MCSymbol.cpp revision 94ed5fca3f5ab5acb74e70b8393b837131e7110c
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" 14using namespace llvm; 15 16// Sentinel value for the absolute pseudo section. 17const MCSection *MCSymbol::AbsolutePseudoSection = 18 reinterpret_cast<const MCSection *>(1); 19 20static 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. 31static 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 42const 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 54void 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 66void 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 78void MCSymbol::dump() const { 79 print(dbgs()); 80} 81