lib/MC/MCSymbol.cpp

   1 //===- lib/MC/MCSymbol.cpp - MCSymbol implementation ----------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/MC/MCSymbol.h"
  10 #include "llvm/ADT/StringRef.h"
  11 #include "llvm/Config/llvm-config.h"
  12 #include "llvm/MC/MCAsmInfo.h"
  13 #include "llvm/MC/MCContext.h"
  14 #include "llvm/MC/MCExpr.h"
  15 #include "llvm/MC/MCFragment.h"
  16 #include "llvm/Support/Compiler.h"
  17 #include "llvm/Support/Debug.h"
  18 #include "llvm/Support/ErrorHandling.h"
  19 #include "llvm/Support/raw_ostream.h"
  20 #include <cassert>
  21 #include <cstddef>
  22
  23 using namespace llvm;
  24
  25 // Only the address of this fragment is ever actually used.
  26 static MCDummyFragment SentinelFragment(nullptr);
  27
  28 // Sentinel value for the absolute pseudo fragment.
  29 MCFragment *MCSymbol::AbsolutePseudoFragment = &SentinelFragment;
  30
  31 void *MCSymbol::operator new(size_t s, const StringMapEntry<bool> *Name,
  32                              MCContext &Ctx) {
  33   // We may need more space for a Name to account for alignment.  So allocate
  34   // space for the storage type and not the name pointer.
  35   size_t Size = s + (Name ? sizeof(NameEntryStorageTy) : 0);
  36
  37   // For safety, ensure that the alignment of a pointer is enough for an
  38   // MCSymbol.  This also ensures we don't need padding between the name and
  39   // symbol.
  40   static_assert((unsigned)alignof(MCSymbol) <= alignof(NameEntryStorageTy),
  41                 "Bad alignment of MCSymbol");
  42   void *Storage = Ctx.allocate(Size, alignof(NameEntryStorageTy));
  43   NameEntryStorageTy *Start = static_cast<NameEntryStorageTy*>(Storage);
  44   NameEntryStorageTy *End = Start + (Name ? 1 : 0);
  45   return End;
  46 }
  47
  48 void MCSymbol::setVariableValue(const MCExpr *Value) {
  49   assert(!IsUsed && "Cannot set a variable that has already been used.");
  50   assert(Value && "Invalid variable value!");
  51   assert((SymbolContents == SymContentsUnset ||
  52           SymbolContents == SymContentsVariable) &&
  53          "Cannot give common/offset symbol a variable value");
  54   this->Value = Value;
  55   SymbolContents = SymContentsVariable;
  56   setUndefined();
  57 }
  58
  59 void MCSymbol::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
  60   // The name for this MCSymbol is required to be a valid target name.  However,
  61   // some targets support quoting names with funny characters.  If the name
  62   // contains a funny character, then print it quoted.
  63   StringRef Name = getName();
  64   if (!MAI || MAI->isValidUnquotedName(Name)) {
  65     OS << Name;
  66     return;
  67   }
  68
  69   if (MAI && !MAI->supportsNameQuoting())
  70     report_fatal_error("Symbol name with unsupported characters");
  71
  72   OS << '"';
  73   for (char C : Name) {
  74     if (C == '\n')
  75       OS << "\\n";
  76     else if (C == '"')
  77       OS << "\\\"";
  78     else
  79       OS << C;
  80   }
  81   OS << '"';
  82 }
  83
  84 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  85 LLVM_DUMP_METHOD void MCSymbol::dump() const {
  86   dbgs() << *this;
  87 }
  88 #endif