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stack validation warning on lttng-modules bytecode interpreter

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Hi Josh,

I notice that with gcc 6.1.1, kernel 4.6, with
CONFIG_STACK_VALIDATION=y, building lttng-modules master
at commit 6c09dd94 gives this warning:

lttng-modules/lttng-filter-interpreter.o: warning: objtool: 
lttng_filter_interpret_bytecode()+0x58: sibling call from callable instruction with changed frame pointer

this object implements a bytecode interpreter using an explicit
jump table (see https://github.com/lttng/lttng-modules/blob/master/lttng-filter-interpreter.c)

If I define "INTERPRETER_USE_SWITCH" at the top of the file,
thus using the switch-case fallback implementation, the
warning vanishes.

We use an explicit jump table rather than a switch case whenever
possible for performance reasons.

I notice that tools/objtool/builtin-check.c needs to be aware of
switch-cases transformed into jump tables by the compiler. Are
explicit jump tables supported by the stack validator ? Do we
need to add annotation to our code ?

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

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stack validation warning on lttng-modules bytecode interpreter Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-06-15 19:00 +0200
  Re: stack validation warning on lttng-modules bytecode interpreter Josh Poimboeuf <jpoimboe@redhat.com> - 2016-06-15 20:20 +0200
    Re: stack validation warning on lttng-modules bytecode interpreter Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-06-15 21:20 +0200
      Re: stack validation warning on lttng-modules bytecode interpreter Josh Poimboeuf <jpoimboe@redhat.com> - 2016-06-15 21:40 +0200
        Re: stack validation warning on lttng-modules bytecode interpreter Josh Poimboeuf <jpoimboe@redhat.com> - 2016-06-15 22:30 +0200
          Re: stack validation warning on lttng-modules bytecode interpreter Josh Poimboeuf <jpoimboe@redhat.com> - 2016-06-15 22:30 +0200
            Re: stack validation warning on lttng-modules bytecode interpreter Mathieu Desnoyers <mathieu.desnoyers@efficios.com> - 2016-06-15 22:50 +0200

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