It was revealed by D69260.
Tool crashed when scanned relocations in a object without a symbol table.
This patch teaches it either to handle such objects (when relocations
does not use symbols we do not need a symbol table to proceed)
or to show an appropriate error otherwise.
Differential revision: https://reviews.llvm.org/D69304
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
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
"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
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 194f16b3548bcb23a7f0fd638778ed72edd18d37)
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:
The directive defines a symbol as an group/local memory (LDS) symbol.
LDS symbols behave similar to common symbols for the purposes of ELF,
using the processor-specific SHN_AMDGPU_LDS as section index.
It is the linker and/or runtime loader's job to "instantiate" LDS symbols
and resolve relocations that reference them.
It is not possible to initialize LDS memory (not even zero-initialize
as for .bss).
We want to be able to link together objects -- starting with relocatable
objects, but possible expanding to shared objects in the future -- that
access LDS memory in a flexible way.
LDS memory is in an address space that is entirely separate from the
address space that contains the program image (code and normal data),
so having program segments for it doesn't really make sense.
Furthermore, we want to be able to compile multiple kernels in a
compilation unit which have disjoint use of LDS memory. In that case,
we may want to place LDS symbols differently for different kernels
to save memory (LDS memory is very limited and physically private to
each kernel invocation), so we can't simply place LDS symbols in a
.lds section.
Hence this solution where LDS symbols always stay undefined.
Change-Id: I08cbc37a7c0c32f53f7b6123aa0afc91dbc1748f
Reviewers: arsenm, rampitec, t-tye, b-sumner, jsjodin
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, rupprecht, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61493
llvm-svn: 364296
Summary:
When llvm-objcopy sorts sections during finalization, it only sorts based on the offset, which can cause the group section to come after the sections it contains. This causes link failures when using gold to link objects created by llvm-objcopy.
Fix this for now by copying GNU objcopy's behavior of placing SHT_GROUP sections first. In the future, we may want to remove this sorting entirely to more closely preserve the input file layout.
This fixes https://bugs.llvm.org/show_bug.cgi?id=42052.
Reviewers: jakehehrlich, jhenderson, MaskRay, espindola, alexshap
Reviewed By: MaskRay
Subscribers: phuongtrang148993, emaste, arichardson, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62620
llvm-svn: 362973
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 is https://bugs.llvm.org/show_bug.cgi?id=42122.
If an object file has a size less than program header's file [offset + size]
(i.e. if we have overflow), llvm-objcopy crashes instead of reporting a
error.
The patch fixes this issue.
Differential revision: https://reviews.llvm.org/D62898
llvm-svn: 362778
Without this, sectionWithinSegment() will return the wrong answer for bss
sections. This doesn't seem to matter now (for non-broken ELF files), but
it will matter with a change that I'm working on.
Differential Revision: https://reviews.llvm.org/D58426
llvm-svn: 361578
The code in ELF/Object.cpp is sometimes a bit hard to read because of
lots of auto used everywhere. The main intention of this patch is
to replace them with the real type for places where it is not obvious.
Also it cleanups few places.
It is NFC change, but I want to be sure that there is no objections to do that since it
is massive.
DIfferential revision: https://reviews.llvm.org/D62260
llvm-svn: 361466
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
.gnu_debuglink section contains information regarding file with
debugging symbols, identified by its CRC32. This target file is not
intended to ever change or it would invalidate the stored checksum, yet
the checksum is calculated over and over again for each of the objects
inside the archive, usually hundreds of times.
This patch precomputes the CRC32 of the target once and then reuses the
value where required, saving lots of redundant I/O.
The error message reported should stay the same, although now it might
be reported earlier.
Reviewed by: jhenderson, jakehehrlich, MaskRay
Differential Revision: https://reviews.llvm.org/D61343
Patch by Michal Janiszewski
llvm-svn: 360661
This is a fix for https://bugs.llvm.org/show_bug.cgi?id=41775,
Problem is in the final line:
Size += this->EntrySize;
I checked that we do not actually need it in this place,
since we always call removeSectionReferences which
calls removeSymbols which updates the Size.
But it worth to keep it, that allows to relax the dependencies.
Differential revision: https://reviews.llvm.org/D61636
llvm-svn: 360227
This is a fix for https://bugs.llvm.org/show_bug.cgi?id=41371.
Currently, it is possible to break the sh_link field of the dynamic relocation section
by removing the section it refers to. The patch fixes an issue and adds 2 test cases.
One of them shows that it does not seem possible to break the sh_info field.
I added an assert to verify this.
Differential revision: https://reviews.llvm.org/D60825
llvm-svn: 359552
llvm-objcopy currently emits an error if a section to be removed is
referenced by another section. This is a reasonable thing to do, but is
different to GNU objcopy. We should allow users who know what they are
doing to have a way to produce the invalid ELF. This change adds a new
switch --allow-broken-links to both llvm-strip and llvm-objcopy to do
precisely that. The corresponding sh_link field is then set to 0 instead
of an error being emitted.
I cannot use llvm-readelf/readobj to test the link fields because they
emit an error if any sections, like the .dynsym, cannot be properly
loaded.
Reviewed by: rupprecht, grimar
Differential Revision: https://reviews.llvm.org/D60324
llvm-svn: 358649
This patch fixes https://bugs.llvm.org/show_bug.cgi?id=41293 and
https://bugs.llvm.org/show_bug.cgi?id=41045. llvm-objcopy assumed that
it could always read a section header string table. This isn't the case
when the sections were previously all stripped, and the e_shstrndx field
was set to 0. This patch fixes this. It also fixes a double space in an
error message relating to this issue, and prevents llvm-objcopy from
adding extra space for non-existent section headers, meaning that
--strip-sections on the output of a previous --strip-sections run
produces identical output, simplifying the test.
Reviewed by: rupprecht, grimar
Differential Revision: https://reviews.llvm.org/D59989
llvm-svn: 357475
Summary:
BTW, STLExtras.h provides llvm::size() which is similar to std::size()
for random access iterators. However, if we prefer qualified
llvm::size(), the member function .size() will be more convenient.
Reviewers: jhenderson, jakehehrlich, rupprecht, grimar, alexshap, espindola
Reviewed By: grimar
Subscribers: emaste, arichardson, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60028
llvm-svn: 357347
llvm-objcopy previously knew nothing about data in segments that wasn't
covered by section headers, meaning that it wrote zeroes instead of what
was there. As it is possible for this data to be useful to the loader,
this patch causes llvm-objcopy to start preserving this data. Data in
sections that are explicitly removed continues to be written as zeroes.
This fixes https://bugs.llvm.org/show_bug.cgi?id=41005.
Reviewed by: jakehehrlich, rupprecht
Differential Revision: https://reviews.llvm.org/D59483
llvm-svn: 356919
Fix: r356853 + set AddressAlign to 4 in
Inputs/compress-debug-sections.yaml for the new group section introduced.
Original commit message:
Currently, llvm-objcopy incorrectly handles compression and decompression of the
sections from COMDAT groups, because we do not implement the
replaceSectionReferences for this type of the sections.
The patch does that.
Differential revision: https://reviews.llvm.org/D59638
llvm-svn: 356856
This patch fixes the reason of ubsan failure (UB detected)
happened after landing the D59638 (I had to revert it).
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap-ubsan/builds/11760/steps/check-llvm%20ubsan/logs/stdio)
Problem is the following. Our implementation of GroupSection assumes that
its address is 4 bytes aligned when writes it:
template <class ELFT>
void ELFSectionWriter<ELFT>::visit(const GroupSection &Sec) {
ELF::Elf32_Word *Buf =
reinterpret_cast<ELF::Elf32_Word *>(Out.getBufferStart() + Sec.Offset);
...
But the test case for D59638 did not set AddressAlign in YAML. So address was
not 4 bytes aligned since Sec.Offset was odd. That triggered the issue.
This patch teaches llvm-objcopy to report an error for such sections (which should
not met in reality), what is better than having UB.
Differential revision: https://reviews.llvm.org/D59695
llvm-svn: 356853
Currently, llvm-objcopy incorrectly handles compression and decompression of the
sections from COMDAT groups, because we do not implement the
replaceSectionReferences for this type of the sections.
The patch does that.
Differential revision: https://reviews.llvm.org/D59638
llvm-svn: 356738
If the compression was used and we had a symbol not involved in relocation,
we never updated its section and it was silently removed from the output.
Differential revision: https://reviews.llvm.org/D59542
llvm-svn: 356554
This fixes the https://bugs.llvm.org/show_bug.cgi?id=40980.
Previously if string optimization occurred as a result of
StringTableBuilder's finalize() method, the size wasn't updated.
This hopefully also makes the interaction between sections during finalization
processes a bit more clear.
Differential revision: https://reviews.llvm.org/D59488
llvm-svn: 356371
When --compress-debug-sections is given,
llvm-objcopy removes the uncompressed sections and adds compressed to the section list.
This makes all the pointers to old sections to be outdated.
Currently, code already has logic for replacing the target sections of the relocation
sections. But we also have to update the relocations by themselves.
This fixes https://bugs.llvm.org/show_bug.cgi?id=40885.
Differential revision: https://reviews.llvm.org/D58960
llvm-svn: 355821
We should create CompressedSection only if the section has SHF_COMPRESSED flag
or it's name starts from '.zdebug'.
Currently, we create it if section's data starts from ZLIB signature.
Differential revision: https://reviews.llvm.org/D59018
llvm-svn: 355501
