move libevmasm

1 files changed, 181 insertions, 0 deletions

diff --git a/libevmasm/SemanticInformation.cpp b/libevmasm/SemanticInformation.cpp
new file mode 100644
index 00000000..ea579b83
--- /dev/null
+++ b/libevmasm/SemanticInformation.cpp
@@ -0,0 +1,181 @@
+/*
+	This file is part of cpp-ethereum.
+
+	cpp-ethereum is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	cpp-ethereum is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @file SemanticInformation.cpp
+ * @author Christian <c@ethdev.com>
+ * @date 2015
+ * Helper to provide semantic information about assembly items.
+ */
+
+#include <libevmasm/SemanticInformation.h>
+#include <libevmasm/AssemblyItem.h>
+
+using namespace std;
+using namespace dev;
+using namespace dev::eth;
+
+bool SemanticInformation::breaksCSEAnalysisBlock(AssemblyItem const& _item)
+{
+	switch (_item.type())
+	{
+	default:
+	case UndefinedItem:
+	case Tag:
+		return true;
+	case Push:
+	case PushString:
+	case PushTag:
+	case PushSub:
+	case PushSubSize:
+	case PushProgramSize:
+	case PushData:
+	case PushLibraryAddress:
+		return false;
+	case Operation:
+	{
+		if (isSwapInstruction(_item) || isDupInstruction(_item))
+			return false;
+		if (_item.instruction() == Instruction::GAS || _item.instruction() == Instruction::PC)
+			return true; // GAS and PC assume a specific order of opcodes
+		if (_item.instruction() == Instruction::MSIZE)
+			return true; // msize is modified already by memory access, avoid that for now
+		InstructionInfo info = instructionInfo(_item.instruction());
+		if (_item.instruction() == Instruction::SSTORE)
+			return false;
+		if (_item.instruction() == Instruction::MSTORE)
+			return false;
+		//@todo: We do not handle the following memory instructions for now:
+		// calldatacopy, codecopy, extcodecopy, mstore8,
+		// msize (note that msize also depends on memory read access)
+
+		// the second requirement will be lifted once it is implemented
+		return info.sideEffects || info.args > 2;
+	}
+	}
+}
+
+bool SemanticInformation::isCommutativeOperation(AssemblyItem const& _item)
+{
+	if (_item.type() != Operation)
+		return false;
+	switch (_item.instruction())
+	{
+	case Instruction::ADD:
+	case Instruction::MUL:
+	case Instruction::EQ:
+	case Instruction::AND:
+	case Instruction::OR:
+	case Instruction::XOR:
+		return true;
+	default:
+		return false;
+	}
+}
+
+bool SemanticInformation::isDupInstruction(AssemblyItem const& _item)
+{
+	if (_item.type() != Operation)
+		return false;
+	return Instruction::DUP1 <= _item.instruction() && _item.instruction() <= Instruction::DUP16;
+}
+
+bool SemanticInformation::isSwapInstruction(AssemblyItem const& _item)
+{
+	if (_item.type() != Operation)
+		return false;
+	return Instruction::SWAP1 <= _item.instruction() && _item.instruction() <= Instruction::SWAP16;
+}
+
+bool SemanticInformation::isJumpInstruction(AssemblyItem const& _item)
+{
+	return _item == AssemblyItem(Instruction::JUMP) || _item == AssemblyItem(Instruction::JUMPI);
+}
+
+bool SemanticInformation::altersControlFlow(AssemblyItem const& _item)
+{
+	if (_item.type() != Operation)
+		return false;
+	switch (_item.instruction())
+	{
+	// note that CALL, CALLCODE and CREATE do not really alter the control flow, because we
+	// continue on the next instruction
+	case Instruction::JUMP:
+	case Instruction::JUMPI:
+	case Instruction::RETURN:
+	case Instruction::SUICIDE:
+	case Instruction::STOP:
+		return true;
+	default:
+		return false;
+	}
+}
+
+
+bool SemanticInformation::isDeterministic(AssemblyItem const& _item)
+{
+	if (_item.type() != Operation)
+		return true;
+
+	switch (_item.instruction())
+	{
+	case Instruction::CALL:
+	case Instruction::CALLCODE:
+	case Instruction::DELEGATECALL:
+	case Instruction::CREATE:
+	case Instruction::GAS:
+	case Instruction::PC:
+	case Instruction::MSIZE: // depends on previous writes and reads, not only on content
+	case Instruction::BALANCE: // depends on previous calls
+	case Instruction::EXTCODESIZE:
+		return false;
+	default:
+		return true;
+	}
+}
+
+bool SemanticInformation::invalidatesMemory(Instruction _instruction)
+{
+	switch (_instruction)
+	{
+	case Instruction::CALLDATACOPY:
+	case Instruction::CODECOPY:
+	case Instruction::EXTCODECOPY:
+	case Instruction::MSTORE:
+	case Instruction::MSTORE8:
+	case Instruction::CALL:
+	case Instruction::CALLCODE:
+	case Instruction::DELEGATECALL:
+		return true;
+	default:
+		return false;
+	}
+}
+
+bool SemanticInformation::invalidatesStorage(Instruction _instruction)
+{
+	switch (_instruction)
+	{
+	case Instruction::CALL:
+	case Instruction::CALLCODE:
+	case Instruction::DELEGATECALL:
+	case Instruction::CREATE:
+	case Instruction::SSTORE:
+		return true;
+	default:
+		return false;
+	}
+}