This is the mail archive of the binutils-cvs@sourceware.org mailing list for the binutils project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[binutils-gdb/binutils-2_29-branch] PR ld/20125, MMIX weak symbols


https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0f39cf99f59b4bd9d15a3d03d397cb1feaca2a03

commit 0f39cf99f59b4bd9d15a3d03d397cb1feaca2a03
Author: Hans-Peter Nilsson <hp@bitrange.com>
Date:   Thu Sep 14 05:03:14 2017 +0200

    PR ld/20125, MMIX weak symbols
    
    Weak undefineds with PUSHJ relocs were "lost", causing internal
    inconsistencies and an abort.
    
    Import from mainline.

Diff:
---
 bfd/ChangeLog                  |  8 ++++++++
 bfd/elf64-mmix.c               | 23 +++++++++++++++++------
 ld/ChangeLog                   |  8 ++++++++
 ld/testsuite/ld-mmix/pr20125.d | 21 +++++++++++++++++++++
 ld/testsuite/ld-mmix/pr20125.s |  2 ++
 5 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index ed97efc..aca2459 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,11 @@
+2017-08-21  Hans-Peter Nilsson  <hp@bitrange.com>
+
+	Import from mainline:
+
+	PR ld/20125
+	* elf64-mmix.c (mmix_elf_relax_section): Correct handling of
+	undefined weak symbols.
+
 2017-09-10  Nick Clifton  <nickc@redhat.com>
 
 	Import from mainline:
diff --git a/bfd/elf64-mmix.c b/bfd/elf64-mmix.c
index b4ff5a3..12c7c3b 100644
--- a/bfd/elf64-mmix.c
+++ b/bfd/elf64-mmix.c
@@ -2712,8 +2712,21 @@ mmix_elf_relax_section (bfd *abfd,
 	  indx = ELF64_R_SYM (irel->r_info) - symtab_hdr->sh_info;
 	  h = elf_sym_hashes (abfd)[indx];
 	  BFD_ASSERT (h != NULL);
-	  if (h->root.type != bfd_link_hash_defined
-	      && h->root.type != bfd_link_hash_defweak)
+	  if (h->root.type == bfd_link_hash_undefweak)
+	    /* FIXME: for R_MMIX_PUSHJ_STUBBABLE, there are alternatives to
+	       the canonical value 0 for an unresolved weak symbol to
+	       consider: as the debug-friendly approach, resolve to "abort"
+	       (or a port-specific function), or as the space-friendly
+	       approach resolve to the next instruction (like some other
+	       ports, notably ARM and AArch64).  These alternatives require
+	       matching code in mmix_elf_perform_relocation or its caller.  */
+	    symval = 0;
+	  else if (h->root.type == bfd_link_hash_defined
+		   || h->root.type == bfd_link_hash_defweak)
+	    symval = (h->root.u.def.value
+		      + h->root.u.def.section->output_section->vma
+		      + h->root.u.def.section->output_offset);
+	  else
 	    {
 	      /* This appears to be a reference to an undefined symbol.  Just
 		 ignore it--it will be caught by the regular reloc processing.
@@ -2727,10 +2740,6 @@ mmix_elf_relax_section (bfd *abfd,
 		}
 	      continue;
 	    }
-
-	  symval = (h->root.u.def.value
-		    + h->root.u.def.section->output_section->vma
-		    + h->root.u.def.section->output_offset);
 	}
 
       if (ELF64_R_TYPE (irel->r_info) == (int) R_MMIX_PUSHJ_STUBBABLE)
@@ -2868,6 +2877,8 @@ mmix_elf_relax_section (bfd *abfd,
 	}
     }
 
+  BFD_ASSERT(pjsno == mmix_elf_section_data (sec)->pjs.n_pushj_relocs);
+
   if (internal_relocs != NULL
       && elf_section_data (sec)->relocs != internal_relocs)
     free (internal_relocs);
diff --git a/ld/ChangeLog b/ld/ChangeLog
index f1acd5b..d81e948 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,11 @@
+2017-08-21  Hans-Peter Nilsson  <hp@bitrange.com>
+
+	Import from mainline:
+
+	PR ld/20125
+	* testsuite/ld-mmix/pr20125.d, testsuite/ld-mmix/pr20125.s: New
+	test.
+
 2017-09-10  Alan Modra  <amodra@gmail.com>
 
 	* ld.texinfo (--plt-align): Describe new behaviour of option.
diff --git a/ld/testsuite/ld-mmix/pr20125.d b/ld/testsuite/ld-mmix/pr20125.d
new file mode 100644
index 0000000..7c09c04
--- /dev/null
+++ b/ld/testsuite/ld-mmix/pr20125.d
@@ -0,0 +1,21 @@
+#as: -no-predefined-syms -x -I$srcdir/$subdir
+#ld: -m mmo --defsym __.MMIX.start..text=0x80000
+#objdump: -dr
+
+# PUSHJ reloc handling was wrong for weak undefined symbols, causing
+# internal inconsistencies, leading to a call to abort.
+# Note that we don't keep track of which symbols have pushj-stubs, so
+# we get one stub each for the two calls to "foo".
+
+.*:     file format mmo
+
+Disassembly of section \.text:
+
+0+80000 <(_start|Main)>:
+   80000:	fe000004 	get \$0,rJ
+   80004:	f2010004 	pushj \$1,80014 <Main\+0x14>
+   80008:	f2010004 	pushj \$1,80018 <Main\+0x18>
+   8000c:	f6040000 	put rJ,\$0
+   80010:	f8010000 	pop 1,0
+   80014:	f1fdfffb 	jmp 0 <Main-0x80000>
+   80018:	f1fdfffa 	jmp 0 <Main-0x80000>
diff --git a/ld/testsuite/ld-mmix/pr20125.s b/ld/testsuite/ld-mmix/pr20125.s
new file mode 100644
index 0000000..e528d9d
--- /dev/null
+++ b/ld/testsuite/ld-mmix/pr20125.s
@@ -0,0 +1,2 @@
+	.weak bar
+	.include "pr12815-2.s"


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]