[SCons] Use precompiled header to speed up compilation with MSVC

Update Appveyor config to turn off debug info so PCH can be used

SConstruct

@@ -61,6 +61,8 @@ if 'clean' in COMMAND_LINE_TARGETS:
     removeFile('.sconsign.dblite')
     removeFile('include/cantera/base/config.h')
     removeFile('include/cantera/base/system.h.gch')
+    removeFile('include/cantera/base/system.pch')
+    removeFile('include/cantera/base/system.obj')
     removeDirectory('include/cantera/ext')
     removeFile('interfaces/cython/cantera/_cantera.cpp')
     removeFile('interfaces/cython/cantera/_cantera.h')
@@ -268,6 +270,8 @@ elif env['CC'] == 'cl': # Visual Studio
     defaults.optimizeCcFlags = '/O2'
     defaults.debugLinkFlags = '/DEBUG'
     defaults.warningFlags = '/W3'
+    defaults.buildPch = True
+    env['pch_flags'] = ['/FIcantera/base/system.h']
 
 elif 'icc' in env.subst('$CC'):
     defaults.cxxFlags = '-std=c++0x'
@@ -1407,15 +1411,6 @@ 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')
 

appveyor.yml

@@ -6,7 +6,7 @@ install:
     C:\Python27-x64\Scripts\pip.exe install cython
 
 build_script:
-- cmd: C:\Python27-x64\scons build boost_inc_dir=C:\Libraries\boost_1_62_0
+- cmd: C:\Python27-x64\scons build boost_inc_dir=C:\Libraries\boost_1_62_0 debug=n
 
 test_script:
 - ps: |

include/cantera/base/system.cpp

@@ -0,0 +1 @@
+#include "cantera/base/system.h"

src/SConscript

@@ -24,18 +24,38 @@ libs = [('base', ['cpp'], baseSetup),
         ('clib', ['cpp'], defaultSetup),
         ]
 
+localenv = env.Clone()
+localenv.Prepend(CPPPATH=[Dir('#include'), Dir('#include/cantera/ext'), Dir('.')])
+localenv.Append(CCFLAGS=env['warning_flags'])
+
+if env['CC'] == 'cl' and env['debug']:
+    env['use_pch'] = False # PCH doesn't work with per-file PDB
+
+if env['use_pch']:
+    if env['CC'] == 'cl':
+        localenv['PCH'], pchobj = localenv.PCH('#include/cantera/base/system.cpp')
+        libraryTargets.append(pchobj)
+        localenv['PCHSTOP'] = 'cantera/base/system.h'
+    else:
+        localenv['precompiled_header'] = File('#include/cantera/base/system.h')
+        pch = build(localenv.GchSh('#include/cantera/base/system.h.gch',
+                              localenv['precompiled_header']))
+        # To force early compilaton of the precompiled header
+        localenv.Depends(env['config_h_target'], pch)
+
+else:
+    removeFile('include/cantera/base/system.h.gch')
+    env['pch_flags'] = []
+
 for subdir, extensions, setup in libs:
-    localenv = env.Clone()
-    localenv.Prepend(CPPPATH=[Dir('#include'), Dir('#include/cantera/ext')])
-    localenv.Append(CCFLAGS=env['warning_flags'])
-    source = setup(localenv, subdir, extensions)
-    objects = localenv.SharedObject(source)
-    localenv.Depends(objects, localenv['config_h_target'])
+    env2 = localenv.Clone()
+    source = setup(env2, subdir, extensions)
+    objects = env2.SharedObject(source)
+    env2.Depends(objects, env2['config_h_target'])
     libraryTargets.extend(objects)
 
 
 # build the Cantera static library
-localenv = env.Clone()
 lib = build(localenv.StaticLibrary('../lib/cantera', libraryTargets,
                                    SPAWN=getSpawn(localenv)))
 localenv.Depends(lib, localenv['config_h_target'])