linux_dsm_epyc7002/tools/build/Makefile.feature
Thomas Hebb e3232c2f39 tools build feature: Use CC and CXX from parent
commit c8c188679c ("tools build: Use the same CC for feature detection
and actual build") changed these assignments from unconditional (:=) to
conditional (?=) so that they wouldn't clobber values from the
environment. However, conditional assignment does not work properly for
variables that Make implicitly sets, among which are CC and CXX. To
quote tools/scripts/Makefile.include, which handles this properly:

  # Makefiles suck: This macro sets a default value of $(2) for the
  # variable named by $(1), unless the variable has been set by
  # environment or command line. This is necessary for CC and AR
  # because make sets default values, so the simpler ?= approach
  # won't work as expected.

In other words, the conditional assignments will not run even if the
variables are not overridden in the environment; Make will set CC to
"cc" and CXX to "g++" when it starts[1], meaning the variables are not
empty by the time the conditional assignments are evaluated. This breaks
cross-compilation when CROSS_COMPILE is set but CC isn't, since "cc"
gets used for feature detection instead of the cross compiler (and
likewise for CXX).

To fix the issue, just pass down the values of CC and CXX computed by
the parent Makefile, which gets included by the Makefile that actually
builds whatever we're detecting features for and so is guaranteed to
have good values. This is a better solution anyway, since it means we
aren't trying to replicate the logic of the parent build system and so
don't risk it getting out of sync.

Leave PKG_CONFIG alone, since 1) there's no common logic to compute it
in Makefile.include, and 2) it's not an implicit variable, so
conditional assignment works properly.

[1] https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html

Fixes: c8c188679c ("tools build: Use the same CC for feature detection and actual build")
Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: thomas hebb <tommyhebb@gmail.com>
Link: http://lore.kernel.org/lkml/0a6e69d1736b0fa231a648f50b0cce5d8a6734ef.1595822871.git.tommyhebb@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-07-31 09:27:58 -03:00

253 lines
8.2 KiB
Gherkin

# SPDX-License-Identifier: GPL-2.0-only
feature_dir := $(srctree)/tools/build/feature
ifneq ($(OUTPUT),)
OUTPUT_FEATURES = $(OUTPUT)feature/
$(shell mkdir -p $(OUTPUT_FEATURES))
endif
feature_check = $(eval $(feature_check_code))
define feature_check_code
feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CC=$(CC) CXX=$(CXX) CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
endef
feature_set = $(eval $(feature_set_code))
define feature_set_code
feature-$(1) := 1
endef
#
# Build the feature check binaries in parallel, ignore errors, ignore return value and suppress output:
#
#
# Note that this is not a complete list of all feature tests, just
# those that are typically built on a fully configured system.
#
# [ Feature tests not mentioned here have to be built explicitly in
# the rule that uses them - an example for that is the 'bionic'
# feature check. ]
#
FEATURE_TESTS_BASIC := \
backtrace \
dwarf \
dwarf_getlocations \
eventfd \
fortify-source \
sync-compare-and-swap \
get_current_dir_name \
gettid \
glibc \
gtk2 \
gtk2-infobar \
libbfd \
libcap \
libelf \
libelf-getphdrnum \
libelf-gelf_getnote \
libelf-getshdrstrndx \
libelf-mmap \
libnuma \
numa_num_possible_cpus \
libperl \
libpython \
libpython-version \
libslang \
libslang-include-subdir \
libcrypto \
libunwind \
pthread-attr-setaffinity-np \
pthread-barrier \
reallocarray \
stackprotector-all \
timerfd \
libdw-dwarf-unwind \
zlib \
lzma \
get_cpuid \
bpf \
sched_getcpu \
sdt \
setns \
libaio \
libzstd \
disassembler-four-args \
file-handle
# FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list
# of all feature tests
FEATURE_TESTS_EXTRA := \
bionic \
compile-32 \
compile-x32 \
cplus-demangle \
hello \
libbabeltrace \
libbfd-liberty \
libbfd-liberty-z \
libopencsd \
libunwind-x86 \
libunwind-x86_64 \
libunwind-arm \
libunwind-aarch64 \
libunwind-debug-frame \
libunwind-debug-frame-arm \
libunwind-debug-frame-aarch64 \
cxx \
llvm \
llvm-version \
clang \
libbpf \
libpfm4
FEATURE_TESTS ?= $(FEATURE_TESTS_BASIC)
ifeq ($(FEATURE_TESTS),all)
FEATURE_TESTS := $(FEATURE_TESTS_BASIC) $(FEATURE_TESTS_EXTRA)
endif
FEATURE_DISPLAY ?= \
dwarf \
dwarf_getlocations \
glibc \
gtk2 \
libbfd \
libcap \
libelf \
libnuma \
numa_num_possible_cpus \
libperl \
libpython \
libcrypto \
libunwind \
libdw-dwarf-unwind \
zlib \
lzma \
get_cpuid \
bpf \
libaio \
libzstd \
disassembler-four-args
# Set FEATURE_CHECK_(C|LD)FLAGS-all for all FEATURE_TESTS features.
# If in the future we need per-feature checks/flags for features not
# mentioned in this list we need to refactor this ;-).
set_test_all_flags = $(eval $(set_test_all_flags_code))
define set_test_all_flags_code
FEATURE_CHECK_CFLAGS-all += $(FEATURE_CHECK_CFLAGS-$(1))
FEATURE_CHECK_LDFLAGS-all += $(FEATURE_CHECK_LDFLAGS-$(1))
endef
$(foreach feat,$(FEATURE_TESTS),$(call set_test_all_flags,$(feat)))
#
# Special fast-path for the 'all features are available' case:
#
$(call feature_check,all,$(MSG))
#
# Just in case the build freshly failed, make sure we print the
# feature matrix:
#
ifeq ($(feature-all), 1)
#
# test-all.c passed - just set all the core feature flags to 1:
#
$(foreach feat,$(FEATURE_TESTS),$(call feature_set,$(feat)))
#
# test-all.c does not comprise these tests, so we need to
# for this case to get features proper values
#
$(call feature_check,compile-32)
$(call feature_check,compile-x32)
$(call feature_check,bionic)
$(call feature_check,libbabeltrace)
else
$(foreach feat,$(FEATURE_TESTS),$(call feature_check,$(feat)))
endif
#
# Print the result of the feature test:
#
feature_print_status = $(eval $(feature_print_status_code)) $(info $(MSG))
define feature_print_status_code
ifeq ($(feature-$(1)), 1)
MSG = $(shell printf '...%30s: [ \033[32mon\033[m ]' $(1))
else
MSG = $(shell printf '...%30s: [ \033[31mOFF\033[m ]' $(1))
endif
endef
feature_print_text = $(eval $(feature_print_text_code)) $(info $(MSG))
define feature_print_text_code
MSG = $(shell printf '...%30s: %s' $(1) $(2))
endef
#
# generates feature value assignment for name, like:
# $(call feature_assign,dwarf) == feature-dwarf=1
#
feature_assign = feature-$(1)=$(feature-$(1))
FEATURE_DUMP_FILENAME = $(OUTPUT)FEATURE-DUMP$(FEATURE_USER)
FEATURE_DUMP := $(shell touch $(FEATURE_DUMP_FILENAME); cat $(FEATURE_DUMP_FILENAME))
feature_dump_check = $(eval $(feature_dump_check_code))
define feature_dump_check_code
ifeq ($(findstring $(1),$(FEATURE_DUMP)),)
$(2) := 1
endif
endef
#
# First check if any test from FEATURE_DISPLAY
# and set feature_display := 1 if it does
$(foreach feat,$(FEATURE_DISPLAY),$(call feature_dump_check,$(call feature_assign,$(feat)),feature_display))
#
# Now also check if any other test changed,
# so we force FEATURE-DUMP generation
$(foreach feat,$(FEATURE_TESTS),$(call feature_dump_check,$(call feature_assign,$(feat)),feature_dump_changed))
# The $(feature_display) controls the default detection message
# output. It's set if:
# - detected features differes from stored features from
# last build (in $(FEATURE_DUMP_FILENAME) file)
# - one of the $(FEATURE_DISPLAY) is not detected
# - VF is enabled
ifeq ($(feature_dump_changed),1)
$(shell rm -f $(FEATURE_DUMP_FILENAME))
$(foreach feat,$(FEATURE_TESTS),$(shell echo "$(call feature_assign,$(feat))" >> $(FEATURE_DUMP_FILENAME)))
endif
feature_display_check = $(eval $(feature_check_display_code))
define feature_check_display_code
ifneq ($(feature-$(1)), 1)
feature_display := 1
endif
endef
$(foreach feat,$(FEATURE_DISPLAY),$(call feature_display_check,$(feat)))
ifeq ($(VF),1)
feature_display := 1
feature_verbose := 1
endif
ifeq ($(feature_display),1)
$(info )
$(info Auto-detecting system features:)
$(foreach feat,$(FEATURE_DISPLAY),$(call feature_print_status,$(feat),))
ifneq ($(feature_verbose),1)
$(info )
endif
endif
ifeq ($(feature_verbose),1)
TMP := $(filter-out $(FEATURE_DISPLAY),$(FEATURE_TESTS))
$(foreach feat,$(TMP),$(call feature_print_status,$(feat),))
$(info )
endif