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/MC/MCSymbol.h"
17#include "llvm/Support/SMLoc.h"
18#include <vector>
19
20namespace llvm {
21
22class GlobalValue;
23class Module;
24
25class RecordStreamer : public MCStreamer {
26public:
27  enum State { NeverSeen, Global, Defined, DefinedGlobal, DefinedWeak, Used,
28               UndefinedWeak};
29
30private:
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  DenseMap<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
46public:
47  RecordStreamer(MCContext &Context, const Module &M);
48
49  void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI) override;
50  void EmitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
51  void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
52  bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
53  void EmitZerofill(MCSection *Section, MCSymbol *Symbol, uint64_t Size,
54                    unsigned ByteAlignment, SMLoc Loc = SMLoc()) override;
55  void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
56                        unsigned ByteAlignment) override;
57
58  // Ignore COFF-specific directives; we do not need any information from them,
59  // but the default implementation of these methods crashes, so we override
60  // them with versions that do nothing.
61  void BeginCOFFSymbolDef(const MCSymbol *Symbol) override {}
62  void EmitCOFFSymbolStorageClass(int StorageClass) override {}
63  void EmitCOFFSymbolType(int Type) override {}
64  void EndCOFFSymbolDef() override {}
65
66  /// Record .symver aliases for later processing.
67  void emitELFSymverDirective(StringRef AliasName,
68                              const MCSymbol *Aliasee) override;
69
70  // Emit ELF .symver aliases and ensure they have the same binding as the
71  // defined symbol they alias with.
72  void flushSymverDirectives();
73
74  // Symbols iterators
75  using const_iterator = StringMap<State>::const_iterator;
76  const_iterator begin();
77  const_iterator end();
78
79  // SymverAliasMap iterators
80  using const_symver_iterator = decltype(SymverAliasMap)::const_iterator;
81  iterator_range<const_symver_iterator> symverAliases();
82};
83
84} // end namespace llvm
85
86#endif // LLVM_LIB_OBJECT_RECORDSTREAMER_H
87