unstrip: Also check sh_size in compare_unalloc_sections.

compare_unalloc_sections only checked sh_flags and the section names.
This would cause stripped/debug section mismatches when there were
multiple sections with the same name and flags. Fix this by also checking
the size of the section matches.

Add a testcase that has two ".group" sections created on i386 with the
gcc annobin plugin.

Signed-off-by: Mark Wielaard <[email protected]>

src/ChangeLog

@@ -1,3 +1,7 @@
+2018-07-24  Mark Wielaard  <[email protected]>
+
+	* unstrip.c (compare_unalloc_sections): Also compare sh_size.
+
 2018-07-21  Mark Wielaard  <[email protected]>
 
 	* unstrip.c (adjust_all_relocs): Skip SHT_GROUP sections.

src/unstrip.c

@@ -709,6 +709,12 @@ compare_unalloc_sections (const GElf_Shdr *shdr1, const GElf_Shdr *shdr2,
   if (shdr1->sh_flags > shdr2->sh_flags)
     return 1;
 
+  /* Sizes should be the same.  */
+  if (shdr1->sh_size < shdr2->sh_size)
+    return -1;
+  if (shdr1->sh_size > shdr2->sh_size)
+    return 1;
+
   /* Sort by name as last resort.  */
   return strcmp (name1, name2);
 }

tests/ChangeLog

@@ -1,3 +1,9 @@
+2018-07-24  Mark Wielaard  <[email protected]>
+
+	* run-annobingroup.sh: Add testfile-annobingroup-i386.o tests.
+	* testfile-annobingroup-i386.o.bz2: New test file.
+	* Makefile.am (EXTRA_DIST): Add testfile-annobingroup-i386.o.bz2.
+
 2018-07-21  Mark Wielaard  <[email protected]>
 
 	* run-annobingroup.sh: New test.

tests/Makefile.am

@@ -195,6 +195,7 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh run-ar.sh \
 	     run-strip-test12.sh \
 	     run-strip-nothing.sh run-strip-remove-keep.sh run-strip-g.sh \
 	     run-annobingroup.sh testfile-annobingroup.o.bz2 \
+	     testfile-annobingroup-i386.o.bz2 \
 	     run-strip-strmerge.sh run-strip-nobitsalign.sh \
 	     testfile-nobitsalign.bz2 testfile-nobitsalign.strip.bz2 \
 	     run-strip-reloc.sh hello_i386.ko.bz2 hello_x86_64.ko.bz2 \

tests/run-annobingroup.sh

@@ -65,4 +65,59 @@ EOF
 
 testrun ${abs_top_builddir}/src/elfcmp testfile-annobingroup.o remerged.elf
 
+# echo "void * __attribute__((cold)) foo (void) { return foo; }"
+#      > testfile-annobingroup-i386.c
+# gcc -fpic -g -O2 -fplugin=annobin -c testfile-annobingroup-i386.c
+testfiles testfile-annobingroup-i386.o
+
+testrun_compare ${abs_top_builddir}/src/readelf -g testfile-annobingroup-i386.o << EOF
+
+Section group [ 1] '.group' with signature '.text.unlikely.group' contains 3 entries:
+  [ 8] .gnu.build.attributes..text.unlikely
+  [ 9] .rel.gnu.build.attributes..text.unlikely
+  [10] .text.unlikely
+
+COMDAT section group [ 2] '.group' with signature '__x86.get_pc_thunk.ax' contains 1 entry:
+  [13] .text.__x86.get_pc_thunk.ax
+EOF
+
+testrun ${abs_top_builddir}/src/strip -o stripped.elf -f debugfile.elf testfile-annobingroup-i386.o
+
+testrun_compare ${abs_top_builddir}/src/readelf -g stripped.elf << EOF
+
+Section group [ 1] '.group' with signature '.text.unlikely.group' contains 3 entries:
+  [ 8] .gnu.build.attributes..text.unlikely
+  [ 9] .rel.gnu.build.attributes..text.unlikely
+  [10] .text.unlikely
+
+COMDAT section group [ 2] '.group' with signature '__x86.get_pc_thunk.ax' contains 1 entry:
+  [13] .text.__x86.get_pc_thunk.ax
+EOF
+
+testrun_compare ${abs_top_builddir}/src/readelf -g debugfile.elf << EOF
+
+Section group [ 1] '.group' with signature '.text.unlikely.group' contains 3 entries:
+  [ 8] .gnu.build.attributes..text.unlikely
+  [ 9] .rel.gnu.build.attributes..text.unlikely
+  [10] .text.unlikely
+
+COMDAT section group [ 2] '.group' with signature '__x86.get_pc_thunk.ax' contains 1 entry:
+  [13] .text.__x86.get_pc_thunk.ax
+EOF
+
+testrun ${abs_top_builddir}/src/unstrip -o remerged.elf stripped.elf debugfile.elf
+
+testrun_compare ${abs_top_builddir}/src/readelf -g remerged.elf << EOF
+
+Section group [ 1] '.group' with signature '.text.unlikely.group' contains 3 entries:
+  [ 8] .gnu.build.attributes..text.unlikely
+  [ 9] .rel.gnu.build.attributes..text.unlikely
+  [10] .text.unlikely
+
+COMDAT section group [ 2] '.group' with signature '__x86.get_pc_thunk.ax' contains 1 entry:
+  [13] .text.__x86.get_pc_thunk.ax
+EOF
+
+testrun ${abs_top_builddir}/src/elfcmp testfile-annobingroup-i386.o remerged.elf
+
 exit 0