Implements include/exclude register lists for translation.

src/IceClFlags.h

Index: src/IceClFlags.h
diff --git a/src/IceClFlags.h b/src/IceClFlags.h
index d89186c886e3502746686a6ddad6707664b4ed44..47c7b780fac0f0db44b6967f69b9e30a378983e1 100644
--- a/src/IceClFlags.h
+++ b/src/IceClFlags.h
@@ -115,6 +115,16 @@ public:
   /// Set ClFlags::EnableBlockProfile to a new value
   void setEnableBlockProfile(bool NewValue) { EnableBlockProfile = NewValue; }
 
+  /// Get the restricted list of registers to use, for corresponding register
+  /// classes, in register allocation.
+  const std::unordered_set<IceString> &getUseRestrictedRegisters() const {
+    return UseRestrictedRegisters;
+  }
+  void clearUseRestrictedRegisters() { UseRestrictedRegisters.clear(); }
+  void insertUseRestrictedRegister(const IceString &Str) {
+    UseRestrictedRegisters.insert(Str);
+  }
+
   /// Get the value of ClFlags::ForceMemIntrinOpt
   bool getForceMemIntrinOpt() const { return ForceMemIntrinOpt; }
   /// Set ClFlags::ForceMemIntrinOpt to a new value
@@ -186,6 +196,15 @@ public:
   /// Set ClFlags::UseNonsfi to a new value
   void setUseNonsfi(bool NewValue) { UseNonsfi = NewValue; }
 
+  /// Get the list of registers exluded in register allocation.
+  const std::unordered_set<IceString> &getExcludedRegisters() const {
+    return ExcludedRegisters;
+  }
+  void clearExcludedRegisters() { ExcludedRegisters.clear(); }
+  void insertExcludedRegister(const IceString &Str) {
+    ExcludedRegisters.insert(Str);
+  }
+
   /// Get the value of ClFlags::UseSandboxing
   bool getUseSandboxing() const { return UseSandboxing; }
   /// Set ClFlags::UseSandboxing to a new value
@@ -390,6 +409,8 @@ private:
   bool DumpStats;
   /// see anonymous_namespace{IceClFlags.cpp}::EnableBlockProfile
   bool EnableBlockProfile;
+  /// see anonymous_namespace{IceClFlags.cpp}::ExcludedRegisters;
+  std::unordered_set<IceString> ExcludedRegisters;
   /// see anonymous_namespace{IceClFlags.cpp}::ForceMemIntrinOpt
   bool ForceMemIntrinOpt;
   /// see anonymous_namespace{IceClFlags.cpp}::FunctionSections
@@ -422,6 +443,8 @@ private:
   bool TimeEachFunction;
   /// see anonymous_namespace{IceClFlags.cpp}::UseNonsfi
   bool UseNonsfi;
+  /// see anonymous_namespace{IceClFlags.cpp}::UseRegistrictedRegisters;
+  std::unordered_set<IceString> UseRestrictedRegisters;
   /// see anonymous_namespace{IceClFlags.cpp}::UseSandboxing
   bool UseSandboxing;
   /// see anonymous_namespace{IceClFlags.cpp}::OLevel