lib/VMCore/Mangler.cpp

   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 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/STLExtras.h"
  18 #include "llvm/ADT/StringExtras.h"
  19 #include "llvm/ADT/StringMap.h"
  20 using namespace llvm;
  21
  22 static char HexDigit(int V) {
  23   return V < 10 ? V+'0' : V+'A'-10;
  24 }
  25
  26 static std::string MangleLetter(unsigned char C) {
  27   char Result[] = { '_', HexDigit(C >> 4), HexDigit(C & 15), '_', 0 };
  28   return Result;
  29 }
  30
  31 /// makeNameProper - We don't want identifier names non-C-identifier characters
  32 /// in them, so mangle them as appropriate.
  33 ///
  34 std::string Mangler::makeNameProper(const std::string &X, const char *Prefix,
  35                                     const char *PrivatePrefix) {
  36   if (X.empty()) return X;  // Empty names are uniqued by the caller.
  37
  38   // If PreserveAsmNames is set, names with asm identifiers are not modified.
  39   if (PreserveAsmNames && X[0] == 1)
  40     return X;
  41
  42   if (!UseQuotes) {
  43     std::string Result;
  44
  45     // If X does not start with (char)1, add the prefix.
  46     bool NeedPrefix = true;
  47     std::string::const_iterator I = X.begin();
  48     if (*I == 1) {
  49       NeedPrefix = false;
  50       ++I;  // Skip over the marker.
  51     }
  52
  53     // Mangle the first letter specially, don't allow numbers.
  54     if (*I >= '0' && *I <= '9')
  55       Result += MangleLetter(*I++);
  56
  57     for (std::string::const_iterator E = X.end(); I != E; ++I) {
  58       if (!isCharAcceptable(*I))
  59         Result += MangleLetter(*I);
  60       else
  61         Result += *I;
  62     }
  63
  64     if (NeedPrefix) {
  65       if (Prefix)
  66         Result = Prefix + Result;
  67       if (PrivatePrefix)
  68         Result = PrivatePrefix + Result;
  69     }
  70     return Result;
  71   }
  72
  73   bool NeedPrefix = true;
  74   bool NeedQuotes = false;
  75   std::string Result;
  76   std::string::const_iterator I = X.begin();
  77   if (*I == 1) {
  78     NeedPrefix = false;
  79     ++I;  // Skip over the marker.
  80   }
  81
  82   // If the first character is a number, we need quotes.
  83   if (*I >= '0' && *I <= '9')
  84     NeedQuotes = true;
  85
  86   // Do an initial scan of the string, checking to see if we need quotes or
  87   // to escape a '"' or not.
  88   if (!NeedQuotes)
  89     for (std::string::const_iterator E = X.end(); I != E; ++I)
  90       if (!isCharAcceptable(*I)) {
  91         NeedQuotes = true;
  92         break;
  93       }
  94
  95   // In the common case, we don't need quotes.  Handle this quickly.
  96   if (!NeedQuotes) {
  97     if (NeedPrefix) {
  98       if (Prefix)
  99         Result = Prefix + X;
 100       else
 101         Result = X;
 102       if (PrivatePrefix)
 103         Result = PrivatePrefix + Result;
 104       return Result;
 105     } else
 106       return X.substr(1);
 107   }
 108
 109   // Otherwise, construct the string the expensive way.
 110   for (std::string::const_iterator E = X.end(); I != E; ++I) {
 111     if (*I == '"')
 112       Result += "_QQ_";
 113     else if (*I == '\n')
 114       Result += "_NL_";
 115     else
 116       Result += *I;
 117   }
 118
 119   if (NeedPrefix) {
 120     if (Prefix)
 121       Result = Prefix + X;
 122     else
 123       Result = X;
 124     if (PrivatePrefix)
 125       Result = PrivatePrefix + Result;
 126   }
 127   Result = '"' + Result + '"';
 128   return Result;
 129 }
 130
 131 /// getTypeID - Return a unique ID for the specified LLVM type.
 132 ///
 133 unsigned Mangler::getTypeID(const Type *Ty) {
 134   unsigned &E = TypeMap[Ty];
 135   if (E == 0) E = ++TypeCounter;
 136   return E;
 137 }
 138
 139 std::string Mangler::getValueName(const Value *V) {
 140   if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
 141     return getValueName(GV);
 142
 143   std::string &Name = Memo[V];
 144   if (!Name.empty())
 145     return Name;       // Return the already-computed name for V.
 146
 147   // Always mangle local names.
 148   Name = "ltmp_" + utostr(Count++) + "_" + utostr(getTypeID(V->getType()));
 149   return Name;
 150 }
 151
 152
 153 std::string Mangler::getValueName(const GlobalValue *GV, const char * Suffix) {
 154   // Check to see whether we've already named V.
 155   std::string &Name = Memo[GV];
 156   if (!Name.empty())
 157     return Name;       // Return the already-computed name for V.
 158
 159   // Name mangling occurs as follows:
 160   // - If V is an intrinsic function, do not change name at all
 161   // - Otherwise, mangling occurs if global collides with existing name.
 162   if (isa<Function>(GV) && cast<Function>(GV)->isIntrinsic()) {
 163     Name = GV->getNameStart(); // Is an intrinsic function
 164   } else if (!GV->hasName()) {
 165     // Must mangle the global into a unique ID.
 166     unsigned TypeUniqueID = getTypeID(GV->getType());
 167     static unsigned GlobalID = 0;
 168     Name = "__unnamed_" + utostr(TypeUniqueID) + "_" + utostr(GlobalID++);
 169   } else {
 170     if (GV->hasPrivateLinkage())
 171       Name = makeNameProper(GV->getName() + Suffix, Prefix, PrivatePrefix);
 172     else
 173       Name = makeNameProper(GV->getName() + Suffix, Prefix);
 174   }
 175
 176   return Name;
 177 }
 178
 179 Mangler::Mangler(Module &M, const char *prefix, const char *privatePrefix)
 180   : Prefix(prefix), PrivatePrefix (privatePrefix), UseQuotes(false),
 181     PreserveAsmNames(false), Count(0), TypeCounter(0) {
 182   std::fill(AcceptableChars, array_endof(AcceptableChars), 0);
 183
 184   // Letters and numbers are acceptable.
 185   for (unsigned char X = 'a'; X <= 'z'; ++X)
 186     markCharAcceptable(X);
 187   for (unsigned char X = 'A'; X <= 'Z'; ++X)
 188     markCharAcceptable(X);
 189   for (unsigned char X = '0'; X <= '9'; ++X)
 190     markCharAcceptable(X);
 191
 192   // These chars are acceptable.
 193   markCharAcceptable('_');
 194   markCharAcceptable('$');
 195   markCharAcceptable('.');
 196 }