From: Richard Biener <rguenther@suse.de>
Date: Mon, 3 Aug 2020 13:05:37 +0000 (+0200)
Subject: lto/96385 - avoid unused global UNDEFs in debug objects
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b32c5d0b72fda2588b4e170e75a9c64e4bf266c7;p=gcc.git

lto/96385 - avoid unused global UNDEFs in debug objects

Unused global UNDEFs can have side-effects in some circumstances so
the following patch avoids them by treating them the same as other
to be discarded DEFs - make them local.

2020-08-03  Richard Biener  <rguenther@suse.de>

	PR lto/96385
libiberty/
	* simple-object-elf.c
	(simple_object_elf_copy_lto_debug_sections): Localize global
	UNDEFs and reuse the prevailing name.
---

diff --git a/libiberty/simple-object-elf.c b/libiberty/simple-object-elf.c
index c62d5bba551..7c9d492f6a4 100644
--- a/libiberty/simple-object-elf.c
+++ b/libiberty/simple-object-elf.c
@@ -1467,6 +1467,11 @@ simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj,
 		       && st_shndx < shnum
 		       && pfnret[st_shndx - 1] == -1)
 		discard = 1;
+	      /* We also need to remove global UNDEFs which can
+		 cause link fails later.  */
+	      else if (st_shndx == SHN_UNDEF
+		       && ELF_ST_BIND (*st_info) == STB_GLOBAL)
+		discard = 1;
 
 	      if (discard)
 		{