allow specific test for make check

Makefile.standalone

 # The following variables will likely need to be modified, depending on where
 # and how you built LLVM & Clang. They can be overridden in a command-line
 # invocation of make, like:
 #
 #   make LLVM_SRC_PATH=<path> LIBCXX_INSTALL_PATH=<path> CLANG_PATH=<path> \
 #        PNACL_BIN_PATH=<path> ...
 #
 
 # LLVM_SRC_PATH is the path to the root of the checked out source code. This
 # directory should contain the configure script, the include/ and lib/
@@ skipping 15 matching lines @@
 # tools like qemu.
 TOOLCHAIN_ROOT ?= $(shell readlink -e $(NACL_ROOT)/toolchain/linux_x86)
 
 # PNACL_TOOLCHAIN_ROOT is the location of the PNaCl toolchain.
 # This is used as the default root for finding binutils, libcxx, etc.
 PNACL_TOOLCHAIN_ROOT ?= $(shell readlink -e $(TOOLCHAIN_ROOT)/pnacl_newlib_raw)
 
 # The location of PNaCl tools (e.g., binutils objdump, pnacl-clang++, etc.).
 PNACL_BIN_PATH ?= $(shell readlink -e $(PNACL_TOOLCHAIN_ROOT)/bin)
 
+# Allow tests to be overridden, e.g.:
+#   make -f Makefile.standalone check-lit \
+#     CHECK_LIT_TESTS="tests_lit/llvm2ice_tests/{alloc,arith}.ll"
+#   make -f Makefile.standalone check-xtest \
+#     CHECK_XTEST_TESTS=crosstest/Output/simple_loop_x8632_native_O2_sse2.xtest
+CHECK_LIT_TESTS ?= tests_lit
+CHECK_XTEST_TESTS ?= crosstest/Output
+
 # Hack to auto-detect autoconf versus cmake build of LLVM.  If the LLVM tools
 # were dynamically linked with something like libLLVM-3.7svn.so, it is an
 # autoconf build, otherwise it is a cmake build.  AUTOCONF is set to 0 for
 # cmake, nonzero for autoconf.
 AUTOCONF ?= $(shell ldd $(PNACL_BIN_PATH)/opt | grep -c libLLVM-)
 
 # CLANG_PATH is the location of the clang compiler to use for building
 # the host binaries.
 CLANG_PATH ?= $(shell readlink -e \
   $(NACL_ROOT)/../third_party/llvm-build/Release+Asserts/bin)
@@ skipping 281 matching lines @@
 
 # Creates symbolic link so that testing is easier. Also runs
 # pnacl-sz to verify that the defines flags have valid values,
 # as well as describe the corresponding build attributes.
 make_symlink: $(OBJDIR)/pnacl-sz
         rm -rf pnacl-sz
         ln -s $(OBJDIR)/pnacl-sz
         @echo "Build Attributes:"
         @$(SHOW_BUILD_ATTS)
 
-.PHONY: all compile_only make_symlink runtime bloat sb docs
+.PHONY: all compile_only make_symlink runtime bloat sb docs help \
+help-check-lit help-check-xtest
 
 compile_only: $(OBJS)
 
 $(OBJDIR)/pnacl-sz: $(OBJS)
         $(CXX) $(LDFLAGS) -o $@ $^ $(LLVM_LDFLAGS) \
           -Wl,-rpath=$(abspath $(LIBCXX_INSTALL_PATH)/lib)
 
 $(SB_OBJDIR)/pnacl-sz.x86-32.nexe: $(SB_OBJS)
         $(eval PNACL_SZ_BASE := $(patsubst %.nexe, %, $@))
         $(SB_CXX) $(SB_LDFLAGS) -o $(PNACL_SZ_BASE).nonfinal.pexe $^ \
@@ skipping 60 matching lines @@
 # Use runtime.is.built so that build-runtime.py is invoked only once
 # even in a parallel build.
 .INTERMEDIATE: runtime.is.built
 $(RT_OBJ): runtime.is.built
 runtime.is.built: $(RT_SRC) pydir/build-runtime.py
         @echo ================ Building Subzero runtime ================
         ./pydir/build-runtime.py -v --pnacl-root $(PNACL_TOOLCHAIN_ROOT)
 
 check-lit: $(OBJDIR)/pnacl-sz make_symlink
         PNACL_BIN_PATH=$(PNACL_BIN_PATH) \
-        $(LLVM_SRC_PATH)/utils/lit/lit.py -sv tests_lit \
+        $(LLVM_SRC_PATH)/utils/lit/lit.py -sv $(CHECK_LIT_TESTS) \
             $(FORCEASM_LIT_TEST_EXCLUDES) $(FORCEASM_LIT_PARAM)
 
 ifdef MINIMAL
 check-xtest: $(OBJDIR)/pnacl-sz make_symlink runtime
         @echo "Crosstests disabled, minimal build"
 else
 check-xtest: $(OBJDIR)/pnacl-sz make_symlink runtime
        # Do all native/sse2 tests, but only test_vector_ops for native/sse4.1.
        # For (slow) sandboxed tests, limit to Om1/sse4.1.
         ./pydir/crosstest_generator.py -v --lit \
           --toolchain-root $(TOOLCHAIN_ROOT) \
           $(FORCEASM_FLAG) \
           $(FORCEASM_XTEST_EXCLUDES) \
           -i x8632,native,sse2 \
           -i x8632,native,sse4.1,test_vector_ops \
           -i x8632,sandbox,sse4.1,Om1 \
           -i x8632,nonsfi,sse2,O2 \
           -i x8664,native,sse2 \
           -i x8664,native,sse4.1,test_vector_ops \
           -i x8664,sandbox,sse4.1,Om1 \
           -i arm32,neon \
           -e arm32,nonsfi \
           -e arm32,neon,test_vector_ops \
           -e arm32,neon,test_select
         PNACL_BIN_PATH=$(PNACL_BIN_PATH) \
-        $(LLVM_SRC_PATH)/utils/lit/lit.py -sv crosstest/Output
+        $(LLVM_SRC_PATH)/utils/lit/lit.py -sv $(CHECK_XTEST_TESTS)
 endif
 
 check-unit: $(OBJDIR)/run_unittests
         $(OBJDIR)/run_unittests
 
 # List the spec2k components in roughly reverse order of runtime, to help with
 # parallel execution speed.
 ALLSPEC := 253.perlbmk 177.mesa 188.ammp 256.bzip2 164.gzip 179.art 183.equake \
            175.vpr 176.gcc 181.mcf 186.crafty 197.parser 254.gap 255.vortex \
            300.twolf 252.eon
@@ skipping 90 matching lines @@
           -p1 -style=LLVM -i
 
 bloat: make_symlink
         nm -C -S -l pnacl-sz | \
           bloat/bloat.py --nm-output=/dev/stdin syms > build/pnacl-sz.bloat.json
         @echo See Subzero size breakdown in bloat/pnacl-sz.bloat.html
 
 docs:
         make -C docs -f Makefile.standalone
 
+help:
+        @cat Makefile.standalone-help/help.txt
+
+help-check-lit:
+        @cat Makefile.standalone-help/check-lit.txt
+
+help-check-xtest:
+        @cat Makefile.standalone-help/check-xtest.txt
+
 clean:
         rm -rf pnacl-sz *.o $(OBJDIR) $(SB_OBJDIR) build/pnacl-sz.bloat.json
 
 clean-all: clean
         rm -rf build/  crosstest/Output/