Materialize all constant operands on the stack in the non-optimizing compiler.

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
diff --git a/runtime/vm/flow_graph_compiler_x64.cc b/runtime/vm/flow_graph_compiler_x64.cc
index 3cec293e35334633456009fc653ded297c13bf6d..2eeef3bf3c1c8ac57d6aceb73f9222fe02c0a88f 100644
--- a/runtime/vm/flow_graph_compiler_x64.cc
+++ b/runtime/vm/flow_graph_compiler_x64.cc
@@ -1226,17 +1226,6 @@ void FlowGraphCompiler::VisitBind(BindInstr* instr) {
 void FlowGraphCompiler::VisitReturn(ReturnInstr* instr) {
   LoadValue(RAX, instr->value());
 
-#ifdef DEBUG

[Kevin Millikin (Google), 2012/04/30 14:54:53]

This assert doesn't work anymore because we can have un-popped expression values
on the stack when we return.  Example:

try {
  return 0;
} finally {
  return 1;
}

The value of 0 is sitting on the stack at the return from the finally.  (It
didn't really work before either).

We can reintroduce it when (if) we add stack height tracking and assert the
expected height.

[srdjan, 2012/05/01 00:56:10]

This assert code is/was essential for tracking/locating bugs so far (catches
bugs that otherwise wold go unnoticed). There is difference between what we
track and what the reality is.

Is there a way that we could keep it? Maybe disable it temporarily for now?

-  // Check that the entry stack size matches the exit stack size.
-  __ movq(R10, RBP);
-  __ subq(R10, RSP);
-  __ cmpq(R10, Immediate(StackSize() * kWordSize));
-  Label stack_ok;
-  __ j(EQUAL, &stack_ok, Assembler::kNearJump);
-  __ Stop("Exit stack size does not match the entry stack size.");
-  __ Bind(&stack_ok);
-#endif  // DEBUG.
-
   if (FLAG_trace_functions) {
     __ pushq(RAX);  // Preserve result.
     const Function& function =