Build clang libraries by default with -fno-exceptions and with

-fno-rtti. The clang libaries that really use exceptions and virtual
functions can enable LLVM_REQUIRES_EH and LLVM_REQUIRES_RTTI
respectively. This saves space on the resulting binaries and follows
what's being done upstream.

Submitted by:	Dimitry Andric <dimitry at andric.com>

lib/clang/clang.build.mk

@@ -17,6 +17,17 @@ TARGET_ARCH?=	${MACHINE_ARCH}
 # XXX: 8.0, to keep __FreeBSD_cc_version happy
 CFLAGS+=-DLLVM_HOSTTRIPLE=\"${TARGET_ARCH}-undermydesk-freebsd9.0\"
 
+.ifndef LLVM_REQUIRES_EH
+CFLAGS+=-fno-exceptions
+.else
+# If the library or program requires EH, it also requires RTTI.
+LLVM_REQUIRES_RTTI=
+.endif
+
+.ifndef LLVM_REQUIRES_RTTI
+CFLAGS+=-fno-rtti
+.endif
+
 .PATH:	${LLVM_SRCS}/${SRCDIR}
 
 TBLGEN=tblgen ${CFLAGS:M-I*}

lib/clang/libllvmcore/Makefile

@@ -35,6 +35,7 @@ SRCS=	AsmWriter.cpp \
 	ValueSymbolTable.cpp \
 	ValueTypes.cpp \
 	Verifier.cpp
+LLVM_REQUIRES_RTTI=
 
 TGHDRS=	Intrinsics
 

lib/clang/libllvmsupport/Makefile

@@ -48,5 +48,6 @@ SRCS=	APFloat.cpp \
 	regexec.c \
 	regfree.c \
 	regstrlcpy.c
+LLVM_REQUIRES_RTTI=
 
 .include "../clang.lib.mk"

lib/clang/libllvmsystem/Makefile

@@ -22,5 +22,6 @@ SRCS=	Alarm.cpp \
 	Threading.cpp \
 	TimeValue.cpp \
 	Valgrind.cpp
+LLVM_REQUIRES_RTTI=
 
 .include "../clang.lib.mk"

usr.bin/clang/tblgen/Makefile

@@ -40,6 +40,7 @@ SRCS=	ARMDecoderEmitter.cpp \
 	X86DisassemblerTables.cpp \
 	X86RecognizableInstr.cpp
 MAN=
+LLVM_REQUIRES_EH=
 
 LIBDEPS=llvmsupport llvmsystem