From: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
To: caiyinyu <caiyinyu@loongson.cn>,
libc-alpha@sourceware.org, joseph_myers@mentor.com,
carlos@redhat.com, i.swmail@xen0n.name, xry111@xry111.site
Cc: xuchenghua@loongson.cn
Subject: Re: [PATCH 1/2] LoongArch: Fix ptr mangling/demangling features.
Date: Thu, 25 Aug 2022 12:08:07 -0300 [thread overview]
Message-ID: <8562da19-d9d3-a4f3-2aae-2a4489af6806@linaro.org> (raw)
In-Reply-To: <20220823122833.1561228-2-caiyinyu@loongson.cn>
Does is really pay off the complexity to use HAVE_LOONGARCH_EXPLICIT_RELOCS? The
PTR_MANGLE is used some specific cases and hardly a hotstop.
On 23/08/22 09:28, caiyinyu wrote:
> Co-authored-by: Xi Ruoyao <xry111@xry111.site>
> ---
> sysdeps/loongarch/__longjmp.S | 2 +-
> sysdeps/loongarch/configure | 26 ++++++++++++++
> sysdeps/loongarch/configure.ac | 14 ++++++++
> sysdeps/loongarch/setjmp.S | 2 +-
> sysdeps/unix/sysv/linux/loongarch/sysdep.h | 40 +++++++++++++---------
> 5 files changed, 65 insertions(+), 19 deletions(-)
>
> diff --git a/sysdeps/loongarch/__longjmp.S b/sysdeps/loongarch/__longjmp.S
> index c2c5b56a80..4207376f5e 100644
> --- a/sysdeps/loongarch/__longjmp.S
> +++ b/sysdeps/loongarch/__longjmp.S
> @@ -22,7 +22,7 @@
> ENTRY (__longjmp)
> #ifdef PTR_MANGLE
> REG_L t0, a0, 0*SZREG
> - PTR_DEMANGLE (ra, t0, t1, t2)
> + PTR_DEMANGLE (ra, t0, t1)
> REG_L t0, a0, 1*SZREG
> PTR_DEMANGLE2 (sp, t0, t1)
> #else
> diff --git a/sysdeps/loongarch/configure b/sysdeps/loongarch/configure
> index 43b54d4965..54385786d2 100644
> --- a/sysdeps/loongarch/configure
> +++ b/sysdeps/loongarch/configure
> @@ -3,3 +3,29 @@
>
> $as_echo "#define HIDDEN_VAR_NEEDS_DYNAMIC_RELOC 1" >>confdefs.h
>
> +
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether explicit relocs can be used" >&5
> +$as_echo_n "checking whether explicit relocs can be used... " >&6; }
> +if ${libc_cv_loongarch_explicit_relocs+:} false; then :
> + $as_echo_n "(cached) " >&6
> +else
> + cat > conftest.s << EOF
> +x: pcalau12i \$t0, %pc_hi20(x)
> +EOF
> +libc_cv_loongarch_explicit_relocs=no
> +if { ac_try='${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&5'
> + { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
> + (eval $ac_try) 2>&5
> + ac_status=$?
> + $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
> + test $ac_status = 0; }; }; then
> + libc_cv_loongarch_explicit_relocs=yes
> +fi
> +rm -f conftest*
> +fi
> +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_loongarch_explicit_relocs" >&5
> +$as_echo "$libc_cv_loongarch_explicit_relocs" >&6; }
> +if test $libc_cv_loongarch_explicit_relocs = yes; then
> + $as_echo "#define HAVE_LOONGARCH_EXPLICIT_RELOCS 1" >>confdefs.h
> +
> +fi
> diff --git a/sysdeps/loongarch/configure.ac b/sysdeps/loongarch/configure.ac
> index f744367bf3..c5d3cb5ead 100644
> --- a/sysdeps/loongarch/configure.ac
> +++ b/sysdeps/loongarch/configure.ac
> @@ -4,3 +4,17 @@ GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
> dnl It is always possible to access static and hidden symbols in an
> dnl position independent way.
> AC_DEFINE(HIDDEN_VAR_NEEDS_DYNAMIC_RELOC)
> +
> +AC_CACHE_CHECK(whether explicit relocs can be used,
> + libc_cv_loongarch_explicit_relocs, [dnl
> +cat > conftest.s << EOF
> +x: pcalau12i \$t0, %pc_hi20(x)
> +EOF
> +libc_cv_loongarch_explicit_relocs=no
> +if AC_TRY_COMMAND(${CC-cc} -c $CFLAGS conftest.s -o conftest.o 1>&AS_MESSAGE_LOG_FD); then
> + libc_cv_loongarch_explicit_relocs=yes
> +fi
> +rm -f conftest*])
> +if test $libc_cv_loongarch_explicit_relocs = yes; then
> + AC_DEFINE(HAVE_LOONGARCH_EXPLICIT_RELOCS)
> +fi
> diff --git a/sysdeps/loongarch/setjmp.S b/sysdeps/loongarch/setjmp.S
> index ec4ddc72da..298bb02a82 100644
> --- a/sysdeps/loongarch/setjmp.S
> +++ b/sysdeps/loongarch/setjmp.S
> @@ -30,7 +30,7 @@ END (setjmp)
>
> ENTRY (__sigsetjmp)
> #ifdef PTR_MANGLE
> - PTR_MANGLE (t0, ra, t1, t2)
> + PTR_MANGLE (t0, ra, t1)
> REG_S t0, a0, 0*SZREG
> PTR_MANGLE2 (t0, sp, t1)
> REG_S t0, a0, 1*SZREG
> diff --git a/sysdeps/unix/sysv/linux/loongarch/sysdep.h b/sysdeps/unix/sysv/linux/loongarch/sysdep.h
> index 157cbd6c6b..0a8773c38d 100644
> --- a/sysdeps/unix/sysv/linux/loongarch/sysdep.h
> +++ b/sysdeps/unix/sysv/linux/loongarch/sysdep.h
> @@ -316,29 +316,35 @@ extern long int __syscall_error (long int neg_errno);
>
> /* Pointer mangling is supported for LoongArch. */
>
> -/* Load or store to/from a got-relative EXPR into/from G, using T.
> +/* Load a got-relative EXPR into G, using T.
> Note G and T are register names. */
> -#define LDST_GLOBAL(OP, G, T, EXPR) \
> - pcalau12i T, %got_pc_hi20(EXPR); \
> - OP T, T, %got_pc_lo12(EXPR); \
> - OP G, T, 0;
> +#define LD_GLOBAL(G, EXPR) \
> + la.global G, EXPR; \
> + REG_L G, G, 0;
>
> -/* Load or store to/from a pc-relative EXPR into/from G, using T.
> +/* Load a pc-relative EXPR into G, using T.
> Note G and T are register names. */
> -#define LDST_PCREL(OP, G, T, EXPR) \
> - pcalau12i T, %pc_hi20(EXPR); \
> - OP G, T, %pc_lo12(EXPR);
> +
> +#ifdef HAVE_LOONGARCH_EXPLICIT_RELOCS
> +#define LD_PCREL(G, EXPR) \
> + pcalau12i G, %pc_hi20(EXPR); \
> + REG_L G, G, %pc_lo12(EXPR);
> +#else
> +#define LD_PCREL(G, EXPR) \
> + la.pcrel G, EXPR; \
> + REG_L G, G, 0;
> +#endif
>
> #if (IS_IN (rtld) \
> || (!defined SHARED && (IS_IN (libc) \
> || IS_IN (libpthread))))
>
> #ifdef __ASSEMBLER__
> -#define PTR_MANGLE(dst, src, guard, tmp) \
> - LDST_PCREL (REG_L, guard, tmp, __pointer_chk_guard_local); \
> +#define PTR_MANGLE(dst, src, guard) \
> + LD_PCREL (guard, __pointer_chk_guard_local); \
> PTR_MANGLE2 (dst, src, guard);
> -#define PTR_DEMANGLE(dst, src, guard, tmp) \
> - LDST_PCREL (REG_L, guard, tmp, __pointer_chk_guard_local); \
> +#define PTR_DEMANGLE(dst, src, guard) \
> + LD_PCREL (guard, __pointer_chk_guard_local); \
> PTR_DEMANGLE2 (dst, src, guard);
> /* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
> #define PTR_MANGLE2(dst, src, guard) \
> @@ -355,11 +361,11 @@ extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
> #else
>
> #ifdef __ASSEMBLER__
> -#define PTR_MANGLE(dst, src, guard, tmp) \
> - LDST_GLOBAL (REG_L, guard, tmp, __pointer_chk_guard); \
> +#define PTR_MANGLE(dst, src, guard) \
> + LD_GLOBAL (guard, __pointer_chk_guard); \
> PTR_MANGLE2 (dst, src, guard);
> -#define PTR_DEMANGLE(dst, src, guard, tmp) \
> - LDST_GLOBAL (REG_L, guard, tmp, __pointer_chk_guard); \
> +#define PTR_DEMANGLE(dst, src, guard) \
> + LD_GLOBAL (guard, __pointer_chk_guard); \
> PTR_DEMANGLE2 (dst, src, guard);
> /* Use PTR_MANGLE2 for efficiency if guard is already loaded. */
> #define PTR_MANGLE2(dst, src, guard) \
next prev parent reply other threads:[~2022-08-25 15:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-23 12:28 [PATCH 0/2] " caiyinyu
2022-08-23 12:28 ` [PATCH 1/2] " caiyinyu
2022-08-25 15:08 ` Adhemerval Zanella Netto [this message]
2022-08-25 15:27 ` Xi Ruoyao
2022-08-25 17:01 ` Adhemerval Zanella Netto
2022-08-26 2:44 ` caiyinyu
2022-08-26 8:11 ` caiyinyu
2022-08-23 12:28 ` [PATCH 2/2] LoongArch: Add HAVE_LOONGARCH_EXPLICIT_RELOCS in config.h.in caiyinyu
2022-08-25 15:06 ` Adhemerval Zanella Netto
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