gcc: optionally build gccgo compiler

Tested with eglibc on x86 and armv7 so far

Signed-off-by: Matteo Croce <matteo.croce@canonical.com>

toolchain/gcc/Config.in

@@ -70,3 +70,11 @@ config INSTALL_GFORTRAN
 	default n
 	help
 	    Build/install GNU fortran compiler ?
+
+config INSTALL_GCCGO
+	bool
+	prompt "Build/install Go compiler?" if TOOLCHAINOPTS
+	depends on !GCC_VERSION_4_8 && (USE_GLIBC || BROKEN)
+	default n
+	help
+	    Build/install GNU gccgo compiler ?

toolchain/gcc/common.mk

@@ -69,12 +69,15 @@ HOST_STAMP_CONFIGURED:=$(GCC_BUILD_DIR)/.configured
 HOST_STAMP_INSTALLED:=$(STAGING_DIR_HOST)/stamp/.gcc_$(GCC_VARIANT)_installed
 
 SEP:=,
-TARGET_LANGUAGES:="c,c++$(if $(CONFIG_INSTALL_LIBGCJ),$(SEP)java)$(if $(CONFIG_INSTALL_GFORTRAN),$(SEP)fortran)"
+TARGET_LANGUAGES:="c,c++$(if $(CONFIG_INSTALL_LIBGCJ),$(SEP)java)$(if $(CONFIG_INSTALL_GFORTRAN),$(SEP)fortran)$(if $(CONFIG_INSTALL_GCCGO),$(SEP)go)"
 
 export libgcc_cv_fixed_point=no
 ifdef CONFIG_USE_UCLIBC
   export glibcxx_cv_c99_math_tr1=no
 endif
+ifdef CONFIG_INSTALL_GCCGO
+  export libgo_cv_c_split_stack_supported=no
+endif
 
 ifdef CONFIG_GCC_USE_GRAPHITE
   ifdef CONFIG_GCC_VERSION_4_8
@@ -164,12 +167,17 @@ ifneq ($(CONFIG_SOFT_FLOAT),y)
   endif
 endif
 
+ifeq ($(CONFIG_TARGET_x86)$(CONFIG_USE_GLIBC)$(CONFIG_INSTALL_GCCGO),yyy)
+  TARGET_CFLAGS+=-fno-split-stack
+endif
+
 GCC_MAKE:= \
 	export SHELL="$(BASH)"; \
 	$(MAKE) \
 		CFLAGS="$(HOST_CFLAGS)" \
 		CFLAGS_FOR_TARGET="$(TARGET_CFLAGS)" \
-		CXXFLAGS_FOR_TARGET="$(TARGET_CFLAGS)"
+		CXXFLAGS_FOR_TARGET="$(TARGET_CFLAGS)" \
+		GOCFLAGS_FOR_TARGET="$(TARGET_CFLAGS)"
 
 define Host/SetToolchainInfo
 	$(SED) 's,TARGET_CROSS=.*,TARGET_CROSS=$(REAL_GNU_TARGET_NAME)-,' $(TOOLCHAIN_DIR)/info.mk

toolchain/gcc/final/Makefile

@@ -39,7 +39,16 @@ define Host/Configure
 	);
 endef
 
+ifeq ($(CONFIG_USE_GLIBC)$(CONFIG_INSTALL_GCCGO),yy)
+define FixGogccCrt
+	# link crtX.o for gotools
+	mkdir -p $(GCC_BUILD_DIR)/gotools
+	$(foreach crt, i 1 n, ln -sf ../../glibc-dev/lib/crt$(crt).o $(GCC_BUILD_DIR)/gotools/ ; )
+endef
+endif
+
 define Host/Compile
+	$(FixGogccCrt)
 	+$(GCC_MAKE) $(HOST_JOBS) -C $(GCC_BUILD_DIR) all
 endef
 

toolchain/gcc/patches/5.4.0/960-go_libm.patch

@@ -0,0 +1,11 @@
+--- a/gcc/go/Make-lang.in
++++ b/gcc/go/Make-lang.in
+@@ -74,7 +74,7 @@ go_OBJS = $(GO_OBJS) go/gospec.o
+ 
+ go1$(exeext): $(GO_OBJS) attribs.o $(BACKEND) $(LIBDEPS)
+ 	+$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
+-	      $(GO_OBJS) attribs.o $(BACKEND) $(LIBS) $(BACKENDLIBS)
++	      $(GO_OBJS) attribs.o $(BACKEND) $(LIBS) $(BACKENDLIBS) -lm
+ 
+ # Documentation.
+ 

toolchain/gcc/patches/5.4.0/970-warn_bug.patch

@@ -0,0 +1,11 @@
+--- a/libgo/runtime/mprof.goc
++++ b/libgo/runtime/mprof.goc
+@@ -403,7 +403,7 @@ func ThreadCreateProfile(p Slice) (n int
+ 
+ func Stack(b Slice, all bool) (n int) {
+ 	byte *pc, *sp;
+-	bool enablegc;
++	bool enablegc = false; /* workaround GCC bug #36550 */
+ 	
+ 	sp = runtime_getcallersp(&b);
+ 	pc = (byte*)(uintptr)runtime_getcallerpc(&b);