[clang] Implement CompilerInvocation copy assignment

[jansvoboda11]

Summary

This patch implements the copy assignment for CompilerInvocation.

Eventually, the deep-copy operation will be moved into a clone() method (D100460), but until then, this is necessary for basic ergonomics.

Depends on D100455.

[Bigcheese]

I think this is fine given that we already have a copy constructor with deep copy semantics.

lgtm

clang/include/clang/Frontend/CompilerInvocation.h

public:
   /// Options controlling the preprocessor (aside from \#include handling).
   std::shared_ptr<PreprocessorOptions> PreprocessorOpts;
 
   /// Options controlling the static analyzer.
   AnalyzerOptionsRef AnalyzerOpts;
 
   CompilerInvocationRefBase();
   CompilerInvocationRefBase(const CompilerInvocationRefBase &X);
-  CompilerInvocationRefBase &
-  operator=(const CompilerInvocationRefBase &) = delete;
+  CompilerInvocationRefBase(CompilerInvocationRefBase &&X);
+  CompilerInvocationRefBase &operator=(CompilerInvocationRefBase X);
+  CompilerInvocationRefBase &operator=(CompilerInvocationRefBase &&X);
   ~CompilerInvocationRefBase();
 
   LangOptions *getLangOpts() { return LangOpts.get(); }
   const LangOptions *getLangOpts() const { return LangOpts.get(); }
 
   TargetOptions &getTargetOpts() { return *TargetOpts.get(); }
   const TargetOptions &getTargetOpts() const { return *TargetOpts.get(); }
 

clang/lib/Frontend/CompilerInvocation.cpp

CompilerInvocationRefBase::CompilerInvocationRefBase(
     const CompilerInvocationRefBase &X)
     : LangOpts(new LangOptions(*X.getLangOpts())),
       TargetOpts(new TargetOptions(X.getTargetOpts())),
       DiagnosticOpts(new DiagnosticOptions(X.getDiagnosticOpts())),
       HeaderSearchOpts(new HeaderSearchOptions(X.getHeaderSearchOpts())),
       PreprocessorOpts(new PreprocessorOptions(X.getPreprocessorOpts())),
       AnalyzerOpts(new AnalyzerOptions(*X.getAnalyzerOpts())) {}
 
+CompilerInvocationRefBase::CompilerInvocationRefBase(
+    CompilerInvocationRefBase &&X) = default;
+
+CompilerInvocationRefBase &
+CompilerInvocationRefBase::operator=(CompilerInvocationRefBase X) {
+  LangOpts.swap(X.LangOpts);
+  TargetOpts.swap(X.TargetOpts);
+  DiagnosticOpts.swap(X.DiagnosticOpts);
+  HeaderSearchOpts.swap(X.HeaderSearchOpts);
+  PreprocessorOpts.swap(X.PreprocessorOpts);
+  AnalyzerOpts.swap(X.AnalyzerOpts);
+  return *this;
+}
+
+CompilerInvocationRefBase &
+CompilerInvocationRefBase::operator=(CompilerInvocationRefBase &&X) = default;
+
 CompilerInvocationRefBase::~CompilerInvocationRefBase() = default;
 
 //===----------------------------------------------------------------------===//
 // Normalizers
 //===----------------------------------------------------------------------===//
 
 #define SIMPLE_ENUM_VALUE_TABLE
 #include "clang/Driver/Options.inc"

clang/unittests/Frontend/CompilerInvocationTest.cpp

 TEST(ContainsN, Two) {
   const char *Array[] = {"x", "a", "b", "x"};
 
   ASSERT_THAT(Array, Not(ContainsN(StrEq("x"), 0)));
   ASSERT_THAT(Array, Not(ContainsN(StrEq("x"), 1)));
   ASSERT_THAT(Array, ContainsN(StrEq("x"), 2));
 }
 
-// Copy constructor performs a deep copy of reference-counted pointers.
+// Copy constructor/assignment perform deep copy of reference-counted pointers.
 
 TEST(CompilerInvocationTest, DeepCopyConstructor) {
   CompilerInvocation A;
   A.getAnalyzerOpts()->Config["Key"] = "Old";
 
   CompilerInvocation B(A);
   B.getAnalyzerOpts()->Config["Key"] = "New";
 
   ASSERT_EQ(A.getAnalyzerOpts()->Config["Key"], "Old");
 }
 
+TEST(CompilerInvocationTest, DeepCopyAssignment) {
+  CompilerInvocation A;
+  A.getAnalyzerOpts()->Config["Key"] = "Old";
+
+  CompilerInvocation B;
+  B = A;
+  B.getAnalyzerOpts()->Config["Key"] = "New";
+
+  ASSERT_EQ(A.getAnalyzerOpts()->Config["Key"], "Old");
+}
+
 // Boolean option with a keypath that defaults to true.
 // The only flag with a negative spelling can set the keypath to false.
 
 TEST_F(CommandLineTest, BoolOptionDefaultTrueSingleFlagNotPresent) {
   const char *Args[] = {""};
 
   ASSERT_TRUE(CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags));
   ASSERT_TRUE(Invocation.getFrontendOpts().UseTemporary);