73 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			73 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C++
		
	
	
	
//===- llvm/CodeGen/AddressPool.cpp - Dwarf Debug Framework ---------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "AddressPool.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/CodeGen/AsmPrinter.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/MC/MCStreamer.h"
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#include "llvm/Target/TargetLoweringObjectFile.h"
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#include <utility>
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using namespace llvm;
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unsigned AddressPool::getIndex(const MCSymbol *Sym, bool TLS) {
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  HasBeenUsed = true;
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  auto IterBool =
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      Pool.insert(std::make_pair(Sym, AddressPoolEntry(Pool.size(), TLS)));
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  return IterBool.first->second.Number;
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}
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MCSymbol *AddressPool::emitHeader(AsmPrinter &Asm, MCSection *Section) {
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  static const uint8_t AddrSize = Asm.getDataLayout().getPointerSize();
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  MCSymbol *EndLabel =
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      Asm.emitDwarfUnitLength("debug_addr", "Length of contribution");
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  Asm.OutStreamer->AddComment("DWARF version number");
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  Asm.emitInt16(Asm.getDwarfVersion());
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  Asm.OutStreamer->AddComment("Address size");
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  Asm.emitInt8(AddrSize);
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  Asm.OutStreamer->AddComment("Segment selector size");
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  Asm.emitInt8(0); // TODO: Support non-zero segment_selector_size.
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  return EndLabel;
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}
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// Emit addresses into the section given.
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void AddressPool::emit(AsmPrinter &Asm, MCSection *AddrSection) {
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  if (isEmpty())
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    return;
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  // Start the dwarf addr section.
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  Asm.OutStreamer->SwitchSection(AddrSection);
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  MCSymbol *EndLabel = nullptr;
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  if (Asm.getDwarfVersion() >= 5)
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    EndLabel = emitHeader(Asm, AddrSection);
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  // Define the symbol that marks the start of the contribution.
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  // It is referenced via DW_AT_addr_base.
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  Asm.OutStreamer->emitLabel(AddressTableBaseSym);
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  // Order the address pool entries by ID
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  SmallVector<const MCExpr *, 64> Entries(Pool.size());
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  for (const auto &I : Pool)
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    Entries[I.second.Number] =
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        I.second.TLS
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            ? Asm.getObjFileLowering().getDebugThreadLocalSymbol(I.first)
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            : MCSymbolRefExpr::create(I.first, Asm.OutContext);
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  for (const MCExpr *Entry : Entries)
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    Asm.OutStreamer->emitValue(Entry, Asm.getDataLayout().getPointerSize());
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  if (EndLabel)
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    Asm.OutStreamer->emitLabel(EndLabel);
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}
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