Commit Graph

10 Commits

Author SHA1 Message Date
Pavel Labath bca95f8acc Add a comment explaining how the input for GetModuleSpecifications_EarlySectionHeaders was generated
Davide pointed out this would be useful if the file ever needs to be
regenerated (and I certainly agree).

I also replace the test binary with a slightly smaller one -- I intended
to do this in the original commit, but I forgot to add it to the patch
as I was juggling several things at the same time.

llvm-svn: 324256
2018-02-05 18:03:02 +00:00
Pavel Labath 4f0331251f Fix parsing of object files with "early" section headers
ObjectFileELF::GetModuleSpecifications contained a lot of tip-toing code
which was trying to avoid loading the full object file into memory. It
did this by trying to load data only up to the offset if was accessing.
However, in practice this was useless, as 99% of object files we
encounter have section headers at the end, so we would load the whole
file as soon as we start parsing the section headers.

In fact, this would break as soon as we encounter a file which does
*not* have section headers at the end (yaml2obj produces these), as the
access to .strtab (which we need to get the section names) was not
guarded by this offset check.

As this strategy was completely ineffective anyway, I do not attempt to
proliferate it further by guarding the .strtab accesses. Instead I just
lead the full file as soon as we are reasonably sure that we are indeed
processing an elf file.

If we really care about the load size here, we would need to reimplement
this to just load the bits of the object file we need, instead of
loading everything from the start of the object file to the given
offset. However, given that the OS will do this for us for free when
using mmap, I think think this is really necessary.

For testing this I check a (tiny) SO file instead of yaml2obj-ing it
because the fact that they come out first is an implementation detail of
yaml2obj that can change in the future.

llvm-svn: 324254
2018-02-05 17:25:40 +00:00
Pavel Labath e2867bc4a0 ObjectFileELF: Add support for compressed sections
Summary:
We use the llvm decompressor to decompress SHF_COMPRESSED sections. This enables
us to read data from debug info sections, which are sometimes compressed,
particuarly in the split-dwarf case.  This functionality is only available if
llvm is compiled with zlib support.

Reviewers: clayborg, zturner

Subscribers: emaste, mgorny, aprantl, lldb-commits

Differential Revision: https://reviews.llvm.org/D40616

llvm-svn: 320813
2017-12-15 14:23:58 +00:00
Tim Hammerquist a6db41675c cmake + xcode: prevent gtests from using includes from project root
Summary:
At present, several gtests in the lldb open source codebase are using
#include statements rooted at $(SOURCE_ROOT)/${LLDB_PROJECT_ROOT}.

This patch cleans up this directory/include structure for both CMake and
Xcode build systems.

rdar://problem/33835795

Reviewers: zturner, jingham, beanz

Reviewed By: beanz

Subscribers: emaste, lldb-commits, mgorny

Differential Revision: https://reviews.llvm.org/D36598

llvm-svn: 314849
2017-10-03 21:20:18 +00:00
Vedant Kumar e7d85688c6 [unittests] Speculative fix for changes introduced in rL313156
llvm-svn: 313181
2017-09-13 20:02:24 +00:00
Pavel Labath 7ed3e22f00 [unittests] Add a helper function for getting an input file
Summary:
Fetching an input file required about five lines of code, and this was
repeated in multiple unit tests, with slight variations. Add a helper
function for doing that into the lldbUtilityMocks module (which I rename
to lldbUtilityHelpers to commemorate the fact it includes more than
mocks)

Reviewers: zturner, eugene

Subscribers: emaste, mgorny, lldb-commits

Differential Revision: https://reviews.llvm.org/D34683

llvm-svn: 306668
2017-06-29 13:02:11 +00:00
Pavel Labath efddda3d8d ObjectFileELF: Fix symbol lookup in bss section
Summary:
If we have symbol information in a separate file, we need to be very
careful about presenting a unified section view of module to the rest of
the debugger. ObjectFileELF had code to handle that, but it was being
overly cautious -- the section->GetFileSize()!=0 meant that the
unification would fail for sections which do not occupy any space in the
object file (e.g., .bss). In my case, that manifested itself as not
being able to display the values of .bss variables properly as the
section associated with the variable did not have it's load address set
(because it was not present in the unified section list).

I test this by making sure the unified section list and the variables
refer to the same section.

Reviewers: eugene, zturner

Subscribers: tberghammer, lldb-commits, mgorny

Differential Revision: https://reviews.llvm.org/D32434

llvm-svn: 301917
2017-05-02 12:40:31 +00:00
Zachary Turner 666cc0b291 Move DataBuffer / DataExtractor and friends from Core -> Utility.
llvm-svn: 296943
2017-03-04 01:30:05 +00:00
Chris Bieneman bc9d0cd925 [CMake] Add explicit dependencies for ObjectFileELF tests
llvm-svn: 294372
2017-02-07 23:33:58 +00:00
Pavel Labath 23ccc29197 Open ELF core dumps with more than 64K sections
Summary:
Problem:

There are three filelds in the ELF header - e_phnum, e_shnum, and e_shstrndx -
that could be bigger than 64K and therefore do not fit in 16 bits reserved for
them in the header. If this happens, pretty often there is a special section at
index 0 which contains their real values for these fields in the section header
in the fields sh_info, sh_size, and sh_link respectively.

Fix:

- Rename original fields in the header declaration. We want to have them around
just in case.

- Reintroduce these fields as 32-bit members at the end of the header. By default
they are initialized from the header in Parse() method.

- In Parse(), detect the situation when the header might have been extended into
section info #0 and try to read it from the same data source.

- ObjectFileELF::GetModuleSpecifications accesses some of these fields but the
original parse uses too small data source. Re-parse the header if necessary
using bigger data source.

- ProcessElfCore::CreateInstance uses header with potentially sentinel values,
but it does not access these fields, so a comment here is enough.

Reviewers: labath

Reviewed By: labath

Subscribers: davidb, lldb-commits, mgorny

Differential Revision: https://reviews.llvm.org/D29095
Author: Eugene Birukov <eugenebi@hotmail.com>

llvm-svn: 293714
2017-01-31 23:09:46 +00:00