This patch adds support of DWARFv5 .debug_rnglists table.
As DWARFLinker resolves relocations, it is able to always
use DW_FORM_addr instead of DW_FORM_addrx. DW_FORM_addrx
helps to minimize number of relocations, it is also used for
split DWARF. Both of these cases are not relevant for the
DWARFLinker. Thus, this patch converts all DW_FORM_addrx
forms into the DW_FORM_addr. And, as the result, it converts
range lists of DW_FORM_rnglistx form into the DW_FORM_sec_offset.
For the --update case all DW_FORM_addrx, DW_FORM_rnglistx
are preserved as is.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D143903
As a preparation for implementing DWARFv5 address ranges generation,
this patch refactors existing address ranges generation code:
Split emitUnitRangesEntries into two functions emitDwarfDebugArangesTable
and emitDwarfDebugRangesTableFragment. Use AddressRanges to prepare linked
address ranges. Refactor Unit.getLowPc(), to use std::nullopt as undefined value.
Reviewed By: JDevlieghere
Differential Revision: https://reviews.llvm.org/D141943
Verify that every DIE that's marked as kept, has a parent that's kept as
well. This invariant should always hold and is easy to verify when
asserts are enabled.
Differential revision: https://reviews.llvm.org/D140227
To improve deduplication across CUs within a single object file,
2b747241a6a0 changed the way we track ODR canonical candidates. The
result is that some assumptions no longer hold. Because of the
aforementioned change, the following condition
assert(Ref > InputDIE.getOffset());
in DWARFLinker::DIECloner::cloneDieReferenceAttribute is no longer an
invariant. An example of a situation where this assertion no longer
holds is when we have decided to replace a backward reference in the
current CU with a forward reference in a subsequent CU. The ODR
canonical DIE hasn't been emitted yet, but the references DIE has an
offset smaller than the current DIE. The assertion is only true if the
referenced DIE was the ODR canonical DIE, which is no longer guaranteed
to be part of the same CU.
Big thanks to Alexey for putting a test together.
Differential revision: https://reviews.llvm.org/D138176
DWARF files may contain overlapping address ranges. f.e. it can happen if the two
copies of the function have identical instruction sequences and they end up sharing.
That looks incorrect from the point of view of DWARF spec. Current implementation
of DWARFLinker does not combine overlapped address ranges. It would be good if such
ranges would be handled in some useful way. Thus, this patch allows DWARFLinker
to combine overlapped ranges in a single one.
Depends on D86539
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D123469
DWARF files may contain overlapping address ranges. f.e. it can happen if the two
copies of the function have identical instruction sequences and they end up sharing.
That looks incorrect from the point of view of DWARF spec. Current implementation
of DWARFLinker does not combine overlapped address ranges. It would be good if such
ranges would be handled in some useful way. Thus, this patch allows DWARFLinker
to combine overlapped ranges in a single one.
Depends on D86539
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D123469
This patch implements proposal https://lists.llvm.org/pipermail/llvm-dev/2020-August/144579.html
llvm-dwarfutil - is a tool that is used for processing debug info(DWARF) located in built binary files to improve debug info quality, reduce debug info size. The patch currently implements smaller set of command-line options(comparing to the proposal):
```
./llvm-dwarfutil [options] <input file> <output file>
--garbage-collection Do garbage collection for debug info(default)
-j <value> Alias for --num-threads
--no-garbage-collection Don`t do garbage collection for debug info
--no-odr-deduplication Don`t do ODR deduplication for debug types
--no-odr Alias for --no-odr-deduplication
--no-separate-debug-file
Create single output file, containing debug tables(default)
--num-threads <threads> Number of available threads for multi-threaded execution. Defaults to the number of cores on the current machine
--odr-deduplication Do ODR deduplication for debug types(default)
--odr Alias for --odr-deduplication
--separate-debug-file Create two output files: file w/o debug tables and file with debug tables
--tombstone [bfd,maxpc,exec,universal]
Tombstone value used as a marker of invalid address(default: universal)
=bfd - Zero for all addresses and [1,1] for DWARF v4 (or less) address ranges and exec
=maxpc - Minus 1 for all addresses and minus 2 for DWARF v4 (or less) address ranges
=exec - Match with address ranges of executable sections
=universal - Both: bfd and maxpc
```
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D86539
This patch implements proposal https://lists.llvm.org/pipermail/llvm-dev/2020-August/144579.html
llvm-dwarfutil - is a tool that is used for processing debug info(DWARF) located in built binary files to improve debug info quality, reduce debug info size. The patch currently implements smaller set of command-line options(comparing to the proposal):
```
./llvm-dwarfutil [options] <input file> <output file>
--garbage-collection Do garbage collection for debug info(default)
-j <value> Alias for --num-threads
--no-garbage-collection Don`t do garbage collection for debug info
--no-odr-deduplication Don`t do ODR deduplication for debug types
--no-odr Alias for --no-odr-deduplication
--no-separate-debug-file
Create single output file, containing debug tables(default)
--num-threads <threads> Number of available threads for multi-threaded execution. Defaults to the number of cores on the current machine
--odr-deduplication Do ODR deduplication for debug types(default)
--odr Alias for --odr-deduplication
--separate-debug-file Create two output files: file w/o debug tables and file with debug tables
--tombstone [bfd,maxpc,exec,universal]
Tombstone value used as a marker of invalid address(default: universal)
=bfd - Zero for all addresses and [1,1] for DWARF v4 (or less) address ranges and exec
=maxpc - Minus 1 for all addresses and minus 2 for DWARF v4 (or less) address ranges
=exec - Match with address ranges of executable sections
=universal - Both: bfd and maxpc
```
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D86539
This patch is extracted from D86539.
Current implementation of lookForDIEsToKeep() function skips types
duplications basing on the getCanonicalDIEOffset() data:
```
if (AttrSpec.Form != dwarf::DW_FORM_ref_addr && (UseOdr || IsModuleRef) &&
Info.Ctxt &&
Info.Ctxt != ReferencedCU->getInfo(Info.ParentIdx).Ctxt &&
Info.Ctxt->getCanonicalDIEOffset() && isODRAttribute(AttrSpec.Attr)) <<<<<
continue;
```
But that field is set after all compile units inside object file are processed:
```
for (auto &CurrentUnit : OptContext.CompileUnits)
lookForDIEsToKeep(.., &CurrentUnit, ..); // check CanonicalDIEOffset
DIECloner.cloneAllCompileUnits(); // set CanonicalDIEOffset
```
Thus, if the object file contains several compilation units - types would
not be deduplicated. The above solution works well for the case when the object file
contains only one compilation unit. But if the object file contains several compilation
units then types would not be deduplicated between these compilation units.
This patch changes the algorithm so that types were deduplicated between
compilation units from the same object file.
It produces binary incompatible output for the cases when several compilation units
are located inside the same object file.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D125469
Currently dsymutil will silently fail when processing binaries with
Dwarf 5 debug info. This patch adds rudimentary support for Dwarf 5 in
dsymutil.
- Recognize relocations in the debug_addr section.
- Recognize (a subset of) Dwarf 5 form values.
- Emits valid Dwarf 5 compile unit header chains.
To simplify things (and avoid having to emit indexed sections) I decided
to emit the relocated addresses directly in the debug info section.
- DW_FORM_strx gets relocated and rewritten to DW_FORM_strp
- DW_FORM_addrx gets relocated and rewritten to DW_FORM_addr
Obviously there's a lot of work left, but this should be a step in the
right direction.
rdar://62345491
Differential revision: https://reviews.llvm.org/D94323
This patch fixes a bug that would cause dsymutil to collect
.swiftinterface files for the Swift stdlib and other SDK
modules. There is no advantage in copying these since they should be
loaded from the ones bundled with LLDB's embedded Swift compiler
instead and copying them will cause LLDB to recompile them from source
instead of loading their prebuilt cached counterparts in the SDK.
rdar://problem/57463247
Differential Revisions: https://reviews.llvm.org/D75196
Summary:
This patch relands D71271. The problem with D71271 is that it has cyclic dependency:
CodeGen->AsmPrinter->DebugInfoDWARF->CodeGen. To avoid cyclic dependency this patch
puts implementation for DWARFOptimizer into separate library: lib/DWARFLinker.
Thus the difference between this patch and D71271 is in that DWARFOptimizer renamed into
DWARFLinker and it`s files are put into lib/DWARFLinker.
Reviewers: JDevlieghere, friss, dblaikie, aprantl
Reviewed By: JDevlieghere
Subscribers: thegameg, merge_guards_bot, probinson, mgorny, hiraditya, llvm-commits
Tags: #llvm, #debug-info
Differential Revision: https://reviews.llvm.org/D71839
