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a5032b2633
We could only do this in limited ways (since we emit the TUs first, we can't use ref_addr (& we can't use that in Split DWARF either) - so we had to synthesize declarations into the TUs) and they were ambiguous in some cases (if the CU type had internal linkage, parsing the TU would require knowing which CU was referencing the TU to know which type the declaration was for, which seems not-ideal). So to avoid all that, let's just not reference types defined in the CU from TUs - instead moving the TU type into the CU (recursively). This does increase debug info size (by pulling more things out of type units, into the compile unit) - about 2% of uncompressed dwp file size for clang -O0 -g -gsplit-dwarf. (5% .debug_info.dwo section size increase in the .dwp)
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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resetUsedFlag(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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