Fix problem with ICF where diffs in EH frame info is ignored.

	PR gold/21066
	* gc.h (gc_process_relocs): Track relocations in .eh_frame sections
	when ICF is enabled, even though the .eh_frame sections themselves
	are not foldable.
	* icf.cc (get_section_contents): Change arguments to permit operation
	on just part of a section. Include extra identity regions in the
	referring section's contents recursively.
	(match_sections): Lock object here instead of in get_section_contents
	so that get_section_contents can operate recursively.
	(Icf::add_ehframe_links): New method.
	(Icf::find_identical_sections): Pass .eh_frame sections to
	add_ehframe_links(). Increase default iteration count from 2 to 3
	because handling exception info typically requires one extra iteration.
	* icf.h (Icf::extra_identity_list_): New data member with accessor.
	(is_section_foldable_candidate): Include .gcc_except_table sections.
	* options.h: Update documentation for new default ICF iteration count.
	* testsuite/Makefile.am (icf_test_pr21066): New test case.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/icf_test_pr21066.cc: New source file.
	* testsuite/icf_test_pr21066.sh: New test script.

4 files changed, 143 insertions, 1 deletions

diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index e499177..4c26f33 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -278,6 +278,16 @@ icf_test: icf_test.o gcctestdir/ld
 icf_test.map: icf_test
 	@touch icf_test.map
 
+check_SCRIPTS += icf_test_pr21066.sh
+check_DATA += icf_test_pr21066.map
+MOSTLYCLEANFILES += icf_test_pr21066 icf_test_pr21066.map
+icf_test_pr21066.o: icf_test_pr21066.cc
+	$(CXXCOMPILE) -O0 -c -ffunction-sections -g -o $@ $<
+icf_test_pr21066: icf_test_pr21066.o gcctestdir/ld
+	$(CXXLINK) -o icf_test_pr21066 -Bgcctestdir/ -Wl,--icf=all,-Map,icf_test_pr21066.map icf_test_pr21066.o
+icf_test_pr21066.map: icf_test_pr21066
+	@touch icf_test_pr21066.map
+
 check_SCRIPTS += icf_keep_unique_test.sh
 check_DATA += icf_keep_unique_test.stdout
 MOSTLYCLEANFILES += icf_keep_unique_test
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index a5b109b..dac0db2 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -129,7 +129,7 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	gc_orphan_section_test.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	pr14265.sh pr20717.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	gc_dynamic_list_test.sh \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_test.sh \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_test.sh icf_test_pr21066.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_keep_unique_test.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_safe_test.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_safe_pie_test.sh \
@@ -152,6 +152,7 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	pr14265.stdout pr20717.stdout \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	gc_dynamic_list_test.stdout \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_test.map \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_test_pr21066.map \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_keep_unique_test.stdout \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_safe_test_1.stdout \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_safe_test_2.stdout \
@@ -182,6 +183,8 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	gc_orphan_section_test pr14265 \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	pr20717 gc_dynamic_list_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_test icf_test.map \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_test_pr21066 \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_test_pr21066.map \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_keep_unique_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_safe_test icf_safe_test.map \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	icf_safe_pie_test \
@@ -2705,6 +2708,7 @@ pdfdir = @pdfdir@
 prefix = @prefix@
 program_transform_name = @program_transform_name@
 psdir = @psdir@
+runstatedir = @runstatedir@
 sbindir = @sbindir@
 sharedstatedir = @sharedstatedir@
 srcdir = @srcdir@
@@ -5517,6 +5521,13 @@ icf_test.sh.log: icf_test.sh
 	--log-file $$b.log --trs-file $$b.trs \
 	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
 	"$$tst" $(AM_TESTS_FD_REDIRECT)
+icf_test_pr21066.sh.log: icf_test_pr21066.sh
+	@p='icf_test_pr21066.sh'; \
+	b='icf_test_pr21066.sh'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
 icf_keep_unique_test.sh.log: icf_keep_unique_test.sh
 	@p='icf_keep_unique_test.sh'; \
 	b='icf_keep_unique_test.sh'; \
@@ -7935,6 +7946,12 @@ uninstall-am:
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXLINK) -o icf_test -Wl,--icf=all,-Map,icf_test.map icf_test.o
 @GCC_TRUE@@NATIVE_LINKER_TRUE@icf_test.map: icf_test
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	@touch icf_test.map
+@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_test_pr21066.o: icf_test_pr21066.cc
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXCOMPILE) -O0 -c -ffunction-sections -g -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_test_pr21066: icf_test_pr21066.o gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXLINK) -o icf_test_pr21066 -Bgcctestdir/ -Wl,--icf=all,-Map,icf_test_pr21066.map icf_test_pr21066.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_test_pr21066.map: icf_test_pr21066
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	@touch icf_test_pr21066.map
 @GCC_TRUE@@NATIVE_LINKER_TRUE@icf_keep_unique_test.o: icf_keep_unique_test.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXCOMPILE) -O0 -c -ffunction-sections -g -o $@ $<
 @GCC_TRUE@@NATIVE_LINKER_TRUE@icf_keep_unique_test: icf_keep_unique_test.o gcctestdir/ld
diff --git a/gold/testsuite/icf_test_pr21066.cc b/gold/testsuite/icf_test_pr21066.cc
new file mode 100644
index 0000000..568873d
--- /dev/null
+++ b/gold/testsuite/icf_test_pr21066.cc
@@ -0,0 +1,67 @@
+// icf_test.cc -- a test case for gold
+
+// Copyright (C) 2009-2018 Free Software Foundation, Inc.
+// Test case from PR 21066 submitted by Gandhi Shaheen
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
+// The goal of this program is to verify if identical code folding
+// correctly identifies and folds functions.  folded_func must be
+// folded into kept_func.
+
+// Written by Sriraman Tallam <tmsriram@google.com>.
+
+#include <stdio.h>
+
+struct first_exception {
+};
+
+struct second_exception {
+};
+
+typedef void (*callback_fn_t)();
+
+void raise_first_exception()
+{
+  throw first_exception();
+}
+
+void raise_second_exception()
+{
+  throw second_exception();
+}
+
+template<typename E>
+void capture_exception_of_type(volatile callback_fn_t f)
+{
+  try {
+    f();
+  } catch (E& e) {
+    puts("caught expected exception");
+  } catch (...) {
+    puts("ERROR: caught unexpected exception");
+    throw;
+  }
+}
+
+int main()
+{
+  capture_exception_of_type<first_exception>(raise_first_exception);
+  capture_exception_of_type<second_exception>(raise_second_exception);
+  return 0;
+}
diff --git a/gold/testsuite/icf_test_pr21066.sh b/gold/testsuite/icf_test_pr21066.sh
new file mode 100755
index 0000000..2f3e85d
--- /dev/null
+++ b/gold/testsuite/icf_test_pr21066.sh
@@ -0,0 +1,48 @@
+#!/bin/sh
+
+# icf_test_pr21066.sh -- regression test for ICF tracking exception handling
+# metadata differences
+
+# Copyright (C) 2009-2018 Free Software Foundation, Inc.
+# Written by Joshua Oreman <oremanj@hudson-trading.com>, based on icf_test.sh
+
+# This file is part of gold.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+# MA 02110-1301, USA.
+
+set -e
+
+check()
+{
+    awk "
+BEGIN { discard = 0; }
+/^Discarded input/ { discard = 1; }
+/^Memory map/ { discard = 0; }
+/.*\\.text\\..*capture_exception_of_type.*($2|$3).*/ {
+      act[discard] = act[discard] \" \" \$0;
+}
+END {
+      # printf \"kept\" act[0] \"\\nfolded\" act[1] \"\\n\";
+      if (length(act[0]) != 0 && length(act[1]) != 0)
+	{
+	  printf \"Identical Code Folding improperly folded functions\\n\"
+	  printf \"with same code but different .gcc_except_table\\n\"
+	  exit 1;
+	}
+    }" $1
+}
+
+check icf_test_pr21066.map "first_exception" "second_exception"