@vgvassilev @anutosh491 This is what it took for me to enable running
ClangReplInterpreterTests in an Emscripten environment. When I ran this
patch for llvm 20 we could run InterpreterTest.InstantiateTemplate , but
now it crashes gtest when running in node. Let me know what you think.

This patch improves the design of the IncrementalParser and Interpreter
classes. Now the incremental parser is only responsible for building the
partial translation unit declaration and the AST, while the Interpreter
fills in the lower level llvm::Module and other JIT-related
infrastructure. Finally the Interpreter class now orchestrates the AST
and the LLVM IR with the IncrementalParser and IncrementalExecutor
classes.

The design improvement allows us to rework some of the logic that
extracts an interpreter value into the clang::Value object. The new
implementation simplifies use-cases which are used for out-of-process
execution by allowing interpreter to be inherited or customized with an
clang::ASTConsumer.

This change will enable completing the pretty printing work which is in
llvm/llvm-project#84769

And sort out some unused headers

Reduce code bloat by checking test requirements in a common test fixture

See more details: https://lab.llvm.org/buildbot/#/builders/119/builds/16346

Behalf of @vgvassilev

This patch contains changes from
002d471a4a3cd8b429e4ca7c84fd54a642e50e4c, in
addition to a bug fix that added a virtual destructor to
`CompletionContextHandler`

The original changes in the orginal commit piggybacks on clang's
semantic modules to enable semantic completion.  In particular, we use
`CodeCompletionContext` to differentiate two types of code completion.
We also
extract the relevant type information from it.

Reverts llvm/llvm-project#67349

There are some issues with the sanitizers. We will reland once that's fixed.

Differential Revision: https://reviews.llvm.org/D159128

These newly added tests fail on AIX with error `LLVM ERROR: Incompatible object format!`. Disable them for now while we investigate.

Reviewed By: capfredf, shchenz

Differential Revision: https://reviews.llvm.org/D159213