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