Add a new hidden option to the interpreter to cause it to print
out every volatile load and store.  This is useful for tracking 
down insane volatile memory bugs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53241 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/Interpreter/Execution.cpp b/lib/ExecutionEngine/Interpreter/Execution.cpp
index d05e8d0..29837ff 100644
--- a/lib/ExecutionEngine/Interpreter/Execution.cpp
+++ b/lib/ExecutionEngine/Interpreter/Execution.cpp
@@ -21,6 +21,7 @@
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/MathExtras.h"
 #include <algorithm>
@@ -31,6 +32,9 @@
 STATISTIC(NumDynamicInsts, "Number of dynamic instructions executed");
 static Interpreter *TheEE = 0;
 
+static cl::opt<bool> PrintVolatile("interpreter-print-volatile", cl::Hidden,
+          cl::desc("make the interpreter print every volatile load and store"));
+
 //===----------------------------------------------------------------------===//
 //                     Various Helper Functions
 //===----------------------------------------------------------------------===//
@@ -830,6 +834,8 @@
   GenericValue Result;
   LoadValueFromMemory(Result, Ptr, I.getType());
   SetValue(&I, Result, SF);
+  if (I.isVolatile() && PrintVolatile)
+    cerr << "Volatile load " << I;
 }
 
 void Interpreter::visitStoreInst(StoreInst &I) {
@@ -838,6 +844,8 @@
   GenericValue SRC = getOperandValue(I.getPointerOperand(), SF);
   StoreValueToMemory(Val, (GenericValue *)GVTOP(SRC),
                      I.getOperand(0)->getType());
+  if (I.isVolatile() && PrintVolatile)
+    cerr << "Volatile store: " << I;
 }
 
 //===----------------------------------------------------------------------===//