Adjust stack offloading params. Enable only for clang compiler.

libethereum/ExtVM.cpp

@@ -37,14 +37,17 @@ static size_t const c_singleExecutionStackSize =
 #ifdef NDEBUG
 	12 * 1024;
 #else
-	64 * 1024;
+	33 * 1024;
 #endif
 
 /// Standard OSX thread stack limit. Should be reasonable for other platforms too.
 static size_t const c_defaultStackSize = 512 * 1024;
 
+/// Stack overhead prior to allocation.
+static size_t const c_entryOverhead = 128 * 1024;
+
 /// On what depth execution should be offloaded to additional separated stack space.
-static unsigned const c_offloadPoint = c_defaultStackSize / c_singleExecutionStackSize;
+static unsigned const c_offloadPoint = (c_defaultStackSize - c_entryOverhead) / c_singleExecutionStackSize;
 
 void goOnOffloadedStack(Executive& _e, OnOpFunc const& _onOp)
 {
@@ -75,7 +78,7 @@ void go(unsigned _depth, Executive& _e, OnOpFunc const& _onOp)
 	// Current stack is too small to handle more CALL/CREATE executions.
 	// It needs to be done only once as newly allocated stack space it enough to handle
 	// the rest of the calls up to the depth limit (c_depthLimit).
-#if __GNUC__
+#if __clang__ // Enabled for clang only as the problem affects OSX
 	if (_depth == c_offloadPoint)
 		goOnOffloadedStack(_e, _onOp);
 	else