f1ca2a0967
--compress-sections <section-glib>=[none|zlib|zstd] is similar to --compress-debug-sections but applies to broader sections without the SHF_ALLOC flag. lld will report an error if a SHF_ALLOC section is matched. An interesting use case is to compress `.strtab`/`.symtab`, which consume a significant portion of the file size (15.1% for a release build of Clang). An older revision is available at https://reviews.llvm.org/D154641 . This patch focuses on non-allocated sections for safety. Moving `maybeCompress` as D154641 does not handle STT_SECTION symbols for `-r --compress-debug-sections=zlib` (see `relocatable-section-symbol.s` from #66804). Since different output sections may use different compression algorithms, we need CompressedData::type to generalize config->compressDebugSections. GNU ld feature request: https://sourceware.org/bugzilla/show_bug.cgi?id=27452 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/84855
63 lines
1.6 KiB
ArmAsm
63 lines
1.6 KiB
ArmAsm
# REQUIRES: x86, zlib
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# RUN: rm -rf %t && split-file %s %t && cd %t
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# RUN: llvm-mc -filetype=obj -triple=x86_64 a.s -o a.o
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# RUN: ld.lld -T a.lds a.o --compress-sections nonalloc=zlib --compress-sections str=zlib -o out
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# RUN: llvm-readelf -SsXz -p str out | FileCheck %s
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# CHECK: Name Type Address Off Size ES Flg Lk Inf Al
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# CHECK: nonalloc PROGBITS 0000000000000000 [[#%x,]] [[#%x,]] 00 C 0 0 1
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# CHECK-NEXT: str PROGBITS 0000000000000000 [[#%x,]] [[#%x,]] 01 MSC 0 0 1
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# CHECK: 0000000000000000 0 NOTYPE GLOBAL DEFAULT [[#]] (nonalloc) nonalloc_start
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# CHECK: 0000000000000023 0 NOTYPE GLOBAL DEFAULT [[#]] (nonalloc) nonalloc_end
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# CHECK: String dump of section 'str':
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# CHECK-NEXT: [ 0] AAA
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# CHECK-NEXT: [ 4] BBB
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## TODO The uncompressed size of 'nonalloc' is dependent on linker script
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## commands, which is not handled. We should report an error.
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# RUN: ld.lld -T b.lds a.o --compress-sections nonalloc=zlib
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#--- a.s
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.globl _start
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_start:
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ret
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.section nonalloc0,""
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.balign 8
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.quad .text
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.quad .text
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.section nonalloc1,""
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.balign 8
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.quad 42
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.section str,"MS",@progbits,1
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.asciz "AAA"
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.asciz "BBB"
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#--- a.lds
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SECTIONS {
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.text : { *(.text) }
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c = SIZEOF(.text);
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b = c+1;
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a = b+1;
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nonalloc : {
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nonalloc_start = .;
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## In general, using data commands is error-prone. This case is correct, though.
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*(nonalloc*) QUAD(SIZEOF(.text))
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. += a;
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nonalloc_end = .;
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}
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str : { *(str) }
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}
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#--- b.lds
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SECTIONS {
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nonalloc : { *(nonalloc*) . += a; }
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.text : { *(.text) }
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a = b+1;
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b = c+1;
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c = SIZEOF(.text);
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}
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