[PATCH] RISC-V: Add -X to link spec

[PATCH] RISC-V: Add -X to link spec

[Fangrui Song]

From: Fangrui Song <maskray@gcc.gnu.org>

--discard-locals (-X) instructs the linker to remove local .L* symbols,
which occur a lot due to label differences for linker relaxation. The
arm port has a similar need and passes -X to ld.

In contrast, the RISC-V port does not pass -X to ld and rely on the
default --discard-locals in GNU ld's riscv port. The arm way is more
conventional (compiler driver instead of the linker customizes the
default behavior) and works with lld.
---
 gcc/config/riscv/elf.h     | 1 +
 gcc/config/riscv/freebsd.h | 1 +
 gcc/config/riscv/linux.h   | 1 +
 3 files changed, 3 insertions(+)

diff --git a/gcc/config/riscv/elf.h b/gcc/config/riscv/elf.h
index f533764d9f8..c97f13c0cca 100644
--- a/gcc/config/riscv/elf.h
+++ b/gcc/config/riscv/elf.h
@@ -20,6 +20,7 @@ along with GCC; see the file COPYING3.  If not see
 #define LINK_SPEC "\
 -melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv \
 %{mno-relax:--no-relax} \
+-X \
 %{mbig-endian:-EB} \
 %{mlittle-endian:-EL} \
 %{shared}"
diff --git a/gcc/config/riscv/freebsd.h b/gcc/config/riscv/freebsd.h
index bd08a985285..5dd4d51c42b 100644
--- a/gcc/config/riscv/freebsd.h
+++ b/gcc/config/riscv/freebsd.h
@@ -44,6 +44,7 @@ along with GCC; see the file COPYING3.  If not see
   %{p:%nconsider using `-pg' instead of `-p' with gprof (1)}	\
   %{v:-V}							\
   %{assert*} %{R*} %{rpath*} %{defsym*}				\
+  -X								\
   %{mbig-endian:-EB}						\
   %{mlittle-endian:-EL}						\
   %{shared:-Bshareable %{h*} %{soname*}}			\
diff --git a/gcc/config/riscv/linux.h b/gcc/config/riscv/linux.h
index 15851f653bc..3c356227134 100644
--- a/gcc/config/riscv/linux.h
+++ b/gcc/config/riscv/linux.h
@@ -50,6 +50,7 @@ along with GCC; see the file COPYING3.  If not see
 #define LINK_SPEC "\
 -melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
 %{mno-relax:--no-relax} \
+-X \
 %{mbig-endian:-EB} \
 %{mlittle-endian:-EL} \
 %{shared} \
-- 
2.44.0.769.g3c40516874-goog

Re: [PATCH] RISC-V: Add -X to link spec

[Kito Cheng]

[-- Attachment #1: Type: text/plain, Size: 2426 bytes --]

LGTM :)

Fangrui Song <maskray@google.com> 於 2024年4月23日 週二 12:27 寫道：

> From: Fangrui Song <maskray@gcc.gnu.org>
>
> --discard-locals (-X) instructs the linker to remove local .L* symbols,
> which occur a lot due to label differences for linker relaxation. The
> arm port has a similar need and passes -X to ld.
>
> In contrast, the RISC-V port does not pass -X to ld and rely on the
> default --discard-locals in GNU ld's riscv port. The arm way is more
> conventional (compiler driver instead of the linker customizes the
> default behavior) and works with lld.
> ---
>  gcc/config/riscv/elf.h     | 1 +
>  gcc/config/riscv/freebsd.h | 1 +
>  gcc/config/riscv/linux.h   | 1 +
>  3 files changed, 3 insertions(+)
>
> diff --git a/gcc/config/riscv/elf.h b/gcc/config/riscv/elf.h
> index f533764d9f8..c97f13c0cca 100644
> --- a/gcc/config/riscv/elf.h
> +++ b/gcc/config/riscv/elf.h
> @@ -20,6 +20,7 @@ along with GCC; see the file COPYING3.  If not see
>  #define LINK_SPEC "\
>  -melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv \
>  %{mno-relax:--no-relax} \
> +-X \
>  %{mbig-endian:-EB} \
>  %{mlittle-endian:-EL} \
>  %{shared}"
> diff --git a/gcc/config/riscv/freebsd.h b/gcc/config/riscv/freebsd.h
> index bd08a985285..5dd4d51c42b 100644
> --- a/gcc/config/riscv/freebsd.h
> +++ b/gcc/config/riscv/freebsd.h
> @@ -44,6 +44,7 @@ along with GCC; see the file COPYING3.  If not see
>    %{p:%nconsider using `-pg' instead of `-p' with gprof (1)}   \
>    %{v:-V}                                                      \
>    %{assert*} %{R*} %{rpath*} %{defsym*}                                \
> +  -X                                                           \
>    %{mbig-endian:-EB}                                           \
>    %{mlittle-endian:-EL}                                                \
>    %{shared:-Bshareable %{h*} %{soname*}}                       \
> diff --git a/gcc/config/riscv/linux.h b/gcc/config/riscv/linux.h
> index 15851f653bc..3c356227134 100644
> --- a/gcc/config/riscv/linux.h
> +++ b/gcc/config/riscv/linux.h
> @@ -50,6 +50,7 @@ along with GCC; see the file COPYING3.  If not see
>  #define LINK_SPEC "\
>  -melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
>  %{mno-relax:--no-relax} \
> +-X \
>  %{mbig-endian:-EB} \
>  %{mlittle-endian:-EL} \
>  %{shared} \
> --
> 2.44.0.769.g3c40516874-goog
>
>