Subzero: Randomly insert nops.

src/IceInstX8632.cpp

Index: src/IceInstX8632.cpp
diff --git a/src/IceInstX8632.cpp b/src/IceInstX8632.cpp
index 1f7508bc413a6f1d26850b97d51188548978bc81..13be72d6c37316af18d179a4d23abafe0bf815cb 100644
--- a/src/IceInstX8632.cpp
+++ b/src/IceInstX8632.cpp
@@ -256,6 +256,9 @@ InstX8632Movzx::InstX8632Movzx(Cfg *Func, Variable *Dest, Operand *Source)
   addSource(Source);
 }
 
+InstX8632Nop::InstX8632Nop(Cfg *Func, SizeT Length)
+    : InstX8632(Func, InstX8632::Nop, 0, NULL), Length(Length) {}
+
 InstX8632Fld::InstX8632Fld(Cfg *Func, Operand *Src)
     : InstX8632(Func, InstX8632::Fld, 1, NULL) {
   addSource(Src);
@@ -1123,6 +1126,20 @@ void InstX8632Movzx::dump(const Cfg *Func) const {
   dumpSources(Func);
 }
 
+void InstX8632Nop::emit(const Cfg *Func) const {
+  Ostream &Str = Func->getContext()->getStrEmit();
+  assert(Length);
+  // TODO: When an assembler is used, use the recommended opcodes in the
+  // Intel manual to emit nop instructions based on the length.
+  Str << "\tnop\t# length = " << Length << (Length > 1 ? " bytes" : " byte")
+      << "\n";
+}
+
+void InstX8632Nop::dump(const Cfg *Func) const {
+  Ostream &Str = Func->getContext()->getStrDump();
+  Str << "nop (length = " << Length << (Length > 1 ? " bytes)" : " byte)");
+}
+
 void InstX8632Fld::emit(const Cfg *Func) const {
   Ostream &Str = Func->getContext()->getStrEmit();
   assert(getSrcSize() == 1);