Add new driver test for use of outdated .o files

This is something that's quite important for the correctness of the
incremental build system and doesn't appear to be tested currently; this
test fails on my hashing branch, whereas all of the other (non-perf)
tests pass.

7 files changed, 61 insertions, 0 deletions

diff --git a/testsuite/tests/driver/recomp019/B1.hs b/testsuite/tests/driver/recomp019/B1.hs
new file mode 100644
index 0000000000..9943eab231
--- /dev/null
+++ b/testsuite/tests/driver/recomp019/B1.hs
@@ -0,0 +1,4 @@
+module B where
+
+x :: Int
+x = 2
diff --git a/testsuite/tests/driver/recomp019/B2.hs b/testsuite/tests/driver/recomp019/B2.hs
new file mode 100644
index 0000000000..bed169b09c
--- /dev/null
+++ b/testsuite/tests/driver/recomp019/B2.hs
@@ -0,0 +1,4 @@
+module B where
+
+x :: Int
+x = 12
diff --git a/testsuite/tests/driver/recomp019/C.hs b/testsuite/tests/driver/recomp019/C.hs
new file mode 100644
index 0000000000..365ddd9655
--- /dev/null
+++ b/testsuite/tests/driver/recomp019/C.hs
@@ -0,0 +1,4 @@
+module C where
+
+x :: Int
+x = 3
diff --git a/testsuite/tests/driver/recomp019/Main.hs b/testsuite/tests/driver/recomp019/Main.hs
new file mode 100644
index 0000000000..084ba0a49a
--- /dev/null
+++ b/testsuite/tests/driver/recomp019/Main.hs
@@ -0,0 +1,6 @@
+module Main where
+
+import qualified B
+import qualified C
+
+main = putStrLn $ show $ B.x + C.x
diff --git a/testsuite/tests/driver/recomp019/Makefile b/testsuite/tests/driver/recomp019/Makefile
new file mode 100644
index 0000000000..8e66f82abb
--- /dev/null
+++ b/testsuite/tests/driver/recomp019/Makefile
@@ -0,0 +1,26 @@
+TOP=../../..
+include $(TOP)/mk/boilerplate.mk
+include $(TOP)/mk/test.mk
+
+# Recompilation test for when .hi files are up to date but .o files are
+# not
+
+clean:
+	rm -f Main *.o *.hi B.hs
+
+recomp019: clean
+	cp B1.hs B.hs
+	echo 'first run'
+	'$(TEST_HC)' $(TEST_HC_OPTS) --make Main
+	./Main
+	
+	# Update B.hs
+	cp B2.hs B.hs
+	
+	# Update B.hi (but not B.o)
+	'$(TEST_HC)' $(TEST_HC_OPTS) --make B -fno-code -fwrite-interface
+	
+	# Recompile
+	echo 'second run'
+	'$(TEST_HC)' $(TEST_HC_OPTS) --make Main
+	./Main
diff --git a/testsuite/tests/driver/recomp019/all.T b/testsuite/tests/driver/recomp019/all.T
new file mode 100644
index 0000000000..9b2481eab1
--- /dev/null
+++ b/testsuite/tests/driver/recomp019/all.T
@@ -0,0 +1,6 @@
+# Recompilation test for when .hi files are up to date but .o files are
+# not
+
+test('recomp019',
+     [extra_files(['Main.hs', 'B1.hs', 'B2.hs', 'C.hs'])],
+     makefile_test, [])
diff --git a/testsuite/tests/driver/recomp019/recomp019.stdout b/testsuite/tests/driver/recomp019/recomp019.stdout
new file mode 100644
index 0000000000..f1e4cd4d73
--- /dev/null
+++ b/testsuite/tests/driver/recomp019/recomp019.stdout
@@ -0,0 +1,11 @@
+first run
+[1 of 3] Compiling B                ( B.hs, B.o )
+[2 of 3] Compiling C                ( C.hs, C.o )
+[3 of 3] Compiling Main             ( Main.hs, Main.o )
+Linking Main ...
+5
+[1 of 1] Compiling B                ( B.hs, nothing )
+second run
+[2 of 3] Compiling B                ( B.hs, B.o )
+Linking Main ...
+15