From d005896a0b5c33623abad685dca19c8f2768048f Mon Sep 17 00:00:00 2001
From: artur-zawlocki <artur.zawlocki@gmail.com>
Date: Tue, 14 Oct 2014 14:52:15 +0100
Subject: [PATCH] Initial implementation for CALLDATACOPY [Delivers #80644732]

---
 evmcc/Compiler.cpp | 30 ++++++++++++++++++++++++++++++
 evmcc/Ext.cpp      |  6 +++---
 evmcc/Ext.h        |  1 +
 evmcc/Memory.cpp   |  5 +++++
 evmcc/Memory.h     |  1 +
 5 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/evmcc/Compiler.cpp b/evmcc/Compiler.cpp
index 5857040f8..47cbbf5c1 100644
--- a/evmcc/Compiler.cpp
+++ b/evmcc/Compiler.cpp
@@ -736,6 +736,36 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 				break;
 			}
 
+			case Instruction::CALLDATACOPY:
+			{
+				auto zero256 = ConstantInt::get(Type::i256, 0);
+
+				auto destMemIdx = stack.pop();
+				auto srcDataIdx = stack.pop();
+				auto reqByteCount = stack.pop();
+
+				// FIXME: ensure memory size reqMemSize.
+				auto reqMemSize = builder.CreateAdd(destMemIdx, reqByteCount);
+				auto reqMemWord = builder.CreateSub(reqMemSize, ConstantInt::get(Type::i256, 32));
+				memory.loadWord(reqMemWord);
+
+				auto memPtr = memory.getData();
+				auto destPtr = builder.CreateGEP(memPtr, destMemIdx);
+
+				auto calldataPtr = ext.calldata();
+				auto srcPtr = builder.CreateGEP(calldataPtr, srcDataIdx);
+
+				auto calldataSize = ext.calldatasize();
+				// remaining data bytes:
+				auto remDataSize = builder.CreateSub(calldataSize, srcDataIdx);
+				auto remSizeNegative = builder.CreateICmpSLT(remDataSize, zero256);
+				auto bytesToCopy = builder.CreateSelect(remSizeNegative, zero256, remDataSize);
+
+				builder.CreateMemCpy(destPtr, srcPtr, bytesToCopy, 0);
+
+				break;
+			}
+
 			case Instruction::CALLDATALOAD:
 			{
 				auto index = stack.pop();
diff --git a/evmcc/Ext.cpp b/evmcc/Ext.cpp
index 1d309947d..bb2a54870 100644
--- a/evmcc/Ext.cpp
+++ b/evmcc/Ext.cpp
@@ -14,7 +14,6 @@ using llvm::types::i;
 using Linkage = llvm::GlobalValue::LinkageTypes;
 using dev::h256;
 using dev::u256;
-
 namespace evmcc
 {
 
@@ -70,7 +69,7 @@ Ext::Ext(llvm::IRBuilder<>& _builder, llvm::Module* module)
 		i256Ty,	 // i256 number;
 		i256Ty,	 // i256 difficulty;
 		i256Ty,	 // i256 gaslimit;
-		//m_builder.getInt8PtrTy()
+		m_builder.getInt8PtrTy() // byte* calldata
 	};
 	auto extDataTy = StructType::create(elements, "ext.Data");
 
@@ -125,6 +124,7 @@ Value* Ext::timestamp() { return getDataElem(8, "timestamp"); }
 Value* Ext::number() { return getDataElem(9, "number"); }
 Value* Ext::difficulty() { return getDataElem(10, "difficulty"); }
 Value* Ext::gaslimit() { return getDataElem(11, "gaslimit"); }
+Value* Ext::calldata() { return getDataElem(12, "calldata"); }
 
 Value* Ext::calldataload(Value* _index)
 {
@@ -218,7 +218,7 @@ EXPORT void ext_init(ExtData* _extData)
 	_extData->number = eth2llvm(ext.currentBlock.number);
 	_extData->difficulty = eth2llvm(ext.currentBlock.difficulty);
 	_extData->gaslimit = eth2llvm(ext.currentBlock.gasLimit);
-	//_extData->calldata = ext.data.data();
+	_extData->calldata = ext.data.data();
 }
 
 EXPORT void ext_store(i256* _index, i256* _value)
diff --git a/evmcc/Ext.h b/evmcc/Ext.h
index 302991854..5c683ffdf 100644
--- a/evmcc/Ext.h
+++ b/evmcc/Ext.h
@@ -31,6 +31,7 @@ public:
 	llvm::Value* number();
 	llvm::Value* difficulty();
 	llvm::Value* gaslimit();
+	llvm::Value* calldata();
 
 	llvm::Value* balance(llvm::Value* _address);
 	void suicide(llvm::Value* _address);
diff --git a/evmcc/Memory.cpp b/evmcc/Memory.cpp
index 4d4a34928..0098ed1f9 100644
--- a/evmcc/Memory.cpp
+++ b/evmcc/Memory.cpp
@@ -126,6 +126,11 @@ void Memory::storeByte(llvm::Value* _addr, llvm::Value* _word)
 	dump(0);
 }
 
+llvm::Value* Memory::getData()
+{
+	return m_builder.CreateLoad(m_data);
+}
+
 llvm::Value* Memory::getSize()
 {
 	return m_builder.CreateLoad(m_size);
diff --git a/evmcc/Memory.h b/evmcc/Memory.h
index c01bd6ef8..8b22294d7 100644
--- a/evmcc/Memory.h
+++ b/evmcc/Memory.h
@@ -18,6 +18,7 @@ public:
 	llvm::Value* loadWord(llvm::Value* _addr);
 	void storeWord(llvm::Value* _addr, llvm::Value* _word);
 	void storeByte(llvm::Value* _addr, llvm::Value* _byte);
+	llvm::Value* getData();
 	llvm::Value* getSize();
 
 	void registerReturnData(llvm::Value* _index, llvm::Value* _size);