Subzero: Use more "= default;" for ctors and dtors.

Look for "() override {}" and "() final {}" patterns.

Don't touch IceTargetLoweringX8632.* to spare a refactoring in
progress.

BUG= none
R=jpp@chromium.org

Review URL: https://codereview.chromium.org/1201023002
diff --git a/src/IceCompileServer.h b/src/IceCompileServer.h
index 497810a..b5093df 100644
--- a/src/IceCompileServer.h
+++ b/src/IceCompileServer.h
@@ -69,7 +69,7 @@
   CLCompileServer(Compiler &Comp, int argc, char **argv)
       : CompileServer(Comp), argc(argc), argv(argv) {}
 
-  ~CLCompileServer() final {}
+  ~CLCompileServer() final = default;
 
   void run() final;
 
diff --git a/src/IceTargetLoweringARM32.h b/src/IceTargetLoweringARM32.h
index b7efac3..fdb025f 100644
--- a/src/IceTargetLoweringARM32.h
+++ b/src/IceTargetLoweringARM32.h
@@ -341,7 +341,7 @@
   };
 
 private:
-  ~TargetARM32() override {}
+  ~TargetARM32() override = default;
 };
 
 class TargetDataARM32 final : public TargetDataLowering {
@@ -362,7 +362,7 @@
   explicit TargetDataARM32(GlobalContext *Ctx);
 
 private:
-  ~TargetDataARM32() override {}
+  ~TargetDataARM32() override = default;
   template <typename T> static void emitConstantPool(GlobalContext *Ctx);
 };
 
diff --git a/src/IceTargetLoweringMIPS32.h b/src/IceTargetLoweringMIPS32.h
index 5383f38..eb4a9fd 100644
--- a/src/IceTargetLoweringMIPS32.h
+++ b/src/IceTargetLoweringMIPS32.h
@@ -124,7 +124,7 @@
   static IceString RegNames[];
 
 private:
-  ~TargetMIPS32() override {}
+  ~TargetMIPS32() override = default;
 };
 
 class TargetDataMIPS32 final : public TargetDataLowering {
@@ -145,7 +145,7 @@
   explicit TargetDataMIPS32(GlobalContext *Ctx);
 
 private:
-  ~TargetDataMIPS32() override {}
+  ~TargetDataMIPS32() override = default;
   template <typename T> static void emitConstantPool(GlobalContext *Ctx);
 };
 
diff --git a/src/PNaClTranslator.cpp b/src/PNaClTranslator.cpp
index 11a1f27..a9f60b8 100644
--- a/src/PNaClTranslator.cpp
+++ b/src/PNaClTranslator.cpp
@@ -168,7 +168,7 @@
         ErrorStatus(ErrorStatus),
         VariableDeclarations(new Ice::VariableDeclarationList()) {}
 
-  ~TopLevelParser() override {}
+  ~TopLevelParser() override = default;
 
   Ice::Translator &getTranslator() const { return Translator; }
 
@@ -728,7 +728,7 @@
       : BlockParserBaseClass(BlockID, EnclosingParser),
         Timer(Ice::TimerStack::TT_parseTypes, getTranslator().getContext()) {}
 
-  ~TypesParser() override {}
+  ~TypesParser() override = default;
 
 private:
   Ice::TimerMarker Timer;
@@ -909,7 +909,7 @@
             Ice::VariableDeclaration::create(getTranslator().getContext())),
         CurGlobalVar(DummyGlobalVar) {}
 
-  ~GlobalsParser() final {}
+  ~GlobalsParser() final = default;
 
   const char *getBlockName() const override { return "globals"; }
 
@@ -1063,7 +1063,7 @@
   ValuesymtabParser(unsigned BlockID, BlockParserBaseClass *EnclosingParser)
       : BlockParserBaseClass(BlockID, EnclosingParser) {}
 
-  ~ValuesymtabParser() override {}
+  ~ValuesymtabParser() override = default;
 
   const char *getBlockName() const override { return "valuesymtab"; }
 
@@ -1187,7 +1187,7 @@
     return ParserResult;
   }
 
-  ~FunctionParser() final {}
+  ~FunctionParser() final = default;
 
   const char *getBlockName() const override { return "function"; }
 
@@ -2606,7 +2606,7 @@
         Timer(Ice::TimerStack::TT_parseConstants, getTranslator().getContext()),
         FuncParser(FuncParser) {}
 
-  ~ConstantsParser() override {}
+  ~ConstantsParser() override = default;
 
   const char *getBlockName() const override { return "constants"; }
 
@@ -2821,7 +2821,7 @@
         Timer(Ice::TimerStack::TT_parseModule,
               Context->getTranslator().getContext()) {}
 
-  ~ModuleParser() override {}
+  ~ModuleParser() override = default;
 
   const char *getBlockName() const override { return "module"; }
 
@@ -2861,7 +2861,7 @@
         Timer(Ice::TimerStack::TT_parseModuleValuesymtabs,
               getTranslator().getContext()) {}
 
-  ~ModuleValuesymtabParser() override {}
+  ~ModuleValuesymtabParser() override = default;
 
 private:
   Ice::TimerMarker Timer;