diff --git a/lld/ELF/MarkLive.cpp b/lld/ELF/MarkLive.cpp --- a/lld/ELF/MarkLive.cpp +++ b/lld/ELF/MarkLive.cpp @@ -261,6 +261,10 @@ scanEhFrameSection(*eh, eh->template rels()); } + if (sec->flags & SHF_GNU_RETAIN) { + enqueue(sec, 0); + continue; + } if (sec->flags & SHF_LINK_ORDER) continue; diff --git a/lld/test/ELF/gc-sections-retain.s b/lld/test/ELF/gc-sections-retain.s new file mode 100644 --- /dev/null +++ b/lld/test/ELF/gc-sections-retain.s @@ -0,0 +1,44 @@ +# REQUIRES: x86 +## SHF_GNU_RETAIN is a generic feature defined in the OS specific range. The +## flag marks a section as a GC root. + +# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o +# RUN: ld.lld --gc-sections --print-gc-sections %t.o -o %t | count 0 +# RUN: llvm-readobj -hS %t | FileCheck %s +# RUN: ld.lld -r -e _start --gc-sections --print-gc-sections %t.o -o %t.ro | count 0 +# RUN: llvm-readobj -hS %t.ro | FileCheck %s + +## SHF_GNU_RETAIN has no significance in executables/shared objects. Multiple +## OSABI values can benefit from this flag. Test that we don't change EI_OSABI, +## even for relocatable output. +# CHECK: OS/ABI: SystemV (0x0) + +# CHECK: Name: .retain +# CHECK-NEXT: Type: SHT_PROGBITS +# CHECK-NEXT: Flags [ +# CHECK-NEXT: SHF_ALLOC +# CHECK-NEXT: SHF_GNU_RETAIN +# CHECK-NEXT: ] + +# RUN: llvm-mc -filetype=obj -triple=x86_64 --defsym NONALLOC=1 %s -o %t1.o +# RUN: not ld.lld --gc-sections %t1.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=ERR + +# ERR: error: {{.*}}.o:(.nonalloc): sh_link points to discarded section {{.*}}.o:(.discard) + +.global _start +_start: + +.section .retain,"aR",@progbits +.quad .foo + +.section .foo,"a",@progbits +.quad 0 + +.ifdef NONALLOC +.section .discard,"a",@progbits + +## With SHF_GNU_RETAIN, .nonalloc is retained while its linked-to section +## .discard is discarded, so there will be an error. +.section .nonalloc,"oR",@progbits,.discard +.quad .text +.endif