LLVM  14.0.0git
DwarfFile.cpp
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1 //===- llvm/CodeGen/DwarfFile.cpp - Dwarf Debug Framework -----------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "DwarfFile.h"
10 #include "DwarfCompileUnit.h"
11 #include "DwarfDebug.h"
12 #include "DwarfUnit.h"
15 #include "llvm/IR/Metadata.h"
16 #include "llvm/MC/MCStreamer.h"
17 #include <algorithm>
18 #include <cstdint>
19 
20 using namespace llvm;
21 
23  : Asm(AP), Abbrevs(AbbrevAllocator), StrPool(DA, *Asm, Pref) {}
24 
25 void DwarfFile::addUnit(std::unique_ptr<DwarfCompileUnit> U) {
26  CUs.push_back(std::move(U));
27 }
28 
29 // Emit the various dwarf units to the unit section USection with
30 // the abbreviations going into ASection.
31 void DwarfFile::emitUnits(bool UseOffsets) {
32  for (const auto &TheU : CUs)
33  emitUnit(TheU.get(), UseOffsets);
34 }
35 
36 void DwarfFile::emitUnit(DwarfUnit *TheU, bool UseOffsets) {
37  if (TheU->getCUNode()->isDebugDirectivesOnly())
38  return;
39 
40  MCSection *S = TheU->getSection();
41 
42  if (!S)
43  return;
44 
45  // Skip CUs that ended up not being needed (split CUs that were abandoned
46  // because they added no information beyond the non-split CU)
47  if (llvm::empty(TheU->getUnitDie().values()))
48  return;
49 
50  Asm->OutStreamer->SwitchSection(S);
51  TheU->emitHeader(UseOffsets);
52  Asm->emitDwarfDIE(TheU->getUnitDie());
53 
54  if (MCSymbol *EndLabel = TheU->getEndLabel())
55  Asm->OutStreamer->emitLabel(EndLabel);
56 }
57 
58 // Compute the size and offset for each DIE.
60  // Offset from the first CU in the debug info section is 0 initially.
61  uint64_t SecOffset = 0;
62 
63  // Iterate over each compile unit and set the size and offsets for each
64  // DIE within each compile unit. All offsets are CU relative.
65  for (const auto &TheU : CUs) {
66  if (TheU->getCUNode()->isDebugDirectivesOnly())
67  continue;
68 
69  // Skip CUs that ended up not being needed (split CUs that were abandoned
70  // because they added no information beyond the non-split CU)
71  if (llvm::empty(TheU->getUnitDie().values()))
72  return;
73 
74  TheU->setDebugSectionOffset(SecOffset);
75  SecOffset += computeSizeAndOffsetsForUnit(TheU.get());
76  }
77  if (SecOffset > UINT32_MAX && !Asm->isDwarf64())
78  report_fatal_error("The generated debug information is too large "
79  "for the 32-bit DWARF format.");
80 }
81 
83  // CU-relative offset is reset to 0 here.
84  unsigned Offset = Asm->getUnitLengthFieldByteSize() + // Length of Unit Info
85  TheU->getHeaderSize(); // Unit-specific headers
86 
87  // The return value here is CU-relative, after laying out
88  // all of the CU DIE.
89  return computeSizeAndOffset(TheU->getUnitDie(), Offset);
90 }
91 
92 // Compute the size and offset of a DIE. The offset is relative to start of the
93 // CU. It returns the offset after laying out the DIE.
94 unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
95  return Die.computeOffsetsAndAbbrevs(Asm, Abbrevs, Offset);
96 }
97 
99 
100 // Emit strings into a string section.
101 void DwarfFile::emitStrings(MCSection *StrSection, MCSection *OffsetSection,
102  bool UseRelativeOffsets) {
103  StrPool.emit(*Asm, StrSection, OffsetSection, UseRelativeOffsets);
104 }
105 
107  auto &ScopeVars = ScopeVariables[LS];
108  const DILocalVariable *DV = Var->getVariable();
109  if (unsigned ArgNum = DV->getArg()) {
110  auto Cached = ScopeVars.Args.find(ArgNum);
111  if (Cached == ScopeVars.Args.end())
112  ScopeVars.Args[ArgNum] = Var;
113  else {
114  Cached->second->addMMIEntry(*Var);
115  return false;
116  }
117  } else {
118  ScopeVars.Locals.push_back(Var);
119  }
120  return true;
121 }
122 
124  SmallVectorImpl<DbgLabel *> &Labels = ScopeLabels[LS];
125  Labels.push_back(Label);
126 }
127 
128 std::pair<uint32_t, RangeSpanList *>
130  CURangeLists.push_back(
131  RangeSpanList{Asm->createTempSymbol("debug_ranges"), &CU, std::move(R)});
132  return std::make_pair(CURangeLists.size() - 1, &CURangeLists.back());
133 }
AsmPrinter.h
llvm
This file implements support for optimizing divisions by a constant.
Definition: AllocatorList.h:23
llvm::MCSymbol
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:41
llvm::DwarfUnit::emitHeader
virtual void emitHeader(bool UseOffsets)=0
Emit the header for this unit, not including the initial length field.
Metadata.h
DebugInfoMetadata.h
llvm::AsmPrinter::createTempSymbol
MCSymbol * createTempSymbol(const Twine &Name) const
Definition: AsmPrinter.cpp:3129
llvm::DwarfFile::DwarfFile
DwarfFile(AsmPrinter *AP, StringRef Pref, BumpPtrAllocator &DA)
Definition: DwarfFile.cpp:22
llvm::DwarfCompileUnit
Definition: DwarfCompileUnit.h:47
llvm::SmallVector
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1168
llvm::LexicalScope
LexicalScope - This class is used to track scope information.
Definition: LexicalScopes.h:44
llvm::DwarfUnit::getEndLabel
MCSymbol * getEndLabel() const
Definition: DwarfUnit.h:99
llvm::DwarfFile::addScopeVariable
bool addScopeVariable(LexicalScope *LS, DbgVariable *Var)
Definition: DwarfFile.cpp:106
Offset
uint64_t Offset
Definition: ELFObjHandler.cpp:81
llvm::DIE
A structured debug information entry.
Definition: DIE.h:739
llvm::DbgLabel
This class is used to track label information.
Definition: DwarfDebug.h:233
llvm::DIEValueList::values
value_range values()
Definition: DIE.h:727
llvm::DwarfFile::computeSizeAndOffset
unsigned computeSizeAndOffset(DIE &Die, unsigned Offset)
Compute the size and offset of a DIE given an incoming Offset.
Definition: DwarfFile.cpp:94
llvm::ARMBuildAttrs::Section
@ Section
Legacy Tags.
Definition: ARMBuildAttributes.h:78
DwarfFile.h
llvm::DwarfFile::emitUnit
void emitUnit(DwarfUnit *TheU, bool UseOffsets)
Emit the given unit to its section.
Definition: DwarfFile.cpp:36
llvm::DILocalVariable
Local variable.
Definition: DebugInfoMetadata.h:3097
llvm::AsmPrinter::OutStreamer
std::unique_ptr< MCStreamer > OutStreamer
This is the MCStreamer object for the file we are generating.
Definition: AsmPrinter.h:96
llvm::DwarfUnit::getCUNode
const DICompileUnit * getCUNode() const
Definition: DwarfUnit.h:101
llvm::BasicBlockSection::Labels
@ Labels
llvm::M68kBeads::DA
@ DA
Definition: M68kBaseInfo.h:59
llvm::report_fatal_error
void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:140
llvm::DwarfFile::addRange
std::pair< uint32_t, RangeSpanList * > addRange(const DwarfCompileUnit &CU, SmallVector< RangeSpan, 2 > R)
Definition: DwarfFile.cpp:129
llvm::DwarfFile::emitStrings
void emitStrings(MCSection *StrSection, MCSection *OffsetSection=nullptr, bool UseRelativeOffsets=false)
Emit all of the strings to the section given.
Definition: DwarfFile.cpp:101
llvm::DIEAbbrevSet::Emit
void Emit(const AsmPrinter *AP, MCSection *Section) const
Print all abbreviations using the specified asm printer.
Definition: DIE.cpp:170
DwarfDebug.h
llvm::DbgVariable
This class is used to track local variable information.
Definition: DwarfDebug.h:116
llvm::DILocalVariable::getArg
unsigned getArg() const
Definition: DebugInfoMetadata.h:3158
uint64_t
llvm::BumpPtrAllocatorImpl
Allocate memory in an ever growing pool, as if by bump-pointer.
Definition: Allocator.h:67
move
compiles ldr LCPI1_0 ldr ldr mov lsr tst moveq r1 ldr LCPI1_1 and r0 bx lr It would be better to do something like to fold the shift into the conditional move
Definition: README.txt:546
llvm::DIEUnit::getSection
MCSection * getSection() const
Return the section that this DIEUnit will be emitted into.
Definition: DIE.h:908
llvm::DICompileUnit::isDebugDirectivesOnly
bool isDebugDirectivesOnly() const
Definition: DebugInfoMetadata.h:1471
llvm::DwarfFile::computeSizeAndOffsetsForUnit
unsigned computeSizeAndOffsetsForUnit(DwarfUnit *TheU)
Compute the size and offset of all the DIEs in the given unit.
Definition: DwarfFile.cpp:82
llvm::DwarfFile::addScopeLabel
void addScopeLabel(LexicalScope *LS, DbgLabel *Label)
Definition: DwarfFile.cpp:123
llvm::StringRef
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:58
llvm::DwarfStringPool::emit
void emit(AsmPrinter &Asm, MCSection *StrSection, MCSection *OffsetSection=nullptr, bool UseRelativeOffsets=false)
Definition: DwarfStringPool.cpp:75
llvm::MCSection
Instances of this class represent a uniqued identifier for a section in the current translation unit.
Definition: MCSection.h:39
S
add sub stmia L5 ldr r0 bl L_printf $stub Instead of a and a wouldn t it be better to do three moves *Return an aggregate type is even return S
Definition: README.txt:210
DwarfCompileUnit.h
llvm::AsmPrinter::getUnitLengthFieldByteSize
unsigned int getUnitLengthFieldByteSize() const
Returns 4 for DWARF32 and 12 for DWARF64.
Definition: AsmPrinter.cpp:3635
llvm::DwarfFile::addUnit
void addUnit(std::unique_ptr< DwarfCompileUnit > U)
Add a unit to the list of CUs.
Definition: DwarfFile.cpp:25
llvm::DwarfFile::computeSizeAndOffsets
void computeSizeAndOffsets()
Compute the size and offset of all the DIEs.
Definition: DwarfFile.cpp:59
llvm::empty
constexpr bool empty(const T &RangeOrContainer)
Test whether RangeOrContainer is empty. Similar to C++17 std::empty.
Definition: STLExtras.h:254
llvm::AsmPrinter::isDwarf64
bool isDwarf64() const
Definition: AsmPrinter.cpp:3626
llvm::AArch64CC::LS
@ LS
Definition: AArch64BaseInfo.h:264
DwarfUnit.h
llvm::AsmPrinter
This class is intended to be used as a driving class for all asm writers.
Definition: AsmPrinter.h:81
llvm::DwarfFile::emitUnits
void emitUnits(bool UseOffsets)
Emit all of the units to the section listed with the given abbreviation section.
Definition: DwarfFile.cpp:31
MCStreamer.h
llvm::DbgVariable::getVariable
const DILocalVariable * getVariable() const
Definition: DwarfDebug.h:167
llvm::SmallVectorImpl
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:43
llvm::HexStyle::Asm
@ Asm
0ffh
Definition: MCInstPrinter.h:34
llvm::AsmPrinter::emitDwarfDIE
void emitDwarfDIE(const DIE &Die) const
Recursively emit Dwarf DIE tree.
Definition: AsmPrinterDwarf.cpp:283
llvm::DwarfUnit
This dwarf writer support class manages information associated with a source file.
Definition: DwarfUnit.h:37
llvm::DIE::computeOffsetsAndAbbrevs
unsigned computeOffsetsAndAbbrevs(const AsmPrinter *AP, DIEAbbrevSet &AbbrevSet, unsigned CUOffset)
Compute the offset of this DIE and all its children.
Definition: DIE.cpp:277
llvm::DwarfFile::emitAbbrevs
void emitAbbrevs(MCSection *)
Emit a set of abbreviations to the specific section.
Definition: DwarfFile.cpp:98
llvm::DbgVariable::addMMIEntry
void addMMIEntry(const DbgVariable &V)
Definition: DwarfDebug.cpp:293
CU
Definition: AArch64AsmBackend.cpp:501
llvm::RangeSpanList
Definition: DwarfFile.h:41
llvm::DIEUnit::getUnitDie
DIE & getUnitDie()
Definition: DIE.h:911
llvm::DwarfUnit::getHeaderSize
virtual unsigned getHeaderSize() const
Compute the size of a header for this unit, not including the initial length field.
Definition: DwarfUnit.h:268