[2/5] tools include: add dis-asm-compat.h to handle version differences

Origin: https://lore.kernel.org/lkml/20220703212551.1114923-3-andres@anarazel.de/

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@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Quentin Monnet <quentin@isovalent.com>
Link: http://lore.kernel.org/lkml/20220622181918.ykrs5rsnmx3og4sv@alap3.anarazel.de
Signed-off-by: Andres Freund <andres@anarazel.de>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name tools-include-add-dis-asm-compat.h-to-handle-version-differences.patch

diff --git a/tools/include/tools/dis-asm-compat.h b/tools/include/tools/dis-asm-compat.h
new file mode 100644 (file)
index 0000000..d1d003e
--- /dev/null
+++ b/tools/include/tools/dis-asm-compat.h
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _TOOLS_DIS_ASM_COMPAT_H
+#define _TOOLS_DIS_ASM_COMPAT_H
+
+#include <stdio.h>
+#include <linux/compiler.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 __maybe_unused,
+                                const char *fmt, ...)
+{
+       va_list args;
+       int r;
+
+       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 __maybe_unused)
+{
+#ifdef DISASM_INIT_STYLED
+       init_disassemble_info(info, stream,
+                             unstyled_func,
+                             styled_func);
+#else
+       init_disassemble_info(info, stream,
+                             unstyled_func);
+#endif
+}
+
+#endif /* _TOOLS_DIS_ASM_COMPAT_H */