Add an LLVM-style dump method to CompilerType for extra convenience during debugging

[aprantl]

Summary

I find myself extracting m_type and and casting it to call dump() on the raw AST type several times per day, so why not make this a little more convenient!

[davide]

This will save me characters typing, thanks!

[davide]

We should also add it to SwiftASTContext downstream.

lldb/include/lldb/Symbol/ClangASTContext.h

   // bytes in the "dst" buffer.
   size_t ConvertStringToFloatValue(lldb::opaque_compiler_type_t type,
                                    const char *s, uint8_t *dst,
                                    size_t dst_size) override;
 
   //----------------------------------------------------------------------
   // Dumping types
   //----------------------------------------------------------------------
+#ifndef NDEBUG
+  /// Convenience LLVM-style dump method for use in the debugger only.
+  /// In contrast to the other \p Dump() methods this directly invokes
+  /// \p clang::QualType::dump().
+  LLVM_DUMP_METHOD void dump(lldb::opaque_compiler_type_t type) const override;
+#endif
+
   void Dump(Stream &s);
 
   void DumpValue(lldb::opaque_compiler_type_t type, ExecutionContext *exe_ctx,
                  Stream *s, lldb::Format format, const DataExtractor &data,
                  lldb::offset_t data_offset, size_t data_byte_size,
                  uint32_t bitfield_bit_size, uint32_t bitfield_bit_offset,
                  bool show_types, bool show_summary, bool verbose,
                  uint32_t depth) override;

lldb/include/lldb/Symbol/CompilerType.h

   // Converts "s" to a floating point value and place resulting floating point
   // bytes in the "dst" buffer.
   size_t ConvertStringToFloatValue(const char *s, uint8_t *dst,
                                    size_t dst_size) const;
 
   //----------------------------------------------------------------------
   // Dumping types
   //----------------------------------------------------------------------
+
+#ifndef NDEBUG
+  /// Convenience LLVM-style dump method for use in the debugger only.
+  /// Don't call this function from actual code.
+  LLVM_DUMP_METHOD void dump() const;
+#endif
+
   void DumpValue(ExecutionContext *exe_ctx, Stream *s, lldb::Format format,
                  const DataExtractor &data, lldb::offset_t data_offset,
                  size_t data_byte_size, uint32_t bitfield_bit_size,
                  uint32_t bitfield_bit_offset, bool show_types,
                  bool show_summary, bool verbose, uint32_t depth);
 
   bool DumpTypeValue(Stream *s, lldb::Format format, const DataExtractor &data,
                      lldb::offset_t data_offset, size_t data_byte_size,

lldb/include/lldb/Symbol/TypeSystem.h

                                            size_t idx);
   virtual llvm::Optional<CompilerType::IntegralTemplateArgument>
   GetIntegralTemplateArgument(lldb::opaque_compiler_type_t type, size_t idx);
 
   //----------------------------------------------------------------------
   // Dumping types
   //----------------------------------------------------------------------
 
+#ifndef NDEBUG
+  /// Convenience LLVM-style dump method for use in the debugger only.
+  LLVM_DUMP_METHOD virtual void
+  dump(lldb::opaque_compiler_type_t type) const = 0;
+#endif
+  
   virtual void DumpValue(lldb::opaque_compiler_type_t type,
                          ExecutionContext *exe_ctx, Stream *s,
                          lldb::Format format, const DataExtractor &data,
                          lldb::offset_t data_offset, size_t data_byte_size,
                          uint32_t bitfield_bit_size,
                          uint32_t bitfield_bit_offset, bool show_types,
                          bool show_summary, bool verbose, uint32_t depth) = 0;
 

lldb/source/Symbol/ClangASTContext.cpp

   return 0;
 }
 
 //----------------------------------------------------------------------
 // Dumping types
 //----------------------------------------------------------------------
 #define DEPTH_INCREMENT 2
 
+#ifndef NDEBUG
+LLVM_DUMP_METHOD void
+ClangASTContext::dump(lldb::opaque_compiler_type_t type) const {
+  if (!type)
+    return;
+  clang::QualType qual_type(GetQualType(type));
+  qual_type.dump();
+}
+#endif
+
 void ClangASTContext::Dump(Stream &s) {
   Decl *tu = Decl::castFromDeclContext(GetTranslationUnitDecl());
   tu->dump(s.AsRawOstream());
 }
 
 void ClangASTContext::DumpValue(
     lldb::opaque_compiler_type_t type, ExecutionContext *exe_ctx, Stream *s,
     lldb::Format format, const DataExtractor &data,

lldb/source/Symbol/CompilerType.cpp

 }
 
 void CompilerType::DumpTypeDescription(Stream *s) const {
   if (IsValid()) {
     m_type_system->DumpTypeDescription(m_type, s);
   }
 }
 
+#ifndef NDEBUG
+LLVM_DUMP_METHOD void CompilerType::dump() const {
+  if (IsValid())
+    m_type_system->dump(m_type);
+  else
+    llvm::errs() << "<invalid>\n";
+}
+#endif
+
 bool CompilerType::GetValueAsScalar(const lldb_private::DataExtractor &data,
                                     lldb::offset_t data_byte_offset,
                                     size_t data_byte_size,
                                     Scalar &value) const {
   if (!IsValid())
     return false;
 
   if (IsAggregateType()) {