llvm/lib/Object/RecordStreamer.h

   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/MapVector.h"
  14 #include "llvm/ADT/StringMap.h"
  15 #include "llvm/MC/MCDirectives.h"
  16 #include "llvm/MC/MCStreamer.h"
  17 #include "llvm/Support/SMLoc.h"
  18 #include <vector>
  19
  20 namespace llvm {
  21
  22 class MCSymbol;
  23 class Module;
  24
  25 class RecordStreamer : public MCStreamer {
  26 public:
  27   enum State { NeverSeen, Global, Defined, DefinedGlobal, DefinedWeak, Used,
  28                UndefinedWeak};
  29
  30 private:
  31   const Module &M;
  32   StringMap<State> Symbols;
  33   // Map of aliases created by .symver directives, saved so we can update
  34   // their symbol binding after parsing complete. This maps from each
  35   // aliasee to its list of aliases.
  36   MapVector<const MCSymbol *, std::vector<StringRef>> SymverAliasMap;
  37
  38   /// Get the state recorded for the given symbol.
  39   State getSymbolState(const MCSymbol *Sym);
  40
  41   void markDefined(const MCSymbol &Symbol);
  42   void markGlobal(const MCSymbol &Symbol, MCSymbolAttr Attribute);
  43   void markUsed(const MCSymbol &Symbol);
  44   void visitUsedSymbol(const MCSymbol &Sym) override;
  45
  46 public:
  47   RecordStreamer(MCContext &Context, const Module &M);
  48
  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                     Align ByteAlignment, SMLoc Loc = SMLoc()) override;
  54   void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
  55                         Align 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