While separate features have been defined to determine which linking flags are required to use libbfd depending on the distribution (libbfd, libbfd-liberty and libbfd-liberty-z), the same has not been done for other features requiring linking to libbfd. For example, disassembler-four-args requires linking to libbfd too, but it should use the right linking flags. If not all the required ones are specified, e.g. -liberty, detection will always fail even if the feature is available. Instead of creating new features, similarly to libbfd, simply retry detection with the different set of flags until detection succeeds (or fails, if the libraries are missing). In this way, feature detection is transparent for the users of this building mechanism (e.g. perf), and those users don't have for example to set an appropriate value for the FEATURE_CHECK_LDFLAGS-disassembler-four-args variable. The number of retries and features for which the retry mechanism is implemented is low enough to make the increase in the complexity of Makefile negligible. Tested with perf and bpftool on Ubuntu 20.04.4 LTS, Fedora 36 and openSUSE Tumbleweed. Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx> --- tools/build/feature/Makefile | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile index 7c2a17e23c30..063dab19148c 100644 --- a/tools/build/feature/Makefile +++ b/tools/build/feature/Makefile @@ -89,6 +89,8 @@ all: $(FILES) __BUILD = $(CC) $(CFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS) BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1 + BUILD_BFD = $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl + BUILD_ALL = $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd -lcap __BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS) BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1 @@ -96,7 +98,7 @@ __BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$( ############################### $(OUTPUT)test-all.bin: - $(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -lslang $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma -lzstd -lcap + $(BUILD_ALL) || $(BUILD_ALL) -lopcodes -liberty $(OUTPUT)test-hello.bin: $(BUILD) @@ -240,13 +242,14 @@ $(OUTPUT)test-libpython.bin: $(BUILD) $(FLAGS_PYTHON_EMBED) $(OUTPUT)test-libbfd.bin: - $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl + $(BUILD_BFD) $(OUTPUT)test-libbfd-buildid.bin: - $(BUILD) -DPACKAGE='"perf"' -lbfd -ldl + $(BUILD_BFD) || $(BUILD_BFD) -liberty || $(BUILD_BFD) -liberty -lz $(OUTPUT)test-disassembler-four-args.bin: - $(BUILD) -DPACKAGE='"perf"' -lbfd -lopcodes + $(BUILD_BFD) -lopcodes || $(BUILD_BFD) -lopcodes -liberty || \ + $(BUILD_BFD) -lopcodes -liberty -lz $(OUTPUT)test-reallocarray.bin: $(BUILD) -- 2.25.1
