Convert indirect calls to direct when possible.
Please see patch discussion:
https://www.sourceware.org/ml/binutils/2016-05/msg00322.html
2016-06-28 Sriraman Tallam <tmsriram@google.com>
* x86_64.cc (Lazy_view): New class.
(can_convert_mov_to_lea): Templatize function. Make the function
check for appropriate relocation types and use the view parameter
to get section contents.
(can_convert_callq_to_direct): New function.
(Target_x86_64<size>::Scan::global): Refactor.
(Target_x86_64<size>::Relocate::relocate): Refactor. Change any indirect
call via GOT that can be converted.
* testsuite/Makefile.am (x86_64_indirect_call_to_direct.sh): New test.
* testsuite/Makefile.in: Regenerate.
* testsuite/x86_64_indirect_call_to_direct1.s: New file.
* testsuite/x86_64_indirect_jump_to_direct1.s: New file.
diff --git a/gold/ChangeLog b/gold/ChangeLog
index d6bae2b..8b293cd 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,18 @@
+2016-06-28 Sriraman Tallam <tmsriram@google.com>
+
+ * x86_64.cc (Lazy_view): New class.
+ (can_convert_mov_to_lea): Templatize function. Make the function
+ check for appropriate relocation types and use the view parameter
+ to get section contents.
+ (can_convert_callq_to_direct): New function.
+ (Target_x86_64<size>::Scan::global): Refactor.
+ (Target_x86_64<size>::Relocate::relocate): Refactor. Change any indirect
+ call via GOT that can be converted.
+ * testsuite/Makefile.am (x86_64_indirect_call_to_direct.sh): New test.
+ * testsuite/Makefile.in: Regenerate.
+ * testsuite/x86_64_indirect_call_to_direct1.s: New file.
+ * testsuite/x86_64_indirect_jump_to_direct1.s: New file.
+
2016-06-28 Igor Kudrin <ikudrin@accesssoftek.com>
* aarch64.cc (Target_aarch64::Scan::local): Move the call to got_section
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index 9e232e9..9d4326b 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -1096,6 +1096,25 @@
x86_64_mov_to_lea14.stdout: x86_64_mov_to_lea14
$(TEST_OBJDUMP) -dw $< > $@
+check_SCRIPTS += x86_64_indirect_call_to_direct.sh
+check_DATA += x86_64_indirect_call_to_direct1.stdout \
+ x86_64_indirect_jump_to_direct1.stdout
+MOSTLYCLEANFILES += x86_64_indirect_call_to_direct1 \
+ x86_64_indirect_jump_to_direct1
+
+x86_64_indirect_call_to_direct1.o: x86_64_indirect_call_to_direct1.s
+ $(TEST_AS) --64 -mrelax-relocations=yes -o $@ $<
+x86_64_indirect_call_to_direct1: x86_64_indirect_call_to_direct1.o gcctestdir/ld
+ gcctestdir/ld -o $@ $<
+x86_64_indirect_call_to_direct1.stdout: x86_64_indirect_call_to_direct1
+ $(TEST_OBJDUMP) -dw $< > $@
+x86_64_indirect_jump_to_direct1.o: x86_64_indirect_jump_to_direct1.s
+ $(TEST_AS) --64 -mrelax-relocations=yes -o $@ $<
+x86_64_indirect_jump_to_direct1: x86_64_indirect_jump_to_direct1.o gcctestdir/ld
+ gcctestdir/ld -o $@ $<
+x86_64_indirect_jump_to_direct1.stdout: x86_64_indirect_jump_to_direct1
+ $(TEST_OBJDUMP) -dw $< > $@
+
check_SCRIPTS += x86_64_overflow_pc32.sh
check_DATA += x86_64_overflow_pc32.err
MOSTLYCLEANFILES += x86_64_overflow_pc32.err
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index 5b66c9c..894e6dd 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -223,6 +223,7 @@
@GCC_TRUE@@HAVE_STATIC_TRUE@@NATIVE_LINKER_TRUE@@STATIC_TLS_TRUE@@TLS_TRUE@ tls_static_pic_test
@FN_PTRS_IN_SO_WITHOUT_PIC_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@am__append_26 = tls_shared_nonpic_test
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_27 = x86_64_mov_to_lea.sh \
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_indirect_call_to_direct.sh \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_overflow_pc32.sh \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x32_overflow_pc32.sh
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_28 = x86_64_mov_to_lea1.stdout \
@@ -239,6 +240,8 @@
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_mov_to_lea12.stdout \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_mov_to_lea13.stdout \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_mov_to_lea14.stdout \
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_indirect_call_to_direct1.stdout \
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_indirect_jump_to_direct1.stdout \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_overflow_pc32.err \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x32_overflow_pc32.err
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_29 = x86_64_mov_to_lea1 \
@@ -255,6 +258,8 @@
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_mov_to_lea12 \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_mov_to_lea13 \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_mov_to_lea14 \
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_indirect_call_to_direct1 \
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_indirect_jump_to_direct1 \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x86_64_overflow_pc32.err \
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ x32_overflow_pc32.err
@DEFAULT_TARGET_I386_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_30 = i386_mov_to_lea.sh
@@ -4564,6 +4569,8 @@
@p='tls_pie_test.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
x86_64_mov_to_lea.sh.log: x86_64_mov_to_lea.sh
@p='x86_64_mov_to_lea.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
+x86_64_indirect_call_to_direct.sh.log: x86_64_indirect_call_to_direct.sh
+ @p='x86_64_indirect_call_to_direct.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
x86_64_overflow_pc32.sh.log: x86_64_overflow_pc32.sh
@p='x86_64_overflow_pc32.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
x32_overflow_pc32.sh.log: x32_overflow_pc32.sh
@@ -5641,6 +5648,19 @@
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_OBJDUMP) -dw $< > $@
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_mov_to_lea14.stdout: x86_64_mov_to_lea14
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_OBJDUMP) -dw $< > $@
+
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_indirect_call_to_direct1.o: x86_64_indirect_call_to_direct1.s
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_AS) --64 -mrelax-relocations=yes -o $@ $<
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_indirect_call_to_direct1: x86_64_indirect_call_to_direct1.o gcctestdir/ld
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ gcctestdir/ld -o $@ $<
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_indirect_call_to_direct1.stdout: x86_64_indirect_call_to_direct1
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_OBJDUMP) -dw $< > $@
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_indirect_jump_to_direct1.o: x86_64_indirect_jump_to_direct1.s
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_AS) --64 -mrelax-relocations=yes -o $@ $<
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_indirect_jump_to_direct1: x86_64_indirect_jump_to_direct1.o gcctestdir/ld
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ gcctestdir/ld -o $@ $<
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_indirect_jump_to_direct1.stdout: x86_64_indirect_jump_to_direct1
+@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_OBJDUMP) -dw $< > $@
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_overflow_pc32.o: x86_64_overflow_pc32.s
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_AS) -o $@ $<
@DEFAULT_TARGET_X86_64_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@x86_64_overflow_pc32.err: x86_64_overflow_pc32.o gcctestdir/ld
diff --git a/gold/testsuite/x86_64_indirect_call_to_direct.sh b/gold/testsuite/x86_64_indirect_call_to_direct.sh
new file mode 100755
index 0000000..916e1a3
--- /dev/null
+++ b/gold/testsuite/x86_64_indirect_call_to_direct.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+
+# x86_64_indirect_call_to_direct.sh -- a test for indirect call(jump) to direct
+# conversion.
+
+# Copyright (C) 2016 Free Software Foundation, Inc.
+# Written by Sriraman Tallam <tmsriram@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.
+
+set -e
+
+grep -q "callq[ ]\+[a-f0-9]\+ <foo>" x86_64_indirect_call_to_direct1.stdout
+grep -q "jmpq[ ]\+[a-f0-9]\+ <foo>" x86_64_indirect_jump_to_direct1.stdout
diff --git a/gold/testsuite/x86_64_indirect_call_to_direct1.s b/gold/testsuite/x86_64_indirect_call_to_direct1.s
new file mode 100644
index 0000000..5ca2e38
--- /dev/null
+++ b/gold/testsuite/x86_64_indirect_call_to_direct1.s
@@ -0,0 +1,12 @@
+ .text
+ .globl foo
+ .type foo, @function
+foo:
+ ret
+ .size foo, .-foo
+ .globl main
+ .type main, @function
+main:
+ call *foo@GOTPCREL(%rip)
+ ret
+ .size main, .-main
diff --git a/gold/testsuite/x86_64_indirect_jump_to_direct1.s b/gold/testsuite/x86_64_indirect_jump_to_direct1.s
new file mode 100644
index 0000000..b817e34
--- /dev/null
+++ b/gold/testsuite/x86_64_indirect_jump_to_direct1.s
@@ -0,0 +1,11 @@
+ .text
+ .globl foo
+ .type foo, @function
+foo:
+ ret
+ .size foo, .-foo
+ .globl main
+ .type main, @function
+main:
+ jmp *foo@GOTPCREL(%rip)
+ .size main, .-main
diff --git a/gold/x86_64.cc b/gold/x86_64.cc
index d069957..6c511e2 100644
--- a/gold/x86_64.cc
+++ b/gold/x86_64.cc
@@ -403,6 +403,33 @@
static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
};
+template<int size>
+class Lazy_view
+{
+ public:
+ Lazy_view(Sized_relobj_file<size, false>* object, unsigned int data_shndx)
+ : object_(object), data_shndx_(data_shndx), view_(NULL), view_size_(0)
+ { }
+
+ inline unsigned char
+ operator[](size_t offset)
+ {
+ if (this->view_ == NULL)
+ this->view_ = this->object_->section_contents(this->data_shndx_,
+ &this->view_size_,
+ true);
+ if (offset >= this->view_size_)
+ return 0;
+ return this->view_[offset];
+ }
+
+ private:
+ Sized_relobj_file<size, false>* object_;
+ unsigned int data_shndx_;
+ const unsigned char* view_;
+ section_size_type view_size_;
+};
+
// The x86_64 target class.
// See the ABI at
// http://www.x86-64.org/documentation/abi.pdf
@@ -876,19 +903,62 @@
// conversion from
// mov foo@GOTPCREL(%rip), %reg
// to lea foo(%rip), %reg.
- static bool
- can_convert_mov_to_lea(const Symbol* gsym)
+ template<class View_type>
+ static inline bool
+ can_convert_mov_to_lea(const Symbol* gsym, unsigned int r_type,
+ size_t r_offset, View_type* view)
{
gold_assert(gsym != NULL);
- return (gsym->type() != elfcpp::STT_GNU_IFUNC
- && !gsym->is_undefined ()
- && !gsym->is_from_dynobj()
- && !gsym->is_preemptible()
- && (!parameters->options().shared()
- || (gsym->visibility() != elfcpp::STV_DEFAULT
- && gsym->visibility() != elfcpp::STV_PROTECTED)
- || parameters->options().Bsymbolic())
- && strcmp(gsym->name(), "_DYNAMIC") != 0);
+ // We cannot do the conversion unless it's one of these relocations.
+ if (r_type != elfcpp::R_X86_64_GOTPCREL
+ && r_type != elfcpp::R_X86_64_GOTPCRELX
+ && r_type != elfcpp::R_X86_64_REX_GOTPCRELX)
+ return false;
+ // We cannot convert references to IFUNC symbols, or to symbols that
+ // are not local to the current module.
+ if (gsym->type() == elfcpp::STT_GNU_IFUNC
+ || gsym->is_undefined ()
+ || gsym->is_from_dynobj()
+ || gsym->is_preemptible())
+ return false;
+ // If we are building a shared object and the symbol is protected, we may
+ // need to go through the GOT.
+ if (parameters->options().shared()
+ && gsym->visibility() == elfcpp::STV_PROTECTED)
+ return false;
+ // We cannot convert references to the _DYNAMIC symbol.
+ if (strcmp(gsym->name(), "_DYNAMIC") == 0)
+ return false;
+ // Check for a MOV opcode.
+ return (*view)[r_offset - 2] == 0x8b;
+ }
+
+ // Convert
+ // callq *foo@GOTPCRELX(%rip) to
+ // addr32 callq foo
+ // and jmpq *foo@GOTPCRELX(%rip) to
+ // jmpq foo
+ // nop
+ template<class View_type>
+ static inline bool
+ can_convert_callq_to_direct(const Symbol* gsym, unsigned int r_type,
+ size_t r_offset, View_type* view)
+ {
+ gold_assert(gsym != NULL);
+ // We cannot do the conversion unless it's a GOTPCRELX relocation.
+ if (r_type != elfcpp::R_X86_64_GOTPCRELX)
+ return false;
+ // We cannot convert references to IFUNC symbols, or to symbols that
+ // are not local to the current module.
+ if (gsym->type() == elfcpp::STT_GNU_IFUNC
+ || gsym->is_undefined ()
+ || gsym->is_from_dynobj()
+ || gsym->is_preemptible())
+ return false;
+ // Check for a CALLQ or JMPQ opcode.
+ return ((*view)[r_offset - 2] == 0xff
+ && ((*view)[r_offset - 1] == 0x15
+ || (*view)[r_offset - 1] == 0x25));
}
// Adjust TLS relocation type based on the options and whether this
@@ -2935,19 +3005,24 @@
// If we convert this from
// mov foo@GOTPCREL(%rip), %reg
// to lea foo(%rip), %reg.
+ // OR
+ // if we convert
+ // (callq|jmpq) *foo@GOTPCRELX(%rip) to
+ // (callq|jmpq) foo
// in Relocate::relocate, then there is nothing to do here.
- if ((r_type == elfcpp::R_X86_64_GOTPCREL
- || r_type == elfcpp::R_X86_64_GOTPCRELX
- || r_type == elfcpp::R_X86_64_REX_GOTPCRELX)
- && reloc.get_r_offset() >= 2
- && Target_x86_64<size>::can_convert_mov_to_lea(gsym))
- {
- section_size_type stype;
- const unsigned char* view = object->section_contents(data_shndx,
- &stype, true);
- if (view[reloc.get_r_offset() - 2] == 0x8b)
- break;
- }
+
+ Lazy_view<size> view(object, data_shndx);
+ size_t r_offset = reloc.get_r_offset();
+ if (r_offset >= 2
+ && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type,
+ r_offset, &view))
+ break;
+
+ if (r_offset >= 2
+ && Target_x86_64<size>::can_convert_callq_to_direct(gsym, r_type,
+ r_offset,
+ &view))
+ break;
if (gsym->final_value_is_known())
{
@@ -3629,15 +3704,56 @@
// mov foo@GOTPCREL(%rip), %reg
// to lea foo(%rip), %reg.
// if possible.
- if (rela.get_r_offset() >= 2
- && view[-2] == 0x8b
- && ((gsym == NULL && !psymval->is_ifunc_symbol())
- || (gsym != NULL
- && Target_x86_64<size>::can_convert_mov_to_lea(gsym))))
+ if ((gsym == NULL
+ && rela.get_r_offset() >= 2
+ && view[-2] == 0x8b
+ && !psymval->is_ifunc_symbol())
+ || (gsym != NULL
+ && rela.get_r_offset() >= 2
+ && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type,
+ 0, &view)))
{
view[-2] = 0x8d;
Reloc_funcs::pcrela32(view, object, psymval, addend, address);
}
+ // Convert
+ // callq *foo@GOTPCRELX(%rip) to
+ // addr32 callq foo
+ // and jmpq *foo@GOTPCRELX(%rip) to
+ // jmpq foo
+ // nop
+ else if (gsym != NULL
+ && rela.get_r_offset() >= 2
+ && Target_x86_64<size>::can_convert_callq_to_direct(gsym,
+ r_type,
+ 0, &view))
+ {
+ if (view[-1] == 0x15)
+ {
+ // Convert callq *foo@GOTPCRELX(%rip) to addr32 callq.
+ // Opcode of addr32 is 0x67 and opcode of direct callq is 0xe8.
+ view[-2] = 0x67;
+ view[-1] = 0xe8;
+ // Convert GOTPCRELX to 32-bit pc relative reloc.
+ Reloc_funcs::pcrela32(view, object, psymval, addend, address);
+ }
+ else
+ {
+ // Convert jmpq *foo@GOTPCRELX(%rip) to
+ // jmpq foo
+ // nop
+ // The opcode of direct jmpq is 0xe9.
+ view[-2] = 0xe9;
+ // The opcode of nop is 0x90.
+ view[3] = 0x90;
+ // Convert GOTPCRELX to 32-bit pc relative reloc. jmpq is rip
+ // relative and since the instruction following the jmpq is now
+ // the nop, offset the address by 1 byte. The start of the
+ // relocation also moves ahead by 1 byte.
+ Reloc_funcs::pcrela32(&view[-1], object, psymval, addend,
+ address - 1);
+ }
+ }
else
{
if (gsym != NULL)
