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//===- llvm/CodeGen/DwarfFile.cpp - Dwarf Debug Framework -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "DwarfFile.h"
#include "DwarfCompileUnit.h"
#include "DwarfDebug.h"
#include "DwarfUnit.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/DIE.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/MC/MCStreamer.h"
#include <algorithm>
#include <cstdint>
using namespace llvm;
DwarfFile::DwarfFile(AsmPrinter *AP, StringRef Pref, BumpPtrAllocator &DA)
: Asm(AP), Abbrevs(AbbrevAllocator), StrPool(DA, *Asm, Pref) {}
void DwarfFile::addUnit(std::unique_ptr<DwarfCompileUnit> U) {
CUs.push_back(std::move(U));
}
// Emit the various dwarf units to the unit section USection with
// the abbreviations going into ASection.
void DwarfFile::emitUnits(bool UseOffsets) {
for (const auto &TheU : CUs)
emitUnit(TheU.get(), UseOffsets);
}
void DwarfFile::emitUnit(DwarfUnit *TheU, bool UseOffsets) {
DIE &Die = TheU->getUnitDie();
MCSection *USection = TheU->getSection();
Asm->OutStreamer->SwitchSection(USection);
TheU->emitHeader(UseOffsets);
Asm->emitDwarfDIE(Die);
}
// Compute the size and offset for each DIE.
void DwarfFile::computeSizeAndOffsets() {
// Offset from the first CU in the debug info section is 0 initially.
unsigned SecOffset = 0;
// Iterate over each compile unit and set the size and offsets for each
// DIE within each compile unit. All offsets are CU relative.
for (const auto &TheU : CUs) {
TheU->setDebugSectionOffset(SecOffset);
SecOffset += computeSizeAndOffsetsForUnit(TheU.get());
}
}
unsigned DwarfFile::computeSizeAndOffsetsForUnit(DwarfUnit *TheU) {
// CU-relative offset is reset to 0 here.
unsigned Offset = sizeof(int32_t) + // Length of Unit Info
TheU->getHeaderSize(); // Unit-specific headers
// The return value here is CU-relative, after laying out
// all of the CU DIE.
return computeSizeAndOffset(TheU->getUnitDie(), Offset);
}
// Compute the size and offset of a DIE. The offset is relative to start of the
// CU. It returns the offset after laying out the DIE.
unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
return Die.computeOffsetsAndAbbrevs(Asm, Abbrevs, Offset);
}
void DwarfFile::emitAbbrevs(MCSection *Section) { Abbrevs.Emit(Asm, Section); }
// Emit strings into a string section.
void DwarfFile::emitStrings(MCSection *StrSection, MCSection *OffsetSection) {
StrPool.emit(*Asm, StrSection, OffsetSection);
}
bool DwarfFile::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
const DILocalVariable *DV = Var->getVariable();
// Variables with positive arg numbers are parameters.
if (unsigned ArgNum = DV->getArg()) {
// Keep all parameters in order at the start of the variable list to ensure
// function types are correct (no out-of-order parameters)
//
// This could be improved by only doing it for optimized builds (unoptimized
// builds have the right order to begin with), searching from the back (this
// would catch the unoptimized case quickly), or doing a binary search
// rather than linear search.
auto I = Vars.begin();
while (I != Vars.end()) {
unsigned CurNum = (*I)->getVariable()->getArg();
// A local (non-parameter) variable has been found, insert immediately
// before it.
if (CurNum == 0)
break;
// A later indexed parameter has been found, insert immediately before it.
if (CurNum > ArgNum)
break;
if (CurNum == ArgNum) {
(*I)->addMMIEntry(*Var);
return false;
}
++I;
}
Vars.insert(I, Var);
return true;
}
Vars.push_back(Var);
return true;
}
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