| Message ID | 004ed61b6c6743ab87a369bc6202b4b1c50de89d.1724959010.git.zhangcola2003@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Enable Dead Code Elimination | expand |
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@gmail.com> > Signed-off-by: Yuan Tan <tanyuan@tinylab.org> > Signed-off-by: Zhangjin Wu <falcon@tinylab.org> LGTM Reviewed-by: Xiang W <wxjstz@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 = .); > }
On Fri, Aug 30, 2024 at 4:12 AM Kele Zhang <zhangcola2003@gmail.com> wrote: > > 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@gmail.com> > Signed-off-by: Yuan Tan <tanyuan@tinylab.org> > Signed-off-by: Zhangjin Wu <falcon@tinylab.org> > --- > 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 This should be put into the ELF flags too. > 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 = .); > } Regards, Bin
Bin Meng <bmeng.cn@gmail.com> 于2024年9月1日周日 19:12写道： > > On Fri, Aug 30, 2024 at 4:12 AM Kele Zhang <zhangcola2003@gmail.com> wrote: > > > > 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@gmail.com> > > Signed-off-by: Yuan Tan <tanyuan@tinylab.org> > > Signed-off-by: Zhangjin Wu <falcon@tinylab.org> > > --- > > 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 > > This should be put into the ELF flags too. Are ELFflags the flags that take effect during linking? -ffunction-sections -fdata-sections will take effect during compilation. Enabling them will generate different .s files and will not affect the behavior of the linker. So isn't it better to put them in cflags? > > > 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 = .); > > } > > Regards, > Bin
在 2024-09-01星期日的 19:51 +0800，cola zhang写道： > Bin Meng <bmeng.cn@gmail.com> 于2024年9月1日周日 19:12写道： > > > > On Fri, Aug 30, 2024 at 4:12 AM Kele Zhang <zhangcola2003@gmail.com> wrote: > > > > > > 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@gmail.com> > > > Signed-off-by: Yuan Tan <tanyuan@tinylab.org> > > > Signed-off-by: Zhangjin Wu <falcon@tinylab.org> > > > --- > > > 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 > > > > This should be put into the ELF flags too. > > Are ELFflags the flags that take effect during linking? > -ffunction-sections -fdata-sections will take effect during compilation. > Enabling them will generate different .s files and will not affect the behavior > of the linker. So isn't it better to put them in cflags? -Wl,--print-gc-sections move to ELFFLAGS Regards, Xiang W > > > > > > 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 = .); > > > } > > > > Regards, > > Bin
Xiang W <wxjstz@126.com> 于2024年9月1日周日 20:15写道： > > 在 2024-09-01星期日的 19:51 +0800，cola zhang写道： > > Bin Meng <bmeng.cn@gmail.com> 于2024年9月1日周日 19:12写道： > > > > > > On Fri, Aug 30, 2024 at 4:12 AM Kele Zhang <zhangcola2003@gmail.com> wrote: > > > > > > > > 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@gmail.com> > > > > Signed-off-by: Yuan Tan <tanyuan@tinylab.org> > > > > Signed-off-by: Zhangjin Wu <falcon@tinylab.org> > > > > --- > > > > 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 > > > > > > This should be put into the ELF flags too. > > > > Are ELFflags the flags that take effect during linking? > > -ffunction-sections -fdata-sections will take effect during compilation. > > Enabling them will generate different .s files and will not affect the behavior > > of the linker. So isn't it better to put them in cflags? > > -Wl,--print-gc-sections move to ELFFLAGS Sorry, I didn't see clearly. This indeed needs to be modified. > > Regards, > Xiang W > > > > > > > > > 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 = .); > > > > } > > > > > > Regards, > > > Bin >
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 = .); }