From patchwork Thu Feb 14 03:05:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 10811657 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8E0F8139A for ; Thu, 14 Feb 2019 03:06:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7BCD02C3E8 for ; Thu, 14 Feb 2019 03:06:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6F7822D813; Thu, 14 Feb 2019 03:06:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DF9882C3E8 for ; Thu, 14 Feb 2019 03:06:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403975AbfBNDGS (ORCPT ); Wed, 13 Feb 2019 22:06:18 -0500 Received: from conuserg-07.nifty.com ([210.131.2.74]:64382 "EHLO conuserg-07.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394145AbfBNDGG (ORCPT ); Wed, 13 Feb 2019 22:06:06 -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 x1E35Pg7020814; Thu, 14 Feb 2019 12:05:28 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-07.nifty.com x1E35Pg7020814 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1550113529; bh=UInuA6sjxvO1VVgZ8XgryVYJnyZUkO/SzulavMh+Za8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DD8gCOZ6YNKXjbMHKfAvzQAluld269OrZC1Z5CbLmpaYr68I6ycnzA2MYNPcmvx4c VnhWyuscYXmVr+LFbUWbBTd/pSe3RNUtVouLxokARc9aGEuNKiPb8Y+Vu4qPKtaLEn BNWrIbI/tQFwRe7m1n348IQcq/nzOMmIKucDsbJO6IfpRQVDuRh4NRyGCJEyviADWY JIr0DwsQR/JjpGDrYh8hIpdNr2iWECuIJyi2k5qvfwzZEoRIpwNfGitEU/d29WWC/a /CZxyc0ICvZiYNPrRMzSqBN7jlu9feDwCzVKYCr6ov+ZBpJG0I4PkNmzXW5ZbQFnvC xWN6j01qMFMDw== X-Nifty-SrcIP: [153.142.97.92] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: Sam Ravnborg , Masahiro Yamada , Michal Marek , linux-kernel@vger.kernel.org Subject: [PATCH 6/8] kbuild: make -r/-R effective in top Makefile for old Make versions Date: Thu, 14 Feb 2019 12:05:19 +0900 Message-Id: <1550113521-23577-6-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1550113521-23577-1-git-send-email-yamada.masahiro@socionext.com> References: <1550113521-23577-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- Makefile | 48 ++++++++++++++++++++++++++---------------------- 1 file changed, 26 insertions(+), 22 deletions(-) diff --git a/Makefile b/Makefile index 0180b23..25d7d46 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. +ifndef KBUILD_SUBMAKE + +# 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) KBUILD_SUBMAKE=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 # KBUILD_SUBMAKE # 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 @@ -1752,7 +1756,7 @@ $(cmd_files): ; # Do not try to update included dependency files endif # ifeq ($(config-targets),1) endif # ifeq ($(mixed-targets),1) -endif # skip-makefile +endif # ifndef KBUILD_SUBMAKE PHONY += FORCE FORCE: