[binutils-gdb] PR23611, objcopy is not removing executable relocatable sections
Alan Modra
amodra@sourceware.org
Mon Sep 10 04:33:00 GMT 2018
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f9853190c8d90e9f7d43fae90478a0db291f9c03
commit f9853190c8d90e9f7d43fae90478a0db291f9c03
Author: Alan Modra <amodra@gmail.com>
Date: Mon Sep 10 11:57:08 2018 +0930
PR23611, objcopy is not removing executable relocatable sections
BFD handles ELF relocation sections in an executable differently to
relocation sections in a relocatable object. For a relocatable
object, BFD carries the relocations as data associated with the
section to which they apply; The relocation section doesn't appear as
a separate section. For an executable, dynamic relocation sections do
appear as separate sections. This means that objcopy needs to use
different strategies when dealing with relocations.
When --remove-relocations was added to objcopy with commit
d3e5f6c8f1e, objcopy lost the ability to remove dynamic relocation
sections such as .rela.plt from executables using the option
"--remove-section=.rela.plt". This patch reinstates that
functionality.
I thought it best to keep --remove-relocations as is, rather than
extending to handle dynamic relocations as per the patch in the PR,
because executables linked with --emit-relocs may have both dynamic
and non-dynamic relocations. In that case --remove-relocataions=* is
useful to remove all the non-dynamic relocations.
PR binutils/23611
* objcopy.c (handle_remove_section_option): Consider .rela and
.rel sections for stripping directly as well as attached to the
associated section they relocate.
* doc/binutils.texi (remove-relocations): Specify that this
option removes non-dynamic relocation sections.
* testsuite/binutils-all/objcopy.exp
(objcopy_remove_relocations_from_executable): New test.
Diff:
---
binutils/ChangeLog | 17 ++++++++++++---
binutils/doc/binutils.texi | 13 +++++++-----
binutils/objcopy.c | 10 ++++-----
binutils/testsuite/binutils-all/objcopy.exp | 33 +++++++++++++++++++++++++++++
4 files changed, 59 insertions(+), 14 deletions(-)
diff --git a/binutils/ChangeLog b/binutils/ChangeLog
index c58d70e..d77b3ab 100644
--- a/binutils/ChangeLog
+++ b/binutils/ChangeLog
@@ -1,3 +1,14 @@
+2018-09-10 Alan Modra <amodra@gmail.com>
+
+ PR binutils/23611
+ * objcopy.c (handle_remove_section_option): Consider .rela and
+ .rel sections for stripping directly as well as attached to the
+ associated section they relocate.
+ * doc/binutils.texi (remove-relocations): Specify that this
+ option removes non-dynamic relocation sections.
+ * testsuite/binutils-all/objcopy.exp
+ (objcopy_remove_relocations_from_executable): New test.
+
2018-09-03 Nick Clifton <nickc@redhat.com>
* po/ja.po: Updated Japanese translation.
@@ -234,8 +245,8 @@
2018-08-08 Kevin Buettner <kevinb@redhat.com>
- * dwarf.c (decode_location_expresion): Add case for
- DW_OP_GNU_variable_value.
+ * dwarf.c (decode_location_expresion): Add case for
+ DW_OP_GNU_variable_value.
2018-08-06 Claudiu Zissulescu <claziss@synopsys.com>
@@ -914,7 +925,7 @@
2018-02-19 Matthias Klose <doko@debian.org>
* strings.c (long_options): Include-all-whitespace does not take
- an extra agument.
+ an extra agument.
2018-02-13 Alan Modra <amodra@gmail.com>
diff --git a/binutils/doc/binutils.texi b/binutils/doc/binutils.texi
index e40ccb0..76cbed0 100644
--- a/binutils/doc/binutils.texi
+++ b/binutils/doc/binutils.texi
@@ -1321,17 +1321,20 @@ will remove all sections matching the pattern '.text.*', but will not
remove the section '.text.foo'.
@item --remove-relocations=@var{sectionpattern}
-Remove relocations from the output file for any section matching
-@var{sectionpattern}. This option may be given more than once. Note
-that using this option inappropriately may make the output file
-unusable. Wildcard characters are accepted in @var{sectionpattern}.
+Remove non-dynamic relocations from the output file for any section
+matching @var{sectionpattern}. This option may be given more than
+once. Note that using this option inappropriately may make the output
+file unusable, and attempting to remove a dynamic relocation section
+such as @samp{.rela.plt} from an executable or shared library with
+@option{--remove-relocations=.plt} will not work. Wildcard characters
+are accepted in @var{sectionpattern}.
For example:
@smallexample
--remove-relocations=.text.*
@end smallexample
-will remove the relocations for all sections matching the patter
+will remove the relocations for all sections matching the pattern
'.text.*'.
If the first character of @var{sectionpattern} is the exclamation
diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index 6bd9339..f712ffe 100644
--- a/binutils/objcopy.c
+++ b/binutils/objcopy.c
@@ -3943,7 +3943,7 @@ discard_relocations (bfd *ibfd ATTRIBUTE_UNUSED, asection *isection)
/* Wrapper for dealing with --remove-section (-R) command line arguments.
A special case is detected here, if the user asks to remove a relocation
section (one starting with ".rela." or ".rel.") then this removal must
- be done using a different technique. */
+ be done using a different technique in a relocatable object. */
static void
handle_remove_section_option (const char *section_pattern)
@@ -3952,11 +3952,9 @@ handle_remove_section_option (const char *section_pattern)
handle_remove_relocations_option (section_pattern + 5);
else if (strncmp (section_pattern, ".rel.", 5) == 0)
handle_remove_relocations_option (section_pattern + 4);
- else
- {
- find_section_list (section_pattern, TRUE, SECTION_CONTEXT_REMOVE);
- sections_removed = TRUE;
- }
+
+ find_section_list (section_pattern, TRUE, SECTION_CONTEXT_REMOVE);
+ sections_removed = TRUE;
}
/* Copy relocations in input section ISECTION of IBFD to an output
diff --git a/binutils/testsuite/binutils-all/objcopy.exp b/binutils/testsuite/binutils-all/objcopy.exp
index d979648..61793d9 100644
--- a/binutils/testsuite/binutils-all/objcopy.exp
+++ b/binutils/testsuite/binutils-all/objcopy.exp
@@ -1223,3 +1223,36 @@ proc objcopy_test_without_global_symbol { } {
setup_xfail aarch64*-*-* arm*-*-*
objcopy_test_without_global_symbol
+
+# objcopy remove relocation from executable test
+
+proc objcopy_remove_relocations_from_executable { } {
+ global OBJCOPY
+ global srcdir
+ global subdir
+ global READELF
+
+ set test "remove-section relocation sections"
+
+ if { [target_compile $srcdir/$subdir/testprog.c tmpdir/pr23611 executable debug] != "" } {
+ untested $test
+ return
+ }
+
+ if [is_remote host] {
+ set objfile [remote_download host tmpdir/pr23611]
+ } else {
+ set objfile tmpdir/pr23611
+ }
+ set out tmpdir/pr23611.out
+
+ set exec_output1 [binutils_run $OBJCOPY "-R .rela.plt -R .rela.dyn -R .rel.plt -R .rel.dyn $objfile $out"]
+ set exec_output2 [binutils_run $READELF "-S $out"]
+ if { [string match "*.rel.plt*" $exec_output2] || [string match "*.rela.plt*" $exec_output2] || [string match "*.rel.dyn*" $exec_output2] || [string match "*.rela.dyn*" $exec_output2] } {
+ fail $test
+ return
+ }
+ pass $test
+}
+
+objcopy_remove_relocations_from_executable
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