BaseTools: Allow users to specify compiler to use with make CC= CXX=

In https://bugzilla.tianocore.org/show_bug.cgi?id=2842 clang support was
added by having users specify "make CXX=llvm" when building BaseTools.

The Makefile then sees that and sets CC=$(CLANG_BIN)clang and
CXX=$(CLANG_BIN)clang++. That requires that the executables 'clang' and
'clang++' exist and for example aren't named 'clang-17' and
'clang++-17'. Also, it's an unusual way of specifying the compiler,
since many users will expect to be able to override CC and CXX on the
make command line.

Rework the BaseTools Makefiles removing the 'BUILD_' prefix (BUILD_CC
and BUILD_CXX) and using the standard name 'LDFLAGS' instead of
'LFLAGS'. This allows clang to be used by running
'make -C BaseTools CC=clang CXX=clang++'.

Signed-off-by: Rebecca Cran <rebecca@quicinc.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>

BaseTools/Source/C/Makefiles/app.makefile

@@ -15,7 +15,7 @@ APPLICATION = $(MAKEROOT)/bin/$(APPNAME)
 all: $(MAKEROOT)/bin $(APPLICATION)
 
 $(APPLICATION): $(OBJECTS)
-	$(LINKER) -o $(APPLICATION) $(BUILD_LFLAGS) $(OBJECTS) -L$(MAKEROOT)/libs $(LIBS)
+	$(LINKER) -o $(APPLICATION) $(LDFLAGS) $(OBJECTS) -L$(MAKEROOT)/libs $(LIBS)
 
 $(OBJECTS): $(MAKEROOT)/Include/Common/BuildVersion.h
 

BaseTools/Source/C/Makefiles/footer.makefile

@@ -15,13 +15,13 @@ install: $(MAKEROOT)/libs-$(HOST_ARCH) $(LIBRARY)
 	cp $(LIBRARY) $(MAKEROOT)/libs-$(HOST_ARCH)
 
 $(LIBRARY): $(OBJECTS)
-	$(BUILD_AR) crs $@ $^
+	$(AR) crs $@ $^
 
 %.o : %.c
-	$(BUILD_CC)  -c $(BUILD_CPPFLAGS) $(BUILD_CFLAGS) $< -o $@
+	$(CC)  -c $(CPPFLAGS) $(CFLAGS) $< -o $@
 
 %.o : %.cpp
-	$(BUILD_CXX) -c $(BUILD_CPPFLAGS) $(BUILD_CXXFLAGS) $< -o $@
+	$(CXX) -c $(CPPFLAGS) $(CXXFLAGS) $< -o $@
 
 .PHONY: clean
 clean:

BaseTools/Source/C/Makefiles/header.makefile

@@ -45,19 +45,19 @@ CYGWIN:=$(findstring CYGWIN, $(shell uname -s))
 LINUX:=$(findstring Linux, $(shell uname -s))
 DARWIN:=$(findstring Darwin, $(shell uname -s))
 ifeq ($(CXX), llvm)
-BUILD_CC ?= $(CLANG_BIN)clang
-BUILD_CXX ?= $(CLANG_BIN)clang++
-BUILD_AS ?= $(CLANG_BIN)clang
-BUILD_AR ?= $(CLANG_BIN)llvm-ar
-BUILD_LD ?= $(CLANG_BIN)llvm-ld
+CC ?= $(CLANG_BIN)clang
+CXX ?= $(CLANG_BIN)clang++
+AS ?= $(CLANG_BIN)clang
+AR ?= $(CLANG_BIN)llvm-ar
+LD ?= $(CLANG_BIN)llvm-ld
 else
-BUILD_CC ?= gcc
-BUILD_CXX ?= g++
-BUILD_AS ?= gcc
-BUILD_AR ?= ar
-BUILD_LD ?= ld
+CC ?= gcc
+CXX ?= g++
+AS ?= gcc
+AR ?= ar
+LD ?= ld
 endif
-LINKER ?= $(BUILD_CC)
+LINKER ?= $(CC)
 ifeq ($(HOST_ARCH), IA32)
 ARCH_INCLUDE = -I $(MAKEROOT)/Include/Ia32/
 
@@ -81,34 +81,34 @@ $(error Bad HOST_ARCH)
 endif
 
 INCLUDE = $(TOOL_INCLUDE) -I $(MAKEROOT) -I $(MAKEROOT)/Include/Common -I $(MAKEROOT)/Include/ -I $(MAKEROOT)/Include/IndustryStandard -I $(MAKEROOT)/Common/ -I .. -I . $(ARCH_INCLUDE)
-BUILD_CPPFLAGS = $(INCLUDE)
+CPPFLAGS = $(INCLUDE)
 
 # keep EXTRA_OPTFLAGS last
 BUILD_OPTFLAGS = -O2 $(EXTRA_OPTFLAGS)
 
 ifeq ($(DARWIN),Darwin)
 # assume clang or clang compatible flags on OS X
-BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror \
+CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -Wall -Werror \
 -Wno-deprecated-declarations -Wno-self-assign -Wno-unused-result -nostdlib -g
 else
 ifeq ($(CXX), llvm)
-BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -fwrapv \
+CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -fwrapv \
 -fno-delete-null-pointer-checks -Wall -Werror \
 -Wno-deprecated-declarations -Wno-self-assign \
 -Wno-unused-result -nostdlib -g
 else
-BUILD_CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -fwrapv \
+CFLAGS = -MD -fshort-wchar -fno-strict-aliasing -fwrapv \
 -fno-delete-null-pointer-checks -Wall -Werror \
 -Wno-deprecated-declarations -Wno-stringop-truncation -Wno-restrict \
 -Wno-unused-result -nostdlib -g
 endif
 endif
 ifeq ($(CXX), llvm)
-BUILD_LFLAGS =
-BUILD_CXXFLAGS = -Wno-deprecated-register -Wno-unused-result
+LDFLAGS =
+CXXFLAGS = -Wno-deprecated-register -Wno-unused-result
 else
-BUILD_LFLAGS =
-BUILD_CXXFLAGS = -Wno-unused-result
+LDFLAGS =
+CXXFLAGS = -Wno-unused-result
 endif
 ifeq ($(HOST_ARCH), IA32)
 #
@@ -117,18 +117,18 @@ ifeq ($(HOST_ARCH), IA32)
 #  so only do this is uname -m returns i386.
 #
 ifeq ($(DARWIN),Darwin)
-  BUILD_CFLAGS   += -arch i386
-  BUILD_CPPFLAGS += -arch i386
-  BUILD_LFLAGS   += -arch i386
+  CFLAGS   += -arch i386
+  CPPFLAGS += -arch i386
+  LDFLAGS  += -arch i386
 endif
 endif
 
 # keep BUILD_OPTFLAGS last
-BUILD_CFLAGS   += $(BUILD_OPTFLAGS)
-BUILD_CXXFLAGS += $(BUILD_OPTFLAGS)
+CFLAGS   += $(BUILD_OPTFLAGS)
+CXXFLAGS += $(BUILD_OPTFLAGS)
 
 # keep EXTRA_LDFLAGS last
-BUILD_LFLAGS += $(EXTRA_LDFLAGS)
+LDFLAGS += $(EXTRA_LDFLAGS)
 
 .PHONY: all
 .PHONY: install