[SCons] Use precompiled header to speed up compilation with GCC/Clang

.gitignore

@@ -9,6 +9,7 @@ build/
 test/work/
 interfaces/cython/cantera/_cantera.h
 include/cantera/base/config.h
+include/cantera/base/system.h.gch
 include/cantera/ext/
 interfaces/matlab/ctpath.m
 interfaces/matlab/Contents.m

SConstruct

@@ -60,6 +60,7 @@ if 'clean' in COMMAND_LINE_TARGETS:
     removeDirectory('.sconf_temp')
     removeFile('.sconsign.dblite')
     removeFile('include/cantera/base/config.h')
+    removeFile('include/cantera/base/system.h.gch')
     removeDirectory('include/cantera/ext')
     removeFile('interfaces/cython/cantera/_cantera.cpp')
     removeFile('interfaces/cython/cantera/_cantera.h')
@@ -180,7 +181,7 @@ if os.name == 'nt':
 else:
     toolchain = ['default']
 
-env = Environment(tools=toolchain+['textfile', 'subst', 'recursiveInstall', 'wix'],
+env = Environment(tools=toolchain+['textfile', 'subst', 'recursiveInstall', 'wix', 'gch'],
                   ENV={'PATH': os.environ['PATH']},
                   toolchain=toolchain,
                   **extraEnvArgs)
@@ -245,6 +246,8 @@ defaults.noDebugCcFlags = ''
 defaults.debugLinkFlags = ''
 defaults.noDebugLinkFlags = ''
 defaults.warningFlags = '-Wall'
+defaults.buildPch = False
+env['pch_flags'] = []
 
 if 'gcc' in env.subst('$CC'):
     defaults.optimizeCcFlags += ' -Wno-inline'
@@ -253,6 +256,8 @@ if 'gcc' in env.subst('$CC'):
         defaults.cxxFlags = '-std=gnu++0x'
     else:
         defaults.cxxFlags = '-std=c++0x'
+    defaults.buildPch = True
+    env['pch_flags'] = ['-include', 'include/cantera/base/system.h']
 
 elif env['CC'] == 'cl': # Visual Studio
     defaults.cxxFlags = ['/EHsc']
@@ -272,6 +277,8 @@ elif 'icc' in env.subst('$CC'):
 elif 'clang' in env.subst('$CC'):
     defaults.ccFlags = '-fcolor-diagnostics'
     defaults.cxxFlags = '-std=c++11'
+    defaults.buildPch = True
+    env['pch_flags'] = ['-include-pch', 'include/cantera/base/system.h.gch']
 
 else:
     print "WARNING: Unrecognized C compiler '%s'" % env['CC']
@@ -473,6 +480,9 @@ config_options = [
         string "all" or a comma separated list of variable names, e.g.
         'LD_LIBRARY_PATH,HOME'.""",
      defaults.env_vars),
+    BoolVariable(
+        'use_pch', """Use a precompiled-header to speed up compilation""",
+        defaults.buildPch),
     ('cxx_flags',
      """Compiler flags passed to the C++ compiler only. Separate multiple
         options with spaces, e.g. cxx_flags='-g -Wextra -O3 --std=c++11'""",
@@ -1298,6 +1308,7 @@ config_h = env.Command('include/cantera/base/config.h',
                        'include/cantera/base/config.h.in',
                        ConfigBuilder(configh))
 env.AlwaysBuild(config_h)
+
 env['config_h_target'] = config_h
 
 # *********************
@@ -1396,6 +1407,15 @@ env['cantera_shared_libs'] = linkSharedLibs
 if not env['renamed_shared_libraries']:
     env['cantera_shared_libs'] = linkLibs
 
+if env['use_pch']:
+    env['precompiled_header'] = File('include/cantera/base/system.h')
+    pch = build(env.GchSh('include/cantera/base/system.h.gch', env['precompiled_header']))
+    # To force early compilaton of the precompiled header
+    env.Depends(config_h, pch)
+else:
+    removeFile('include/cantera/base/system.h.gch')
+    env['pch_flags'] = []
+
 # Add targets from the SConscript files in the various subdirectories
 Export('env', 'build', 'libraryTargets', 'install', 'buildSample')
 

include/cantera/base/system.h

@@ -0,0 +1,19 @@
+#ifndef CT_SYSTEM_H
+#define CT_SYSTEM_H
+
+// commonly-included system headers
+#include <cmath>
+#include <cstdio>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <cstdlib>
+#include <vector>
+#include <map>
+#include <string>
+#include <algorithm>
+#include <memory>
+
+#include <boost/algorithm/string.hpp>
+
+#endif

site_scons/site_tools/gch.py

@@ -0,0 +1,155 @@
+#
+# SCons builder for gcc's precompiled headers
+# Copyright (C) 2006  Tim Blechmann (C) 2011 Pedro Larroy (C) 2015 Carl Cerecke
+#
+# 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 2 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; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+# 1.3
+#
+# 09-11-2011 Pedro Larroy: Fixed dependency emitter not working with variant dir
+# 07-09-2012 Pedro Larroy: Create the resulting pch on the variant directory,
+#   the variant dir should be added to the includes, before any of the other
+#   local includes for the compiler to search the pch file on the build directory
+#   that we just created. In doubt execute 'strace -f g++ ...' to check that it
+#   opens the correct pch.
+# 2015-08-07 Carl Cerecke: Hack to work around corruption of .sconsign.dblite
+#   caused by SCons.Scanner.C.CScanner() when using both variant dirs, and also
+#   separate non-gch static libraries which depend on generated c++ source files.
+#   Instead of using SCons.Scanner.C.CScanner, use our own hack.
+#
+# FIXME: the original precompiled header has to be set
+#   in the environment as
+#   env['precompiled_header'], this should be fixed
+#
+#
+#  env['precompiled_header'] = File('src/common/includes/all.h')
+#  env['Gch'] = env.Gch(target='common/includes/all.h.gch', source=env['precompiled_header'])
+
+
+
+import SCons.Action
+import SCons.Builder
+import SCons.Scanner.C
+import SCons.Util
+import SCons.Script
+import os
+import functools
+import re
+import subprocess
+
+SCons.Script.EnsureSConsVersion(0,96,92)
+
+GchAction = SCons.Action.Action('$GCHCOM', '$GCHCOMSTR')
+GchShAction = SCons.Action.Action('$GCHSHCOM', '$GCHSHCOMSTR')
+
+def gen_suffix(env, sources):
+    return sources[0].get_suffix() + env['GCHSUFFIX']
+
+GchShBuilder = SCons.Builder.Builder(action = GchShAction,
+                                     source_scanner = SCons.Scanner.C.CScanner(),
+                                     suffix = gen_suffix)
+
+GchBuilder = SCons.Builder.Builder(action = GchAction,
+                                   source_scanner = SCons.Scanner.C.CScanner(),
+                                   suffix = gen_suffix)
+
+def header_path(node):
+    h_path = node.abspath
+    idx = h_path.rfind('.gch')
+    if idx != -1:
+        h_path = h_path[0:idx]
+        if not os.path.isfile(h_path):
+            raise SCons.Errors.StopError("can't find header file: {0}".format(h_path))
+        return h_path
+
+    else:
+        raise SCons.Errors.StopError("{0} file doesn't have .gch extension".format(h_path))
+
+def dump_node(node):
+    print '~Attrs for '+str(node)
+    for attr_name in sorted(dir(node)):
+        if attr_name[0] == '_':
+            continue
+        attr = getattr(node, attr_name)
+        if type(attr) == list:
+            attr = [str(x) for x in attr]
+        if not callable(attr):
+            print '~',attr_name+":", attr
+
+
+inc_re = re.compile(r'#include\s*"([a-zA-Z0-9._]+)"')
+def _directly_includes_header(node, header):
+    '''
+    Simple file search.
+    Using SCons.Scanner.C.CScanner with variant_dir can cause corruption of .SConsign.dblite
+    and you will get messages during build like:
+    "scons: Cannot explain why `output/libGch1.o' is being rebuilt: No previous build information found"
+    '''
+    for line in open(str(node)):
+        if line.startswith('#include'):
+            match = inc_re.match(line)
+            if match:
+                fname = match.group(1)
+                if fname == header:
+                    return True
+            #return False # Should first #include should be precompiled header?
+    return False
+
+def pch_emitter(pch_env_key, target, source, env):
+    src = source[0].srcnode()
+
+    if not os.path.exists(str(src)):
+        return target, source
+
+    if env.get(pch_env_key):
+        if _directly_includes_header(src, os.path.basename(env['precompiled_header'].path)):
+            if 'explain' in env.GetOption('debug'):
+                print 'Found dep. on pch: ', source[0], ' -> ', env[pch_env_key]
+            env.Depends(target, env[pch_env_key])
+    return (target, source)
+
+def generate(env):
+    """
+    Add builders and construction variables for the Gch builder.
+    """
+    env.Append(BUILDERS = {
+        'gch': env.Builder(
+        action = GchAction,
+        suffix = 'gch',
+        target_factory = env.fs.File,
+        ),
+        'gchsh': env.Builder(
+        action = GchShAction,
+        target_factory = env.fs.File,
+        ),
+        })
+
+    try:
+        bld = env['BUILDERS']['Gch']
+        bldsh = env['BUILDERS']['GchSh']
+    except KeyError:
+        bld = GchBuilder
+        bldsh = GchShBuilder
+        env['BUILDERS']['Gch'] = bld
+        env['BUILDERS']['GchSh'] = bldsh
+
+    env['GCHCOM']     = '$CXX -Wall -o $TARGET -x c++-header -c $CXXFLAGS $CCFLAGS $_CCCOMCOM $SOURCE'
+    env['GCHSHCOM']   = '$CXX -o $TARGET -x c++-header -c $SHCXXFLAGS $SHCCFLAGS $_CCCOMCOM $SOURCE'
+    env['GCHSUFFIX']  = '.gch'
+
+
+def exists(env):
+    return env.Detect('g++')

src/SConscript

@@ -3,6 +3,7 @@ from buildutils import *
 Import('env', 'build', 'install', 'libraryTargets')
 
 def defaultSetup(env, subdir, extensions):
+    env.Append(CCFLAGS=env['pch_flags'])
     return mglob(env, subdir, *extensions)
 
 def baseSetup(env, subdir, extensions):