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[patch] Fix C++ no .eh_frame_hdr table will be created (PR 6893)
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: binutils at sourceware dot org
- Date: Tue, 16 Sep 2008 16:08:07 +0200
- Subject: [patch] Fix C++ no .eh_frame_hdr table will be created (PR 6893)
Hi,
original bugreport by Andrew Haley:
1. svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm
2. cd llvm
3. ./configure \
--disable-static \
--enable-assertions \
--enable-debug-runtime \
--enable-jit \
--enable-optimized \
--enable-shared \
--enable-targets=host-only \
--with-pic \
--enable-pic \
--disable-binding
4. make VERBOSE=true
Actual results:/usr/bin/ld: error in
/home/aph/llvm/Release/lib/LLVMInterpreter.o(.eh_frame); no .eh_frame_hdr table will be created.
/usr/bin/ld: error in /home/aph/llvm/Release/lib/LLVMX86.o(.eh_frame); no .eh_frame_hdr table will be created.
/usr/bin/ld: error in /home/aph/llvm/Release/lib/LLVMExecutionEngine.o(.eh_frame); no .eh_frame_hdr table will be created.
/usr/bin/ld: error in /home/aph/llvm/Release/lib/LLVMJIT.o(.eh_frame); no .eh_frame_hdr table will be created.
------------------------------------------------------------------------------
These relocations
Relocation section '.rela.eh_frame' at offset 0x14b0 contains 2 entries:
Offset Info Type Sym. Value Sym. Name +
Addend
000000000020 000600000002 R_X86_64_PC32 0000000000000000 .text._ZNK4llvm13Targe + 0
with its target section .text._ZNK4llvm13 which is SHT_GROUP
[ 9] .text._ZNK4llvm13 PROGBITS 0000000000000000 000004c0
000000000000004f 0000000000000000 AXG 0 0 16
get converted to:
000000000020 000000000000 R_X86_64_NONE 0000000000000000
by this code:
../bfd/elf64-x86-64.c
if (sec != NULL && elf_discarded_section (sec))
{
/* For relocs against symbols from removed linkonce sections,
or sections discarded by a linker script, we just want the
section contents zeroed. Avoid any special processing. */
_bfd_clear_contents (howto, input_bfd, contents + rel->r_offset);
rel->r_info = 0;
rel->r_addend = 0;
continue;
}
ld will later error out on R_X86_64_NONE
The attached fix will properly discard those FDEs with discarded relocations
which can be verified in the testcase.
original bugreports:
https://bugzilla.redhat.com/show_bug.cgi?id=458950
https://bugzilla.redhat.com/show_bug.cgi?id=461675
Thanks,
Jan
bfd/
2008-09-16 Jan Kratochvil <jan.kratochvil@redhat.com>
PR 6893 - Do not consider FDEs for discarded sections as invalid.
* elf-eh-frame.c (_bfd_elf_parse_eh_frame): New REQUIRE_CLEARED_RELOCS.
Consider FDEs with cleared relocations as valid and ignorable.
ld/testsuite/
2008-09-16 Jan Kratochvil <jan.kratochvil@redhat.com>
* ld-elf/eh-group.exp, ld-elf/eh-group1.s, ld-elf/eh-group2.s: New test.
binutils/
2008-09-16 Jan Kratochvil <jan.kratochvil@redhat.com>
Suppress warnings on NONE relocations to discarded sections.
* readelf.c (is_none_reloc): New function.
(debug_apply_relocations): Ignore is_none_reloc() relocations.
--- bfd/elf-eh-frame.c 24 Aug 2008 21:43:00 -0000 1.72
+++ bfd/elf-eh-frame.c 16 Sep 2008 13:28:43 -0000
@@ -549,6 +549,16 @@ _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 \
@@ -766,9 +776,14 @@ _bfd_elf_parse_eh_frame (bfd *abfd, stru
/* Chain together the FDEs for each section. */
rsec = _bfd_elf_gc_mark_rsec (info, sec, gc_mark_hook, cookie);
- REQUIRE (rsec && rsec->owner == abfd);
- this_inf->u.fde.next_for_section = elf_fde_list (rsec);
- elf_fde_list (rsec) = this_inf;
+ /* RSEC will be NULL if FDE was cleared out as it was belonging to
+ a discarded SHT_GROUP. */
+ if (rsec)
+ {
+ REQUIRE (rsec->owner == abfd);
+ this_inf->u.fde.next_for_section = elf_fde_list (rsec);
+ elf_fde_list (rsec) = this_inf;
+ }
/* Skip the initial location and address range. */
start = buf;
@@ -801,7 +816,17 @@ _bfd_elf_parse_eh_frame (bfd *abfd, stru
insns = buf;
buf = last_fde + 4 + hdr_length;
- SKIP_RELOCS (buf);
+
+ /* 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);
+ }
}
/* Try to interpret the CFA instructions and find the first
--- binutils/readelf.c 5 Sep 2008 14:49:05 -0000 1.425
+++ binutils/readelf.c 16 Sep 2008 13:28:50 -0000
@@ -8284,6 +8284,53 @@ is_16bit_abs_reloc (unsigned int reloc_t
}
}
+/* Returns TRUE iff RELOC_TYPE is a NONE relocation used for discarded
+ relocation entries (possibly formerly used for SHT_GROUP sections). */
+
+static bfd_boolean
+is_none_reloc (unsigned int reloc_type)
+{
+ switch (elf_header.e_machine)
+ {
+ case EM_68K:
+ return reloc_type == 0; /* R_68K_NONE. */
+ case EM_386:
+ return reloc_type == 0; /* R_386_NONE. */
+ case EM_SPARC32PLUS:
+ case EM_SPARCV9:
+ case EM_SPARC:
+ return reloc_type == 0; /* R_SPARC_NONE. */
+ case EM_MIPS:
+ return reloc_type == 0; /* R_MIPS_NONE. */
+ case EM_PARISC:
+ return reloc_type == 0; /* R_PARISC_NONE. */
+ case EM_ALPHA:
+ return reloc_type == 0; /* R_ALPHA_NONE. */
+ case EM_PPC:
+ return reloc_type == 0; /* R_PPC_NONE. */
+ case EM_PPC64:
+ return reloc_type == 0; /* R_PPC64_NONE. */
+ case EM_ARM:
+ return reloc_type == 0; /* R_ARM_NONE. */
+ case EM_IA_64:
+ return reloc_type == 0; /* R_IA64_NONE. */
+ case EM_SH:
+ return reloc_type == 0; /* R_SH_NONE. */
+ case EM_S390_OLD:
+ case EM_S390:
+ return reloc_type == 0; /* R_390_NONE. */
+ case EM_CRIS:
+ return reloc_type == 0; /* R_CRIS_NONE. */
+ case EM_X86_64:
+ return reloc_type == 0; /* R_X86_64_NONE. */
+ case EM_MN10300:
+ return reloc_type == 0; /* R_MN10300_NONE. */
+ case EM_M32R:
+ return reloc_type == 0; /* R_M32R_NONE. */
+ }
+ return FALSE;
+}
+
/* Uncompresses a section that was compressed using zlib, in place.
* This is a copy of bfd_uncompress_section_contents, in bfd/compress.c */
@@ -8419,6 +8466,9 @@ debug_apply_relocations (void *file,
reloc_type = get_reloc_type (rp->r_info);
+ if (is_none_reloc (reloc_type))
+ continue;
+
if (is_32bit_abs_reloc (reloc_type)
|| is_32bit_pcrel_reloc (reloc_type))
reloc_size = 4;
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ld/testsuite/ld-elf/eh-group.exp 16 Sep 2008 13:28:54 -0000
@@ -0,0 +1,51 @@
+# Expect script for .eh_frame entries to a removed section.
+# Copyright 2008 Free Software Foundation, Inc.
+#
+# This file is part of the GNU Binutils.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+# MA 02110-1301, USA.
+#
+
+#
+# Written by Jan Kratochvil (jan.kratochvil@redhat.com)
+#
+# .eh_frame with relocations to a removed (group) section did result to:
+# error in tmpdir/eh-group.o(.eh_frame); no .eh_frame_hdr table will be created.
+# The purpose of this test is to merge two .o files with -r and then link this
+# merged file (containing a discarded R_X86_64_NONE relocation) to the final
+# executable trying to create .eh_frame_hdr. It needs a separate .exp file due
+# to the requirement of two `ld' runs.
+
+# Exclude non-ELF targets.
+
+if ![is_elf_format] {
+ return
+}
+
+set build_tests_ld {
+ {"Build eh-group1.o"
+ "-r" ""
+ {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"
+if [ld_simple_link $ld "tmpdir/eh-group" "-e _start tmpdir/eh-group.o"] {
+ pass $testname
+} else {
+ fail $testname
+}
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ld/testsuite/ld-elf/eh-group1.s 16 Sep 2008 13:28:54 -0000
@@ -0,0 +1,6 @@
+ .section sect, "axG", @progbits, sectgroup, comdat
+ .global _start
+_start:
+ .cfi_startproc
+ .skip 16
+ .cfi_endproc
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ ld/testsuite/ld-elf/eh-group2.s 16 Sep 2008 13:28:54 -0000
@@ -0,0 +1,4 @@
+ .section sect, "axG", @progbits, sectgroup, comdat
+ .cfi_startproc
+ .skip 16
+ .cfi_endproc