branch tracer: Fix for enabling branch profiling makes sparse unusable

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 <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Steven Rostedt <[email protected]>
LKML-Reference: <200904051620[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>