[PATCH 3/3] perf script: Provide weak stubs for instruction decoding

[Li Guan]

When cross-compiling perf for architectures that do not yet implement
hardware-specific instruction decoding (such as RISC-V and ARM64),
the linker fails with undefined references to `dump_insn` and
`arch_is_uncond_branch` in builtin-script.c.

Provide global __weak stubs for these functions to ensure successful
linking across all architectures. Architectures that support these
features will automatically override these weak symbols.

Signed-off-by: Li Guan <guanli.oerv at isrc.iscas.ac.cn>
---
 tools/perf/builtin-script.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index c8ac9f01a3..80a8f0e80b 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -4608,3 +4608,25 @@ int cmd_script(int argc, const char **argv)
 out:
 	return err;
 }
+
+/*
+ * Provide weak stubs for architectures that have not yet implemented
+ * instruction decoding. This prevents linker errors (undefined
+ * references) on non-x86 architectures (like ARM64, RISC-V) when
+ * building perf script.
+ */
+const char * __weak dump_insn(struct perf_insn *x __maybe_unused,
+			      u64 ip __maybe_unused,
+			      u8 *inbuf __maybe_unused,
+			      int inlen __maybe_unused,
+			      int *lenp __maybe_unused)
+{
+	return NULL;
+}
+
+int __weak arch_is_uncond_branch(const unsigned char *buf __maybe_unused,
+				 size_t len __maybe_unused,
+				 int x86_64 __maybe_unused)
+{
+	return 0;
+}
-- 
2.54.0