+2017-02-03 Rahul Chaudhry <rahulchaudhry@google.com>
+
+ * x86_64.cc (Target_x86_64::do_can_check_for_function_pointers):
+ Return true even when building pie binaries.
+ (Target_x86_64::possible_function_pointer_reloc): Check opcode
+ for R_X86_64_PC32 relocations.
+ (Target_x86_64::local_reloc_may_be_function_pointer): Pass
+ extra arguments to local_reloc_may_be_function_pointer.
+ (Target_x86_64::global_reloc_may_be_function_pointer): Likewise.
+ * gc.h (gc_process_relocs): Add check for STT_FUNC.
+ * testsuite/Makefile.am (icf_safe_pie_test): New test case.
+ * testsuite/Makefile.in: Regenerate.
+ * testsuite/icf_safe_pie_test.sh: New shell script.
+
2017-02-03 Alan Modra <amodra@gmail.com>
* powerpc.cc (Powerpc_relobj::make_toc_relative): Don't crash
// When doing safe folding, check to see if this relocation is that
// of a function pointer being taken.
if (gsym->source() == Symbol::FROM_OBJECT
+ && gsym->type() == elfcpp::STT_FUNC
&& check_section_for_function_pointers
&& dst_obj != NULL
&& (!is_ordinary
icf_safe_test_2.stdout: icf_safe_test
$(TEST_READELF) -h $< > $@
+check_SCRIPTS += icf_safe_pie_test.sh
+check_DATA += icf_safe_pie_test_1.stdout icf_safe_pie_test_2.stdout icf_safe_pie_test.map
+MOSTLYCLEANFILES += icf_safe_pie_test icf_safe_pie_test.map
+icf_safe_pie_test.o: icf_safe_test.cc
+ $(CXXCOMPILE) -O0 -c -ffunction-sections -fPIE -g -o $@ $<
+icf_safe_pie_test: icf_safe_pie_test.o gcctestdir/ld
+ $(CXXLINK) -o icf_safe_pie_test -Bgcctestdir/ -Wl,--icf=safe,-Map,icf_safe_pie_test.map icf_safe_pie_test.o -pie
+icf_safe_pie_test.map: icf_safe_pie_test
+ @touch icf_safe_pie_test.map
+icf_safe_pie_test_1.stdout: icf_safe_pie_test
+ $(TEST_NM) $< > $@
+icf_safe_pie_test_2.stdout: icf_safe_pie_test
+ $(TEST_READELF) -h $< > $@
+
check_SCRIPTS += icf_safe_so_test.sh
check_DATA += icf_safe_so_test_1.stdout icf_safe_so_test_2.stdout icf_safe_so_test.map
MOSTLYCLEANFILES += icf_safe_so_test icf_safe_so_test.map
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_test.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 \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_so_test.sh \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ final_layout.sh \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ text_section_grouping.sh \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_test_1.stdout \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_test_2.stdout \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_test.map \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_pie_test_1.stdout \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_pie_test_2.stdout \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_pie_test.map \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_so_test_1.stdout \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_so_test_2.stdout \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_so_test.map \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_test icf_test.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 \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_pie_test.map \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_so_test \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ icf_safe_so_test.map \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ final_layout \
@p='icf_keep_unique_test.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
icf_safe_test.sh.log: icf_safe_test.sh
@p='icf_safe_test.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
+icf_safe_pie_test.sh.log: icf_safe_pie_test.sh
+ @p='icf_safe_pie_test.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
icf_safe_so_test.sh.log: icf_safe_so_test.sh
@p='icf_safe_so_test.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
final_layout.sh.log: final_layout.sh
@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_NM) $< > $@
@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_safe_test_2.stdout: icf_safe_test
@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_READELF) -h $< > $@
+@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_safe_pie_test.o: icf_safe_test.cc
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXCOMPILE) -O0 -c -ffunction-sections -fPIE -g -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_safe_pie_test: icf_safe_pie_test.o gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXLINK) -o icf_safe_pie_test -Bgcctestdir/ -Wl,--icf=safe,-Map,icf_safe_pie_test.map icf_safe_pie_test.o -pie
+@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_safe_pie_test.map: icf_safe_pie_test
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ @touch icf_safe_pie_test.map
+@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_safe_pie_test_1.stdout: icf_safe_pie_test
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_NM) $< > $@
+@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_safe_pie_test_2.stdout: icf_safe_pie_test
+@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_READELF) -h $< > $@
@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_safe_so_test.o: icf_safe_so_test.cc
@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXCOMPILE) -O0 -c -ffunction-sections -fPIC -g -o $@ $<
@GCC_TRUE@@NATIVE_LINKER_TRUE@icf_safe_so_test: icf_safe_so_test.o gcctestdir/ld
--- /dev/null
+#!/bin/sh
+
+# icf_safe_pie_test.sh -- test --icf=safe -pie
+
+# Copyright (C) 2009-2017 Free Software Foundation, Inc.
+# Written by Sriraman Tallam <tmsriram@google.com>.
+# Modified by Rahul Chaudhry <rahulchaudhry@google.com>.
+
+# 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 --icf=safe works with
+# -pie as expected. File icf_safe_test.cc is in this test. This
+# program checks if only ctors and dtors are folded, except for
+# the architectures which use relocation types and instruction
+# opcodes to detect if function pointers are taken.
+
+set -e
+
+check_nofold()
+{
+ func_addr_1=`grep $2 $1 | awk '{print $1}'`
+ func_addr_2=`grep $3 $1 | awk '{print $1}'`
+ if [ $func_addr_1 = $func_addr_2 ]
+ then
+ echo "Safe Identical Code Folding folded" $2 "and" $3
+ exit 1
+ fi
+}
+
+check_fold()
+{
+ awk "
+BEGIN { discard = 0; }
+/^Discarded input/ { discard = 1; }
+/^Memory map/ { discard = 0; }
+/.*\\.text\\..*($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 \"Safe Identical Code Folding did not fold $2 and $3\\n\"
+ exit 1;
+ }
+ }" $1
+}
+
+arch_specific_safe_fold()
+{
+ if grep -q -e "Advanced Micro Devices X86-64" -e "Intel 80386" -e "ARM" -e "TILE" -e "PowerPC" -e "AArch64" -e "IBM S/390" $2;
+ then
+ check_fold $3 $4 $5
+ else
+ check_nofold $1 $4 $5
+ fi
+}
+
+arch_specific_safe_fold icf_safe_pie_test_1.stdout icf_safe_pie_test_2.stdout \
+ icf_safe_pie_test.map "kept_func_1" "kept_func_2"
+check_fold icf_safe_pie_test.map "_ZN1AD2Ev" "_ZN1AC2Ev"
+check_nofold icf_safe_pie_test_1.stdout "kept_func_3" "kept_func_1"
+check_nofold icf_safe_pie_test_1.stdout "kept_func_3" "kept_func_2"
// and global_reloc_may_be_function_pointer)
// if a function's pointer is taken. ICF uses this in safe mode to only
// fold those functions whose pointer is defintely not taken. For x86_64
- // pie binaries, safe ICF cannot be done by looking at relocation types.
+ // pie binaries, safe ICF cannot be done by looking at only relocation
+ // types, and for certain cases (e.g. R_X86_64_PC32), the instruction
+ // opcode is checked as well to distinguish a function call from taking
+ // a function's pointer.
bool
do_can_check_for_function_pointers() const
- { return !parameters->options().pie(); }
+ { return true; }
// Return the base for a DW_EH_PE_datarel encoding.
uint64_t
check_non_pic(Relobj*, unsigned int r_type, Symbol*);
inline bool
- possible_function_pointer_reloc(unsigned int r_type);
+ possible_function_pointer_reloc(Sized_relobj_file<size, false>* src_obj,
+ unsigned int src_indx,
+ unsigned int r_offset,
+ unsigned int r_type);
bool
reloc_needs_plt_for_ifunc(Sized_relobj_file<size, false>*,
// Returns true if this relocation type could be that of a function pointer.
template<int size>
inline bool
-Target_x86_64<size>::Scan::possible_function_pointer_reloc(unsigned int r_type)
+Target_x86_64<size>::Scan::possible_function_pointer_reloc(
+ Sized_relobj_file<size, false>* src_obj,
+ unsigned int src_indx,
+ unsigned int r_offset,
+ unsigned int r_type)
{
switch (r_type)
{
{
return true;
}
+ case elfcpp::R_X86_64_PC32:
+ {
+ // This relocation may be used both for function calls and
+ // for taking address of a function. We distinguish between
+ // them by checking the opcodes.
+ uint64_t sh_flags = src_obj->section_flags(src_indx);
+ bool is_executable = (sh_flags & elfcpp::SHF_EXECINSTR) != 0;
+ if (is_executable)
+ {
+ section_size_type stype;
+ const unsigned char* view = src_obj->section_contents(src_indx,
+ &stype,
+ true);
+
+ // call
+ if (r_offset >= 1
+ && view[r_offset - 1] == 0xe8)
+ return false;
+
+ // jmp
+ if (r_offset >= 1
+ && view[r_offset - 1] == 0xe9)
+ return false;
+
+ // jo/jno/jb/jnb/je/jne/jna/ja/js/jns/jp/jnp/jl/jge/jle/jg
+ if (r_offset >= 2
+ && view[r_offset - 2] == 0x0f
+ && view[r_offset - 1] >= 0x80
+ && view[r_offset - 1] <= 0x8f)
+ return false;
+ }
+
+ // Be conservative and treat all others as function pointers.
+ return true;
+ }
}
return false;
}
Symbol_table* ,
Layout* ,
Target_x86_64<size>* ,
- Sized_relobj_file<size, false>* ,
- unsigned int ,
+ Sized_relobj_file<size, false>* src_obj,
+ unsigned int src_indx,
Output_section* ,
- const elfcpp::Rela<size, false>& ,
+ const elfcpp::Rela<size, false>& reloc,
unsigned int r_type,
const elfcpp::Sym<size, false>&)
{
// When building a shared library, do not fold any local symbols as it is
// not possible to distinguish pointer taken versus a call by looking at
// the relocation types.
- return (parameters->options().shared()
- || possible_function_pointer_reloc(r_type));
+ if (parameters->options().shared())
+ return true;
+
+ return possible_function_pointer_reloc(src_obj, src_indx,
+ reloc.get_r_offset(), r_type);
}
// For safe ICF, scan a relocation for a global symbol to check if it
Symbol_table*,
Layout* ,
Target_x86_64<size>* ,
- Sized_relobj_file<size, false>* ,
- unsigned int ,
+ Sized_relobj_file<size, false>* src_obj,
+ unsigned int src_indx,
Output_section* ,
- const elfcpp::Rela<size, false>& ,
+ const elfcpp::Rela<size, false>& reloc,
unsigned int r_type,
Symbol* gsym)
{
// When building a shared library, do not fold symbols whose visibility
// is hidden, internal or protected.
- return ((parameters->options().shared()
- && (gsym->visibility() == elfcpp::STV_INTERNAL
- || gsym->visibility() == elfcpp::STV_PROTECTED
- || gsym->visibility() == elfcpp::STV_HIDDEN))
- || possible_function_pointer_reloc(r_type));
+ if (parameters->options().shared()
+ && (gsym->visibility() == elfcpp::STV_INTERNAL
+ || gsym->visibility() == elfcpp::STV_PROTECTED
+ || gsym->visibility() == elfcpp::STV_HIDDEN))
+ return true;
+
+ return possible_function_pointer_reloc(src_obj, src_indx,
+ reloc.get_r_offset(), r_type);
}
// Scan a relocation for a global symbol.
projects / binutils-gdb.git / commitdiff