Avoid shell call for autogenerated-EXTRA_CFLAGS.txt

Instead of passing the contents of autogenerated-EXTRA_CFLAGS.txt on the
gcc command line, read it in and use it to decide whether to run gcc or
g++.  This also produces a cleaner failure mode if
autogenerated-EXTRA_CFLAGS.txt has an unexpected value.

Author: Kevin Pyle

Makefile

@@ -116,8 +116,10 @@ CPPFLAGS+= -I$(GCCPLUGINS_DIR)/include -I$(GCCPLUGINS_DIR)/include/c-family -I.
 # Allow user to pick optimization, choose whether warnings are fatal,
 # and choose debugging information level.
 CFLAGS?=-O2 -Werror -g
+CXXFLAGS?=-O2 -Werror -g
 # Force these settings
 CFLAGS+= -fPIC -fno-strict-aliasing -Wall
+CXXFLAGS+= -fPIC -fno-strict-aliasing -Wall
 LIBS+= $(PYTHON_LIBS)
 ifneq "$(PLUGIN_PYTHONPATH)" ""
   CPPFLAGS+= -DPLUGIN_PYTHONPATH='"$(PLUGIN_PYTHONPATH)"'
@@ -136,23 +138,39 @@ plugin: autogenerated-config.h $(PLUGIN_DSO)
 #
 INVOCATION_ENV_VARS := LD_LIBRARY_PATH=gcc-c-api CC="$(TARGET_GCC)"
 
+, := ,
+
+define run-cc
+	set -- $1; \
+	read gcc_cxx < "autogenerated-EXTRA_CFLAGS.txt";	\
+	if [ "$$gcc_cxx" = '-x c' ]; then	\
+		$(if $2,$2,$(CC) $(CFLAGS)) "$$@";	\
+	elif [ "$$gcc_cxx" = '-x c++' ]; then	\
+		$(if $3,$3,$(CXX) $(CXXFLAGS)) "$$@";	\
+	else	\
+		false;	\
+	fi
+endef
+
 # When installing, both the plugin and libgcc-c-api.so will be installed to
 # $(GCCPLUGINS_DIR), so we give the plugin an RPATH of $(GCCPLUGINS_DIR)
 # so that it finds the libgcc-c-api.so there (to support the case of having
 # multiple GCCs installed)
 #
 $(PLUGIN_DSO): $(PLUGIN_OBJECT_FILES) $(LIBGCC_C_API_SO)
-	$(CC) \
-	    $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) \
+	$(call run-cc, \
 	    -shared \
 	    $(PLUGIN_OBJECT_FILES) \
-	    -o $@ \
 	    $(LIBS) \
-	    -lgcc-c-api -Lgcc-c-api -Wl,-rpath=$(GCCPLUGINS_DIR)
+		$(OUTPUT_OPTION) \
+	    -lgcc-c-api -Lgcc-c-api -Wl$(,)-rpath=$(GCCPLUGINS_DIR), \
+		$(LINK.c), \
+		$(LINK.cpp) \
+	)
 
 .PHONY: gcc-c-api/phony-stamp-gcc-api
 gcc-c-api/phony-stamp-gcc-api: autogenerated-EXTRA_CFLAGS.txt
-	$(MAKE) -C gcc-c-api libgcc-c-api.so CC="$(CC)" TARGET_GCC="$(TARGET_GCC)"
+	$(MAKE) -C gcc-c-api libgcc-c-api.so CC="$(CC)" CXX="$(CXX)" TARGET_GCC="$(TARGET_GCC)"
 
 $(LIBGCC_C_API_SO): gcc-c-api/phony-stamp-gcc-api
 
@@ -161,7 +179,7 @@ $(PLUGIN_OBJECT_GENERATED_FILES): CPPFLAGS+= $(if $(srcdir),-I$(srcdir))
 # This is the standard .c->.o recipe, but it needs to be stated
 # explicitly to support the case that $(srcdir) is not blank.
 $(PLUGIN_OBJECT_SOURCE_FILES) $(PLUGIN_OBJECT_GENERATED_FILES): %.o: $(srcdir)%.c autogenerated-config.h $(srcdir)gcc-python.h $(LIBGCC_C_API_SO) autogenerated-EXTRA_CFLAGS.txt
-	$(COMPILE.c) $(shell cat autogenerated-EXTRA_CFLAGS.txt) $(OUTPUT_OPTION) $<
+	$(call run-cc,$< $(OUTPUT_OPTION),$(COMPILE.c),$(COMPILE.cpp))
 
 # Use a long variable name to avoid unwanted matches.  Add an explicit
 # -x c since gcc requires a language specifier when processing stdin.

gcc-c-api/Makefile

@@ -80,18 +80,32 @@ CPPFLAGS+= -I$(GCCPLUGINS_DIR)/include -I$(GCCPLUGINS_DIR)/include/c-family -I.
 # Allow user to pick optimization, choose whether warnings are fatal,
 # and choose debugging information level.
 CFLAGS?=-O2 -Werror -g
+CXXFLAGS?=-O2 -Werror -g
 # Force these settings
 CFLAGS+= -fPIC -fno-strict-aliasing -Wall
+CXXFLAGS+= -fPIC -fno-strict-aliasing -Wall
+
+define run-cc
+	set -- $1; \
+	read gcc_cxx < "../autogenerated-EXTRA_CFLAGS.txt";	\
+	if [ "$$gcc_cxx" = '-x c' ]; then	\
+		$(if $2,$2,$(CC) $(CFLAGS)) "$$@";	\
+	elif [ "$$gcc_cxx" = '-x c++' ]; then	\
+		$(if $3,$3,$(CXX) $(CXXFLAGS)) "$$@";	\
+	else	\
+		false;	\
+	fi
+endef
 
 all: $(LIBGCC_C_API_SO)
 
 $(LIBGCC_C_API_SO): $(OBJECT_FILES)
-	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -shared $^ -o $@ $(LIBS)
+	$(call run-cc,-shared $^ $(OUTPUT_OPTION) $(LIBS),$(LINK.c),$(LINK.cpp))
 
 # This is the standard .c->.o recipe, but it needs to be stated
 # explicitly to support the case that $(srcdir) is not blank.
 $(OBJECT_FILES): %.o: $(srcdir)%.c $(GENERATED_HEADERS) ../autogenerated-EXTRA_CFLAGS.txt
-	$(COMPILE.c) $(shell cat ../autogenerated-EXTRA_CFLAGS.txt) $(OUTPUT_OPTION) $<
+	$(call run-cc,$< $(OUTPUT_OPTION),$(COMPILE.c),$(COMPILE.cpp))
 
 autogenerated-casts.c: $(SOURCE_XML) xmltypes.py generate-casts-c.py
 	$(PYTHON) generate-casts-c.py $@

generate-config-h.py

@@ -89,6 +89,7 @@ def with_cplusplus():
                 self.extra_compilation_args += ['-x', 'c++']
             def with_c():
                 check.okmsg = 'C'
+                self.extra_compilation_args += ['-x', 'c']
             auto_host_h = os.path.join(self.plugindir, 'include', 'auto-host.h')
             with open(auto_host_h, 'r') as f:
                 content = f.read()