Build System Improvements

SConstruct

@@ -8,13 +8,18 @@ from typing import List, Union
 
 import SCons
 
+_SCRIPTS_DIR = Dir(".").abspath
+if _SCRIPTS_DIR not in sys.path:
+    sys.path.insert(0, _SCRIPTS_DIR)
+
 # Local
 from build.option_handler import OptionsClass
 from build.glob_recursive import GlobRecursive
 from build.git_info import get_git_info, git_builder
 from build.license_info import license_builder
 from build.author_info import author_builder
 from build.cache import show_progress
+from build.pch import setup_pch
 
 def normalize_path(val, env):
     return val if os.path.isabs(val) else os.path.join(env.Dir("#").abspath, val)
@@ -167,9 +172,14 @@ def SetupOptions():
         )
     )
 
-    # Add platform options
+    # Add platform options. Iterate deterministically with the current platform
+    # registered last so its defaults win 
     tools = {}
-    for pl in set(platforms) - set(unsupported_known_platforms):
+    current_platform = env.get("platform", default_platform)
+    supported = sorted(set(platforms) - set(unsupported_known_platforms))
+    if current_platform in supported:
+        supported = [pl for pl in supported if pl != current_platform] + [current_platform]
+    for pl in supported:
         tool = Tool(pl, toolpath=env.TOOLPATH)
         if hasattr(tool, "options"):
             tool.options(opts)
@@ -205,6 +215,7 @@ def SetupOptions():
     opts.Add(BoolVariable("verbose", "Enable verbose output for the compilation", False))
     opts.Add(BoolVariable("intermediate_delete", "Enables automatically deleting unassociated intermediate binary files.", True))
     opts.Add(BoolVariable("progress", "Show a progress indicator during compilation", True))
+    opts.Add(BoolVariable("use_pch", "Enable precompiled headers when the toolchain supports it", True))
 
     # Targets flags tool (optimizations, debug symbols)
     target_tool = Tool("targets", toolpath=env.TOOLPATH)
@@ -261,10 +272,11 @@ def FinalizeOptions():
     target_tool.generate(env)
     tool.generate(env)
 
+    Decider("MD5-timestamp")
+
     scons_cache_path = os.environ.get("SCONS_CACHE")
     if scons_cache_path != None:
         CacheDir(scons_cache_path)
-        Decider("MD5")
         print("Scons cache enabled... (path: '" + scons_cache_path + "')")
 
     if env["compiledb"] and is_standalone:
@@ -279,6 +291,7 @@ env.get_git_info = get_git_info
 env.license_builder = license_builder
 env.git_builder = git_builder
 env.author_builder = author_builder
+env.SetupPCH = lambda header, source: setup_pch(env, header, source)
 
 
 def to_raw_cstring(value: Union[str, List[str]]) -> str:

build/glob_recursive.py

@@ -1,5 +1,6 @@
 def GlobRecursive(pattern, nodes=["."], exclude=None):
     import fnmatch
+    import os
 
     import SCons
 
@@ -11,15 +12,20 @@ def GlobRecursive(pattern, nodes=["."], exclude=None):
 
     results = []
     for node in nodes:
-        nnodes = []
-        for f in Glob(str(node) + "/*", source=True):
+        node_str = str(node)
+
+        for f in Glob(node_str + "/*", source=True):
             if type(f) is SCons.Node.FS.Dir:
-                nnodes.append(f)
-        results += GlobRecursive(pattern, nnodes)
-        results += Glob(str(node) + "/" + pattern, source=True)
-        if isinstance(exclude, list):
-            for val in results:
-                for pat in exclude:
-                    if fnmatch.fnmatch(str(val), pat):
-                        results.remove(val)
+                child = node_str + "/" + os.path.basename(str(f))
+                results += GlobRecursive(pattern, [child])
+
+        results += Glob(node_str + "/" + pattern)
+
+    if isinstance(exclude, list):
+
+        def norm(s):
+            return str(s).replace("\\", "/")
+
+        norm_exclude = [norm(p) for p in exclude]
+        results = [r for r in results if not any(fnmatch.fnmatch(norm(r), p) for p in norm_exclude)]
     return results

build/pch.py

@@ -0,0 +1,25 @@
+def setup_pch(env, header_rel, source_cpp_variant):
+    if not env.get("use_pch", True):
+        return
+
+    handler = _select_handler(env)
+    if handler is None:
+        return
+
+    name = handler(env, header_rel, source_cpp_variant)
+    print(f"[PCH] enabled ({name}): {header_rel}")
+
+
+def _select_handler(env):
+    if env.get("is_msvc", False):
+        return _msvc_pch
+    # TODO: GCC/Clang/MinGW
+    return None
+
+
+def _msvc_pch(env, header_rel, source_cpp_variant):
+    env["PCHSTOP"] = header_rel
+    pch_pch, _pch_obj = env.PCH(source_cpp_variant)
+    env["PCH"] = pch_pch
+    env.Append(CCFLAGS=["/FI" + header_rel])
+    return "msvc"