Allow the creation of human-friendly ASTDumper to arbitrary output stream

[whisperity]

Summary

ASTPrinter allows setting the ouput to any O-Stream, but that printer creates source-code-like syntax (and is also marked with a FIXME). The nice, colourful, mostly human-readable ASTDumper only works on the standard output, which is not feasible in case a user wants to see the AST of a file through a code navigation/comprehension tool.

This small addition of an overload solves generating a nice colourful AST block for the users of a tool I'm working on, CodeCompass, as opposed to having to duplicate the behaviour of definitions that only exist in the anonymous namespace of implementation TUs related to this module.

[alexfh]

Looks good to me. One optional comment.

include/clang/Frontend/ASTConsumers.h

39–41

With just three users of the old API it might make sense to just add a parameter to it and update the callers instead of adding another override.

[whisperity]

• Overload removed, now only one CreateASTDumper function remains.
• Updated the call sites of this function to use this call.

[whisperity]

@alexfh I have updated the patch. I don't have commit rights, so if you think this is good to go, could you please commit for me?

[alexfh]

Another couple of nits.

docs/HowToSetupToolingForLLVM.rst

136 ↗

(On Diff #141194)

Please add an argument comment for nullptr, e.g.

return clang::CreateASTDumper(/*OS=*/nullptr, ...);

or maybe

return clang::CreateASTDumper(nullptr /*dump to stderr*/, ...);

Same in the actual callers below.

include/clang/Frontend/ASTConsumers.h

40

Add "When OS is nullptr, dumps AST to stderr."

[whisperity]

Added comments on what nullptr means at call sites.

[whisperity]

It is also std-out (llvm::outs()) in case of nullptr and not std-err.

[alexfh]

LG. I'll commit the patch for you.

include/clang/Frontend/ASTConsumers.h

 // original C code.  The output is intended to be in a format such that
 // clang could re-parse the output back into the same AST, but the
 // implementation is still incomplete.
 std::unique_ptr<ASTConsumer> CreateASTPrinter(std::unique_ptr<raw_ostream> OS,
                                               StringRef FilterString);
 
 // AST dumper: dumps the raw AST in human-readable form to stderr; this is
 // intended for debugging.
 std::unique_ptr<ASTConsumer> CreateASTDumper(StringRef FilterString,
                                              bool DumpDecls, bool Deserialize,
                                              bool DumpLookups);
 
+// AST dumper: dumps the raw AST in human-readable form to the given output
+// stream.
+std::unique_ptr<ASTConsumer> CreateASTDumper(std::unique_ptr<raw_ostream> OS,
+                                             StringRef FilterString,
+                                             bool DumpDecls, bool Deserialize,
+                                             bool DumpLookups);
+
 // AST Decl node lister: prints qualified names of all filterable AST Decl
 // nodes.
 std::unique_ptr<ASTConsumer> CreateASTDeclNodeLister();
 
 // Graphical AST viewer: for each function definition, creates a graph of
 // the AST and displays it with the graph viewer "dotty".  Also outputs
 // function declarations to stderr.
 std::unique_ptr<ASTConsumer> CreateASTViewer();
 
 // DeclContext printer: prints out the DeclContext tree in human-readable form
 // to stderr; this is intended for debugging.
 std::unique_ptr<ASTConsumer> CreateDeclContextPrinter();
 
 } // end clang namespace
 
 #endif

lib/Frontend/ASTConsumers.cpp

clang::CreateASTPrinter(std::unique_ptr<raw_ostream> Out,
   return llvm::make_unique<ASTPrinter>(std::move(Out), ASTPrinter::Print,
                                        FilterString);
 }
 
 std::unique_ptr<ASTConsumer> clang::CreateASTDumper(StringRef FilterString,
                                                     bool DumpDecls,
                                                     bool Deserialize,
                                                     bool DumpLookups) {
+  return CreateASTDumper(nullptr, FilterString,
+                         DumpDecls, Deserialize, DumpLookups);
+}
+
+std::unique_ptr<ASTConsumer>
+clang::CreateASTDumper(std::unique_ptr<raw_ostream> Out,
+                       StringRef FilterString,
+                       bool DumpDecls,
+                       bool Deserialize,
+                       bool DumpLookups) {
   assert((DumpDecls || Deserialize || DumpLookups) && "nothing to dump");
-  return llvm::make_unique<ASTPrinter>(nullptr,
+  return llvm::make_unique<ASTPrinter>(std::move(Out),
                                        Deserialize ? ASTPrinter::DumpFull :
                                        DumpDecls ? ASTPrinter::Dump :
                                        ASTPrinter::None,
                                        FilterString, DumpLookups);
 }
 
 std::unique_ptr<ASTConsumer> clang::CreateASTDeclNodeLister() {
   return llvm::make_unique<ASTDeclNodeLister>(nullptr);