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llvm-mirror/lib/Object/RecordStreamer.h
Vlad Tsyrklevich e5f98a3c30 LowerTypeTests: Propagate symver directives
Summary:
This change fixes https://crbug.com/834474, a build failure caused by
LowerTypeTests not preserving .symver symbol versioning directives for
exported functions. Emit symver information to ThinLTO summary data and
then propagate symver directives for exported functions to the merged
module.

Emitting symver information to the summaries increases the size of
intermediate build artifacts for a Chromium build by less than 0.2%.

Reviewers: pcc

Reviewed By: pcc

Subscribers: tejohnson, mehdi_amini, eraman, llvm-commits, eugenis, kcc

Differential Revision: https://reviews.llvm.org/D45798

llvm-svn: 330387
2018-04-20 01:36:48 +00:00

80 lines
2.7 KiB
C++

//===- RecordStreamer.h - Record asm defined and used symbols ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_OBJECT_RECORDSTREAMER_H
#define LLVM_LIB_OBJECT_RECORDSTREAMER_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/SMLoc.h"
#include <vector>
namespace llvm {
class GlobalValue;
class Module;
class RecordStreamer : public MCStreamer {
public:
enum State { NeverSeen, Global, Defined, DefinedGlobal, DefinedWeak, Used,
UndefinedWeak};
private:
const Module &M;
StringMap<State> Symbols;
// Map of aliases created by .symver directives, saved so we can update
// their symbol binding after parsing complete. This maps from each
// aliasee to its list of aliases.
DenseMap<const MCSymbol *, std::vector<StringRef>> SymverAliasMap;
/// Get the state recorded for the given symbol.
State getSymbolState(const MCSymbol *Sym);
void markDefined(const MCSymbol &Symbol);
void markGlobal(const MCSymbol &Symbol, MCSymbolAttr Attribute);
void markUsed(const MCSymbol &Symbol);
void visitUsedSymbol(const MCSymbol &Sym) override;
public:
RecordStreamer(MCContext &Context, const Module &M);
void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
bool) override;
void EmitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()) override;
void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) override;
bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override;
void EmitZerofill(MCSection *Section, MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) override;
void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
unsigned ByteAlignment) override;
/// Record .symver aliases for later processing.
void emitELFSymverDirective(StringRef AliasName,
const MCSymbol *Aliasee) override;
// Emit ELF .symver aliases and ensure they have the same binding as the
// defined symbol they alias with.
void flushSymverDirectives();
// Symbols iterators
using const_iterator = StringMap<State>::const_iterator;
const_iterator begin();
const_iterator end();
// SymverAliasMap iterators
using const_symver_iterator = decltype(SymverAliasMap)::const_iterator;
iterator_range<const_symver_iterator> symverAliases();
};
} // end namespace llvm
#endif // LLVM_LIB_OBJECT_RECORDSTREAMER_H