As for now, llvm-objcopy sorts section headers according to the offsets
of the sections in the input file. That can corrupt section references
in the dynamic symbol table because it is a loadable section and as such
is not updated by the tool. Even though the section references are not
required for loading the binary correctly, they are still handy for a
user who analyzes the file.
While the patch removes global reordering of section headers, it layouts
the sections in the same way as before, i.e. according to their original
offsets. All that helps the output file to resemble the input better.
Note that the patch removes sorting SHT_GROUP sections to the start of
the list, which was introduced in D62620 in order to ensure that they
come before the group members, along with the corresponding test. The
original issue was caused by the sorting of section headers, so dropping
the sorting also resolves the issue.
Differential Revision: https://reviews.llvm.org/D107653
During reviewing D102277 it was decided to remove lazy options processing
from llvm-objcopy CopyConfig structure. This patch transforms processing of ELF
lazy options into the in-place processing.
Differential Revision: https://reviews.llvm.org/D103260
This patch prepares llvm-objcopy to move its implementation
into a separate library. To make it possible it is necessary
to minimize internal dependencies.
Differential Revision: https://reviews.llvm.org/D99055
This patch removes creation of the resulting file from the
executeObjcopyOnBinary() function. For the most use cases, the
executeObjcopyOnBinary receives output file as a parameter
- raw_ostream &Out. The splitting .dwo file is implemented differently:
file containg .dwo tables is created inside executeObjcopyOnBinary().
When objcopy functionality would be moved into separate library,
current implementation will become inconvenient. The goal of that
refactoring is to separate concerns: It might be convenient to
to do dwo tables splitting but to create resulting file differently.
Differential Revision: https://reviews.llvm.org/D98582
During D88827 it was requested to remove the local implementation
of Memory/File Buffers:
// TODO: refactor the buffer classes in LLVM to enable us to use them here
// directly.
This patch uses raw_ostream instead of Buffers. Generally, using streams
could allow us to reduce memory usages. No need to load all data into the
memory - the data could be streamed through a smaller buffer.
Thus, this patch uses raw_ostream as an interface for output data:
Error executeObjcopyOnBinary(CopyConfig &Config,
object::Binary &In,
raw_ostream &Out);
Note 1. This patch does not change the implementation of Writers
so that data would be directly stored into raw_ostream.
This is assumed to be done later.
Note 2. It would be better if Writers would be implemented in a such way
that data could be streamed without seeking/updating. If that would be
inconvenient then raw_ostream could be replaced with raw_pwrite_stream
to have a possibility to seek back and update file headers.
This is assumed to be done later if necessary.
Note 3. Current FileOutputBuffer allows using a memory-mapped file.
The raw_fd_ostream (which could be used if data should be stored in the file)
does not allow us to use a memory-mapped file. Memory map functionality
could be implemented for raw_fd_ostream:
It is possible to add resize() method into raw_ostream.
class raw_ostream {
void resize(uint64_t size);
}
That method, implemented for raw_fd_ostream, could create a memory-mapped file.
The streamed data would be written into that memory file then.
Thus we would be able to use memory-mapped files with raw_fd_ostream.
This is assumed to be done later if necessary.
Differential Revision: https://reviews.llvm.org/D91028
This diff introduces --keep-undefined in llvm-objcopy/llvm-strip for Mach-O
which makes the tools preserve undefined symbols.
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D97040
The few options are niche. They solved a problem which was traditionally solved
with more shell commands (`llvm-readelf -n` fetches the Build ID. Then
`ln` is used to hard link the file to a directory derived from the Build ID.)
Due to limitation, they are no longer used by Fuchsia and they don't appear to
be used elsewhere (checked with Google Search and Debian Code Search). So delete
them without a transition period.
Announcement: https://lists.llvm.org/pipermail/llvm-dev/2021-February/148446.html
Differential Revision: https://reviews.llvm.org/D96310
This matches behavior GNU objcopy and can simplify clang-offload-bundler
(which currently works around the issue by invoking llvm-objcopy twice).
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D90438
Remove usages of special error reporting functions(error(),
reportError()). Errors are reported as Expected<>/Error returning
values. This part is for ELF subfolder of llvm-objcopy.
Testing: check-all.
Differential Revision: https://reviews.llvm.org/D87987
This patch resolves crash that occurs when user wanted to remove all
symbols and add a brand new one using:
```
llvm-objcopy -R .symtab --add-symbol foo=1234 in.o out.o
```
Before these changes the symbol table internally being null when adding
new symbols. For now we will regenerate symtab in this case.
This fixes: https://bugs.llvm.org/show_bug.cgi?id=43930
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D82935
Reorder `DumpSection` under `handleArgs` in file `ELFObjcopy.cpp`.
`DumpSection` is placed before `replaceAndRemoveSections` and is
therefore now the first operation under `handleArgs`. Thus, it is now
performed before both `add` and `remove` section operations.
Change for the MachO format at D81123. Together fixes https://bugs.llvm.org/show_bug.cgi?id=44283.
Reviewed By: alexshap, jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D81097
cctools strip has the option "-T" which removes Swift symbols.
This diff implements this option in llvm-strip for MachO.
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D80099
Don't error on Config.KeepFileSymbols for COFF and Mach-O.
Original description:
GNU objcopy removes STT_FILE symbols for strip-debug operations, and
keeps them for --discard-all operation. Match their behaviour for
llvm-objcopy.
Bug: https://github.com/android/ndk/issues/1212
Differential Revision: https://reviews.llvm.org/D76675
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
--only-keep-debug produces a debug file as the output that only
preserves contents of sections useful for debugging purposes (the
binutils implementation preserves SHT_NOTE and non-SHF_ALLOC sections),
by changing their section types to SHT_NOBITS and rewritting file
offsets.
See https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
The intended use case is:
```
llvm-objcopy --only-keep-debug a a.dbg
llvm-objcopy --strip-debug a b
llvm-objcopy --add-gnu-debuglink=a.dbg b
```
The current layout algorithm is incapable of deleting contents and
shrinking segments, so it is not suitable for implementing the
functionality.
This patch adds a new algorithm which assigns sh_offset to sections
first, then modifies p_offset/p_filesz of program headers. It bears a
resemblance to lld/ELF/Writer.cpp.
Reviewed By: jhenderson, jakehehrlich
Differential Revision: https://reviews.llvm.org/D67137
This works around a bug in Debian's patchset for glibc. The bug is
described in detail in the upstream debian bug:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=943798, but the short
version of it is that glibc on any Debian based distro don't load
libraries unless it has a .ARM.attribute section.
Reviewed by: jhenderson, rupprecht, MaskRay, jakehehrlich
Differential Revision: https://reviews.llvm.org/D69188
Patch by Tobias Hieta.
Exposed by D69041. If SHT_SYMTAB does not exist, ELFObjcopy.cpp:handleArgs will crash due
to a null pointer dereference.
for (const NewSymbolInfo &SI : Config.ELF->SymbolsToAdd) {
...
Obj.SymbolTable->addSymbol(
Fix this by creating .symtab and .strtab on demand in ELFBuilder<ELFT>::readSections,
if --add-symbol is specified.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D69093
llvm-svn: 375105
Fixes PR43181. This option was recently added to GNU objcopy (binutils
PR24942).
`llvm-objcopy -I binary -O elf64-x86-64 --set-section-alignment .data=8` can set the alignment of .data.
Reviewed By: grimar, jhenderson, rupprecht
Differential Revision: https://reviews.llvm.org/D67656
llvm-svn: 373461
GNU objcopy documents that -B is only useful with architecture-less
input (i.e. "binary" or "ihex"). After D67144, -O defaults to -I, and
-B is essentially a NOP.
* If -O is binary/ihex, GNU objcopy ignores -B.
* If -O is elf*, -B provides the e_machine field in GNU objcopy.
So to convert a blob to an ELF, `-I binary -B i386:x86-64 -O elf64-x86-64` has to be specified.
`-I binary -B i386:x86-64 -O elf64-x86-64` creates an ELF with its
e_machine field set to EM_NONE in GNU objcopy, but a regular x86_64 ELF
in elftoolchain elfcopy. Follow the elftoolchain approach (ignoring -B)
to simplify code. Users that expect their command line portable should
specify -B.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D67215
llvm-svn: 371914
Handle --prefix-alloc-sections after --rename-sections so that --prefix-alloc-sections code
does not have to check if renaming has been performed.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D66931
llvm-svn: 371591
"Section" can refer to the type llvm::objcopy:🧝:Section or the
variable name. Rename it to "Sec" for clarity. "Sec" is already used a
lot, so this change improves consistency as well.
Also change `auto` to `const SectionBase` for readability.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D67143
llvm-svn: 370852
Summary:
GNU --strip-unneeded strips debugging sections as well. Do that for llvm-objcopy as well.
Additionally, add a test that verifies we keep the .gnu_debuglink section. This apparently was not always the case, and I'm not sure which commit fixed it, but there doesn't appear to be any test coverage to make sure we continue to do so.
This fixes PR41043.
Reviewers: jhenderson, jakehehrlich, espindola, alexshap
Subscribers: emaste, arichardson, MaskRay, abrachet, seiya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66623
llvm-svn: 369761
Summary:
The matchers for section/symbol related flags (e.g. `--keep-symbol=Name` or `--regex --keep-symbol=foo.*`) are currently just vectors that are matched linearlly. However, adding wildcard support would require negative matching too, e.g. a symbol should be removed if it matches a wildcard *but* doesn't match some other wildcard.
To make the next patch simpler, consolidate matching logic to a class defined in CopyConfig that takes care of matching.
Reviewers: jhenderson, seiya, MaskRay, espindola, alexshap
Reviewed By: jhenderson, MaskRay
Subscribers: emaste, arichardson, jakehehrlich, abrachet, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66432
llvm-svn: 369689
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
This reverts r365193 (git commit 194f16b354)
This patch doesn't work with binaries built w/ `--emit-relocs`, e.g.
```
$ echo 'int main() { return 0; }' | clang -Wl,--emit-relocs -x c - -o foo && llvm-objcopy --strip-unneeded foo
llvm-objcopy: error: 'foo': not stripping symbol '__gmon_start__' because it is named in a relocation
```
llvm-svn: 365712
Summary:
Use an enum instead of string to hold the output file format in Config.InputFormat and Config.OutputFormat. It's essential to support other output file formats other than ELF.
This patch originally has been submitted as D63239. However, there was an use-of-uninitialized-value bug and reverted in r364379 (git commit 4ee933c).
This patch includes the fix for the bug by setting Config.InputFormat/Config.OutputFormat in parseStripOptions.
Reviewers: espindola, alexshap, rupprecht, jhenderson
Reviewed By: jhenderson
Subscribers: emaste, arichardson, jakehehrlich, MaskRay, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64170
llvm-svn: 365173
This reverts r364254 (git commit 545f001d1b)
This change causes some llvm-obcopy tests to fail with valgrind.
Following is the output for basic-keep.test
Command Output (stderr):
--
==107406== Conditional jump or move depends on uninitialised value(s)
==107406== at 0x1A30DD: executeObjcopy(llvm::objcopy::CopyConfig const&) (llvm-objcopy.cpp:235)
==107406== by 0x1A3935: main (llvm-objcopy.cpp:294)
llvm-svn: 364379
Summary:
Use an enum instead of string to hold the output file format in Config.InputFormat and Config.OutputFormat. It's essential to support other output file formats other than ELF.
Reviewers: espindola, alexshap, rupprecht, jhenderson
Reviewed By: rupprecht, jhenderson
Subscribers: jyknight, compnerd, emaste, arichardson, fedor.sergeev, jakehehrlich, MaskRay, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63239
llvm-svn: 364254
This implements the functionality described in
https://lld.llvm.org/Partitions.html. It works as follows:
- Reads the section headers using the ELF header at file offset 0;
- If extracting a loadable partition:
- Finds the section containing the required partition ELF header by looking it up in the section table;
- Reads the ELF and program headers from the section.
- If extracting the main partition:
- Reads the ELF and program headers from file offset 0.
- Filters the section table according to which sections are in the program headers that it read:
- If ParentSegment != nullptr or section is not SHF_ALLOC, then it goes in.
- Sections containing partition ELF headers or program headers are excluded as there are no headers for these in ordinary ELF files.
Differential Revision: https://reviews.llvm.org/D62364
llvm-svn: 362818
This patch brings various error messages into line with each other, by
removing trailing full stops, and making the first letter lower-case.
This addresses https://bugs.llvm.org/show_bug.cgi?id=40859.
Reviewed by: jhenderson, rupprecht, jakehehrlich
Differential Revision: https://reviews.llvm.org/D62072
Patch by Alex Brachet
llvm-svn: 361384
Igor Kudrin