1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
# -----------------------------------------------------------------------------
#
# (c) 2009 The University of Glasgow
#
# This file is part of the GHC build system.
#
# To understand how the build system works and how to modify it, see
# http://ghc.haskell.org/trac/ghc/wiki/Building/Architecture
# http://ghc.haskell.org/trac/ghc/wiki/Building/Modifying
#
# -----------------------------------------------------------------------------
define hs-suffix-way-rules # args: $1 = dir, $2 = distdir, $3 = way
ifeq "$3 $$($1_$2_DYNAMIC_TOO)" "dyn YES"
# We only want this rule to be used for Haskell sources, not for
# e.g. C sources, so we depend on the v_hisuf rather than v_osuf.
$1/$2/build/%.$$(dyn_osuf): $1/$2/build/%.$$(v_hisuf)
@if [ ! -f $$@ ] ; then \
echo "Panic! $$< exists, but $$@ does not."; \
exit 1; \
fi
$1/$2/build/%.$$(dyn_osuf)-boot: $1/$2/build/%.$$(v_hisuf)-boot
@if [ ! -f $$@ ] ; then \
echo "Panic! $$< exists, but $$@ does not."; \
exit 1; \
fi
else
# Note [Implicit rule search algorithm]
#
# The order in which implicit rules are defined can influence a build.
#
# Case study: genprimpos/Lexer.hs
#
# We have two implicit rules for creating .o files, which after instantiating
# with a specific directory ($1=utils/genprimops) and distdir ($2=dist) look
# like this:
#
# utils/genprimops/dist/build/%.o : utils/genprimops/dist/build/%.hs
# <recipe1>
# utils/genprimops/dist/build/%.o : utils/genprimops/./%.hs
# <recipe2>
#
# The first rule is defined in hs-suffix-way-rules.mk (this file), the other
# in hs-suffix-way-rules-srcdir.mk.
#
# Assume for rest of this story that %=Lexer.
#
# In a normal repository checkout, neither Lexer.hs exists, but we have a rule
# to generate the one in the build directory by running alex on Lexer.x (the
# rule for that operation is defined in hs-suffix-rules-srcdir.mk). Since make
# needs to make a choice which of the above two implicit rules to follow (it
# never runs 2 recipes for the same target, unless double colon rules are
# used, which we don't), logically it will choose the first rule: Lexer.o will
# depend on Lexer.hs in the build directory, that file will be build, and then
# Lexer.o can be build.
#
# In an sdist however, Lexer.hs is present in the source directory. It was
# copied there during the creation of the sdist by a rule in
# sdist-ghc-file.mk. And this time we *don't* know how to generate the
# Lexer.hs in the build directory, because 1) alex is not installed when
# building from sdist and 2) the sdist creation process renamed Lexer.x to
# Lexer.x.source. So normally make would now choose the second rule: Lexer.o
# will depend on Lexer.hs in the source directory, for which nothing needs to
# be done, and then Lexer.o can be build.
#
# There is however another actor in play, a rule in sdist-ghc-file.mk, which
# after after instantiating with the same directory ($1=utils/genprimops) and
# distdir ($2=dist) looks like this:
#
# sdist_utils/genprimops_dist_Lexer : utils/genprimops/dist/build/Lexer.hs
#
# Note that this is not an implicit rule, there aren't any %'s. This rule
# *explicitly* depends on Lexer.hs in the build directory. What follows is the
# following:
#
# * make thinks Lexer.hs in the build directory "ought to exist" [1],
# because it is an explicit dependency of /some/ target.
#
# * this puts our two implicit rules on equal footing: one depends on a
# file that exists, the other on a file that ought to exist. Make's
# implicit rule search algorithm doesn't distinguish between these two
# cases [1].
#
# * to break the tie, make chooses the rule that is defined first. Lexer.o
# will depend on Lexer.hs in the build directory, which doesn't exist,
# and which make doesn't know how to build, causing a build failure.
#
# To prevent this from happening we define rules for haskell source files in
# the source directory before those in the distdir.
#
# Alternative solutions:
#
# * Don't include the explicit rule above when not creating an sdist, as
# that is the only time when it is needed.
#
# * Merge the two implicit rules, with help from $1_$2_HS_SRCS from
# hs-sources.mk, which is sdist aware.
#
# * Require alex and happy to be installed when building from an sdist,
# simplifying all this drastically.
#
# [1] https://www.gnu.org/software/make/manual/make.html#Implicit-Rule-Search
$$(foreach dir,$$($1_$2_HS_SRC_DIRS),\
$$(eval $$(call hs-suffix-way-rules-srcdir,$1,$2,$3,$$(dir))))
ifneq "$$(BINDIST)" "YES"
$1/$2/build/%.$$($3_hcsuf) : $1/$2/build/%.hs $$(LAX_DEPS_FOLLOW) $$$$($1_$2_HC_DEP)
$$(call cmd,$1_$2_HC) $$($1_$2_$3_ALL_HC_OPTS) -C $$< -o $$@
$1/$2/build/%.$$($3_osuf) : $1/$2/build/%.hs $$(LAX_DEPS_FOLLOW) $$$$($1_$2_HC_DEP)
$$(call cmd,$1_$2_HC) $$($1_$2_$3_ALL_HC_OPTS) -c $$< -o $$@ $$(if $$(findstring YES,$$($1_$2_DYNAMIC_TOO)),-dyno $$(addsuffix .$$(dyn_osuf),$$(basename $$@)))
$1/$2/build/%.$$($3_hcsuf) : $1/$2/build/autogen/%.hs $$(LAX_DEPS_FOLLOW) $$$$($1_$2_HC_DEP)
$$(call cmd,$1_$2_HC) $$($1_$2_$3_ALL_HC_OPTS) -C $$< -o $$@
$1/$2/build/%.$$($3_osuf) : $1/$2/build/autogen/%.hs $$(LAX_DEPS_FOLLOW) $$$$($1_$2_HC_DEP)
$$(call cmd,$1_$2_HC) $$($1_$2_$3_ALL_HC_OPTS) -c $$< -o $$@ $$(if $$(findstring YES,$$($1_$2_DYNAMIC_TOO)),-dyno $$(addsuffix .$$(dyn_osuf),$$(basename $$@)))
endif
endif
endef # hs-suffix-way-rules
|
