From d5f7de4a2ea45f78b614857182aed22a4442aa38 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Bylica?= <pawel.bylica@imapp.pl>
Date: Mon, 13 Oct 2014 12:50:23 +0200
Subject: [PATCH] Always commit cost blocks

[#79942174]
---
 evmcc/Compiler.cpp |  4 +++-
 evmcc/GasMeter.cpp | 18 +++++++++++++-----
 evmcc/GasMeter.h   |  6 +++++-
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/evmcc/Compiler.cpp b/evmcc/Compiler.cpp
index e532ce9f5..1fc4ef6a1 100644
--- a/evmcc/Compiler.cpp
+++ b/evmcc/Compiler.cpp
@@ -213,7 +213,7 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 		{
 			auto inst = static_cast<Instruction>(bytecode[currentPC]);
 
-			gasMeter.check(inst);
+			gasMeter.count(inst);
 
 			switch (inst)
 			{
@@ -819,6 +819,8 @@ std::unique_ptr<llvm::Module> Compiler::compile(const dev::bytes& bytecode)
 			}
 		}
 
+		gasMeter.commitCostBlock();
+
 		if (!builder.GetInsertBlock()->getTerminator())	// If block not terminated
 		{
 			if (basicBlock.end() == bytecode.size())
diff --git a/evmcc/GasMeter.cpp b/evmcc/GasMeter.cpp
index fd68b9d40..7ba822e4a 100644
--- a/evmcc/GasMeter.cpp
+++ b/evmcc/GasMeter.cpp
@@ -97,22 +97,30 @@ GasMeter::GasMeter(llvm::IRBuilder<>& _builder, llvm::Module* _module):
 	m_builder.SetInsertPoint(bb, pt);
 }
 
-void GasMeter::check(Instruction _inst)
+void GasMeter::count(Instruction _inst)
 {
 	if (!m_checkCall)
 	{
 		// Create gas check call with mocked block cost at begining of current cost-block
-		m_checkCall = m_builder.CreateCall(m_gasCheckFunc, m_builder.getIntN(256, 0));
+		m_checkCall = m_builder.CreateCall(m_gasCheckFunc, llvm::UndefValue::get(Type::i256));
 	}
 	
 	m_blockCost += getStepCost(_inst);
 
 	if (isCostBlockEnd(_inst))
-	{		
-		m_checkCall->setArgOperand(0, m_builder.getIntN(256, m_blockCost)); // Update block cost in gas check call		
+		commitCostBlock();
+}
+
+void GasMeter::commitCostBlock()
+{
+	// If any uncommited block
+	if (m_checkCall)
+	{
+		m_checkCall->setArgOperand(0, m_builder.getIntN(256, m_blockCost)); // Update block cost in gas check call
 		m_checkCall = nullptr; // End cost-block
 		m_blockCost = 0;
-	}	
+	}
+	assert(m_blockCost == 0);
 }
 
 void GasMeter::checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilder<>& _builder)
diff --git a/evmcc/GasMeter.h b/evmcc/GasMeter.h
index 73f0d6e1c..38f780ca5 100644
--- a/evmcc/GasMeter.h
+++ b/evmcc/GasMeter.h
@@ -16,7 +16,11 @@ public:
 	GasMeter(const GasMeter&) = delete;
 	void operator=(GasMeter) = delete;
 
-	void check(dev::eth::Instruction _inst);
+	/// Count step cost of instruction
+	void count(dev::eth::Instruction _inst);
+
+	/// Finalize cost block by checking gas needed for the block before the block
+	void commitCostBlock();
 
 	/// Generate code that checks the cost of additional memory used by program
 	void checkMemory(llvm::Value* _additionalMemoryInWords, llvm::IRBuilder<>& _builder);