[PATCH] D30188: [ELF] - Do not segfault when using --gc-sections with linker script

[Rafael Avila de Espindola via llvm-commits]

> Index: test/ELF/linkerscript/sections-gc.s
> ===================================================================
> --- test/ELF/linkerscript/sections-gc.s
> +++ test/ELF/linkerscript/sections-gc.s
> @@ -0,0 +1,19 @@
> +# REQUIRES: x86
> +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
> +# RUN: echo "SECTIONS { .text : { *(.text*) } }" > %t.script
> +# RUN: ld.lld %t --gc-sections --script %t.script -o %t1
> +# RUN: llvm-objdump -section-headers %t1 | FileCheck %s
> +
> +# CHECK:      Sections:
> +# CHECK-NEXT:  Name      Size
> +# CHECK:       .text     00000001
> +
> +.section .text.foo, "a"
> +.global foo
> +foo:
> +  nop
> +
> +.section .text.bar
> +.global bar
> +bar:
> +  nop

I am not sure I fully understand what is going on with this
testcase. Why do you need text.bar to be non-SHF_ALLOC? You just need a
section to not be live, right?

This testcase will produce an error without --gc-sections. It seems like
a small bug for --gc-sections to make it valid and we should not depend
on that.

Please change the test to

.section .text.foo, "ax"
.global _start
_start:
  nop

.section .text.bar, "ax"
.global bar
bar:
  nop


LGTM with that.

Cheers,
Rafael