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   std::string Result;
  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     // If X does not start with (char)1, add the prefix.
  44     std::string::const_iterator I = X.begin();
  45     if (*I != 1)
  46       Result = Prefix;
  47     else
  48       ++I;  // Skip over the marker.
  49
  50     // Mangle the first letter specially, don't allow numbers.
  51     if (*I >= '0' && *I <= '9')
  52       Result += MangleLetter(*I++);
  53
  54     for (std::string::const_iterator E = X.end(); I != E; ++I) {
  55       if (!isCharAcceptable(*I))
  56         Result += MangleLetter(*I);
  57       else
  58         Result += *I;
  59     }
  60   } else {
  61     bool NeedsQuotes = false;
  62
  63     std::string::const_iterator I = X.begin();
  64     if (*I == 1)
  65       ++I;  // Skip over the marker.
  66
  67     // If the first character is a number, we need quotes.
  68     if (*I >= '0' && *I <= '9')
  69       NeedsQuotes = true;
  70
  71     // Do an initial scan of the string, checking to see if we need quotes or
  72     // to escape a '"' or not.
  73     if (!NeedsQuotes)
  74       for (std::string::const_iterator E = X.end(); I != E; ++I)
  75         if (!isCharAcceptable(*I)) {
  76           NeedsQuotes = true;
  77           break;
  78         }
  79
  80     // In the common case, we don't need quotes.  Handle this quickly.
  81     if (!NeedsQuotes) {
  82       if (*X.begin() != 1)
  83         return Prefix+X;
  84       else
  85         return X.substr(1);
  86     }
  87
  88     // Otherwise, construct the string the expensive way.
  89     I = X.begin();
  90
  91     // If X does not start with (char)1, add the prefix.
  92     if (*I != 1)
  93       Result = Prefix;
  94     else
  95       ++I;   // Skip the marker if present.
  96
  97     for (std::string::const_iterator E = X.end(); I != E; ++I) {
  98       if (*I == '"')
  99         Result += "_QQ_";
 100       else if (*I == '\n')
 101         Result += "_NL_";
 102       else
 103         Result += *I;
 104     }
 105     Result = '"' + Result + '"';
 106   }
 107   return Result;
 108 }
 109
 110 /// getTypeID - Return a unique ID for the specified LLVM type.
 111 ///
 112 unsigned Mangler::getTypeID(const Type *Ty) {
 113   unsigned &E = TypeMap[Ty];
 114   if (E == 0) E = ++TypeCounter;
 115   return E;
 116 }
 117
 118 std::string Mangler::getValueName(const Value *V) {
 119   if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))
 120     return getValueName(GV);
 121
 122   std::string &Name = Memo[V];
 123   if (!Name.empty())
 124     return Name;       // Return the already-computed name for V.
 125
 126   // Always mangle local names.
 127   Name = "ltmp_" + utostr(Count++) + "_" + utostr(getTypeID(V->getType()));
 128   return Name;
 129 }
 130
 131
 132 std::string Mangler::getValueName(const GlobalValue *GV, const char * Suffix) {
 133   // Check to see whether we've already named V.
 134   std::string &Name = Memo[GV];
 135   if (!Name.empty())
 136     return Name;       // Return the already-computed name for V.
 137
 138   // Name mangling occurs as follows:
 139   // - If V is an intrinsic function, do not change name at all
 140   // - Otherwise, mangling occurs if global collides with existing name.
 141   if (isa<Function>(GV) && cast<Function>(GV)->isIntrinsic()) {
 142     Name = GV->getNameStart(); // Is an intrinsic function
 143   } else if (!GV->hasName()) {
 144     // Must mangle the global into a unique ID.
 145     unsigned TypeUniqueID = getTypeID(GV->getType());
 146     static unsigned GlobalID = 0;
 147     Name = "__unnamed_" + utostr(TypeUniqueID) + "_" + utostr(GlobalID++);
 148   } else {
 149     Name = makeNameProper(GV->getName() + Suffix, Prefix);
 150     std::string prefix;
 151     if (GV->hasPrivateLinkage())
 152       prefix = PrivatePrefix;
 153     else
 154       prefix = "";
 155     Name = prefix + Name;
 156   }
 157
 158   return Name;
 159 }
 160
 161 Mangler::Mangler(Module &M, const char *prefix, const char *privatePrefix)
 162   : Prefix(prefix), PrivatePrefix (privatePrefix), UseQuotes(false),
 163     PreserveAsmNames(false), Count(0), TypeCounter(0) {
 164   std::fill(AcceptableChars, array_endof(AcceptableChars), 0);
 165
 166   // Letters and numbers are acceptable.
 167   for (unsigned char X = 'a'; X <= 'z'; ++X)
 168     markCharAcceptable(X);
 169   for (unsigned char X = 'A'; X <= 'Z'; ++X)
 170     markCharAcceptable(X);
 171   for (unsigned char X = '0'; X <= '9'; ++X)
 172     markCharAcceptable(X);
 173
 174   // These chars are acceptable.
 175   markCharAcceptable('_');
 176   markCharAcceptable('$');
 177   markCharAcceptable('.');
 178 }