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[binutils-gdb] MIPS/BFD: Fix section symbol name fetching in relocation
- From: Maciej W.Rozycki <macro at sourceware dot org>
- To: bfd-cvs at sourceware dot org
- Date: 27 May 2016 21:34:04 -0000
- Subject: [binutils-gdb] MIPS/BFD: Fix section symbol name fetching in relocation
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ceab86af75e9870ecf2da772a0d867ca12521a24
commit ceab86af75e9870ecf2da772a0d867ca12521a24
Author: Maciej W. Rozycki <macro@imgtec.com>
Date: Fri May 27 20:41:40 2016 +0100
MIPS/BFD: Fix section symbol name fetching in relocation
Symbol table entries for section symbols are different between IRIX and
traditional MIPS ELF targets in that IRIX entries have their `st_name'
member pointing at the section's name in the string table section, while
traditional entries have 0 there and the section header string table has
to be referred via the relevant section header's `shn_name' member
instead.
This is chosen with the `elf_backend_name_local_section_symbols' backend
and can be observed with `readelf -s' output for an IRIX object:
Symbol table '.symtab' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 SECTION LOCAL DEFAULT 1 .text
2: 00000000 0 SECTION LOCAL DEFAULT 3 .data
3: 00000000 0 SECTION LOCAL DEFAULT 4 .bss
4: 00000000 0 SECTION LOCAL DEFAULT 5 .reginfo
5: 00000000 0 SECTION LOCAL DEFAULT 6 .MIPS.abiflags
6: 00000000 0 SECTION LOCAL DEFAULT 7 .pdr
7: 00000000 0 SECTION LOCAL DEFAULT 9 .gnu.attributes
8: 00002000 16 FUNC GLOBAL DEFAULT 1 foo
9: 00004008 0 FUNC LOCAL DEFAULT 1 abar
10: 00002008 0 FUNC LOCAL DEFAULT 1 afoo
11: 00004000 16 FUNC GLOBAL DEFAULT 1 bar
and a corresponding traditional object:
Symbol table '.symtab' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 SECTION LOCAL DEFAULT 1
2: 00000000 0 SECTION LOCAL DEFAULT 3
3: 00000000 0 SECTION LOCAL DEFAULT 4
4: 00004008 0 FUNC LOCAL DEFAULT 1 abar
5: 00002008 0 FUNC LOCAL DEFAULT 1 afoo
6: 00000000 0 SECTION LOCAL DEFAULT 5
7: 00000000 0 SECTION LOCAL DEFAULT 6
8: 00000000 0 SECTION LOCAL DEFAULT 7
9: 00000000 0 SECTION LOCAL DEFAULT 9
10: 00002000 16 FUNC GLOBAL DEFAULT 1 foo
11: 00004000 16 FUNC GLOBAL DEFAULT 1 bar
respectively. Consequently the right way to retrieve a section symbol's
name has to be chosen in `mips_elf_calculate_relocation' for the purpose
of error reporting.
Originally we produced symbol tables in the traditional object format
only and we handled it correctly until it was lost in a rewrite with:
commit 7403cb6305f5660fccc8869d3333a731102ae978
Author: Mark Mitchell <mark@codesourcery.com>
Date: Wed Jun 30 20:13:43 1999 +0000
probably because of the extra pointer indirection added which made the
same expression have a different meaning.
With the addition of IRIX symbol table format with:
commit 174fd7f9556183397625dbfa99ef68ecd325c74b
Author: Richard Sandiford <rdsandiford@googlemail.com>
Date: Mon Feb 9 08:04:00 2004 +0000
the bug has been partially covered and now when a relocation error is
triggered with an IRIX object the offending section symbol is correctly
reported:
tmpdir/dump0.o: In function `foo':
(.text+0x2000): relocation truncated to fit: R_MIPS_26 against `.text'
tmpdir/dump0.o: In function `bar':
(.text+0x4000): relocation truncated to fit: R_MIPS_26 against `.text'
because `bfd_elf_string_from_elf_section' retrieves the name from the
string table section. With a traditional object however the function
returns an empty string and consequently `no symbol' is printed instead:
tmpdir/dump0.o: In function `foo':
(.text+0x2000): relocation truncated to fit: R_MIPS_26 against `no symbol'
tmpdir/dump0.o: In function `bar':
(.text+0x4000): relocation truncated to fit: R_MIPS_26 against `no symbol'
Restore the original semantics so that the section name is always
correctly retrieved.
bfd/
* elfxx-mips.c (mips_elf_calculate_relocation): Also use the
section name if `bfd_elf_string_from_elf_section' returns an
empty string.
ld/
* testsuite/ld-mips-elf/reloc-local-overflow.d: New test.
* testsuite/ld-mips-elf/reloc-local-overflow.s: Source for the
new test.
* testsuite/ld-mips-elf/mips-elf.exp: Run the new test.
Diff:
---
bfd/ChangeLog | 6 ++++++
bfd/elfxx-mips.c | 2 +-
ld/ChangeLog | 7 +++++++
ld/testsuite/ld-mips-elf/mips-elf.exp | 2 ++
ld/testsuite/ld-mips-elf/reloc-local-overflow.d | 7 +++++++
ld/testsuite/ld-mips-elf/reloc-local-overflow.s | 8 ++++++++
6 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index bb9cb3c..5bace1e 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2016-05-27 Maciej W. Rozycki <macro@imgtec.com>
+
+ * elfxx-mips.c (mips_elf_calculate_relocation): Also use the
+ section name if `bfd_elf_string_from_elf_section' returns an
+ empty string.
+
2016-05-26 Maciej W. Rozycki <macro@imgtec.com>
* elfxx-mips.c (_bfd_mips_elf_relocate_section)
diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
index 3e7b488..2fff306 100644
--- a/bfd/elfxx-mips.c
+++ b/bfd/elfxx-mips.c
@@ -5322,7 +5322,7 @@ mips_elf_calculate_relocation (bfd *abfd, bfd *input_bfd,
*namep = bfd_elf_string_from_elf_section (input_bfd,
symtab_hdr->sh_link,
sym->st_name);
- if (*namep == '\0')
+ if (*namep == NULL || **namep == '\0')
*namep = bfd_section_name (input_bfd, sec);
target_is_16_bit_code_p = ELF_ST_IS_MIPS16 (sym->st_other);
diff --git a/ld/ChangeLog b/ld/ChangeLog
index 4462450..1d683ac 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,10 @@
+2016-05-27 Maciej W. Rozycki <macro@imgtec.com>
+
+ * testsuite/ld-mips-elf/reloc-local-overflow.d: New test.
+ * testsuite/ld-mips-elf/reloc-local-overflow.s: Source for the
+ new test.
+ * testsuite/ld-mips-elf/mips-elf.exp: Run the new test.
+
2016-05-26 Maciej W. Rozycki <macro@imgtec.com>
* testsuite/ld-mips-elf/unaligned-jalx-0.d: Fold
diff --git a/ld/testsuite/ld-mips-elf/mips-elf.exp b/ld/testsuite/ld-mips-elf/mips-elf.exp
index f9bbcec..0c2a93b 100644
--- a/ld/testsuite/ld-mips-elf/mips-elf.exp
+++ b/ld/testsuite/ld-mips-elf/mips-elf.exp
@@ -440,6 +440,8 @@ if { $has_newabi } {
"reloc-6b"]]
}
+run_dump_test "reloc-local-overflow" [list [list ld $abi_ldflags(o32)]]
+
if {$has_newabi && $linux_gnu} {
run_dump_test "eh-frame1-n32"
run_dump_test "eh-frame1-n64"
diff --git a/ld/testsuite/ld-mips-elf/reloc-local-overflow.d b/ld/testsuite/ld-mips-elf/reloc-local-overflow.d
new file mode 100644
index 0000000..b5512ee
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/reloc-local-overflow.d
@@ -0,0 +1,7 @@
+#name: MIPS reloc against local symbol overflow
+#source: reloc-local-overflow.s
+#as: -EB -32
+#ld: -EB -Tdata 0x10000 -e 0
+#error: \A[^\n]*:\(\.data\+0x1000\): relocation truncated to fit: R_MIPS_16 against `\.data'\Z
+
+# Verify that the section name (`.data') is printed rather than `no symbol'.
diff --git a/ld/testsuite/ld-mips-elf/reloc-local-overflow.s b/ld/testsuite/ld-mips-elf/reloc-local-overflow.s
new file mode 100644
index 0000000..a07255c
--- /dev/null
+++ b/ld/testsuite/ld-mips-elf/reloc-local-overflow.s
@@ -0,0 +1,8 @@
+ .data
+ .space 0x1000
+
+ .align 2
+ .type bar, @object
+bar:
+ .half bar
+ .size bar, . - bar