1 files changed, 83 insertions, 0 deletions
diff --git a/hadrian/src/Rules/Compile.hs b/hadrian/src/Rules/Compile.hs
new file mode 100644
index 0000000000..4e85db2df6
--- /dev/null
+++ b/hadrian/src/Rules/Compile.hs
@@ -0,0 +1,83 @@
+module Rules.Compile (compilePackage) where
+
+import Hadrian.Oracles.TextFile
+
+import Base
+import Context
+import Expression
+import Rules.Generate
+import Target
+import Utilities
+
+compilePackage :: [(Resource, Int)] -> Context -> Rules ()
+compilePackage rs context@Context {..} = do
+    root <- buildRootRules
+    let dir             = root -/- buildDir context
+        nonHs extension = dir -/- extension <//> "*" <.> osuf way
+        compile compiler obj2src obj = do
+            src <- obj2src context obj
+            need [src]
+            needDependencies context src $ obj <.> "d"
+            buildWithResources rs $ target context (compiler stage) [src] [obj]
+        compileHs = \[obj, _hi] -> do
+            path <- contextPath context
+            (src, deps) <- lookupDependencies (path -/- ".dependencies") obj
+            need $ src : deps
+            needLibrary =<< contextDependencies context
+            buildWithResources rs $ target context (Ghc CompileHs stage) [src] [obj]
+
+    priority 2.0 $ do
+        nonHs "c"   %> compile (Ghc CompileCWithGhc) (obj2src "c"   $ const False     )
+        nonHs "cmm" %> compile (Ghc CompileHs)       (obj2src "cmm" isGeneratedCmmFile)
+        nonHs "s"   %> compile (Ghc CompileHs)       (obj2src "S"   $ const False     )
+
+    -- TODO: Add dependencies for #include of .h and .hs-incl files (gcc -MM?).
+    [ dir <//> "*" <.> suf way | suf <- [    osuf,     hisuf] ] &%> compileHs
+    [ dir <//> "*" <.> suf way | suf <- [obootsuf, hibootsuf] ] &%> compileHs
+
+-- | Discover dependencies of a given source file by iteratively calling @gcc@
+-- in the @-MM -MG@ mode and building generated dependencies if they are missing
+-- until reaching a fixed point.
+needDependencies :: Context -> FilePath -> FilePath -> Action ()
+needDependencies context@Context {..} src depFile = discover
+  where
+    discover = do
+        build $ target context (Cc FindCDependencies stage) [src] [depFile]
+        deps <- parseFile depFile
+        -- Generated dependencies, if not yet built, will not be found and hence
+        -- will be referred to simply by their file names.
+        let notFound = filter (\file -> file == takeFileName file) deps
+        -- We find the full paths to generated dependencies, so we can request
+        -- to build them by calling 'need'.
+        todo <- catMaybes <$> mapM (fullPathIfGenerated context) notFound
+
+        if null todo
+        then need deps -- The list of dependencies is final, need all
+        else do
+            need todo  -- Build newly discovered generated dependencies
+            discover   -- Continue the discovery process
+
+    parseFile :: FilePath -> Action [String]
+    parseFile file = do
+        input <- liftIO $ readFile file
+        case parseMakefile input of
+            [(_file, deps)] -> return deps
+            _               -> return []
+
+-- | Find a given 'FilePath' in the list of generated files in the given
+-- 'Context' and return its full path.
+fullPathIfGenerated :: Context -> FilePath -> Action (Maybe FilePath)
+fullPathIfGenerated context file = interpretInContext context $ do
+    generated <- generatedDependencies
+    return $ find ((== file) . takeFileName) generated
+
+obj2src :: String -> (FilePath -> Bool) -> Context -> FilePath -> Action FilePath
+obj2src extension isGenerated context@Context {..} obj
+    | isGenerated src = return src
+    | otherwise       = (pkgPath package ++) <$> suffix
+  where
+    src    = obj -<.> extension
+    suffix = do
+        path <- buildPath context
+        return $ fromMaybe ("Cannot determine source for " ++ obj)
+               $ stripPrefix (path -/- extension) src