feat: make compatible with openperf

Makefile

@@ -2,7 +2,8 @@
 
 ### *Get a more readable version of this Makefile* by `make html` (requires python-markdown)
 html:
-	cat Makefile | sed 's/^\([^#]\)/    \1/g' | markdown_py > Makefile.html
+	# cat Makefile | sed 's/^\([^#]\)/    \1/g' | markdown_py > Makefile.html
+	cat Makefile | markdown_py > Makefile.html
 .PHONY: html
 
 ## 1. Basic Setup and Checks
@@ -66,21 +67,21 @@ LINKAGE   = $(OBJS) \
 ## 3. General Compilation Flags
 
 ### (Cross) compilers, e.g., mips-linux-gnu-g++
-AS        = $(CROSS_COMPILE)gcc
-CC        = $(CROSS_COMPILE)gcc
-CXX       = $(CROSS_COMPILE)g++
-LD        = $(CROSS_COMPILE)ld
-AR        = $(CROSS_COMPILE)ar
-OBJDUMP   = $(CROSS_COMPILE)objdump
-OBJCOPY   = $(CROSS_COMPILE)objcopy
-READELF   = $(CROSS_COMPILE)readelf
+CC        ?= $(CROSS_COMPILE)gcc
+AS        := $(CC)
+CXX       ?= $(CROSS_COMPILE)g++
+LD        ?= $(CROSS_COMPILE)ld
+AR        ?= $(CROSS_COMPILE)ar
+OBJDUMP   ?= $(CROSS_COMPILE)objdump
+OBJCOPY   ?= $(CROSS_COMPILE)objcopy
+READELF   ?= $(CROSS_COMPILE)readelf
 
 ### Compilation flags
 INC_PATH += $(WORK_DIR)/include $(addsuffix /include/, $(addprefix $(AM_HOME)/, $(LIBS)))
 INCFLAGS += $(addprefix -I, $(INC_PATH))
 
 ARCH_H := arch/$(ARCH).h
-CFLAGS   += -O2 -MMD -Wall -Werror $(INCFLAGS) \
+CFLAGS   += -lm -g -O3 -MMD -Wall $(INCFLAGS) \
             -D__ISA__=\"$(ISA)\" -D__ISA_$(shell echo $(ISA) | tr a-z A-Z)__ \
             -D__ARCH__=$(ARCH) -D__ARCH_$(shell echo $(ARCH) | tr a-z A-Z | tr - _) \
             -D__PLATFORM__=$(PLATFORM) -D__PLATFORM_$(shell echo $(PLATFORM) | tr a-z A-Z | tr - _) \
@@ -88,14 +89,20 @@ CFLAGS   += -O2 -MMD -Wall -Werror $(INCFLAGS) \
             -fno-asynchronous-unwind-tables -fno-builtin -fno-stack-protector \
             -Wno-main -U_FORTIFY_SOURCE -fvisibility=hidden
 CXXFLAGS +=  $(CFLAGS) -ffreestanding -fno-rtti -fno-exceptions
-ASFLAGS  += -MMD $(INCFLAGS)
-LDFLAGS  += -z noexecstack $(addprefix -T, $(LDSCRIPTS))
+ASFLAGS  += $(INCFLAGS)
+LDFLAGS  += -z noexecstack
 
 ## 4. Arch-Specific Configurations
 
 ### Paste in arch-specific configurations (e.g., from `scripts/x86_64-qemu.mk`)
 -include $(AM_HOME)/scripts/$(ARCH).mk
 
+### Fall back to native gcc/binutils if there is no cross compiler
+ifeq ($(wildcard $(shell which $(CC))),)
+  $(info #  $(CC) not found; fall back to default gcc and binutils)
+  CROSS_COMPILE := riscv64-unknown-linux-gnu-
+endif
+
 ## 5. Compilation Rules
 
 ### Rule (compile): a single `.c` -> `.o` (gcc)
@@ -123,19 +130,14 @@ $(LIBS): %:
 	@$(MAKE) -s -C $(AM_HOME)/$* archive
 
 ### Rule (link): objects (`*.o`) and libraries (`*.a`) -> `IMAGE.elf`, the final ELF binary to be packed into image (ld)
-$(IMAGE).elf: $(LINKAGE) $(LDSCRIPTS)
-	@echo \# Creating image [$(ARCH)]
+$(IMAGE).elf: $(OBJS) $(LIBS)
 	@echo + LD "->" $(IMAGE_REL).elf
-ifneq ($(filter $(ARCH),native),)
-	@$(CXX) -o $@ -Wl,--whole-archive $(LINKAGE) -Wl,-no-whole-archive $(LDFLAGS_CXX)
-else
-	@$(LD) $(LDFLAGS) -o $@ --start-group $(LINKAGE) --end-group
-endif
+	@$(LD) $(LDFLAGS) -o $(IMAGE).elf --start-group $(LINKAGE) --end-group
 
 ### Rule (archive): objects (`*.o`) -> `ARCHIVE.a` (ar)
 $(ARCHIVE): $(OBJS)
 	@echo + AR "->" $(shell realpath $@ --relative-to .)
-	@$(AR) rcs $@ $^
+	@$(AR) rcs $(ARCHIVE) $(OBJS)
 
 ### Rule (`#include` dependencies): paste in `.d` files generated by gcc on `-MMD`
 -include $(addprefix $(DST_DIR)/, $(addsuffix .d, $(basename $(SRCS))))
@@ -145,8 +147,8 @@ $(ARCHIVE): $(OBJS)
 ### Build order control
 image: image-dep
 archive: $(ARCHIVE)
-image-dep: $(LIBS) $(IMAGE).elf
-.NOTPARALLEL: image-dep
+image-dep: $(OBJS) $(LIBS)
+	@echo \# Creating image [$(ARCH)]
 .PHONY: image image-dep archive run $(LIBS)
 
 ### Clean a single project (remove `build/`)
@@ -158,5 +160,5 @@ clean:
 CLEAN_ALL = $(dir $(shell find . -mindepth 2 -name Makefile))
 clean-all: $(CLEAN_ALL) clean
 $(CLEAN_ALL):
-	-@$(MAKE) -s -C $@ clean
-.PHONY: clean-all $(CLEAN_ALL)
+	-@$(MAKE) -s -C $@ cleaear
+