//===-- Mangler.cpp - Self-contained c/asm llvm name mangler --------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // Unified name mangler for assembly backends. // //===----------------------------------------------------------------------===// #include "llvm/Target/Mangler.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/Twine.h" #include "llvm/IR/DataLayout.h" #include "llvm/IR/DerivedTypes.h" #include "llvm/IR/Function.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCContext.h" #include "llvm/Target/TargetMachine.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; static bool isAcceptableChar(char C, bool AllowPeriod) { if ((C < 'a' || C > 'z') && (C < 'A' || C > 'Z') && (C < '0' || C > '9') && C != '_' && C != '$' && C != '@' && !(AllowPeriod && C == '.') && !(C & 0x80)) return false; return true; } static char HexDigit(int V) { return V < 10 ? V+'0' : V+'A'-10; } static void MangleLetter(SmallVectorImpl &OutName, unsigned char C) { OutName.push_back('_'); OutName.push_back(HexDigit(C >> 4)); OutName.push_back(HexDigit(C & 15)); OutName.push_back('_'); } /// NameNeedsEscaping - Return true if the identifier \p Str needs quotes /// for this assembler. static bool NameNeedsEscaping(StringRef Str, const MCAsmInfo *MAI) { assert(!Str.empty() && "Cannot create an empty MCSymbol"); // If the first character is a number and the target does not allow this, we // need quotes. if (!MAI->doesAllowNameToStartWithDigit() && Str[0] >= '0' && Str[0] <= '9') return true; // If any of the characters in the string is an unacceptable character, force // quotes. bool AllowPeriod = MAI->doesAllowPeriodsInName(); for (unsigned i = 0, e = Str.size(); i != e; ++i) if (!isAcceptableChar(Str[i], AllowPeriod)) return true; return false; } /// appendMangledName - Add the specified string in mangled form if it uses /// any unusual characters. static void appendMangledName(SmallVectorImpl &OutName, StringRef Str, const MCAsmInfo *MAI) { // The first character is not allowed to be a number unless the target // explicitly allows it. if (!MAI->doesAllowNameToStartWithDigit() && Str[0] >= '0' && Str[0] <= '9') { MangleLetter(OutName, Str[0]); Str = Str.substr(1); } bool AllowPeriod = MAI->doesAllowPeriodsInName(); for (unsigned i = 0, e = Str.size(); i != e; ++i) { if (!isAcceptableChar(Str[i], AllowPeriod)) MangleLetter(OutName, Str[i]); else OutName.push_back(Str[i]); } } /// appendMangledQuotedName - On systems that support quoted symbols, we still /// have to escape some (obscure) characters like " and \n which would break the /// assembler's lexing. static void appendMangledQuotedName(SmallVectorImpl &OutName, StringRef Str) { for (unsigned i = 0, e = Str.size(); i != e; ++i) { if (Str[i] == '"' || Str[i] == '\n') MangleLetter(OutName, Str[i]); else OutName.push_back(Str[i]); } } /// getNameWithPrefix - Fill OutName with the name of the appropriate prefix /// and the specified name as the global variable name. GVName must not be /// empty. void Mangler::getNameWithPrefix(SmallVectorImpl &OutName, const Twine &GVName, ManglerPrefixTy PrefixTy, bool UseGlobalPrefix) { SmallString<256> TmpData; StringRef Name = GVName.toStringRef(TmpData); assert(!Name.empty() && "getNameWithPrefix requires non-empty name"); const MCAsmInfo *MAI = TM->getMCAsmInfo(); // If the global name is not led with \1, add the appropriate prefixes. if (Name[0] == '\1') { Name = Name.substr(1); } else { if (PrefixTy == Mangler::Private) { const char *Prefix = MAI->getPrivateGlobalPrefix(); OutName.append(Prefix, Prefix+strlen(Prefix)); } else if (PrefixTy == Mangler::LinkerPrivate) { const char *Prefix = MAI->getLinkerPrivateGlobalPrefix(); OutName.append(Prefix, Prefix+strlen(Prefix)); } if (UseGlobalPrefix) { const char *Prefix = MAI->getGlobalPrefix(); if (Prefix[0] == 0) ; // Common noop, no prefix. else if (Prefix[1] == 0) OutName.push_back(Prefix[0]); // Common, one character prefix. else // Arbitrary length prefix. OutName.append(Prefix, Prefix+strlen(Prefix)); } } // If this is a simple string that doesn't need escaping, just append it. if (!NameNeedsEscaping(Name, MAI) || // If quotes are supported, they can be used unless the string contains // a quote or newline. (MAI->doesAllowQuotesInName() && Name.find_first_of("\n\"") == StringRef::npos)) { OutName.append(Name.begin(), Name.end()); return; } // On systems that do not allow quoted names, we need to mangle most // strange characters. if (!MAI->doesAllowQuotesInName()) return appendMangledName(OutName, Name, MAI); // Okay, the system allows quoted strings. We can quote most anything, the // only characters that need escaping are " and \n. assert(Name.find_first_of("\n\"") != StringRef::npos); return appendMangledQuotedName(OutName, Name); } /// AddFastCallStdCallSuffix - Microsoft fastcall and stdcall functions require /// a suffix on their name indicating the number of words of arguments they /// take. static void AddFastCallStdCallSuffix(SmallVectorImpl &OutName, const Function *F, const DataLayout &TD) { // Calculate arguments size total. unsigned ArgWords = 0; for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end(); AI != AE; ++AI) { Type *Ty = AI->getType(); // 'Dereference' type in case of byval parameter attribute if (AI->hasByValAttr()) Ty = cast(Ty)->getElementType(); // Size should be aligned to DWORD boundary ArgWords += ((TD.getTypeAllocSize(Ty) + 3)/4)*4; } raw_svector_ostream(OutName) << '@' << ArgWords; } /// getNameWithPrefix - Fill OutName with the name of the appropriate prefix /// and the specified global variable's name. If the global variable doesn't /// have a name, this fills in a unique name for the global. void Mangler::getNameWithPrefix(SmallVectorImpl &OutName, const GlobalValue *GV, bool isImplicitlyPrivate, bool UseGlobalPrefix) { ManglerPrefixTy PrefixTy = Mangler::Default; if (GV->hasPrivateLinkage() || isImplicitlyPrivate) PrefixTy = Mangler::Private; else if (GV->hasLinkerPrivateLinkage() || GV->hasLinkerPrivateWeakLinkage()) PrefixTy = Mangler::LinkerPrivate; // If this global has a name, handle it simply. if (GV->hasName()) { StringRef Name = GV->getName(); getNameWithPrefix(OutName, Name, PrefixTy, UseGlobalPrefix); // No need to do anything else if the global has the special "do not mangle" // flag in the name. if (Name[0] == 1) return; } else { // Get the ID for the global, assigning a new one if we haven't got one // already. unsigned &ID = AnonGlobalIDs[GV]; if (ID == 0) ID = NextAnonGlobalID++; // Must mangle the global into a unique ID. getNameWithPrefix(OutName, "__unnamed_" + Twine(ID), PrefixTy, UseGlobalPrefix); } // If we are supposed to add a microsoft-style suffix for stdcall/fastcall, // add it. if (TM->getMCAsmInfo()->hasMicrosoftFastStdCallMangling()) { if (const Function *F = dyn_cast(GV)) { CallingConv::ID CC = F->getCallingConv(); // fastcall functions need to start with @. // FIXME: This logic seems unlikely to be right. if (CC == CallingConv::X86_FastCall) { if (OutName[0] == '_') OutName[0] = '@'; else OutName.insert(OutName.begin(), '@'); } // fastcall and stdcall functions usually need @42 at the end to specify // the argument info. FunctionType *FT = F->getFunctionType(); if ((CC == CallingConv::X86_FastCall || CC == CallingConv::X86_StdCall) && // "Pure" variadic functions do not receive @0 suffix. (!FT->isVarArg() || FT->getNumParams() == 0 || (FT->getNumParams() == 1 && F->hasStructRetAttr()))) AddFastCallStdCallSuffix(OutName, F, *TM->getDataLayout()); } } }