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https://github.com/torvalds/linux
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a278f3d819
The '&&' command seems to have a bad effect when $(cmd_$(1)) exits with
non-zero effect: the command failure is masked (despite `set -e`) and all but
the first command of $(dep-cmd) is executed (successfully, as they are mostly
printfs), thus overall returning 0 in the end.
This means in practice that despite compilation errors, tools's build Makefile
will return success. We see this very reliably with libbpf's Makefile, which
doesn't get compilation error propagated properly. This in turns causes issues
with selftests build, as well as bpftool and other projects that rely on
building libbpf.
The fix is simple: don't use &&. Given `set -e`, we don't need to chain
commands with &&. The shell will exit on first failure, giving desired
behavior and propagating error properly.
Fixes: 275e2d9559 ("tools build: Move dependency copy into function")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/bpf/20200731024244.872574-1-andriin@fb.com
102 lines
4.1 KiB
Text
102 lines
4.1 KiB
Text
###
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# build: Generic definitions
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#
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# Lots of this code have been borrowed or heavily inspired from parts
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# of kbuild code, which is not credited, but mostly developed by:
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#
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# Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015
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# Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015
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#
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###
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# Convenient variables
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comma := ,
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squote := '
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pound := \#
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###
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# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
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dot-target = $(dir $@).$(notdir $@)
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###
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# filename of target with directory and extension stripped
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basetarget = $(basename $(notdir $@))
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###
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# The temporary file to save gcc -MD generated dependencies must not
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# contain a comma
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depfile = $(subst $(comma),_,$(dot-target).d)
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###
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# Check if both arguments has same arguments. Result is empty string if equal.
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arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
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$(filter-out $(cmd_$@), $(cmd_$(1))) )
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###
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# Escape single quote for use in echo statements
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escsq = $(subst $(squote),'\$(squote)',$1)
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# Echo command
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# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
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echo-cmd = $(if $($(quiet)cmd_$(1)),\
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echo ' $(call escsq,$($(quiet)cmd_$(1)))';)
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###
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# Replace >$< with >$$< to preserve $ when reloading the .cmd file
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# (needed for make)
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# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
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# (needed for make)
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# Replace >'< with >'\''< to be able to enclose the whole string in '...'
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# (needed for the shell)
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make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
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###
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# Find any prerequisites that is newer than target or that does not exist.
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# PHONY targets skipped in both cases.
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any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
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###
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# Copy dependency data into .cmd file
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# - gcc -M dependency info
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# - command line to create object 'cmd_object :='
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dep-cmd = $(if $(wildcard $(fixdep)), \
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$(fixdep) $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp; \
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rm -f $(depfile); \
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mv -f $(dot-target).tmp $(dot-target).cmd, \
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printf '$(pound) cannot find fixdep (%s)\n' $(fixdep) > $(dot-target).cmd; \
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printf '$(pound) using basic dep data\n\n' >> $(dot-target).cmd; \
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cat $(depfile) >> $(dot-target).cmd; \
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printf '\n%s\n' 'cmd_$@ := $(make-cmd)' >> $(dot-target).cmd)
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###
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# if_changed_dep - execute command if any prerequisite is newer than
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# target, or command line has changed and update
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# dependencies in the cmd file
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if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)), \
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@set -e; \
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$(echo-cmd) $(cmd_$(1)); \
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$(dep-cmd))
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# if_changed - execute command if any prerequisite is newer than
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# target, or command line has changed
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if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
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@set -e; \
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$(echo-cmd) $(cmd_$(1)); \
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printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
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###
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# C flags to be used in rule definitions, includes:
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# - depfile generation
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# - global $(CFLAGS)
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# - per target C flags
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# - per object C flags
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# - BUILD_STR macro to allow '-D"$(variable)"' constructs
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c_flags_1 = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
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c_flags_2 = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(c_flags_1))
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c_flags = $(filter-out $(CFLAGS_REMOVE_$(obj)), $(c_flags_2))
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cxx_flags = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(CXXFLAGS) -D"BUILD_STR(s)=\#s" $(CXXFLAGS_$(basetarget).o) $(CXXFLAGS_$(obj))
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###
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## HOSTCC C flags
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host_c_flags = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(KBUILD_HOSTCFLAGS) -D"BUILD_STR(s)=\#s" $(HOSTCFLAGS_$(basetarget).o) $(HOSTCFLAGS_$(obj))
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