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PATCH: PR ld/13817: Broken IFUNC support

From: "H.J. Lu" <hongjiu dot lu at intel dot com>
To: binutils at sourceware dot org
Date: Fri, 9 Mar 2012 08:32:27 -0800
Subject: PATCH: PR ld/13817: Broken IFUNC support
Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Hi,

We have to use real function, not PLT entry for non-GOT reference to
locally defined IFUNC symbols, at least on i386, since the PLT slot
assumes that %ebx of the caller points to the _GLOBAL_OFFSET_TABLE_
symbol of the library containing the PLT slot.  I checked in this
patch to revert:

http://sourceware.org/ml/binutils/2011-10/msg00203.html

Although x86-64 doesn't have this problem. I reverted both i386 and
x86-64 changes to keep i386 consistent with x86-64 as much as possible.


H.J.
---
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 2140240..66a7339 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2012-03-09  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/13817
+	* bfd/elf32-i386.c (elf_i386_relocate_section): Restore
+	R_386_IRELATIVE.
+
+	* * elf64-x86-64.c (elf_x86_64_relocate_section): Restore
+	R_X86_64_IRELATIVE.
+
 2012-03-08  Tristan Gingold  <gingold@adacore.com>
 
 	* vms-lib.c (_bfd_vms_lib_write_archive_contents): Set maximum
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index d187305..01c0669 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -3257,7 +3257,6 @@ elf_i386_relocate_section (bfd *output_bfd,
 		  bfd_byte *loc;
 		  asection *sreloc;
 		  bfd_vma offset;
-		  bfd_boolean relocate;
 
 		  /* Need a dynamic relocation to get the real function
 		     adddress.  */
@@ -3278,14 +3277,15 @@ elf_i386_relocate_section (bfd *output_bfd,
 		      || info->executable)
 		    {
 		      /* This symbol is resolved locally.  */
-		      outrel.r_info = ELF32_R_INFO (0, R_386_RELATIVE);
-		      relocate = TRUE;
+		      outrel.r_info = ELF32_R_INFO (0, R_386_IRELATIVE);
+		      bfd_put_32 (output_bfd,
+				  (h->root.u.def.value
+				   + h->root.u.def.section->output_section->vma
+				   + h->root.u.def.section->output_offset),
+				  contents + offset);
 		    }
 		  else
-		    {
-		      outrel.r_info = ELF32_R_INFO (h->dynindx, r_type);
-		      relocate = FALSE;
-		    }
+		    outrel.r_info = ELF32_R_INFO (h->dynindx, r_type);
 
 		  sreloc = htab->elf.irelifunc;
 		  loc = sreloc->contents;
@@ -3298,8 +3298,7 @@ elf_i386_relocate_section (bfd *output_bfd,
 		     we need to include the symbol value so that it
 		     becomes an addend for the dynamic reloc.  For an
 		     internal symbol, we have updated addend.  */
-		  if (! relocate)
-		    continue;
+		  continue;
 		}
 	      /* FALLTHROUGH */
 	    case R_386_PC32:
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 81ed866..47f1295 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -3156,7 +3156,6 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 		{
 		  Elf_Internal_Rela outrel;
 		  asection *sreloc;
-		  bfd_boolean relocate;
 
 		  /* Need a dynamic relocation to get the real function
 		     address.  */
@@ -3176,15 +3175,15 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 		      || info->executable)
 		    {
 		      /* This symbol is resolved locally.  */
-		      outrel.r_info = htab->r_info (0, R_X86_64_RELATIVE);
-		      outrel.r_addend = relocation;
-		      relocate = TRUE;
+		      outrel.r_info = htab->r_info (0, R_X86_64_IRELATIVE);
+		      outrel.r_addend = (h->root.u.def.value
+					 + h->root.u.def.section->output_section->vma
+					 + h->root.u.def.section->output_offset);
 		    }
 		  else
 		    {
 		      outrel.r_info = htab->r_info (h->dynindx, r_type);
 		      outrel.r_addend = 0;
-		      relocate = FALSE;
 		    }
 
 		  sreloc = htab->elf.irelifunc;
@@ -3195,8 +3194,7 @@ elf_x86_64_relocate_section (bfd *output_bfd,
 		     we need to include the symbol value so that it
 		     becomes an addend for the dynamic reloc.  For an
 		     internal symbol, we have updated addend.  */
-		  if (! relocate)
-		    continue;
+		  continue;
 		}
 	      /* FALLTHROUGH */
 	    case R_X86_64_PC32:
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index b49cce5..1e3c5c1 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2012-03-09  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/13817
+	* ld-i386/pr13302.d: Updated.
+	* ld-x86-64/pr13082-5b.d: Likewise.
+	* ld-x86-64/pr13082-6a.d: Likewise.
+	* ld-x86-64/pr13082-6b.d: Likewise.
+
 2012-03-06  Alan Modra  <amodra@gmail.com>
 
 	PR ld/13683
diff --git a/ld/testsuite/ld-i386/pr13302.d b/ld/testsuite/ld-i386/pr13302.d
index 3d85d08..35c09ae 100644
--- a/ld/testsuite/ld-i386/pr13302.d
+++ b/ld/testsuite/ld-i386/pr13302.d
@@ -5,7 +5,7 @@
 
 Relocation section '.rel.dyn' at offset 0x[0-9a-f]+ contains 1 entries:
  Offset     Info    Type                Sym. Value  Symbol's Name
-[0-9a-f]+ +[0-9a-f]+ +R_386_RELATIVE +
+[0-9a-f]+ +[0-9a-f]+ +R_386_IRELATIVE +
 
 Relocation section '.rel.plt' at offset 0x[0-9a-f]+ contains 1 entries:
  Offset     Info    Type                Sym. Value  Symbol's Name
diff --git a/ld/testsuite/ld-x86-64/pr13082-5b.d b/ld/testsuite/ld-x86-64/pr13082-5b.d
index 48e37c3..1c5a5e7 100644
--- a/ld/testsuite/ld-x86-64/pr13082-5b.d
+++ b/ld/testsuite/ld-x86-64/pr13082-5b.d
@@ -6,7 +6,7 @@
 
 Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 1 entries:
  Offset     Info    Type                Sym. Value  Symbol's Name \+ Addend
-[0-9a-f]+ +[0-9a-f]+ +R_X86_64_RELATIVE +[0-9a-f]+
+[0-9a-f]+ +[0-9a-f]+ +R_X86_64_IRELATIVE +[0-9a-f]+
 
 Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entries:
  Offset     Info    Type                Sym. Value  Symbol's Name \+ Addend
diff --git a/ld/testsuite/ld-x86-64/pr13082-6a.d b/ld/testsuite/ld-x86-64/pr13082-6a.d
index de90bb8..9a1a655 100644
--- a/ld/testsuite/ld-x86-64/pr13082-6a.d
+++ b/ld/testsuite/ld-x86-64/pr13082-6a.d
@@ -6,7 +6,7 @@
 
 Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 1 entries:
  Offset     Info    Type                Sym. Value  Symbol's Name \+ Addend
-[0-9a-f]+ +[0-9a-f]+ +R_X86_64_RELATIVE +[0-9a-f]+
+[0-9a-f]+ +[0-9a-f]+ +R_X86_64_IRELATIVE +[0-9a-f]+
 
 Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entries:
  Offset     Info    Type                Sym. Value  Symbol's Name \+ Addend
diff --git a/ld/testsuite/ld-x86-64/pr13082-6b.d b/ld/testsuite/ld-x86-64/pr13082-6b.d
index 66ff59b..792c348 100644
--- a/ld/testsuite/ld-x86-64/pr13082-6b.d
+++ b/ld/testsuite/ld-x86-64/pr13082-6b.d
@@ -6,7 +6,7 @@
 
 Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 1 entries:
  Offset     Info    Type                Sym. Value  Symbol's Name \+ Addend
-[0-9a-f]+ +[0-9a-f]+ +R_X86_64_RELATIVE +[0-9a-f]+
+[0-9a-f]+ +[0-9a-f]+ +R_X86_64_IRELATIVE +[0-9a-f]+
 
 Relocation section '.rela.plt' at offset 0x[0-9a-f]+ contains 1 entries:
  Offset     Info    Type                Sym. Value  Symbol's Name \+ Addend
Follow-Ups:
- Re: PATCH: PR ld/13817: Broken IFUNC support
  - From: H.J. Lu
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