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1 // -*- mode: C++ -*- |
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2 |
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3 // Copyright (c) 2010, Google Inc. |
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4 // All rights reserved. |
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5 // |
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6 // Redistribution and use in source and binary forms, with or without |
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7 // modification, are permitted provided that the following conditions are |
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8 // met: |
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9 // |
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10 // * Redistributions of source code must retain the above copyright |
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11 // notice, this list of conditions and the following disclaimer. |
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12 // * Redistributions in binary form must reproduce the above |
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13 // copyright notice, this list of conditions and the following disclaimer |
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14 // in the documentation and/or other materials provided with the |
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15 // distribution. |
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16 // * Neither the name of Google Inc. nor the names of its |
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17 // contributors may be used to endorse or promote products derived from |
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18 // this software without specific prior written permission. |
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19 // |
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20 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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21 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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22 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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23 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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24 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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25 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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26 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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27 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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28 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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29 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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30 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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31 |
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32 // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com> |
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33 |
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34 // cfi_frame_info-inl.h: Definitions for cfi_frame_info.h inlined functions. |
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35 |
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36 #ifndef PROCESSOR_CFI_FRAME_INFO_INL_H_ |
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37 #define PROCESSOR_CFI_FRAME_INFO_INL_H_ |
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38 |
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39 #include <string.h> |
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40 |
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41 namespace google_breakpad { |
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42 |
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43 template <typename RegisterValueType, class RawContextType> |
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44 bool SimpleCFIWalker<RegisterValueType, RawContextType>::FindCallerRegisters( |
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45 const MemoryRegion &memory, |
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46 const CFIFrameInfo &cfi_frame_info, |
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47 const RawContextType &callee_context, |
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48 int callee_validity, |
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49 RawContextType *caller_context, |
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50 int *caller_validity) const { |
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51 typedef CFIFrameInfo::RegisterValueMap<RegisterValueType> ValueMap; |
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52 ValueMap callee_registers; |
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53 ValueMap caller_registers; |
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54 |
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55 // Populate callee_registers with register values from callee_context. |
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56 for (size_t i = 0; i < map_size_; i++) { |
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57 const RegisterSet &r = register_map_[i]; |
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58 if (callee_validity & r.validity_flag) |
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59 callee_registers.set(r.name, callee_context.*r.context_member); |
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60 } |
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61 |
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62 // Apply the rules, and see what register values they yield. |
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63 if (!cfi_frame_info |
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64 .FindCallerRegs<RegisterValueType>(callee_registers, memory, |
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65 &caller_registers)) |
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66 return false; |
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67 |
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68 // Populate *caller_context with the values the rules placed in |
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69 // caller_registers. |
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70 memset(caller_context, 0xda, sizeof(*caller_context)); |
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71 *caller_validity = 0; |
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72 for (size_t i = 0; i < map_size_; i++) { |
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73 const RegisterSet &r = register_map_[i]; |
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74 |
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75 // Did the rules provide a value for this register by its name? |
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76 bool found = false; |
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77 RegisterValueType v = caller_registers.get(&found, r.name); |
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78 if (found) { |
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79 caller_context->*r.context_member = v; |
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80 *caller_validity |= r.validity_flag; |
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81 continue; |
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82 } |
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83 |
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84 // Did the rules provide a value for this register under its |
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85 // alternate name? |
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86 if (r.alternate_name) { |
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87 found = false; |
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88 v = caller_registers.get(&found, r.alternate_name); |
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89 if (found) { |
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90 caller_context->*r.context_member = v; |
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91 *caller_validity |= r.validity_flag; |
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92 continue; |
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93 } |
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94 } |
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95 |
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96 // Is this a callee-saves register? The walker assumes that these |
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97 // still hold the caller's value if the CFI doesn't mention them. |
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98 // |
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99 // Note that other frame walkers may fail to recover callee-saves |
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100 // registers; for example, the x86 "traditional" strategy only |
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101 // recovers %eip, %esp, and %ebp, even though %ebx, %esi, and %edi |
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102 // are callee-saves, too. It is not correct to blindly set the |
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103 // valid bit for all callee-saves registers, without first |
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104 // checking its validity bit in the callee. |
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105 if (r.callee_saves && (callee_validity & r.validity_flag) != 0) { |
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106 caller_context->*r.context_member = callee_context.*r.context_member; |
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107 *caller_validity |= r.validity_flag; |
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108 continue; |
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109 } |
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110 |
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111 // Otherwise, the register's value is unknown. |
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112 } |
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113 |
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114 return true; |
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115 } |
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116 |
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117 } // namespace google_breakpad |
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118 |
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119 #endif // PROCESSOR_CFI_FRAME_INFO_INL_H_ |