Commit Graph

11 Commits

Author SHA1 Message Date
Pavel Labath 1211baa51c Breakpad: Generate unwind plans from STACK CFI records
Summary:
This patch implements the GetUnwindPlan interface (added in the previous
patch) for SymbolFileBreakpad, and uses it to generate unwind plans from
STACK CFI records in breakpad files.

We first perform a light-weight parse of the breakpad in order to build
up a map of regions covered by the unwind info so that we can later jump
to the right record when we need to unwind a specific function.

The actual parsing is relatively straight-forward, as the STACK CFI records
are just another (text) form of the eh_frame unwind instructions, and
the same goes for lldb's UnwindPlans. The newly-introduced
PostfixExpression API is used to convert the breakpad postfix
expressions into DWARF. The generated dwarf expressions are stored in a
BumpPtrAllocator, as the UnwindPlan does not take ownership of the
expression data it references (usually this is static data in an object
file, so special ownership is needed).

At this moment the generated unwind plans aren't used in the actual
unwind machinery (only in the image show-unwind command), but that is
coming in a separate patch.

Reviewers: amccarth, clayborg, markmentovai

Subscribers: aprantl, jasonmolenda, lldb-commits

Differential Revision: https://reviews.llvm.org/D61733

llvm-svn: 360574
2019-05-13 11:25:35 +00:00
Adrian Prantl 0e4c482124 Pass ConstString by value (NFC)
My apologies for the large patch. With the exception of ConstString.h
itself it was entirely produced by sed.

ConstString has exactly one const char * data member, so passing a
ConstString by reference is not any more efficient than copying it by
value. In both cases a single pointer is passed. But passing it by
value makes it harder to accidentally return the address of a local
object.

(This fixes rdar://problem/48640859 for the Apple folks)

Differential Revision: https://reviews.llvm.org/D59030

llvm-svn: 355553
2019-03-06 21:22:25 +00:00
Pavel Labath 841bea933b Breakpad: auto-detect path style of file entries
Summary:
This adds support for auto-detection of path style to SymbolFileBreakpad
(similar to how r351328 did the same for DWARF). We guess each file
entry separately, as we have no idea which file came from which compile
units (and different compile units can have different path styles). The
breakpad generates should have already converted the paths to absolute
ones, so this guess should be reasonable accurate, but as always with
these kinds of things, it is hard to give guarantees about anything.

In an attempt to bring some unity to the path guessing logic, I move the
guessing logic from inside SymbolFileDWARF into the FileSpec class and
have both symbol files use it to implent their desired behavior.

Reviewers: clayborg, lemo, JDevlieghere

Subscribers: aprantl, markmentovai, lldb-commits

Differential Revision: https://reviews.llvm.org/D57895

llvm-svn: 353702
2019-02-11 14:11:00 +00:00
Pavel Labath 3f35ab8b30 SymbolFileBreakpad: Add line table support
Summary:
This patch teaches SymbolFileBreakpad to parse the line information in
breakpad files and present it to lldb.

The trickiest question here was what kind of "compile units" to present
to lldb, as there really isn't enough information in breakpad files to
correctly reconstruct those.

A couple of options were considered
- have the entire file be one compile unit
- have one compile unit for each FILE record
- have one compile unit for each FUNC record

The main drawback of the first approach is that all of the files would
be considered "headers" by lldb, and so they wouldn't be searched if
target.inline-breakpoint-strategy=never. The single compile unit would
also be huge, and there isn't a good way to name it.

The second approach will create mostly correct compile units for cpp
files, but it will still be wrong for headers. However, the biggest
drawback here seemed to be the fact that this can cause a compile unit
to change mid-function (for example when a function from another file is
inlined or another file is #included into a function). While I don't
know of any specific thing that would break in this case, it does sound
like a thing that we should avoid.

In the end, we chose the third option, as it didn't seem to have any
major disadvantages, though it was not ideal either. One disadvantage
here is that this generates a large number of compile units, and there
is still a question on how to name it. We chose to simply name it after
the first line record in that function. This should be correct 99.99% of
the time, though it can produce somewhat strange results if the very
first line record comes from an #included file.

Reviewers: clayborg, zturner, lemo, markmentovai

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D56595

llvm-svn: 353404
2019-02-07 13:42:32 +00:00
Pavel Labath 5b18ddb6d1 BreakpadRecords: Address post-commit feedback
Summary:
This addresses the issues raised in D56844. It removes the accessors from the
breakpad record structures by making the fields public. Also, I refactor the
UUID parsing code to remove hard-coded constants.

Reviewers: lemo

Subscribers: clayborg, lldb-commits

Differential Revision: https://reviews.llvm.org/D57037

llvm-svn: 352021
2019-01-24 04:17:59 +00:00
Pavel Labath 06bb373559 breakpad: Add FUNC records to the symtab
This patch extends SymbolFileBreakpad::AddSymbols to include the symbols
from the FUNC records too. These symbols come from the debug info and
have a size associated with them, so they are given preference in case
there is a PUBLIC record for the same address.

To achieve this, I first pre-process the symbols into a temporary
DenseMap, and then insert the uniqued symbols into the module's symtab.

Reviewers: clayborg, lemo, zturner

Reviewed By: clayborg

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D56590

llvm-svn: 351781
2019-01-22 04:56:31 +00:00
Chandler Carruth 2946cd7010 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.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Pavel Labath 2cf5486ce4 Breakpad: Extract parsing code into a separate file
Summary:
This centralizes parsing of breakpad records, which was previously
spread out over ObjectFileBreakpad and SymbolFileBreakpad.

For each record type X there is a separate breakpad::XRecord class, and
an associated parse function. The classes just store the information in
the breakpad records in a more accessible form. It is up to the users to
determine what to do with that data.

This separation also made it possible to write some targeted tests for
the parsing code, which was previously unaccessible, so I write a couple
of those too.

Reviewers: clayborg, lemo, zturner

Reviewed By: clayborg

Subscribers: mgorny, fedor.sergeev, lldb-commits

Differential Revision: https://reviews.llvm.org/D56844

llvm-svn: 351541
2019-01-18 10:37:04 +00:00
Zachary Turner 576495e67b [SymbolFile] Remove SymbolContext parameter from FindTypes.
This parameter was only ever used with the Module set, and
since a SymbolFile is tied to a module, the parameter turns
out to be entirely unnecessary.  Furthermore, it doesn't make
a lot of sense to ask a caller to ask SymbolFile which is tied
to Module X to find types for Module Y, but that possibility
was open with the previous interface.  By removing this
parameter from the API, it makes it harder to use incorrectly
as well as easier for an implementor to understand what it
needs to do.

llvm-svn: 351133
2019-01-14 22:41:21 +00:00
Zachary Turner ce386e306d Fix build breaks after the ParseCompileUnit changes.
The addition of SymbolFileBreakpad crossed paths with my change,
so this interface needs to be fixed up as well.

llvm-svn: 350950
2019-01-11 18:35:58 +00:00
Pavel Labath 1cf23e1a37 Introduce SymbolFileBreakpad and use it to fill symtab
Summary:
This commit adds the glue code necessary to integrate the
SymbolFileBreakpad into the plugin system. Most of the methods are
stubbed out. The only method implemented method is AddSymbols, which
parses the PUBLIC "section" of the breakpad "object file", and fills out
the Module's symtab.

To enable testing this, I've made two additional changes:
- dump Symtab from the SymbolVendor class. The symtab was already being
  dumped as a part of the object file dump, but that happened before
  symbol vendor kicked in, so it did not reflect any symbols added
  there.
- add ability to explicitly specify the external symbol file in
  lldb-test (so that the object file could be linked with the breakpad
  symbol file). To make things simpler, I've changed lldb-test from
  consuming multiple inputs (and dumping their symbols) to having it
  just process a single file per invocation. This was not a problem
  since everyone was using it that way already.

Reviewers: clayborg, zturner, lemo, markmentovai, amccarth

Subscribers: mgorny, lldb-commits

Differential Revision: https://reviews.llvm.org/D56173

llvm-svn: 350924
2019-01-11 11:17:51 +00:00