lib/MC/MCSymbol.cpp

   1 //===- lib/MC/MCSymbol.cpp - MCSymbol implementation ----------------------===//
   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 #include "llvm/MC/MCSymbol.h"
  11 #include "llvm/MC/MCExpr.h"
  12 #include "llvm/Support/Debug.h"
  13 #include "llvm/Support/raw_ostream.h"
  14 using namespace llvm;
  15
  16 // Sentinel value for the absolute pseudo section.
  17 const MCSection *MCSymbol::AbsolutePseudoSection =
  18   reinterpret_cast<const MCSection *>(1);
  19
  20 static bool isAcceptableChar(char C) {
  21   if ((C < 'a' || C > 'z') &&
  22       (C < 'A' || C > 'Z') &&
  23       (C < '0' || C > '9') &&
  24       C != '_' && C != '$' && C != '.' && C != '@')
  25     return false;
  26   return true;
  27 }
  28
  29 /// NameNeedsQuoting - Return true if the identifier \arg Str needs quotes to be
  30 /// syntactically correct.
  31 static bool NameNeedsQuoting(StringRef Str) {
  32   assert(!Str.empty() && "Cannot create an empty MCSymbol");
  33
  34   // If any of the characters in the string is an unacceptable character, force
  35   // quotes.
  36   for (unsigned i = 0, e = Str.size(); i != e; ++i)
  37     if (!isAcceptableChar(Str[i]))
  38       return true;
  39   return false;
  40 }
  41
  42 const MCSymbol &MCSymbol::AliasedSymbol() const {
  43   const MCSymbol *S = this;
  44   while (S->isVariable()) {
  45     const MCExpr *Value = S->getVariableValue();
  46     if (Value->getKind() != MCExpr::SymbolRef)
  47       return *S;
  48     const MCSymbolRefExpr *Ref = static_cast<const MCSymbolRefExpr*>(Value);
  49     S = &Ref->getSymbol();
  50   }
  51   return *S;
  52 }
  53
  54 void MCSymbol::setVariableValue(const MCExpr *Value) {
  55   assert(!IsUsed && "Cannot set a variable that has already been used.");
  56   assert(Value && "Invalid variable value!");
  57   assert((isUndefined() || (isAbsolute() && isa<MCConstantExpr>(Value))) &&
  58          "Invalid redefinition!");
  59   this->Value = Value;
  60
  61   // Mark the variable as absolute as appropriate.
  62   if (isa<MCConstantExpr>(Value))
  63     setAbsolute();
  64 }
  65
  66 void MCSymbol::print(raw_ostream &OS) const {
  67   // The name for this MCSymbol is required to be a valid target name.  However,
  68   // some targets support quoting names with funny characters.  If the name
  69   // contains a funny character, then print it quoted.
  70   if (!NameNeedsQuoting(getName())) {
  71     OS << getName();
  72     return;
  73   }
  74
  75   OS << '"' << getName() << '"';
  76 }
  77
  78 void MCSymbol::dump() const {
  79   print(dbgs());
  80 }