libelffile/dwarf/debug_line_opcode_writer.h - LeafOS-Project/android_art - Gitiles

 /*
  * Copyright (C) 2015 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #ifndef ART_LIBELFFILE_DWARF_DEBUG_LINE_OPCODE_WRITER_H_
 #define ART_LIBELFFILE_DWARF_DEBUG_LINE_OPCODE_WRITER_H_

 #include <cstdint>

 #include "dwarf/dwarf_constants.h"
 #include "dwarf/writer.h"

 namespace art {
 namespace dwarf {

 // Writer for the .debug_line opcodes (DWARF-3).
 // The writer is very light-weight, however it will do the following for you:
 //  * Choose the most compact encoding of a given opcode.
 //  * Keep track of current state and convert absolute values to deltas.
 //  * Divide by header-defined factors as appropriate.
 template<typename Vector = std::vector<uint8_t>>
 class DebugLineOpCodeWriter final : private Writer<Vector> {
   static_assert(std::is_same<typename Vector::value_type, uint8_t>::value, "Invalid value type");

  public:
   static constexpr int kOpcodeBase = 13;
   static constexpr bool kDefaultIsStmt = false;
   static constexpr int kLineBase = -5;
   static constexpr int kLineRange = 14;

   void AddRow() {
     this->PushUint8(DW_LNS_copy);
   }

   void AdvancePC(uint64_t absolute_address) {
     DCHECK_NE(current_address_, 0u);  // Use SetAddress for the first advance.
     DCHECK_GE(absolute_address, current_address_);
     if (absolute_address != current_address_) {
       uint64_t delta = FactorCodeOffset(absolute_address - current_address_);
       if (delta <= INT32_MAX) {
         this->PushUint8(DW_LNS_advance_pc);
         this->PushUleb128(static_cast<int>(delta));
         current_address_ = absolute_address;
       } else {
         SetAddress(absolute_address);
       }
     }
   }

   void AdvanceLine(int absolute_line) {
     int delta = absolute_line - current_line_;
     if (delta != 0) {
       this->PushUint8(DW_LNS_advance_line);
       this->PushSleb128(delta);
       current_line_ = absolute_line;
     }
   }

   void SetFile(int file) {
     if (current_file_ != file) {
       this->PushUint8(DW_LNS_set_file);
       this->PushUleb128(file);
       current_file_ = file;
     }
   }

   void SetColumn(int column) {
     this->PushUint8(DW_LNS_set_column);
     this->PushUleb128(column);
   }

   void SetIsStmt(bool is_stmt) {
     if (is_stmt_ != is_stmt) {
       this->PushUint8(DW_LNS_negate_stmt);
       is_stmt_ = is_stmt;
     }
   }

   void SetBasicBlock() {
     this->PushUint8(DW_LNS_set_basic_block);
   }

   void SetPrologueEnd() {
     uses_dwarf3_features_ = true;
     this->PushUint8(DW_LNS_set_prologue_end);
   }

   void SetEpilogueBegin() {
     uses_dwarf3_features_ = true;
     this->PushUint8(DW_LNS_set_epilogue_begin);
   }

   void SetISA(int isa) {
     uses_dwarf3_features_ = true;
     this->PushUint8(DW_LNS_set_isa);
     this->PushUleb128(isa);
   }

   void EndSequence() {
     this->PushUint8(0);
     this->PushUleb128(1);
     this->PushUint8(DW_LNE_end_sequence);
     current_address_ = 0;
     current_file_ = 1;
     current_line_ = 1;
     is_stmt_ = kDefaultIsStmt;
   }

   // Uncoditionally set address using the long encoding.
   // This gives the linker opportunity to relocate the address.
   void SetAddress(uint64_t absolute_address) {
     DCHECK_GE(absolute_address, current_address_);
     FactorCodeOffset(absolute_address);  // Check if it is factorable.
     this->PushUint8(0);
     if (use_64bit_address_) {
       this->PushUleb128(1 + 8);
       this->PushUint8(DW_LNE_set_address);
       patch_locations_.push_back(this->data()->size());
       this->PushUint64(absolute_address);
     } else {
       this->PushUleb128(1 + 4);
       this->PushUint8(DW_LNE_set_address);
       patch_locations_.push_back(this->data()->size());
       this->PushUint32(absolute_address);
     }
     current_address_ = absolute_address;
   }

   void DefineFile(const char* filename,
                   int directory_index,
                   int modification_time,
                   int file_size) {
     int size = 1 +
                strlen(filename) + 1 +
                UnsignedLeb128Size(directory_index) +
                UnsignedLeb128Size(modification_time) +
                UnsignedLeb128Size(file_size);
     this->PushUint8(0);
     this->PushUleb128(size);
     size_t start = data()->size();
     this->PushUint8(DW_LNE_define_file);
     this->PushString(filename);
     this->PushUleb128(directory_index);
     this->PushUleb128(modification_time);
     this->PushUleb128(file_size);
     DCHECK_EQ(start + size, data()->size());
   }

   // Compact address and line opcode.
   void AddRow(uint64_t absolute_address, int absolute_line) {
     DCHECK_GE(absolute_address, current_address_);

     // If the address is definitely too far, use the long encoding.
     uint64_t delta_address = FactorCodeOffset(absolute_address - current_address_);
     if (delta_address > UINT8_MAX) {
       AdvancePC(absolute_address);
       delta_address = 0;
     }

     // If the line is definitely too far, use the long encoding.
     int delta_line = absolute_line - current_line_;
     if (!(kLineBase <= delta_line && delta_line < kLineBase + kLineRange)) {
       AdvanceLine(absolute_line);
       delta_line = 0;
     }

     // Both address and line should be reasonable now.  Use the short encoding.
     int opcode = kOpcodeBase + (delta_line - kLineBase) +
                  (static_cast<int>(delta_address) * kLineRange);
     if (opcode > UINT8_MAX) {
       // If the address is still too far, try to increment it by const amount.
       int const_advance = (0xFF - kOpcodeBase) / kLineRange;
       opcode -= (kLineRange * const_advance);
       if (opcode <= UINT8_MAX) {
         this->PushUint8(DW_LNS_const_add_pc);
       } else {
         // Give up and use long encoding for address.
         AdvancePC(absolute_address);
         // Still use the opcode to do line advance and copy.
         opcode = kOpcodeBase + (delta_line - kLineBase);
       }
     }
     DCHECK(kOpcodeBase <= opcode && opcode <= 0xFF);
     this->PushUint8(opcode);  // Special opcode.
     current_line_ = absolute_line;
     current_address_ = absolute_address;
   }

   int GetCodeFactorBits() const {
     return code_factor_bits_;
   }

   uint64_t CurrentAddress() const {
     return current_address_;
   }

   int CurrentFile() const {
     return current_file_;
   }

   int CurrentLine() const {
     return current_line_;
   }

   const std::vector<uintptr_t>& GetPatchLocations() const {
     return patch_locations_;
   }

   using Writer<Vector>::data;

   DebugLineOpCodeWriter(bool use64bitAddress,
                         int codeFactorBits,
                         const typename Vector::allocator_type& alloc =
                             typename Vector::allocator_type())
       : Writer<Vector>(&opcodes_),
         opcodes_(alloc),
         uses_dwarf3_features_(false),
         use_64bit_address_(use64bitAddress),
         code_factor_bits_(codeFactorBits),
         current_address_(0),
         current_file_(1),
         current_line_(1),
         is_stmt_(kDefaultIsStmt) {
   }

  private:
   uint64_t FactorCodeOffset(uint64_t offset) const {
     DCHECK_GE(code_factor_bits_, 0);
     DCHECK_EQ((offset >> code_factor_bits_) << code_factor_bits_, offset);
     return offset >> code_factor_bits_;
   }

   Vector opcodes_;
   bool uses_dwarf3_features_;
   bool use_64bit_address_;
   int code_factor_bits_;
   uint64_t current_address_;
   int current_file_;
   int current_line_;
   bool is_stmt_;
   std::vector<uintptr_t> patch_locations_;

   DISALLOW_COPY_AND_ASSIGN(DebugLineOpCodeWriter);
 };

 }  // namespace dwarf
 }  // namespace art

 #endif  // ART_LIBELFFILE_DWARF_DEBUG_LINE_OPCODE_WRITER_H_
	/*
	* Copyright (C) 2015 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#ifndef ART_LIBELFFILE_DWARF_DEBUG_LINE_OPCODE_WRITER_H_
	#define ART_LIBELFFILE_DWARF_DEBUG_LINE_OPCODE_WRITER_H_

	#include <cstdint>

	#include "dwarf/dwarf_constants.h"
	#include "dwarf/writer.h"

	namespace art {
	namespace dwarf {

	// Writer for the .debug_line opcodes (DWARF-3).
	// The writer is very light-weight, however it will do the following for you:
	// * Choose the most compact encoding of a given opcode.
	// * Keep track of current state and convert absolute values to deltas.
	// * Divide by header-defined factors as appropriate.
	template<typename Vector = std::vector<uint8_t>>
	class DebugLineOpCodeWriter final : private Writer<Vector> {
	static_assert(std::is_same<typename Vector::value_type, uint8_t>::value, "Invalid value type");

	public:
	static constexpr int kOpcodeBase = 13;
	static constexpr bool kDefaultIsStmt = false;
	static constexpr int kLineBase = -5;
	static constexpr int kLineRange = 14;

	void AddRow() {
	this->PushUint8(DW_LNS_copy);
	}

	void AdvancePC(uint64_t absolute_address) {
	DCHECK_NE(current_address_, 0u); // Use SetAddress for the first advance.
	DCHECK_GE(absolute_address, current_address_);
	if (absolute_address != current_address_) {
	uint64_t delta = FactorCodeOffset(absolute_address - current_address_);
	if (delta <= INT32_MAX) {
	this->PushUint8(DW_LNS_advance_pc);
	this->PushUleb128(static_cast<int>(delta));
	current_address_ = absolute_address;
	} else {
	SetAddress(absolute_address);
	}
	}
	}

	void AdvanceLine(int absolute_line) {
	int delta = absolute_line - current_line_;
	if (delta != 0) {
	this->PushUint8(DW_LNS_advance_line);
	this->PushSleb128(delta);
	current_line_ = absolute_line;
	}
	}

	void SetFile(int file) {
	if (current_file_ != file) {
	this->PushUint8(DW_LNS_set_file);
	this->PushUleb128(file);
	current_file_ = file;
	}
	}

	void SetColumn(int column) {
	this->PushUint8(DW_LNS_set_column);
	this->PushUleb128(column);
	}

	void SetIsStmt(bool is_stmt) {
	if (is_stmt_ != is_stmt) {
	this->PushUint8(DW_LNS_negate_stmt);
	is_stmt_ = is_stmt;
	}
	}

	void SetBasicBlock() {
	this->PushUint8(DW_LNS_set_basic_block);
	}

	void SetPrologueEnd() {
	uses_dwarf3_features_ = true;
	this->PushUint8(DW_LNS_set_prologue_end);
	}

	void SetEpilogueBegin() {
	uses_dwarf3_features_ = true;
	this->PushUint8(DW_LNS_set_epilogue_begin);
	}

	void SetISA(int isa) {
	uses_dwarf3_features_ = true;
	this->PushUint8(DW_LNS_set_isa);
	this->PushUleb128(isa);
	}

	void EndSequence() {
	this->PushUint8(0);
	this->PushUleb128(1);
	this->PushUint8(DW_LNE_end_sequence);
	current_address_ = 0;
	current_file_ = 1;
	current_line_ = 1;
	is_stmt_ = kDefaultIsStmt;
	}

	// Uncoditionally set address using the long encoding.
	// This gives the linker opportunity to relocate the address.
	void SetAddress(uint64_t absolute_address) {
	DCHECK_GE(absolute_address, current_address_);
	FactorCodeOffset(absolute_address); // Check if it is factorable.
	this->PushUint8(0);
	if (use_64bit_address_) {
	this->PushUleb128(1 + 8);
	this->PushUint8(DW_LNE_set_address);
	patch_locations_.push_back(this->data()->size());
	this->PushUint64(absolute_address);
	} else {
	this->PushUleb128(1 + 4);
	this->PushUint8(DW_LNE_set_address);
	patch_locations_.push_back(this->data()->size());
	this->PushUint32(absolute_address);
	}
	current_address_ = absolute_address;
	}

	void DefineFile(const char* filename,
	int directory_index,
	int modification_time,
	int file_size) {
	int size = 1 +
	strlen(filename) + 1 +
	UnsignedLeb128Size(directory_index) +
	UnsignedLeb128Size(modification_time) +
	UnsignedLeb128Size(file_size);
	this->PushUint8(0);
	this->PushUleb128(size);
	size_t start = data()->size();
	this->PushUint8(DW_LNE_define_file);
	this->PushString(filename);
	this->PushUleb128(directory_index);
	this->PushUleb128(modification_time);
	this->PushUleb128(file_size);
	DCHECK_EQ(start + size, data()->size());
	}

	// Compact address and line opcode.
	void AddRow(uint64_t absolute_address, int absolute_line) {
	DCHECK_GE(absolute_address, current_address_);

	// If the address is definitely too far, use the long encoding.
	uint64_t delta_address = FactorCodeOffset(absolute_address - current_address_);
	if (delta_address > UINT8_MAX) {
	AdvancePC(absolute_address);
	delta_address = 0;
	}

	// If the line is definitely too far, use the long encoding.
	int delta_line = absolute_line - current_line_;
	if (!(kLineBase <= delta_line && delta_line < kLineBase + kLineRange)) {
	AdvanceLine(absolute_line);
	delta_line = 0;
	}

	// Both address and line should be reasonable now. Use the short encoding.
	int opcode = kOpcodeBase + (delta_line - kLineBase) +
	(static_cast<int>(delta_address) * kLineRange);
	if (opcode > UINT8_MAX) {
	// If the address is still too far, try to increment it by const amount.
	int const_advance = (0xFF - kOpcodeBase) / kLineRange;
	opcode -= (kLineRange * const_advance);
	if (opcode <= UINT8_MAX) {
	this->PushUint8(DW_LNS_const_add_pc);
	} else {
	// Give up and use long encoding for address.
	AdvancePC(absolute_address);
	// Still use the opcode to do line advance and copy.
	opcode = kOpcodeBase + (delta_line - kLineBase);
	}
	}
	DCHECK(kOpcodeBase <= opcode && opcode <= 0xFF);
	this->PushUint8(opcode); // Special opcode.
	current_line_ = absolute_line;
	current_address_ = absolute_address;
	}

	int GetCodeFactorBits() const {
	return code_factor_bits_;
	}

	uint64_t CurrentAddress() const {
	return current_address_;
	}

	int CurrentFile() const {
	return current_file_;
	}

	int CurrentLine() const {
	return current_line_;
	}

	const std::vector<uintptr_t>& GetPatchLocations() const {
	return patch_locations_;
	}

	using Writer<Vector>::data;

	DebugLineOpCodeWriter(bool use64bitAddress,
	int codeFactorBits,
	const typename Vector::allocator_type& alloc =
	typename Vector::allocator_type())
	: Writer<Vector>(&opcodes_),
	opcodes_(alloc),
	uses_dwarf3_features_(false),
	use_64bit_address_(use64bitAddress),
	code_factor_bits_(codeFactorBits),
	current_address_(0),
	current_file_(1),
	current_line_(1),
	is_stmt_(kDefaultIsStmt) {
	}

	private:
	uint64_t FactorCodeOffset(uint64_t offset) const {
	DCHECK_GE(code_factor_bits_, 0);
	DCHECK_EQ((offset >> code_factor_bits_) << code_factor_bits_, offset);
	return offset >> code_factor_bits_;
	}

	Vector opcodes_;
	bool uses_dwarf3_features_;
	bool use_64bit_address_;
	int code_factor_bits_;
	uint64_t current_address_;
	int current_file_;
	int current_line_;
	bool is_stmt_;
	std::vector<uintptr_t> patch_locations_;

	DISALLOW_COPY_AND_ASSIGN(DebugLineOpCodeWriter);
	};

	} // namespace dwarf
	} // namespace art

	#endif // ART_LIBELFFILE_DWARF_DEBUG_LINE_OPCODE_WRITER_H_