Commit Graph

103 Commits

Author SHA1 Message Date
David Blaikie
dfdc12ce21 llvm-dwarfdump: Don't error on mixed units using/not using str_offsets
This lead to errors when dumping binaries with v4 and v5 units linked
together (but could've also errored on v5 units that did/didn't use
str_offsets).

Also improves error handling and messages around invalid str_offsets
contributions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361683 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-25 00:07:22 +00:00
David Blaikie
ee1b58a962 dwarfdump: Deterministically... determine whether parsing a DWARF32 or DWARF64 str_offsets header
Rather than trying one and then the other - use the kind of the CU to
select which kind of header to parse.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361589 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-24 01:41:58 +00:00
David Blaikie
deeb5d51e3 dwarfdump: Add a bit more DWARF64 support
This test case was incorrect because it mixed DWARF32 and DWARF64 for a
single unit (DWARF32 unit referencing a DWARF64 str_offsets section). So
fix enough of the unit parsing for DWARF64 and make the test valid.

(not sure if anyone needs DWARF64 support though - support in
libDebugInfoDWARF has been added piecemeal and LLVM doesn't produce it
at all)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361582 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-24 01:05:52 +00:00
David Blaikie
0e902d0a63 DebugInfo/DWARF: Minor expression simplification
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360377 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-09 21:23:40 +00:00
Alexey Lapshin
a15cff122c [DebugInfo] add SectionedAddress to DebugInfo interfaces.
That patch is the fix for https://bugs.llvm.org/show_bug.cgi?id=40703
   "wrong line number info for obj file compiled with -ffunction-sections"
   bug. The problem happened with only .o files. If object file contains
   several .text sections then line number information showed incorrectly.
   The reason for this is that DwarfLineTable could not detect section which
   corresponds to specified address(because address is the local to the
   section). And as the result it could not select proper sequence in the
   line table. The fix is to pass SectionIndex with the address. So that it
   would be possible to differentiate addresses from various sections. With
   this fix llvm-objdump shows correct line numbers for disassembled code.

   Differential review: https://reviews.llvm.org/D58194

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354972 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-27 13:17:36 +00:00
Chandler Carruth
6b547686c5 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
2019-01-19 08:50:56 +00:00
David Blaikie
8a12381a93 libDebugInfo: Refactor error handling in range list parsing
Propagate the llvm::Error a little further up. This is NFC for
llvm-dwarfdump in this change, but allows ld.lld to emit more precise
error messages about which object and archive the erroneous DWARF is in.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349978 91177308-0d34-0410-b5e6-96231b3b80d8
2018-12-22 00:31:02 +00:00
David Blaikie
1e9194315c Reapply: DebugInfo: Assume an absence of ranges or high_pc on a CU means the CU is empty (devoid of code addresses)
Originally committed in r349333, reverted in r349353.

GCC emitted these unconditionally on/before 4.4/March 2012
Clang emitted these unconditionally on/before 3.5/March 2014

This improves performance when parsing CUs (especially those using split
DWARF) that contain no code ranges (such as the mini CUs that may be
created by ThinLTO importing - though generally they should be/are
avoided, especially for Split DWARF because it produces a lot of very
small CUs, which don't scale well in a bunch of other ways too
(including size)).

The revert was due to a (Google internal) test that had some checked in old
object files missing DW_AT_ranges. That's since been fixed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349968 91177308-0d34-0410-b5e6-96231b3b80d8
2018-12-21 22:25:01 +00:00
Eric Liu
cc188a7f8b Revert "DebugInfo: Assume an absence of ranges or high_pc on a CU means the CU is empty (devoid of code addresses)"
This reverts commit r349333. It caused internal test to fail. I have
sent more information to the author.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349353 91177308-0d34-0410-b5e6-96231b3b80d8
2018-12-17 14:14:40 +00:00
David Blaikie
c89c03b58b DebugInfo: Assume an absence of ranges or high_pc on a CU means the CU is empty (devoid of code addresses)
GCC emitted these unconditionally on/before 4.4/March 2012
Clang emitted these unconditionally on/before 3.5/March 2014

This improves performance when parsing CUs (especially those using split
DWARF) that contain no code ranges (such as the mini CUs that may be
created by ThinLTO importing - though generally they should be/are
avoided, especially for Split DWARF because it produces a lot of very
small CUs, which don't scale well in a bunch of other ways too
(including size)).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349333 91177308-0d34-0410-b5e6-96231b3b80d8
2018-12-17 08:27:19 +00:00
David Blaikie
3a054fa1b7 llvm-symbolizer: Avoid calling getFromOffset when the index entry is already available
Especially for symbolizer it can be efficient to have to search through
the entire index when it isn't needed - llvm-symbolizer looks up only a
few CUs & already has an index available in getUnitForEntry, once it's
passed down to DWARFUnitHeader::extract then there's no need for it to
call getFromOffset.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@347134 91177308-0d34-0410-b5e6-96231b3b80d8
2018-11-17 05:57:58 +00:00
Wolfgang Pieb
29d4d64637 [DWARF][NFC] Refactor a function to return Optional<> instead of bool
Minor refactor of DWARFUnit::getStringOffsetSectionItem().

Differential Revision: https://reviews.llvm.org/D53948


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345776 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-31 21:05:51 +00:00
Wolfgang Pieb
daecf945cc [DWARF] Revert r345546: Refactor range list extraction and dumping
This patch caused some internal tests to break which are being investigated.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345687 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-31 01:12:58 +00:00
Wolfgang Pieb
3efd3a74af [DWARF][NFC] Refactor range list extraction and dumping
The purpose of this patch is twofold: 
- Fold pre-DWARF v5 functionality into v5 to eliminate the need for 2 different 
  versions of range list handling. We get rid of DWARFDebugRangelist{.cpp,.h}.
- Templatize the handling of range list tables so that location list handling
  can take advantage of it as well. Location list and range list tables have the 
  same basic layout.

A non-NFC version of this patch was previously submitted with r342218, but it caused
errors with some TSan tests. This patch has no functional changes. The difference to
the non-NFC patch is that there are no changes to rangelist dumping in this patch.

Differential Revision: https://reviews.llvm.org/D53545



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345546 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-29 22:16:47 +00:00
Wolfgang Pieb
d0ae3cb27e [DWARF][NFC] cleanup (mostly leftovers from the implementation of string offsets tables)
Majority of the patch by David Blaikie.

Differential Revision: https://reviews.llvm.org/D53741


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345404 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-26 17:14:46 +00:00
David Blaikie
b8fd9d55db llvm-dwarfdump: Account for skeleton addr_base when dumping addresses in split unit in the same file
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345215 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-24 22:44:54 +00:00
David Blaikie
3a1bc560ac llvm-dwarfdump: Support RLE_addressx and RLE_startx_length in .debug_rnglists
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344835 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-20 06:16:25 +00:00
David Blaikie
b5d5e5ebf6 DebugInfo: Use debug_addr for non-dwo addresses in DWARF 5
Putting addresses in the address pool, even with non-fission, can reduce
relocations - reusing the addresses from debug_info and debug_rnglists
(the latter coming soon)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344834 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-20 06:02:15 +00:00
Wolfgang Pieb
3b86c68554 [DWARF] Make llvm-dwarfdump display location lists in a .dwp file correctly. Fixes PR38990.
Considers the index when extracting location lists from a .dwp file.
Majority of the patch by David Blaikie.

Reviewers: dblaikie

Differential revision: https://reviews.llvm.org/D53155


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344807 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-19 19:23:16 +00:00
Jonas Devlieghere
722833d6cb [dwarfdump] Verify compatibility of attribute TAGs.
Verify that DW_AT_specification and DW_AT_abstract_origin reference a
DIE with a compatible tag.

Differential revision: https://reviews.llvm.org/D38719

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342712 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-21 07:49:29 +00:00
Alexander Kornienko
d2dad5476b Revert "[DWARF] reposting r342048, which was reverted in r342056 due to buildbot errors. Adjusted 2 test cases for ARM and darwin and fixed a bug with the original change in dsymutil."
This reverts commit r342218. Due to a number of failures under TSAN. An isolated
test case is being worked on.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342399 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-17 15:40:01 +00:00
Wolfgang Pieb
dbed722b63 [DWARF] reposting r342048, which was reverted in r342056 due to buildbot
errors.
Adjusted 2 test cases for ARM and darwin and fixed a bug with the original
change in dsymutil.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342218 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-14 09:14:10 +00:00
Wolfgang Pieb
103f07fe70 Reverting r342048, which caused UBSan failures in dsymutil.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342056 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-12 14:40:04 +00:00
Wolfgang Pieb
76d3c908f5 [DWARF] Refactoring range list dumping to fold DWARF v4 functionality into v5 handling
Eliminating some duplication of rangelist dumping code at the expense of
some version-dependent code in dump and extract routines.

Reviewer: dblaikie, JDevlieghere, vleschuk

Differential revision: https://reviews.llvm.org/D51081


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342048 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-12 12:01:19 +00:00
David Blaikie
2da88b084c llvm-symbolizer: Fix bug related to TUs interfering with symbolizing
With the merge of TUs and CUs into a single container, some code that
relied on the CU range having an ordered range of contiguous addresses
(for locating a CU at a given offset) broke. But the units from
debug_info (currently only CUs, but CUs and TUs in DWARFv5) are in a
contiguous sub-range of that container - searching only through that
subrange is still valid & so do that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341889 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-11 02:04:45 +00:00
Victor Leschuk
f030fcc4ba [DWARF] Refactor DWARF classes to use unified error reporting. NFC.
DWARF-related classes in lib/DebugInfo/DWARF contained 
duplicating code for creating StringError instances, like:

template <typename... Ts>
static Error createError(char const *Fmt, const Ts &... Vals) {
  std::string Buffer;
  raw_string_ostream Stream(Buffer);
  Stream << format(Fmt, Vals...);
  return make_error<StringError>(Stream.str(), inconvertibleErrorCode());
}

Similar function was placed in Support lib in https://reviews.llvm.org/D49824

This revision makes DWARF classes use this function
instead of their local implementation of it.

Reviewers: aprantl, dblaikie, probinson, wolfgangp, JDevlieghere, jhenderson

Reviewed By: JDevlieghere, jhenderson

Differential Revision: https://reviews.llvm.org/D49964



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@340163 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-20 09:59:08 +00:00
Paul Robinson
a42866d162 [DebugInfo/DWARF] [4/4] Unify handling of compile and type units. NFC
This is patch 4 of 4 NFC refactorings to handle type units and compile
units more consistently and with less concern about the object-file
section that they came from.

Patch 4 combines separate DWARFUnitVectors for compile and type units
into a single DWARFUnitVector that contains both.  For now the
implementation distinguishes compile units from type units by putting
all compile units at the front of the vector, reflecting the DWARF v4
distinction between .debug_info and .debug_types sections.  A future
patch will change this to allow the free mixing of unit kinds, as is
specified by DWARF v5.

Differential Revision: https://reviews.llvm.org/D49744

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338633 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-01 20:54:11 +00:00
Paul Robinson
72eb9b0a58 [DebugInfo/DWARF] [3/4] Rename DWARFUnitSection to DWARFUnitVector. NFC
This is patch 3 of 4 NFC refactorings to handle type units and compile
units more consistently and with less concern about the object-file
section that they came from.

Patch 3 simply renames DWARFUnitSection to DWARFUnitVector, as the
object-file section of a unit is nearly irrelevant now.

Differential Revision: https://reviews.llvm.org/D49743

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338632 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-01 20:49:44 +00:00
Paul Robinson
2b9857ed4f [DebugInfo/DWARF] [2/4] Type units no longer in a std::deque. NFC
This is patch 2 of 4 NFC refactorings to handle type units and compile
units more consistently and with less concern about the object-file
section that they came from.

Patch 2 takes the existing std::deque<DWARFUnitSection> for type units
and makes it a simple DWARFUnitSection, simplifying the handling of
type units and making it more consistent with compile units.

Differential Revision: https://reviews.llvm.org/D49742

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338629 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-01 20:46:46 +00:00
Paul Robinson
55a0ed21cd [DebugInfo/DWARF] [1/4] De-templatize DWARFUnitSection. NFC
This is patch 1 of 4 NFC refactorings to handle type units and compile
units more consistently and with less concern about the object-file
section that they came from.

Patch 1 replaces the templated DWARFUnitSection with a non-templated
version. That is, instead of being a SmallVector of pointers to a
specific unit kind, it is not a SmallVector of pointers to the base
class for both type and compile units.  Virtual methods are magic.

Differential Revision: https://reviews.llvm.org/D49741

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338628 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-01 20:43:47 +00:00
Wolfgang Pieb
7bfb55f7a4 [DWARF v5] Don't report an error when the .debug_rnglists section is empty or non-existent. Fixes PR38297.
Reviewer: JDevlieghere

Differential Revision: https://reviews.llvm.org/D49815
 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337993 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-26 01:12:41 +00:00
Wolfgang Pieb
3e597f45e6 [DWARF v5] Refactor range lists dumping by using a more generic way of handling tables of lists.
The intent is to use it for location list tables as well. Change is almost NFC with the exception
of the spelling of some strings used during dumping (all lowercase now).

Reviewer: JDevlieghere

Differential Revision: https://reviews.llvm.org/D49500



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337763 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-23 22:37:17 +00:00
Fangrui Song
adfcff45ee [DebugInfo] Fix getPreviousSibling after r336823
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336837 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-11 19:09:37 +00:00
Jonas Devlieghere
f8497881d6 [DebugInfo] Make children iterator bidirectional
Make the DIE iterator bidirectional so we can move to the previous
sibling of a DIE.

Differential revision: https://reviews.llvm.org/D49173

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336823 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-11 17:11:11 +00:00
Wolfgang Pieb
5a4174c540 [DWARF] Improved error reporting for range lists.
Errors found processing the DW_AT_ranges attribute are propagated by lower level 
routines and reported by their callers.

Reviewer: JDevlieghere

Differential Revision: https://reviews.llvm.org/D48344



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335188 91177308-0d34-0410-b5e6-96231b3b80d8
2018-06-20 22:56:37 +00:00
Paul Robinson
04a387aa0f [DWARFv5] Put the DWO ID in its place.
In DWARF v5, the DWO ID is in the (split/skeleton) CU header, not an
attribute on the CU DIE.

This changes the size of those headers, so use the parsed size whenever
we have one, for simplicitly.

Differential Revision: https://reviews.llvm.org/D47158

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333004 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-22 17:27:31 +00:00
Jonas Devlieghere
74157fc710 [DebugInfo] Use absolute addresses in location lists
Rather than relying on the user to do the address calculating in
DW_AT_location we should just dump the absolute address.

rdar://problem/38513870

Differential revision: https://reviews.llvm.org/D47152

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332873 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-21 19:36:54 +00:00
Wolfgang Pieb
02babe8338 Addressing a couple of compiler warnings introduced with r332759.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332766 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-18 20:51:16 +00:00
Wolfgang Pieb
a576ca1044 Fixing build error introduced with r332759.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332762 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-18 20:35:13 +00:00
Wolfgang Pieb
eab311b661 [DWARF v5] Improved support for .debug_rnglists (consumer). Enables any consumer to
extract DWARF v5 encoded rangelists.

Reviewer: JDevlieghere

Differential Revision: https://reviews.llvm.org/D45549


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332759 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-18 20:12:54 +00:00
Paul Robinson
989920616f [DWARF] Factor out a DWARFUnitHeader class. NFC
Extract information related to a "unit header" from DWARFUnit into a
new DWARFUnitHeader class, and add a DWARFUnit member for the header.
This is one step in the direction of allowing type units in the
.debug_info section for DWARF v5.

Differential Revision: https://reviews.llvm.org/D46707

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332289 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-14 20:32:31 +00:00
Wolfgang Pieb
3dc44a9d48 [DWARF] Fixing a bug in DWARF v5 string offsets tables where the length encoded the contribution
length excluding the table header. Instead it must encode the contribution length minus the length
field itself.

Reviewer: JDevliegehere

Differential Revision: https://reviews.llvm.org/D45922


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332030 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-10 20:02:34 +00:00
David Blaikie
df69f1ffbe llvm-symbolizer: Handle function definitions nested within other functions
LLVM always puts function definition DIEs at the top level, but under
some circumstances GCC does not (at least in this case with member
functions of a function-local type).

To ensure that doesn't appear as though the local type's member function
is unduly inlined within the outer function - ensure the inline
discovery DIE parent walk stops at the first DW_TAG_subprogram.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331291 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-01 18:08:45 +00:00
Jonas Devlieghere
0c191c5e26 [DebugInfo] Use WithColor to print errors/warnings
Use the convenience methods from WithColor to consistently print errors
and warnings in libDebugInfo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330092 91177308-0d34-0410-b5e6-96231b3b80d8
2018-04-14 22:07:23 +00:00
Rafael Espindola
d227a3b47e Handle abbr_offset with relocations.
This is mostly just plumbing to get a DWARFDataExtractor where we
compute abbr_offset so we can use getRelocatedValue.

This is part of PR36793.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328154 91177308-0d34-0410-b5e6-96231b3b80d8
2018-03-21 21:31:25 +00:00
Pavel Labath
fa49d7da44 DWARF: Unify form size handling code
Summary:
This patch replaces the two switches which are deducing the size of
various forms with a single implementation. I have put the new
implementation into BinaryFormat, to avoid introducing dependencies
between the two independent libraries (DebugInfo and CodeGen) that need
this functionality.

Reviewers: aprantl, JDevlieghere, dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D44418

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327486 91177308-0d34-0410-b5e6-96231b3b80d8
2018-03-14 09:39:54 +00:00
David Blaikie
232b1a899c Revert "Rewrite the cached map used for locating the most precise DIE among inlined subroutines for a given address."
Seeing some inlining missing in internal uses of symbolizer. I'll work
on a reproduction, tests, improvements & recommit as soon as possible.

(Chandler would like it to be known that this improvement did make
check-llvm 4x faster... - so there's certainly some fairly good
motivation to push on fixing/figuring this out & getting it back in)

This reverts commit r321345.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@324981 91177308-0d34-0410-b5e6-96231b3b80d8
2018-02-13 01:52:30 +00:00
Paul Robinson
a58b230718 Stop tracking .debug_line_str in DWARFUnit. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323701 91177308-0d34-0410-b5e6-96231b3b80d8
2018-01-29 22:02:56 +00:00
Paul Robinson
920b6750b9 [DWARFv5] Support DW_FORM_line_strp in llvm-dwarfdump.
This form is like DW_FORM_strp, but points to .debug_line_str instead
of .debug_str as the string section.  It's intended to be used from
the line-table header, and allows string-pooling of directory and
filenames across compilation units.

Differential Revision: https://reviews.llvm.org/D42553

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323476 91177308-0d34-0410-b5e6-96231b3b80d8
2018-01-25 22:02:36 +00:00
Chandler Carruth
45383c8c85 Rewrite the cached map used for locating the most precise DIE among
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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321345 91177308-0d34-0410-b5e6-96231b3b80d8
2017-12-22 06:41:23 +00:00