1 //===-- Mangler.cpp - Self-contained c/asm llvm name mangler --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Unified name mangler for assembly backends.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Target/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/MC/MCAsmInfo.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/Target/TargetMachine.h"
23 #include "llvm/Support/raw_ostream.h"
26 static bool isAcceptableChar(char C, bool AllowPeriod) {
27 if ((C < 'a' || C > 'z') &&
28 (C < 'A' || C > 'Z') &&
29 (C < '0' || C > '9') &&
30 C != '_' && C != '$' && C != '@' &&
31 !(AllowPeriod && C == '.') &&
37 static char HexDigit(int V) {
38 return V < 10 ? V+'0' : V+'A'-10;
41 static void MangleLetter(SmallVectorImpl<char> &OutName, unsigned char C) {
42 OutName.push_back('_');
43 OutName.push_back(HexDigit(C >> 4));
44 OutName.push_back(HexDigit(C & 15));
45 OutName.push_back('_');
48 /// NameNeedsEscaping - Return true if the identifier \p Str needs quotes
49 /// for this assembler.
50 static bool NameNeedsEscaping(StringRef Str, const MCAsmInfo *MAI) {
51 assert(!Str.empty() && "Cannot create an empty MCSymbol");
53 // If the first character is a number and the target does not allow this, we
55 if (!MAI->doesAllowNameToStartWithDigit() && Str[0] >= '0' && Str[0] <= '9')
58 // If any of the characters in the string is an unacceptable character, force
60 bool AllowPeriod = MAI->doesAllowPeriodsInName();
61 for (unsigned i = 0, e = Str.size(); i != e; ++i)
62 if (!isAcceptableChar(Str[i], AllowPeriod))
67 /// appendMangledName - Add the specified string in mangled form if it uses
68 /// any unusual characters.
69 static void appendMangledName(SmallVectorImpl<char> &OutName, StringRef Str,
70 const MCAsmInfo *MAI) {
71 // The first character is not allowed to be a number unless the target
72 // explicitly allows it.
73 if (!MAI->doesAllowNameToStartWithDigit() && Str[0] >= '0' && Str[0] <= '9') {
74 MangleLetter(OutName, Str[0]);
78 bool AllowPeriod = MAI->doesAllowPeriodsInName();
79 for (unsigned i = 0, e = Str.size(); i != e; ++i) {
80 if (!isAcceptableChar(Str[i], AllowPeriod))
81 MangleLetter(OutName, Str[i]);
83 OutName.push_back(Str[i]);
88 /// appendMangledQuotedName - On systems that support quoted symbols, we still
89 /// have to escape some (obscure) characters like " and \n which would break the
90 /// assembler's lexing.
91 static void appendMangledQuotedName(SmallVectorImpl<char> &OutName,
93 for (unsigned i = 0, e = Str.size(); i != e; ++i) {
94 if (Str[i] == '"' || Str[i] == '\n')
95 MangleLetter(OutName, Str[i]);
97 OutName.push_back(Str[i]);
102 /// getNameWithPrefix - Fill OutName with the name of the appropriate prefix
103 /// and the specified name as the global variable name. GVName must not be
105 void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
106 const Twine &GVName, ManglerPrefixTy PrefixTy,
107 bool UseGlobalPrefix) {
108 SmallString<256> TmpData;
109 StringRef Name = GVName.toStringRef(TmpData);
110 assert(!Name.empty() && "getNameWithPrefix requires non-empty name");
112 const MCAsmInfo *MAI = TM->getMCAsmInfo();
114 // If the global name is not led with \1, add the appropriate prefixes.
115 if (Name[0] == '\1') {
116 Name = Name.substr(1);
118 if (PrefixTy == Mangler::Private) {
119 const char *Prefix = MAI->getPrivateGlobalPrefix();
120 OutName.append(Prefix, Prefix+strlen(Prefix));
121 } else if (PrefixTy == Mangler::LinkerPrivate) {
122 const char *Prefix = MAI->getLinkerPrivateGlobalPrefix();
123 OutName.append(Prefix, Prefix+strlen(Prefix));
126 if (UseGlobalPrefix) {
127 const char *Prefix = MAI->getGlobalPrefix();
129 ; // Common noop, no prefix.
130 else if (Prefix[1] == 0)
131 OutName.push_back(Prefix[0]); // Common, one character prefix.
133 // Arbitrary length prefix.
134 OutName.append(Prefix, Prefix+strlen(Prefix));
138 // If this is a simple string that doesn't need escaping, just append it.
139 if (!NameNeedsEscaping(Name, MAI) ||
140 // If quotes are supported, they can be used unless the string contains
141 // a quote or newline.
142 (MAI->doesAllowQuotesInName() &&
143 Name.find_first_of("\n\"") == StringRef::npos)) {
144 OutName.append(Name.begin(), Name.end());
148 // On systems that do not allow quoted names, we need to mangle most
149 // strange characters.
150 if (!MAI->doesAllowQuotesInName())
151 return appendMangledName(OutName, Name, MAI);
153 // Okay, the system allows quoted strings. We can quote most anything, the
154 // only characters that need escaping are " and \n.
155 assert(Name.find_first_of("\n\"") != StringRef::npos);
156 return appendMangledQuotedName(OutName, Name);
159 /// AddFastCallStdCallSuffix - Microsoft fastcall and stdcall functions require
160 /// a suffix on their name indicating the number of words of arguments they
162 static void AddFastCallStdCallSuffix(SmallVectorImpl<char> &OutName,
163 const Function *F, const DataLayout &TD) {
164 // Calculate arguments size total.
165 unsigned ArgWords = 0;
166 for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
168 Type *Ty = AI->getType();
169 // 'Dereference' type in case of byval parameter attribute
170 if (AI->hasByValAttr())
171 Ty = cast<PointerType>(Ty)->getElementType();
172 // Size should be aligned to DWORD boundary
173 ArgWords += ((TD.getTypeAllocSize(Ty) + 3)/4)*4;
176 raw_svector_ostream(OutName) << '@' << ArgWords;
180 /// getNameWithPrefix - Fill OutName with the name of the appropriate prefix
181 /// and the specified global variable's name. If the global variable doesn't
182 /// have a name, this fills in a unique name for the global.
183 void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
184 const GlobalValue *GV, bool isImplicitlyPrivate,
185 bool UseGlobalPrefix) {
186 ManglerPrefixTy PrefixTy = Mangler::Default;
187 if (GV->hasPrivateLinkage() || isImplicitlyPrivate)
188 PrefixTy = Mangler::Private;
189 else if (GV->hasLinkerPrivateLinkage() || GV->hasLinkerPrivateWeakLinkage())
190 PrefixTy = Mangler::LinkerPrivate;
192 // If this global has a name, handle it simply.
194 StringRef Name = GV->getName();
195 getNameWithPrefix(OutName, Name, PrefixTy, UseGlobalPrefix);
196 // No need to do anything else if the global has the special "do not mangle"
201 // Get the ID for the global, assigning a new one if we haven't got one
203 unsigned &ID = AnonGlobalIDs[GV];
204 if (ID == 0) ID = NextAnonGlobalID++;
206 // Must mangle the global into a unique ID.
207 getNameWithPrefix(OutName, "__unnamed_" + Twine(ID), PrefixTy,
211 // If we are supposed to add a microsoft-style suffix for stdcall/fastcall,
213 if (TM->getMCAsmInfo()->hasMicrosoftFastStdCallMangling()) {
214 if (const Function *F = dyn_cast<Function>(GV)) {
215 CallingConv::ID CC = F->getCallingConv();
217 // fastcall functions need to start with @.
218 // FIXME: This logic seems unlikely to be right.
219 if (CC == CallingConv::X86_FastCall) {
220 if (OutName[0] == '_')
223 OutName.insert(OutName.begin(), '@');
226 // fastcall and stdcall functions usually need @42 at the end to specify
227 // the argument info.
228 FunctionType *FT = F->getFunctionType();
229 if ((CC == CallingConv::X86_FastCall || CC == CallingConv::X86_StdCall) &&
230 // "Pure" variadic functions do not receive @0 suffix.
231 (!FT->isVarArg() || FT->getNumParams() == 0 ||
232 (FT->getNumParams() == 1 && F->hasStructRetAttr())))
233 AddFastCallStdCallSuffix(OutName, F, *TM->getDataLayout());