[binutils-gdb] Skip relocations in non-loaded, non-alloced sections

[H.J.Lu]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=081b1afe5a8cfa02bf3b3cdefb80c266705c17d1

commit 081b1afe5a8cfa02bf3b3cdefb80c266705c17d1
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Jun 16 05:52:34 2016 -0700

    Skip relocations in non-loaded, non-alloced sections
    
    Don't do anything special with non-loaded, non-alloced sections.
    In particular, any relocs in such sections should not affect GOT
    and PLT reference counting (ie. we don't allow them to create GOT
    or PLT entries), there's no possibility or desire to optimize TLS
    relocs, and there's not much point in propagating relocs to shared
    libs that the dynamic linker won't relocate.
    
    	* elf32-i386.c (elf_i386_check_relocs): Skip relocations in
    	non-loaded, non-alloced sections.
    	* elf64-x86-64.c (elf_x86_64_check_relocs): Likewise.

Diff:
---
 bfd/ChangeLog      |  6 ++++++
 bfd/elf32-i386.c   | 34 +++++++++++++++++++++-------------
 bfd/elf64-x86-64.c | 37 ++++++++++++++++++++++---------------
 3 files changed, 49 insertions(+), 28 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 344e08b..ad9e027 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2016-06-16  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* elf32-i386.c (elf_i386_check_relocs): Skip relocations in
+	non-loaded, non-alloced sections.
+	* elf64-x86-64.c (elf_x86_64_check_relocs): Likewise.
+
 2016-06-15  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* elf32-i386.c (elf_i386_check_relocs): Check SEC_ALLOC before
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 793fb39..a519778 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -1846,6 +1846,15 @@ elf_i386_check_relocs (bfd *abfd,
   if (bfd_link_relocatable (info))
     return TRUE;
 
+  /* Don't do anything special with non-loaded, non-alloced sections.
+     In particular, any relocs in such sections should not affect GOT
+     and PLT reference counting (ie. we don't allow them to create GOT
+     or PLT entries), there's no possibility or desire to optimize TLS
+     relocs, and there's not much point in propagating relocs to shared
+     libs that the dynamic linker won't relocate.  */
+  if ((sec->flags & SEC_ALLOC) == 0)
+    return TRUE;
+
   BFD_ASSERT (is_i386_elf (abfd));
 
   htab = elf_i386_hash_table (info);
@@ -2202,19 +2211,18 @@ do_size:
 	     may need to keep relocations for symbols satisfied by a
 	     dynamic library if we manage to avoid copy relocs for the
 	     symbol.  */
-	  if ((sec->flags & SEC_ALLOC) != 0
-	      && ((bfd_link_pic (info)
-		   && (r_type != R_386_PC32
-		       || (h != NULL
-			   && (! (bfd_link_pie (info)
-				  || SYMBOLIC_BIND (info, h))
-			       || h->root.type == bfd_link_hash_defweak
-			       || !h->def_regular))))
-		  || (ELIMINATE_COPY_RELOCS
-		      && !bfd_link_pic (info)
-		      && h != NULL
-		      && (h->root.type == bfd_link_hash_defweak
-			  || !h->def_regular))))
+	  if ((bfd_link_pic (info)
+	       && (r_type != R_386_PC32
+		   || (h != NULL
+		       && (! (bfd_link_pie (info)
+			      || SYMBOLIC_BIND (info, h))
+			   || h->root.type == bfd_link_hash_defweak
+			   || !h->def_regular))))
+	      || (ELIMINATE_COPY_RELOCS
+		  && !bfd_link_pic (info)
+		  && h != NULL
+		  && (h->root.type == bfd_link_hash_defweak
+		      || !h->def_regular)))
 	    {
 	      struct elf_dyn_relocs *p;
 	      struct elf_dyn_relocs **head;
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 8c8bcce..9044aab 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -2143,6 +2143,15 @@ elf_x86_64_check_relocs (bfd *abfd, struct bfd_link_info *info,
   if (bfd_link_relocatable (info))
     return TRUE;
 
+  /* Don't do anything special with non-loaded, non-alloced sections.
+     In particular, any relocs in such sections should not affect GOT
+     and PLT reference counting (ie. we don't allow them to create GOT
+     or PLT entries), there's no possibility or desire to optimize TLS
+     relocs, and there's not much point in propagating relocs to shared
+     libs that the dynamic linker won't relocate.  */
+  if ((sec->flags & SEC_ALLOC) == 0)
+    return TRUE;
+
   BFD_ASSERT (is_x86_64_elf (abfd));
 
   htab = elf_x86_64_hash_table (info);
@@ -2518,8 +2527,7 @@ elf_x86_64_check_relocs (bfd *abfd, struct bfd_link_info *info,
 		      && h != NULL
 		      && !h->def_regular
 		      && h->def_dynamic
-		      && (sec->flags & SEC_READONLY) == 0))
-	      && (sec->flags & SEC_ALLOC) != 0)
+		      && (sec->flags & SEC_READONLY) == 0)))
 	    return elf_x86_64_need_pic (abfd, sec, h, symtab_hdr, isym,
 					&x86_64_elf_howto_table[r_type]);
 	  /* Fall through.  */
@@ -2601,19 +2609,18 @@ do_size:
 	     may need to keep relocations for symbols satisfied by a
 	     dynamic library if we manage to avoid copy relocs for the
 	     symbol.  */
-	  if ((sec->flags & SEC_ALLOC) != 0
-	      && ((bfd_link_pic (info)
-		   && (! IS_X86_64_PCREL_TYPE (r_type)
-		       || (h != NULL
-			   && (! (bfd_link_pie (info)
-				  || SYMBOLIC_BIND (info, h))
-			       || h->root.type == bfd_link_hash_defweak
-			       || !h->def_regular))))
-		  || (ELIMINATE_COPY_RELOCS
-		      && !bfd_link_pic (info)
-		      && h != NULL
-		      && (h->root.type == bfd_link_hash_defweak
-			  || !h->def_regular))))
+	  if ((bfd_link_pic (info)
+	       && (! IS_X86_64_PCREL_TYPE (r_type)
+		   || (h != NULL
+		       && (! (bfd_link_pie (info)
+			      || SYMBOLIC_BIND (info, h))
+			   || h->root.type == bfd_link_hash_defweak
+			   || !h->def_regular))))
+	      || (ELIMINATE_COPY_RELOCS
+		  && !bfd_link_pic (info)
+		  && h != NULL
+		  && (h->root.type == bfd_link_hash_defweak
+		      || !h->def_regular)))
 	    {
 	      struct elf_dyn_relocs *p;
 	      struct elf_dyn_relocs **head;