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 88