https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65351
--- Comment #25 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #24)
> So perhaps for the top level something like:
yeah looks better than what i was drafting.
> --- config/mh-darwin 2013-09-30 22:13:57.243907474 +0200
> +++ config/mh-darwin 2015-04-08 10:36:58.100665592 +0200
> @@ -1,18 +1,29 @@
> # The -mdynamic-no-pic ensures that the compiler executable is built without
> # position-independent-code -- the usual default on Darwin. This fix speeds
> -# compiles by 3-5%.
> -BOOT_CFLAGS += \
> +# compiles by 3-5%. Don't add it if the compiler doesn't also support
> +# -mno-dynamic-no-pic to undo it.
> +DARWIN_MDYNAMIC_NO_PIC := \
> `case ${host} in i?86-*-darwin* | powerpc-*-darwin*) \
> - echo -mdynamic-no-pic ;; esac;`
> + $(CC) -S -xc /dev/null -o /dev/null -mno-dynamic-no-pic 2>/dev/null \
> + && echo -mdynamic-no-pic ;; esac`
> +DARWIN_GCC_MDYNAMIC_NO_PIC := \
> +`case ${host} in i?86-*-darwin* | powerpc-*-darwin*) \
> + $(CC) -S -xc /dev/null -o /dev/null -mno-dynamic-no-pic 2>/dev/null \
> + || echo -mdynamic-no-pic ;; esac`
I don't think we need the test here ^ ?
> # ld on Darwin versions >= 10.7 defaults to PIE executables. Disable this
> for
> # gcc components, since it is incompatible with our pch implementation.
> -BOOT_LDFLAGS += \
> -`case ${host} in *-*-darwin[1][1-9]*) echo -Wl,-no_pie ;; esac;`
> +DARWIN_NO_PIE := `case ${host} in *-*-darwin[1][1-9]*) echo -Wl,-no_pie ;;
> esac;`
> +
> +BOOT_CFLAGS += $(DARWIN_MDYNAMIC_NO_PIC)
> +BOOT_LDFLAGS += $(DARWIN_NO_PIE)
>
> # Similarly, for cross-compilation.
> -STAGE1_CFLAGS += \
> -`case ${host} in i?86-*-darwin* | powerpc-*-darwin*)\
> - echo -mdynamic-no-pic ;; esac;`
> -STAGE1_LDFLAGS += \
> -`case ${host} in *-*-darwin[1][1-9]*) echo -Wl,-no_pie ;; esac;`
> +STAGE1_CFLAGS += $(DARWIN_MDYNAMIC_NO_PIC)
> +STAGE1_LDFLAGS += $(DARWIN_NO_PIE)
> +
> +# Without -mno-dynamic-no-pic support, add -mdynamic-no-pic just to later
> +# stages when we know it is built with gcc.
> +STAGE2_CFLAGS += $(DARWIN_GCC_MDYNAMIC_NO_PIC)
> +STAGE3_CFLAGS += $(DARWIN_GCC_MDYNAMIC_NO_PIC)
> +STAGE4_CFLAGS += $(DARWIN_GCC_MDYNAMIC_NO_PIC)
>
> Thus, add -mdynamic-no-pic for gcc (or fixed clang) bootstrap compiler to
> BOOT_CFLAGS and STAGE1_CFLAGS, but only to STAGE{2,3,4}_CFLAGS otherwise?
>
> Then GCC_PICFLAG, being a configure snippet, can surely just use normal
> autoconfy way.
well, GCC_PICFLAG is not really very autoconf-y at present, just a bunch of
tests of triple. Will try to find some cycles later on.
