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Suppress unhelpful gcc-7 warnings for now

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gcc-7 warning -Wformat-truncation would be good to fix, but the compiler
does not offer an acceptable solution yet.

gcc-7 warning -Wimplicit-fallthrough requires more analysis of the
diagnosed sites to identify which, if any, require a resolution other
than suppressing the warning.
This commit is contained in:
Kp 2017-06-10 03:31:04 +00:00
parent 4e578df4c6
commit 73057ad8ec
1 changed files with 38 additions and 0 deletions
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@ -2369,6 +2369,44 @@ where the cast is useless.
'-Wsuggest-attribute=noreturn',
'-Wlogical-op',
'-Wold-style-cast',
# Starting in gcc-7, Rebirth default options cause gcc to enable
# -Wformat-truncation automatically. Unless proven otherwise by
# data flow analysis, gcc pessimistically assumes that input
# parameters might have their most space-consuming value (3
# digits for a uint8_t, 5 for uint16_t, etc.). This causes
# numerous warnings for places where Rebirth allocated a buffer
# that is exactly big enough for the small numbers that are
# actually used, but the data flow analysis is unable to prove
# that larger numbers are not used.
#
# It would be nice to remove this option and eliminate the
# warnings with fixes in the code, since this test completely
# suppresses all -Wformat-truncation diagnostics, including any
# that may be true bugs. However, gcc provides no documented
# way to do this that does not generate extra runtime
# instructions, which are unnecessary in at least some of the
# cases where gcc warns.
#
# In testing, setting -Wformat-truncation=1 was insufficient to
# silence a warning in similar/main/net_udp.cpp:
#
# similar/main/net_udp.cpp: In static member function 'static void {anonymous}::more_game_options_menu_items::net_udp_more_game_options()':
# similar/main/net_udp.cpp:3528:6: error: ' Furthest Sites' directive output may be truncated writing 15 bytes into a region of size between 14 and 16 [-Werror=format-truncation=]
# void more_game_options_menu_items::net_udp_more_game_options()
# ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
# similar/main/net_udp.cpp:3433:11: note: 'snprintf' output between 21 and 23 bytes into a destination of size 21
# snprintf(SecludedSpawnText, sizeof(SecludedSpawnText), "Use %u Furthest Sites", Netgame.SecludedSpawns + 1);
# ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#
'-Wno-format-truncation',
# gcc-7 with -Wextra enables -Wimplicit-fallthrough, which warns
# for various sites in Rebirth. All the sites where fallthrough
# is obviously correct are already marked to suppress this
# warning, but sites which require analysis are not yet marked.
# Suppress this warning for the benefit of users who want a
# clean `-Wall -Wextra -Werror` build. At some point, this
# suppression should be removed and the remaining sites fixed.
'-Wno-implicit-fallthrough',
]
__preferred_win32_linker_options = [
'-Wl,--large-address-aware',