Re: Build regressions/improvements in v4.9-rc1

Thomas Petazzoni
2016-10-27T14:52:14Z

Hello,

On Thu, 27 Oct 2016 11:32:11 +0200, Arnd Bergmann wrote:

> A couple of other architectures do this as well:
>
> $ git grep -w LIBGCC arch/*/Makefile
> arch/arc/Makefile:LIBGCC := $(shell $(CC) $(cflags-y) --print-libgcc-file-name)
> arch/arc/Makefile:libs-y += arch/arc/lib/ $(LIBGCC)
> arch/cris/Makefile:LIBGCC = $(shell $(CC) $(KBUILD_CFLAGS) -print-file-name=libgcc.a)
> arch/cris/Makefile:libs-y += arch/cris/$(SARCH)/lib/ $(LIBGCC)
> arch/hexagon/Makefile:LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
> arch/hexagon/Makefile:libs-y += $(LIBGCC)
> arch/m32r/Makefile:LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
> arch/m32r/Makefile:libs-y += arch/m32r/lib/ $(LIBGCC)
> arch/nios2/Makefile:LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) $(KCFLAGS) -print-libgcc-file-name)
> arch/nios2/Makefile:libs-y += arch/nios2/lib/ $(LIBGCC)
> arch/openrisc/Makefile:LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
> arch/openrisc/Makefile:libs-y += $(LIBGCC)
> arch/parisc/Makefile:LIBGCC = $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
> arch/parisc/Makefile:libs-y += arch/parisc/lib/ $(LIBGCC)
> arch/xtensa/Makefile:LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
> arch/xtensa/Makefile:libs-y += arch/xtensa/lib/ $(LIBGCC)
>
> It's also not always freestanding on the architectures that don't
> include libgcc:
>
> $ git grep ffreestanding arch/
> arch/mips/Makefile:cflags-y += -ffreestanding
> arch/s390/boot/compressed/Makefile:KBUILD_CFLAGS += $(call cc-option,-ffreestanding)
> arch/score/Makefile: -D__linux__ -ffunction-sections -ffreestanding
> arch/sh/Makefile:cflags-y += $(isaflags-y) -ffreestanding
> arch/x86/Makefile: KBUILD_CFLAGS += -ffreestanding # temporary until string.h is fixed
> arch/xtensa/Makefile:KBUILD_CFLAGS += -ffreestanding -D__linux__
>
> (xtensa being the only one that apparently uses libgcc *and* passes
> -ffreestanding, for whatever reasons).
>
> The other architectures tend to implement the parts of libgcc that they
> need in the kernel.

Thanks for the details, good to know!

Best regards,

Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering