Support garbage collection against STT_GNU_IFUNC symbols.

bfd/

2010-07-13  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/11791
	* elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Support
	garbage collection against STT_GNU_IFUNC symbols.

	* elf32-i386.c (elf_i386_get_local_sym_hash): Don't set
	elf.plt.offset/elf.got.offset to -1.
	(elf_i386_tls_transition): Skip TLS transition for functions.
	(elf_i386_gc_sweep_hook): Support STT_GNU_IFUNC symbols.

	* elf64-x86-64.c (elf64_x86_64_get_local_sym_hash): Don't set
	elf.plt.offset/elf.got.offset to -1.
	(elf64_x86_64_tls_transition): Skip TLS transition for functions.
	(elf64_x86_64_gc_sweep_hook): Support STT_GNU_IFUNC symbols.

ld/testsuite/

2010-07-13  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/11791
	* ld-ifunc/ifunc-10-i386.d: New.
	* ld-ifunc/ifunc-10-i386.s: Likewise.
	* ld-ifunc/ifunc-10-x86-64.d: Likewise.
	* ld-ifunc/ifunc-10-x86-64.s: Likewise.
	* ld-ifunc/ifunc-11-i386.d: Likewise.
	* ld-ifunc/ifunc-11-i386.s: Likewise.
	* ld-ifunc/ifunc-11-x86-64.d: Likewise.
	* ld-ifunc/ifunc-11-x86-64.s: Likewise.

13 files changed, 210 insertions, 4 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 32c44a9..e12771a 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,19 @@
+2010-07-13  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/11791
+	* elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Support
+	garbage collection against STT_GNU_IFUNC symbols.
+
+	* elf32-i386.c (elf_i386_get_local_sym_hash): Don't set
+	elf.plt.offset/elf.got.offset to -1.
+	(elf_i386_tls_transition): Skip TLS transition for functions.
+	(elf_i386_gc_sweep_hook): Support STT_GNU_IFUNC symbols.
+
+	* elf64-x86-64.c (elf64_x86_64_get_local_sym_hash): Don't set
+	elf.plt.offset/elf.got.offset to -1.
+	(elf64_x86_64_tls_transition): Skip TLS transition for functions.
+	(elf64_x86_64_gc_sweep_hook): Support STT_GNU_IFUNC symbols.
+
 2010-07-12  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* elf32-i386.c (elf_i386_check_relocs): Re-indent.
diff --git a/bfd/elf-ifunc.c b/bfd/elf-ifunc.c
index 0de236f..760fc26 100644
--- a/bfd/elf-ifunc.c
+++ b/bfd/elf-ifunc.c
@@ -187,6 +187,15 @@ _bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
 
   htab = elf_hash_table (info);
 
+  /* Support garbage collection against STT_GNU_IFUNC symbols.  */
+  if (h->plt.refcount <= 0 && h->got.refcount <= 0)
+    {
+      h->got = htab->init_got_offset;
+      h->plt = htab->init_plt_offset;
+      *head = NULL;
+      return TRUE;
+    }
+
   /* Return and discard space for dynamic relocations against it if
      it is never referenced in a non-shared object.  */
   if (!h->ref_regular)
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index e85a7e5..ac9bdb6 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -789,8 +789,6 @@ elf_i386_get_local_sym_hash (struct elf_i386_link_hash_table *htab,
       ret->elf.indx = sec->id;
       ret->elf.dynstr_index = ELF32_R_SYM (rel->r_info);
       ret->elf.dynindx = -1;
-      ret->elf.plt.offset = (bfd_vma) -1;
-      ret->elf.got.offset = (bfd_vma) -1;
       *slot = ret;
     }
   return &ret->elf;
@@ -1162,6 +1160,12 @@ elf_i386_tls_transition (struct bfd_link_info *info, bfd *abfd,
   unsigned int to_type = from_type;
   bfd_boolean check = TRUE;
 
+  /* Skip TLS transition for functions.  */
+  if (h != NULL
+      && (h->type == STT_FUNC
+	  || h->type == STT_GNU_IFUNC))
+    return TRUE;
+
   switch (from_type)
     {
     case R_386_TLS_GD:
@@ -1819,6 +1823,23 @@ elf_i386_gc_sweep_hook (bfd *abfd,
 		break;
 	      }
 	}
+      else
+	{
+	  /* A local symbol.  */
+	  Elf_Internal_Sym *isym;
+
+	  isym = bfd_sym_from_r_symndx (&htab->sym_cache,
+					abfd, r_symndx);
+
+	  /* Check relocation against local STT_GNU_IFUNC symbol.  */
+	  if (isym != NULL
+	      && ELF32_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
+	    {
+	      h = elf_i386_get_local_sym_hash (htab, abfd, rel, FALSE);
+	      if (h == NULL)
+		abort ();
+	    }
+	}
 
       r_type = ELF32_R_TYPE (rel->r_info);
       if (! elf_i386_tls_transition (info, abfd, sec, NULL,
@@ -1845,6 +1866,11 @@ elf_i386_gc_sweep_hook (bfd *abfd,
 	    {
 	      if (h->got.refcount > 0)
 		h->got.refcount -= 1;
+	      if (h->type == STT_GNU_IFUNC)
+		{
+		  if (h->plt.refcount > 0)
+		    h->plt.refcount -= 1;
+		}
 	    }
 	  else if (local_got_refcounts != NULL)
 	    {
@@ -1867,6 +1893,16 @@ elf_i386_gc_sweep_hook (bfd *abfd,
 	    }
 	  break;
 
+	case R_386_GOTOFF:
+	  if (h != NULL && h->type == STT_GNU_IFUNC)
+	    {
+	      if (h->got.refcount > 0)
+		h->got.refcount -= 1;
+	      if (h->plt.refcount > 0)
+		h->plt.refcount -= 1;
+	    }
+	  break;
+
 	default:
 	  break;
 	}
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 21524fa..108f257 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -603,8 +603,6 @@ elf64_x86_64_get_local_sym_hash (struct elf64_x86_64_link_hash_table *htab,
       ret->elf.indx = sec->id;
       ret->elf.dynstr_index = ELF64_R_SYM (rel->r_info);
       ret->elf.dynindx = -1;
-      ret->elf.plt.offset = (bfd_vma) -1;
-      ret->elf.got.offset = (bfd_vma) -1;
       *slot = ret;
     }
   return &ret->elf;
@@ -951,6 +949,12 @@ elf64_x86_64_tls_transition (struct bfd_link_info *info, bfd *abfd,
   unsigned int to_type = from_type;
   bfd_boolean check = TRUE;
 
+  /* Skip TLS transition for functions.  */
+  if (h != NULL
+      && (h->type == STT_FUNC
+	  || h->type == STT_GNU_IFUNC))
+    return TRUE;
+
   switch (from_type)
     {
     case R_X86_64_TLSGD:
@@ -1657,6 +1661,24 @@ elf64_x86_64_gc_sweep_hook (bfd *abfd, struct bfd_link_info *info,
 		break;
 	      }
 	}
+      else
+	{
+	  /* A local symbol.  */
+	  Elf_Internal_Sym *isym;
+
+	  isym = bfd_sym_from_r_symndx (&htab->sym_cache,
+					abfd, r_symndx);
+
+	  /* Check relocation against local STT_GNU_IFUNC symbol.  */
+	  if (isym != NULL
+	      && ELF64_ST_TYPE (isym->st_info) == STT_GNU_IFUNC)
+	    {
+	      h = elf64_x86_64_get_local_sym_hash (htab, abfd, rel,
+						   FALSE);
+	      if (h == NULL)
+		abort ();
+	    }
+	}
 
       r_type = ELF64_R_TYPE (rel->r_info);
       if (! elf64_x86_64_tls_transition (info, abfd, sec, NULL,
@@ -1687,6 +1709,11 @@ elf64_x86_64_gc_sweep_hook (bfd *abfd, struct bfd_link_info *info,
 	        h->plt.refcount -= 1;
 	      if (h->got.refcount > 0)
 		h->got.refcount -= 1;
+	      if (h->type == STT_GNU_IFUNC)
+		{
+		  if (h->plt.refcount > 0)
+		    h->plt.refcount -= 1;
+		}
 	    }
 	  else if (local_got_refcounts != NULL)
 	    {
diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index 463a14c..6755523 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,15 @@
+2010-07-13  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/11791
+	* ld-ifunc/ifunc-10-i386.d: New.
+	* ld-ifunc/ifunc-10-i386.s: Likewise.
+	* ld-ifunc/ifunc-10-x86-64.d: Likewise.
+	* ld-ifunc/ifunc-10-x86-64.s: Likewise.
+	* ld-ifunc/ifunc-11-i386.d: Likewise.
+	* ld-ifunc/ifunc-11-i386.s: Likewise.
+	* ld-ifunc/ifunc-11-x86-64.d: Likewise.
+	* ld-ifunc/ifunc-11-x86-64.s: Likewise.
+
 2010-07-06  Alan Modra  <amodra@gmail.com>
 
 	* ld-powerpc/relax.s: Add branch back to _start.
diff --git a/ld/testsuite/ld-ifunc/ifunc-10-i386.d b/ld/testsuite/ld-ifunc/ifunc-10-i386.d
new file mode 100644
index 0000000..5f56b24
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/ifunc-10-i386.d
@@ -0,0 +1,6 @@
+#ld: -m elf_i386 -e bar --gc-sections
+#as: --32
+#readelf: -r --wide
+#target: x86_64-*-* i?86-*-*
+
+There are no relocations in this file.
diff --git a/ld/testsuite/ld-ifunc/ifunc-10-i386.s b/ld/testsuite/ld-ifunc/ifunc-10-i386.s
new file mode 100644
index 0000000..8411e81
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/ifunc-10-i386.s
@@ -0,0 +1,20 @@
+        .section .text.foo,"ax",@progbits
+        .type foo, @function
+foo:
+        .global foo
+        movl ifunc@GOT(%ecx), %eax
+        movl ifunc@GOTOFF(%ecx), %eax
+	call ifunc@PLT
+	call ifunc
+        ret
+
+        .section .text.bar,"ax",@progbits
+        .type bar, @function
+bar:
+        .global bar
+        ret
+
+        .section .text.ifunc,"ax",@progbits
+        .type ifunc, @gnu_indirect_function
+ifunc:
+        ret
diff --git a/ld/testsuite/ld-ifunc/ifunc-10-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-10-x86-64.d
new file mode 100644
index 0000000..8ece379
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/ifunc-10-x86-64.d
@@ -0,0 +1,6 @@
+#ld: -m elf_x86_64 -e bar --gc-sections
+#as: --64
+#readelf: -r --wide
+#target: x86_64-*-*
+
+There are no relocations in this file.
diff --git a/ld/testsuite/ld-ifunc/ifunc-10-x86-64.s b/ld/testsuite/ld-ifunc/ifunc-10-x86-64.s
new file mode 100644
index 0000000..ea6f8c2
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/ifunc-10-x86-64.s
@@ -0,0 +1,20 @@
+        .section .text.foo,"ax",@progbits
+        .type foo, @function
+foo:
+        .global foo
+        movl ifunc@GOTPCREL(%rip), %eax
+        movl ifunc(%rip), %eax
+	call ifunc@PLT
+	call ifunc
+        ret
+
+        .section .text.bar,"ax",@progbits
+        .type bar, @function
+bar:
+        .global bar
+        ret
+
+        .section .text.ifunc,"ax",@progbits
+        .type ifunc, @gnu_indirect_function
+ifunc:
+        ret
diff --git a/ld/testsuite/ld-ifunc/ifunc-11-i386.d b/ld/testsuite/ld-ifunc/ifunc-11-i386.d
new file mode 100644
index 0000000..5f56b24
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/ifunc-11-i386.d
@@ -0,0 +1,6 @@
+#ld: -m elf_i386 -e bar --gc-sections
+#as: --32
+#readelf: -r --wide
+#target: x86_64-*-* i?86-*-*
+
+There are no relocations in this file.
diff --git a/ld/testsuite/ld-ifunc/ifunc-11-i386.s b/ld/testsuite/ld-ifunc/ifunc-11-i386.s
new file mode 100644
index 0000000..06f5924
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/ifunc-11-i386.s
@@ -0,0 +1,21 @@
+        .section .text.foo,"ax",@progbits
+        .type foo, @function
+foo:
+        .global foo
+        movl ifunc@GOT(%ecx), %eax
+	movl ifunc@GOTOFF(%ecx), %eax
+	call ifunc@PLT
+	call ifunc
+        ret
+
+        .section .text.bar,"ax",@progbits
+        .type bar, @function
+bar:
+        .global bar
+        ret
+
+        .section .text.ifunc,"ax",@progbits
+        .type ifunc, @gnu_indirect_function
+        .global ifunc
+ifunc:
+        ret
diff --git a/ld/testsuite/ld-ifunc/ifunc-11-x86-64.d b/ld/testsuite/ld-ifunc/ifunc-11-x86-64.d
new file mode 100644
index 0000000..8ece379
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/ifunc-11-x86-64.d
@@ -0,0 +1,6 @@
+#ld: -m elf_x86_64 -e bar --gc-sections
+#as: --64
+#readelf: -r --wide
+#target: x86_64-*-*
+
+There are no relocations in this file.
diff --git a/ld/testsuite/ld-ifunc/ifunc-11-x86-64.s b/ld/testsuite/ld-ifunc/ifunc-11-x86-64.s
new file mode 100644
index 0000000..70d4fbf
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/ifunc-11-x86-64.s
@@ -0,0 +1,21 @@
+        .section .text.foo,"ax",@progbits
+        .type foo, @function
+foo:
+        .global foo
+        movl ifunc@GOTPCREL(%rip), %eax
+        movl ifunc(%rip), %eax
+	call ifunc@PLT
+	call ifunc
+        ret
+
+        .section .text.bar,"ax",@progbits
+        .type bar, @function
+bar:
+        .global bar
+        ret
+
+        .section .text.ifunc,"ax",@progbits
+        .type ifunc, @gnu_indirect_function
+        .global ifunc
+ifunc:
+        ret