[PATCH] gold: Support SHF_GNU_RETAIN
H.J. Lu
hjl.tools@gmail.com
Wed Dec 9 16:07:42 GMT 2020
Keep input SHF_GNU_RETAIN sections and strip output SHF_GNU_RETAIN for
GNU/FreBSD ELFOSABIs.
elfcpp/
PR gold/27039
* elfcpp.h (SHF): Add SHF_GNU_RETAIN.
gold/
PR gold/27039
* layout.cc (Layout::layout): Strip SHF_GNU_RETAIN.
* object.cc (Sized_relobj_file::Sized_relobj_file): Initialize
osabi_.
(Sized_relobj_file::do_layout): Keep SHF_GNU_RETAIN sections for
GNU/FreBSD ELFOSABIs.
* object.h (Sized_relobj_file): Add osabi() and osabi_.
* testsuite/Makefile.am (check_SCRIPTS): Add retain.sh.
(check_DATA): Add retain_1.out retain_2.out.
(MOSTLYCLEANFILES): Add retain_1 retain_2.
(retain_1.out): New target.
(retain_1): Likewise.
(retain_1.o): Likewise.
(retain_2.out): Likewise.
(retain_2): Likewise.
(retain_2.o): Likewise.
* testsuite/Makefile.in: Regenerated.
* testsuite/retain.sh: New file.
* testsuite/retain_1.s: Likewise.
* testsuite/retain_2.s: Likewise.
---
elfcpp/elfcpp.h | 1 +
gold/layout.cc | 20 +++++--
gold/object.cc | 7 ++-
gold/object.h | 7 +++
gold/testsuite/Makefile.am | 16 ++++++
gold/testsuite/Makefile.in | 26 ++++++++--
gold/testsuite/retain.sh | 60 +++++++++++++++++++++
gold/testsuite/retain_1.s | 104 +++++++++++++++++++++++++++++++++++++
gold/testsuite/retain_2.s | 22 ++++++++
9 files changed, 254 insertions(+), 9 deletions(-)
create mode 100755 gold/testsuite/retain.sh
create mode 100644 gold/testsuite/retain_1.s
create mode 100644 gold/testsuite/retain_2.s
diff --git a/elfcpp/elfcpp.h b/elfcpp/elfcpp.h
index 4b6ff94a65..2d333e992f 100644
--- a/elfcpp/elfcpp.h
+++ b/elfcpp/elfcpp.h
@@ -438,6 +438,7 @@ enum SHF
SHF_TLS = 0x400,
SHF_COMPRESSED = 0x800,
SHF_MASKOS = 0x0ff00000,
+ SHF_GNU_RETAIN = 0x200000,
SHF_MASKPROC = 0xf0000000,
// Indicates this section requires ordering in relation to
diff --git a/gold/layout.cc b/gold/layout.cc
index 8563f11099..9c245a8e76 100644
--- a/gold/layout.cc
+++ b/gold/layout.cc
@@ -1186,10 +1186,18 @@ Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
= (parameters->options().text_unlikely_segment()
&& is_prefix_of(".text.unlikely",
object->section_name(shndx).c_str()));
+ elfcpp::Elf_Xword ignored_flags;
+ elfcpp::ELFOSABI osabi = object->osabi();
+ if (osabi == elfcpp::ELFOSABI_GNU
+ || osabi == elfcpp::ELFOSABI_FREEBSD)
+ ignored_flags = elfcpp::SHF_GNU_RETAIN;
+ else
+ ignored_flags = 0;
if (text_unlikely_segment)
{
elfcpp::Elf_Xword flags
- = this->get_output_section_flags(shdr.get_sh_flags());
+ = this->get_output_section_flags(shdr.get_sh_flags()
+ & ~ignored_flags);
Stringpool::Key name_key;
const char* os_name = this->namepool_.add(".text.unlikely", true,
@@ -1212,16 +1220,18 @@ Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
if (it == this->section_segment_map_.end())
{
os = this->choose_output_section(object, name, sh_type,
- shdr.get_sh_flags(), true,
- ORDER_INVALID, false, false,
- true);
+ (shdr.get_sh_flags()
+ & ~ignored_flags),
+ true, ORDER_INVALID,
+ false, false, true);
}
else
{
// We know the name of the output section, directly call
// get_output_section here by-passing choose_output_section.
elfcpp::Elf_Xword flags
- = this->get_output_section_flags(shdr.get_sh_flags());
+ = this->get_output_section_flags(shdr.get_sh_flags()
+ & ~ignored_flags);
const char* os_name = it->second->name;
Stringpool::Key name_key;
diff --git a/gold/object.cc b/gold/object.cc
index 61aed805c2..0e2bcc131a 100644
--- a/gold/object.cc
+++ b/gold/object.cc
@@ -498,6 +498,7 @@ Sized_relobj_file<size, big_endian>::Sized_relobj_file(
deferred_layout_relocs_(),
output_views_(NULL)
{
+ this->osabi_ = static_cast<elfcpp::ELFOSABI>(ehdr.get_e_ident()[elfcpp::EI_OSABI]);
this->e_type_ = ehdr.get_e_type();
}
@@ -1716,10 +1717,14 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
if (is_pass_one && parameters->options().gc_sections())
{
+ elfcpp::ELFOSABI osabi = this->osabi();
if (this->is_section_name_included(name)
|| layout->keep_input_section (this, name)
|| sh_type == elfcpp::SHT_INIT_ARRAY
- || sh_type == elfcpp::SHT_FINI_ARRAY)
+ || sh_type == elfcpp::SHT_FINI_ARRAY
+ || ((osabi == elfcpp::ELFOSABI_GNU
+ || osabi == elfcpp::ELFOSABI_FREEBSD)
+ && shdr.get_sh_flags() & elfcpp::SHF_GNU_RETAIN) != 0)
{
symtab->gc()->worklist().push_back(Section_id(this, i));
}
diff --git a/gold/object.h b/gold/object.h
index 656443f062..e73328663d 100644
--- a/gold/object.h
+++ b/gold/object.h
@@ -2209,6 +2209,11 @@ class Sized_relobj_file : public Sized_relobj<size, big_endian>
e_type() const
{ return this->e_type_; }
+ // Return the EI_OSABI.
+ elfcpp::ELFOSABI
+ osabi() const
+ { return this->osabi_; }
+
// Return the number of symbols. This is only valid after
// Object::add_symbols has been called.
unsigned int
@@ -2849,6 +2854,8 @@ class Sized_relobj_file : public Sized_relobj<size, big_endian>
// General access to the ELF file.
elfcpp::Elf_file<size, big_endian, Object> elf_file_;
+ // The EI_OSABI.
+ elfcpp::ELFOSABI osabi_;
// Type of ELF file (ET_REL or ET_EXEC). ET_EXEC files are allowed
// as input files only for the --just-symbols option.
int e_type_;
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index 739ea98dbe..abaaba6661 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -4466,4 +4466,20 @@ pr26936c.o: pr26936c.s
pr26936d.o: pr26936d.s
$(TEST_AS) --gen-debug -mx86-used-note=yes -o $@ $<
+check_SCRIPTS += retain.sh
+check_DATA += retain_1.out retain_2.out
+MOSTLYCLEANFILES += retain_1 retain_2
+retain_1.out: retain_1
+ $(TEST_NM) $< >$@
+retain_1: retain_1.o ../ld-new
+ ../ld-new -e _start --gc-sections -o $@ retain_1.o
+retain_1.o: retain_1.s
+ $(TEST_AS) -o $@ $<
+retain_2.out: retain_2
+ $(TEST_READELF) -d $< >$@
+retain_2: retain_2.o ../ld-new
+ ../ld-new -pie -e _start --gc-sections -o $@ retain_2.o
+retain_2.o: retain_2.s
+ $(TEST_AS) -o $@ $<
+
endif DEFAULT_TARGET_X86_64
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index 2c03a992cf..79aed4a763 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -1143,12 +1143,13 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \
@DEFAULT_TARGET_S390_TRUE@@NATIVE_OR_CROSS_LINKER_TRUE@ split_s390x_z4_ns split_s390x_n1_ns split_s390x_n2_ns split_s390x_r
@DEFAULT_TARGET_X86_64_TRUE@am__append_116 = *.dwo *.dwp pr26936a \
-@DEFAULT_TARGET_X86_64_TRUE@ pr26936b
+@DEFAULT_TARGET_X86_64_TRUE@ pr26936b retain_1 retain_2
@DEFAULT_TARGET_X86_64_TRUE@am__append_117 = dwp_test_1.sh \
-@DEFAULT_TARGET_X86_64_TRUE@ dwp_test_2.sh pr26936.sh
+@DEFAULT_TARGET_X86_64_TRUE@ dwp_test_2.sh pr26936.sh retain.sh
@DEFAULT_TARGET_X86_64_TRUE@am__append_118 = dwp_test_1.stdout \
@DEFAULT_TARGET_X86_64_TRUE@ dwp_test_2.stdout pr26936a.stdout \
-@DEFAULT_TARGET_X86_64_TRUE@ pr26936b.stdout
+@DEFAULT_TARGET_X86_64_TRUE@ pr26936b.stdout retain_1.out \
+@DEFAULT_TARGET_X86_64_TRUE@ retain_2.out
subdir = testsuite
ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
am__aclocal_m4_deps = $(top_srcdir)/../config/ax_pthread.m4 \
@@ -6492,6 +6493,13 @@ pr26936.sh.log: pr26936.sh
--log-file $$b.log --trs-file $$b.trs \
$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
"$$tst" $(AM_TESTS_FD_REDIRECT)
+retain.sh.log: retain.sh
+ @p='retain.sh'; \
+ b='retain.sh'; \
+ $(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+ --log-file $$b.log --trs-file $$b.trs \
+ $(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+ "$$tst" $(AM_TESTS_FD_REDIRECT)
object_unittest.log: object_unittest$(EXEEXT)
@p='object_unittest$(EXEEXT)'; \
b='object_unittest'; \
@@ -10463,6 +10471,18 @@ uninstall-am:
@DEFAULT_TARGET_X86_64_TRUE@ $(TEST_AS) --gen-debug -mx86-used-note=yes -o $@ $<
@DEFAULT_TARGET_X86_64_TRUE@pr26936d.o: pr26936d.s
@DEFAULT_TARGET_X86_64_TRUE@ $(TEST_AS) --gen-debug -mx86-used-note=yes -o $@ $<
+@DEFAULT_TARGET_X86_64_TRUE@retain_1.out: retain_1
+@DEFAULT_TARGET_X86_64_TRUE@ $(TEST_NM) $< >$@
+@DEFAULT_TARGET_X86_64_TRUE@retain_1: retain_1.o ../ld-new
+@DEFAULT_TARGET_X86_64_TRUE@ ../ld-new -e _start --gc-sections -o $@ retain_1.o
+@DEFAULT_TARGET_X86_64_TRUE@retain_1.o: retain_1.s
+@DEFAULT_TARGET_X86_64_TRUE@ $(TEST_AS) -o $@ $<
+@DEFAULT_TARGET_X86_64_TRUE@retain_2.out: retain_2
+@DEFAULT_TARGET_X86_64_TRUE@ $(TEST_READELF) -d $< >$@
+@DEFAULT_TARGET_X86_64_TRUE@retain_2: retain_2.o ../ld-new
+@DEFAULT_TARGET_X86_64_TRUE@ ../ld-new -pie -e _start --gc-sections -o $@ retain_2.o
+@DEFAULT_TARGET_X86_64_TRUE@retain_2.o: retain_2.s
+@DEFAULT_TARGET_X86_64_TRUE@ $(TEST_AS) -o $@ $<
# Tell versions [3.59,3.63) of GNU make to not export all variables.
# Otherwise a system limit (for SysV at least) may be exceeded.
diff --git a/gold/testsuite/retain.sh b/gold/testsuite/retain.sh
new file mode 100755
index 0000000000..0f5c6951c5
--- /dev/null
+++ b/gold/testsuite/retain.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+
+# retain.sh -- Tests for SHF_GNU_RETAIN.
+
+# Copyright (C) 2020 Free Software Foundation, Inc.
+
+# 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()
+{
+ number_of_occurrence=`egrep "$2" ./$1 -o | wc -l`
+ if [ $number_of_occurrence != $3 ]
+ then
+ echo "$1: \"$2\" $3: Failed"
+ status=1
+ fi
+}
+
+status=0
+check retain_1.out " T fnretain1" 1
+check retain_1.out " b lsretain0.2" 1
+check retain_1.out " b lsretain1.1" 1
+check retain_1.out " d lsretain2.0" 1
+check retain_1.out " B retain0" 1
+check retain_1.out " B retain1" 1
+check retain_1.out " D retain2" 1
+check retain_1.out " b sretain0" 1
+check retain_1.out " b sretain1" 1
+check retain_1.out " d sretain2" 1
+if grep discard retain_1.out
+then
+ echo "retain_1.out: Garbage collection failed"
+ status=1
+fi
+
+check retain_2.out " \(PREINIT_ARRAY\)" 1
+check retain_2.out " \(PREINIT_ARRAYSZ\)" 1
+check retain_2.out " \(INIT_ARRAY\)" 1
+check retain_2.out " \(INIT_ARRAYSZ\)" 1
+check retain_2.out " \(FINI_ARRAY\)" 1
+check retain_2.out " \(FINI_ARRAYSZ\)" 1
+
+exit $status
diff --git a/gold/testsuite/retain_1.s b/gold/testsuite/retain_1.s
new file mode 100644
index 0000000000..f7716faabe
--- /dev/null
+++ b/gold/testsuite/retain_1.s
@@ -0,0 +1,104 @@
+ .global discard0
+ .section .bss.discard0,"aw"
+ .type discard0, %object
+discard0:
+ .zero 2
+
+ .global discard1
+ .section .bss.discard1,"aw"
+ .type discard1, %object
+discard1:
+ .zero 2
+
+ .global discard2
+ .section .data.discard2,"aw"
+ .type discard2, %object
+discard2:
+ .word 1
+
+ .section .bss.sdiscard0,"aw"
+ .type sdiscard0, %object
+sdiscard0:
+ .zero 2
+
+ .section .bss.sdiscard1,"aw"
+ .type sdiscard1, %object
+sdiscard1:
+ .zero 2
+
+ .section .data.sdiscard2,"aw"
+ .type sdiscard2, %object
+sdiscard2:
+ .word 1
+
+ .section .text.fndiscard0,"ax"
+ .global fndiscard0
+ .type fndiscard0, %function
+fndiscard0:
+ .word 0
+
+ .global retain0
+ .section .bss.retain0,"awR"
+ .type retain0, %object
+retain0:
+ .zero 2
+
+ .global retain1
+ .section .bss.retain1,"awR"
+ .type retain1, %object
+retain1:
+ .zero 2
+
+ .global retain2
+ .section .data.retain2,"awR"
+ .type retain2, %object
+retain2:
+ .word 1
+
+ .section .bss.sretain0,"awR"
+ .type sretain0, %object
+sretain0:
+ .zero 2
+
+ .section .bss.sretain1,"awR"
+ .type sretain1, %object
+sretain1:
+ .zero 2
+
+ .section .data.sretain2,"aRw"
+ .type sretain2, %object
+sretain2:
+ .word 1
+
+ .section .text.fnretain1,"Rax"
+ .global fnretain1
+ .type fnretain1, %function
+fnretain1:
+ .word 0
+
+ .section .text.fndiscard2,"ax"
+ .global fndiscard2
+ .type fndiscard2, %function
+fndiscard2:
+ .word 0
+
+ .section .bss.lsretain0,"awR"
+ .type lsretain0.2, %object
+lsretain0.2:
+ .zero 2
+
+ .section .bss.lsretain1,"aRw"
+ .type lsretain1.1, %object
+lsretain1.1:
+ .zero 2
+
+ .section .data.lsretain2,"aRw"
+ .type lsretain2.0, %object
+lsretain2.0:
+ .word 1
+
+ .section .text._start,"ax"
+ .global _start
+ .type _start, %function
+_start:
+ .word 0
diff --git a/gold/testsuite/retain_2.s b/gold/testsuite/retain_2.s
new file mode 100644
index 0000000000..67d86d10cb
--- /dev/null
+++ b/gold/testsuite/retain_2.s
@@ -0,0 +1,22 @@
+ .section .preinit_array.01000,"aw",%preinit_array
+ .dc.a 0
+
+ .section .init_array.01000,"aw",%init_array
+ .dc.a 0
+
+ .section .fini_array.01000,"aw",%fini_array
+ .dc.a 0
+
+ .section .preinit_array.01000,"awR",%preinit_array
+ .dc.a 0
+
+ .section .init_array.01000,"awR",%init_array
+ .dc.a 0
+
+ .section .fini_array.01000,"awR",%fini_array
+ .dc.a 0
+
+ .text
+ .globl _start
+_start:
+ .dc.a 0
--
2.29.2
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