lib/VMCore/Mangler.cpp

   1 //===-- Mangler.cpp - Self-contained c/asm llvm name mangler --------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file was developed by the LLVM research group and is distributed under
   6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Unified name mangler for CWriter and assembly backends.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Support/Mangler.h"
  15 #include "llvm/DerivedTypes.h"
  16 #include "llvm/Module.h"
  17 #include "llvm/ADT/StringExtras.h"
  18 using namespace llvm;
  19
  20 static char HexDigit(int V) {
  21   return V < 10 ? V+'0' : V+'A'-10;
  22 }
  23
  24 static std::string MangleLetter(unsigned char C) {
  25   char Result[] = { '_', HexDigit(C >> 4), HexDigit(C & 15), '_', 0 };
  26   return Result;
  27 }
  28
  29 /// makeNameProper - We don't want identifier names non-C-identifier characters
  30 /// in them, so mangle them as appropriate.
  31 ///
  32 std::string Mangler::makeNameProper(const std::string &X, const char *Prefix) {
  33   std::string Result;
  34   if (X.empty()) return X;  // Empty names are uniqued by the caller.
  35
  36   if (!UseQuotes) {
  37     // If X does not start with (char)1, add the prefix.
  38     std::string::const_iterator I = X.begin();
  39     if (*I != 1)
  40       Result = Prefix;
  41     else
  42       ++I;  // Skip over the marker.
  43
  44     // Mangle the first letter specially, don't allow numbers.
  45     if (*I >= '0' && *I <= '9')
  46       Result += MangleLetter(*I++);
  47
  48     for (std::string::const_iterator E = X.end(); I != E; ++I) {
  49       if (!isCharAcceptable(*I))
  50         Result += MangleLetter(*I);
  51       else
  52         Result += *I;
  53     }
  54   } else {
  55     bool NeedsQuotes = false;
  56
  57     std::string::const_iterator I = X.begin();
  58     if (*I == 1)
  59       ++I;  // Skip over the marker.
  60
  61     // If the first character is a number, we need quotes.
  62     if (*I >= '0' && *I <= '9')
  63       NeedsQuotes = true;
  64
  65     // Do an initial scan of the string, checking to see if we need quotes or
  66     // to escape a '"' or not.
  67     if (!NeedsQuotes)
  68       for (std::string::const_iterator E = X.end(); I != E; ++I)
  69         if (!isCharAcceptable(*I)) {
  70           NeedsQuotes = true;
  71           break;
  72         }
  73
  74     // In the common case, we don't need quotes.  Handle this quickly.
  75     if (!NeedsQuotes) {
  76       if (*X.begin() != 1)
  77         return Prefix+X;
  78       else
  79         return X.substr(1);
  80     }
  81
  82     // Otherwise, construct the string the expensive way.
  83     I = X.begin();
  84
  85     // If X does not start with (char)1, add the prefix.
  86     if (*I != 1)
  87       Result = Prefix;
  88     else
  89       ++I;   // Skip the marker if present.
  90
  91     for (std::string::const_iterator E = X.end(); I != E; ++I) {
  92       if (*I == '"')
  93         Result += "_QQ_";
  94       else
  95         Result += *I;
  96     }
  97     Result = '"' + Result + '"';
  98   }
  99   return Result;
 100 }
 101
 102 /// getTypeID - Return a unique ID for the specified LLVM type.
 103 ///
 104 unsigned Mangler::getTypeID(const Type *Ty) {
 105   unsigned &E = TypeMap[Ty];
 106   if (E == 0) E = ++TypeCounter;
 107   return E;
 108 }
 109
 110 std::string Mangler::getValueName(const Value *V) {
 111   if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
 112     return getValueName(GV);
 113
 114   std::string &Name = Memo[V];
 115   if (!Name.empty())
 116     return Name;       // Return the already-computed name for V.
 117
 118   // Always mangle local names.
 119   Name = "ltmp_" + utostr(Count++) + "_" + utostr(getTypeID(V->getType()));
 120   return Name;
 121 }
 122
 123
 124 std::string Mangler::getValueName(const GlobalValue *GV) {
 125   // Check to see whether we've already named V.
 126   std::string &Name = Memo[GV];
 127   if (!Name.empty())
 128     return Name;       // Return the already-computed name for V.
 129
 130   // Name mangling occurs as follows:
 131   // - If V is an intrinsic function, do not change name at all
 132   // - Otherwise, mangling occurs if global collides with existing name.
 133   if (isa<Function>(GV) && cast<Function>(GV)->getIntrinsicID()) {
 134     Name = GV->getName(); // Is an intrinsic function
 135   } else if (!GV->hasName()) {
 136     // Must mangle the global into a unique ID.
 137     unsigned TypeUniqueID = getTypeID(GV->getType());
 138     static unsigned GlobalID = 0;
 139     Name = "__unnamed_" + utostr(TypeUniqueID) + "_" + utostr(GlobalID++);
 140   } else if (!MangledGlobals.count(GV)) {
 141     Name = makeNameProper(GV->getName(), Prefix);
 142   } else {
 143     unsigned TypeUniqueID = getTypeID(GV->getType());
 144     Name = "l" + utostr(TypeUniqueID) + "_" + makeNameProper(GV->getName());
 145   }
 146
 147   return Name;
 148 }
 149
 150 void Mangler::InsertName(GlobalValue *GV,
 151                          std::map<std::string, GlobalValue*> &Names) {
 152   if (!GV->hasName())   // We must mangle unnamed globals.
 153     return;
 154
 155   // Figure out if this is already used.
 156   GlobalValue *&ExistingValue = Names[GV->getName()];
 157   if (!ExistingValue) {
 158     ExistingValue = GV;
 159   } else {
 160     // If GV is external but the existing one is static, mangle the existing one
 161     if (GV->hasExternalLinkage() && !ExistingValue->hasExternalLinkage()) {
 162       MangledGlobals.insert(ExistingValue);
 163       ExistingValue = GV;
 164     } else if (GV->hasExternalLinkage() && ExistingValue->hasExternalLinkage()&&
 165                GV->isExternal() && ExistingValue->isExternal()) {
 166       // If the two globals both have external inkage, and are both external,
 167       // don't mangle either of them, we just have some silly type mismatch.
 168     } else {
 169       // Otherwise, mangle GV
 170       MangledGlobals.insert(GV);
 171     }
 172   }
 173 }
 174
 175
 176 Mangler::Mangler(Module &M, const char *prefix)
 177   : Prefix(prefix), UseQuotes(false), Count(0), TypeCounter(0) {
 178   std::fill(AcceptableChars,
 179           AcceptableChars+sizeof(AcceptableChars)/sizeof(AcceptableChars[0]),
 180             0);
 181
 182   // Letters and numbers are acceptable.
 183   for (unsigned char X = 'a'; X <= 'z'; ++X)
 184     markCharAcceptable(X);
 185   for (unsigned char X = 'A'; X <= 'Z'; ++X)
 186     markCharAcceptable(X);
 187   for (unsigned char X = '0'; X <= '9'; ++X)
 188     markCharAcceptable(X);
 189
 190   // These chars are acceptable.
 191   markCharAcceptable('_');
 192   markCharAcceptable('$');
 193   markCharAcceptable('.');
 194
 195   // Calculate which global values have names that will collide when we throw
 196   // away type information.
 197   std::map<std::string, GlobalValue*> Names;
 198   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
 199     InsertName(I, Names);
 200   for (Module::global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
 201     InsertName(I, Names);
 202 }
 203
 204 // Cause this file to be linked in when Support/Mangler.h is #included
 205 DEFINING_FILE_FOR(Mangler)