[PATCH v3 3/8] tools include: add dis-asm-compat.h to handle version differences

[Andres Freund]

binutils changed the signature of init_disassemble_info(), which now causes
compilation failures for tools/{perf,bpf}, e.g. on debian unstable.
Relevant binutils commit:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=60a3da00bd5407f07

This commit introduces a wrapper for init_disassemble_info(), to avoid
spreading #ifdef DISASM_INIT_STYLED to a bunch of places. Subsequent
commits will use it to fix the build failures.

It likely is worth adding a wrapper for disassember(), to avoid the already
existing DISASM_FOUR_ARGS_SIGNATURE ifdefery.

Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Cc: Quentin Monnet <quentin@xxxxxxxxxxxxx>
Cc: Ben Hutchings <benh@xxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20220622181918.ykrs5rsnmx3og4sv@xxxxxxxxxxxxxxxxx
Signed-off-by: Andres Freund <andres@xxxxxxxxxxx>
Signed-off-by: Ben Hutchings <benh@xxxxxxxxxx>
---
 tools/include/tools/dis-asm-compat.h | 55 ++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 tools/include/tools/dis-asm-compat.h

diff --git a/tools/include/tools/dis-asm-compat.h b/tools/include/tools/dis-asm-compat.h
new file mode 100644
index 000000000000..70f331e23ed3
--- /dev/null
+++ b/tools/include/tools/dis-asm-compat.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
+#ifndef _TOOLS_DIS_ASM_COMPAT_H
+#define _TOOLS_DIS_ASM_COMPAT_H
+
+#include <stdio.h>
+#include <dis-asm.h>
+
+/* define types for older binutils version, to centralize ifdef'ery a bit */
+#ifndef DISASM_INIT_STYLED
+enum disassembler_style {DISASSEMBLER_STYLE_NOT_EMPTY};
+typedef int (*fprintf_styled_ftype) (void *, enum disassembler_style, const char*, ...);
+#endif
+
+/*
+ * Trivial fprintf wrapper to be used as the fprintf_styled_func argument to
+ * init_disassemble_info_compat() when normal fprintf suffices.
+ */
+static inline int fprintf_styled(void *out,
+				 enum disassembler_style style,
+				 const char *fmt, ...)
+{
+	va_list args;
+	int r;
+
+	(void)style;
+
+	va_start(args, fmt);
+	r = vfprintf(out, fmt, args);
+	va_end(args);
+
+	return r;
+}
+
+/*
+ * Wrapper for init_disassemble_info() that hides version
+ * differences. Depending on binutils version and architecture either
+ * fprintf_func or fprintf_styled_func will be called.
+ */
+static inline void init_disassemble_info_compat(struct disassemble_info *info,
+						void *stream,
+						fprintf_ftype unstyled_func,
+						fprintf_styled_ftype styled_func)
+{
+#ifdef DISASM_INIT_STYLED
+	init_disassemble_info(info, stream,
+			      unstyled_func,
+			      styled_func);
+#else
+	(void)styled_func;
+	init_disassemble_info(info, stream,
+			      unstyled_func);
+#endif
+}
+
+#endif /* _TOOLS_DIS_ASM_COMPAT_H */
-- 
2.37.0.3.g30cc8d0f14