[binutils-gdb] Create a PLT entry for R_386_PC32 in non-code sections

[H.J.Lu <hjl at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=4b627c18440f51077f8fd4c18adaa3919c3a373e

commit 4b627c18440f51077f8fd4c18adaa3919c3a373e
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Sep 30 08:32:45 2015 -0700

    Create a PLT entry for R_386_PC32 in non-code sections
    
    Since something like ".long foo - ." may be used as pointer, we make
    sure that PLT is used if foo is a function defined in a shared library.
    
    bfd/
    
    	PR ld/19031
    	* elf32-i386.c (elf_i386_check_relocs): Set
    	pointer_equality_needed for R_386_PC32 reloc in non-code
    	sections.
    
    ld/testsuite/
    
    	PR ld/19031
    	* ld-i386/i386.exp: Run PR ld/19031 test.
    	* ld/testsuite/ld-i386/pr19031.out: New file.
    	* ld/testsuite/ld-i386/pr19031a.c: Likewise.
    	* ld/testsuite/ld-i386/pr19031b.S: Likewise.
    	* ld/testsuite/ld-i386/pr19031c.c: Likewise.

Diff:
---
 bfd/ChangeLog                    |  7 +++++++
 bfd/elf32-i386.c                 | 10 +++++++++-
 ld/testsuite/ChangeLog           |  9 +++++++++
 ld/testsuite/ld-i386/i386.exp    | 16 ++++++++++++++++
 ld/testsuite/ld-i386/pr19031.out |  1 +
 ld/testsuite/ld-i386/pr19031a.c  |  4 ++++
 ld/testsuite/ld-i386/pr19031b.S  | 23 +++++++++++++++++++++++
 ld/testsuite/ld-i386/pr19031c.c  | 14 ++++++++++++++
 8 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index a218d44..3610948 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,5 +1,12 @@
 2015-09-30  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR ld/19031
+	* elf32-i386.c (elf_i386_check_relocs): Set
+	pointer_equality_needed for R_386_PC32 reloc in non-code
+	sections.
+
+2015-09-30  H.J. Lu  <hongjiu.lu@intel.com>
+
 	PR ld/19013
 	* elflink.c (_bfd_elf_merge_sections): Only merge input bfds
 	that have the compatible ELF machine code with the output bfd.
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 9390450..0a06191 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -1772,7 +1772,15 @@ elf_i386_check_relocs (bfd *abfd,
 	      /* We may need a .plt entry if the function this reloc
 		 refers to is in a shared lib.  */
 	      h->plt.refcount += 1;
-	      if (r_type != R_386_PC32)
+	      if (r_type == R_386_PC32)
+		{
+		  /* Since something like ".long foo - ." may be used
+		     as pointer, make sure that PLT is used if foo is
+		     a function defined in a shared library.  */
+		  if ((sec->flags & SEC_CODE) == 0)
+		    h->pointer_equality_needed = 1;
+		}
+	      else
 		{
 		  h->pointer_equality_needed = 1;
 		  /* R_386_32 can be resolved at run-time.  */
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index 7f1b7ac..9c77301 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,5 +1,14 @@
 2015-09-30  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR ld/19031
+	* ld-i386/i386.exp: Run PR ld/19031 test.
+	* ld/testsuite/ld-i386/pr19031.out: New file.
+	* ld/testsuite/ld-i386/pr19031a.c: Likewise.
+	* ld/testsuite/ld-i386/pr19031b.S: Likewise.
+	* ld/testsuite/ld-i386/pr19031c.c: Likewise.
+
+2015-09-30  H.J. Lu  <hongjiu.lu@intel.com>
+
 	PR ld/19013
 	* ld-x86-64/pr19013-nacl.d: New file.
 	* ld-x86-64/pr19013-x32.d: Likewise.
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index 6213dbe..8cddfce 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -490,6 +490,14 @@ if { [isnative]
 	    {{readelf {-Wrd} pr18900b.rd}} \
 	    "pr18900b" \
 	] \
+	[list \
+	    "Build pr19031.so" \
+	    "-shared" \
+	    "-fPIC" \
+	    { pr19031a.c } \
+	    "" \
+	    "pr19031.so" \
+	] \
     ]
 
     run_ld_link_exec_tests [] [list \
@@ -552,6 +560,14 @@ if { [isnative]
 	    "pr18900" \
 	    "pr18900.out" \
 	] \
+	[list \
+	    "Run pr19031" \
+	    "tmpdir/pr19031.so" \
+	    "" \
+	    { pr19031b.S pr19031c.c } \
+	    "pr19031" \
+	    "pr19031.out" \
+	] \
     ]
 }
 
diff --git a/ld/testsuite/ld-i386/pr19031.out b/ld/testsuite/ld-i386/pr19031.out
new file mode 100644
index 0000000..d86bac9
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr19031.out
@@ -0,0 +1 @@
+OK
diff --git a/ld/testsuite/ld-i386/pr19031a.c b/ld/testsuite/ld-i386/pr19031a.c
new file mode 100644
index 0000000..fa34d37
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr19031a.c
@@ -0,0 +1,4 @@
+void
+f (void)
+{
+}
diff --git a/ld/testsuite/ld-i386/pr19031b.S b/ld/testsuite/ld-i386/pr19031b.S
new file mode 100644
index 0000000..3249652
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr19031b.S
@@ -0,0 +1,23 @@
+	.text
+	.globl g
+	.type g, @function
+g:
+        calll .Lfoo
+.Lfoo:
+        popl %eax
+.Lbar:
+        addl $_GLOBAL_OFFSET_TABLE_+(.Lbar-.Lfoo), %eax
+	movl f@GOT(%eax), %eax
+	ret
+
+	.globl h
+	.type h, @function
+h:
+        leal zed, %eax
+        movl zed, %ebx
+        addl %ebx, %eax
+	ret
+
+	.data
+zed:
+        .long f - .
diff --git a/ld/testsuite/ld-i386/pr19031c.c b/ld/testsuite/ld-i386/pr19031c.c
new file mode 100644
index 0000000..60eccaf
--- /dev/null
+++ b/ld/testsuite/ld-i386/pr19031c.c
@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+extern void *h (void);
+extern void *g (void);
+
+int
+main (void)
+{
+
+  if (h () == g ())
+    printf ("OK\n");
+
+  return 0;
+}