optionally support parallel toolchain build. This defaults to off, because certain toolchain versions are known to break on parallel build. However, it significantly speeds up the build and latest versions of the tools do compile fine.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@23196 3c298f89-4303-0410-b956-a3cf2f4a3e73

Config.in

@@ -268,7 +268,7 @@ menu "Global build settings"
 
 	config PKG_DEFAULT_PARALLEL
 		bool
-		prompt "Always parallelize the default package build rule (Dangerous)"
+		prompt "Parallelize the default package build rule (May break build)"
 		depends on PKG_BUILD_PARALLEL
 		default n
 		help
@@ -278,7 +278,21 @@ menu "Global build settings"
 		  packages with multiple jobs that are probably not tested in
 		  a parallel build environment.
 
-		  Say N. Only say Y for testing.
+		  Only say Y, if you don't mind fixing broken packages.
+		  Before reporting build bugs, set this to N and re-run the build.
+
+	config TOOLCHAIN_PARALLEL
+		bool
+		prompt "Parallelize the toolchain build (May break build)"
+		depends on PKG_BUILD_PARALLEL
+		default n
+		help
+		  Build the toolchain with parallel make jobs.
+		  This speeds up the toolchain build on SMP machines, but may
+		  break the build for certain toolchain versions.
+
+		  If you say Y, toolchain build might break.
+		  Before reporting build bugs, set this to N and re-run the build.
 
 	comment "Stripping options"
 

include/toolchain-build.mk

@@ -11,6 +11,8 @@ REAL_STAGING_DIR_HOST:=$(STAGING_DIR_HOST)
 STAGING_DIR_HOST:=$(TOOLCHAIN_DIR)
 BUILD_DIR_HOST:=$(BUILD_DIR_TOOLCHAIN)
 
+TOOLCHAIN_JOBS?=$(if $(CONFIG_TOOLCHAIN_PARALLEL),-j$(CONFIG_PKG_BUILD_JOBS))
+
 include $(INCLUDE_DIR)/host-build.mk
 
 HOST_STAMP_PREPARED=$(HOST_BUILD_DIR)/.prepared

toolchain/binutils/Makefile

@@ -79,7 +79,7 @@ define Host/Configure
 endef
 
 define Host/Compile
-	$(MAKE) -C $(HOST_BUILD_DIR) all
+	$(MAKE) $(TOOLCHAIN_JOBS) -C $(HOST_BUILD_DIR) all
 endef
 
 define Host/Install

toolchain/gcc/common.mk

@@ -173,7 +173,7 @@ endif
 
 GCC_MAKE:= \
 	export SHELL="$(BASH)"; \
-	$(MAKE) \
+	$(MAKE) $(TOOLCHAIN_JOBS) \
 		CFLAGS_FOR_TARGET="$(TARGET_CFLAGS)" \
 		CXXFLAGS_FOR_TARGET="$(TARGET_CFLAGS)"
 

toolchain/uClibc/Makefile

@@ -109,7 +109,7 @@ UCLIBC_MAKE = PATH='$(TARGET_PATH)' $(MAKE) -C $(HOST_BUILD_DIR) \
 
 define Host/Compile
 	$(SED) 's,^CROSS=.*,CROSS=$(TARGET_CROSS),g' $(HOST_BUILD_DIR)/Rules.mak
-	$(UCLIBC_MAKE) PREFIX= all
+	$(UCLIBC_MAKE) $(TOOLCHAIN_JOBS) PREFIX= all
 	$(UCLIBC_MAKE) PREFIX="$(TOOLCHAIN_DIR)/" install_runtime install_dev
 	$(CP) $(HOST_BUILD_DIR)/libc/libc_so.a $(TOOLCHAIN_DIR)/lib/
 	$(CP) $(HOST_BUILD_DIR)/libpthread/*/libpthread_so.a $(TOOLCHAIN_DIR)/lib/