Update makefiles to allow LTO builds

Fraser Gordon · Fraser Gordon · commit c598a33873f0 · 2014-08-22T16:54:41.000+01:00
diff --git a/engine/Makefile.common b/engine/Makefile.common
@@ -24,7 +24,8 @@ CUSTOM_CCFLAGS=\
 	-fmessage-length=0 \
 	$(MODE_CCFLAGS)
 
-CUSTOM_LDFLAGS=-static-libgcc \
-	$(MODE_LDFLAGS) -Wl,-rpath,\$$ORIGIN
+CUSTOM_LDFLAGS=$(MODE_LDFLAGS)
+CUSTOM_LDFLAGS_LTO=$(MODE_LDFLAGS_LTO) -static-libgcc -Wl,-rpath,\$$ORIGIN
+CUSTOM_LDFLAGS_FINAL=$(MODE_LDFLAGS_FINAL) -rpath \$$ORIGIN
 
 include $(dir $(lastword $(MAKEFILE_LIST)))/../rules/application.linux.makefile
diff --git a/engine/Makefile.installer b/engine/Makefile.installer
@@ -9,7 +9,6 @@ MODE_SOURCES= \
 MODE_DEFINES=\
 	MODE_INSTALLER
 
-MODE_LDFLAGS=\
-	-Wl,--script=installer-$(ARCH).link
+MODE_LDFLAGS_FINAL=--script=installer-$(ARCH).link
 
 include Makefile.common
diff --git a/engine/Makefile.standalone b/engine/Makefile.standalone
@@ -10,7 +10,6 @@ MODE_DEPS=libkernel-standalone.a
 
 MODE_LIBS=kernel-standalone
 
-MODE_LDFLAGS=\
-	-Wl,--script=standalone-$(ARCH).link
+MODE_LDFLAGS_FINAL=--script=standalone-$(ARCH).link
 
 include Makefile.common
diff --git a/rules/application.linux.makefile b/rules/application.linux.makefile
@@ -26,13 +26,17 @@ else
 	STATIC_LIBS+=stdc++
 endif
 
-LDFLAGS=$(CUSTOM_LDFLAGS) $(addprefix -L,$(GLOBAL_LIBS)) $(addprefix -L,$(CUSTOM_INCLUDES)) -Xlinker -no-undefined $(addprefix -Xlinker --exclude-libs -Xlinker ,$(addsuffix .a,$(addprefix lib,$(STATIC_LIBS))))
+LDFLAGS_COMMON=$(addprefix -L,$(GLOBAL_LIBS)) $(addprefix -L,$(CUSTOM_INCLUDES))
+LDFLAGS_LTO:=$(CUSTOM_LDFLAGS_LTO) $(CUSTOM_LDFLAGS) $(LDFLAGS_COMMON) -Xlinker -no-undefined $(addprefix -Xlinker --exclude-libs -Xlinker ,$(addsuffix .a,$(addprefix lib,$(STATIC_LIBS))))
+LDFLAGS_FINAL:=$(CUSTOM_LDFLAGS_FINAL) $(CUSTOM_LDFLAGS) $(LDFLAGS_COMMON) -no-undefined $(addprefix --exclude-libs ,$(addsuffix .a,$(addprefix lib,$(STATIC_LIBS))))
 
 TARGET_PATH=$(BUILD_DIR)/$(NAME)
 
-$(TARGET_PATH): $(OBJECTS) $(DEPS)
-	mkdir -p $(dir $(TARGET_PATH))
-	$(CC) -fvisibility=hidden -o$(TARGET_PATH) $(LDFLAGS) $(OBJECTS) $(CUSTOM_OBJECTS) \
+ifeq ($(LD_IS_CC),1)
+	# If we are using the compiler to link, we need to prefix the linker options
+	LDFLAGS_FINAL:=$(addprefix -Xlinker ,$(LDFLAGS_FINAL))
+
+	LINK_STEP1:=$(CC) -fvisibility=hidden -o$(TARGET_PATH) $(LDFLAGS_LTO) $(LDFLAGS_FINAL) $(OBJECTS) $(CUSTOM_OBJECTS) \
 			-Wl,-Bstatic \
 			-Wl,--start-group \
 				$(addsuffix .a,$(addprefix $(PRODUCT_DIR)/lib,$(LIBS))) \
@@ -41,6 +45,26 @@ $(TARGET_PATH): $(OBJECTS) $(DEPS)
 			-Wl,-Bdynamic \
 			$(addsuffix .so,$(addprefix $(PRODUCT_DIR)/,$(SHARED_LIBS))) \
 			$(addprefix -l,$(DYNAMIC_LIBS))
+	LINK_STEP2:=
+else
+	LINK_STEP1:=$(CC) -Wl,-relocatable -fvisibility=hidden -o$(TARGET_PATH).rel $(LDFLAGS_LTO) $(OBJECTS) $(CUSTOM_OBJECTS) \
+			-Wl,-Bstatic \
+			-Wl,--start-group \
+				$(addsuffix .a,$(addprefix $(PRODUCT_DIR)/lib,$(LIBS))) \
+				$(addprefix -l,$(STATIC_LIBS)) \
+			-Wl,--end-group
+	LINK_STEP2:=$(LD) -o$(TARGET_PATH) $(LDFLAGS_FINAL) $(TARGET_PATH).rel \
+			-Bdynamic \
+			$(addsuffix .so,$(addprefix $(PRODUCT_DIR)/,$(SHARED_LIBS))) \
+			$(addprefix -l,$(DYNAMIC_LIBS))
+endif
+
+
+$(TARGET_PATH): $(OBJECTS) $(DEPS)
+	mkdir -p $(dir $(TARGET_PATH))
+	$(LINK_STEP1)
+	$(LINK_STEP2)
+
 ifneq ($(MODE),debug)
 	cd $(BUILD_DIR) && \
 		$(OBJCOPY) --only-keep-debug "$(NAME)" "$(NAME).dbg" && \
diff --git a/rules/environment.linux.makefile b/rules/environment.linux.makefile
@@ -25,6 +25,11 @@ ifeq ($(CC),)
 	CC:=gcc
 endif
 
+ifeq ($(origin LD), default)
+	LD:=$(CC)
+	LD_IS_CC:=1
+endif
+
 BUILD_DIR=$(SOLUTION_DIR)/_build/linux/$(ARCH)/$(MODE)
 CACHE_DIR=$(SOLUTION_DIR)/_cache/linux/$(ARCH)/$(MODE)/$(NAME)
 PRODUCT_DIR=$(BUILD_DIR)
