2017-03-31 09:46:30 +08:00
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//===-- RecordStreamer.cpp - Record asm defined and used symbols ----------===//
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2014-07-04 02:59:23 +08:00
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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2014-07-05 06:44:18 +08:00
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#include "RecordStreamer.h"
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2014-07-04 02:59:23 +08:00
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#include "llvm/MC/MCSymbol.h"
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using namespace llvm;
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void RecordStreamer::markDefined(const MCSymbol &Symbol) {
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State &S = Symbols[Symbol.getName()];
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switch (S) {
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case DefinedGlobal:
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case Global:
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S = DefinedGlobal;
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break;
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case NeverSeen:
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case Defined:
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case Used:
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S = Defined;
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break;
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2016-09-16 01:54:22 +08:00
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case DefinedWeak:
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2016-06-23 04:48:15 +08:00
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break;
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2016-09-16 01:54:22 +08:00
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case UndefinedWeak:
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S = DefinedWeak;
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2014-07-04 02:59:23 +08:00
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}
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}
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2016-06-23 04:48:15 +08:00
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void RecordStreamer::markGlobal(const MCSymbol &Symbol,
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MCSymbolAttr Attribute) {
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2014-07-04 02:59:23 +08:00
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State &S = Symbols[Symbol.getName()];
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switch (S) {
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case DefinedGlobal:
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case Defined:
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2016-09-16 01:54:22 +08:00
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S = (Attribute == MCSA_Weak) ? DefinedWeak : DefinedGlobal;
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2014-07-04 02:59:23 +08:00
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break;
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case NeverSeen:
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case Global:
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case Used:
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2016-09-16 01:54:22 +08:00
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S = (Attribute == MCSA_Weak) ? UndefinedWeak : Global;
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2016-06-23 04:48:15 +08:00
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break;
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2016-09-16 01:54:22 +08:00
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case UndefinedWeak:
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case DefinedWeak:
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2014-07-04 02:59:23 +08:00
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break;
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}
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}
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void RecordStreamer::markUsed(const MCSymbol &Symbol) {
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State &S = Symbols[Symbol.getName()];
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switch (S) {
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case DefinedGlobal:
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case Defined:
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case Global:
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2016-09-16 01:54:22 +08:00
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case DefinedWeak:
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case UndefinedWeak:
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2014-07-04 02:59:23 +08:00
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break;
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case NeverSeen:
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case Used:
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S = Used;
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break;
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}
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}
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void RecordStreamer::visitUsedSymbol(const MCSymbol &Sym) { markUsed(Sym); }
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RecordStreamer::const_iterator RecordStreamer::begin() {
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return Symbols.begin();
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}
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RecordStreamer::const_iterator RecordStreamer::end() { return Symbols.end(); }
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RecordStreamer::RecordStreamer(MCContext &Context) : MCStreamer(Context) {}
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void RecordStreamer::EmitInstruction(const MCInst &Inst,
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const MCSubtargetInfo &STI) {
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MCStreamer::EmitInstruction(Inst, STI);
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}
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2017-02-10 23:13:12 +08:00
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void RecordStreamer::EmitLabel(MCSymbol *Symbol, SMLoc Loc) {
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2014-07-04 02:59:23 +08:00
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MCStreamer::EmitLabel(Symbol);
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markDefined(*Symbol);
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}
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void RecordStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
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markDefined(*Symbol);
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MCStreamer::EmitAssignment(Symbol, Value);
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}
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bool RecordStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
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MCSymbolAttr Attribute) {
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2016-06-18 02:20:14 +08:00
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if (Attribute == MCSA_Global || Attribute == MCSA_Weak)
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2016-06-23 04:48:15 +08:00
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markGlobal(*Symbol, Attribute);
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2016-08-03 11:51:42 +08:00
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if (Attribute == MCSA_LazyReference)
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markUsed(*Symbol);
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2014-07-04 02:59:23 +08:00
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return true;
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}
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2015-05-22 03:20:38 +08:00
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void RecordStreamer::EmitZerofill(MCSection *Section, MCSymbol *Symbol,
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2014-07-04 02:59:23 +08:00
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uint64_t Size, unsigned ByteAlignment) {
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markDefined(*Symbol);
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}
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void RecordStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
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unsigned ByteAlignment) {
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markDefined(*Symbol);
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}
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Perform symbol binding for .symver versioned symbols
Summary:
In a .symver assembler directive like:
.symver name, name2@@nodename
"name2@@nodename" should get the same symbol binding as "name".
While the ELF object writer is updating the symbol binding for .symver
aliases before emitting the object file, not doing so when the module
inline assembly is handled by the RecordStreamer is causing the wrong
behavior in *LTO mode.
E.g. when "name" is global, "name2@@nodename" must also be marked as
global. Otherwise, the symbol is skipped when iterating over the LTO
InputFile symbols (InputFile::Symbol::shouldSkip). So, for example,
when performing any *LTO via the gold-plugin, the versioned symbol
definition is not recorded by the plugin and passed back to the
linker. If the object was in an archive, and there were no other symbols
needed from that object, the object would not be included in the final
link and references to the versioned symbol are undefined.
The llvm-lto2 tests added will give an error about an unused symbol
resolution without the fix.
Reviewers: rafael, pcc
Reviewed By: pcc
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D30485
llvm-svn: 297332
2017-03-09 08:19:49 +08:00
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void RecordStreamer::emitELFSymverDirective(MCSymbol *Alias,
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const MCSymbol *Aliasee) {
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SymverAliasMap[Aliasee].push_back(Alias);
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}
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