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/ADT/StringRef.h"
  12 #include "llvm/Config/llvm-config.h"
  13 #include "llvm/MC/MCAsmInfo.h"
  14 #include "llvm/MC/MCContext.h"
  15 #include "llvm/MC/MCExpr.h"
  16 #include "llvm/MC/MCFragment.h"
  17 #include "llvm/Support/Compiler.h"
  18 #include "llvm/Support/Debug.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #include "llvm/Support/raw_ostream.h"
  21 #include <cassert>
  22 #include <cstddef>
  23
  24 using namespace llvm;
  25
  26 // Only the address of this fragment is ever actually used.
  27 static MCDummyFragment SentinelFragment(nullptr);
  28
  29 // Sentinel value for the absolute pseudo fragment.
  30 MCFragment *MCSymbol::AbsolutePseudoFragment = &SentinelFragment;
  31
  32 void *MCSymbol::operator new(size_t s, const StringMapEntry<bool> *Name,
  33                              MCContext &Ctx) {
  34   // We may need more space for a Name to account for alignment.  So allocate
  35   // space for the storage type and not the name pointer.
  36   size_t Size = s + (Name ? sizeof(NameEntryStorageTy) : 0);
  37
  38   // For safety, ensure that the alignment of a pointer is enough for an
  39   // MCSymbol.  This also ensures we don't need padding between the name and
  40   // symbol.
  41   static_assert((unsigned)alignof(MCSymbol) <= alignof(NameEntryStorageTy),
  42                 "Bad alignment of MCSymbol");
  43   void *Storage = Ctx.allocate(Size, alignof(NameEntryStorageTy));
  44   NameEntryStorageTy *Start = static_cast<NameEntryStorageTy*>(Storage);
  45   NameEntryStorageTy *End = Start + (Name ? 1 : 0);
  46   return End;
  47 }
  48
  49 void MCSymbol::setVariableValue(const MCExpr *Value) {
  50   assert(!IsUsed && "Cannot set a variable that has already been used.");
  51   assert(Value && "Invalid variable value!");
  52   assert((SymbolContents == SymContentsUnset ||
  53           SymbolContents == SymContentsVariable) &&
  54          "Cannot give common/offset symbol a variable value");
  55   this->Value = Value;
  56   SymbolContents = SymContentsVariable;
  57   setUndefined();
  58 }
  59
  60 void MCSymbol::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
  61   // The name for this MCSymbol is required to be a valid target name.  However,
  62   // some targets support quoting names with funny characters.  If the name
  63   // contains a funny character, then print it quoted.
  64   StringRef Name = getName();
  65   if (!MAI || MAI->isValidUnquotedName(Name)) {
  66     OS << Name;
  67     return;
  68   }
  69
  70   if (MAI && !MAI->supportsNameQuoting())
  71     report_fatal_error("Symbol name with unsupported characters");
  72
  73   OS << '"';
  74   for (char C : Name) {
  75     if (C == '\n')
  76       OS << "\\n";
  77     else if (C == '"')
  78       OS << "\\\"";
  79     else
  80       OS << C;
  81   }
  82   OS << '"';
  83 }
  84
  85 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  86 LLVM_DUMP_METHOD void MCSymbol::dump() const {
  87   dbgs() << *this;
  88 }
  89 #endif