Subzero: Build both Debug and Release version of llvm2ice.

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> LLVM_BIN_PATH=<path> \
 #        LIBCXX_INSTALL_PATH=<path> CLANG_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 19 matching lines @@
 
 HOST_ARCH ?= x86_64
 ifeq ($(HOST_ARCH),x86_64)
   HOST_FLAGS = -m64 -stdlib=libc++
 else
   ifeq ($(HOST_ARCH),x86)
     HOST_FLAGS = -m32 -stdlib=libc++
   endif
 endif
 
+ifdef DEBUG
+  OBJDIR = build/Debug
+  OPTLEVEL = -O0
+else
+  OBJDIR = build/Release
+  OPTLEVEL = -O2
+endif
+
 $(info -----------------------------------------------)
 $(info Using LLVM_SRC_PATH = $(LLVM_SRC_PATH))
 $(info Using LLVM_BIN_PATH = $(LLVM_BIN_PATH))
 $(info Using LIBCXX_INSTALL_PATH = $(LIBCXX_INSTALL_PATH))
 $(info Using CLANG_PATH = $(CLANG_PATH))
 $(info Using HOST_ARCH     = $(HOST_ARCH))
 $(info -----------------------------------------------)
 
 LLVM_CXXFLAGS := `$(LLVM_BIN_PATH)/llvm-config --cxxflags`
 LLVM_LDFLAGS := `$(LLVM_BIN_PATH)/llvm-config --libs` \
                 `$(LLVM_BIN_PATH)/llvm-config --ldflags`
 
 # It's recommended that CXX matches the compiler you used to build LLVM itself.
-OPTLEVEL := -O0
 CCACHE := `command -v ccache`
 CXX := CCACHE_CPP2=yes $(CCACHE) $(CLANG_PATH)/clang++
 
 CXXFLAGS := $(LLVM_CXXFLAGS) -std=c++11 -Wall -Wextra -Werror -fno-rtti \
         -fno-exceptions $(OPTLEVEL) -g $(HOST_FLAGS) \
         -Wno-error=unused-parameter -I$(LIBCXX_INSTALL_PATH)/include/c++/v1
 LDFLAGS := $(HOST_FLAGS) -L$(LIBCXX_INSTALL_PATH)/lib
 
 SRCS= \
         assembler.cpp \
@@ skipping 11 matching lines @@
         IceRegAlloc.cpp \
         IceRNG.cpp \
         IceTargetLowering.cpp \
         IceTargetLoweringX8632.cpp \
         IceTranslator.cpp \
         IceTypeConverter.cpp \
         IceTypes.cpp \
         llvm2ice.cpp \
         PNaClTranslator.cpp
 
-OBJS=$(patsubst %.cpp, build/%.o, $(SRCS))
+OBJS=$(patsubst %.cpp, $(OBJDIR)/%.o, $(SRCS))
 
 # Keep all the first target so it's the default.
-all: llvm2ice
+all: $(OBJDIR)/llvm2ice make_symlink
 
-.PHONY: all
+make_symlink: $(OBJDIR)/llvm2ice
+        rm -f llvm2ice
+        ln -s $(OBJDIR)/llvm2ice
 
-llvm2ice: $(OBJS)
+.PHONY: all make_symlink
+
+$(OBJDIR)/llvm2ice: $(OBJS)
         $(CXX) $(LDFLAGS) -o $@ $^ $(LLVM_LDFLAGS) -ldl \
                -Wl,-rpath=$(abspath $(LIBCXX_INSTALL_PATH)/lib)
 
 # TODO: Be more precise than "*.h" here and elsewhere.
-$(OBJS): build/%.o: src/%.cpp src/*.h src/*.def
+$(OBJS): $(OBJDIR)/%.o: src/%.cpp src/*.h src/*.def
         $(CXX) -c $(CXXFLAGS) $< -o $@
 
-$(OBJS): | build
+$(OBJS): | $(OBJDIR)
 
-build:
+$(OBJDIR):
         @mkdir -p $@
 
 check-lit: llvm2ice
         LLVM_BIN_PATH=$(LLVM_BIN_PATH) \
         $(LLVM_SRC_PATH)/utils/lit/lit.py -sv tests_lit
 
 check: check-lit
         (cd crosstest; ./runtests.sh)
 
 # TODO: Fix the use of wildcards.
@@ skipping 10 matching lines @@
   CLANG_FORMAT_DIFF = clang-format-diff.py
 else
   CLANG_FORMAT_DIFF = /usr/lib/clang-format/clang-format-diff.py
 endif
 format-diff:
         git diff -U0 `git merge-base HEAD master` | \
         $(CLANG_FORMAT_DIFF) -p1 -style=LLVM -i
 
 clean:
         rm -rf llvm2ice *.o build/