[binutils-gdb] ld: Set non_ir_ref_regular on symbols referenced in regular objects

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

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=a83ef4d139c377e0e87d105977d85c6ef9fbb162

commit a83ef4d139c377e0e87d105977d85c6ef9fbb162
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Nov 28 03:48:25 2017 -0800

    ld: Set non_ir_ref_regular on symbols referenced in regular objects
    
    If linker plugin is enabled, set non_ir_ref_regular on symbols referenced
    in regular objects so that linker plugin will get the correct symbol
    resolution.
    
    bfd/
    
    	PR ld/22502
    	* elflink.c (_bfd_elf_merge_symbol): Also skip definition from
    	an IR object.
    	(elf_link_add_object_symbols): If linker plugin is enabled, set
    	non_ir_ref_regular on symbols referenced in regular objects so
    	that linker plugin will get the correct symbol resolution.
    
    ld/
    
    	PR ld/22502
    	* testsuite/ld-plugin/lto.exp: Run PR ld/22502 test.
    	* testsuite/ld-plugin/pr22502a.c: New file.
    	* testsuite/ld-plugin/pr22502b.c: Likewise.

Diff:
---
 bfd/ChangeLog                     |  9 ++++++
 bfd/elflink.c                     | 68 +++++++++++++++++++++++++++++++++++++--
 ld/ChangeLog                      |  7 ++++
 ld/testsuite/ld-plugin/lto.exp    |  9 ++++++
 ld/testsuite/ld-plugin/pr22502a.c | 16 +++++++++
 ld/testsuite/ld-plugin/pr22502b.c |  3 ++
 6 files changed, 109 insertions(+), 3 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 3903b1d..abd7c96 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,12 @@
+2017-11-28  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/22502
+	* elflink.c (_bfd_elf_merge_symbol): Also skip definition from
+	an IR object.
+	(elf_link_add_object_symbols): If linker plugin is enabled, set
+	non_ir_ref_regular on symbols referenced in regular objects so
+	that linker plugin will get the correct symbol resolution.
+
 2017-11-27  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
 	PR ld/22263
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 99f867d..ddd088c 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -1555,10 +1555,13 @@ _bfd_elf_merge_symbol (bfd *abfd,
       sec = *psec;
     }
 
-  /* There are multiple definitions of a normal symbol.
-     Skip the default symbol as well.  */
+  /* There are multiple definitions of a normal symbol.  Skip the
+     default symbol as well as definition from an IR object.  */
   if (olddef && !olddyn && !oldweak && newdef && !newdyn && !newweak
-      && !default_sym && h->def_regular)
+      && !default_sym && h->def_regular
+      && !(oldbfd != NULL
+	   && (oldbfd->flags & BFD_PLUGIN) != 0
+	   && (abfd->flags & BFD_PLUGIN) == 0))
     {
       /* Handle a multiple definition.  */
       (*info->callbacks->multiple_definition) (info, &h->root,
@@ -4931,6 +4934,65 @@ error_free_dyn:
 	}
     }
 
+  if (info->lto_plugin_active
+      && !bfd_link_relocatable (info)
+      && (abfd->flags & BFD_PLUGIN) == 0
+      && !just_syms
+      && extsymcount)
+    {
+      int r_sym_shift;
+
+      if (bed->s->arch_size == 32)
+	r_sym_shift = 8;
+      else
+	r_sym_shift = 32;
+
+      /* If linker plugin is enabled, set non_ir_ref_regular on symbols
+	 referenced in regular objects so that linker plugin will get
+	 the correct symbol resolution.  */
+
+      sym_hash = elf_sym_hashes (abfd);
+      for (s = abfd->sections; s != NULL; s = s->next)
+	{
+	  Elf_Internal_Rela *internal_relocs;
+	  Elf_Internal_Rela *rel, *relend;
+
+	  /* Don't check relocations in excluded sections.  */
+	  if ((s->flags & SEC_RELOC) == 0
+	      || s->reloc_count == 0
+	      || (s->flags & SEC_EXCLUDE) != 0
+	      || ((info->strip == strip_all
+		   || info->strip == strip_debugger)
+		  && (s->flags & SEC_DEBUGGING) != 0))
+	    continue;
+
+	  internal_relocs = _bfd_elf_link_read_relocs (abfd, s, NULL,
+						       NULL,
+						       info->keep_memory);
+	  if (internal_relocs == NULL)
+	    goto error_free_vers;
+
+	  rel = internal_relocs;
+	  relend = rel + s->reloc_count;
+	  for ( ; rel < relend; rel++)
+	    {
+	      unsigned long r_symndx = rel->r_info >> r_sym_shift;
+	      struct elf_link_hash_entry *h;
+
+	      /* Skip local symbols.  */
+	      if (r_symndx < extsymoff)
+		continue;
+
+	      h = sym_hash[r_symndx - extsymoff];
+	      if (h != NULL)
+		h->root.non_ir_ref_regular = 1;
+	    }
+
+	  if (elf_section_data (s)->relocs != internal_relocs)
+	    free (internal_relocs);
+	}
+    }
+
   if (extversym != NULL)
     {
       free (extversym);
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 9c10c7e..ed63236 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,10 @@
+2017-11-28  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/22502
+	* testsuite/ld-plugin/lto.exp: Run PR ld/22502 test.
+	* testsuite/ld-plugin/pr22502a.c: New file.
+	* testsuite/ld-plugin/pr22502b.c: Likewise.
+
 2017-11-24  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* testsuite/ld-elf/pr21562c.t: Also provide ___start_scnfoo and
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index d34479f..56c852d 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -208,6 +208,12 @@ set lto_link_tests [list \
    "-flto -Wl,-plugin,$plug_so" "-flto" \
    {pr20321.c} {{warning ".*: duplicated plugin"}} \
    "pr20321" "c"] \
+  [list "Build pr22502a.o" \
+   "" "" \
+   {pr22502a.c}] \
+  [list "Build pr22502b.o" \
+   "$plug_opt" "-flto $lto_no_fat" \
+   {pr22502b.c}] \
 ]
 
 if { [at_least_gcc_version 4 7] } {
@@ -391,6 +397,9 @@ set lto_run_tests [list \
   [list "Run pr20267b" \
    "-O2 -flto tmpdir/pr20267a.o tmpdir/libpr20267b.a" "" \
    {dummy.c} "pr20267b" "pass.out" "-flto -O2" "c"] \
+  [list "Run pr22502" \
+   "-O2 -flto tmpdir/pr22502a.o tmpdir/pr22502b.o" "" \
+   {dummy.c} "pr20267" "pass.out" "-flto -O2" "c"] \
 ]
 
 if { [at_least_gcc_version 4 7] } {
diff --git a/ld/testsuite/ld-plugin/pr22502a.c b/ld/testsuite/ld-plugin/pr22502a.c
new file mode 100644
index 0000000..0eaa1af
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr22502a.c
@@ -0,0 +1,16 @@
+#include <stdio.h>
+
+volatile int x;
+extern void abort ();
+
+__attribute__((weak))
+void foobar (void) { x++; }
+
+int main (void)
+{
+  foobar ();
+  if (x != -1)
+    abort ();
+  printf ("PASS\n");
+  return 0;
+}
diff --git a/ld/testsuite/ld-plugin/pr22502b.c b/ld/testsuite/ld-plugin/pr22502b.c
new file mode 100644
index 0000000..87389b9
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr22502b.c
@@ -0,0 +1,3 @@
+extern volatile int x;
+
+void foobar (void) { x--; }