closes#154331
This PR addresses all minimum changes needed to compile LLVM and MLIR
with the c++23 standard.
It is a work in progress and to be reviewed for better methods of
handling the parts of the build broken by c++23.
This fixes "unused-local-typedef" warnings in 9324e6a7a5.
This adds an option `--remove-note=[name/]type` to selectively delete
notes in ELF files, where `type` is the numeric value of the note type
and `name` is the name of the originator. The name can be omitted, in
which case all notes of the specified type will be removed. For now,
only `SHT_NOTE` sections that are not associated with segments are
handled. The implementation can be extended later as needed.
RFC: https://discourse.llvm.org/t/rfc-llvm-objcopy-feature-for-editing-notes/83491
This adds an option `--remove-note=[name/]type` to selectively delete
notes in ELF files, where `type` is the numeric value of the note type
and `name` is the name of the originator. The name can be omitted, in
which case all notes of the specified type will be removed. For now,
only `SHT_NOTE` sections that are not associated with segments are
handled. The implementation can be extended later as needed.
RFC: https://discourse.llvm.org/t/rfc-llvm-objcopy-feature-for-editing-notes/83491
Otherwise, llvm-objcopy fails with use-after-free when built under
sanitizers. Simple repro: run the test
`ELF/remove-section-in-group.test` under asan. This is due to symbol
table references to empty section groups that must be removed.
Currently `llvm-objcopy/llvm-strip` in `--strip-debug` mode doesn't
remove such sections. This behavior can lead to incompatibilities with
GNU binutils (for examples ld.bfd before https://sourceware.org/PR20520
cannot process the object file contains empty .group section).
The ELF object that contains group section with `.debug_*` sections
inside can be obtained by `gcc -g3`.
Fix#97139
--compress-sections is similar to --compress-debug-sections but applies
to arbitrary sections.
* `--compress-sections <section>=none`: decompress sections
* `--compress-sections <section>=[zlib|zstd]`: compress sections with zlib/zstd
Like `--remove-section`, the pattern is by default a glob, but a regex
when --regex is specified.
For `--remove-section` like options, `!` prevents matches and is not
dependent on ordering (see `ELF/wildcard-syntax.test`). Since
`--compress-sections a=zlib --compress-sections a=none` naturally allows
overriding, having an order-independent `!` would be confusing.
Therefore, `!` is disallowed.
Sections within a segment are effectively immutable. Report an error for
an attempt to (de)compress them. `SHF_ALLOC` sections in a relocatable
file can be compressed, but linkers usually reject them.
Note: Before this patch, a compressed relocation section is recognized
as a `RelocationSectionBase` as well and `removeSections` `!ToRemove(*ToRelSec)`
may incorrectly interpret a `CompressedSections` as `RelocationSectionBase`,
leading to ubsan failure for the new test. Fix this by setting
`OriginalFlags` in CompressedSection::CompressedSection.
Link: https://discourse.llvm.org/t/rfc-compress-arbitrary-sections-with-ld-lld-compress-sections/71674
Pull Request: https://github.com/llvm/llvm-project/pull/85036
`TargetEndianness` is long and unwieldy. "Target" in the name is confusing. Rename it to "Endianness".
I cannot find noticeable out-of-tree users of `TargetEndianness`, but
keep `TargetEndianness` to make this patch safer. `TargetEndianness`
will be removed by a subsequent change.
(#79887) When the offset of a PT_INTERP segment equals the offset of a
PT_LOAD segment, we consider that the parent of the PT_LOAD segment is
the PT_INTERP segment. In `layoutSegments`, we place both segments to be
after the current `Offset`, ignoring the PT_LOAD alignment.
This scenario is possible with fixed section addresses, but doesn't
happen with default linker layouts (.interp precedes other sections and
is part of a PT_LOAD segment containing the ELF header and program
headers).
```
% cat a.s
.globl _start; _start: ret
.rodata; .byte 0
.tdata; .balign 4096; .byte 0
% clang -fuse-ld=lld a.s -o a -nostdlib -no-pie -z separate-loadable-segments -Wl,-Ttext=0x201000,--section-start=.interp=0x202000,--section-start=.rodata=0x202020,-z,nognustack
% llvm-objcopy a a2
% llvm-readelf -l a2 # incorrect offset(PT_LOAD)
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
PHDR 0x000040 0x0000000000200040 0x0000000000200040 0x0001c0 0x0001c0 R 0x8
INTERP 0x001001 0x0000000000202000 0x0000000000202000 0x00001c 0x00001c R 0x1
[Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]
LOAD 0x000000 0x0000000000200000 0x0000000000200000 0x000200 0x000200 R 0x1000
LOAD 0x001000 0x0000000000201000 0x0000000000201000 0x000001 0x000001 R E 0x1000
//// incorrect offset
LOAD 0x001001 0x0000000000202000 0x0000000000202000 0x000021 0x000021 R 0x1000
LOAD 0x002000 0x0000000000203000 0x0000000000203000 0x000001 0x001000 RW 0x1000
TLS 0x002000 0x0000000000203000 0x0000000000203000 0x000001 0x000001 R 0x1000
GNU_RELRO 0x002000 0x0000000000203000 0x0000000000203000 0x000001 0x001000 R 0x1000
```
The same issue occurs for PT_TLS/PT_GNU_RELRO if we PT_TLS's alignment
is smaller and we place the PT_LOAD after PT_TLS/PT_GNU_RELRO segments
(not linker default, but possible with a `PHDRS` linker script command).
Fix#79887: when two segments have the same offset, order the one with a
larger alignment first. In the previous case, the PT_LOAD segment will
go before the PT_INTERP segment. In case of equal alignments, it doesn't
matter which segment is treated as the parent segment.
In the change that added `--gap-fill`, the condition to choose the
sections to write in `BinaryWriter::write()` did not exclude zero-size
sections. However, zero-size sections did not have correct offsets
assigned in `BinaryWriter::finalize()`. The result is either a failed
assertion, or memory corruption due to writing to the buffer beyond its
size.
To fix this, exclude zero-size sections from writing. Also, add a zero-size
section to the test, which would trigger the problem.
`--gap-fill <value>` fills the gaps between sections with a specified
8-bit value, instead of zero.
`--pad-to <address>` pads the output binary up to the specified load
address, using the 8-bit value from `--gap-fill` or zero.
These options are only supported for ELF input and binary output.
Note that llvm::support::endianness has been renamed to
llvm::endianness while becoming an enum class as opposed to an
enum. This patch replaces support::{big,little,native} with
llvm::endianness::{big,little,native}.
llvm-objcopy should not insert padding before a section if its
physical addresses is not aligned to section's alignment. This
behavior will match GNU objcopy and is important for embedded images
where the physical address is used to store the initial data image.
The loader typically will copy this image using a start symbol
created by the linker. If llvm-objcopy inserts padding before such a
section, the symbol address will not match the location in the image.
This commit refines the change in https://reviews.llvm.org/D128961
which intended to align sections which type changed from NOBITS and
their offset may not be aligned. However, it affected all sections.
Fix https://github.com/llvm/llvm-project/issues/62636
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D150276
This reverts commit eb1442d0f73c76cfb5051d133f858fe760d189cf.
The test tools/llvm-objcopy/ELF/binary-paddr.test fails on
ppc64be-clang-test-suite:
https://lab.llvm.org/buildbot#builders/231/builds/13120
Reverting at author's request.
llvm-objcopy should not insert padding before a section if its
physical addresses is not aligned to section's alignment. This
behavior will match GNU objcopy and is important for embedded images
where the physical address is used to store the initial data image.
The loader typically will copy this image using a start symbol
created by the linker. If llvm-objcopy inserts padding before such a
section, the symbol address will not match the location in the image.
This commit refines the change in https://reviews.llvm.org/D128961
which intended to align sections which type changed from NOBITS and
their offset may not be aligned. However, it affected all sections.
Fix https://github.com/llvm/llvm-project/issues/62636
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D150276
This change to llvm-objcopy preserves the ELF section sh_link to .symtab
so long as none of the symbol table indices have been changed.
Previously, any invocation of llvm-objcopy including a "no-op" would
clear any section sh_link to .symtab.
Differential Revision: https://reviews.llvm.org/D150859
The gABI prohibits multiple SH_SYMTAB sections. As a result,
llvm-objcopy was crashing in SymbolTableSection::removeSymbols(). This
patch fixes the issue by emitting an error if multiple SH_SYMTAB
sections are encountered when building an ELF object.
Fixes: https://github.com/llvm/llvm-project/issues/60448
Differential Revision: https://reviews.llvm.org/D143508
This used %zu to print a uint64_t type. z is for size_t so on 32 bit
we tried to treat it as a 32 bit number.
Use PRIu64 instead to print as 64 bit everywhere.
When zlib is disabled at build time, the diagnostic `LLVM was not compiled with
LLVM_ENABLE_ZLIB: cannot decompress` for --decompress-debug-sections may be
inaccurate: if zstd is enabled, we should still support zstd decompression.
It's not useful to test zlib and zstd. Just remove the diagnostic and add a new
one before `compression::decompress`.
This fixes compress-debug-sections-zstd.test
Reviewed By: mariusz-sikora-at-amd, jhenderson, phosek
Differential Revision: https://reviews.llvm.org/D135744
For an ELFCLASS32 object, a compressed section due to --compress-debug-sections={zlib,zstd} has a
tail padding of 12 zero bytes. zlib happily allows this while zstd is rigid and
reports `error: '{{.*}}': failed to decompress section '.debug_foo': Src size is incorrect`.
Cole Kissane reported the problem.
Reviewed By: jhenderson, phosek
Differential Revision: https://reviews.llvm.org/D134385
"Z" was so named when we had both gABI ELFCOMPRESS_ZLIB and the legacy .zdebug support.
Now we have just one zlib format, we should use the more descriptive name.
This reverts commit 19dc3cff0f771bb8933136ef68e782553e920d04.
This reverts commit 5b19a1f8e88da9ec92b995bfee90043795c2c252.
This reverts commit 9397648ac8ad192f7e6e6a8e6894c27bf7e024e9.
This reverts commit 10842b44759f987777b08e7714ef77da2526473a.
Breaks the GCC build, as reported here:
https://reviews.llvm.org/D130506#3776415
This reverts commit c26dc2904b95b3685d883e760e84046ea6c33d7f.
The new Zstd dispatch has an ongoing design discussion related to https://reviews.llvm.org/D130516#3688123 .
Revert for now before it is resolved.
It's more natural to use uint8_t * (std::byte needs C++17 and llvm has
too much uint8_t *) and most callers use uint8_t * instead of char *.
The functions are recently moved into `llvm::compression::zlib::`, so
downstream projects need to make adaption anyway.
* Refactor compression namespaces across the project, making way for a possible
introduction of alternatives to zlib compression.
Changes are as follows:
* Relocate the `llvm::zlib` namespace to `llvm::compression::zlib`.
Reviewed By: MaskRay, leonardchan, phosek
Differential Revision: https://reviews.llvm.org/D128953
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
Remove Expected<CompressedSection> factory functions in favor of constructors
now that zlib::compress returns void (D121512).
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D121644
