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// Copyright (c) 2006, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef GOOGLE_BREAKPAD_PROCESSOR_STACK_FRAME_H__
#define GOOGLE_BREAKPAD_PROCESSOR_STACK_FRAME_H__
#include <string>
#include "common/using_std_string.h"
#include "google_breakpad/common/breakpad_types.h"
namespace google_breakpad {
class CodeModule;
struct StackFrame {
// Indicates how well the instruction pointer derived during
// stack walking is trusted. Since the stack walker can resort to
// stack scanning, it can wind up with dubious frames.
// In rough order of "trust metric".
enum FrameTrust {
FRAME_TRUST_NONE, // Unknown
FRAME_TRUST_SCAN, // Scanned the stack, found this
FRAME_TRUST_CFI_SCAN, // Found while scanning stack using call frame info
FRAME_TRUST_FP, // Derived from frame pointer
FRAME_TRUST_CFI, // Derived from call frame info
FRAME_TRUST_PREWALKED, // Explicitly provided by some external stack walker.
FRAME_TRUST_CONTEXT // Given as instruction pointer in a context
};
StackFrame()
: instruction(),
module(NULL),
function_name(),
function_base(),
source_file_name(),
source_line(),
source_line_base(),
trust(FRAME_TRUST_NONE) {}
virtual ~StackFrame() {}
// Return a string describing how this stack frame was found
// by the stackwalker.
string trust_description() const {
switch (trust) {
case StackFrame::FRAME_TRUST_CONTEXT:
return "given as instruction pointer in context";
case StackFrame::FRAME_TRUST_PREWALKED:
return "recovered by external stack walker";
case StackFrame::FRAME_TRUST_CFI:
return "call frame info";
case StackFrame::FRAME_TRUST_CFI_SCAN:
return "call frame info with scanning";
case StackFrame::FRAME_TRUST_FP:
return "previous frame's frame pointer";
case StackFrame::FRAME_TRUST_SCAN:
return "stack scanning";
default:
return "unknown";
}
}
// Return the actual return address, as saved on the stack or in a
// register. See the comments for 'instruction', below, for details.
virtual uint64_t ReturnAddress() const { return instruction; }
// The program counter location as an absolute virtual address.
//
// - For the innermost called frame in a stack, this will be an exact
// program counter or instruction pointer value.
//
// - For all other frames, this address is within the instruction that
// caused execution to branch to this frame's callee (although it may
// not point to the exact beginning of that instruction). This ensures
// that, when we look up the source code location for this frame, we
// get the source location of the call, not of the point at which
// control will resume when the call returns, which may be on the next
// line. (If the compiler knows the callee never returns, it may even
// place the call instruction at the very end of the caller's machine
// code, such that the "return address" (which will never be used)
// immediately after the call instruction is in an entirely different
// function, perhaps even from a different source file.)
//
// On some architectures, the return address as saved on the stack or in
// a register is fine for looking up the point of the call. On others, it
// requires adjustment. ReturnAddress returns the address as saved by the
// machine.
uint64_t instruction;
// The module in which the instruction resides.
const CodeModule *module;
// The function name, may be omitted if debug symbols are not available.
string function_name;
// The start address of the function, may be omitted if debug symbols
// are not available.
uint64_t function_base;
// The source file name, may be omitted if debug symbols are not available.
string source_file_name;
// The (1-based) source line number, may be omitted if debug symbols are
// not available.
int source_line;
// The start address of the source line, may be omitted if debug symbols
// are not available.
uint64_t source_line_base;
// Amount of trust the stack walker has in the instruction pointer
// of this frame.
FrameTrust trust;
};
} // namespace google_breakpad
#endif // GOOGLE_BREAKPAD_PROCESSOR_STACK_FRAME_H__