Subzero: Add -Wshadow to the build.

src/IceRegAlloc.cpp

Index: src/IceRegAlloc.cpp
diff --git a/src/IceRegAlloc.cpp b/src/IceRegAlloc.cpp
index 1478b0fd1b13a8c943d4135b56b5c4067ff2b7d3..ee13f86541fda56a619ea8f7ce107c047a8e41cc 100644
--- a/src/IceRegAlloc.cpp
+++ b/src/IceRegAlloc.cpp
@@ -177,8 +177,8 @@ void LinearScan::initForInfOnly() {
       }
       for (SizeT I = 0; I < Inst.getSrcSize(); ++I) {
         Operand *Src = Inst.getSrc(I);
-        SizeT NumVars = Src->getNumVars();
-        for (SizeT J = 0; J < NumVars; ++J) {
+        SizeT NVars = Src->getNumVars();
+        for (SizeT J = 0; J < NVars; ++J) {
           const Variable *Var = Src->getVar(J);
           if (Var->hasReg() || Var->getWeight().isInf())
             LREnd[Var->getIndex()] = Inst.getNumber();
@@ -674,7 +674,7 @@ void LinearScan::scan(const llvm::SmallBitVector &RegMaskFull,
         }
       }
     }
-    dump(Func);
+    dump();
   }
   // Move anything Active or Inactive to Handled for easier handling.
   for (Variable *I : Active)
@@ -683,7 +683,7 @@ void LinearScan::scan(const llvm::SmallBitVector &RegMaskFull,
   for (Variable *I : Inactive)
     Handled.push_back(I);
   Inactive.clear();
-  dump(Func);
+  dump();
 
   llvm::SmallVector<int32_t, REGS_SIZE> Permutation(NumRegisters);
   if (Randomized) {
@@ -735,7 +735,7 @@ void LinearScan::scan(const llvm::SmallBitVector &RegMaskFull,
 
 // ======================== Dump routines ======================== //
 
-void LinearScan::dump(Cfg *Func) const {
+void LinearScan::dump() const {
   if (!BuildDefs::dump())
     return;
   if (!Func->isVerbose(IceV_LinearScan))