CODEWITHSUNDEEP
makefilegnu-make
Toby Cronin
Toby Cronin

Reputation: 558

Makefile error, can't resolve include

I'm working with a project using flex/bison and trying to compile it using make. The lex.yy.c, tab.c, tab.h from flex/bison are generated correctly and placed in the obj directory. However, there is an error when trying to compile the obj/lex.yy.c file and it cannot resolve an include to a file in the src/frontend directory. Any ideas where I am going wrong? Makefile and output included below.

Makefile:

VPATH = src obj src/frontend src/interpreter
SRCS = lex.yy.c C.tab.c symbol_table.c nodes.c print_ast.c interpreter.c main.c
OBJS := $(SRCS:%.c=obj/%.o)
INCLUDES = -Isrc -Iobj -Isrc/frontend -Isrc/interpreter
CPPFLAGS = -Wall
LDFLAGS = -Wall
CC = gcc
LEX = flex
YACC = bison -d -t -v

all: bin/mycc

bin/mycc: $(OBJS)
    $(CC) -g $(LDFLAGS) $(INCLUDES) -o $@ $^

obj/lex.yy.c: C.flex obj/C.tab.h
    $(LEX) -o $@ $<

obj/C.tab.c: C.y
    $(YACC) -o $@ $<

obj/C.tab.h: obj/C.tab.c
    @touch $@

obj/%.o: src/%.c
    $(CC) -g $(CPPFLAGS) $(INCLUDES) -c $^

clean: 
    rm $(OBJS) obj/lex.yy.c obj/C.tab.c obj/C.tab.h

depend: 
    $(CC) -M $(SRCS) > .deps
    cat Makefile .deps > makefile

Output:

bison -d -t -v -o obj/C.tab.c src/frontend/C.y
src/frontend/C.y: conflicts: 4 shift/reduce, 14 reduce/reduce
src/frontend/C.y:248.11-53: warning: rule useless in parser due to conflicts: external_declaration: function_definition
flex -o obj/lex.yy.c src/frontend/C.flex
gcc  -Wall  -c -o obj/lex.yy.o obj/lex.yy.c
src/frontend/C.flex:13:19: fatal error: token.h: No such file or directory
 #include "token.h"
               ^
compilation terminated.
make: *** [obj/lex.yy.o] Error 1

Upvotes: 0

Views: 1936

Answers (1)

Chris Dodd
Chris Dodd

Reputation: 126110

The problem is that you define your -I flags for compiling in the variable $(INCLUDES) instead of in the normal $(CPPFLAGS). As a result, when the default rule for compiling C files runs, it does not use any of those -I flags and so the compiler can't find the include files. You can see the command line for the compiler in your output.

To fix it, get rid of the INCLUDES = line and add all of them to CPPFLAGS:

CPPFLAGS = -Wall -Isrc -Iobj -Isrc/frontend -Isrc/interpreter

Upvotes: 1

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