[PATCH 5/8 v2] gen-perf-test: parallel build support

[Doug Evans <xdje42 at gmail dot com>]

Hi.

This patch is v2 of this patch:
https://sourceware.org/ml/gdb-patches/2015-07/msg00589.html

Regression tested for real this time.
The change is to the leave the default handling as setting
GDB_PARALLEL to "yes" instead of a subdirectory name,
and then having one function that computes the path to use,
and then have everyone call it.

2015-07-26  Doug Evans  <dje@google.com>

	* Makefile.in (workers/%.worker, build-perf): New rule.
	(GDB_PERFTEST_MODE): New variable.
	(check-perf): Use it.
	(clean): Clean up gdb.perf parallel build subdirs.
	* lib/build-piece.exp: New file.
	* lib/gdb.exp (make_gdb_parallel_path): New function
	(standard_output_file, standard_temp_file): Call it.
	(GDB_PARALLEL handling): Make outputs,temp,cache directories as subdirs
	of $GDB_PARALLEL.
	* lib/cache.exp (gdb_do_cache): Call make_gdb_parallel_path.

diff --git a/gdb/testsuite/Makefile.in b/gdb/testsuite/Makefile.in
index c064f06..3ad5feb 100644
--- a/gdb/testsuite/Makefile.in
+++ b/gdb/testsuite/Makefile.in
@@ -234,9 +234,41 @@ check/no-matching-tests-found:
 	@echo "No matching tests found."
 	@echo ""
 
+# Utility rule invoked by step 2 of the build-perf rule.
+@GMAKE_TRUE@workers/%.worker:
+@GMAKE_TRUE@	mkdir -p gdb.perf/outputs/$*
+@GMAKE_TRUE@	$(DO_RUNTEST) --status --outdir=gdb.perf/outputs/$* lib/build-piece.exp WORKER=$* GDB_PARALLEL=gdb.perf $(RUNTESTFLAGS) GDB_PERFTEST_MODE=compile GDB_PERFTEST_SUBMODE=build-pieces
+
+# Utility rule to build tests that support it in parallel.
+# The build is broken into 3 steps distinguished by GDB_PERFTEST_SUBMODE:
+# gen-workers, build-pieces, final.
+#
+# GDB_PERFTEST_MODE appears *after* RUNTESTFLAGS here because we don't want
+# anything in RUNTESTFLAGS to override it.
+#
+# We don't delete the outputs directory here as these programs can take
+# awhile to build, and perftest.exp has support for deciding whether to
+# recompile them.  If you want to remove these directories, make clean.
+#
+# The point of step 1 is to construct the set of worker tasks for step 2.
+# All of the information needed by build-piece.exp is contained in the name
+# of the generated .worker file.
+@GMAKE_TRUE@build-perf: $(abs_builddir)/site.exp
+@GMAKE_TRUE@	rm -rf gdb.perf/workers
+@GMAKE_TRUE@	mkdir -p gdb.perf/workers
+@GMAKE_TRUE@	@: Step 1: Generate the build .worker files.
+@GMAKE_TRUE@	$(DO_RUNTEST) --status --directory=gdb.perf --outdir gdb.perf/workers GDB_PARALLEL=gdb.perf $(RUNTESTFLAGS) GDB_PERFTEST_MODE=compile GDB_PERFTEST_SUBMODE=gen-workers
+@GMAKE_TRUE@	@: Step 2: Compile the pieces.  Here is the build parallelism.
+@GMAKE_TRUE@	$(MAKE) $$(cd gdb.perf && echo workers/*/*.worker)
+@GMAKE_TRUE@	@: Step 3: Do the final link.
+@GMAKE_TRUE@	$(DO_RUNTEST) --status --directory=gdb.perf --outdir gdb.perf GDB_PARALLEL=gdb.perf $(RUNTESTFLAGS) GDB_PERFTEST_MODE=compile GDB_PERFTEST_SUBMODE=final
+
+# The default is to both compile and run the tests.
+GDB_PERFTEST_MODE = both
+
 check-perf: all $(abs_builddir)/site.exp
 	@if test ! -d gdb.perf; then mkdir gdb.perf; fi
-	$(DO_RUNTEST) --directory=gdb.perf --outdir gdb.perf GDB_PERFTEST_MODE=both $(RUNTESTFLAGS)
+	$(DO_RUNTEST) --directory=gdb.perf --outdir gdb.perf GDB_PERFTEST_MODE=$(GDB_PERFTEST_MODE) $(RUNTESTFLAGS)
 
 force:;
 
@@ -245,6 +277,7 @@ clean mostlyclean:
 	-rm -f core.* *.tf *.cl tracecommandsscript copy1.txt zzz-gdbscript
 	-rm -f *.dwo *.dwp
 	-rm -rf outputs temp cache
+	-rm -rf gdb.perf/workers gdb.perf/outputs gdb.perf/temp gdb.perf/cache
 	-rm -f read1.so expect-read1
 	if [ x"${ALL_SUBDIRS}" != x ] ; then \
 	    for dir in ${ALL_SUBDIRS}; \
diff --git a/gdb/testsuite/lib/build-piece.exp b/gdb/testsuite/lib/build-piece.exp
new file mode 100644
index 0000000..a81530c
--- /dev/null
+++ b/gdb/testsuite/lib/build-piece.exp
@@ -0,0 +1,39 @@
+# Copyright (C) 2014 Free Software Foundation, Inc.
+
+# 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, see <http://www.gnu.org/licenses/>.
+
+# Utility to bootstrap building a piece of a performance test in a
+# parallel build.
+# See testsuite/Makefile.in:workers/%.worker.
+# WORKER is set by the makefile and is
+# "{program_name}/{program_name}-{worker_nr}".
+
+regexp "^\(.+\)/\(.+\)-\(\[0-9\]+\)$" $WORKER entire_match PROGRAM_NAME pname2 WORKER_NR
+
+if { ![info exists entire_match] || $entire_match != $WORKER } {
+    error "Bad value for WORKER: $WORKER"
+}
+if { $PROGRAM_NAME != $pname2 } {
+    error "Bad value for WORKER: $WORKER"
+}
+
+# $subdir is set to "lib", because that is where this file lives,
+# which is not what tests expect.
+set subdir "gdb.perf"
+
+# $gdb_test_file_name is set to this file, build-piece, which is not what
+# tests expect.
+set gdb_test_file_name $PROGRAM_NAME
+
+source $srcdir/$subdir/${gdb_test_file_name}.exp
diff --git a/gdb/testsuite/lib/cache.exp b/gdb/testsuite/lib/cache.exp
index 8df04b9..968e9ff 100644
--- a/gdb/testsuite/lib/cache.exp
+++ b/gdb/testsuite/lib/cache.exp
@@ -35,7 +35,7 @@ proc gdb_do_cache {name} {
     }
 
     if {[info exists GDB_PARALLEL]} {
-	set cache_filename [file join $objdir cache $cache_name]
+	set cache_filename [make_gdb_parallel_path cache $cache_name]
 	if {[file exists $cache_filename]} {
 	    set fd [open $cache_filename]
 	    set gdb_data_cache($cache_name) [read -nonewline $fd]
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index c5cfa4b..ecfc863 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -3972,6 +3972,26 @@ proc default_gdb_init { test_file_name } {
     }
 }
 
+# Return a path using GDB_PARALLEL.
+# ARGS is a list of path elements to append to "$objdir/$GDB_PARALLEL".
+# GDB_PARALLEL must be defined, the caller must check.
+#
+# The default value for GDB_PARALLEL is, canonically, ".".
+# The catch is that tests don't expect an additional "./" in file paths so
+# omit any directory for the default case.
+# GDB_PARALLEL is written as "yes" for the default case in Makefile.in to mark
+# its special handling.
+
+proc make_gdb_parallel_path { args } {
+    global GDB_PARALLEL objdir
+    set joiner [list "file" "join" $objdir]
+    if { $GDB_PARALLEL != "yes" } {
+	lappend joiner $GDB_PARALLEL
+    }
+    set joiner [concat $joiner $args]
+    return [eval $joiner]
+}
+
 # Turn BASENAME into a full file name in the standard output
 # directory.  It is ok if BASENAME is the empty string; in this case
 # the directory is returned.
@@ -3980,7 +4000,7 @@ proc standard_output_file {basename} {
     global objdir subdir gdb_test_file_name GDB_PARALLEL
 
     if {[info exists GDB_PARALLEL]} {
-	set dir [file join $objdir outputs $subdir $gdb_test_file_name]
+	set dir [make_gdb_parallel_path outputs $subdir $gdb_test_file_name]
 	file mkdir $dir
 	return [file join $dir $basename]
     } else {
@@ -3994,7 +4014,7 @@ proc standard_temp_file {basename} {
     global objdir GDB_PARALLEL
 
     if {[info exists GDB_PARALLEL]} {
-	return [file join $objdir temp $basename]
+	return [make_gdb_parallel_path temp $basename]
     } else {
 	return $basename
     }
@@ -5119,7 +5139,10 @@ if {[info exists GDB_PARALLEL]} {
     if {[is_remote host]} {
 	unset GDB_PARALLEL
     } else {
-	file mkdir outputs temp cache
+	file mkdir \
+	    [make_gdb_parallel_path outputs] \
+	    [make_gdb_parallel_path temp] \
+	    [make_gdb_parallel_path cache]
     }
 }