1 // Copyright (c) 2006, Google Inc. 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 #ifndef GOOGLE_BREAKPAD_PROCESSOR_STACK_FRAME_H__ 31 #define GOOGLE_BREAKPAD_PROCESSOR_STACK_FRAME_H__ 32 33 #include <string> 34 35 #include "common/using_std_string.h" 36 #include "google_breakpad/common/breakpad_types.h" 37 38 namespace google_breakpad { 39 40 class CodeModule; 41 42 struct StackFrame { 43 // Indicates how well the instruction pointer derived during 44 // stack walking is trusted. Since the stack walker can resort to 45 // stack scanning, it can wind up with dubious frames. 46 // In rough order of "trust metric". 47 enum FrameTrust { 48 FRAME_TRUST_NONE, // Unknown 49 FRAME_TRUST_SCAN, // Scanned the stack, found this 50 FRAME_TRUST_CFI_SCAN, // Found while scanning stack using call frame info 51 FRAME_TRUST_FP, // Derived from frame pointer 52 FRAME_TRUST_CFI, // Derived from call frame info 53 FRAME_TRUST_PREWALKED, // Explicitly provided by some external stack walker. 54 FRAME_TRUST_CONTEXT // Given as instruction pointer in a context 55 }; 56 StackFrameStackFrame57 StackFrame() 58 : instruction(), 59 module(NULL), 60 function_name(), 61 function_base(), 62 source_file_name(), 63 source_line(), 64 source_line_base(), 65 trust(FRAME_TRUST_NONE) {} ~StackFrameStackFrame66 virtual ~StackFrame() {} 67 68 // Return a string describing how this stack frame was found 69 // by the stackwalker. trust_descriptionStackFrame70 string trust_description() const { 71 switch (trust) { 72 case StackFrame::FRAME_TRUST_CONTEXT: 73 return "given as instruction pointer in context"; 74 case StackFrame::FRAME_TRUST_PREWALKED: 75 return "recovered by external stack walker"; 76 case StackFrame::FRAME_TRUST_CFI: 77 return "call frame info"; 78 case StackFrame::FRAME_TRUST_CFI_SCAN: 79 return "call frame info with scanning"; 80 case StackFrame::FRAME_TRUST_FP: 81 return "previous frame's frame pointer"; 82 case StackFrame::FRAME_TRUST_SCAN: 83 return "stack scanning"; 84 default: 85 return "unknown"; 86 } 87 }; 88 89 // Return the actual return address, as saved on the stack or in a 90 // register. See the comments for 'instruction', below, for details. ReturnAddressStackFrame91 virtual uint64_t ReturnAddress() const { return instruction; } 92 93 // The program counter location as an absolute virtual address. 94 // 95 // - For the innermost called frame in a stack, this will be an exact 96 // program counter or instruction pointer value. 97 // 98 // - For all other frames, this address is within the instruction that 99 // caused execution to branch to this frame's callee (although it may 100 // not point to the exact beginning of that instruction). This ensures 101 // that, when we look up the source code location for this frame, we 102 // get the source location of the call, not of the point at which 103 // control will resume when the call returns, which may be on the next 104 // line. (If the compiler knows the callee never returns, it may even 105 // place the call instruction at the very end of the caller's machine 106 // code, such that the "return address" (which will never be used) 107 // immediately after the call instruction is in an entirely different 108 // function, perhaps even from a different source file.) 109 // 110 // On some architectures, the return address as saved on the stack or in 111 // a register is fine for looking up the point of the call. On others, it 112 // requires adjustment. ReturnAddress returns the address as saved by the 113 // machine. 114 uint64_t instruction; 115 116 // The module in which the instruction resides. 117 const CodeModule *module; 118 119 // The function name, may be omitted if debug symbols are not available. 120 string function_name; 121 122 // The start address of the function, may be omitted if debug symbols 123 // are not available. 124 uint64_t function_base; 125 126 // The source file name, may be omitted if debug symbols are not available. 127 string source_file_name; 128 129 // The (1-based) source line number, may be omitted if debug symbols are 130 // not available. 131 int source_line; 132 133 // The start address of the source line, may be omitted if debug symbols 134 // are not available. 135 uint64_t source_line_base; 136 137 // Amount of trust the stack walker has in the instruction pointer 138 // of this frame. 139 FrameTrust trust; 140 }; 141 142 } // namespace google_breakpad 143 144 #endif // GOOGLE_BREAKPAD_PROCESSOR_STACK_FRAME_H__ 145