inlined subroutines for a given address.
This is essentially the hot path of llvm-symbolizer when extracting
inlined frames during symbolization. Previously, we would read every
subprogram and every inlined subroutine, building a std::map across the
entire PC space to the best DIE, and then do only a handful of queries
as we symbolized a backtrace. A huge fraction of the time was spent
building the map itself.
This patch changes it two a two-level system. First, we just build a map
from PC-interval to DWARF subprograms. These are required to be disjoint
and so constructing this is pretty easy. Second, we build a map *just*
for the inlined subroutines within the subprogram containing the query
address. This allows us to look at far fewer DIEs and build a *much*
smaller set of cached maps in the llvm-symbolizer case where only a few
address get symbolized during the entire run.
It also builds both interval maps in a very different way. It constructs
a single flat vector of pairs that maps from offset -> index. The
indices point into collections of DIE objects, but can also be
"tombstones" (-1) to mark gaps. In the case of subprograms, this mostly
just simplifies the data structure a bit. For inlined subroutines,
because we carefully split them as we build the map, we end up in many
cases having no holes and not having to store both start and stop
offsets.
Finally, the PC ranges for the inlined subroutines are compressed into
32-bits by making them relative to the base PC of the outer subprogram.
This means that if you have a single function body with over 2gb of
executable code in it, we will stop mapping address past the first 2gb
of that function into inlined subroutines and just give you the
subprogram. This doesn't seem like a problem. ;]
All of this combines to make llvm-symbolizer *well* over 2x faster for
symbolizing backtraces out of LLVM's unittests. Death-test heavy unit
tests are running >2x faster. I'm still going to look at completely
disabling symbolization there, but figured while I had a good benchmark
we should make symbolization a bit better.
Sadly, the logic to build the flat interval map for the inlined
subroutines is fairly complex. I'm not super happy about this and
welcome any simplifying suggestions.
Huge thanks to Dave Blaikie who helped walk me through what the various
things I needed to do in DWARF to make this work.
Differential Revision: https://reviews.llvm.org/D40987
llvm-svn: 321345
Reorganizes the DWARF consumer to derive the string offsets table
contribution's format from the contribution header instead of
(incorrectly) from the unit's format.
Reviewers: JDevliegehere, aprantl
Differential Revision: https://reviews.llvm.org/D41146
llvm-svn: 321295
Adds missing support for DW_FORM_data16.
Update of r320852/r320886, fixing the unittest again, this time use a
raw char string for the test data.
Differential Revision: https://reviews.llvm.org/D41090
llvm-svn: 321011
Adds missing support for DW_FORM_data16.
Update of r320852, fixing the unittest to use a hand-coded struct
instead of std::array to guarantee data layout.
Differential Revision: https://reviews.llvm.org/D41090
llvm-svn: 320886
This fixes a bug where the verifier was complaining about empty
accelerator tables. When the table is empty, its size is not a valid
offset as it points after the end of the section.
This patch also makes the extractor return llvm:Error instead of bool
for better error reporting in the verifier.
Differential revision: https://reviews.llvm.org/D41063
rdar://35932007
llvm-svn: 320399
The previous implementation would only look 1 DW_AT_specification or DW_AT_abstract_origin deep. This means DWARFDie::getName() would fail in certain cases. I ran into such a case while creating a tool that used the LLVM DWARF parser to generate a symbolication format so I have seen this in the wild.
Differential Revision: https://reviews.llvm.org/D40156
llvm-svn: 319104
DWARF4 relative DW_AT_high_pc values are now displayed as absolute
addresses. The relative value is only shown when explicitly dumping the
forms, i.e. in show-form or verbose mode.
```
DW_AT_low_pc (0x0000000000000049)
DW_AT_high_pc (0x00000019)
```
becomes
```
DW_AT_low_pc (0x0000000000000049)
DW_AT_high_pc (0x0000000000000062)
```
Differential revision: https://reviews.llvm.org/D40317
rdar://35416943
llvm-svn: 319044
As a side effect, the .debug_line section will be dumped in physical
order, rather than in the order that compile units refer to their
associated portions of the .debug_line section. These are probably
always the same order anyway, and no tests noticed the difference.
Differential Revision: https://reviews.llvm.org/D39854
llvm-svn: 318839
Patch improves next things:
* Fixes assert/crash in getOpDesc when giving it a invalid expression op code.
* DWARFExpression::print() called DWARFExpression::Operation::getEndOffset() which
returned and used uninitialized field EndOffset. Patch fixes that.
* Teaches verifier to verify DW_AT_location and error out on broken expressions.
Differential revision: https://reviews.llvm.org/D39294
llvm-svn: 316756
Add the option to lookup an address in the debug information and print
out the file, function, block and line table details.
Differential revision: https://reviews.llvm.org/D38409
llvm-svn: 316619
This fixes possible out of bound access in
DWARFDie::getFirstChild()
which might happen when .debug_info section is corrupted,
like shown in testcase.
Differential revision: https://reviews.llvm.org/D39185
llvm-svn: 316566
Currently llvm-dwarfdump runs into llvm_unreachable when
faces DW_CFA_GNU_args_size. Patch implements the support.
Differential revision: https://reviews.llvm.org/D38879
llvm-svn: 315897
This patch adds printing for DW_AT_type DIEs like it is already the case
for DW_AT_specification DIEs. This is a rather naive approach and only a
start. We should have pretty printers for different languages.
Recommit after being reverted in r315299.
Differential revision: https://reviews.llvm.org/D36993
llvm-svn: 315316
This patch adds printing for DW_AT_type DIEs like it is already the case
for DW_AT_specification DIEs. This is a rather naive approach and only a
start. We should have pretty printers for different languages.
Differential revision: https://reviews.llvm.org/D36993
llvm-svn: 315297
This patch adds two new verifiers:
- It checks that the root DIE of a CU is actually a valid unit DIE.
(based on its tag)
- For DWARF5 which contains a unit type int he CU header, it checks that
this matches the type of the unit DIE.
Differential revision: https://reviews.llvm.org/D38453
llvm-svn: 315121
The test fails on Linux; see follow-up email on the llvm-commits list.
> Add the option to lookup an address in the debug information and print
> out the file, function, block and line table details.
>
> Differential revision: https://reviews.llvm.org/D38409
This also reverts the follow-up r314818:
> [test] Fix llvm-dwarfdump/cmdline.test
>
> Fixes test/tools/llvm-dwarfdump/cmdline.test
llvm-svn: 314825
Add the option to lookup an address in the debug information and print
out the file, function, block and line table details.
Differential revision: https://reviews.llvm.org/D38409
llvm-svn: 314817
This implement the insertion operator for DWARF address ranges so they
are consistently printed as [LowPC, HighPC).
While a dump method might have felt more consistent, it is used
exclusively for printing error messages in the verifier and never used
for actual dumping. Hence this approach is more intuitive and creates
less clutter at the call sites.
Differential revision: https://reviews.llvm.org/D38395
llvm-svn: 314523
This patch introduces 3 helper functions: error(), warn() and note() to
make printing during verification more consistent. When supported, the
respective prefixes are printed in color using the same color scheme as
clang.
Differential revision: https://reviews.llvm.org/D38368
llvm-svn: 314498
This patch implements the dwarfdump option --find=<name>. This option
looks for a DIE in the accelerator tables and dumps it if found. This
initial patch only adds support for .apple_names to keep the review
small, adding the other sections and pubnames support should be
trivial though.
Differential Revision: https://reviews.llvm.org/D38282
llvm-svn: 314439
This patch adds a check to the DWARF verifier to detect CUs without a
unit DIE.
Differential revision: https://reviews.llvm.org/D38363
llvm-svn: 314426
When dsymutil generates the companion file, its strips all unnecessary
sections by omitting their body and setting the offset in their
corresponding load command to zero.
One such section is the .eh_frame section, as it contains runtime
information rather than debug information and is part of the __TEXT
segment. When reading this section, we would just read the number of
bytes specified in the load command, starting from offset 0 (i.e. the
beginning of the file).
Rather than trying to parse this obviously invalid section, dwarfdump
now skips this.
Differential revision: https://reviews.llvm.org/D38135
llvm-svn: 314208
Adrian Prantl