init_disassemble_info() signature changes causes compile failures

From: Andres Freund <andres@anarazel.de>
To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
	Quentin Monnet <quentin@isovalent.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: init_disassemble_info() signature changes causes compile failures
Date: Wed, 22 Jun 2022 11:19:18 -0700	[thread overview]
Message-ID: <20220622181918.ykrs5rsnmx3og4sv@alap3.anarazel.de> (raw)

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Hi,

binutils changed the signature of init_disassemble_info(), which now causes
perf and bpftool to fail to compile (e.g. on debian unstable).

Relevant binutils commit: https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=60a3da00bd5407f07d64dff82a4dae98230dfaac

util/annotate.c: In function ‘symbol__disassemble_bpf’:
util/annotate.c:1765:9: error: too few arguments to function ‘init_disassemble_info’
 1765 |         init_disassemble_info(&info, s,
      |         ^~~~~~~~~~~~~~~~~~~~~
In file included from util/annotate.c:1718:
/usr/include/dis-asm.h:472:13: note: declared here
  472 | extern void init_disassemble_info (struct disassemble_info *dinfo, void *stream,
      |             ^~~~~~~~~~~~~~~~~~~~~

with equivalent failures in

tools/bpf/bpf_jit_disasm.c
tools/bpf/bpftool/jit_disasm.c

The fix is easy enough, add a wrapper around fprintf() that conforms to the
new signature.

However I assume the necessary feature test and wrapper should only be added
once? I don't know the kernel stuff well enough to choose the right structure
here.

Attached is my local fix for perf. Obviously would need work to be a real
solution.

Greetings,

Andres Freund

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diff --git i/tools/perf/util/annotate.c w/tools/perf/util/annotate.c
index 82cc396ef516..b0e364d235b4 100644
--- i/tools/perf/util/annotate.c
+++ w/tools/perf/util/annotate.c
@@ -1721,6 +1721,18 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
 #include <bpf/libbpf.h>
 #include <linux/btf.h>
 
+static int fprintf_styled(void *, enum disassembler_style, const char* fmt, ...)
+{
+  va_list args;
+  int r;
+
+  va_start(args, fmt);
+  r = vprintf(fmt, args);
+  va_end(args);
+
+  return r;
+}
+
 static int symbol__disassemble_bpf(struct symbol *sym,
 				   struct annotate_args *args)
 {
@@ -1763,7 +1775,8 @@ static int symbol__disassemble_bpf(struct symbol *sym,
 		goto out;
 	}
 	init_disassemble_info(&info, s,
-			      (fprintf_ftype) fprintf);
+			      (fprintf_ftype) fprintf,
+			      fprintf_styled);
 
 	info.arch = bfd_get_arch(bfdf);
 	info.mach = bfd_get_mach(bfdf);
