Fix parser/lexer generation with parallel make

Fun fact: rules with multiple targets don't work properly with 'make
-j'. For example, a rule like

  a b: c
    touch a b

is equivalent to

  a: c
    touch a b

  b: c
    touch a b

so with 'make -j', the 'touch' command will be run twice. See
e.g. https://stackoverflow.com/questions/2973445/gnu-makefile-rule-generating-a-few-targets-from-a-single-source-file.
This commit is contained in:
Eelco Dolstra 2018-08-17 12:59:23 +02:00
parent 19265ed26c
commit d277442df5
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1 changed files with 6 additions and 2 deletions

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@ -20,10 +20,14 @@ libexpr_LDFLAGS_PROPAGATED = $(BDW_GC_LIBS)
libexpr_ORDER_AFTER := $(d)/parser-tab.cc $(d)/parser-tab.hh $(d)/lexer-tab.cc $(d)/lexer-tab.hh
$(d)/parser-tab.cc $(d)/parser-tab.hh: $(d)/parser.y
$(d)/parser-tab.hh: $(d)/parser-tab.cc
$(d)/parser-tab.cc: $(d)/parser.y
$(trace-gen) bison -v -o $(libexpr_DIR)/parser-tab.cc $< -d
$(d)/lexer-tab.cc $(d)/lexer-tab.hh: $(d)/lexer.l
$(d)/lexer-tab.hh: $(d)/lexer-tab.cc
$(d)/lexer-tab.cc: $(d)/lexer.l
$(trace-gen) flex --outfile $(libexpr_DIR)/lexer-tab.cc --header-file=$(libexpr_DIR)/lexer-tab.hh $<
clean-files += $(d)/parser-tab.cc $(d)/parser-tab.hh $(d)/lexer-tab.cc $(d)/lexer-tab.hh