ld/elf: Ignore section symbols when matching linkonce with comdat

When deciding if a single member comdat group section in file FOO should
be discarded by a linkonce section in file BAR, we check if 2 sections
define the same set of local and global symbols.  When only one of the
files doesn't contain the unused section symbols in the symbol table,
such as object files generated by clang or GNU assembler with

commit d1bcae833b32f1408485ce69f844dcd7ded093a8
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Jan 7 06:42:00 2021 -0800

    ELF: Don't generate unused section symbols

the check will fail since one file has the extra unused section symbols.
We should ignore both undefined and section symbols in the symbol table
when making such a decision.

bfd/

	PR ld/27193
	* elflink.c (elf_create_symbuf): Also ignore section symbols.

ld/

	PR ld/27193
	* testsuite/ld-i386/i386.exp: Run PR ld/27193 test.
	* testsuite/ld-i386/pr27193.dd: New file.
	* testsuite/ld-i386/pr27193a.o.bz2: Likewise.
	* testsuite/ld-i386/pr27193b.s: Likewise.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index dbb240ad612933016f50c612bd048b7c92c0f9ad..b947c5172021cb51a43ba04a56f376f97cc7e5b4 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,8 @@
+2021-01-17  H.J. Lu  <hongjiu.lu@intel.com>
+
+       PR ld/27193
+       * elflink.c (elf_create_symbuf): Also ignore section symbols.
+
 2021-01-16  H.J. Lu  <hongjiu.lu@intel.com>
 
        PR ld/23169

diff --git a/bfd/elflink.c b/bfd/elflink.c
index 8794864f54cb50fa79b970a62e871fdd4511af81..59a6080f37a302330bd10fe72ad6d53b85fcc344 100644 (file)
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -8126,8 +8126,12 @@ elf_create_symbuf (size_t symcount, Elf_Internal_Sym *isymbuf)
   if (indbuf == NULL)
     return NULL;
 
+  /* NB: When checking if 2 sections define the same set of local and
+     global symbols, ignore both undefined and section symbols in the
+     symbol table.  */
   for (ind = indbuf, i = 0; i < symcount; i++)
-    if (isymbuf[i].st_shndx != SHN_UNDEF)
+    if (isymbuf[i].st_shndx != SHN_UNDEF
+       && ELF_ST_TYPE (isymbuf[i].st_info) != STT_SECTION)
       *ind++ = &isymbuf[i];
   indbufend = ind;
 

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 6b602d603412b4e4189af0a29807ca14e4fe09d8..92fa8a4e1c36ef2df9b60a56a71358de979f7ed3 100644 (file)
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,11 @@
+2021-01-17  H.J. Lu  <hongjiu.lu@intel.com>
+
+       PR ld/27193
+       * testsuite/ld-i386/i386.exp: Run PR ld/27193 test.
+       * testsuite/ld-i386/pr27193.dd: New file.
+       * testsuite/ld-i386/pr27193a.o.bz2: Likewise.
+       * testsuite/ld-i386/pr27193b.s: Likewise.
+
 2021-01-16  H.J. Lu  <hongjiu.lu@intel.com>
 
        PR binutils/23460

diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index f3e62a4151e6c8d83205612bd8f3f7ffcdd93b13..0be6b861daba79092e12e4f60af643f01ff5c1c3 100644 (file)
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -245,6 +245,11 @@ set i386tests {
      "-melf_i386 -shared -Bsymbolic -z notext" ""
      "--32 -mx86-used-note=yes"
      { pr19827a.S }  {{readelf {-rW} pr19827.rd}} "pr19827.so"}
+    {"Build pr27193.so"
+     "-melf_i386 -shared" ""
+     "--32"
+     { pr27193a.o.bz2 pr27193b.s }
+     {{objdump {-dw} pr27193.dd}} "pr27193.so"}
 }
 
 proc iamcu_tests {} {

diff --git a/ld/testsuite/ld-i386/pr27193.dd b/ld/testsuite/ld-i386/pr27193.dd
new file mode 100644 (file)
index 0000000..7d1e799
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr27193.dd
@@ -0,0 +1,5 @@
+#...
+0+[a-f0-9]+ <__x86.get_pc_thunk.bx>:
+ +[a-f0-9]+:   8b 1c 24                mov    \(%esp\),%ebx
+ +[a-f0-9]+:   c3                      ret    
+#pass

diff --git a/ld/testsuite/ld-i386/pr27193a.o.bz2 b/ld/testsuite/ld-i386/pr27193a.o.bz2
new file mode 100644 (file)
index 0000000..365899d
Binary files /dev/null and b/ld/testsuite/ld-i386/pr27193a.o.bz2 differ

diff --git a/ld/testsuite/ld-i386/pr27193b.s b/ld/testsuite/ld-i386/pr27193b.s
new file mode 100644 (file)
index 0000000..9b27a6f
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr27193b.s
@@ -0,0 +1,8 @@
+        .section .text.__x86.get_pc_thunk.bx,"axG",%progbits,__x86.get_pc_thunk.bx,comdat
+        .globl  __x86.get_pc_thunk.bx
+        .hidden __x86.get_pc_thunk.bx
+        .type   __x86.get_pc_thunk.bx, %function
+       .p2align 4
+__x86.get_pc_thunk.bx:
+       mov     (%esp),%ebx
+       ret