Update autoconf test for gcc to require 4.7 and up
[ghc.git] / mk / warnings.mk
1 # See Note [Order of warning flags].
2 SRC_CC_OPTS += -Wall $(WERROR)
3 SRC_HC_OPTS += -Wall
4 # Don't add -Werror to SRC_HC_OPTS_STAGE0 (or SRC_HC_OPTS), because otherwise
5 # validate may unnecessarily fail when booting with an older compiler.
6 # It would be better to only exclude certain warnings from becoming errors
7 # (e.g. '-Werror -Wno-error=unused-imports -Wno-error=...'), but -Wno-error
8 # isn't supported yet (https://ghc.haskell.org/trac/ghc/wiki/Design/Warnings).
9 #
10 # See Note [Stage number in build variables] in mk/config.mk.in.
11 SRC_HC_OPTS_STAGE1 += $(WERROR)
12 SRC_HC_OPTS_STAGE2 += $(WERROR)
13
14 # Enable -Wcpp-undef for GHC components only as we don't (currently) expect core
15 # libraries to build in this configuration (see #13636).
16 GhcRtsHcOpts += -Wcpp-undef
17 GhcStage1HcOpts += -Wcpp-undef
18 GhcStage2HcOpts += -Wcpp-undef
19
20 ifneq "$(GccIsClang)" "YES"
21
22 # Debian doesn't turn -Werror=unused-but-set-variable on by default, so
23 # we turn it on explicitly for consistency with other users.
24 # Never set the flag on Windows as the host gcc may be too old.
25 ifneq "$(HostOS_CPP)" "mingw32"
26 SRC_CC_WARNING_OPTS += -Werror=unused-but-set-variable
27 endif
28
29 # Suppress the warning about __sync_fetch_and_nand (#9678).
30 libraries/ghc-prim/cbits/atomic_CC_OPTS += -Wno-sync-nand
31 # gcc 4.6 gives 3 warnings for giveCapabilityToTask not being inlined
32 # gcc 4.4 gives 2 warnings for lockClosure not being inlined
33 SRC_CC_WARNING_OPTS += -Wno-error=inline
34
35 else
36
37 # Don't warn about unknown GCC pragmas when using clang
38 SRC_CC_WARNING_OPTS += -Wno-unknown-pragmas
39
40 endif
41
42 SRC_HC_WARNING_OPTS_STAGE1 += -Wnoncanonical-monad-instances
43 SRC_HC_WARNING_OPTS_STAGE2 += -Wnoncanonical-monad-instances
44
45
46 ######################################################################
47 # Disable some warnings in packages we use
48
49 # NB: The GHC version used for bootstrapping may not support the
50 # `-W`-aliases for `-f(no-)warn` flags introduced in GHC 8.0, so in
51 # some cases (watch out for make-variables with a name containing
52 # "boot") we need to pass the legacy `-f(no-)warn`-flags instead.
53
54 # Libraries that have dubious RULES
55 libraries/bytestring_dist-install_EXTRA_HC_OPTS += -Wno-inline-rule-shadowing
56
57 # Turn off import warnings for bad unused imports
58 utils/haddock_dist_EXTRA_HC_OPTS += -Wno-unused-imports
59 libraries/vector_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
60 libraries/directory_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
61
62 # haddock's attoparsec uses deprecated `inlinePerformIO`
63 utils/haddock_dist_EXTRA_HC_OPTS += -Wno-deprecations
64 # binary too
65 libraries/binary_dist-install_EXTRA_HC_OPTS += -Wno-deprecations
66
67 # On Windows, there are/were some unused import warnings
68 ifeq "$(HostOS_CPP)" "mingw32"
69 libraries/time_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports -Wno-identities
70 endif
71
72 # On Windows, the pattern for CallConv is already exaustive. Ignore the warning
73 ifeq "$(HostOS_CPP)" "mingw32"
74 libraries/ghci_dist-install_EXTRA_HC_OPTS += -Wno-overlapping-patterns
75 endif
76
77 # haskeline has warnings about deprecated use of block/unblock
78 libraries/haskeline_dist-install_EXTRA_HC_OPTS += -Wno-deprecations
79 libraries/haskeline_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
80 libraries/haskeline_dist-install_EXTRA_HC_OPTS += -Wno-redundant-constraints
81 libraries/haskeline_dist-install_EXTRA_HC_OPTS += -Wno-simplifiable-class-constraints
82
83
84 # temporarily turn off unused-imports warnings for pretty
85 libraries/pretty_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
86
87 # primitive has a warning about deprecated use of GHC.IOBase
88 libraries/primitive_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
89 # primitive uses deprecated Control.Monad.Trans.Error
90 libraries/primitive_dist-install_EXTRA_HC_OPTS += -Wno-deprecations
91
92 # See https://github.com/haskell/random/pull/20
93 libraries/random_dist-install_EXTRA_HC_OPTS += -Wno-redundant-constraints
94
95 # temporarily turn off unused-imports warnings for terminfo
96 libraries/terminfo_dist-boot_EXTRA_HC_OPTS += -fno-warn-unused-imports
97 libraries/terminfo_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
98
99 # vector has some unused match warnings
100 libraries/vector_dist-install_EXTRA_HC_OPTS += -Wwarn
101
102 # temporarily turn off unused-imports warnings for xhtml
103 libraries/xhtml_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
104 libraries/xhtml_dist-install_EXTRA_HC_OPTS += -Wno-tabs
105
106 libraries/dph/dph-base_dist-install_EXTRA_HC_OPTS += -Wwarn
107 libraries/dph/dph-prim-interface_dist-install_EXTRA_HC_OPTS += -Wwarn
108 libraries/dph/dph-prim-seq_dist-install_EXTRA_HC_OPTS += -Wwarn
109 libraries/dph/dph-prim-par_dist-install_EXTRA_HC_OPTS += -Wwarn
110 libraries/dph/dph-lifted-common-install_EXTRA_HC_OPTS += -Wwarn
111
112 # transformers has unused function parameters warnings
113 libraries/transformers_dist-boot_EXTRA_HC_OPTS += -fno-warn-unused-matches -fno-warn-unused-imports
114 libraries/transformers_dist-install_EXTRA_HC_OPTS += -Wno-unused-matches -Wno-unused-imports
115 libraries/transformers_dist-install_EXTRA_HC_OPTS += -Wno-redundant-constraints
116 libraries/transformers_dist-install_EXTRA_HC_OPTS += -Wno-orphans
117
118 # parsec has various warnings
119 libraries/parsec_dist-install_EXTRA_HC_OPTS += -Wno-name-shadowing -Wno-unused-matches
120 libraries/parsec_dist-install_EXTRA_HC_OPTS += -Wno-unused-do-bind -Wno-missing-signatures
121 libraries/parsec_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports -Wno-type-defaults
122
123 # Turn of trustworthy-safe warning
124 libraries/base_dist-install_EXTRA_HC_OPTS += -Wno-trustworthy-safe
125 libraries/ghc-prim_dist-install_EXTRA_HC_OPTS += -Wno-trustworthy-safe
126 libraries/Win32_dist-install_EXTRA_HC_OPTS += -Wno-trustworthy-safe
127
128 # We need -Wno-deprecated-flags to avoid failure with -Werror
129 GhcLibExtraHcOpts += -Wno-deprecated-flags
130 GhcBootLibExtraHcOpts += -fno-warn-deprecated-flags
131
132 # Note [Order of warning flags]
133 #
134 # In distdir-way-opts, build flags are added in the following order (this
135 # list is not exhaustive):
136 #
137 # * SRC_HC_OPTS(_STAGE$4)
138 # * ghc-options from .cabal files ($1_$2_HC_OPTS)
139 # * SRC_HC_WARNING_OPTS(_STAGE$4)
140 #
141 # Considerations:
142 #
143 # * Most .cabal files specify -Wall. But not all, and not all building we
144 # do relies on .cabal files. So we have to add -Wall ourselves somewhere.
145 #
146 # * Some .cabal also specify warning suppression flags. Because -Wall
147 # overrides any warning suppression flags that come before it, we have to
148 # make sure -Wall comes before any warning suppression flags. So we add it
149 # to SRC_HC_OPTS.
150 #
151 # * Similarly, our own warning suppression should come after the -Wall from
152 # the .cabal files, so we do *not* add them to SRC_HC_OPTS.