From d9ad8bc0ca823705413f75b50c442a88cc518b35 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Sun, 5 Apr 2009 16:20:02 +0200 Subject: [PATCH] branch tracer: Fix for enabling branch profiling makes sparse unusable One of the changes between kernels 2.6.28 and 2.6.29 is that a branch profiler has been added for if() statements. Unfortunately this patch makes the sparse output unusable with CONFIG_TRACE_BRANCH_PROFILING=y: when branch profiling is enabled, sparse prints so much false positives that the real issues are no longer visible. This behavior can be reproduced as follows: * enable CONFIG_TRACE_BRANCH_PROFILING, e.g. by running make allyesconfig or make allmodconfig. * run make C=2 Result: a huge number of the following sparse warnings. ... include/linux/cpumask.h:547:2: warning: symbol '______r' shadows an earlier one include/linux/cpumask.h:547:2: originally declared here ... The patch below fixes this by disabling branch profiling while analyzing the kernel code with sparse. See also: * http://lkml.org/lkml/2008/11/21/18 * http://bugzilla.kernel.org/show_bug.cgi?id=12925 Signed-off-by: Bart Van Assche Cc: Andrew Morton Cc: Steven Rostedt LKML-Reference: <200904051620.02311.bart.vanassche@gmail.com> Signed-off-by: Ingo Molnar --- include/linux/compiler.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 6faa7e549de4..8872ad6dd89b 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -76,7 +76,8 @@ struct ftrace_branch_data { * Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code * to disable branch tracing on a per file basis. */ -#if defined(CONFIG_TRACE_BRANCH_PROFILING) && !defined(DISABLE_BRANCH_PROFILING) +#if defined(CONFIG_TRACE_BRANCH_PROFILING) \ + && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__) void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); #define likely_notrace(x) __builtin_expect(!!(x), 1) -- 2.20.1