| 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. |
| |
| diff --git a/gold/icf.cc b/gold/icf.cc |
| index dce0b8b3e2..c09c746ae1 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()) |