Add separate rules for all .hi files, rather than using %.hi style

If a file is created by a %.hi rule, and the actual filename isn't
mentioned in the makefiles, then make will treat it as an 'intermediate
file' and delete it when it is finished.

We'd been lucky so far that .hi files weren't actually being built due
to our rules (but rather, as side-effects of the .o rules). However,
when using -dynamic-too to build, we had a rule
    $1/$2/build/%.$$(dyn_osuf): $1/$2/build/%.$$(v_hisuf)
which meant that building a .dyn_o could cause the rule for the
corresponding .hi to be used, and the .hi may then be deleted later on.
This was exacerbated by a bug in GNU make 3.81 which caused make to
enter an infinite loop if running in parallel mode:
    http://lists.gnu.org/archive/html/bug-make/2013-02/msg00020.html

Adding
    .SECONDARY:
would stop make from deleting the intermediate files. However, this
caused make to take a pathologically long time (it appeared to be
live-locked for 2 hours before I killed it) with our build system.

This patch instead creates lines like
    $(eval $(call hi-rule,libraries/base/dist-install/build/Unsafe/Coerce.dyn_hi libraries/base/dist-install/build/Unsafe/Coerce.hi  : %hi: %o  libraries/base/Unsafe/Coerce.hs))
in the .depend files, which results in a rule like
    libraries/base/dist-install/build/Unsafe/Coerce.dyn_hi libraries/base/dist-install/build/Unsafe/Coerce.hi  : %hi: %o  libraries/base/Unsafe/Coerce.hs ;
which, as the files are now all named in the makefiles, means they are
no longer intermediate files so do not get deleted.

3 files changed, 4 insertions, 18 deletions

diff --git a/rules/build-dependencies.mk b/rules/build-dependencies.mk
index 4a4f5638e2..346ee10148 100644
--- a/rules/build-dependencies.mk
+++ b/rules/build-dependencies.mk
@@ -48,7 +48,8 @@ endif
 #    Some packages are from the bootstrapping compiler, so are not
 #    within the build tree. On Windows this causes a problem as they look
 #    like bad rules, due to the two colons, so we filter them out.
-	grep -v ' : [a-zA-Z]:/' $$@.tmp > $$@
+	grep -v ' : [a-zA-Z]:/' $$@.tmp > $$@.tmp2
+	sed '/hs$$$$/ { p; s/o /hi /g; s/:/ : %hi: %o /; s/^/$$$$(eval $$$$(call hi-rule,/; s/$$$$/))/ }; /hs-boot$$$$/ { p; s/o-boot /hi-boot /g; s/:/ : %hi-boot: %o-boot /; s/^/$$$$(eval $$$$(call hi-rule,/; s/$$$$/))/ }' $$@.tmp2 > $$@
 
 # Some of the C files (directly or indirectly) include the generated
 # includes files.
diff --git a/rules/hi-rule.mk b/rules/hi-rule.mk
index e478c17aea..a343389967 100644
--- a/rules/hi-rule.mk
+++ b/rules/hi-rule.mk
@@ -71,25 +71,15 @@
 #
 # a/%.hi : a/%.o b/%.hs ;
 
-define hi-rule # $1 = source directory, $2 = object directory, $3 = way
-
-$(call hi-rule-helper,$2/%.$$($3_hisuf) : $2/%.$$($3_osuf) $1/%.hs)
-$(call hi-rule-helper,$2/%.$$($3_hisuf) : $2/%.$$($3_osuf) $1/%.lhs)
-
-$(call hi-rule-helper,$2/%.$$($3_way_)hi-boot : $2/%.$$($3_way_)o-boot $1/%.hs)
-$(call hi-rule-helper,$2/%.$$($3_way_)hi-boot : $2/%.$$($3_way_)o-boot $1/%.lhs)
-
-endef
-
 ifeq "$(ExtraMakefileSanityChecks)" "NO"
 
-define hi-rule-helper # $1 = rule header
+define hi-rule # $1 = rule header
 $1 ;
 endef
 
 else
 
-define hi-rule-helper # $1 = rule header
+define hi-rule # $1 = rule header
 $1
 	@if [ ! -f $$@ ] ; then \
 	    echo "Panic! $$< exists, but $$@ does not."; \
diff --git a/rules/hs-suffix-way-rules.mk b/rules/hs-suffix-way-rules.mk
index bfab91227d..884ed7009f 100644
--- a/rules/hs-suffix-way-rules.mk
+++ b/rules/hs-suffix-way-rules.mk
@@ -32,10 +32,5 @@ endif
 $$(foreach dir,$$($1_$2_HS_SRC_DIRS),\
   $$(eval $$(call hs-suffix-way-rules-srcdir,$1,$2,$3,$$(dir))))
 
-$(call hi-rule,$1/$2/build,$1/$2/build,$3)
-$(call hi-rule,$1/$2/build/autogen,$1/$2/build,$3)
-$$(foreach dir,$$($1_$2_HS_SRC_DIRS),\
-  $$(eval $$(call hi-rule,$1/$$(dir),$1/$2/build,$3)))
-
 endef # hs-suffix-way-rules