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[PATCH 2/3] Makefile: use `find` to determine static header dependencies

From
Jeff King <peff@peff.net>
Date
Aug 22, 2014, 04:33 UTC
Message-ID
<20140822043303.GB18192@peff.net>
In-Reply-To
<20140822042716.GE27992@peff.net>

Most modern platforms will use automatically computed header dependencies to figure out when a C file needs rebuilt due to a header changing. With old compilers, however, we fallback to a static list of header files. If any of them changes, we recompile everything. This is overly conservative, but the best we can do on older platforms.

It is unfortunately easy for our static header list to grow stale, as none of the regular developers make use of it. Instead of trying to keep it up to date, let's invoke "find" to generate the list dynamically.

Since we do not use the value $(LIB_H) unless either COMPUTE_HEADER_DEPENDENCIES is turned on or the user is building "po/git.pot" (where it comes in via $(LOCALIZED_C), make is smart enough to not even run this "find" in most cases. However, we do need to stop using the "immediate" variable assignment ":=" for $(LOCALIZED_C). That's OK, because it was not otherwise useful here.

Signed-off-by: Jeff King <peff@peff.net>
---
I cannot see any reason for the ":=", but maybe I am missing something.
 Makefile | 140 ++++-----------------------------------------------------------
 1 file changed, 8 insertions(+), 132 deletions(-)
diff --git a/Makefile b/Makefile
index cf0ccdf..f2b85c9 100644
--- a/Makefile
+++ b/Makefile
@@ -432,7 +432,6 @@ XDIFF_OBJS =
 VCSSVN_OBJS =
 GENERATED_H =
 EXTRA_CPPFLAGS =
-LIB_H =
 LIB_OBJS =
 PROGRAM_OBJS =
 PROGRAMS =
@@ -631,131 +630,11 @@ VCSSVN_LIB = vcs-svn/lib.a
 
 GENERATED_H += common-cmds.h
 
-LIB_H += advice.h
-LIB_H += archive.h
-LIB_H += argv-array.h
-LIB_H += attr.h
-LIB_H += bisect.h
-LIB_H += blob.h
-LIB_H += branch.h
-LIB_H += builtin.h
-LIB_H += bulk-checkin.h
-LIB_H += bundle.h
-LIB_H += cache-tree.h
-LIB_H += cache.h
-LIB_H += color.h
-LIB_H += column.h
-LIB_H += commit.h
-LIB_H += compat/bswap.h
-LIB_H += compat/mingw.h
-LIB_H += compat/obstack.h
-LIB_H += compat/poll/poll.h
-LIB_H += compat/precompose_utf8.h
-LIB_H += compat/terminal.h
-LIB_H += compat/win32/dirent.h
-LIB_H += compat/win32/pthread.h
-LIB_H += compat/win32/syslog.h
-LIB_H += connected.h
-LIB_H += convert.h
-LIB_H += credential.h
-LIB_H += csum-file.h
-LIB_H += decorate.h
-LIB_H += delta.h
-LIB_H += diff.h
-LIB_H += diffcore.h
-LIB_H += dir.h
-LIB_H += exec_cmd.h
-LIB_H += ewah/ewok.h
-LIB_H += ewah/ewok_rlw.h
-LIB_H += fetch-pack.h
-LIB_H += fmt-merge-msg.h
-LIB_H += fsck.h
-LIB_H += gettext.h
-LIB_H += git-compat-util.h
-LIB_H += gpg-interface.h
-LIB_H += graph.h
-LIB_H += grep.h
-LIB_H += hashmap.h
-LIB_H += help.h
-LIB_H += http.h
-LIB_H += kwset.h
-LIB_H += levenshtein.h
-LIB_H += line-log.h
-LIB_H += line-range.h
-LIB_H += list-objects.h
-LIB_H += ll-merge.h
-LIB_H += log-tree.h
-LIB_H += mailmap.h
-LIB_H += merge-blobs.h
-LIB_H += merge-recursive.h
-LIB_H += mergesort.h
-LIB_H += notes-cache.h
-LIB_H += notes-merge.h
-LIB_H += notes-utils.h
-LIB_H += notes.h
-LIB_H += object.h
-LIB_H += pack-objects.h
-LIB_H += pack-revindex.h
-LIB_H += pack.h
-LIB_H += pack-bitmap.h
-LIB_H += parse-options.h
-LIB_H += patch-ids.h
-LIB_H += pathspec.h
-LIB_H += pkt-line.h
-LIB_H += prio-queue.h
-LIB_H += progress.h
-LIB_H += prompt.h
-LIB_H += quote.h
-LIB_H += reachable.h
-LIB_H += reflog-walk.h
-LIB_H += refs.h
-LIB_H += remote.h
-LIB_H += rerere.h
-LIB_H += resolve-undo.h
-LIB_H += revision.h
-LIB_H += run-command.h
-LIB_H += send-pack.h
-LIB_H += sequencer.h
-LIB_H += sha1-array.h
-LIB_H += sha1-lookup.h
-LIB_H += shortlog.h
-LIB_H += sideband.h
-LIB_H += sigchain.h
-LIB_H += strbuf.h
-LIB_H += streaming.h
-LIB_H += string-list.h
-LIB_H += submodule.h
-LIB_H += tag.h
-LIB_H += tar.h
-LIB_H += thread-utils.h
-LIB_H += transport.h
-LIB_H += tree-walk.h
-LIB_H += tree.h
-LIB_H += unpack-trees.h
-LIB_H += unicode_width.h
-LIB_H += url.h
-LIB_H += urlmatch.h
-LIB_H += userdiff.h
-LIB_H += utf8.h
-LIB_H += varint.h
-LIB_H += vcs-svn/fast_export.h
-LIB_H += vcs-svn/line_buffer.h
-LIB_H += vcs-svn/repo_tree.h
-LIB_H += vcs-svn/sliding_window.h
-LIB_H += vcs-svn/svndiff.h
-LIB_H += vcs-svn/svndump.h
-LIB_H += walker.h
-LIB_H += wildmatch.h
-LIB_H += wt-status.h
-LIB_H += xdiff-interface.h
-LIB_H += xdiff/xdiff.h
-LIB_H += xdiff/xdiffi.h
-LIB_H += xdiff/xemit.h
-LIB_H += xdiff/xinclude.h
-LIB_H += xdiff/xmacros.h
-LIB_H += xdiff/xprepare.h
-LIB_H += xdiff/xtypes.h
-LIB_H += xdiff/xutils.h
+LIB_H = $(shell $(FIND) . \
+	-name .git -prune -o \
+	-name t -prune -o \
+	-name Documentation -prune -o \
+	-name '*.h' -print)
 
 LIB_OBJS += abspath.o
 LIB_OBJS += advice.o
@@ -1381,7 +1260,6 @@ ifdef NO_INET_PTON
 endif
 ifndef NO_UNIX_SOCKETS
 	LIB_OBJS += unix-socket.o
-	LIB_H += unix-socket.h
 	PROGRAM_OBJS += credential-cache.o
 	PROGRAM_OBJS += credential-cache--daemon.o
 endif
@@ -1405,12 +1283,10 @@ endif
 ifdef BLK_SHA1
 	SHA1_HEADER = "block-sha1/sha1.h"
 	LIB_OBJS += block-sha1/sha1.o
-	LIB_H += block-sha1/sha1.h
 else
 ifdef PPC_SHA1
 	SHA1_HEADER = "ppc/sha1.h"
 	LIB_OBJS += ppc/sha1.o ppc/sha1ppc.o
-	LIB_H += ppc/sha1.h
 else
 ifdef APPLE_COMMON_CRYPTO
 	COMPAT_CFLAGS += -DCOMMON_DIGEST_FOR_OPENSSL
@@ -2128,9 +2004,9 @@ XGETTEXT_FLAGS_C = $(XGETTEXT_FLAGS) --language=C \
 XGETTEXT_FLAGS_SH = $(XGETTEXT_FLAGS) --language=Shell \
 	--keyword=gettextln --keyword=eval_gettextln
 XGETTEXT_FLAGS_PERL = $(XGETTEXT_FLAGS) --keyword=__ --language=Perl
-LOCALIZED_C := $(C_OBJ:o=c) $(LIB_H) $(GENERATED_H)
-LOCALIZED_SH := $(SCRIPT_SH)
-LOCALIZED_PERL := $(SCRIPT_PERL)
+LOCALIZED_C = $(C_OBJ:o=c) $(GENERATED_H)
+LOCALIZED_SH = $(SCRIPT_SH)
+LOCALIZED_PERL = $(SCRIPT_PERL)
 
 ifdef XGETTEXT_INCLUDE_TESTS
 LOCALIZED_C += t/t0200/test.c
-- 
2.1.0.346.ga0367b9
Previous: Jeff KingNext: Junio C Hamano
Message 9 of 27 in “Update hard-coded header dependencies”
  1. Update hard-coded header dependenciesJonathan Nieder, Aug 8, 2014
  2. Jeff KingAug 10, 2014
  3. Jeff KingAug 21, 2014
  4. 1/2 Makefile: use "find" to determine static header dependenciesJeff King, Aug 21, 2014
  5. Jonathan NiederAug 21, 2014
  6. Jeff KingAug 22, 2014
  7. 0/3 dropping manually-maintained LIB_HJeff King, Aug 22, 2014
  8. 1/3 i18n: treat "make pot" as an explicitly-invoked targetJeff King, Aug 22, 2014
  9. 2/3 Makefile: use `find` to determine static header dependenciesJeff King, Aug 22, 2014
  10. Junio C HamanoAug 25, 2014
  11. Jeff KingAug 25, 2014
  12. Jonathan NiederAug 25, 2014
  13. Jeff KingAug 25, 2014
  14. Jeff KingAug 25, 2014
  15. Jonathan NiederAug 25, 2014
  16. Junio C HamanoAug 25, 2014
  17. Jonathan NiederAug 25, 2014
  18. Junio C HamanoAug 25, 2014
  19. Jeff KingAug 26, 2014
  20. Junio C HamanoAug 26, 2014
  21. Jeff KingAug 26, 2014
  22. Junio C HamanoAug 26, 2014
  23. 3/3 Makefile: drop CHECK_HEADER_DEPENDENCIES codeJeff King, Aug 22, 2014
  24. Jiang XinAug 23, 2014
  25. 2/2 Makefile: drop CHECK_HEADER_DEPENDENCIES codeJeff King, Aug 21, 2014
  26. Junio C HamanoAug 10, 2014
  27. Junio C HamanoAug 10, 2014

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