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selftests: bpf: Support dynamic linking LLVM if static not available

Message ID 872b64e93de9a6cd6a7a10e6a5c5e7893704f743.1738276344.git.dxu@dxuuu.xyz (mailing list archive)
State New
Headers show
Series selftests: bpf: Support dynamic linking LLVM if static not available | expand

Commit Message

Daniel Xu Jan. 30, 2025, 10:33 p.m. UTC
Since 67ab80a01886 ("selftests/bpf: Prefer static linking for LLVM
libraries"), only statically linking test_progs is supported. However,
some distros only provide a dynamically linkable LLVM.

This commit adds a fallback for dynamically linking LLVM if static
linking is not available. If both options are available, static linking
is chosen.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
---
 tools/testing/selftests/bpf/Makefile | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

Comments

Eduard Zingerman Jan. 31, 2025, 12:48 a.m. UTC | #1
On Thu, 2025-01-30 at 15:33 -0700, Daniel Xu wrote:
> Since 67ab80a01886 ("selftests/bpf: Prefer static linking for LLVM
> libraries"), only statically linking test_progs is supported. However,
> some distros only provide a dynamically linkable LLVM.
> 
> This commit adds a fallback for dynamically linking LLVM if static
> linking is not available. If both options are available, static linking
> is chosen.
> 
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> ---

Tested in two configuration:
- when both static and dynamic libraries are available
  (linked against static);
- when only static libraries are available.

Tested-by: Eduard Zingerman <eddyz87@gmail.com>

[...]
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 6722080b2107..da514030a153 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -184,9 +184,14 @@  ifeq ($(feature-llvm),1)
   LLVM_CONFIG_LIB_COMPONENTS := mcdisassembler all-targets
   # both llvm-config and lib.mk add -D_GNU_SOURCE, which ends up as conflict
   LLVM_CFLAGS  += $(filter-out -D_GNU_SOURCE,$(shell $(LLVM_CONFIG) --cflags))
-  LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS))
-  LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS))
-  LLVM_LDLIBS  += -lstdc++
+  # Prefer linking statically if it's available, otherwise fallback to shared
+  ifeq ($(shell $(LLVM_CONFIG) --link-static --libs &> /dev/null && echo static),static)
+    LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-static --libs $(LLVM_CONFIG_LIB_COMPONENTS))
+    LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-static --system-libs $(LLVM_CONFIG_LIB_COMPONENTS))
+    LLVM_LDLIBS  += -lstdc++
+  else
+    LLVM_LDLIBS  += $(shell $(LLVM_CONFIG) --link-shared --libs $(LLVM_CONFIG_LIB_COMPONENTS))
+  endif
   LLVM_LDFLAGS += $(shell $(LLVM_CONFIG) --ldflags)
 endif