45 lines
1.9 KiB
C
45 lines
1.9 KiB
C
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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_DEBUG_ALIAS_H_
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#define BASE_DEBUG_ALIAS_H_
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#include "base/base_export.h"
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#include "base/stl_util.h"
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#include "base/strings/string_util.h"
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namespace base {
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namespace debug {
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// Make the optimizer think that var is aliased. This is to prevent it from
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// optimizing out local variables that would not otherwise be live at the point
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// of a potential crash.
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// base::debug::Alias should only be used for local variables, not globals,
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// object members, or function return values - these must be copied to locals if
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// you want to ensure they are recorded in crash dumps.
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// Note that if the local variable is a pointer then its value will be retained
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// but the memory that it points to will probably not be saved in the crash
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// dump - by default only stack memory is saved. Therefore the aliasing
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// technique is usually only worthwhile with non-pointer variables. If you have
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// a pointer to an object and you want to retain the object's state you need to
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// copy the object or its fields to local variables. Example usage:
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// int last_error = err_;
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// base::debug::Alias(&last_error);
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// DEBUG_ALIAS_FOR_CSTR(name_copy, p->name, 16);
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// CHECK(false);
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void BASE_EXPORT Alias(const void* var);
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} // namespace debug
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} // namespace base
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// Convenience macro that copies the null-terminated string from |c_str| into a
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// stack-allocated char array named |var_name| that holds up to |char_count|
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// characters and should be preserved in memory dumps.
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#define DEBUG_ALIAS_FOR_CSTR(var_name, c_str, char_count) \
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char var_name[char_count]; \
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::base::strlcpy(var_name, (c_str), base::size(var_name)); \
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::base::debug::Alias(var_name);
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#endif // BASE_DEBUG_ALIAS_H_
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