[patch] Fix other cases of C++ no .eh_frame_hdr table will be created (PR 6893)

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

my former mail http://sourceware.org/ml/binutils/2008-09/msg00124.html fixed:
/usr/bin/ld: error in /home/aph/llvm/Release/lib/LLVMInterpreter.o(.eh_frame); no .eh_frame_hdr table will be created.

It had AFAIK no regressions but still in some cases the problem remained the
same, at least when discarded FDE of .eh_frame was referencing (non-discarded)
.gcc_except_table (through LSDA) as the new sanity check failed then.

Regression tested on 86 arch targets, asking for a commit approval incl. the
comment validity review.  Bugreported by Brad Settlemyer.


Thanks,
Jan


bfd/
2009-01-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* elf-eh-frame.c (REQUIRE_CLEARED_RELOCS) Remove.
	(_bfd_elf_parse_eh_frame): Do not check relocations for removed FDEs.

ld/testsuite/
2009-01-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* ld-elf/eh-group2.s: New `.cfi_lsda' referencing `.gcc_except_table'.
	* ld-elf/eh-group.exp: New test and conditional defininiton of `ELF64'.

--- bfd/elf-eh-frame.c	17 Sep 2008 07:50:28 -0000	1.73
+++ bfd/elf-eh-frame.c	30 Jan 2009 21:44:01 -0000
@@ -549,16 +549,6 @@ _bfd_elf_parse_eh_frame (bfd *abfd, stru
 	     < (bfd_size_type) ((buf) - ehbuf)))	\
     cookie->rel++
 
-#define REQUIRE_CLEARED_RELOCS(buf)			\
-  while (cookie->rel < cookie->relend			\
-	 && (cookie->rel->r_offset			\
-	     < (bfd_size_type) ((buf) - ehbuf)))	\
-    {							\
-      REQUIRE (cookie->rel->r_info == 0);		\
-      REQUIRE (cookie->rel->r_addend == 0);		\
-      cookie->rel++;					\
-    }
-
 #define GET_RELOC(buf)					\
   ((cookie->rel < cookie->relend			\
     && (cookie->rel->r_offset				\
@@ -817,16 +807,16 @@ _bfd_elf_parse_eh_frame (bfd *abfd, stru
 
 	  buf = last_fde + 4 + hdr_length;
 
-	  /* Cleared FDE?  The instructions will not be cleared but verify all
-	     the relocation entries for them are cleared.  */
-	  if (rsec == NULL)
-	    {
-	      REQUIRE_CLEARED_RELOCS (buf);
-	    }
-	  else
-	    {
-	      SKIP_RELOCS (buf);
-	    }
+	  /* For NULL RSEC (cleared FDE belonging to a discarded section)
+	     the relocations are commonly cleared.  We do not sanity check if
+	     all these relocations are cleared as (1) relocations to
+	     .gcc_except_table will remain uncleared (they will get dropped
+	     with the drop of this unused FDE) and (2) BFD already safely drops
+	     relocations of any type in .eh_frame by
+	     elf_section_ignore_discarded_relocs.
+	     TODO: The .gcc_except_table entries should be also filtered as
+	     .eh_frame entries; or GCC could rather use COMDAT for them.  */
+	  SKIP_RELOCS (buf);
 	}
 
       /* Try to interpret the CFA instructions and find the first
--- ld/testsuite/ld-elf/eh-group.exp	25 Sep 2008 03:16:42 -0000	1.3
+++ ld/testsuite/ld-elf/eh-group.exp	30 Jan 2009 21:44:01 -0000
@@ -40,12 +40,28 @@ if ![is_elf_format] {
     return
 }
 
-set build_tests_ld {
-  {"Build eh-group1.o"
-   "-r" ""
-   {eh-group1.s eh-group2.s} {} "eh-group.o"}
+# alpha-linux-gnu does not support 64-bit relocations:
+#   relocation truncated to fit: REFLONG against `.gcc_except_table'
+# arm-eabi does not support 64-bit relocations:
+#   bad relocation fixup type (1)
+set testname "Guess the target size from eh-group1size.o"
+if [ld_assemble $as "$srcdir/$subdir/eh-group1.s" "tmpdir/eh-group1size.o"] {
+    pass $testname
+} else {
+    fail $testname
 }
 
+set as_options ""
+if [is_elf64 "tmpdir/eh-group1size.o"] {
+    set as_options "$as_options --defsym ELF64=1"
+}
+
+set build_tests_ld [list			\
+  [list "Build eh-group1.o"			\
+   "-r" "$as_options"				\
+   {eh-group1.s eh-group2.s} {} "eh-group.o"]	\
+]
+
 run_ld_link_tests $build_tests_ld
 
 set testname "Link eh-group.o to eh-group"
--- ld/testsuite/ld-elf/eh-group2.s	20 Sep 2008 08:42:53 -0000	1.2
+++ ld/testsuite/ld-elf/eh-group2.s	30 Jan 2009 21:44:01 -0000
@@ -1,4 +1,15 @@
 	.section	sect, "axG", %progbits, sectgroup, comdat
 	.cfi_startproc
+# Test intention is that LSDA must be provided by the discarded FDE.
+# DW_EH_PE_udata8 = 4
+# DW_EH_PE_udata4 = 3
+	.ifdef		ELF64
+	.cfi_lsda 4, lsda
+	.else
+	.cfi_lsda 3, lsda
+	.endif
 	.skip 16
 	.cfi_endproc
+
+	.section	.gcc_except_table, "a", %progbits
+lsda: