makefile: canonicalize path when compiling

Compilers store the path with which they were called in the debug
symbols. Therefore, this will make backtraces show something like
../i3-4.2/src/main.c instead of src/main.c.

See also http://stackoverflow.com/questions/6473561/

diff --git a/src/i3.mk b/src/i3.mk
index 8c85e31d1b0062e1b980ee20072985ccdd233b18..f997c821ab4dd6eaec1ad6889951f7ccc73dd046 100644 (file)
--- a/src/i3.mk
+++ b/src/i3.mk
@@ -21,21 +21,29 @@ endif
 
 i3_OBJECTS := $(i3_SOURCES_GENERATED:.c=.o) $(i3_SOURCES:.c=.o)
 
+# The basename/readlink calls are for canonicalizing the path: Instead
+# of src/main.c, we will see something like ../i3-4.2/src/main.c in
+# debugger backtraces, making it clearer which code belongs to i3 and
+# which code doesn’t.
+# We only do this for src/ since all the other subdirectories contain i3 in
+# their name already.
+canonical_path := ../$(shell basename $(shell readlink -f .))
+
 include/all.h.pch: $(i3_HEADERS)
        echo "[i3] PCH all.h"
        $(CC) $(I3_CPPFLAGS) $(CPPFLAGS) $(i3_CFLAGS) $(I3_CFLAGS) $(CFLAGS) -x c-header include/all.h -o include/all.h.pch
 
 src/%.o: src/%.c $(i3_HEADERS_DEP)
        echo "[i3] CC $<"
-       $(CC) $(I3_CPPFLAGS) $(CPPFLAGS) $(i3_CFLAGS) $(I3_CFLAGS) $(CFLAGS) $(PCH_FLAGS) -c -o $@ $<
+       $(CC) $(I3_CPPFLAGS) $(CPPFLAGS) $(i3_CFLAGS) $(I3_CFLAGS) $(CFLAGS) $(PCH_FLAGS) -c -o $@ ${canonical_path}/$<
 
 src/cfgparse.yy.c: src/cfgparse.l src/cfgparse.tab.o $(i3_HEADERS_DEP)
        echo "[i3] LEX $<"
-       $(FLEX) -i -o $@ $<
+       $(FLEX) -i -o $@ ${canonical_path}/$<
 
 src/cfgparse.tab.c: src/cfgparse.y $(i3_HEADERS_DEP)
        echo "[i3] YACC $<"
-       $(BISON) --debug --verbose -b $(basename $< .y) -d $<
+       $(BISON) --debug --verbose -b $(basename $< .y) -d ${canonical_path}/$<
 
 # This target compiles the command parser twice:
 # Once with -DTEST_PARSER, creating a stand-alone executable used for tests,
@@ -43,7 +51,7 @@ src/cfgparse.tab.c: src/cfgparse.y $(i3_HEADERS_DEP)
 src/commands_parser.o: src/commands_parser.c $(i3_HEADERS_DEP) i3-command-parser.stamp
        echo "[i3] CC $<"
        $(CC) $(I3_CPPFLAGS) $(CPPFLAGS) $(i3_CFLAGS) $(I3_CFLAGS) $(CFLAGS) $(I3_LDFLAGS) $(LDFLAGS) -DTEST_PARSER -o test.commands_parser $< $(i3_LIBS) $(LIBS)
-       $(CC) $(I3_CPPFLAGS) $(CPPFLAGS) $(i3_CFLAGS) $(I3_CFLAGS) $(CFLAGS) -c -o $@ $<
+       $(CC) $(I3_CPPFLAGS) $(CPPFLAGS) $(i3_CFLAGS) $(I3_CFLAGS) $(CFLAGS) -c -o $@ ${canonical_path}/$<
 
 i3-command-parser.stamp: generate-command-parser.pl parser-specs/commands.spec
        echo "[i3] Generating command parser"