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78ab659bb4
This recommits r337910 after fixing an "ambiguous call to addAttribute" error with some compilers (gcc circa 4.9 and MSVC). It seems that these compilers will consider a "false -> pointer" conversion during overload resolution. This creates ambiguity because one I added an overload which takes a MCExpr * as an argument. I fix this by making the new overload take MCExpr&, which avoids the conversion. It also documents the fact that we expect a valid MCExpr object. Original commit message follows: The motivation for this is D49493, where we'd like to test details of debug_str_offsets behavior which is difficult to trigger from a traditional test. This adds the plubming necessary for dwarfgen to generate this section. The more interesting changes are: - I've moved emitStringOffsetsTableHeader function from DwarfFile to DwarfStringPool, so I can generate the section header more easily from the unit test. - added a new addAttribute overload taking an MCExpr*. This is used to generate the DW_AT_str_offsets_base, which links a compile unit to the offset table. I've also added a basic test for reading and writing DW_form_strx forms. Reviewers: dblaikie, JDevlieghere, probinson Subscribers: llvm-commits, aprantl Differential Revision: https://reviews.llvm.org/D49670 llvm-svn: 337933
101 lines
3.2 KiB
C++
101 lines
3.2 KiB
C++
//===- llvm/CodeGen/DwarfFile.cpp - Dwarf Debug Framework -----------------===//
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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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#include "DwarfFile.h"
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#include "DwarfCompileUnit.h"
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#include "DwarfDebug.h"
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#include "DwarfUnit.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/CodeGen/DIE.h"
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#include "llvm/IR/DebugInfoMetadata.h"
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#include "llvm/MC/MCStreamer.h"
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#include <algorithm>
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#include <cstdint>
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using namespace llvm;
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DwarfFile::DwarfFile(AsmPrinter *AP, StringRef Pref, BumpPtrAllocator &DA)
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: Asm(AP), Abbrevs(AbbrevAllocator), StrPool(DA, *Asm, Pref) {}
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void DwarfFile::addUnit(std::unique_ptr<DwarfCompileUnit> U) {
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CUs.push_back(std::move(U));
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}
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// Emit the various dwarf units to the unit section USection with
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// the abbreviations going into ASection.
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void DwarfFile::emitUnits(bool UseOffsets) {
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for (const auto &TheU : CUs)
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emitUnit(TheU.get(), UseOffsets);
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}
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void DwarfFile::emitUnit(DwarfUnit *TheU, bool UseOffsets) {
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DIE &Die = TheU->getUnitDie();
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MCSection *USection = TheU->getSection();
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Asm->OutStreamer->SwitchSection(USection);
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TheU->emitHeader(UseOffsets);
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Asm->emitDwarfDIE(Die);
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}
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// Compute the size and offset for each DIE.
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void DwarfFile::computeSizeAndOffsets() {
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// Offset from the first CU in the debug info section is 0 initially.
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unsigned SecOffset = 0;
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// Iterate over each compile unit and set the size and offsets for each
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// DIE within each compile unit. All offsets are CU relative.
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for (const auto &TheU : CUs) {
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TheU->setDebugSectionOffset(SecOffset);
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SecOffset += computeSizeAndOffsetsForUnit(TheU.get());
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}
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}
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unsigned DwarfFile::computeSizeAndOffsetsForUnit(DwarfUnit *TheU) {
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// CU-relative offset is reset to 0 here.
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unsigned Offset = sizeof(int32_t) + // Length of Unit Info
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TheU->getHeaderSize(); // Unit-specific headers
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// The return value here is CU-relative, after laying out
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// all of the CU DIE.
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return computeSizeAndOffset(TheU->getUnitDie(), Offset);
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}
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// Compute the size and offset of a DIE. The offset is relative to start of the
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// CU. It returns the offset after laying out the DIE.
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unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
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return Die.computeOffsetsAndAbbrevs(Asm, Abbrevs, Offset);
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}
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void DwarfFile::emitAbbrevs(MCSection *Section) { Abbrevs.Emit(Asm, Section); }
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// Emit strings into a string section.
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void DwarfFile::emitStrings(MCSection *StrSection, MCSection *OffsetSection,
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bool UseRelativeOffsets) {
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StrPool.emit(*Asm, StrSection, OffsetSection, UseRelativeOffsets);
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}
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bool DwarfFile::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
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auto &ScopeVars = ScopeVariables[LS];
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const DILocalVariable *DV = Var->getVariable();
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if (unsigned ArgNum = DV->getArg()) {
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auto Cached = ScopeVars.Args.find(ArgNum);
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if (Cached == ScopeVars.Args.end())
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ScopeVars.Args[ArgNum] = Var;
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else {
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Cached->second->addMMIEntry(*Var);
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return false;
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}
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} else {
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ScopeVars.Locals.push_back(Var);
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}
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return true;
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}
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