[PATCH] D74791: Add a --shuffle-sections=seed option to lld

Wed Feb 19 17:19:58 PST 2020

MaskRay added a comment.

In D74791#1883878 <https://reviews.llvm.org/D74791#1883878>, @leonardchan wrote:

> Hi, I think this might be triggering the test failures seen on buildbot with:
>
>   Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.
>   FAIL: lld :: ELF/shuffle-sections.s (1760 of 2286)
>   ******************** TEST 'lld :: ELF/shuffle-sections.s' FAILED ********************
>   Script:
>   --
>   : 'RUN: at line 2';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/llvm-mc -filetype=obj -triple=x86_64 /b/s/w/ir/k/llvm-project/lld/test/ELF/shuffle-sections.s -o /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp.o
>   : 'RUN: at line 4';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/ld.lld /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp.o -o /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp.out
>   : 'RUN: at line 5';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/llvm-readelf -x .text /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp.out | /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/FileCheck /b/s/w/ir/k/llvm-project/lld/test/ELF/shuffle-sections.s
>   : 'RUN: at line 10';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/ld.lld --shuffle-sections=1 /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp.o -o /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp1.out
>   : 'RUN: at line 11';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/llvm-readelf -x .text /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp1.out | /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/FileCheck /b/s/w/ir/k/llvm-project/lld/test/ELF/shuffle-sections.s --check-prefix=SHUFFLE1
>   : 'RUN: at line 16';   echo "foo" > /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp_order.txt
>   : 'RUN: at line 17';   echo "_start " >> /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp_order.txt
>   : 'RUN: at line 19';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/ld.lld --symbol-ordering-file /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp_order.txt --shuffle-sections=2 /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp.o -o /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp2.out
>   : 'RUN: at line 20';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/llvm-readelf -x .text /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp2.out | /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/FileCheck /b/s/w/ir/k/llvm-project/lld/test/ELF/shuffle-sections.s --check-prefix=SHUFFLE2
>   : 'RUN: at line 24';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/ld.lld --symbol-ordering-file /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp_order.txt --shuffle-sections=3 /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp.o -o /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp3.out
>   : 'RUN: at line 25';   /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/llvm-readelf -x .text /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/tools/lld/test/ELF/Output/shuffle-sections.s.tmp3.out | /b/s/w/ir/k/recipe_cleanup/clangeEWbUm/llvm_build_dir/bin/FileCheck /b/s/w/ir/k/llvm-project/lld/test/ELF/shuffle-sections.s --check-prefix=SHUFFLE3
>   --
>   Exit Code: 1
>  
>   Command Output (stderr):
>   --
>   /b/s/w/ir/k/llvm-project/lld/test/ELF/shuffle-sections.s:13:18: error: SHUFFLE1-NEXT: expected string not found in input
>   # SHUFFLE1-NEXT: 01020403
>                    ^
>   <stdin>:2:1: note: scanning from here
>   0x00201120 01040203 ....
>   ^
>   <stdin>:2:12: note: possible intended match here
>   0x00201120 01040203 ....
>              ^
>  
>   --
>  
>   ********************
>   Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 
>  
>   Testing Time: 22.86s
>   ********************
>   Failing Tests (1):
>       lld :: ELF/shuffle-sections.s
>
>
> Could you send out a fix or revert this patch? Thanks.
>
> Our builder log: https://luci-milo.appspot.com/p/fuchsia/builders/ci/clang-linux-x64/b8887989700445045680

Fixed. I forgot that libstdc++, libc++, msvc and even different versions of these C++ standard libraries can have different random function implementations. We can't rely on any particular order.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D74791/new/

https://reviews.llvm.org/D74791