From 080cf20f84db00418173e6b2db74c2b50291b4a7 Mon Sep 17 00:00:00 2001
From: artur-zawlocki <artur.zawlocki@gmail.com>
Date: Tue, 21 Oct 2014 15:53:51 +0100
Subject: [PATCH] Handling pop() from the empty EVM stack. [#80895676]

---
 libevmjit/Compiler.cpp | 11 +++++++----
 libevmjit/Stack.cpp    |  8 ++++++++
 libevmjit/Type.h       |  1 +
 libevmjit/VM.cpp       |  2 ++
 4 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/libevmjit/Compiler.cpp b/libevmjit/Compiler.cpp
index a887974137..640561ad97 100644
--- a/libevmjit/Compiler.cpp
+++ b/libevmjit/Compiler.cpp
@@ -925,6 +925,9 @@ void Compiler::linkBasicBlocks(Stack& stack)
 		{
 			auto& bbInfo = pair.second;
 
+			if (bbInfo.predecessors.empty())
+				bbInfo.inputItems = 0; // no consequences for other blocks, so leave valuesChanged false
+
 			for (auto predInfo : bbInfo.predecessors)
 			{
 				if (predInfo->outputItems < bbInfo.inputItems)
@@ -996,11 +999,11 @@ void Compiler::dumpBasicBlockGraph(std::ostream& out)
 
 	std::vector<BasicBlock*> blocks;
 	for (auto& pair : this->basicBlocks)
-	{
 		blocks.push_back(&pair.second);
-	}
-	blocks.push_back(m_jumpTableBlock.get());
-	blocks.push_back(m_badJumpBlock.get());
+	if (m_jumpTableBlock.get())
+		blocks.push_back(m_jumpTableBlock.get());
+	if (m_badJumpBlock.get())
+		blocks.push_back(m_badJumpBlock.get());
 
 	// Output nodes
 	for (auto bb : blocks)
diff --git a/libevmjit/Stack.cpp b/libevmjit/Stack.cpp
index 772e6255be..ce7d09471b 100644
--- a/libevmjit/Stack.cpp
+++ b/libevmjit/Stack.cpp
@@ -1,5 +1,8 @@
 #include "Stack.h"
 #include "Runtime.h"
+#include "Type.h"
+
+#include <csetjmp>
 
 #include <llvm/IR/Function.h>
 #include <llvm/IR/TypeBuilder.h>
@@ -51,9 +54,14 @@ extern "C"
 
 using namespace dev::eth::jit;
 
+extern std::jmp_buf* rt_jmpBuf;
+
 EXPORT void stack_pop(i256* _ret)
 {
 	auto& stack = Runtime::getStack();
+	if (stack.size() == 0)
+		longjmp(*rt_jmpBuf, static_cast<uint64_t>(ReturnCode::StackTooSmall));
+
 	assert(stack.size() > 0);
 	*_ret = stack.back();
 	stack.pop_back();
diff --git a/libevmjit/Type.h b/libevmjit/Type.h
index 06907b7df6..a03bfac381 100644
--- a/libevmjit/Type.h
+++ b/libevmjit/Type.h
@@ -39,6 +39,7 @@ enum class ReturnCode
 
 	BadJumpDestination = 101,
 	OutOfGas = 102,
+	StackTooSmall = 103
 };
 
 struct Constant
diff --git a/libevmjit/VM.cpp b/libevmjit/VM.cpp
index 6b8b3e38bc..16011241ec 100644
--- a/libevmjit/VM.cpp
+++ b/libevmjit/VM.cpp
@@ -26,6 +26,8 @@ bytes VM::go(ExtVMFace& _ext)
 		BOOST_THROW_EXCEPTION(BadJumpDestination());
 	case 102:
 		BOOST_THROW_EXCEPTION(OutOfGas());
+	case 103:
+		BOOST_THROW_EXCEPTION(StackTooSmall(1,0));
 	}
 
 	return std::move(engine.returnData);