[PATCH v2 1/1] Makefile: enable --gc-sections

[Xiang W]

在 2024-08-29星期四的 20:12 +0000，Kele Zhang写道：
> The --gc-sections option enables the linker to perform garbage
> collection of unreferenced code and data, thereby reducing the binary
> size.
> 
> The -ffunction-sections option will place each function into a separate
> section, so it is necessary to add .text.* to the linker script.
> 
> Signed-off-by: Kele Zhang <zhangcola2003 at gmail.com>
> Signed-off-by: Yuan Tan <tanyuan at tinylab.org>
> Signed-off-by: Zhangjin Wu <falcon at tinylab.org>
LGTM

Reviewed-by: Xiang W <wxjstz at 126.com>
> ---
>  Makefile             | 5 +++--
>  firmware/fw_base.ldS | 1 +
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index e5a0f19..44db5d4 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -355,9 +355,9 @@ GENFLAGS	+=	$(libsbiutils-genflags-y)
>  GENFLAGS	+=	$(platform-genflags-y)
>  GENFLAGS	+=	$(firmware-genflags-y)
>  
> -CFLAGS		=	-g -Wall -Werror -ffreestanding -nostdlib -fno-stack-protector -fno-strict-aliasing
> +CFLAGS		=	-g -Wall -Werror -ffreestanding -nostdlib -fno-stack-protector -fno-strict-aliasing -ffunction-sections -fdata-
> sections
>  ifneq ($(DEBUG),)
> -CFLAGS		+=	-O0
> +CFLAGS		+=	-O0 -Wl,--print-gc-sections
>  else
>  CFLAGS		+=	-O2
>  endif
> @@ -406,6 +406,7 @@ ASFLAGS		+=	$(firmware-asflags-y)
>  ARFLAGS		=	rcs
>  
>  ELFFLAGS	+=	$(USE_LD_FLAG)
> +ELFFLAGS	+=	-Wl,--gc-sections
>  ifeq ($(OPENSBI_LD_EXCLUDE_LIBS),y)
>  ELFFLAGS	+=	-Wl,--exclude-libs,ALL
>  endif
> diff --git a/firmware/fw_base.ldS b/firmware/fw_base.ldS
> index fb47984..a33746a 100644
> --- a/firmware/fw_base.ldS
> +++ b/firmware/fw_base.ldS
> @@ -20,6 +20,7 @@
>  		PROVIDE(_text_start = .);
>  		*(.entry)
>  		*(.text)
> +		*(.text.*)
>  		. = ALIGN(8);
>  		PROVIDE(_text_end = .);
>  	}