The request is mentioned on D129053. I feel that having this functionality is
mildly useful (not strong).
* Rename .ctors to .init_array and change sh_type to SHT_INIT_ARRAY (GNU objcopy
detects the special name but we don't).
* Craft tests for a new SHT_LLVM_* extension
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D129337
* GNU objcopy supports --set-section-flags src=... --rename-section src=tst and --set-section-flags runs first.
* GNU objcopy processes --update-section before --rename-section.
To match the two behaviors, postpone --rename-section and allow its use together
with --set-section-flags.
As a side effect, --rename-section=.foo1=.foo2 --add-section=.foo1=/dev/null
leads to .foo2 while GNU objcopy surprisingly produces .foo1 (so
--set-section-flags --add-section --rename-section do not form a total order).
I think the deviation is fine as a total order makes more sense.
Rename set-section-flags-and-rename.test to
set-section-attr-and-rename.test and additionally test --set-section-alignment
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D129336
For a SHT_NOBITS section like .bss, its sh_offset is typically not
aligned by sh_addralign. If it is converted to SHT_PROGBITS by
`--set-section-flags .bss=alloc,contents`, we should conceptually align
it when computing the output size for -O binary. Otherwise the output
size may be smaller than GNU objcopy produced output.
* binary-no-paddr.test has a case with non-sensical p_paddr=1 which has
a changed behavior. Update it.
Close https://github.com/llvm/llvm-project/issues/55246
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D128961
clang 14 removed -gz=zlib-gnu support and ld.lld removed linker input support
for zlib-gnu in D126793. Now let's remove zlib-gnu from llvm-objcopy.
* .zdebug* sections are no longer recognized as debug sections. --strip* don't remove them.
They are copied like other opaque sections
* --decompress-debug-sections does not uncompress .zdebug* sections
* --compress-debug-sections=zlib-gnu is not supported
It is very rare but in case a user has object files using .zdebug . They can use
llvm-objcopy<15 or GNU objcopy for uncompression.
--compress-debug-sections=zlib-gnu is unlikely ever used by anyone, so I do not
add a custom diagnostic.
Differential Revision: https://reviews.llvm.org/D128688
STB_GNU_UNIQUE is like STB_GLOBAL with extra semantics:
* gold and ld.lld: changed to STB_GLOBAL if --no-gnu-unique is specified
* glibc: unique even with dlopen `RTLD_LOCAL`, implies DF_1_NODELETE
Therefore, I think it makes sense for --weaken-symbol/--weaken-symbols/--weaken
to change STB_GNU_UNIQUE symbols.
binutils 2.39 will have the same behavior: https://sourceware.org/bugzilla/show_bug.cgi?id=28926
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D120638
Current objcopy implementation has a possibility to add or update sections.
The incoming section is specified as a pair: section name and name of the file
containing section data. The interface does not allow to specify incoming
section as a memory buffer. This patch adds possibility to specify incoming
section as a memory buffer.
Differential Revision: https://reviews.llvm.org/D120486
Mapping symbols are required by ARM/AArch64 ELF ABI. They help to
disassemble files correctly and are also used in linkers. Nonetheless,
for executable files, the symbols can be stripped to better resemble
the behavior of GNU's objcopy.
Differential Revision: https://reviews.llvm.org/D117233
MIPS64 little endian target has a "special" encoding of `r_info`
relocation record field. Instead of one 64-bit little endian number, it
is a little endian 32-bit number followed by a 32-bit big endian number.
For correct reading and writing such fields we must provide information
about target machine into the corresponding routine. This patch does
this for the `llvm-objcopy` tool and fix handling of MIPS64 little
endian files.
The bug was reported in the issue #52647.
Differential Revision: https://reviews.llvm.org/D115635
This is another attempt at D59351 which attempted to add --update-section, but
with some heuristics for adjusting segment/section offsets/sizes in the event
the data copied into the section is larger than the original size of the section.
We are opting to not support this case. GNU's objcopy was able to do this because
the linker and objcopy are tightly coupled enough that segment reformatting was
simpler. This is not the case with llvm-objcopy and lld where they like to be separated.
This will attempt to copy data into the section without changing any other
properties of the parent segment (if the section is part of one).
Differential Revision: https://reviews.llvm.org/D112116
As for now, llvm-objcopy renames only sections that are specified
explicitly in --rename-section, while GNU objcopy keeps names of
relocation sections in sync with their targets. For example:
> readelf -S test.o
...
[ 1] .foo PROGBITS
[ 2] .rela.foo RELA
> objcopy --rename-section .foo=.bar test.o gnu.o
> readelf -S gnu.o
...
[ 1] .bar PROGBITS
[ 2] .rela.bar RELA
> llvm-objcopy --rename-section .foo=.bar test.o llvm.o
> readelf -S llvm.o
...
[ 1] .bar PROGBITS
[ 2] .rela.foo RELA
This patch makes llvm-objcopy to match the behavior of GNU objcopy better.
Differential Revision: https://reviews.llvm.org/D110352
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
See [GRP_COMDAT group with STB_LOCAL signature](https://groups.google.com/g/generic-abi/c/2X6mR-s2zoc)
objcopy PR: https://sourceware.org/bugzilla/show_bug.cgi?id=27931
GRP_COMDAT deduplication is purely based on the signature symbol name in
ld.lld/GNU ld/gold. The local/global status is not part of the equation.
If the signature symbol is localized by --localize-hidden or
--keep-global-symbol, the intention is likely to make the group fully
localized. Drop GRP_COMDAT to suppress deduplication.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D106782
There is no need to differentiate whether `UseSegments` is true or
false. Unifying the cases makes the behavior closer to BinaryWriter.
This improves compatibility with objcopy because SHF_ALLOC sections not in
a PT_LOAD will not be skipped. Such cases are usually erroneous input, though.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D104186
IHexWriter was evaluating a section's physical address when deciding if
that section should be written to an output. This approach does not
account for a zero-sized section that has the same physical address as a
sized section. The behavior varies from GNU objcopy, and may result in a
HEX file that does not include all program sections.
The IHexWriter now excludes zero-sized sections when deciding what
should be written to the output. This affects the contents of the
writer's `Sections` collection; we will not try to insert multiple
sections that could have the same physical address. The behavior seems
consistent with GNU objcopy, which always excludes empty sections,
no matter the address.
The new test case evaluates the IHexWriter behavior when provided a
variety of empty sections that overlap or append a filled section. See
the input file's comments for more information. Given that test input,
and the change to the IHexWriter, GNU objcopy and llvm-objcopy produce
the same output.
Reviewed By: jhenderson, MaskRay, evgeny777
Differential Revision: https://reviews.llvm.org/D101332
PR50160: we currently ignore non-PT_PHDR segments with no sections, not
accounting for its p_offset and p_filesz: this can cause an out-of-bounds write
in `writeSegmentData` if the p_offset+p_filesz is larger than the total file
size.
This can be fixed by setting p_offset=p_filesz=0. The logic nicely unifies with
the logic added in D90897.
Reviewed By: jhenderson, rupprecht
Differential Revision: https://reviews.llvm.org/D101560
Fix PR45416: the diagnostic when '=' is missing is misleading.
`FileOutputBuffer::create` returns successfully when the filename is empty
(the temporary file is `.tmp%%%%%%%`), but `FileOutputBuffer::commit` will error when
renaming `.tmp%%%%%%%` to the empty name).
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D101697
The code was using the standard isalnum function which doesn't handle
values outside the non-ascii range. Switching to using llvm::isAlnum
instead ensures we don't provoke undefined behaviour, which can in some
cases result in crashes.
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D97663
The test was showing that when --strip-unneeded is specified for an
executable, all the symbols are stripped. However, the set of symbols
used in the test would be stripped by --strip-unneeded for an ET_REL
object too. Fix this by adding additional symbols that aren't normally
stripped by --strip-unneeded.
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D97664
This patch adds a number of new test cases that cover various
llvm-objcopy and llvm-strip features that had missing test coverage of
various descriptions:
* --add-section - checked the shdr properties, not just the content.
* Dedicated test case for --add-symbol when there are many sections.
* Show that --change-start accepts negative values without overflow.
This was previously present but got lost between review versions.
* --dump-section - show that multiple sections can be dumped
simultaneously to different files, and that an error is reported when
a section cannot be found.
* --globalize-symbol(s) - show that symbols that are not mentioned are
not globalized, if they would otherwise be, and that missing symbols
from the list do not cause problems.
* --keep-global-symbol - show that the --regex option can be used in
conjunction with this option.
* --keep-symbol - show that the --regex option can be used in
conjunction with this option.
* --localize-symbol(s) - show that symbols that are not mentioned are
not localized, if they would otherwise be, and that missing symbols
from the list do not cause problems.
* --prefix-alloc-sections - show the behaviour of an empty string
argument and multiple arguments.
* --prefix-symbols - show the behaviour of an empty string argument and
multiple arguments. Also show the option applies to undefined symbols.
* --redefine-symbol - show that symbols with no name can be renamed,
that it is not an error if a symbol is not specified, and that the
option doesn't chain (i.e. --redefine-sym a=b --redefine-sym b=c does
not redefine a as c).
* --rename-section - show that all section flags are preserved if none
are specified. Also show that the option does not chain.
* --set-section-alignment - show that only specified sections have
their alignments changed.
* --set-section-flags - show which section flags are preserved when this
option is used. Also show that unspecified sections are not affected.
* --preserve-dates - show that -p is an alias of --preserve-dates.
* --strip-symbol - show that --regex works with this option for
llvm-objcopy as well as llvm-strip.
* --strip-unneeded-symbol(s) - show more clearly that needed symbols are
not stripped even if requested by this option.
* --allow-broken-links - show the sh_link of a symbol table is set to 0
when its string table has been removed when this option is specified.
* --weaken-symbol(s) - show that symbols that are not mentioned are not
weakened, if they would otherwise be, and that missing symbols from
the list do not cause problems.
* --wildcard - show the wildcard behaviour for several options that were
previously unchecked.
Reviewed by: alexshap
Differential Revision: https://reviews.llvm.org/D97666
The check for whether an extended symbol index table was required
dropped the first SHN_LORESERVE sections from the sections array before
checking whether the remaining sections had symbols. Unfortunately, the
null section header is not present in this list, so the check was
skipping the first section that might be important. If that section
contained a symbol, and no subsequent ones did, the .symtab_shndx
section would not be emitted, leading to a corrupt object.
Also consolidate and expand test coverage in the area to cover this bug
and other aspects of the SYMTAB_SHNDX section.
Reviewed by: alexshap, MaskRay
Differential Revision: https://reviews.llvm.org/D97661
Additionally do some test tidy-ups and improve coverage of symbol
section indexes where the logical section index >= SHN_LORESERVE.
The symbol and section names in the many-section input object were
mostly shared. This patch changes them to be distinct, enabling
different operations such as --add-symbol, to be more targeted, when
using the object. It also makes the test less confusing and removes some
oddness in the symbol table order, presumably caused by the duplicate
names.
The input object was built from assembly that was of the form:
.section s1
sym1:
.section s2
sym2:
...
with a total of 65536 such occurrences. llvm-objcopy was then used to
remove the empty .text section automatically generated by MC, and
incidentally to move .strtab to the end of the object. This ensured that
the section/symbol indexes matched their name (i.e. section index 1 was
s1, section index 2 was s2 etc, and sym1 was in s1, sym2 in s2 etc).
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D97660
This makes the behavior similar to cp
```
chmod u+s,g+s,o+x a
sudo llvm-strip a -o b
// With this patch, b drops set-user-ID and set-group-ID bits.
// sudo cp a b => b does not have set-user-ID or set-group-ID bits.
```
This also changes the behavior for the following case:
```
chmod u+s,g+s,o+x a
llvm-strip a
// a preserves set-user-ID and set-group-ID bits.
// This matches binutils<2.36 and probably >=2.37. 2.36 and 2.36.1 have some compatibility issues.
```
Differential Revision: https://reviews.llvm.org/D97253
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 is consistent with BFD objcopy.
Previously llvm objcopy would allocate space for SHT_NOBITS sections
often resulting in enormous binary files.
New test case (binary-paddr.test %t6).
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D95569
On z/OS, the following error message is not matched correctly in lit tests.
```
EDC5129I No such file or directory.
```
This patch uses a lit config substitution to check for platform specific error messages.
Reviewed By: muiez, jhenderson
Differential Revision: https://reviews.llvm.org/D95246
We already set the `sh_entsize` field in a single place
for all non-implicit sections.
This patch reorders the logic slightly and with it
we finally have the only one place where the `sh_entsize` is set.
obj2yaml will not dump the `EntSize` key for `SHT_DYNSYM/SHT_SYMTAB` sections anymore,
when the value of `sh_entsize` is equal to `sizeof(Elf_Sym)`
Note that this also seems revealed an issue in llvm-objcopy:
Previously yaml2obj set the `sh_entsize` for the `.symtab` section to 0x18,
now we it sets it for `SHT_SYMTAB` sections, i.e. by type.
But the `llvm-objcopy/ELF/only-keep-debug.test` has a `.symtab` section of type `SHT_STRTAB`,
and now yaml2obj sets the `sh_entsize` to 0 for it.
I had to update the corresponding check lines for `ES`, but the behavior of
`llvm-objcopy` should be fixed instead I think.
I've added a TODO and a comment.
Differential revision: https://reviews.llvm.org/D95364
On z/OS, the following error message is not matched correctly in lit tests. This patch updates the CHECK expression to match successfully.
```
EDC5129I No such file or directory.
```
Reviewed By: muiez
Differential Revision: https://reviews.llvm.org/D94239
Alternative to D74755. sectionWithinSegment() treats an empty section as having
a size of 1. Due to the rule, an empty .tdata will not be attributed to an
empty PT_TLS. (The empty p_align=64 PT_TLS is for Android Bionic's TCB
compatibility (ELF-TLS). See https://reviews.llvm.org/D62055#1507426)
Currently --only-keep-debug will not layout a segment with no section
(layoutSegmentsForOnlyKeepDebug()), thus p_offset of PT_TLS can go past the end
of the file. The strange p_offset can trigger validation errors for subsequent
tools, e.g. llvm-objcopy errors when reading back the separate debug file
(readProgramHeaders()).
This patch places such an empty segment according to its parent segment. This
special cases works for the empty PT_TLS used in Android. For a non-empty
segment, it should have at least one non-empty section and will be handled by
the normal code. Note, p_memsz PT_LOAD is rejected by both Linux and FreeBSD.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D90897
Imagine we have a YAML declaration of few sections: `foo1`, `<unnamed 2>`, `foo3`, `foo4`.
To put them into segment we can do (1*):
```
Sections:
- Section: foo1
- Section: foo4
```
or we can use (2*):
```
Sections:
- Section: foo1
- Section: foo3
- Section: foo4
```
or (3*) :
```
Sections:
- Section: foo1
## "(index 2)" here is a name that we automatically created for a unnamed section.
- Section: (index 2)
- Section: foo3
- Section: foo4
```
It looks really confusing that we don't have to list all of sections.
At first I've tried to make this rule stricter and report an error when there is a gap
(i.e. when a section is included into segment, but not listed explicitly).
This did not work perfect, because such approach conflicts with unnamed sections/fills (see (3*)).
This patch drops "Sections" key and introduces 2 keys instead: `FirstSec` and `LastSec`.
Both are optional.
Differential revision: https://reviews.llvm.org/D90458
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
Currently `--relocations` ignores section symbol names and always prints
section names for them. This is inconsistent with GNU readelf and with `--symbols`.
We have a code in `getFullSymbolName` (which is used for `--symbols`) which can be
reused for `getRelocationTarget` (used for `--relocations`).
With that the issue described is fixed and code becomes a bit shorter.
Also with this change we start to print more relocations (in situations when we just
showed warnings instead before) and also start to report more diagnostic warnings
(see reloc-zero-name-or-value.test).
Differential revision: https://reviews.llvm.org/D87613
In this diff the tests which verify version printing functionality are refactored.
Since they are not specific to a particular format we move them into tool-version.test
and slightly unify (similarly to tool-name.test and tool-help-message.test).
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D87211
See https://lists.llvm.org/pipermail/llvm-dev/2020-July/143373.html
"[llvm-dev] Multiple documents in one test file" for some discussions.
`extract part filename` splits the input file into multiple parts separated by
regex `^(.|//)--- ` and extract the specified part to stdout or the
output file (if specified).
Use case A (organizing input of different formats (e.g. linker
script+assembly) in one file).
```
// RUN: extract lds %s -o %t.lds
// RUN: extract asm %s -o %t.s
// RUN: llvm-mc %t.s -o %t.o
// RUN: ld.lld -T %t.lds %t.o -o %t
This is sometimes better than the %S/Inputs/ approach because the user
can see the auxiliary files immediately and don't have to open another file.
```
Use case B (for utilities which don't have built-in input splitting
feature):
```
// RUN: extract case1 %s | llc | FileCheck %s --check-prefix=CASE1
// RUN: extract case2 %s | llc | FileCheck %s --check-prefix=CASE2
Combing tests prudently can improve readability.
This is sometimes better than having multiple test files.
```
Since this is a new utility, there is no git history concerns for
UpperCase variable names. I use lowerCase variable names like mlir/lld.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D83834
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
SHT_GROUP sections contain a reference to a symbol indicating their
"signature" symbol. The symbol table containing this symbol is referred
to by the group section's sh_link field. If llvm-objcopy is instructed
to remove the symbol table, it will emit an error.
This fixes https://bugs.llvm.org/show_bug.cgi?id=46153.
Reviewed By: jhenderson, Higuoxing
Differential Revision: https://reviews.llvm.org/D82274
Fangrui Song