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[llvm] Prevent duplicate files in debug line header in dwarf 5. 

Summary:

Motivation: In previous dwarf versions, file name indexes started from 1, and
the primary source file was not explicit. Dwarf 5 standard (6.2.4) prescribes
the primary source file to be explicitly given an entry with an index number 0.

The current implementation honors the specification by just duplicating the
main source file, once with index number 0, and later maybe with another
index number. While this is compliant with the letter of the standard, the
duplication causes problems for consumers of this information such as lldb.
(Some files are duplicated, where only some of them have a line table although
all refer to the same file)

With this change, dwarf 5 debug line section files always start from 0, and
the zeroth entry is not duplicated whenever possible. This requires different
handling of dwarf 4 and dwarf 5 during generation (e.g. when a function returns
an index zero for a file name, it signals an error in dwarf 4, but not in dwarf 5)
However, I think the minor complication is worth it, because it enables all
consumers (lldb, gdb, dwarfdump, objdump, and so on) to treat all files in the
file name list homogenously.

Reviewers: dblaikie, probinson, aprantl, espindola

Reviewed By: probinson

Subscribers: emaste, jvesely, nhaehnle, aprantl, javed.absar, arichardson, hiraditya, MaskRay, rupprecht, jdoerfert, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D59515

llvm-svn: 356941
This commit is contained in:
Ali Tamur 2019-03-25 20:08:00 +00:00
parent cefafc4999
commit 312ab05887
14 changed files with 70 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
llvm/include/llvm/DebugInfo/DWARF/DWARFDebugLine.h
View File

@ -275,6 +275,8 @@ public:
SequenceVector Sequences;
private:
const llvm::DWARFDebugLine::FileNameEntry &
getFileNameEntry(uint64_t Index) const;
uint32_t findRowInSeq(const DWARFDebugLine::Sequence &Seq,
object::SectionedAddress Address) const;
Optional<StringRef>

2
llvm/include/llvm/MC/MCContext.h
View File

@ -521,7 +521,7 @@ namespace llvm {
}
MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) {
return MCDwarfLineTablesCUMap[CUID];
return MCDwarfLineTablesCUMap.emplace(CUID, DwarfVersion).first->second;
}
const MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) const {

18
llvm/include/llvm/MC/MCDwarf.h
View File

@ -218,9 +218,11 @@ struct MCDwarfLineTableHeader {
private:
bool HasAllMD5 = true;
bool HasAnyMD5 = false;
unsigned DwarfVersion;
public:
MCDwarfLineTableHeader() = default;
explicit MCDwarfLineTableHeader(unsigned DwarfVersion) :
DwarfVersion(DwarfVersion) {}
Expected<unsigned> tryGetFile(StringRef &Directory, StringRef &FileName,
MD5::MD5Result *Checksum,
@ -245,6 +247,17 @@ public:
return MCDwarfFiles.empty() || (HasAllMD5 == HasAnyMD5);
}
void setRootFile(StringRef Directory, StringRef FileName,
MD5::MD5Result *Checksum, Optional<StringRef> Source) {
CompilationDir = Directory;
RootFile.Name = FileName;
RootFile.DirIndex = 0;
RootFile.Checksum = Checksum;
RootFile.Source = Source;
trackMD5Usage(Checksum);
HasSource = Source.hasValue();
}
private:
void emitV2FileDirTables(MCStreamer *MCOS) const;
void emitV5FileDirTables(MCStreamer *MCOS, Optional<MCDwarfLineStr> &LineStr,
@ -255,6 +268,8 @@ class MCDwarfDwoLineTable {
MCDwarfLineTableHeader Header;
public:
MCDwarfDwoLineTable(unsigned DwarfVersion) : Header(DwarfVersion) {}
void maybeSetRootFile(StringRef Directory, StringRef FileName,
MD5::MD5Result *Checksum, Optional<StringRef> Source) {
if (!Header.RootFile.Name.empty())
@ -282,6 +297,7 @@ class MCDwarfLineTable {
MCLineSection MCLineSections;
public:
MCDwarfLineTable(unsigned DwarfVersion) : Header(DwarfVersion) {}
// This emits the Dwarf file and the line tables for all Compile Units.
static void Emit(MCObjectStreamer *MCOS, MCDwarfLineTableParams Params);

1
llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
View File

@ -101,6 +101,7 @@ class DwarfCompileUnit final : public DwarfUnit {
}
public:
unsigned getDwarfVersion() const { return DD->getDwarfVersion(); }
DwarfCompileUnit(unsigned UID, const DICompileUnit *Node, AsmPrinter *A,
DwarfDebug *DW, DwarfFile *DWU);

1
llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
View File

@ -319,6 +319,7 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
: DebugHandlerBase(A), DebugLocs(A->OutStreamer->isVerboseAsm()),
InfoHolder(A, "info_string", DIEValueAllocator),
SkeletonHolder(A, "skel_string", DIEValueAllocator),
SplitTypeUnitFileTable(A->getDwarfVersion()),
IsDarwin(A->TM.getTargetTriple().isOSDarwin()) {
const Triple &TT = Asm->TM.getTargetTriple();

1
llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
View File

@ -397,7 +397,6 @@ void DwarfUnit::addSourceLine(DIE &Die, unsigned Line, const DIFile *File) {
return;
unsigned FileID = getOrCreateSourceID(File);
assert(FileID && "Invalid file id");
addUInt(Die, dwarf::DW_AT_decl_file, None, FileID);
addUInt(Die, dwarf::DW_AT_decl_line, None, Line);
}

20
llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
View File

@ -1017,14 +1017,28 @@ bool DWARFDebugLine::LineTable::lookupAddressRangeImpl(
}
bool DWARFDebugLine::LineTable::hasFileAtIndex(uint64_t FileIndex) const {
return FileIndex != 0 && FileIndex <= Prologue.FileNames.size();
uint16_t DwarfVersion = Prologue.getVersion();
assert(DwarfVersion != 0 && "LineTable has no dwarf version information");
if (DwarfVersion >= 5)
return FileIndex < Prologue.FileNames.size();
else
return FileIndex != 0 && FileIndex <= Prologue.FileNames.size();
}
const llvm::DWARFDebugLine::FileNameEntry &
DWARFDebugLine::LineTable::getFileNameEntry(uint64_t Index) const {
uint16_t DwarfVersion = Prologue.getVersion();
assert(DwarfVersion != 0 && "LineTable has no dwarf version information");
if (DwarfVersion >= 5)
return Prologue.FileNames[Index];
else
return Prologue.FileNames[Index - 1];
}
Optional<StringRef> DWARFDebugLine::LineTable::getSourceByIndex(uint64_t FileIndex,
FileLineInfoKind Kind) const {
if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
return None;
const FileNameEntry &Entry = Prologue.FileNames[FileIndex - 1];
const FileNameEntry &Entry = getFileNameEntry(FileIndex);
if (Optional<const char *> source = Entry.Source.getAsCString())
return StringRef(*source);
return None;
@ -1044,7 +1058,7 @@ bool DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex,
std::string &Result) const {
if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
return false;
const FileNameEntry &Entry = Prologue.FileNames[FileIndex - 1];
const FileNameEntry &Entry = getFileNameEntry(FileIndex);
StringRef FileName = Entry.Name.getAsCString().getValue();
if (Kind != FileLineInfoKind::AbsoluteFilePath ||
isPathAbsoluteOnWindowsOrPosix(FileName)) {

5
llvm/lib/MC/MCContext.cpp
View File

@ -603,7 +603,8 @@ Expected<unsigned> MCContext::getDwarfFile(StringRef Directory,
MD5::MD5Result *Checksum,
Optional<StringRef> Source,
unsigned CUID) {
MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
MCDwarfLineTable &Table =
MCDwarfLineTablesCUMap.emplace(CUID, DwarfVersion).first->second;
return Table.tryGetFile(Directory, FileName, Checksum, Source, FileNumber);
}
@ -612,7 +613,7 @@ Expected<unsigned> MCContext::getDwarfFile(StringRef Directory,
bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
const MCDwarfLineTable &LineTable = getMCDwarfLineTable(CUID);
if (FileNumber == 0)
return getDwarfVersion() >= 5 && LineTable.hasRootFile();
return getDwarfVersion() >= 5;
if (FileNumber >= LineTable.getMCDwarfFiles().size())
return false;

11
llvm/lib/MC/MCDwarf.cpp
View File

@ -542,6 +542,15 @@ Expected<unsigned> MCDwarfLineTable::tryGetFile(StringRef &Directory,
return Header.tryGetFile(Directory, FileName, Checksum, Source, FileNumber);
}
bool isRootFile(const MCDwarfFile &RootFile, StringRef &Directory,
StringRef &FileName, MD5::MD5Result *Checksum) {
if (RootFile.Name.empty() || RootFile.Name != FileName.data())
return false;
if (!RootFile.Checksum)
return !Checksum;
return *RootFile.Checksum == *Checksum;
}
Expected<unsigned>
MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
StringRef &FileName,
@ -561,6 +570,8 @@ MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
trackMD5Usage(Checksum);
HasSource = (Source != None);
}
if (isRootFile(RootFile, Directory, FileName, Checksum) && DwarfVersion >= 5)
return 0;
if (FileNumber == 0) {
// File numbers start with 1 and/or after any file numbers
// allocated by inline-assembler .file directives.

17
llvm/test/MC/ARM/dwarf-asm-multiple-sections.s
View File

@ -2,9 +2,9 @@
// RUN: llvm-dwarfdump -v %t | FileCheck -check-prefix DWARF -check-prefix DWARF45 %s
// RUN: llvm-dwarfdump --debug-line %t | FileCheck -check-prefix DWARF-DL -check-prefix DWARF-DL-5 -DDWVER=5 -DDWFILE=0 %s
// RUN: llvm-objdump -r %t | FileCheck -check-prefix RELOC -check-prefix RELOC5 %s
// RUN: llvm-mc < %s -triple=armv7-linux-gnueabi -filetype=obj -o %t -g -fdebug-compilation-dir=/tmp
// RUN: llvm-mc < %s -triple=armv7-linux-gnueabi -filetype=obj -o %t -g -dwarf-version 4 -fdebug-compilation-dir=/tmp
// RUN: llvm-dwarfdump -v %t | FileCheck -check-prefix DWARF -check-prefix DWARF45 %s
// RUN: llvm-dwarfdump --debug-line %t | FileCheck -check-prefix DWARF-DL -DDWVER=4 -DDWFILE=1 %s
// RUN: llvm-dwarfdump --debug-line %t | FileCheck -check-prefix DWARF-DL -check-prefix DWARF-DL-4 -DDWVER=4 -DDWFILE=1 %s
// RUN: llvm-objdump -r %t | FileCheck -check-prefix RELOC -check-prefix RELOC4 %s
// RUN: llvm-mc < %s -triple=armv7-linux-gnueabi -filetype=obj -o %t -g -dwarf-version 3 -fdebug-compilation-dir=/tmp
// RUN: llvm-dwarfdump -v %t | FileCheck -check-prefix DWARF -check-prefix DWARF3 %s
@ -57,11 +57,14 @@ b:
// DWARF-DL-5: include_directories[ 0] = "/tmp"
// DWARF-DL: file_names[ [[DWFILE]]]:
// DWARF-DL: name: "{{(<stdin>|-)}}"
// DWARF-DL: 0x0000000000000000 17 0 1 0 0 is_stmt
// DWARF-DL-NEXT: 0x0000000000000004 17 0 1 0 0 is_stmt end_sequence
// DWARF-DL-NEXT: 0x0000000000000000 21 0 1 0 0 is_stmt
// DWARF-DL-NEXT: 0x0000000000000004 21 0 1 0 0 is_stmt end_sequence
// DWARF-DL-5: 0x0000000000000000 17 0 0 0 0 is_stmt
// DWARF-DL-5-NEXT: 0x0000000000000004 17 0 0 0 0 is_stmt end_sequence
// DWARF-DL-5-NEXT: 0x0000000000000000 21 0 0 0 0 is_stmt
// DWARF-DL-5-NEXT: 0x0000000000000004 21 0 0 0 0 is_stmt end_sequence
// DWARF-DL-4: 0x0000000000000000 17 0 1 0 0 is_stmt
// DWARF-DL-4-NEXT: 0x0000000000000004 17 0 1 0 0 is_stmt end_sequence
// DWARF-DL-4-NEXT: 0x0000000000000000 21 0 1 0 0 is_stmt
// DWARF-DL-4-NEXT: 0x0000000000000004 21 0 1 0 0 is_stmt end_sequence
// DWARF: .debug_ranges contents:
// DWARF: 00000000 ffffffff 00000000

3
llvm/test/MC/ELF/debug-mixed-md5.ll
View File

@ -1,8 +1,7 @@
; RUN: %llc_dwarf -filetype=asm -dwarf-version=5 %s -o - | FileCheck %s -check-prefix=ASM
; RUN: %llc_dwarf -filetype=obj -dwarf-version=5 %s -o - | llvm-dwarfdump -debug-line - | FileCheck %s -check-prefix=OBJ
; ASM: .file 0 "{{.+}}" md5
; ASM: .file 1 "{{.+}}" md5
; ASM: .file 2 "t1.cpp"
; ASM: .file 1 "t1.cpp"
; ASM-NOT: md5
; OBJ: file_names[ 0]:
; OBJ-NOT: md5

6
llvm/test/MC/ELF/dwarf-file0.s
View File

@ -19,16 +19,14 @@
# CHECK: file_names[ 1]:
# CHECK-NEXT: name: "header.h"
# CHECK-NEXT: dir_index: 1
# CHECK: file_names[ 2]:
# CHECK-NEXT: name: "root.cpp"
# CHECK-4: file_names[ 2]:
# CHECK-4-NEXT: name: "root.cpp"
# CHECK-4-NEXT: dir_index: 2
# CHECK-5-NEXT: dir_index: 0
# ASM-NOT: .file
# ASM-5: .file 0 "/test" "root.cpp"
# ASM: .file 1 "/include" "header.h"
# ASM-4: .file 2 "/test" "root.cpp"
# ASM-5: .file 2 "root.cpp"
# ASM-NOT: .file
# WARN: file 0 not supported prior to DWARF-5

BIN
llvm/test/tools/llvm-objdump/Inputs/embedded-source
View File

Binary file not shown.

9
llvm/test/tools/llvm-objdump/X86/function-sections-line-numbers.s
View File

@ -30,8 +30,7 @@
_Z2f1v: # @_Z2f1v
.Lfunc_begin0:
.file 0 "/home/avl" "test.cpp" md5 0xefae234cc05b45384d782316d3a5d338
.file 1 "test.cpp" md5 0xefae234cc05b45384d782316d3a5d338
.loc 1 1 0 # test.cpp:1:0
.loc 0 1 0 # test.cpp:1:0
.cfi_startproc
# %bb.0: # %entry
pushq %rbp
@ -40,7 +39,7 @@ _Z2f1v: # @_Z2f1v
movq %rsp, %rbp
.cfi_def_cfa_register %rbp
.Ltmp0:
.loc 1 1 12 prologue_end # test.cpp:1:12
.loc 0 1 12 prologue_end # test.cpp:1:12
popq %rbp
.cfi_def_cfa %rsp, 8
retq
@ -55,7 +54,7 @@ _Z2f1v: # @_Z2f1v
.type _Z2f2v,@function
_Z2f2v: # @_Z2f2v
.Lfunc_begin1:
.loc 1 2 0 # test.cpp:2:0
.loc 0 2 0 # test.cpp:2:0
.cfi_startproc
# %bb.0: # %entry
pushq %rbp
@ -64,7 +63,7 @@ _Z2f2v: # @_Z2f2v
movq %rsp, %rbp
.cfi_def_cfa_register %rbp
.Ltmp2:
.loc 1 2 12 prologue_end # test.cpp:2:12
.loc 0 2 12 prologue_end # test.cpp:2:12
popq %rbp
.cfi_def_cfa %rsp, 8
retq