[lld] r355894 - Fix test to unconditionally create a GNU-format archive.

[Eli Friedman via llvm-commits]

I spent a bit of time looking at this.  By default, llvm-ar will automatically generate a symbol table… which suppresses the lld error because lld never looks at unneeded object files in an archive with a symbol table.  However, there’s an exception: if the host is not Darwin, and the archive contains no object files, llvm-ar skips generating a symbol table even if one is requested.

Maybe it makes sense to change the behavior of llvm-ar so it’s more consistent… I’m not sure what the history is behind making the symbol table behavior depend on the archive format.

On a sort of related note, maybe we want to change lld so it doesn’t generate the “not an ELF file” error for archives which don’t have a symbol table?  That would be more consistent with the behavior of archives with a symbol table.

-Eli

From: Rui Ueyama <ruiu at google.com>
Sent: Wednesday, March 13, 2019 4:23 PM
To: Eli Friedman <efriedma at quicinc.com>
Cc: llvm-commits <llvm-commits at lists.llvm.org>
Subject: [EXT] Re: [lld] r355894 - Fix test to unconditionally create a GNU-format archive.

lld uses LLVM's libObject to read archive files, and I believe the library supports all variants of archive files, so it is odd that lld can't read some archive variant. Something is not right...

On Mon, Mar 11, 2019 at 7:18 PM Eli Friedman via llvm-commits <llvm-commits at lists.llvm.org<mailto:llvm-commits at lists.llvm.org>> wrote:
Author: efriedma
Date: Mon Mar 11 19:20:01 2019
New Revision: 355894

URL: http://llvm.org/viewvc/llvm-project?rev=355894&view=rev
Log:
Fix test to unconditionally create a GNU-format archive.

On Darwin targets, llvm-ar creates a Darwin format archive by default,
which ld.lld can't read, so it was printing an unexpected error.


Modified:
    lld/trunk/test/ELF/invalid/invalid-elf.test

Modified: lld/trunk/test/ELF/invalid/invalid-elf.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/invalid/invalid-elf.test?rev=355894&r1=355893&r2=355894&view=diff
==============================================================================
--- lld/trunk/test/ELF/invalid/invalid-elf.test (original)
+++ lld/trunk/test/ELF/invalid/invalid-elf.test Mon Mar 11 19:20:01 2019
@@ -2,7 +2,7 @@
 # RUN: rm -rf %t && mkdir -p %t
 # RUN: llvm-mc %s -o %t/simple.o -filetype=obj -triple x86_64-pc-linux
 # RUN: echo > %t/empty.o
-# RUN: llvm-ar cr %t/not-elf.a %t/empty.o
+# RUN: llvm-ar --format=gnu cr %t/not-elf.a %t/empty.o

 # RUN: not ld.lld %t/simple.o %t/not-elf.a -o %t2 2>&1 | \
 # RUN:   FileCheck --check-prefix=NOT-ELF %s


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