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authorRahul Chaudhry <rahulchaudhry@google.com>2016-10-21 23:34:06 (GMT)
committerRahul Chaudhry <rahulchaudhry@google.com>2016-10-21 23:34:06 (GMT)
commitb8ff982870858c54e09105458b6955b391cc0a11 (patch)
tree4257a2c773e6288a8638f105a4ed21ccc45ff4ec /binutils-2.25/gold/icf.cc
parent129dec3ed0e1fc07f75a4322014d770cfd642f4d (diff)
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gold: make icf respect section alignment requirements.refs/keep-around/b8ff982870858c54e09105458b6955b391cc0a11
Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=628795 The upstream bug is https://sourceware.org/bugzilla/show_bug.cgi?id=17704 This patch is backported from upstream - commit ac423761af22f7858a1413cda5df3e1d5e88d4e4 Author: Gergely Nagy <ngg@tresorit.com> Date: Fri Oct 21 11:08:20 2016 -0700 Fix PR 17704. This fix keeps the section with the highest alignment when folding sections with ICF. 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.
Diffstat (limited to 'binutils-2.25/gold/icf.cc')
-rw-r--r--binutils-2.25/gold/icf.cc55
1 files changed, 45 insertions, 10 deletions
diff --git a/binutils-2.25/gold/icf.cc b/binutils-2.25/gold/icf.cc
index 1ae1829..d841298 100644
--- a/binutils-2.25/gold/icf.cc
+++ b/binutils-2.25/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,
- &section_contents);
+ this->id_section_, section_addraligns,
+ &is_secn_or_group_unique, &section_contents);
}
if (parameters->options().print_icf_sections())