Build llvm fe in make test, enable parallel build

Summary:public
All frontends and the backend should be built by `make test`
irrespective of configure flags.

This diff also re-enables parallel building for the compilation of
infer done by the `test` target.  The ocaml unit tests, tracebugs
tests, and everything run by buck are still sequential.  Enabling
parallel builds roughly halves the time spent building infer.

This diff computes the number of cpus (NCPU) at configure time.

Reviewed By: jvillard

Differential Revision: D3121658

fb-gh-sync-id: a667cf8
fbshipit-source-id: a667cf8

Makefile.in

@@ -29,6 +29,8 @@ TARGETS_TO_TEST += objc
 endif
 TARGETS_TO_TEST := $(shell echo $(TARGETS_TO_TEST))
 
+NCPU = @NCPU@
+
 all: $(INFER_ANALYZERS)
 
 java: inferTraceBugs
@@ -86,21 +88,28 @@ endif
 clang: clang_plugin
 endif
 
+test_build_clang: clang_plugin
+	$(MAKE) -C $(INFER_DIR) clang
+
+test_build_java:
+	$(MAKE) -C $(INFER_DIR) java
+
+test_build_llvm:
+	$(MAKE) -C $(INFER_DIR) llvm
+
+test_build: test_build_clang test_build_java test_build_llvm
+
 unit:
 	$(MAKE) -C $(SRC_DIR) unit
 
-test_build:
-	$(MAKE) -C $(SRC_DIR) test_clean
-	$(MAKE) -C $(SRC_DIR) test_build
-
 ifeq (@BUILD_C_ANALYZERS@,yes)
 test_build: clang_plugin
 endif
 
-ocaml_unit_test: $(INFER_ANALYZERS) unit
+ocaml_unit_test: test_build unit
 	$(INFERUNIT_BIN)
 
-buck_test: $(INFER_ANALYZERS)
+buck_test: test_build
 	NO_BUCKD=1 buck clean
 	NO_BUCKD=1 buck test $(TARGETS_TO_TEST)
 ifeq (@BUILD_JAVA_ANALYZERS@,yes)
@@ -115,9 +124,9 @@ ifeq (@BUILD_JAVA_ANALYZERS@,yes)
 endif
 
 inferTraceBugs:
-	make -C infer $(INFERTRACEBUGS_BIN)
+	$(MAKE) -C $(INFER_DIR) $(INFERTRACEBUGS_BIN)
 
-inferTraceBugs_test: $(INFER_ANALYZERS)
+inferTraceBugs_test: test_build
 ifeq (@BUILD_JAVA_ANALYZERS@,yes)
 	$(INFER_BIN) -o __test-infer-out__ -- \
 	  javac $(EXAMPLES_DIR)/Hello.java \
@@ -139,7 +148,11 @@ endif
 	  --only-show > /dev/null
 	@rm -fr __test-infer-out__
 
-test: ocaml_unit_test buck_test inferTraceBugs_test
+test:
+	$(MAKE) -C $(INFER_DIR) $(INFER_BIN)
+	$(MAKE) -C $(SRC_DIR) init
+	$(MAKE) -j$(NCPU) test_build
+	$(MAKE) ocaml_unit_test buck_test inferTraceBugs_test
 
 test_xml: buck_test_xml
 

configure.ac

@@ -240,6 +240,26 @@ echo $buck_version > "$buckversion_file"
 AC_MSG_RESULT([$buck_version])
 
 
+AC_CHECK_TOOL([HAVE_NPROC], [nproc], [no])
+AC_CHECK_TOOL([HAVE_SYSCTL], [sysctl], [no])
+AC_MSG_CHECKING([the number of cpus the build host has])
+if test "$HAVE_NPROC" != "no"; then
+  if test $(nproc); then
+    NCPU=$(nproc)
+    AC_MSG_RESULT([$NCPU])
+  fi
+elif test $"HAVE_SYSCTL" != "no"; then
+  if test $(sysctl -n hw.ncpu); then
+    NCPU=$(sysctl -n hw.ncpu)
+    AC_MSG_RESULT([$NCPU])
+  fi
+else
+  NCPU=1
+  AC_MSG_RESULT([failed, defaulting to 1])
+fi
+AC_SUBST([NCPU])
+
+
 AC_CONFIG_FILES([
   Makefile.config
   Makefile