Commit Graph

87 Commits

Author SHA1 Message Date
Zequan Wu b74a01a80b Reland "[LLDB][NFC] Decouple dwarf location table from DWARFExpression."
This reland 227dffd0b6 and
562c3467a6 with failed api tests fixed by keeping
function base file addres in DWARFExpressionList.
2022-07-12 10:54:24 -07:00
Jonas Devlieghere e4c5bca597
Revert "[LLDB][NFC] Decouple dwarf location table from DWARFExpression."
This reverts commit 227dffd0b6 and its
follow up 562c3467a6 because it breaks a
bunch of tests on GreenDragon:

https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45155/
2022-07-07 16:36:10 -07:00
Zequan Wu 227dffd0b6 [LLDB][NFC] Decouple dwarf location table from DWARFExpression.
Differential Revision: https://reviews.llvm.org/D125509
2022-07-07 10:26:58 -07:00
Kazu Hirata aa88161b37 [lldb] Use value_or instead of getValueOr (NFC) 2022-06-19 09:12:01 -07:00
Shafik Yaghmour ae869d4484 [LLDB] Remove cases of using namespace llvm:: from header file
We have using namespace llvm::dwarf in dwarf.h header globally. Replacing that
with a using namespace within lldb_private::dwarf and moving to a
using namespace lldb_private::dwarf in .cpp files and fully qualified names
in the few header files.

Differential Revision: https://reviews.llvm.org/D120836
2022-03-03 10:39:06 -08:00
serge-sans-paille 290e482342 Cleanup LLVMDWARFDebugInfo
As usual with that header cleanup series, some implicit dependencies now need to
be explicit:

llvm/DebugInfo/DWARF/DWARFContext.h no longer includes:
- "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
- "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
- "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
- "llvm/DebugInfo/DWARF/DWARFDebugAranges.h"
- "llvm/DebugInfo/DWARF/DWARFDebugFrame.h"
- "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
- "llvm/DebugInfo/DWARF/DWARFDebugMacro.h"
- "llvm/DebugInfo/DWARF/DWARFGdbIndex.h"
- "llvm/DebugInfo/DWARF/DWARFSection.h"
- "llvm/DebugInfo/DWARF/DWARFTypeUnit.h"
- "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"

Plus llvm/Support/Errc.h not included by a bunch of llvm/DebugInfo/DWARF/DWARF*.h files

Preprocessed lines to build llvm on my setup:
after: 1065629059
before: 1066621848

Which is a great diff!

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D119723
2022-02-15 09:16:03 +01:00
Kazu Hirata b8336280d8 [lldb] Use nullptr instead of 0 or NULL (NFC)
This is a re-submission of 24d2405588
without the hunks in HostNativeThreadBase.{h,cpp}, which break builds
on Windows.

Identified with modernize-use-nullptr.
2022-01-01 11:54:25 -08:00
Kazu Hirata 95f7112be8 Revert "[lldb] Use nullptr instead of 0 or NULL (NFC)"
This reverts commit 913457acf0.

It again broke builds on Windows:

  lldb/source/Host/common/HostNativeThreadBase.cpp(37,14): error:
  assigning to 'lldb::thread_result_t' (aka 'unsigned int') from
  incompatible type 'std::nullptr_t'
2022-01-01 11:15:14 -08:00
Kazu Hirata 913457acf0 [lldb] Use nullptr instead of 0 or NULL (NFC)
This is a re-submission of 24d2405588
without the hunk in HostNativeThreadBase.h, which breaks builds on
Windows.

Identified with modernize-use-nullptr.
2022-01-01 10:48:56 -08:00
Nico Weber 4f2eeb6a65 Revert "[lldb] Use nullptr instead of 0 or NULL (NFC)"
This reverts commit 24d2405588.
Breaks building on Windows:

    ../../lldb/include\lldb/Host/HostNativeThreadBase.h(49,36): error:
        cannot initialize a member subobject of type 'lldb::thread_result_t'
        (aka 'unsigned int') with an rvalue of type 'std::nullptr_t'
      lldb::thread_result_t m_result = nullptr;
                                       ^~~~~~~
    1 error generated.
2022-01-01 13:35:54 -05:00
Kazu Hirata 24d2405588 [lldb] Use nullptr instead of 0 or NULL (NFC)
Identified with modernize-use-nullptr.
2022-01-01 08:54:05 -08:00
Kazu Hirata 9c0a4227a9 Use Optional::getValueOr (NFC) 2021-12-24 20:57:40 -08:00
Adrian Prantl 4651576edd Recognize the Swift compiler in DW_AT_producer
This patch adds support for Swift compiler producer strings to DWARFUnit.

Differential Revision: https://reviews.llvm.org/D111278
2021-10-07 13:54:28 -07:00
Adrian Prantl 14aa3f3703 Use llvm::VersionTuple to store DWARF producer info (NFC)
This has the nice side-effect that it can actually store the quadruple version numbers that Apple's tools are using nowadays.

rdar://82982162

Differential Revision: https://reviews.llvm.org/D111200
2021-10-06 14:56:16 -07:00
Kim-Anh Tran ec671f3ea0 [lldb] Support .debug_rnglists.dwo sections in dwp file
This patch considers the CU index entry
when reading the .debug_rnglists.dwo section.

Reviewed By: jankratochvil

Differential Revision: https://reviews.llvm.org/D107456
2021-09-03 15:19:50 +02:00
Eric Leese fb09f365ae [lldb] [DWARF-5] Be lazier about loading .dwo files
This change makes sure that DwarfUnit does not load a .dwo file until
necessary. I also take advantage of DWARF 5's guarantee that the first
support file is also the primary file to make it possible to create
a compile unit without loading the .dwo file.

Testcases now require Linux as it is needed for -gsplit-dwarf.

Review By: jankratochvil, dblaikie

Differential Revision: https://reviews.llvm.org/D100299
2021-07-31 10:45:31 +02:00
Stella Stamenova dfb6f7b015 Revert "[lldb] [DWARF-5] Be lazier about loading .dwo files"
This reverts commit 8dfd6cae9b.

This change broke the windows lldb bot:
https://lab.llvm.org/buildbot/#/builders/83/builds/8842
2021-07-30 18:33:13 -07:00
Eric Leese 8dfd6cae9b [lldb] [DWARF-5] Be lazier about loading .dwo files
This change makes sure that DwarfUnit does not load a .dwo file until
necessary. I also take advantage of DWARF 5's guarantee that the first
support file is also the primary file to make it possible to create
a compile unit without loading the .dwo file.

Review By: jankratochvil, dblaikie

Differential Revision: https://reviews.llvm.org/D100299
2021-07-30 23:17:06 +02:00
Jan Kratochvil d0e6d946b6 Revert "[lldb] [DWARF-5] Be lazier about loading .dwo files"
This reverts commit e7b8ba103a.

It broke 32-bit ARM - lldb-arm-ubuntu, reported by omjavaid:
  https://lab.llvm.org/buildbot/#/builders/17/builds/9595
2021-07-30 14:54:27 +02:00
Eric Leese e7b8ba103a [lldb] [DWARF-5] Be lazier about loading .dwo files
This change makes sure that DwarfUnit does not load a .dwo file until
necessary. I also take advantage of DWARF 5's guarantee that the first
support file is also the primary file to make it possible to create
a compile unit without loading the .dwo file.

Review By: jankratochvil, dblaikie

Differential Revision: https://reviews.llvm.org/D100299
2021-07-30 13:34:51 +02:00
Jan Kratochvil 278df28557 [nfc] [lldb] Rename GetRnglist() to GetRnglistTable()
My D99653 implemented a getter GetRnglist() for m_rnglist_table.

That was confusing as the getter returns DWARFDebugRnglistTable which
contains DWARFDebugRnglist as its elements.
2021-07-21 10:45:37 +02:00
Jan Kratochvil 6d19c84cd9 [lldb] Improve invalid DWARF DW_AT_ranges error reporting
In D98289#inline-939112 @dblaikie said:
  Perhaps this could be more informative about what makes the range list
  index of 0 invalid? "index 0 out of range of range list table (with
  range list base 0xXXX) with offset entry count of XX (valid indexes
  0-(XX-1))" Maybe that's too verbose/not worth worrying about since
  this'll only be relevant to DWARF producers trying to debug their
  DWARFv5, maybe no one will ever see this message in practice. Just
  a thought.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D102851
2021-05-20 21:37:01 +02:00
Jan Kratochvil d131081719 [lldb] 2/2: Fix DW_AT_ranges DW_FORM_sec_offset not using DW_AT_rnglists_base (used by GCC)
DW_AT_ranges can use DW_FORM_sec_offset (instead of DW_FORM_rnglistx).
In such case DW_AT_rnglists_base does not need to be present.
DWARF-5 spec:
        "If the offset_entry_count is zero, then DW_FORM_rnglistx cannot
        be used to access a range list; DW_FORM_sec_offset must be used
        instead. If the offset_entry_count is non-zero, then
        DW_FORM_rnglistx may be used to access a range list;"

This fix is for TestTypeCompletion.py category `dwarf` using GCC with DWARF-5.

The fix just provides GetRnglist() lazy getter for `m_rnglist_table`.
The testcase is easier to review by:
        diff -u lldb/test/Shell/SymbolFile/DWARF/DW_AT_low_pc-addrx.s \
          lldb/test/Shell/SymbolFile/DWARF/DW_AT_range-DW_FORM_sec_offset.s

Differential Revision: https://reviews.llvm.org/D98289
2021-05-19 15:57:40 +02:00
Jan Kratochvil 9dd861a4f5 [nfc] [lldb] 1/2: Fix DW_AT_ranges DW_FORM_sec_offset not using DW_AT_rnglists_base (used by GCC)
Refactor code only for D98289.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D99653
2021-05-19 15:57:40 +02:00
Jorge Gorbe Moya 979ca1c05f Defer the decision whether to use the CU or TU index until after reading the unit header.
In DWARF v4 compile units go in .debug_info and type units go in
.debug_types. However, in v5 both kinds of units are in .debug_info.
Therefore we can't decide whether to use the CU or TU index just by
looking at which section we're reading from. We have to wait until we
have read the unit type from the header.

Differential Revision: https://reviews.llvm.org/D96194
2021-02-23 13:26:11 -08:00
Jorge Gorbe Moya a39b19821b Make DWARFUnit use the dwo_id from the DWARF5 CU header.
In split DWARF v5 files, the DWO id is no longer in the DW_AT_GNU_dwo_id
attribute. It's in the CU header instead. This change makes lldb look in
both places.

Differential Revision: https://reviews.llvm.org/D93444
2021-01-05 16:40:37 -08:00
Jan Kratochvil 7bf066a20f [nfc] [lldb] Fix harmless slicing of DWARFDIE
Differential Revision: https://reviews.llvm.org/D89875
2020-10-21 15:49:53 +02:00
Jan Kratochvil 0e5248be86 [nfc] [lldb] Move LookupAddress to DWARFCompileUnit
LookupAddress makes no sense for DWARFTypeUnit.
Also make GetNonSkeletonUnit to preserve the called type.

Differential Revision: https://reviews.llvm.org/D89646
2020-10-19 12:44:33 +02:00
David Blaikie f7a49d2aa6 [WIP][DebugInfo] Lazily parse debug_loclist offsets
Parsing DWARFv5 debug_loclist offsets when a CU is parsed is weighing
down memory usage of symbolizers that don't need to parse this data at
all. There's not much benefit to caching these anyway - since they are
O(1) lookup and reading once you know where the offset list starts (and
can do bounds checking with the offset list size too).

In general, I think it might be time to start paying down some of the
technical debt of loc/loclist/range/rnglist parsing to try to unify it a
bit more.

eg:

* Currently DWARFUnit has: RangeSection, RangeSectionBase, LocSection,
  LocSectionBase, LocTable, RngListTable, LoclistTableHeader (be nice if
  these were all wrapped up in two variables - one for loclists, one for
  rnglists)

* rnglists and loclists are handled differently (see:
  LoclistTableHeader, but no RnglistTableHeader)

* maybe all these types could be less stateful - lazily parse what they
  need to, even reparsing rather than caching because it doesn't seem
  too expensive, for instance. (though admittedly so long as it's
  constantcost/overead per compilatiton that's probably adequate)

* Maybe implementing and using a DWARFDataExtractor that can be
  sub-ranged (so we could slice it up to just the single contribution) -
  though maybe that's not so useful because loc/ranges need to refer to
  it by absolute, not contribution-relative mechanisms

Differential Revision: https://reviews.llvm.org/D86110
2020-08-18 10:49:39 -07:00
Konrad Kleine eaebcbc679 [lldb] NFC remove DISALLOW_COPY_AND_ASSIGN
Summary:
This is how I applied my clang-tidy check (see
https://reviews.llvm.org/D80531) in order to remove
`DISALLOW_COPY_AND_ASSIGN` and have deleted copy ctors and deleted
assignment operators instead.

```
lang=bash
grep DISALLOW_COPY_AND_ASSIGN /opt/notnfs/kkleine/llvm/lldb -r -l | sort | uniq > files

for i in $(cat files);
do
  clang-tidy \
    --checks="-*,modernize-replace-disallow-copy-and-assign-macro" \
    --format-style=LLVM \
    --header-filter=.* \
    --fix \
    -fix-errors \
    $i;
done
```

Reviewers: espindola, labath, aprantl, teemperor

Reviewed By: labath, aprantl, teemperor

Subscribers: teemperor, aprantl, labath, emaste, sbc100, aheejin, MaskRay, arphaman, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D80543
2020-06-02 13:23:53 -04:00
Adrian Prantl 1e05d7b3d3 Remap the target (Xcode) SDK directory to the host SDK directory.
This is mostly useful for Swift support; it allows LLDB to substitute
a matching SDK it shipped with instead of the sysroot path that was
used at compile time.

The goal of this is to make the Xcode SDK something that behaves more
like the compiler's resource directory, as in that it ships with LLDB
rather than with the debugged program. This important primarily for
importing Swift and Clang modules in the expression evaluator, and
getting at the APINotes from the SDK in Swift.

For a cross-debugging scenario, this means you have to have an SDK for
your target installed alongside LLDB. In Xcode this will always be the
case.

rdar://problem/60640017

Differential Revision: https://reviews.llvm.org/D76471
2020-04-06 15:51:30 -07:00
Pavel Labath 8131cb6e18 [lldb/DWARF] Add support for location lists in package files
The only thing needed was to account for the offset from the
debug_cu_index section when searching for the location list.

This patch also fixes a bug in the Module::ParseAllDebugSymbols
function, which meant that we would only parse the variables of the
first compile unit in the module. This function is only used from
lldb-test, so this does not fix any real issue, besides preventing me
from writing a test for this patch.
2020-02-19 14:33:58 +01:00
Pavel Labath 00539d8b64 [lldb/DWARF] Support the debug_str_offsets section in dwp files
Summary:
In dwp files a constant (from the debug_cu_index section) needs to be
added to each reference into the debug_str_offsets section.

I've tried to implement this to roughly match the llvm flow: I've
changed the DWARFormValue to stop resolving the indirect string
references directly -- instead, it calls into DWARFUnit, which resolves
this for it (similar to how it already resolves indirect range and
location list references). I've also done a small refactor of the string
offset base computation code in DWARFUnit in order to make it easier to
access the debug_cu_index base offset.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D74723
2020-02-18 11:02:34 +01:00
Jonas Devlieghere cdc514e4c6 [lldb] Update header guards to be consistent and compliant with LLVM (NFC)
LLDB has a few different styles of header guards and they're not very
consistent because things get moved around or copy/pasted. This patch
unifies the header guards across LLDB and converts everything to match
LLVM's style.

Differential revision: https://reviews.llvm.org/D74743
2020-02-17 23:15:40 -08:00
Pavel Labath 67f63f3f7c [lldb/DWARF] Re-enable basic dwp support
Summary:
This patch removes the bitrotted SymbolFileDWARF(Dwo)Dwp classes, and
replaces them with dwp support implemented directly inside
SymbolFileDWARFDwo, in a manner mirroring the implementation in llvm.
This patch does:
- add support for the .debug_cu_index section to our DWARFContext
- adds a llvm::DWARFUnitIndex argument to the DWARFUnit constructors.
  This argument is used to look up the offsets of the debug_info and
  debug_abbrev contributions in the sections of the dwp file.
- makes sure the creation of the DebugInfo object as well as the initial
  discovery of DWARFUnits is thread-safe, as we can now call this
  concurrently when doing parallel indexing.

This patch does not:
- use the DWARFUnitIndex to search for other kinds of contributions
  (debug_loc, debug_ranges, etc.). This means that units which reference
  these sections will not work correctly. These will be handled by
  follow-up patches, but even the present level of support is sufficient
  to enable basic functionality.
- Make the llvm::DWARFContext thread-safe. Right now, it just avoids this
  problem by ensuring everything is initialized ahead of time. However,
  this is something we will run into more often as we try to use more of
  llvm, and so I plan to start looking into our options here.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: mgorny, mgrang, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73783
2020-02-17 14:10:36 +01:00
Pavel Labath 9dc84e9b02 [lldb/DWARF] Don't hold a unique SymbolFileDWARFDwo in a DWARFUnit
This is the second dwp preparatory patch. When a SymbolFileDWARFDwo will
hold more than one split unit, it will not be able to be uniquely owned
by a single DWARFUnit. I achieve this by changing the
unique_ptr<SymbolFileDWARFDwo> member of DWARFUnit to
shared_ptr<DWARFUnit>. The shared_ptr points to a DWARFUnit, but it is
in fact holding the entire SymbolFileDWARFDwo alive. This is the same
method used by llvm DWARFUnit (except that is uses the DWARFContext
class).

Differential Revision: https://reviews.llvm.org/D73782
2020-02-14 11:09:45 +01:00
Pavel Labath e3aa062ae9 [lldb/DWARF] Don't assume that a SymbolFileDWARFDwo contains one compile unit
Summary:
This is a preparatory patch to re-enable DWP support in lldb (we already
have code claiming to do that, but it has been completely broken for a
while now).

The idea of the new approach is to make the SymbolFileDWARFDwo class
handle both dwo and dwo files, similar to how llvm uses one DWARFContext
to handle the two.

The first step is to remove the assumption that a SymbolFileDWARFDwo
holds just a single compile unit, i.e. the GetBaseCompileUnit method.
This requires changing the way how we reach the skeleton compile unit
(and the lldb_private::CompileUnit) from a dwo unit, which was
previously done via GetSymbolFile()->GetBaseCompileUnit() (and some
virtual dispatch).

The new approach reuses the "user data" mechanism of DWARFUnits, which
was used to link dwarf units (both skeleton and split) to their
lldb_private counterparts. Now, this is done only for non-dwo units, and
instead of that, the dwo units holds a pointer to the relevant skeleton
unit.

Reviewers: JDevlieghere, aprantl, clayborg

Reviewed By: JDevlieghere, clayborg

Subscribers: arphaman, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73781
2020-02-05 20:37:56 -08:00
Jan Kratochvil 789beeeca3 [lldb] Move non-DWARF code: DWARFUnit -> SymbolFileDWARF
This patchset is removing non-DWARF code from DWARFUnit for better
future merge with LLVM DWARF as discussed with @labath.

Differential revision: https://reviews.llvm.org/D70646
2020-01-31 15:16:31 +01:00
Pavel Labath e65282deca [lldb/DWARF] Don't automatically search dwo unit attributes
This patch removes the code (deep inside DWARFDebugInfoEntry) which
automagically returned the attributes of the dwo unit DIE when asking
for the attributes of the skeleton unit.  This is fairly hacky, and not
consistent with how llvm DWARF parser operates.

Instead, I change the code the explicitly request (via
GetNonSkeletonUnit) the right unit to search (there were just two places
that needed this). If it turns out we need this more often, we can
create a utility function (external to DWARFUnit) for doing this.
2020-01-10 13:29:24 +01:00
Pavel Labath cd5da94d80 [lldb/DWARF] Fix mixed v4+v5 location lists
Summary:
Our code was expecting that a single (symbol) file contains only one
kind of location lists. This is not correct (on non-apple platforms, at
least) as a file can compile units with different dwarf versions.

This patch moves the deteremination of location list flavour down to the
compile unit level, fixing this problem. I have also tried to rougly
align the code with the llvm DWARFUnit. Fully matching the API is not
possible because of how lldb's DWARFExpression lives separately from the
rest of the DWARF code, but this is at least a step in the right
direction.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: dblaikie, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71751
2020-01-09 13:19:29 +01:00
Pavel Labath 9bb01efa49 [lldb/DWARF] Add is_dwo member to DWARFUnit
Summary:
A skeleton unit can easily be detected by checking the m_dwo_symbol_file
member, but we cannot tell a split unit from a normal unit from the
"inside", which is sometimes useful.

This patch adds a m_is_dwo member to enable this, and align the code
with llvm::DWARFUnit. Right now it's only used to avoid creating a split
unit inside another split unit (which removes one override from
SymbolFileDWARFDwo and brings us a step closer to deleting it), but my
main motivation is fixing the handling of location lists in mixed v4&v5
files. This comes in a separate patch.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: dblaikie, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71750
2020-01-09 13:19:29 +01:00
Pavel Labath e40ac74dac [lldb] Remove DWARFUnit::AppendDIEsWithTag
This function is not very useful, as it's forcing a materialization of
the returned DIEs, and calling it is not substantially simpler than just
iterating over the DIEs manually. Delete it, and rewrite the single
caller.
2019-12-23 15:50:30 +01:00
Pavel Labath c8b74ee264 [lldb/DWARF] Add support for DW_AT_loclists_base&DW_FORM_loclistx
Summary:
This adds support for DWARF5 location lists which are specified
indirectly, via an index into the debug_loclists offset table. This
includes parsing the DW_AT_loclists_base attribute which determines the
location of this offset table, and support for new form DW_FORM_loclistx
which is used in conjuction with DW_AT_location to refer to the location
lists in this way.

The code uses the llvm class to parse the offset information, and I've
also tried to structure it similarly to how the relevant llvm
functionality works.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71268
2019-12-11 11:06:17 +01:00
Pavel Labath f5767e284b [lldb/DWARF] Switch to llvm debug_rnglists parser
Summary:
Our rnglist support was working only for the trivial cases (one CU),
because we only ever parsed one contribution out of the debug_rnglists
section. This means we were never able to resolve range lists for the
second and subsequent units (DW_FORM_sec_offset references came out
blang, and DW_FORM_rnglistx references always used the ranges lists from
the first unit).

Since both llvm and lldb rnglist parsers are sufficiently
self-contained, and operate similarly, we can fix this problem by
switching to the llvm parser instead. Besides the changes which are due
to variations in the interface, the main thing is that now the range
list object is a member of the DWARFUnit, instead of the entire symbol
file. This ensures that each unit can get it's own private set of range
list indices, and is consistent with how llvm's DWARFUnit does it
(overall, I've tried to structure the code the same way as the llvm
version).

I've also added a test case for the two unit scenario.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: dblaikie, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71021
2019-12-05 13:02:03 +01:00
Alex Langford 0e252e38ef [Symbol] Use llvm::Expected when getting TypeSystems
Summary:
This commit achieves the following:
- Functions used to return a `TypeSystem *` return an
  `llvm::Expected<TypeSystem *>` now. This means that the result of a call
  is always checked, forcing clients to move more carefully.
- `TypeSystemMap::GetTypeSystemForLanguage` will either return an Error or a
  non-null pointer to a TypeSystem.

Reviewers: JDevlieghere, davide, compnerd

Subscribers: jdoerfert, lldb-commits

Differential Revision: https://reviews.llvm.org/D65122

llvm-svn: 367360
2019-07-30 22:12:34 +00:00
Pavel Labath 3b9269882e DWARF: Add "dwo_num" field to the DIERef class
Summary:
When dwo support was introduced, it used a trick where debug info
entries were referenced by the offset of the compile unit in the main
file, but the die offset was relative to the dwo file. Although there
was some elegance to it, this representation was starting to reach its
breaking point:
- the fact that the skeleton compile unit owned the DWO file meant that
  it was impossible (or at least hard and unintuitive) to support DWO
  files containing more than one compile unit. These kinds of files are
  produced by LTO for example.
- it made it impossible to reference any DIEs in the skeleton compile
  unit (although the skeleton units are generally empty, clang still
  puts some info into them with -fsplit-dwarf-inlining).
- (current motivation) it made it very hard to support type units placed
  in DWO files, as type units don't have any skeleton units which could
  be referenced in the main file

This patch addresses this problem by introducing an new
"dwo_num" field to the DIERef class, whose purpose is to identify the
dwo file. It's kind of similar to the dwo_id field in DWARF5 unit
headers, but while this is a 64bit hash whose main purpose is to catch
file mismatches, this is just a smaller integer used to indentify a
loaded dwo file. Currently, this is based on the index of the skeleton
compile unit which owns the dwo file, but it is intended to be
eventually independent of that (to support the LTO use case).

Simultaneously the cu_offset is dropped to conserve space, as it is no
longer necessary.  This means we can remove the "BaseObjectOffset" field
from the DWARFUnit class. It also means we can remove some of the
workarounds put in place to support the skeleton-unit+dwo-die combo.
More work is needed to remove all of them, which is out of scope of this
patch.

Reviewers: JDevlieghere, clayborg, aprantl

Subscribers: mehdi_amini, dexonsmith, arphaman, lldb-commits

Differential Revision: https://reviews.llvm.org/D63428

llvm-svn: 364009
2019-06-21 07:56:50 +00:00
Pavel Labath 6a2eb36710 Have DWARFUnit store a *reference* to SymbolFileDWARF
Previously it was storing a *pointer*, which left open the possibility
of this pointer being null. We never made use of that possibility (it
does not make sense), and most of the code was already assuming that.
However, there were a couple of null-checks scattered around the code.

This patch replaces the reference with a pointer, making the
non-null-ness explicit, and removes the remaining null-checks.

llvm-svn: 363381
2019-06-14 13:01:16 +00:00
Pavel Labath ca9c3de17e DWARF: Share line tables of type units
Summary:
This patch creates a cache of file lists in line tables referenced by
type units.  This cache is used to avoid parsing a line table twice
(since a file list will generally be shared by many type units).

It also sets things up in a way that parsing of DW_AT_decl_file
attributes will keep working even when we stop creating lldb compile
units for dwarf type units, but it stops short of actually doing that.
This means that the request for files now go directly to SymbolFileDWARF
instead of being routed there indirectly via the
lldb_private::CompileUnit class.

As a result of this, a number of occurences of SymbolContext variables
in DWARFASTParserClang have become unused, so I remove them.

This patch reduces the number of times a file list is being parsed, but
the situation is still suboptimal, as the parsed list is being copied
multiple times. This will be fixed when we stop creating CompileUnits
for DWARF type units.

Reviewers: clayborg, aprantl, JDevlieghere

Subscribers: jdoerfert, lldb-commits

Differential Revision: https://reviews.llvm.org/D62894

llvm-svn: 363143
2019-06-12 11:29:50 +00:00
Pavel Labath 78cfe1e6fe DWARF: Fix address range support in mixed 4+5 scenario
Summary:
debug_ranges got renamed to debug_rnglists in DWARF 5. Prior to this
patch lldb was just picking the first section it could find in the file,
and using that for all address ranges lookups. This is not correct in
case the file contains a mixture of compile units with various standard
versions (not a completely unlikely scenario).

In this patch I make lldb support reading from both sections
simulaneously, and decide the correct section to use based on the
version number of the compile unit. SymbolFileDWARF::DebugRanges is
split into GetDebugRanges and GetDebugRngLists (the first one is renamed
mainly so we can catch all incorrect usages).

I tried to structure the code similarly to how llvm handles this logic
(hence DWARFUnit::FindRnglistFromOffset/Index), but the implementations
are still relatively far from each other.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D62302

llvm-svn: 361938
2019-05-29 09:22:36 +00:00
Greg Clayton 6aad81cd96 Cleanup fixed form sizes.
The fix form sizes use to have two arrays: one for 4 byte addresses and in for 8 byte addresses. The table had an issue where DW_FORM_flag_present wasn't being represented as a fixed size form because its actual size _is_ zero and zero was used to indicate the form isn't fixed in size. Any code that needed to quickly access the DWARF had to get a FixedFormSizes instance using the address byte size.

This fix cleans things up by adding a DWARFFormValue::GetFixedSize() both as a static method and as a member function on DWARFFormValue. It correctly can indicate if a form size is zero. This cleanup is a precursor to a follow up patch where I hope to speed up DWARF parsing.

I verified performance doesn't regress by loading hundreds of DWARF files and setting a breakpoint by file and line and by name in files that do not have DWARF indexes. Performance remained consistent between the two approaches.


Differential Revision: https://reviews.llvm.org/D62416

llvm-svn: 361675
2019-05-24 22:08:50 +00:00