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 // -*- mode: C++ -*-

 // Copyright (c) 2010, Google Inc.

 // All rights reserved.

 //

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 // 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

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 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>

 // cfi_frame_info-inl.h: Definitions for cfi_frame_info.h inlined functions.

 #ifndef PROCESSOR_CFI_FRAME_INFO_INL_H_

 #define PROCESSOR_CFI_FRAME_INFO_INL_H_

 #include <string.h>

 namespace google_breakpad {

 template <typename RegisterValueType, class RawContextType>

 bool SimpleCFIWalker<RegisterValueType, RawContextType>::FindCallerRegisters(

     const MemoryRegion &memory,

     const CFIFrameInfo &cfi_frame_info,

     const RawContextType &callee_context,

     int callee_validity,

     RawContextType *caller_context,

     int *caller_validity) const {

   typedef CFIFrameInfo::RegisterValueMap<RegisterValueType> ValueMap;

   ValueMap callee_registers;

   ValueMap caller_registers;

   // Populate callee_registers with register values from callee_context.

   for (size_t i = 0; i < map_size_; i++) {

     const RegisterSet &r = register_map_[i];

     if (callee_validity & r.validity_flag)

       callee_registers.set(r.name, callee_context.*r.context_member);

   }

   // Apply the rules, and see what register values they yield.

   if (!cfi_frame_info

        .FindCallerRegs<RegisterValueType>(callee_registers, memory,

                                           &caller_registers))

     return false;

   // Populate *caller_context with the values the rules placed in

   // caller_registers.

   memset(caller_context, 0xda, sizeof(*caller_context));

   *caller_validity = 0;

   for (size_t i = 0; i < map_size_; i++) {

     const RegisterSet &r = register_map_[i];

     // Did the rules provide a value for this register by its name?

     bool found = false;

     RegisterValueType v = caller_registers.get(&found, r.name);

     if (found) {

       caller_context->*r.context_member = v;

       *caller_validity |= r.validity_flag;

       continue;

     }

     // Did the rules provide a value for this register under its

     // alternate name?

     if (r.alternate_name) {

       found = false;

       v = caller_registers.get(&found, r.alternate_name);

       if (found) {

         caller_context->*r.context_member = v;

         *caller_validity |= r.validity_flag;

         continue;

       }

     }

     // Is this a callee-saves register? The walker assumes that these

     // still hold the caller's value if the CFI doesn't mention them.

     //

     // Note that other frame walkers may fail to recover callee-saves

     // registers; for example, the x86 "traditional" strategy only

     // recovers %eip, %esp, and %ebp, even though %ebx, %esi, and %edi

     // are callee-saves, too. It is not correct to blindly set the

     // valid bit for all callee-saves registers, without first

     // checking its validity bit in the callee.

     if (r.callee_saves && (callee_validity & r.validity_flag) != 0) {

       caller_context->*r.context_member = callee_context.*r.context_member;

       *caller_validity |= r.validity_flag;

       continue;

     }

     // Otherwise, the register's value is unknown.

   }

   return true;

 }

 } // namespace google_breakpad

 #endif // PROCESSOR_CFI_FRAME_INFO_INL_H_