Add first test for GHC API features.

testsuite/tests/ghc-regress/ghc-api/Makefile

+TOP=../../..
+include $(TOP)/mk/boilerplate.mk
+include $(TOP)/mk/test.mk

testsuite/tests/ghc-regress/ghc-api/apirecomp001/A.hs

+{-# OPTIONS_GHC -Wall #-}
+module A where
+
+import B
+import System.IO
+
+main = do
+    print answer_to_live_the_universe_and_everything
+    hFlush stdout

testsuite/tests/ghc-regress/ghc-api/apirecomp001/B.hs

+{-# OPTIONS_GHC -Wall #-}
+module B where
+
+answer_to_live_the_universe_and_everything =
+    length [1..23*2] - 4
\ No newline at end of file

testsuite/tests/ghc-regress/ghc-api/apirecomp001/Makefile

+TOP=../../../..
+include $(TOP)/mk/boilerplate.mk
+include $(TOP)/mk/test.mk
+
+clean:
+	@rm -f *.o *.hi
+
+apirecomp001: clean
+	@$(TEST_HC) --make -v0 -package ghc myghc.hs
+	@myghc $(TOP)/..

testsuite/tests/ghc-regress/ghc-api/apirecomp001/all.T

+test('apirecomp001', skip_if_fast, run_command, ['$MAKE -s --no-print-directory apirecomp001'])

testsuite/tests/ghc-regress/ghc-api/apirecomp001/apirecomp001.stdout

+True
+True
+target nothing: ok
+True
+True
+target interpreted: ok
+42
+ok

testsuite/tests/ghc-regress/ghc-api/apirecomp001/myghc.hs

+-- 1. Load a set of modules with "nothing" target
+-- 2. Load it again with "interpreted" target
+-- 3. Execute some code
+--    a. If the recompilation checker is buggy this will die due to missing
+--       code
+--    b. If it's correct, it will recompile because the target has changed.
+--
+-- This program must be called with GHC's libdir as the single command line
+-- argument.
+module Main where
+
+import GHC
+import MonadUtils ( MonadIO(..) )
+import BasicTypes ( failed )
+import Bag        ( bagToList )
+import System.Environment
+import Control.Monad
+import System.IO
+
+main = do
+  [libdir] <- getArgs
+  runGhc (Just libdir) $ do
+    dflags <- getSessionDynFlags
+    setSessionDynFlags $ dflags { hscTarget = HscNothing
+                                , ghcLink  = LinkInMemory
+                                , verbosity = 0 -- silence please
+                                }
+    root_mod <- guessTarget "A.hs" Nothing
+    setTargets [root_mod]
+    ok <- loadWithLogger myLogger LoadAllTargets
+    when (failed ok) $ error "Couldn't load A.hs in nothing mode"
+    prn "target nothing: ok"
+
+    dflags <- getSessionDynFlags
+    setSessionDynFlags $ dflags { hscTarget = HscInterpreted }
+    ok <- loadWithLogger myLogger LoadAllTargets
+    when (failed ok) $ error "Couldn't load A.hs in interpreted mode"
+    prn "target interpreted: ok"
+
+    -- set context to module "A"
+    mg <- getModuleGraph
+    let [mod] = [ ms_mod m | m <- mg, moduleNameString (ms_mod_name m) == "A" ]
+    setContext [mod] []
+    liftIO $ hFlush stdout  -- make sure things above are printed before
+                            -- interactive output
+    r <- runStmt "main" RunToCompletion
+    case r of
+      RunOk _        -> prn "ok"
+      RunFailed      -> prn "compilation failed"
+      RunException _ -> prn "exception"
+      RunBreak _ _ _ -> prn "breakpoint"
+    liftIO $ hFlush stdout
+    return ()
+
+-- prints number of warnings; this is our indicator for recompilation.  We ignore
+-- the number of warnings since this might change, however, there should always
+-- be at least one.
+myLogger _ = do 
+  ws <- getWarnings 
+  clearWarnings
+  liftIO $ print (length (bagToList ws) > 0)
+
+prn :: MonadIO m => String -> m ()
+prn = liftIO . putStrLn
\ No newline at end of file