On 2/15/19 6:22 PM, Ramsay Jones wrote: > > > On 15/02/2019 08:34, Uwe Kleine-König wrote: > [snip] >> I use CC = gcc-8 for the debian package because other it can happen (and >> it actually did) that /usr/bin/gcc was updated from gcc-X to gcc-(X+1) >> and then sparse started to fail because it still used >> /usr/lib/gcc/x86_64-linux-gnu/X/ (i.e. the output of >> >> gcc --print-file-name= >> >> ) which disappeard as it changes on major version bumps. >> >> So sparse depends explicitly on the current gcc version and uses this. > > Hmm, yes, sparse may well depend a little too much on gcc. ;-) > > Having said that, these values built-in to sparse are just > default values that can be set from the command-line of > sparse (see -gcc-base-dir and -multiarch-dir). Indeed they > _are_ set by cgcc by running the 'specified c compiler' at > each invocation, if not _also_ specified on the cgcc command > line. > > Hmm, do you remember how/what failed? (I suppose this was not > a kernel usage). Right. The problem was https://bugs.debian.org/906472 . In short, Makefile has: GCC_BASE := $(shell $(CC) --print-file-name=) cflags += -DGCC_BASE=\"$(GCC_BASE)\" which is then used in lib.c to find some header files. The version of sparse that #906472 was reported against was build with gcc-7, so sparse used /usr/lib/gcc/x86_64-linux-gnu/7/ on amd64. Then when gcc-7 wasn't installed (gcc was provided by gcc-8) sparse failed to check userspace code because the gcc headers were not found. Best regards Uwe
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