[lldb] Add matching based on Python callbacks for data formatters.

This patch adds a new matching method for data formatters, in addition
to the existing exact typename and regex-based matching. The new method
allows users to specify the name of a Python callback function that
takes a `SBType` object and decides whether the type is a match or not.

Here is an overview of the changes performed:

- Add a new `eFormatterMatchCallback` matching type, and logic to handle
  it in `TypeMatcher` and `SBTypeNameSpecifier`.

- Extend `FormattersMatchCandidate` instances with a pointer to the
  current `ScriptInterpreter` and the `TypeImpl` corresponding to the
  candidate type, so we can run registered callbacks and pass the type
  to them. All matcher search functions now receive a
  `FormattersMatchCandidate` instead of a type name.

- Add some glue code to ScriptInterpreterPython and the SWIG bindings to
  allow calling a formatter matching callback. Most of this code is
  modeled after the equivalent code for watchpoint callback functions.

- Add an API test for the new callback-based matching feature.

For more context, please check the RFC thread where this feature was
originally discussed:
https://discourse.llvm.org/t/rfc-python-callback-for-data-formatters-type-matching/64204/11

Differential Revision: https://reviews.llvm.org/D135648

1 files changed, 4 insertions, 3 deletions

diff --git a/lldb/source/DataFormatters/DataVisualization.cpp b/lldb/source/DataFormatters/DataVisualization.cpp
index 53832492aa25..036c9372baf8 100644
--- a/lldb/source/DataFormatters/DataVisualization.cpp
+++ b/lldb/source/DataFormatters/DataVisualization.cpp
@@ -66,10 +66,11 @@ DataVisualization::GetSyntheticForType(lldb::TypeNameSpecifierImplSP type_sp) {
 }
 
 bool DataVisualization::AnyMatches(
-    ConstString type_name, TypeCategoryImpl::FormatCategoryItems items,
-    bool only_enabled, const char **matching_category,
+    const FormattersMatchCandidate &candidate_type,
+    TypeCategoryImpl::FormatCategoryItems items, bool only_enabled,
+    const char **matching_category,
     TypeCategoryImpl::FormatCategoryItems *matching_type) {
-  return GetFormatManager().AnyMatches(type_name, items, only_enabled,
+  return GetFormatManager().AnyMatches(candidate_type, items, only_enabled,
                                        matching_category, matching_type);
 }