6d2d3bd0a6
Change the default to facilitate GC for metadata section usage, so that they don't need SHF_LINK_ORDER or SHF_GROUP just to drop the unhelpful rule (if they want to be unconditionally retained, use SHF_GNU_RETAIN (`__attribute__((retain))`) or linker script `KEEP`). The dropped SHF_GROUP special case makes the behavior of -z start-stop-gc and -z nostart-stop-gc closer to GNU ld>=2.37 (https://sourceware.org/PR27451). However, we default to -z start-stop-gc (which actually matches more closely to GNU ld before 2015-10 https://sourceware.org/PR19167), which is different from modern GNU ld (which has the unhelpful rule to work around glibc). As a compensation, we special case `__libc_` sections as a workaround for glibc<2.34 (https://sourceware.org/PR27492). Since -z start-stop-gc as the default actually matches the traditional GNU ld behavior, there isn't much to be aware of. There was a systemd usage which has been fixed by https://github.com/systemd/systemd/pull/19144
32 lines
869 B
ArmAsm
32 lines
869 B
ArmAsm
# REQUIRES: x86
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# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
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# RUN: echo "SECTIONS { \
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# RUN: used_in_reloc : { *(used_in_reloc) } \
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# RUN: used_in_script : { *(used_in_script) } \
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# RUN: .text : { *(.text) } \
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# RUN: }" > %t.script
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# RUN: ld.lld -T %t.script -o %t.so %t.o --gc-sections -z nostart-stop-gc
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# RUN: llvm-objdump -h %t.so | FileCheck %s
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# CHECK: Idx Name Size VMA Type
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# CHECK-NEXT: 0
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# CHECK-NEXT: used_in_reloc
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# CHECK-NEXT: .text
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# CHECK-NEXT: .comment
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# CHECK-NEXT: .symtab
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# CHECK-NEXT: .shstrtab
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# CHECK-NEXT: .strtab
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.global _start
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_start:
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.quad __start_used_in_reloc
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.section unused,"a"
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.quad 0
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.section used_in_script,"a"
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.quad __start_used_in_script
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.section used_in_reloc,"a"
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.quad 0
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