From ad592bbbbdb78cafac28b789600b7fdd86adbb91 Mon Sep 17 00:00:00 2001 From: "siggi@chromium.org" Date: Thu, 1 Mar 2012 01:01:05 +0000 Subject: Support the Syzygy instrumenting profiler. This change depends on a new API in V8 to support return-address rewriting profilers, landed at http://code.google.com/p/v8/source/detail?r=10845. BUG=None TEST=None Review URL: http://codereview.chromium.org/9477002 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@124319 0039d316-1c4b-4281-b951-d872f2087c98 --- base/debug/profiler.h | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) (limited to 'base/debug/profiler.h') diff --git a/base/debug/profiler.h b/base/debug/profiler.h index 69795a5..d880324 100644 --- a/base/debug/profiler.h +++ b/base/debug/profiler.h @@ -1,4 +1,4 @@ -// Copyright (c) 2011 The Chromium Authors. All rights reserved. +// Copyright (c) 2012 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. @@ -9,6 +9,7 @@ #include #include "base/base_export.h" +#include "base/basictypes.h" // The Profiler functions allow usage of the underlying sampling based // profiler. If the application has not been built with the necessary @@ -34,6 +35,33 @@ BASE_EXPORT bool BeingProfiled(); // Reset profiling after a fork, which disables timers. BASE_EXPORT void RestartProfilingAfterFork(); +// Returns true iff this executable is instrumented with the Syzygy profiler. +BASE_EXPORT bool IsBinaryInstrumented(); + +// There's a class of profilers that use "return address swizzling" to get a +// hook on function exits. This class of profilers uses some form of entry hook, +// like e.g. binary instrumentation, or a compiler flag, that calls a hook each +// time a function is invoked. The hook then switches the return address on the +// stack for the address of an exit hook function, and pushes the original +// return address to a shadow stack of some type. When in due course the CPU +// executes a return to the exit hook, the exit hook will do whatever work it +// does on function exit, then arrange to return to the original return address. +// This class of profiler does not play well with programs that look at the +// return address, as does e.g. V8. V8 uses the return address to certain +// runtime functions to find the JIT code that called it, and from there finds +// the V8 data structures associated to the JS function involved. +// A return address resolution function is used to fix this. It allows such +// programs to resolve a location on stack where a return address originally +// resided, to the shadow stack location where the profiler stashed it. +typedef uintptr_t (*ReturnAddressLocationResolver)( + uintptr_t return_addr_location); + +// If this binary is instrumented and the instrumentation supplies a return +// address resolution function, finds and returns the address resolution +// function. Otherwise returns NULL. +BASE_EXPORT ReturnAddressLocationResolver + GetProfilerReturnAddrResolutionFunc(); + } // namespace debug } // namespace base -- cgit v1.1