[PATCH v3 8/9] perf build: Support build with clang

Leo Yan
2025-10-06T16:22:02Z

Add support for building perf with clang. For cross compilation, the
Makefile dynamically selects target flag for corresponding arch.

This patch has been verified on x86_64 machine with Ubuntu distro, it
can build successfully for native target, and for cross building Arm64
and s390.

Example: native build on x86_64 / Ubuntu machine:

$ HOSTCC=clang CC=clang CXX=clang++ make -C tools/perf

Example: cross building s390 target on x86_64 / Ubuntu machine:

# Install x390x cross toolchain and headers
$ sudo apt-get install gcc-s390x-linux-gnu g++-s390x-linux-gnu \
libc6-dev-s390x-cross linux-libc-dev-s390x-cross

# Build with clang
$ HOSTCC=clang CC=clang CXX=clang++ \
ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- \
make -C tools/perf NO_LIBELF=1 NO_LIBTRACEEVENT=1 NO_LIBPYTHON=1

Signed-off-by: Leo Yan <leo.yan@arm.com>
---
tools/perf/Makefile.config | 33 ++++++++++++++++++++++++++++++++-
1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 5a5832ee7b53c604ec0d90c5ca7e2bee5bfa6a17..616e71b3d897493a2b14612cdcf4a872e2296f4d 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -23,8 +23,39 @@ HOSTCFLAGS := $(filter-out -Wnested-externs,$(EXTRA_WARNINGS))
# borrowed from kernel headers depends on it, e.g. put_unaligned_*().
CFLAGS += -fno-strict-aliasing

-# Enabled Wthread-safety analysis for clang builds.
+# Set target flag and options when using clang as compiler.
ifeq ($(CC_NO_CLANG), 0)
+ CLANG_TARGET_FLAGS_arm := arm-linux-gnueabi
+ CLANG_TARGET_FLAGS_arm64 := aarch64-linux-gnu
+ CLANG_TARGET_FLAGS_m68k := m68k-linux-gnu
+ CLANG_TARGET_FLAGS_mips := mipsel-linux-gnu
+ CLANG_TARGET_FLAGS_powerpc := powerpc64le-linux-gnu
+ CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu
+ CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu
+ CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu
+ CLANG_TARGET_FLAGS_x86_64 := x86_64-linux-gnu
+
+ # Default to host architecture if ARCH is not explicitly given.
+ ifeq ($(ARCH), $(HOSTARCH))
+ CLANG_TARGET_FLAGS := $(shell $(CLANG) -print-target-triple)
+ else
+ CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(ARCH))
+ endif
+
+ ifeq ($(CROSS_COMPILE),)
+ ifeq ($(CLANG_TARGET_FLAGS),)
+ $(error Specify CROSS_COMPILE or add CLANG_TARGET_FLAGS for $(ARCH))
+ else
+ CLANG_FLAGS += --target=$(CLANG_TARGET_FLAGS)
+ endif # CLANG_TARGET_FLAGS
+ else
+ CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
+ endif # CROSS_COMPILE
+
+ CC := $(CLANG) $(CLANG_FLAGS) -fintegrated-as
+ CXX := $(CXX) $(CLANG_FLAGS) -fintegrated-as
+
+ # Enabled Wthread-safety analysis for clang builds.
CFLAGS += -Wthread-safety
endif

--
2.34.1