[clang][Frontend] Add overload to ASTPrinter that doesn't own output stream (llvm#142163)

We're planning on using the ASTPrinter in LLDB for AST dumping. But it
currently takes the output stream via `unique_ptr`. In LLDB we don't
have the output stream available in this form and instead it would be
convenient if we could just pass a reference to the stream.

This patch adds that overload.

(cherry picked from commit 41d6343)

Author: Michael137

clang/include/clang/Frontend/ASTConsumers.h

@@ -35,6 +35,11 @@ CreateASTDumper(std::unique_ptr<raw_ostream> OS, StringRef FilterString,
                 bool DumpDecls, bool Deserialize, bool DumpLookups,
                 bool DumpDeclTypes, ASTDumpOutputFormat Format);
 
+std::unique_ptr<ASTConsumer>
+CreateASTDumper(raw_ostream &OS, StringRef FilterString, bool DumpDecls,
+                bool Deserialize, bool DumpLookups, bool DumpDeclTypes,
+                ASTDumpOutputFormat Format);
+
 // AST Decl node lister: prints qualified names of all filterable AST Decl
 // nodes.
 std::unique_ptr<ASTConsumer> CreateASTDeclNodeLister();

clang/lib/Frontend/ASTConsumers.cpp

@@ -41,6 +41,13 @@ namespace {
           OutputKind(K), OutputFormat(Format), FilterString(FilterString),
           DumpLookups(DumpLookups), DumpDeclTypes(DumpDeclTypes) {}
 
+    ASTPrinter(raw_ostream &Out, Kind K, ASTDumpOutputFormat Format,
+               StringRef FilterString, bool DumpLookups = false,
+               bool DumpDeclTypes = false)
+        : Out(Out), OwnedOut(nullptr), OutputKind(K), OutputFormat(Format),
+          FilterString(FilterString), DumpLookups(DumpLookups),
+          DumpDeclTypes(DumpDeclTypes) {}
+
     void HandleTranslationUnit(ASTContext &Context) override {
       TranslationUnitDecl *D = Context.getTranslationUnitDecl();
 
@@ -175,6 +182,19 @@ clang::CreateASTDumper(std::unique_ptr<raw_ostream> Out, StringRef FilterString,
       Format, FilterString, DumpLookups, DumpDeclTypes);
 }
 
+std::unique_ptr<ASTConsumer>
+clang::CreateASTDumper(raw_ostream &Out, StringRef FilterString, bool DumpDecls,
+                       bool Deserialize, bool DumpLookups, bool DumpDeclTypes,
+                       ASTDumpOutputFormat Format) {
+  assert((DumpDecls || Deserialize || DumpLookups) && "nothing to dump");
+  return std::make_unique<ASTPrinter>(Out,
+                                      Deserialize ? ASTPrinter::DumpFull
+                                      : DumpDecls ? ASTPrinter::Dump
+                                                  : ASTPrinter::None,
+                                      Format, FilterString, DumpLookups,
+                                      DumpDeclTypes);
+}
+
 std::unique_ptr<ASTConsumer> clang::CreateASTDeclNodeLister() {
   return std::make_unique<ASTDeclNodeLister>(nullptr);
 }