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Start selectively disabling a few kernel build warnings for clang, since

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there are some places in the kernel where fixing them is too disruptive,
or where there is a false positive.

In this case, disable -Wconstant-conversion for two aic7xxx-related
files, as they get the following warning on i386 (and possibly on other
32-bit arches):

sys/dev/aic7xxx/ahc_pci.c:112:10: warning: implicit conversion from 'long long' to 'bus_addr_t' (aka 'unsigned int') changes value from 549755813887 to 4294967295 [-Wconstant-conversion]
                                   ? 0x7FFFFFFFFFLL
                                   ~~^~~~~~~~~~~~~~

This is a false positive, since the code only passes the 0x7FFFFFFFFFLL
argument, if sizeof(bus_addr_t) is larger than 4 (e.g. on 64 bit arches,
or when PAE is enabled on i386).  The code could be refactored to do
compile-time checks, but that is more disruptive.

MFC after:	1 week
This commit is contained in:
dim 2011-12-21 15:59:18 +00:00
parent ddda7a7681
commit d9a69f25c9
2 changed files with 11 additions and 2 deletions
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6
sys/conf/files
View File

@ -508,8 +508,10 @@ dev/aic/aic.c optional aic
dev/aic/aic_pccard.c optional aic pccard
dev/aic7xxx/ahc_eisa.c optional ahc eisa
dev/aic7xxx/ahc_isa.c optional ahc isa
dev/aic7xxx/ahc_pci.c optional ahc pci
dev/aic7xxx/ahd_pci.c optional ahd pci
dev/aic7xxx/ahc_pci.c optional ahc pci \
compile-with "${NORMAL_C} ${NO_WCONSTANT_CONVERSION}"
dev/aic7xxx/ahd_pci.c optional ahd pci \
compile-with "${NORMAL_C} ${NO_WCONSTANT_CONVERSION}"
dev/aic7xxx/aic7770.c optional ahc
dev/aic7xxx/aic79xx.c optional ahd pci
dev/aic7xxx/aic79xx_osm.c optional ahd pci

7
sys/conf/kern.mk
View File

@ -11,6 +11,13 @@ CWARNFLAGS?= -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
# The following flags are next up for working on:
# -Wextra
# Disable a few warnings for clang, since there are several places in the
# kernel where fixing them is more trouble than it is worth, or where there is
# a false positive.
.if ${CC:T:Mclang} == "clang"
NO_WCONSTANT_CONVERSION= -Wno-constant-conversion
.endif
#
# On i386, do not align the stack to 16-byte boundaries. Otherwise GCC 2.95
# and above adds code to the entry and exit point of every function to align the