At last! MSVC precompiles headers and can use them.

backends.py

@@ -182,8 +182,8 @@ class Backend():
             if len(p) == 0:
                 continue
             if compiler.can_compile(p[-1]):
-                args.append('-include')
-                args.append(os.path.split(p[0])[-1])
+                header = p[0]
+                args += compiler.get_pch_use_args(pchpath, header)
         if len(args) > 0:
             args = [includearg] + args
         return args
@@ -633,10 +633,8 @@ class NinjaBackend(Backend):
             pch_dep = []
         else:
             arr = []
-            for pch in pchlist:
-                i = os.path.join(self.get_target_private_dir(target),
-                                  os.path.split(pch)[-1] + '.' + compiler.get_pch_suffix())
-                arr.append(i)
+            i = os.path.join(self.get_target_private_dir(target), compiler.get_pch_name(pchlist[0]))
+            arr.append(i)
             pch_dep = arr
         for i in target.get_include_dirs():
             basedir = i.get_curdir()
@@ -666,9 +664,7 @@ class NinjaBackend(Backend):
             raise RuntimeError('MSVC requires one header and one source to produce precompiled headers.')
         header = pch[0]
         source = pch[1]
-        chopped = os.path.split(header)[-1].split('.')[:-1]
-        chopped.append(compiler.get_pch_suffix())
-        pchname = '.'.join(chopped)
+        pchname = compiler.get_pch_name(header)
         dst = os.path.join(self.get_target_private_dir(target), pchname)
 
         commands = []

environment.py

@@ -93,7 +93,13 @@ class CCompiler():
 
     def name_string(self):
         return ' '.join(self.exelist)
-    
+
+    def get_pch_use_args(self, pch_dir, header):
+        return ['-include', os.path.split(header)[-1]]
+
+    def get_pch_name(self, header_name):
+        return os.path.split(header_name)[-1] + '.' + self.get_pch_suffix()
+
     def sanity_check(self, work_dir):
         source_name = os.path.join(work_dir, 'sanitycheckc.c')
         binary_name = os.path.join(work_dir, 'sanitycheckc')
@@ -251,6 +257,17 @@ class VisualStudioCCompiler(CCompiler):
     
     def get_pch_suffix(self):
         return 'pch'
+    
+    def get_pch_name(self, header):
+        chopped = os.path.split(header)[-1].split('.')[:-1]
+        chopped.append(self.get_pch_suffix())
+        pchname = '.'.join(chopped)
+        return pchname
+
+    def get_pch_use_args(self, pch_dir, header):
+        base = os.path.split(header)[-1]
+        pchname = self.get_pch_name(header)
+        return ['/FI' + base, '/Yu' + base, '/Fp' + os.path.join(pch_dir, pchname)]
 
     def get_debug_flags(self):
         return ['/D_DEBUG', '/Zi', '/MDd', '/Ob0', '/RTC1']

test cases/common/13 pch/prog.c

@@ -1,6 +1,4 @@
-#if defined(_MSC_VER)
-#include"prog.pch"
-#endif
+// No includes here, they need to come from the PCH
 
 void func() {
     fprintf(stdout, "This is a function that fails if stdio is not #included.\n");
@@ -9,3 +7,4 @@ void func() {
 int main(int argc, char **argv) {
     return 0;
 }
+