Merge "Implement new DEX PC lookup scheme." (c3aabea0) · Commits · e / os / android_system_core

libunwindstack/DwarfOp.cpp

+40 −14

Original line number	Diff line number	Diff line
		@@ -36,13 +36,45 @@ template <typename AddressType>
		constexpr typename DwarfOp<AddressType>::OpCallback DwarfOp<AddressType>::kCallbackTable[256];

		template <typename AddressType>
		bool DwarfOp<AddressType>::Eval(uint64_t start, uint64_t end, uint8_t dwarf_version) {
		uint32_t iterations = 0;
		bool DwarfOp<AddressType>::Eval(uint64_t start, uint64_t end) {
		is_register_ = false;
		stack_.clear();
		memory_->set_cur_offset(start);
		dex_pc_set_ = false;

		// Unroll the first Decode calls to be able to check for a special
		// sequence of ops and values that indicate this is the dex pc.
		// The pattern is:
		// OP_const4u (0x0c) 'D' 'E' 'X' '1'
		// OP_drop (0x13)
		if (memory_->cur_offset() < end) {
		if (!Decode()) {
		return false;
		}
		} else {
		return true;
		}
		bool check_for_drop;
		if (cur_op_ == 0x0c && operands_.back() == 0x31584544) {
		check_for_drop = true;
		} else {
		check_for_drop = false;
		}
		if (memory_->cur_offset() < end) {
		if (!Decode()) {
		return false;
		}
		} else {
		return true;
		}

		if (check_for_drop && cur_op_ == 0x13) {
		dex_pc_set_ = true;
		}

		uint32_t iterations = 2;
		while (memory_->cur_offset() < end) {
		if (!Decode(dwarf_version)) {
		if (!Decode()) {
		return false;
		}
		// To protect against a branch that creates an infinite loop,
		@@ -56,7 +88,7 @@ bool DwarfOp<AddressType>::Eval(uint64_t start, uint64_t end, uint8_t dwarf_vers
		}

		template <typename AddressType>
		bool DwarfOp<AddressType>::Decode(uint8_t dwarf_version) {
		bool DwarfOp<AddressType>::Decode() {
		last_error_.code = DWARF_ERROR_NONE;
		if (!memory_->ReadBytes(&cur_op_, 1)) {
		last_error_.code = DWARF_ERROR_MEMORY_INVALID;
		@@ -71,12 +103,6 @@ bool DwarfOp<AddressType>::Decode(uint8_t dwarf_version) {
		return false;
		}

		// Check for an unsupported opcode.
		if (dwarf_version < op->supported_version) {
		last_error_.code = DWARF_ERROR_ILLEGAL_VALUE;
		return false;
		}

		// Make sure that the required number of stack elements is available.
		if (stack_.size() < op->num_required_stack_values) {
		last_error_.code = DWARF_ERROR_STACK_INDEX_NOT_VALID;
		@@ -434,22 +460,22 @@ bool DwarfOp<AddressType>::op_regx() {
		template <typename AddressType>
		bool DwarfOp<AddressType>::op_breg() {
		uint16_t reg = cur_op() - 0x70;
		if (reg >= regs_->total_regs()) {
		if (reg >= regs_info_->Total()) {
		last_error_.code = DWARF_ERROR_ILLEGAL_VALUE;
		return false;
		}
		stack_.push_front((*regs_)[reg] + OperandAt(0));
		stack_.push_front(regs_info_->Get(reg) + OperandAt(0));
		return true;
		}

		template <typename AddressType>
		bool DwarfOp<AddressType>::op_bregx() {
		AddressType reg = OperandAt(0);
		if (reg >= regs_->total_regs()) {
		if (reg >= regs_info_->Total()) {
		last_error_.code = DWARF_ERROR_ILLEGAL_VALUE;
		return false;
		}
		stack_.push_front((*regs_)[reg] + OperandAt(1));
		stack_.push_front(regs_info_->Get(reg) + OperandAt(1));
		return true;
		}