[PATCH 1/1] LoongArch: Fix ptr mangling/demangling features.
Xi Ruoyao
xry111@xry111.site
Sun Aug 21 13:29:07 GMT 2022
On Thu, 2022-08-18 at 10:19 +0800, caiyinyu wrote:
> -/* 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);
> +#define LD_PCREL(G, EXPR) \
> + la.pcrel G, EXPR; \
> + REG_L G, G, 0;
I'd write
#if HAVE_LOONGARCH_EXPLICIT_RELOCS
# define LDST_PCREL(OP, G, T, EXPR) \
pcalau12i T, %pc_hi20(EXPR); \
OP G, T, %pc_lo12(EXPR);
#else
# define LD_PCREL(G, EXPR) \
la.pcrel G, EXPR; \
REG_L G, G, 0;
#endif
And in configure.ac:
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
This is a micro optimization but two instructions is smaller than 3
instructions anyway :).
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
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