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--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
39 lines
1.3 KiB
ArmAsm
39 lines
1.3 KiB
ArmAsm
## Disallow (de)compression for sections within a segment as they are
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## effectively immutable.
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# RUN: rm -rf %t && mkdir %t && cd %t
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# RUN: yaml2obj %s -o a
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# RUN: not llvm-objcopy a /dev/null --compress-sections .text=zlib 2>&1 | FileCheck %s --implicit-check-not=error:
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# CHECK: error: 'a': section '.text' within a segment cannot be (de)compressed
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# RUN: not llvm-objcopy a /dev/null --compress-sections foo=none 2>&1 | FileCheck %s --check-prefix=CHECK2 --implicit-check-not=error:
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# CHECK2: error: 'a': section 'foo' within a segment cannot be (de)compressed
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## There is an error even if 'foo' is already compressed with zlib.
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# RUN: not llvm-objcopy a /dev/null --compress-sections foo=zlib 2>&1 | FileCheck %s --check-prefix=CHECK3 --implicit-check-not=error:
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# CHECK3: error: 'a': section 'foo' within a segment cannot be (de)compressed
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--- !ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_EXEC
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Machine: EM_X86_64
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ProgramHeaders:
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- Type: PT_LOAD
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FirstSec: .text
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LastSec: foo
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Align: 0x1000
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Offset: 0x1000
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Sections:
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- Name: .text
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Type: SHT_PROGBITS
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Offset: 0x1000
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Content: C3
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- Name: foo
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Type: SHT_PROGBITS
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Flags: [ SHF_COMPRESSED ]
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Content: 010000000000000040000000000000000100000000000000789cd36280002d3269002f800151
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