LLVM  6.0.0svn
DwarfFile.cpp
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1 //===- llvm/CodeGen/DwarfFile.cpp - Dwarf Debug Framework -----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "DwarfFile.h"
11 #include "DwarfCompileUnit.h"
12 #include "DwarfDebug.h"
13 #include "DwarfUnit.h"
14 #include "llvm/ADT/SmallVector.h"
16 #include "llvm/CodeGen/DIE.h"
18 #include "llvm/MC/MCStreamer.h"
19 #include <algorithm>
20 #include <cstdint>
21 
22 using namespace llvm;
23 
25  : Asm(AP), Abbrevs(AbbrevAllocator), StrPool(DA, *Asm, Pref) {}
26 
27 void DwarfFile::addUnit(std::unique_ptr<DwarfCompileUnit> U) {
28  CUs.push_back(std::move(U));
29 }
30 
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);
36 }
37 
38 void DwarfFile::emitUnit(DwarfUnit *TheU, bool UseOffsets) {
39  DIE &Die = TheU->getUnitDie();
40  MCSection *USection = TheU->getSection();
41  Asm->OutStreamer->SwitchSection(USection);
42 
43  TheU->emitHeader(UseOffsets);
44 
45  Asm->emitDwarfDIE(Die);
46 }
47 
48 // Compute the size and offset for each DIE.
50  // Offset from the first CU in the debug info section is 0 initially.
51  unsigned SecOffset = 0;
52 
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());
58  }
59 }
60 
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
65 
66  // The return value here is CU-relative, after laying out
67  // all of the CU DIE.
68  return computeSizeAndOffset(TheU->getUnitDie(), Offset);
69 }
70 
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);
75 }
76 
77 void DwarfFile::emitAbbrevs(MCSection *Section) { Abbrevs.Emit(Asm, Section); }
78 
79 // Emit strings into a string section.
80 void DwarfFile::emitStrings(MCSection *StrSection, MCSection *OffsetSection) {
81  StrPool.emit(*Asm, StrSection, OffsetSection);
82 }
83 
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)
91  //
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
100  // before it.
101  if (CurNum == 0)
102  break;
103  // A later indexed parameter has been found, insert immediately before it.
104  if (CurNum > ArgNum)
105  break;
106  if (CurNum == ArgNum) {
107  (*I)->addMMIEntry(*Var);
108  return false;
109  }
110  ++I;
111  }
112  Vars.insert(I, Var);
113  return true;
114  }
115 
116  Vars.push_back(Var);
117  return true;
118 }
Instances of this class represent a uniqued identifier for a section in the current translation unit...
Definition: MCSection.h:39
void addUnit(std::unique_ptr< DwarfCompileUnit > U)
Add a unit to the list of CUs.
Definition: DwarfFile.cpp:27
virtual unsigned getHeaderSize() const
Compute the size of a header for this unit, not including the initial length field.
Definition: DwarfUnit.h:279
std::unique_ptr< MCStreamer > OutStreamer
This is the MCStreamer object for the file we are generating.
Definition: AsmPrinter.h:92
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
unsigned computeSizeAndOffset(DIE &Die, unsigned Offset)
Compute the size and offset of a DIE given an incoming Offset.
Definition: DwarfFile.cpp:73
void emitStrings(MCSection *StrSection, MCSection *OffsetSection=nullptr)
Emit all of the strings to the section given.
Definition: DwarfFile.cpp:80
LexicalScope - This class is used to track scope information.
Definition: LexicalScopes.h:45
void emitDwarfDIE(const DIE &Die) const
Recursively emit Dwarf DIE tree.
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:42
virtual void emitHeader(bool UseOffsets)=0
Emit the header for this unit, not including the initial length field.
This class is used to track local variable information.
Definition: DwarfDebug.h:76
const DILocalVariable * getVariable() const
Definition: DwarfDebug.h:124
unsigned computeSizeAndOffsetsForUnit(DwarfUnit *TheU)
Compute the size and offset of all the DIEs in the given unit.
Definition: DwarfFile.cpp:61
This dwarf writer support class manages information associated with a source file.
Definition: DwarfUnit.h:68
void emitUnit(DwarfUnit *U, bool UseOffsets)
Emit the given unit to its section.
Definition: DwarfFile.cpp:38
Allocate memory in an ever growing pool, as if by bump-pointer.
Definition: Allocator.h:138
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator begin()
Definition: SmallVector.h:116
A structured debug information entry.
Definition: DIE.h:662
DIE & getUnitDie()
Definition: DIE.h:834
This class is intended to be used as a driving class for all asm writers.
Definition: AsmPrinter.h:77
void computeSizeAndOffsets()
Compute the size and offset of all the DIEs.
Definition: DwarfFile.cpp:49
bool addScopeVariable(LexicalScope *LS, DbgVariable *Var)
Definition: DwarfFile.cpp:84
DwarfFile(AsmPrinter *AP, StringRef Pref, BumpPtrAllocator &DA)
Definition: DwarfFile.cpp:24
unsigned computeOffsetsAndAbbrevs(const AsmPrinter *AP, DIEAbbrevSet &AbbrevSet, unsigned CUOffset)
Compute the offset of this DIE and all its children.
Definition: DIE.cpp:276
MCSection * getSection() const
Return the section that this DIEUnit will be emitted into.
Definition: DIE.h:827
iterator insert(iterator I, T &&Elt)
Definition: SmallVector.h:482
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator end()
Definition: SmallVector.h:120
#define I(x, y, z)
Definition: MD5.cpp:58
void emit(AsmPrinter &Asm, MCSection *StrSection, MCSection *OffsetSection=nullptr)
void emitAbbrevs(MCSection *)
Emit a set of abbreviations to the specific section.
Definition: DwarfFile.cpp:77
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
void Emit(const AsmPrinter *AP, MCSection *Section) const
Print all abbreviations using the specified asm printer.
Definition: DIE.cpp:169
void emitUnits(bool UseOffsets)
Emit all of the units to the section listed with the given abbreviation section.
Definition: DwarfFile.cpp:33