallStdCallSuffix - Microsoft fastcall and stdcall functions require 67 /// a suffix on their name indicating the number of words of arguments they 68 /// take. 69 static void AddFastCallStdCallSuffix(raw_ostream &OS, const Function *F, 70 const DataLayout &TD) { 71 // Calculate arguments size total. 72 unsigned ArgWords = 0; 73 for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end(); 74 AI != AE; ++AI) { 75 // Skip arguments in registers to handle typical fastcall lowering. 76 if (F->getAttributes().hasAttribute(AI->getArgNo() + 1, Attribute::InReg)) 77 continue; 78 Type *Ty = AI->getType(); 79 // 'Dereference' type in case of byval or inalloca parameter attribute. 80 if (AI->hasByValOrInAllocaAttr()) 81 Ty = cast<PointerType>(Ty)->getElementType(); 82 // Size should be aligned to DWORD boundary 83 ArgWords += ((TD.getTypeAllocSize(Ty) + 3)/4)*4; 84 } 85 86 OS << '@' << ArgWords; 87 } 88 89 void Mangler::getNameWithPrefix(raw_ostream &OS, const GlobalValue *GV, 90 bool CannotUsePrivateLabel) const { 91 ManglerPrefixTy PrefixTy = Mangler::Default; 92 if (GV->hasPrivateLinkage()) { 93 if (CannotUsePrivateLabel) 94 PrefixTy = Mangler::LinkerPrivate; 95 else 96 PrefixTy = Mangler::Private; 97 } 98 99 if (!GV->hasName()) { 100 // Get the ID for the global, assigning a new one if we haven't got one 101 // already. 102 unsigned &ID = AnonGlobalIDs[GV]; 103 if (ID == 0) 104 ID = NextAnonGlobalID++; 105 106 // Must mangle the global into a unique ID. 107 getNameWithPrefix(OS, "__unnamed_" + Twine(ID), PrefixTy); 108 return; 109 } 110 111 StringRef Name = GV->getName(); 112 113 bool UseAt = false; 114 const Function *MSFunc = nullptr; 115 CallingConv::ID CC; 116 if (Name[0] != '\1' && DL->hasMicrosoftFastStdCallMangling()) { 117 if ((MSFunc = dyn_cast<Function>(GV))) { 118 CC = MSFunc->getCallingConv(); 119 // fastcall functions need to start with @ instead of _. 120 if (CC == CallingConv::X86_FastCall) 121 UseAt = true; 122 } 123 } 124 125 getNameWithPrefixx(OS, Name, PrefixTy, *DL, UseAt); 126 127 if (!MSFunc) 128 return; 129 130 // If we are supposed to add a microsoft-style suffix for stdcall/fastcall, 131 // add it. 132 // fastcall and stdcall functions usually need @42 at the end to specify 133 // the argument info. 134 FunctionType *FT = MSFunc->getFunctionType(); 135 if ((CC == CallingConv::X86_FastCall || CC == CallingConv::X86_StdCall) && 136 // "Pure" variadic functions do not receive @0 suffix. 137 (!FT->isVarArg() || FT->getNumParams() == 0 || 138 (FT->getNumParams() == 1 && MSFunc->hasStructRetAttr()))) 139 AddFastCallStdCallSuffix(OS, MSFunc, *DL); 140 } 141 142 void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName, 143 const GlobalValue *GV, 144 bool CannotUsePrivateLabel) const { 145 raw_svector_ostream OS(OutName); 146 getNameWithPrefix(OS, GV, CannotUsePrivateLabel); 147 } 148