1 //===- RecordStreamer.h - Record asm defined and used symbols ---*- C++ -*-===// 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 #ifndef LLVM_LIB_OBJECT_RECORDSTREAMER_H 10 #define LLVM_LIB_OBJECT_RECORDSTREAMER_H 11 12 #include "llvm/ADT/DenseMap.h" 13 #include "llvm/ADT/StringMap.h" 14 #include "llvm/MC/MCDirectives.h" 15 #include "llvm/MC/MCStreamer.h" 16 #include "llvm/Support/SMLoc.h" 17 #include <vector> 18 19 namespace llvm { 20 21 class MCSymbol; 22 class Module; 23 24 class RecordStreamer : public MCStreamer { 25 public: 26 enum State { NeverSeen, Global, Defined, DefinedGlobal, DefinedWeak, Used, 27 UndefinedWeak}; 28 29 private: 30 const Module &M; 31 StringMap<State> Symbols; 32 // Map of aliases created by .symver directives, saved so we can update 33 // their symbol binding after parsing complete. This maps from each 34 // aliasee to its list of aliases. 35 DenseMap<const MCSymbol *, std::vector<StringRef>> SymverAliasMap; 36 37 /// Get the state recorded for the given symbol. 38 State getSymbolState(const MCSymbol *Sym); 39 40 void markDefined(const MCSymbol &Symbol); 41 void markGlobal(const MCSymbol &Symbol, MCSymbolAttr Attribute); 42 void markUsed(const MCSymbol &Symbol); 43 void visitUsedSymbol(const MCSymbol &Sym) override; 44 45 public: 46 RecordStreamer(MCContext &Context, const Module &M); 47 48 void emitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI) override; 49 void emitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override; 50 void emitAssignment(MCSymbol *Symbol, const MCExpr *Value) override; 51 bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override; 52 void emitZerofill(MCSection *Section, MCSymbol *Symbol, uint64_t Size, 53 unsigned ByteAlignment, SMLoc Loc = SMLoc()) override; 54 void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 55 unsigned ByteAlignment) override; 56 57 // Ignore COFF-specific directives; we do not need any information from them, 58 // but the default implementation of these methods crashes, so we override 59 // them with versions that do nothing. 60 void BeginCOFFSymbolDef(const MCSymbol *Symbol) override {} 61 void EmitCOFFSymbolStorageClass(int StorageClass) override {} 62 void EmitCOFFSymbolType(int Type) override {} 63 void EndCOFFSymbolDef() override {} 64 65 /// Record .symver aliases for later processing. 66 void emitELFSymverDirective(const MCSymbol *OriginalSym, StringRef Name, 67 bool KeepOriginalSym) override; 68 69 // Emit ELF .symver aliases and ensure they have the same binding as the 70 // defined symbol they alias with. 71 void flushSymverDirectives(); 72 73 // Symbols iterators 74 using const_iterator = StringMap<State>::const_iterator; 75 const_iterator begin(); 76 const_iterator end(); 77 78 // SymverAliasMap iterators 79 using const_symver_iterator = decltype(SymverAliasMap)::const_iterator; 80 iterator_range<const_symver_iterator> symverAliases(); 81 }; 82 83 } // end namespace llvm 84 85 #endif // LLVM_LIB_OBJECT_RECORDSTREAMER_H 86