From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29FDDC43381 for ; Fri, 22 Feb 2019 07:40:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E1DE220823 for ; Fri, 22 Feb 2019 07:40:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com header.b="qJcl0Md1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726648AbfBVHkZ (ORCPT ); Fri, 22 Feb 2019 02:40:25 -0500 Received: from conuserg-07.nifty.com ([210.131.2.74]:53325 "EHLO conuserg-07.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725821AbfBVHkW (ORCPT ); Fri, 22 Feb 2019 02:40:22 -0500 Received: from pug.e01.socionext.com (p14092-ipngnfx01kyoto.kyoto.ocn.ne.jp [153.142.97.92]) (authenticated) by conuserg-07.nifty.com with ESMTP id x1M7eEN1013122; Fri, 22 Feb 2019 16:40:15 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-07.nifty.com x1M7eEN1013122 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1550821215; bh=ShLhb3WIzeeB+W+Duw3DHWEdsX60HCOwaHOO2R3ie0k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qJcl0Md10oQcoXayGlWXNY+W8O17qfDDowqRNY21BFSSaJW1JNH/kZ4PnY+mjDwMy 6ho86dwoE6PzWBTMmChQaNCGhTuKzMOqYk0MjoOBtOTJKCkp+jsy7JzQJXSSIrZV3X p+RJj/+mqn7jnCdLUKsiTbCSxIajc/hggYCWsJltvw+NvBZxtO9buY5Q3U47RmLs9E KUtXSAm3Bmb3UVFmDn6LVtw9jtamhd0DrV/TewFR4e4jFF8TpVOCqa8zz06CpUqxSo oZt2vv+CirwZl50AIpUup0UWy+lAkkmsf/qOA8cTg1wJYJwsd/KIa4NrZOgAforUD7 qHVoAmczjamNw== X-Nifty-SrcIP: [153.142.97.92] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: Masahiro Yamada , Michal Marek , linux-kernel@vger.kernel.org Subject: [PATCH v2 2/6] kbuild: make -r/-R effective in top Makefile for old Make versions Date: Fri, 22 Feb 2019 16:40:07 +0900 Message-Id: <1550821211-30324-2-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1550821211-30324-1-git-send-email-yamada.masahiro@socionext.com> References: <1550821211-30324-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Adding -rR to MAKEFLAGS is important because we do not want to be bothered by built-in implicit rules or variables. One problem that used to exist in older GNU Make versions is MAKEFLAGS += -rR ... does not become effective in the current Makefile. When you are building with O= option, it becomes effective in the top Makefile since it recurses via 'sub-make' target. Otherwise, the top Makefile tries implicit rules. That is why we explicitly add empty rules for Makefiles, but we often miss to do that. In fact, adding -d option to older GNU Make versions shows it is trying a bunch of implicit pattern rules. Considering target file `scripts/Makefile.kcov'. Looking for an implicit rule for `scripts/Makefile.kcov'. Trying pattern rule with stem `Makefile.kcov'. Trying implicit prerequisite `scripts/Makefile.kcov.o'. Trying pattern rule with stem `Makefile.kcov'. Trying implicit prerequisite `scripts/Makefile.kcov.c'. Trying pattern rule with stem `Makefile.kcov'. Trying implicit prerequisite `scripts/Makefile.kcov.cc'. Trying pattern rule with stem `Makefile.kcov'. Trying implicit prerequisite `scripts/Makefile.kcov.C'. ... This issue was fixed by GNU Make commit 58dae243526b ("[Savannah #20501] Handle adding -r/-R to MAKEFLAGS in the makefile"). So, it is no longer a problem if you use GNU Make 4.0 or later. However, older versions are still widely used. So, I decided to patch the kernel Makefile to invoke sub-make regardless of O= option. This will allow further cleanups. Signed-off-by: Masahiro Yamada --- Changes in v2: - Rename KBUILD_SUBMAKE to sub-make-done Makefile | 48 ++++++++++++++++++++++++++---------------------- 1 file changed, 26 insertions(+), 22 deletions(-) diff --git a/Makefile b/Makefile index 82091b8..f0bc078 100644 --- a/Makefile +++ b/Makefile @@ -15,19 +15,6 @@ NAME = Shy Crocodile PHONY := _all _all: -# Do not use make's built-in rules and variables -# (this increases performance and avoids hard-to-debug behaviour) -MAKEFLAGS += -rR - -# Avoid funny character set dependencies -unexport LC_ALL -LC_COLLATE=C -LC_NUMERIC=C -export LC_COLLATE LC_NUMERIC - -# Avoid interference with shell env settings -unexport GREP_OPTIONS - # We are using a recursive build, so we need to do a little thinking # to get the ordering right. # @@ -44,6 +31,21 @@ unexport GREP_OPTIONS # descending is started. They are now explicitly listed as the # prepare rule. +ifneq ($(sub-make-done),1) + +# Do not use make's built-in rules and variables +# (this increases performance and avoids hard-to-debug behaviour) +MAKEFLAGS += -rR + +# Avoid funny character set dependencies +unexport LC_ALL +LC_COLLATE=C +LC_NUMERIC=C +export LC_COLLATE LC_NUMERIC + +# Avoid interference with shell env settings +unexport GREP_OPTIONS + # Beautify output # --------------------------------------------------------------------------- # @@ -111,7 +113,6 @@ export quiet Q KBUILD_VERBOSE # KBUILD_SRC is not intended to be used by the regular user (for now), # it is set on invocation of make with KBUILD_OUTPUT or O= specified. -ifeq ($(KBUILD_SRC),) # OK, Make called in directory where kernel src resides # Do we want to locate output files in a separate directory? @@ -141,6 +142,13 @@ $(if $(KBUILD_OUTPUT),, \ # 'sub-make' below. MAKEFLAGS += --include-dir=$(CURDIR) +else + +# Do not print "Entering directory ..." at all for in-tree build. +MAKEFLAGS += --no-print-directory + +endif # ifneq ($(KBUILD_OUTPUT),) + PHONY += $(MAKECMDGOALS) sub-make $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make @@ -148,16 +156,12 @@ $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make # Invoke a second make in the output directory, passing relevant variables sub-make: - $(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \ + $(Q)$(MAKE) sub-make-done=1 \ + $(if $(KBUILD_OUTPUT),-C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR)) \ -f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS)) -# Leave processing to above invocation of make -skip-makefile := 1 -endif # ifneq ($(KBUILD_OUTPUT),) -endif # ifeq ($(KBUILD_SRC),) - +else # sub-make-done # We process the rest of the Makefile if this is the final invocation of make -ifeq ($(skip-makefile),) # Do not print "Entering directory ...", # but we want to display it when entering to the output directory @@ -1766,7 +1770,7 @@ $(cmd_files): ; # Do not try to update included dependency files endif # ifeq ($(config-targets),1) endif # ifeq ($(mixed-targets),1) -endif # skip-makefile +endif # sub-make-done PHONY += FORCE FORCE: -- 2.7.4