[clang] [clang-repl] Lay the basic infrastructure for pretty printing of types (PR #148701)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> > Apologies, trying to reproduce it locally now.
> 
> @qinkunbao, I am stuck reproducing this locally. My platform is ubuntu 22, x86x64:
> 
> The build seems stuck quite early on.
> 
> What am I doing wrong?

That's a failure with the tablegen parser (`TGParser`) which you didn't change in this PR. So I'm not certain that's related to your changes?

> The msan bot complains about line 202 from:
> 
> https://github.com/llvm/llvm-project/blob/33455825428f9e1b7998a66e228da7f6d483acf8/clang/lib/Interpreter/InterpreterValuePrinter.cpp#L200-L204
> 
> I did run the failing test with valgrind and it seemed happy. Could that be a false positive?

That's a failure with your new code and seems more likely to be related to this PR. The issue appears to be that we're getting a `ConstantArrayType` that's corrupted somehow; I think the issue may be with `V` because `getType()` doesn't do any sort of validation:
```
QualType Value::getType() const {
  return QualType::getFromOpaquePtr(OpaqueType);
}
```
So maybe there's a lifetime issue somewhere?

https://github.com/llvm/llvm-project/pull/148701