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 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* vim: set ts=8 sts=2 et sw=2 tw=80: */

 /* libunwind - a platform-independent unwind library

    Copyright 2011 Linaro Limited

 This file is part of libunwind.

 Permission is hereby granted, free of charge, to any person obtaining

 a copy of this software and associated documentation files (the

 "Software"), to deal in the Software without restriction, including

 without limitation the rights to use, copy, modify, merge, publish,

 distribute, sublicense, and/or sell copies of the Software, and to

 permit persons to whom the Software is furnished to do so, subject to

 the following conditions:

 The above copyright notice and this permission notice shall be

 included in all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE

 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION

 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */

 // Copyright (c) 2010, 2011 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.

 // Derived from libunwind, with extensive modifications.

 // This file is derived from the following files in

 // toolkit/crashreporter/google-breakpad:

 //   src/common/arm_ex_to_module.h

 //   src/common/memory_range.h

 //   src/common/arm_ex_reader.h

 #ifndef LulExidxExt_h

 #define LulExidxExt_h

 #include "LulMainInt.h"

 using lul::LExpr;

 using lul::RuleSet;

 using lul::SecMap;

 namespace lul {

 typedef enum extab_cmd {

   ARM_EXIDX_CMD_FINISH,

   ARM_EXIDX_CMD_SUB_FROM_VSP,

   ARM_EXIDX_CMD_ADD_TO_VSP,

   ARM_EXIDX_CMD_REG_POP,

   ARM_EXIDX_CMD_REG_TO_SP,

   ARM_EXIDX_CMD_VFP_POP,

   ARM_EXIDX_CMD_WREG_POP,

   ARM_EXIDX_CMD_WCGR_POP,

   ARM_EXIDX_CMD_RESERVED,

   ARM_EXIDX_CMD_REFUSED,

 } extab_cmd_t;

 struct exidx_entry {

   uint32_t addr;

   uint32_t data;

 };

 struct extab_data {

   extab_cmd_t cmd;

   uint32_t data;

 };

 enum extab_cmd_flags {

   ARM_EXIDX_VFP_SHIFT_16 = 1 << 16,

   ARM_EXIDX_VFP_FSTMD = 1 << 17, // distinguishes FSTMxxD from FSTMxxX

 };

 // Receives information from arm_ex_reader::ExceptionTableInfo

 // and adds it to the SecMap object

 // This is in effect the EXIDX summariser.

 class ARMExToModule {

  public:

    ARMExToModule(SecMap* smap, void(*log)(const char*)) : smap_(smap)

                                                         , log_(log) { }

   ~ARMExToModule() { }

   void AddStackFrame(uintptr_t addr, size_t size);

   int  ImproveStackFrame(const struct extab_data* edata);

   void DeleteStackFrame();

   void SubmitStackFrame();

  private:

   SecMap* smap_;

   LExpr   vsp_;        // Always appears to be of the form "sp + offset"

   RuleSet curr_rules_; // Also holds the address range being summarised

   // debugging message sink

   void (*log_)(const char*);

   int TranslateCmd(const struct extab_data* edata, LExpr& vsp);

 };

 // (derived from)

 // memory_range.h: Define the google_breakpad::MemoryRange class, which

 // is a lightweight wrapper with a pointer and a length to encapsulate

 // a contiguous range of memory.

 // A lightweight wrapper with a pointer and a length to encapsulate a

 // contiguous range of memory. It provides helper methods for checked

 // access of a subrange of the memory. Its implemementation does not

 // allocate memory or call into libc functions, and is thus safer to use

 // in a crashed environment.

 class MemoryRange {

  public:

   MemoryRange(const void* data, size_t length) {

     Set(data, length);

   }

   // Sets this memory range to point to |data| and its length to |length|.

   void Set(const void* data, size_t length) {

     data_ = reinterpret_cast<const uint8_t*>(data);

     // Always set |length_| to zero if |data_| is NULL.

     length_ = data ? length : 0;

   }

   // Returns true if this range covers a subrange of |sub_length| bytes

   // at |sub_offset| bytes of this memory range, or false otherwise.

   bool Covers(size_t sub_offset, size_t sub_length) const {

     // The following checks verify that:

     // 1. sub_offset is within [ 0 .. length_ - 1 ]

     // 2. sub_offset + sub_length is within

     //    [ sub_offset .. length_ ]

     return sub_offset < length_ &&

            sub_offset + sub_length >= sub_offset &&

            sub_offset + sub_length <= length_;

   }

   // Returns a pointer to the beginning of this memory range.

   const uint8_t* data() const { return data_; }

   // Returns the length, in bytes, of this memory range.

   size_t length() const { return length_; }

  private:

   // Pointer to the beginning of this memory range.

   const uint8_t* data_;

   // Length, in bytes, of this memory range.

   size_t length_;

 };

 // This class is a reader for ARM unwind information

 // from .ARM.exidx and .ARM.extab sections.

 class ExceptionTableInfo {

  public:

   ExceptionTableInfo(const char* exidx, size_t exidx_size,

                      const char* extab, size_t extab_size,

                      uint32_t text_last_svma,

                      lul::ARMExToModule* handler,

                      const char* mapping_addr,

                      uint32_t loading_addr,

                      uintptr_t text_bias,

                      void (*log)(const char*))

       : mr_exidx_(lul::MemoryRange(exidx, exidx_size)),

         mr_extab_(lul::MemoryRange(extab, extab_size)),

         text_last_svma_(text_last_svma),

         handler_(handler), mapping_addr_(mapping_addr),

         loading_addr_(loading_addr),

         text_bias_(text_bias),

         log_(log) { }

   ~ExceptionTableInfo() { }

   // Parses the entries in .ARM.exidx and possibly

   // in .ARM.extab tables, reports what we find to

   // arm_ex_to_module::ARMExToModule.

   void Start();

  private:

   lul::MemoryRange mr_exidx_;

   lul::MemoryRange mr_extab_;

   uint32_t text_last_svma_;

   lul::ARMExToModule* handler_;

   const char* mapping_addr_;

   uint32_t loading_addr_;

   uintptr_t text_bias_;

   // debugging message sink

   void (*log_)(const char*);

   enum ExExtractResult {

     ExSuccess,        // success

     ExInBufOverflow,  // out-of-range while reading .exidx

     ExOutBufOverflow, // output buffer is too small

     ExCantUnwind,     // this function is marked CANT_UNWIND

     ExCantRepresent,  // entry valid, but we can't represent it

     ExInvalid         // entry is invalid

   };

   ExExtractResult

     ExtabEntryExtract(const struct lul::exidx_entry* entry,

                       uint8_t* buf, size_t buf_size,

                       /*OUT*/size_t* buf_used);

   int ExtabEntryDecode(const uint8_t* buf, size_t buf_size);

 };

 } // namespace lul

 #endif // LulExidxExt_h