LLVM  6.0.0svn
MCSymbol.cpp
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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/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"
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.
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 
49  assert(!IsUsed && "Cannot set a variable that has already been used.");
50  assert(Value && "Invalid variable value!");
53  "Cannot give common/offset symbol a variable value");
54  this->Value = Value;
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.
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)
86  dbgs() << *this;
87 }
88 #endif
uint64_t CallInst * C
union { const StringMapEntry< bool > *NameEntry NameEntryStorageTy
The name for a symbol.
Definition: MCSymbol.h:149
LLVM_ATTRIBUTE_NORETURN void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:103
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
#define LLVM_DUMP_METHOD
Mark debug helper function definitions like dump() that should not be stripped from debug builds...
Definition: Compiler.h:449
StringMapEntry - This is used to represent one value that is inserted into a StringMap.
Definition: StringMap.h:126
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:42
bool supportsNameQuoting() const
Definition: MCAsmInfo.h:495
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:36
Context object for machine code objects.
Definition: MCContext.h:59
This class is intended to be used as a base class for asm properties and features specific to the tar...
Definition: MCAsmInfo.h:56
static const unsigned End
static MCFragment * AbsolutePseudoFragment
Definition: MCSymbol.h:64
virtual bool isValidUnquotedName(StringRef Name) const
Return true if the identifier Name does not need quotes to be syntactically correct.
Definition: MCAsmInfo.cpp:94
void setUndefined()
Mark the symbol as undefined.
Definition: MCSymbol.h:280
unsigned IsUsed
IsUsed - True if this symbol has been used.
Definition: MCSymbol.h:92
unsigned SymbolContents
This is actually a Contents enumerator, but is unsigned to avoid sign extension and achieve better bi...
Definition: MCSymbol.h:111
void setVariableValue(const MCExpr *Value)
Definition: MCSymbol.cpp:48
void dump() const
dump - Print the value to stderr.
Definition: MCSymbol.cpp:85
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
constexpr char Size[]
Key for Kernel::Arg::Metadata::mSize.
static MCDummyFragment SentinelFragment(nullptr)
StringRef getName() const
getName - Get the symbol name.
Definition: MCSymbol.h:203
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
LLVM Value Representation.
Definition: Value.h:73
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
const MCExpr * Value
If non-null, the value for a variable symbol.
Definition: MCSymbol.h:137
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
void print(raw_ostream &OS, const MCAsmInfo *MAI) const
print - Print the value to the stream OS.
Definition: MCSymbol.cpp:59