[MsDemangle] Use LLVM style RTTI for AST nodes

[Nerixyz]

The inheritance hierarchy for llvm::ms_demangle::Node (doxygen) is a bit more involved. One thing that's missing without RTTI is the ability to determine if a node is a symbol, identifier, or type (or one would need to check for every kind).

This PR adds support for dyn_cast, isa, and friends to llvm::ms_demangle::Node. As the type already has a kind(), this mainly adds classof to the nodes as well as some start and end markers in the NodeKind enum.

[zmodem]

One thing that's missing without RTTI is the ability to determine if a node is a symbol, identifier, or type (or one would need to check for every kind).

Do you have an example in mind, where this added RTTI functionality would make the code simpler?

[Nerixyz]

Do you have an example in mind, where this added RTTI functionality would make the code simpler?

Yes, I wanted to add rich function demangling info for MS to LLDB (#143149). For this, I need to keep track where certain parts of the demangled name are. Specifically, the basename and function arguments. Here is my WIP, which still has some unrelated changes. RTTI is used there for checking if a node is an identifier and to be able to access its template parameters.

LLDB already does this for the Itanium demangling in DemangledNameInfo. It would be even better if that visitor/output buffer could be reused somehow, as MS-demangle also uses that class. However, it doesn't call printLeft/printRight, because the node types are different.

[zmodem]

Okay, adding this sounds good to me.

[zmodem]

I don't think we should introduce new enumerator values for the Start/End values. The guideline is that there should be one enumerator per concrete class.

How about something like:

enum class NodeKind {
  Unknown,

  SymbolStart,
  EncodedStringLiteral = SymbolStart,
  ...
  VariableSymbol,
  SymbolEnd = VariableSymbol,
  ...

[zmodem]

lgtm

[Nerixyz]

@zmodem I can't merge this on my own. Could you please merge this for me?

[llvm-ci]

LLVM Buildbot has detected a new failure on builder flang-arm64-windows-msvc running on linaro-armv8-windows-msvc-01 while building llvm at step 7 "test-build-unified-tree-check-flang".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/207/builds/3367

Here is the relevant piece of the build log for the reference

Step 7 (test-build-unified-tree-check-flang) failure: test (failure)
******************** TEST 'Flang :: Lower/OpenMP/wsloop-reduction-logical-kinds.f90' FAILED ********************
Exit Code: 2

Command Output (stdout):
--
# RUN: at line 1
c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe -fc1 -emit-hlfir -fopenmp -o - C:\Users\tcwg\llvm-worker\flang-arm64-windows-msvc\llvm-project\flang\test\Lower\OpenMP\wsloop-reduction-logical-kinds.f90 | c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\filecheck.exe C:\Users\tcwg\llvm-worker\flang-arm64-windows-msvc\llvm-project\flang\test\Lower\OpenMP\wsloop-reduction-logical-kinds.f90
# executed command: 'c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe' -fc1 -emit-hlfir -fopenmp -o - 'C:\Users\tcwg\llvm-worker\flang-arm64-windows-msvc\llvm-project\flang\test\Lower\OpenMP\wsloop-reduction-logical-kinds.f90'
# .---command stderr------------
# | PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
# | Stack dump:
# | 0.	Program arguments: c:\\users\\tcwg\\llvm-worker\\flang-arm64-windows-msvc\\build\\bin\\flang.exe -fc1 -emit-hlfir -fopenmp -o - C:\\Users\\tcwg\\llvm-worker\\flang-arm64-windows-msvc\\llvm-project\\flang\\test\\Lower\\OpenMP\\wsloop-reduction-logical-kinds.f90
# | Exception Code: 0xC0000005
# |  #0 0x00007ff617921c24 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x1a91c24)
# |  #1 0x00007ff61791f90c (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x1a8f90c)
# |  #2 0x00007ff61791d7a0 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x1a8d7a0)
# |  #3 0x00007ff6179234b4 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x1a934b4)
# |  #4 0x00007ff61791d308 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x1a8d308)
# |  #5 0x00007ff61673ca48 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x8aca48)
# |  #6 0x00007ff616785ea8 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x8f5ea8)
# |  #7 0x00007ff61682f2ec (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x99f2ec)
# |  #8 0x00007ff6167852e4 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x8f52e4)
# |  #9 0x00007ff615f28ac0 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x98ac0)
# | #10 0x00007ff615f3ea88 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0xaea88)
# | #11 0x00007ff615e934e8 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x34e8)
# | #12 0x00007ff615e920a4 (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x20a4)
# | #13 0x00007ff61ab4e6f8 mlir::detail::FallbackTypeIDResolver::registerImplicitTypeID(class llvm::StringRef) (c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\flang.exe+0x4cbe6f8)
# | #14 0x29077ff61ab4e794
# `-----------------------------
# error: command failed with exit status: 0xc0000005
# executed command: 'c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\filecheck.exe' 'C:\Users\tcwg\llvm-worker\flang-arm64-windows-msvc\llvm-project\flang\test\Lower\OpenMP\wsloop-reduction-logical-kinds.f90'
# .---command stderr------------
# | FileCheck error: '<stdin>' is empty.
# | FileCheck command line:  c:\users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\bin\filecheck.exe C:\Users\tcwg\llvm-worker\flang-arm64-windows-msvc\llvm-project\flang\test\Lower\OpenMP\wsloop-reduction-logical-kinds.f90
# `-----------------------------
# error: command failed with exit status: 2

--

********************

[zmodem]

LLVM Buildbot has detected a new failure on builder flang-arm64-windows-msvc

The next build (https://lab.llvm.org/buildbot/#/builders/207/builds/3368) is green, so that was a flake.