lib/Target/Mangler.cpp - llvm - Git at Google

 //===-- 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/DerivedTypes.h"
 #include "llvm/Function.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 using namespace llvm;

 static bool isAcceptableChar(char C, bool AllowPeriod, bool AllowUTF8) {
   if ((C < 'a' || C > 'z') &&
       (C < 'A' || C > 'Z') &&
       (C < '0' || C > '9') &&
       C != '_' && C != '$' && C != '@' &&
       !(AllowPeriod && C == '.') &&
       !(AllowUTF8 && (C & 0x80)))
     return false;
   return true;
 }

 static char HexDigit(int V) {
   return V < 10 ? V+'0' : V+'A'-10;
 }

 static void MangleLetter(SmallVectorImpl<char> &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 \arg 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();
   bool AllowUTF8 = MAI.doesAllowUTF8();
   for (unsigned i = 0, e = Str.size(); i != e; ++i)
     if (!isAcceptableChar(Str[i], AllowPeriod, AllowUTF8))
       return true;
   return false;
 }

 /// appendMangledName - Add the specified string in mangled form if it uses
 /// any unusual characters.
 static void appendMangledName(SmallVectorImpl<char> &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();
   bool AllowUTF8 = MAI.doesAllowUTF8();
   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
     if (!isAcceptableChar(Str[i], AllowPeriod, AllowUTF8))
       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<char> &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<char> &OutName,
                                 const Twine &GVName, ManglerPrefixTy PrefixTy) {
   SmallString<256> TmpData;
   StringRef Name = GVName.toStringRef(TmpData);
   assert(!Name.empty() && "getNameWithPrefix requires non-empty name");

   const MCAsmInfo &MAI = Context.getAsmInfo();

   // 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));
     }

     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
       OutName.append(Prefix, Prefix+strlen(Prefix)); // Arbitrary length 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<char> &OutName,
                                      const Function *F, const TargetData &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<PointerType>(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<char> &OutName,
                                 const GlobalValue *GV,
                                 bool isImplicitlyPrivate) {
   ManglerPrefixTy PrefixTy = Mangler::Default;
   if (GV->hasPrivateLinkage() || isImplicitlyPrivate)
     PrefixTy = Mangler::Private;
   else if (GV->hasLinkerPrivateLinkage() || GV->hasLinkerPrivateWeakLinkage() ||
            GV->hasLinkerPrivateWeakDefAutoLinkage())
     PrefixTy = Mangler::LinkerPrivate;

   // If this global has a name, handle it simply.
   if (GV->hasName()) {
     getNameWithPrefix(OutName, GV->getName(), PrefixTy);
   } 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);
   }

   // If we are supposed to add a microsoft-style suffix for stdcall/fastcall,
   // add it.
   if (Context.getAsmInfo().hasMicrosoftFastStdCallMangling()) {
     if (const Function *F = dyn_cast<Function>(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, TD);
     }
   }
 }

 /// getSymbol - Return the MCSymbol for the specified global value.  This
 /// symbol is the main label that is the address of the global.
 MCSymbol *Mangler::getSymbol(const GlobalValue *GV) {
   SmallString<60> NameStr;
   getNameWithPrefix(NameStr, GV, false);
   return Context.GetOrCreateSymbol(NameStr.str());
 }
	//===-- 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/DerivedTypes.h"
	#include "llvm/Function.h"
	#include "llvm/Target/TargetData.h"
	#include "llvm/MC/MCAsmInfo.h"
	#include "llvm/MC/MCContext.h"
	#include "llvm/Support/raw_ostream.h"
	#include "llvm/ADT/SmallString.h"
	#include "llvm/ADT/Twine.h"
	using namespace llvm;

	static bool isAcceptableChar(char C, bool AllowPeriod, bool AllowUTF8) {
	if ((C < 'a' \|\| C > 'z') &&
	(C < 'A' \|\| C > 'Z') &&
	(C < '0' \|\| C > '9') &&
	C != '_' && C != '$' && C != '@' &&
	!(AllowPeriod && C == '.') &&
	!(AllowUTF8 && (C & 0x80)))
	return false;
	return true;
	}

	static char HexDigit(int V) {
	return V < 10 ? V+'0' : V+'A'-10;
	}

	static void MangleLetter(SmallVectorImpl<char> &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 \arg 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();
	bool AllowUTF8 = MAI.doesAllowUTF8();
	for (unsigned i = 0, e = Str.size(); i != e; ++i)
	if (!isAcceptableChar(Str[i], AllowPeriod, AllowUTF8))
	return true;
	return false;
	}

	/// appendMangledName - Add the specified string in mangled form if it uses
	/// any unusual characters.
	static void appendMangledName(SmallVectorImpl<char> &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();
	bool AllowUTF8 = MAI.doesAllowUTF8();
	for (unsigned i = 0, e = Str.size(); i != e; ++i) {
	if (!isAcceptableChar(Str[i], AllowPeriod, AllowUTF8))
	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<char> &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<char> &OutName,
	const Twine &GVName, ManglerPrefixTy PrefixTy) {
	SmallString<256> TmpData;
	StringRef Name = GVName.toStringRef(TmpData);
	assert(!Name.empty() && "getNameWithPrefix requires non-empty name");

	const MCAsmInfo &MAI = Context.getAsmInfo();

	// 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));
	}

	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
	OutName.append(Prefix, Prefix+strlen(Prefix)); // Arbitrary length 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<char> &OutName,
	const Function *F, const TargetData &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<PointerType>(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<char> &OutName,
	const GlobalValue *GV,
	bool isImplicitlyPrivate) {
	ManglerPrefixTy PrefixTy = Mangler::Default;
	if (GV->hasPrivateLinkage() \|\| isImplicitlyPrivate)
	PrefixTy = Mangler::Private;
	else if (GV->hasLinkerPrivateLinkage() \|\| GV->hasLinkerPrivateWeakLinkage() \|\|
	GV->hasLinkerPrivateWeakDefAutoLinkage())
	PrefixTy = Mangler::LinkerPrivate;

	// If this global has a name, handle it simply.
	if (GV->hasName()) {
	getNameWithPrefix(OutName, GV->getName(), PrefixTy);
	} 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);
	}

	// If we are supposed to add a microsoft-style suffix for stdcall/fastcall,
	// add it.
	if (Context.getAsmInfo().hasMicrosoftFastStdCallMangling()) {
	if (const Function *F = dyn_cast<Function>(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, TD);
	}
	}
	}

	/// getSymbol - Return the MCSymbol for the specified global value. This
	/// symbol is the main label that is the address of the global.
	MCSymbol Mangler::getSymbol(const GlobalValue GV) {
	SmallString<60> NameStr;
	getNameWithPrefix(NameStr, GV, false);
	return Context.GetOrCreateSymbol(NameStr.str());
	}