Commit 5fc10e76 authored by Masahiro Yamada's avatar Masahiro Yamada

kbuild: revive "Entering directory" for Make >= 4.4.1

With commit 9da0763b ("kbuild: Use relative path when building in
a subdir of the source tree"), compiler messages in out-of-tree builds
include relative paths, which are relative to the build directory, not
the directory where make was started.

To help IDEs/editors find the source files, Kbuild lets GNU Make print
"Entering directory ..." when it changes the working directory. It has
been working fine for a long time, but David reported it is broken with
the latest GNU Make.

The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537]
Fix setting -w in makefiles"). Previously, setting --no-print-directory
to MAKEFLAGS only affected child makes, but it is now interpreted in
the current make as soon as it is set.

[test code]

  $ cat /tmp/Makefile
  ifneq ($(SUBMAKE),1)
  MAKEFLAGS += --no-print-directory
  all: ; $(MAKE) SUBMAKE=1
  else
  all: ; :
  endif

[before 8f9e7722ff0f]

  $ make -C /tmp
  make: Entering directory '/tmp'
  make SUBMAKE=1
  :
  make: Leaving directory '/tmp'

[after 8f9e7722ff0f]

  $ make -C /tmp
  make SUBMAKE=1
  :

Previously, the effect of --no-print-directory was delayed until Kbuild
started the directory descending, but it is no longer true with GNU Make
4.4.1.

This commit adds one more recursion to cater to GNU Make >= 4.4.1.

When Kbuild needs to change the working directory, __submake will be
executed twice.

  __submake without --no-print-directory  --> show "Entering directory ..."
  __submake with    --no-print-directory  --> parse the rest of Makefile

We end up with one more recursion than needed for GNU Make < 4.4.1, but
I do not want to complicate the version check.
Reported-by: default avatarDavid Howells <dhowells@redhat.com>
Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
Tested-by: default avatarNicolas Schier <n.schier@avm.de>
parent 5fa94ceb
......@@ -191,13 +191,6 @@ $(if $(abs_objtree),, \
abs_objtree := $(realpath $(abs_objtree))
endif # ifneq ($(KBUILD_OUTPUT),)
ifeq ($(abs_objtree),$(CURDIR))
# Suppress "Entering directory ..." unless we are changing the work directory.
MAKEFLAGS += --no-print-directory
else
need-sub-make := 1
endif
ifneq ($(words $(subst :, ,$(abs_srctree))), 1)
$(error source directory cannot contain spaces or colons)
endif
......@@ -212,6 +205,23 @@ endif
export sub_make_done := 1
endif # sub_make_done
ifeq ($(abs_objtree),$(CURDIR))
# Suppress "Entering directory ..." if we are at the final work directory.
no-print-directory := --no-print-directory
else
# Recursion to show "Entering directory ..."
need-sub-make := 1
endif
ifeq ($(filter --no-print-directory, $(MAKEFLAGS)),)
# If --no-print-directory is unset, recurse once again to set it.
# You may end up recursing into __sub-make twice. This is needed due to the
# behavior change in GNU Make 4.4.1.
need-sub-make := 1
endif
ifeq ($(need-sub-make),1)
PHONY += $(MAKECMDGOALS) __sub-make
......@@ -221,18 +231,12 @@ $(filter-out $(this-makefile), $(MAKECMDGOALS)) __all: __sub-make
# Invoke a second make in the output directory, passing relevant variables
__sub-make:
$(Q)$(MAKE) -C $(abs_objtree) -f $(abs_srctree)/Makefile $(MAKECMDGOALS)
$(Q)$(MAKE) $(no-print-directory) -C $(abs_objtree) \
-f $(abs_srctree)/Makefile $(MAKECMDGOALS)
endif # need-sub-make
endif # sub_make_done
else # need-sub-make
# We process the rest of the Makefile if this is the final invocation of make
ifeq ($(need-sub-make),)
# Do not print "Entering directory ...",
# but we want to display it when entering to the output directory
# so that IDEs/editors are able to understand relative filenames.
MAKEFLAGS += --no-print-directory
ifeq ($(abs_srctree),$(abs_objtree))
# building in the source tree
......
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