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 89