1 //===- llvm/CodeGen/DwarfFile.cpp - Dwarf Debug Framework -----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "DwarfFile.h"
11 #include "DwarfCompileUnit.h"
12 #include "DwarfDebug.h"
13 #include "DwarfUnit.h"
14 #include "llvm/ADT/SmallVector.h"
15 #include "llvm/CodeGen/AsmPrinter.h"
16 #include "llvm/CodeGen/DIE.h"
17 #include "llvm/IR/DebugInfoMetadata.h"
18 #include "llvm/MC/MCStreamer.h"
24 DwarfFile::DwarfFile(AsmPrinter *AP, StringRef Pref, BumpPtrAllocator &DA)
25 : Asm(AP), Abbrevs(AbbrevAllocator), StrPool(DA, *Asm, Pref) {}
27 void DwarfFile::addUnit(std::unique_ptr<DwarfCompileUnit> U) {
28 CUs.push_back(std::move(U));
31 // Emit the various dwarf units to the unit section USection with
32 // the abbreviations going into ASection.
33 void DwarfFile::emitUnits(bool UseOffsets) {
34 for (const auto &TheU : CUs)
35 emitUnit(TheU.get(), UseOffsets);
38 void DwarfFile::emitUnit(DwarfUnit *TheU, bool UseOffsets) {
39 DIE &Die = TheU->getUnitDie();
40 MCSection *USection = TheU->getSection();
41 Asm->OutStreamer->SwitchSection(USection);
43 TheU->emitHeader(UseOffsets);
45 Asm->emitDwarfDIE(Die);
48 // Compute the size and offset for each DIE.
49 void DwarfFile::computeSizeAndOffsets() {
50 // Offset from the first CU in the debug info section is 0 initially.
51 unsigned SecOffset = 0;
53 // Iterate over each compile unit and set the size and offsets for each
54 // DIE within each compile unit. All offsets are CU relative.
55 for (const auto &TheU : CUs) {
56 TheU->setDebugSectionOffset(SecOffset);
57 SecOffset += computeSizeAndOffsetsForUnit(TheU.get());
61 unsigned DwarfFile::computeSizeAndOffsetsForUnit(DwarfUnit *TheU) {
62 // CU-relative offset is reset to 0 here.
63 unsigned Offset = sizeof(int32_t) + // Length of Unit Info
64 TheU->getHeaderSize(); // Unit-specific headers
66 // The return value here is CU-relative, after laying out
68 return computeSizeAndOffset(TheU->getUnitDie(), Offset);
71 // Compute the size and offset of a DIE. The offset is relative to start of the
72 // CU. It returns the offset after laying out the DIE.
73 unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
74 return Die.computeOffsetsAndAbbrevs(Asm, Abbrevs, Offset);
77 void DwarfFile::emitAbbrevs(MCSection *Section) { Abbrevs.Emit(Asm, Section); }
79 // Emit strings into a string section.
80 void DwarfFile::emitStrings(MCSection *StrSection, MCSection *OffsetSection) {
81 StrPool.emit(*Asm, StrSection, OffsetSection);
84 bool DwarfFile::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
85 SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
86 const DILocalVariable *DV = Var->getVariable();
87 // Variables with positive arg numbers are parameters.
88 if (unsigned ArgNum = DV->getArg()) {
89 // Keep all parameters in order at the start of the variable list to ensure
90 // function types are correct (no out-of-order parameters)
92 // This could be improved by only doing it for optimized builds (unoptimized
93 // builds have the right order to begin with), searching from the back (this
94 // would catch the unoptimized case quickly), or doing a binary search
95 // rather than linear search.
96 auto I = Vars.begin();
97 while (I != Vars.end()) {
98 unsigned CurNum = (*I)->getVariable()->getArg();
99 // A local (non-parameter) variable has been found, insert immediately
103 // A later indexed parameter has been found, insert immediately before it.
106 if (CurNum == ArgNum) {
107 (*I)->addMMIEntry(*Var);