From c6ac678db54ed727cb673a87beeb7a41bdf13182 Mon Sep 17 00:00:00 2001 From: Sriraman Tallam Date: Thu, 24 Jan 2013 18:49:55 +0000 Subject: [PATCH] Default text reordering fix with a flag to turn it off. 2013-01-24 Sriraman Tallam * layout.cc (Layout::layout): Check for option text_reorder. (Layout::make_output_section): Ditto. * options.h (text_reorder): New option. * output.cc (Input_section_sort_compare): Remove special ordering of section names. (Output_section:: Input_section_sort_section_name_special_ordering_compare:: operator()): New function. (Output_section::sort_attached_input_sections): Use new sort function for .text. * output.h (Input_section_sort_section_name_special_ordering_compare): New struct. * testsuite/Makefile.am (text_section_grouping): Test option --no-text-reorder * testsuite/Makefile.in: Regenerate. * testsuite/text_section_grouping.sh: Check order of functions without default text reordering. --- gold/ChangeLog | 20 ++++++++++ gold/layout.cc | 6 ++- gold/options.h | 5 +++ gold/output.cc | 52 ++++++++++++++++++------- gold/output.h | 9 +++++ gold/testsuite/Makefile.am | 10 +++-- gold/testsuite/Makefile.in | 8 +++- gold/testsuite/text_section_grouping.sh | 8 ++++ 8 files changed, 99 insertions(+), 19 deletions(-) diff --git a/gold/ChangeLog b/gold/ChangeLog index 8e70fddc6ff..bcf8c06be05 100644 --- a/gold/ChangeLog +++ b/gold/ChangeLog @@ -1,3 +1,23 @@ +2013-01-24 Sriraman Tallam + + * layout.cc (Layout::layout): Check for option text_reorder. + (Layout::make_output_section): Ditto. + * options.h (text_reorder): New option. + * output.cc (Input_section_sort_compare): Remove special ordering + of section names. + (Output_section:: + Input_section_sort_section_name_special_ordering_compare:: + operator()): New function. + (Output_section::sort_attached_input_sections): Use new sort function + for .text. + * output.h (Input_section_sort_section_name_special_ordering_compare): + New struct. + * testsuite/Makefile.am (text_section_grouping): Test option + --no-text-reorder + * testsuite/Makefile.in: Regenerate. + * testsuite/text_section_grouping.sh: Check order of functions without + default text reordering. + 2013-01-18 Mike Frysinger * options.h (General_options): Change default to true for new_dtags. diff --git a/gold/layout.cc b/gold/layout.cc index 250782a92be..1eb2cc018d3 100644 --- a/gold/layout.cc +++ b/gold/layout.cc @@ -1149,7 +1149,8 @@ Layout::layout(Sized_relobj_file* object, unsigned int shndx, // By default the GNU linker sorts some special text sections ahead // of others. We are compatible. - if (!this->script_options_->saw_sections_clause() + if (parameters->options().text_reorder() + && !this->script_options_->saw_sections_clause() && !this->is_section_ordering_specified() && !parameters->options().relocatable() && Layout::special_ordering_of_input_section(name) >= 0) @@ -1646,7 +1647,8 @@ Layout::make_output_section(const char* name, elfcpp::Elf_Word type, // sections before other .text sections. We are compatible. We // need to know that this might happen before we attach any input // sections. - if (!this->script_options_->saw_sections_clause() + if (parameters->options().text_reorder() + && !this->script_options_->saw_sections_clause() && !this->is_section_ordering_specified() && !parameters->options().relocatable() && strcmp(name, ".text") == 0) diff --git a/gold/options.h b/gold/options.h index 9e65e8d878d..c138fa26e26 100644 --- a/gold/options.h +++ b/gold/options.h @@ -878,6 +878,11 @@ class General_options DEFINE_dirlist(library_path, options::TWO_DASHES, 'L', N_("Add directory to search path"), N_("DIR")); + DEFINE_bool(text_reorder, options::TWO_DASHES, '\0', true, + N_("Enable text section reordering for GCC section names " + "(default)"), + N_("Disable text section reordering for GCC section names")); + DEFINE_bool(nostdlib, options::ONE_DASH, '\0', false, N_(" Only search directories specified on the command line."), NULL); diff --git a/gold/output.cc b/gold/output.cc index 01126a3d7d1..22c0bf02b56 100644 --- a/gold/output.cc +++ b/gold/output.cc @@ -3389,19 +3389,6 @@ Output_section::Input_section_sort_compare::operator()( return s1.index() < s2.index(); } - // Some input section names have special ordering requirements. - int o1 = Layout::special_ordering_of_input_section(s1.section_name().c_str()); - int o2 = Layout::special_ordering_of_input_section(s2.section_name().c_str()); - if (o1 != o2) - { - if (o1 < 0) - return false; - else if (o2 < 0) - return true; - else - return o1 < o2; - } - // A section with a priority follows a section without a priority. bool s1_has_priority = s1.has_priority(); bool s2_has_priority = s2.has_priority(); @@ -3508,6 +3495,42 @@ Output_section::Input_section_sort_section_order_index_compare::operator()( return s1_secn_index < s2_secn_index; } +// Return true if S1 should come before S2. This is the sort comparison +// function for .text to sort sections with prefixes +// .text.{unlikely,exit,startup,hot} before other sections. +bool +Output_section::Input_section_sort_section_name_special_ordering_compare + ::operator()( + const Output_section::Input_section_sort_entry& s1, + const Output_section::Input_section_sort_entry& s2) const +{ + // We sort all the sections with no names to the end. + if (!s1.section_has_name() || !s2.section_has_name()) + { + if (s1.section_has_name()) + return true; + if (s2.section_has_name()) + return false; + return s1.index() < s2.index(); + } + + // Some input section names have special ordering requirements. + int o1 = Layout::special_ordering_of_input_section(s1.section_name().c_str()); + int o2 = Layout::special_ordering_of_input_section(s2.section_name().c_str()); + if (o1 != o2) + { + if (o1 < 0) + return false; + else if (o2 < 0) + return true; + else + return o1 < o2; + } + + // Keep input order otherwise. + return s1.index() < s2.index(); +} + // This updates the section order index of input sections according to the // the order specified in the mapping from Section id to order index. @@ -3576,6 +3599,9 @@ Output_section::sort_attached_input_sections() || this->type() == elfcpp::SHT_FINI_ARRAY) std::sort(sort_list.begin(), sort_list.end(), Input_section_sort_init_fini_compare()); + else if (strcmp(this->name(), ".text") == 0) + std::sort(sort_list.begin(), sort_list.end(), + Input_section_sort_section_name_special_ordering_compare()); else std::sort(sort_list.begin(), sort_list.end(), Input_section_sort_compare()); diff --git a/gold/output.h b/gold/output.h index 8f3943b0426..77222376e2e 100644 --- a/gold/output.h +++ b/gold/output.h @@ -4200,6 +4200,15 @@ class Output_section : public Output_data const Input_section_sort_entry&) const; }; + // This is the sort comparison function for .text to sort sections with + // prefixes .text.{unlikely,exit,startup,hot} before other sections. + struct Input_section_sort_section_name_special_ordering_compare + { + bool + operator()(const Input_section_sort_entry&, + const Input_section_sort_entry&) const; + }; + // Fill data. This is used to fill in data between input sections. // It is also used for data statements (BYTE, WORD, etc.) in linker // scripts. When we have to keep track of the input sections, we diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am index fa1161f3b50..499dba6508c 100644 --- a/gold/testsuite/Makefile.am +++ b/gold/testsuite/Makefile.am @@ -259,14 +259,18 @@ final_layout.stdout: final_layout $(TEST_NM) -n --synthetic final_layout > final_layout.stdout check_SCRIPTS += text_section_grouping.sh -check_DATA += text_section_grouping.stdout -MOSTLYCLEANFILES += text_section_grouping +check_DATA += text_section_grouping.stdout text_section_no_grouping.stdout +MOSTLYCLEANFILES += text_section_grouping text_section_no_grouping text_section_grouping.o: text_section_grouping.cc $(CXXCOMPILE) -O0 -c -ffunction-sections -g -o $@ $< text_section_grouping: text_section_grouping.o gcctestdir/ld $(CXXLINK) -Bgcctestdir/ text_section_grouping.o +text_section_no_grouping: text_section_grouping.o gcctestdir/ld + $(CXXLINK) -Bgcctestdir/ -Wl,--no-text-reorder text_section_grouping.o text_section_grouping.stdout: text_section_grouping - $(TEST_NM) -n --synthetic text_section_grouping > text_section_grouping.stdout + $(TEST_NM) -n --synthetic text_section_grouping > text_section_grouping.stdout +text_section_no_grouping.stdout: text_section_no_grouping + $(TEST_NM) -n --synthetic text_section_no_grouping > text_section_no_grouping.stdout check_PROGRAMS += icf_virtual_function_folding_test MOSTLYCLEANFILES += icf_virtual_function_folding_test icf_virtual_function_folding_test.map diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in index 51bdb271dc2..a8129f98376 100644 --- a/gold/testsuite/Makefile.in +++ b/gold/testsuite/Makefile.in @@ -113,6 +113,7 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_so_test_2.stdout \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ final_layout.stdout \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ text_section_grouping.stdout \ +@GCC_TRUE@@NATIVE_LINKER_TRUE@ text_section_no_grouping.stdout \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_preemptible_functions_test.stdout \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_string_merge_test.stdout \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_sht_rel_addend_test.stdout \ @@ -128,6 +129,7 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ final_layout_sequence.txt \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ final_layout_script.lds \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ text_section_grouping \ +@GCC_TRUE@@NATIVE_LINKER_TRUE@ text_section_no_grouping \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_virtual_function_folding_test \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_virtual_function_folding_test.map \ @GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_preemptible_functions_test \ @@ -4376,8 +4378,12 @@ uninstall-am: @GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXCOMPILE) -O0 -c -ffunction-sections -g -o $@ $< @GCC_TRUE@@NATIVE_LINKER_TRUE@text_section_grouping: text_section_grouping.o gcctestdir/ld @GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXLINK) -Bgcctestdir/ text_section_grouping.o +@GCC_TRUE@@NATIVE_LINKER_TRUE@text_section_no_grouping: text_section_grouping.o gcctestdir/ld +@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXLINK) -Bgcctestdir/ -Wl,--no-text-reorder text_section_grouping.o @GCC_TRUE@@NATIVE_LINKER_TRUE@text_section_grouping.stdout: text_section_grouping -@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_NM) -n --synthetic text_section_grouping > text_section_grouping.stdout +@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_NM) -n --synthetic text_section_grouping > text_section_grouping.stdout +@GCC_TRUE@@NATIVE_LINKER_TRUE@text_section_no_grouping.stdout: text_section_no_grouping +@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_NM) -n --synthetic text_section_no_grouping > text_section_no_grouping.stdout @GCC_TRUE@@NATIVE_LINKER_TRUE@icf_virtual_function_folding_test.o: icf_virtual_function_folding_test.cc @GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXCOMPILE) -O0 -c -ffunction-sections -fPIE -g -o $@ $< @GCC_TRUE@@NATIVE_LINKER_TRUE@icf_virtual_function_folding_test: icf_virtual_function_folding_test.o gcctestdir/ld diff --git a/gold/testsuite/text_section_grouping.sh b/gold/testsuite/text_section_grouping.sh index a79836ca0c3..84ebe4c9ab3 100755 --- a/gold/testsuite/text_section_grouping.sh +++ b/gold/testsuite/text_section_grouping.sh @@ -26,6 +26,8 @@ # according to prefix. .text.unlikely, .text.startup and .text.hot should # be grouped and placed together. +# Also check if the functions do not get grouped with option --no-text-reorder. + set -e check() @@ -63,3 +65,9 @@ check text_section_grouping.stdout "unlikely_bar" "startup_bar" check text_section_grouping.stdout "startup_bar" "hot_bar" check text_section_grouping.stdout "unlikely_foo" "startup_bar" check text_section_grouping.stdout "startup_foo" "hot_bar" + +check text_section_no_grouping.stdout "hot_foo" "startup_foo" +check text_section_no_grouping.stdout "startup_foo" "unlikely_foo" +check text_section_no_grouping.stdout "unlikely_foo" "hot_bar" +check text_section_no_grouping.stdout "hot_bar" "startup_bar" +check text_section_no_grouping.stdout "startup_bar" "unlikely_bar" -- 2.30.2