[PATCH] PR gold/17704
Sriraman Tallam
tmsriram@google.com
Thu Aug 18 19:14:00 GMT 2016
On Fri, Aug 12, 2016 at 8:33 AM, Cary Coutant <ccoutant@gmail.com> wrote:
>>> PR gold/17704
>>> * icf.cc (match_sections): Add new parameter section_addraligns.
>>> Check section alignment and keep the section with the strictest
>>> alignment.
>>> (find_identical_sections): New local variable section_addraligns.
>>> Store each section's alignment.
>>> * testsuite/pr17704a_test.s: New file.
>>> * testsuite/Makefile.am (pr17704a_test): New test.
>>> * testsuite/Makefile.in: Regenerate.
>
> + (void)section_addraligns;
>
> This shouldn't be necessary, but if it really is, I'd prefer to use
> ATTRIBUTE_UNUSED on the parameter.
>
> Also, I get this when trying to apply the patch:
>
> patch: **** malformed patch at line 146: diff --git
> a/gold/testsuite/pr17704a_test.s b/gold/testsuite/pr17704a_test.s
>
> I think you may have deleted too much when deleting the hunks for
> testsuite/Makefile.in.
Sorry for the late response, fixed both problems. Patch attached.
Thanks
Sri
>
> -cary
-------------- next part --------------
PR gold/17704
* icf.cc (match_sections): Add new parameter section_addraligns.
Check section alignment and keep the section with the strictest
alignment.
(find_identical_sections): New local variable section_addraligns.
Store each section's alignment.
* testsuite/pr17704a_test.S: New file.
* testsuite/Makefile.am (pr17704a_test): New test.
* testsuite/Makefile.in: Regenerate.
diff --git a/gold/icf.cc b/gold/icf.cc
index dce0b8b..597e19a 100644
--- a/gold/icf.cc
+++ b/gold/icf.cc
@@ -590,6 +590,7 @@ match_sections(unsigned int iteration_num,
std::vector<unsigned int>* num_tracked_relocs,
std::vector<unsigned int>* kept_section_id,
const std::vector<Section_id>& id_section,
+ const std::vector<uint64_t>& section_addraligns,
std::vector<bool>* is_secn_or_group_unique,
std::vector<std::string>* section_contents)
{
@@ -630,13 +631,7 @@ match_sections(unsigned int iteration_num,
{
if ((*kept_section_id)[i] != i)
{
- // This section is already folded into something. See
- // if it should point to a different kept section.
- unsigned int kept_section = (*kept_section_id)[i];
- if (kept_section != (*kept_section_id)[kept_section])
- {
- (*kept_section_id)[i] = (*kept_section_id)[kept_section];
- }
+ // This section is already folded into something.
continue;
}
this_secn_contents = get_section_contents(false, secn, i, NULL,
@@ -671,7 +666,25 @@ match_sections(unsigned int iteration_num,
this_secn_contents.c_str(),
this_secn_contents.length()) != 0)
continue;
- (*kept_section_id)[i] = kept_section;
+
+ // Check section alignment here.
+ // The section with the larger alignment requirement
+ // should be kept. We assume alignment can only be
+ // zero or postive integral powers of two.
+ uint64_t align_i = section_addraligns[i];
+ uint64_t align_kept = section_addraligns[kept_section];
+ if (align_i <= align_kept)
+ {
+ (*kept_section_id)[i] = kept_section;
+ }
+ else
+ {
+ (*kept_section_id)[kept_section] = i;
+ it->second = i;
+ full_section_contents[kept_section].swap(
+ full_section_contents[i]);
+ }
+
converged = false;
break;
}
@@ -688,6 +701,26 @@ match_sections(unsigned int iteration_num,
(*is_secn_or_group_unique)[i] = true;
}
+ // If a section was folded into another section that was later folded
+ // again then the former has to be updated.
+ for (unsigned int i = 0; i < id_section.size(); i++)
+ {
+ // Find the end of the folding chain
+ unsigned int kept = i;
+ while ((*kept_section_id)[kept] != kept)
+ {
+ kept = (*kept_section_id)[kept];
+ }
+ // Update every element of the chain
+ unsigned int current = i;
+ while ((*kept_section_id)[current] != kept)
+ {
+ unsigned int next = (*kept_section_id)[current];
+ (*kept_section_id)[current] = kept;
+ current = next;
+ }
+ }
+
return converged;
}
@@ -719,6 +752,7 @@ Icf::find_identical_sections(const Input_objects* input_objects,
{
unsigned int section_num = 0;
std::vector<unsigned int> num_tracked_relocs;
+ std::vector<uint64_t> section_addraligns;
std::vector<bool> is_secn_or_group_unique;
std::vector<std::string> section_contents;
const Target& target = parameters->target();
@@ -759,6 +793,7 @@ Icf::find_identical_sections(const Input_objects* input_objects,
this->section_id_[Section_id(*p, i)] = section_num;
this->kept_section_id_.push_back(section_num);
num_tracked_relocs.push_back(0);
+ section_addraligns.push_back((*p)->section_addralign(i));
is_secn_or_group_unique.push_back(false);
section_contents.push_back("");
section_num++;
@@ -779,8 +814,8 @@ Icf::find_identical_sections(const Input_objects* input_objects,
num_iterations++;
converged = match_sections(num_iterations, symtab,
&num_tracked_relocs, &this->kept_section_id_,
- this->id_section_, &is_secn_or_group_unique,
- §ion_contents);
+ this->id_section_, section_addraligns,
+ &is_secn_or_group_unique, §ion_contents);
}
if (parameters->options().print_icf_sections())
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index c8d3093..8b8fa81 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -1131,6 +1131,12 @@ x86_64_overflow_pc32.err: x86_64_overflow_pc32.o gcctestdir/ld
exit 1; \
fi
+check_PROGRAMS += pr17704a_test
+pr17704a_test.o: pr17704a_test.s
+ $(TEST_AS) --64 -o $@ $<
+pr17704a_test: pr17704a_test.o gcctestdir/ld
+ gcctestdir/ld --icf=all -o $@ $<
+
check_SCRIPTS += x32_overflow_pc32.sh
check_DATA += x32_overflow_pc32.err
MOSTLYCLEANFILES += x32_overflow_pc32.err
diff --git a/gold/testsuite/pr17704a_test.s b/gold/testsuite/pr17704a_test.s
index e69de29..2b39e64 100644
--- a/gold/testsuite/pr17704a_test.s
+++ b/gold/testsuite/pr17704a_test.s
@@ -0,0 +1,23 @@
+nop
+ .section .text.foo,"axG",@progbits,foo,comdat
+foo:
+ ret
+
+ .section .text.bar,"axG",@progbits,bar,comdat
+ .align 2
+bar:
+ ret
+
+ .section .text._start,"ax",@progbits
+ .globl _start
+_start:
+ leaq bar(%rip), %rsi
+ testb $1, %sil
+ je .L9
+ mov $1, %eax
+ mov $1, %ebx
+ int $0x80
+.L9:
+ mov $1, %eax
+ mov $0, %ebx
+ int $0x80
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