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Re: [PATCH 2/2] [GOLD] Add plugin API for processing plugin-added input files
- From: Stephen Crane <sjc at immunant dot com>
- To: Cary Coutant <ccoutant at gmail dot com>
- Cc: Binutils <binutils at sourceware dot org>, Sriraman Tallam <tmsriram at google dot com>
- Date: Mon, 25 Sep 2017 18:46:39 -0700
- Subject: Re: [PATCH 2/2] [GOLD] Add plugin API for processing plugin-added input files
- Authentication-results: sourceware.org; auth=none
Here is a gold test for the new API. I've included just the test in
this patch, hopefully that's ok. I wasn't sure if it was better to
have a separate shell script for the new test or combine it with
plugin_final_layout.sh since they are testing for the same result. If
you have any opinions on that, I'm happy to change it.
New test exercises the new input hook by generating a new file using the basic
test plugin and then reordering its sections and assigning sections to unique
segments in a second plugin.
gold/ChangeLog:
2017-09-25 Stephen Crane <sjc@immunant.com.com>
* testsuite/plugin_new_section_layout.c: New plugin to test
new_input plugin API.
* testsuite/plugin_layout_new_file.sh: New test shell script based
on plugin_final_layout.sh.
* testsuite/Makefile.am (plugin_layout_new_file): New test case.
* testsuite/Makefile.in: Regenerate.
---
gold/testsuite/Makefile.am | 19 +++
gold/testsuite/Makefile.in | 27 ++++-
gold/testsuite/plugin_layout_new_file.sh | 91 +++++++++++++++
gold/testsuite/plugin_new_section_layout.c | 181 +++++++++++++++++++++++++++++
5 files changed, 324 insertions(+), 3 deletions(-)
create mode 100755 gold/testsuite/plugin_layout_new_file.sh
create mode 100644 gold/testsuite/plugin_new_section_layout.c
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index 26ee77abcc..e2de96c69b 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -2390,6 +2390,25 @@ plugin_section_alignment.so:
plugin_section_alignment.o gcctestdir/ld
plugin_section_alignment.o: plugin_section_alignment.cc
$(CXXCOMPILE) -O0 -c -fpic -o $@ $<
+check_SCRIPTS += plugin_layout_new_file.sh
+check_DATA += plugin_layout_new_file.stdout
plugin_layout_new_file_readelf.stdout
+MOSTLYCLEANFILES += plugin_layout_new_file
+plugin_layout_new_file.o: plugin_final_layout.cc
+ $(CXXCOMPILE) -O0 -c -ffunction-sections -fdata-sections -g -o $@ $<
+plugin_layout_new_file.o.syms: plugin_layout_new_file.o
+ $(TEST_READELF) -sW $< >$@ 2>/dev/null
+plugin_layout_new_file: plugin_layout_new_file.o.syms plugin_test.so
plugin_new_section_layout.so gcctestdir/ld
+ $(CXXLINK) -Bgcctestdir/ -Wl,--plugin,"./plugin_test.so"
-Wl,--plugin,"./plugin_new_section_layout.so"
plugin_layout_new_file.o.syms
+plugin_layout_new_file.stdout: plugin_layout_new_file
+ $(TEST_NM) -n --synthetic plugin_layout_new_file >
plugin_layout_new_file.stdout
+plugin_layout_new_file_readelf.stdout: plugin_layout_new_file
+ $(TEST_READELF) -Wl plugin_layout_new_file >
plugin_layout_new_file_readelf.stdout
+
+plugin_new_section_layout.so: plugin_new_section_layout.o gcctestdir/ld
+ $(LINK) -Bgcctestdir/ -shared plugin_new_section_layout.o
+plugin_new_section_layout.o: plugin_new_section_layout.c
+ $(COMPILE) -O0 -c -fpic -o $@ $<
+
endif PLUGINS
check_PROGRAMS += exclude_libs_test
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index eae68b56cb..9bab136100 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -570,12 +570,16 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2)
$(am__EXEEXT_3) \
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@@TLS_TRUE@am__append_51 =
plugin_test_tls.err
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@am__append_52 = unused.c \
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_final_layout \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_layout_with_alignment
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_layout_with_alignment \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_layout_new_file
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@am__append_53 =
plugin_final_layout.sh \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_layout_with_alignment.sh
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_layout_with_alignment.sh \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_layout_new_file.sh
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@am__append_54 =
plugin_final_layout.stdout \
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@
plugin_final_layout_readelf.stdout \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@
plugin_layout_with_alignment.stdout
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@
plugin_layout_with_alignment.stdout \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ plugin_layout_new_file.stdout \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@
plugin_layout_new_file_readelf.stdout
@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_55 = exclude_libs_test \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ local_labels_test \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ discard_locals_test
@@ -5220,6 +5224,8 @@ plugin_final_layout.sh.log: plugin_final_layout.sh
@p='plugin_final_layout.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst"
$(am__check_post)
plugin_layout_with_alignment.sh.log: plugin_layout_with_alignment.sh
@p='plugin_layout_with_alignment.sh'; $(am__check_pre)
$(LOG_COMPILE) "$$tst" $(am__check_post)
+plugin_layout_new_file.sh.log: plugin_layout_new_file.sh
+ @p='plugin_layout_new_file.sh'; $(am__check_pre) $(LOG_COMPILE)
"$$tst" $(am__check_post)
exclude_libs_test.sh.log: exclude_libs_test.sh
@p='exclude_libs_test.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst"
$(am__check_post)
discard_locals_test.sh.log: discard_locals_test.sh
@@ -6978,6 +6984,21 @@ uninstall-am:
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(CXXLINK) -Bgcctestdir/
-shared plugin_section_alignment.o
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_section_alignment.o:
plugin_section_alignment.cc
@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(CXXCOMPILE) -O0 -c
-fpic -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_layout_new_file.o:
plugin_final_layout.cc
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(CXXCOMPILE) -O0 -c
-ffunction-sections -fdata-sections -g -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_layout_new_file.o.syms:
plugin_layout_new_file.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(TEST_READELF) -sW $<
>$@ 2>/dev/null
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_layout_new_file:
plugin_layout_new_file.o.syms plugin_test.so
plugin_new_section_layout.so gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(CXXLINK) -Bgcctestdir/
-Wl,--plugin,"./plugin_test.so"
-Wl,--plugin,"./plugin_new_section_layout.so"
plugin_layout_new_file.o.syms
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_layout_new_file.stdout:
plugin_layout_new_file
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(TEST_NM) -n
--synthetic plugin_layout_new_file > plugin_layout_new_file.stdout
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_layout_new_file_readelf.stdout:
plugin_layout_new_file
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(TEST_READELF) -Wl
plugin_layout_new_file > plugin_layout_new_file_readelf.stdout
+
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_new_section_layout.so:
plugin_new_section_layout.o gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(LINK) -Bgcctestdir/
-shared plugin_new_section_layout.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@plugin_new_section_layout.o:
plugin_new_section_layout.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@ $(COMPILE) -O0 -c -fpic -o $@ $<
@GCC_TRUE@@NATIVE_LINKER_TRUE@exclude_libs_test.syms: exclude_libs_test
@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(TEST_READELF) -sW $< >$@ 2>/dev/null
@GCC_TRUE@@NATIVE_LINKER_TRUE@libexclude_libs_test_1.a: exclude_libs_test_1.o
diff --git a/gold/testsuite/plugin_layout_new_file.sh
b/gold/testsuite/plugin_layout_new_file.sh
new file mode 100755
index 0000000000..09885e67f0
--- /dev/null
+++ b/gold/testsuite/plugin_layout_new_file.sh
@@ -0,0 +1,91 @@
+#!/bin/sh
+
+# plugin_new_section_layout.sh -- test
+
+# Copyright (C) 2011-2017 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.
+
+# The goal of this program is to verify if plugin section reordering and
+# assignment works for plugin-created object files. File final_layout.cc is in
+# this test.
+
+
+set -e
+
+check()
+{
+ awk "
+BEGIN { saw1 = 0; saw2 = 0; err = 0; }
+/.*$2\$/ { saw1 = 1; }
+/.*$3\$/ {
+ saw2 = 1;
+ if (!saw1)
+ {
+ printf \"layout of $2 and $3 is not right\\n\";
+ err = 1;
+ exit 1;
+ }
+ }
+END {
+ if (!saw1 && !err)
+ {
+ printf \"did not see $2\\n\";
+ exit 1;
+ }
+ if (!saw2 && !err)
+ {
+ printf \"did not see $3\\n\";
+ exit 1;
+ }
+ }" $1
+}
+
+# With readelf -l, an ELF Section to Segment mapping is printed as :
+##############################################
+# Section to Segment mapping:
+# Segment Sections...
+# ...
+# 0x .text.plugin_created_unique
+# ...
+##############################################
+# Check of .text.plugin_created_unique is the only section in the segment.
+check_unique_segment()
+{
+ awk "
+BEGIN { saw_section = 0; saw_unique = 0; }
+/$2/ { saw_section = 1; }
+/[ ]*0[0-9][ ]*$2[ ]*\$/ { saw_unique = 1; }
+END {
+ if (!saw_section)
+ {
+ printf \"Section $2 not seen in output\\n\";
+ exit 1;
+ }
+ else if (!saw_unique)
+ {
+ printf \"Unique segment not seen for: $2\\n\";
+ exit 1;
+ }
+ }" $1
+}
+
+check plugin_layout_new_file.stdout "_Z3foov" "_Z3barv"
+check plugin_layout_new_file.stdout "_Z3barv" "_Z3bazv"
+check_unique_segment plugin_layout_new_file_readelf.stdout
".text.plugin_created_unique"
diff --git a/gold/testsuite/plugin_new_section_layout.c
b/gold/testsuite/plugin_new_section_layout.c
new file mode 100644
index 0000000000..f27ad4c530
--- /dev/null
+++ b/gold/testsuite/plugin_new_section_layout.c
@@ -0,0 +1,181 @@
+/* plugin_new_section_layout.c -- Simple plugin to reorder function sections in
+ plugin-generated objects
+
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ Written by Stephen Crane <sjc@immunant.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. */
+
+/* This plugin tests the new_input API of the linker plugin interface that
+ * allows plugins to modify section layout and assign sections to segments for
+ * sections in plugin-generated object files. It assumes that another plugin is
+ * also in use which will add new files. In practice a plugin is likely to
+ * generate new input files itself in all_symbols_read and want to
+ * reorder/assign sections for these files in the new_input_hook callback. */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include "plugin-api.h"
+#include "elf/common.h"
+
+static ld_plugin_get_input_section_count get_input_section_count = NULL;
+static ld_plugin_get_input_section_type get_input_section_type = NULL;
+static ld_plugin_get_input_section_name get_input_section_name = NULL;
+static ld_plugin_update_section_order update_section_order = NULL;
+static ld_plugin_allow_section_ordering allow_section_ordering = NULL;
+static ld_plugin_allow_unique_segment_for_sections
+ allow_unique_segment_for_sections = NULL;
+static ld_plugin_unique_segment_for_sections
unique_segment_for_sections = NULL;
+
+enum ld_plugin_status onload(struct ld_plugin_tv *tv);
+enum ld_plugin_status new_input_hook(const struct ld_plugin_input_file *file);
+
+/* Plugin entry point. */
+enum ld_plugin_status
+onload(struct ld_plugin_tv *tv)
+{
+ struct ld_plugin_tv *entry;
+ for (entry = tv; entry->tv_tag != LDPT_NULL; ++entry)
+ {
+ switch (entry->tv_tag)
+ {
+ case LDPT_GET_INPUT_SECTION_COUNT:
+ get_input_section_count = *entry->tv_u.tv_get_input_section_count;
+ break;
+ case LDPT_GET_INPUT_SECTION_TYPE:
+ get_input_section_type = *entry->tv_u.tv_get_input_section_type;
+ break;
+ case LDPT_GET_INPUT_SECTION_NAME:
+ get_input_section_name = *entry->tv_u.tv_get_input_section_name;
+ break;
+ case LDPT_UPDATE_SECTION_ORDER:
+ update_section_order = *entry->tv_u.tv_update_section_order;
+ break;
+ case LDPT_ALLOW_SECTION_ORDERING:
+ allow_section_ordering = *entry->tv_u.tv_allow_section_ordering;
+ break;
+ case LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS:
+ allow_unique_segment_for_sections
+ = *entry->tv_u.tv_allow_unique_segment_for_sections;
+ break;
+ case LDPT_UNIQUE_SEGMENT_FOR_SECTIONS:
+ unique_segment_for_sections
+ = *entry->tv_u.tv_unique_segment_for_sections;
+ break;
+ case LDPT_REGISTER_NEW_INPUT_HOOK:
+ assert((*entry->tv_u.tv_register_new_input) (new_input_hook)
+ == LDPS_OK);
+ break;
+ default:
+ break;
+ }
+ }
+
+ if (get_input_section_count == NULL
+ || get_input_section_type == NULL
+ || get_input_section_name == NULL
+ || update_section_order == NULL
+ || allow_section_ordering == NULL
+ || allow_unique_segment_for_sections == NULL
+ || unique_segment_for_sections == NULL)
+ {
+ fprintf(stderr, "Some interfaces are missing\n");
+ return LDPS_ERR;
+ }
+
+ /* Inform the linker to prepare for section reordering. */
+ (*allow_section_ordering)();
+ /* Inform the linker to prepare to map some sections to unique
+ segments. */
+ (*allow_unique_segment_for_sections)();
+
+ return LDPS_OK;
+}
+
+inline static int is_prefix_of(const char *prefix, const char *str)
+{
+ return strncmp(prefix, str, strlen (prefix)) == 0;
+}
+
+/* This function is called by the linker when new files are added by a plugin.
+ We can now tell the linker the desired function order since we have a file
+ handle for the newly added file. */
+
+enum ld_plugin_status
+new_input_hook(const struct ld_plugin_input_file *file)
+{
+ struct ld_plugin_section section_list[3];
+ int num_entries = 0;
+ unsigned int count;
+
+ if (get_input_section_count(file->handle, &count) != LDPS_OK)
+ return LDPS_ERR;
+
+ for (unsigned i = 0; i < count; ++i)
+ {
+ struct ld_plugin_section section;
+ unsigned int type = 0;
+ char *name = NULL;
+ int position = 3;
+
+ section.handle = file->handle;
+ section.shndx = i;
+
+ if (get_input_section_type(section, &type) != LDPS_OK)
+ return LDPL_FATAL;
+ if (type != SHT_PROGBITS)
+ continue;
+
+ if (get_input_section_name(section, &name))
+ return LDPL_FATAL;
+
+ /* As in plugin_section_order.c, order is foo() followed by bar()
+ followed by baz() */
+ if (is_prefix_of(".text.", name))
+ {
+ if (strstr(name, "_Z3foov") != NULL)
+ position = 0;
+ else if (strstr(name, "_Z3barv") != NULL)
+ position = 1;
+ else if (strstr(name, "_Z3bazv") != NULL)
+ position = 2;
+ else
+ position = 3;
+ }
+ if (position < 3)
+ {
+ section_list[position] = section;
+ num_entries++;
+ }
+ }
+
+ if (num_entries != 3)
+ return LDPL_FATAL;
+
+ update_section_order(section_list, num_entries);
+ unique_segment_for_sections (".text.plugin_created_unique", 0, 0x1000,
+ section_list, num_entries);
+
+ return LDPS_OK;
+}
--
2.14.1