Re: Build failed on fresh sources

[christos%astron.com@localhost (Christos Zoulas)]

In article <CAGR2We1VeDTBrxGkUX_8zugYdcqxoDjPT58JLDgxsjWXzBF7Yg%mail.gmail.com@localhost>,
Greywolf  <relayer%gmail.com@localhost> wrote:
>Sources from 2019-09-26, building a kernel, I get this:
>
>###
>gcc -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -mno-avx
>-msoft-float -mindirect-branch=thunk-inline -mindirect-branch-register
>-ffreestanding -fno-zero-initialized-in-bss
>-fno-delete-null-pointer-checks -g -O2 -fno-omit-frame-pointer
>-fstack-protector -Wstack-protector --param ssp-buffer-size=1
>-fno-strict-aliasing -fno-common -std=gnu99 -Werror -Wall -Wno-main
>-Wno-format-zero-length -Wpointer-arith -Wmissing-prototypes
>-Wstrict-prototypes -Wold-style-definition -Wswitch -Wshadow
>-Wcast-qual -Wwrite-strings -Wno-unreachable-code -Wno-pointer-sign
>-Wno-attributes -Wextra -Wno-unused-parameter -Wold-style-definition
>-Wno-sign-compare -Wno-shadow -Damd64 -Dx86_64 -I.
>-I../../../../external/bsd/acpica/dist
>-I../../../../external/bsd/libnv/dist
>-I../../../../../common/lib/libx86emu
>-I../../../../../common/lib/libc/misc -I../../../../../common/include
>-I../../../../arch -I../../../.. -nostdinc -DCOMPAT_UTILS -DDIAGNOSTIC
>-DCOMPAT_44 -D_KERNEL -D_KERNEL_OPT -std=gnu99
>-I../../../../lib/libkern/../../../common/lib/libc/quad
>-I../../../../lib/libkern/../../../common/lib/libc/string
>-I../../../../lib/libkern/../../../common/lib/libc/arch/x86_64/string
>-D_FORTIFY_SOURCE=2 -I../../../../external/bsd/common/include
>-I../../../../external/bsd/common/include
>-I../../../../external/bsd/drm2/include
>-I../../../../external/bsd/drm2/include
>-I../../../../external/bsd/common/include
>-I../../../../external/bsd/drm2/dist/include
>-I../../../../external/bsd/drm2/dist/include/drm
>-I../../../../external/bsd/drm2/dist/uapi
>-I../../../../external/bsd/drm2/dist -D__KERNEL__
>-DCONFIG_BACKLIGHT_CLASS_DEVICE=0
>-DCONFIG_BACKLIGHT_CLASS_DEVICE_MODULE=0
>-DCONFIG_DRM_FBDEV_EMULATION=1 -DCONFIG_FB=0
>-I../../../../../common/include -I../../../../external/bsd/libnv/dist
>-I../../../../external/bsd/drm2/i915drm
>-I../../../../external/bsd/drm2/dist/drm/i915
>-DCONFIG_DRM_I915_FBDEV=1 -DCONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT=0
>-DCONFIG_DRM_FBDEV_EMULATION=1
>-I../../../../external/bsd/acpica/dist/include -c
>../../../../external/bsd/drm2/dist/drm/i915/intel_ddi.c -o intel_ddi.o
>In file included from
>../../../../external/bsd/drm2/dist/drm/i915/intel_bios.h:33:0,
>                 from ../../../../external/bsd/drm2/dist/drm/i915/i915_drv.h:50,
>                 from
>../../../../external/bsd/drm2/dist/drm/i915/intel_ddi.c:35:
>../../../../external/bsd/drm2/dist/drm/i915/intel_ddi.c: In function
>'translate_signal_level':
>../../../../external/bsd/drm2/dist/include/drm/drmP.h:241:6: error:
>this statement may fall through [-Werror=implicit-fallthrough=]
>   if (unlikely(drm_debug & DRM_UT_KMS))   \
>      ^
>../../../../external/bsd/drm2/dist/drm/i915/intel_ddi.c:2229:3: note:
>in expansion of macro 'DRM_DEBUG_KMS'
>   DRM_DEBUG_KMS("Unsupported voltage swing/pre-emphasis level: 0x%x\n",
>   ^~~~~~~~~~~~~
>../../../../external/bsd/drm2/dist/drm/i915/intel_ddi.c:2231:2: note: here
>  case DP_TRAIN_VOLTAGE_SWING_LEVEL_0 | DP_TRAIN_PRE_EMPH_LEVEL_0:
>  ^~~~
>cc1: all warnings being treated as errors
>*** Error code 1
>
>Stop.
>###
>
>It's one of a bug, a coding error, or user error.  I will accept all
>of these answers, but if it's the third one, I'd like to know where
>I've gone wrong.

We've chosen not to fix the fallthrough warnings in 3rd party code, but
we instead have changed the default setting to not produce errors. Have
you made any changes to the compilation environment that caused those to
become errors again?

christos