[clang] [lldb] [UBSan][BoundsSafety] Implement support for more expressive "trap reasons" (PR #154618)

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@@ -1813,6 +1813,7 @@ void ScalarExprEmitter::EmitBinOpCheck(
   SanitizerHandler Check;
   SmallVector<llvm::Constant *, 4> StaticData;
   SmallVector<llvm::Value *, 2> DynamicData;
+  std::unique_ptr<RuntimeTrapDiagnosticBuilder> RTDB = nullptr;
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Sirraide wrote:

I don’t think this is the right place to cache and reuse these. If we want caching, then `CodeGenModule::RuntimeDiag()` should handle that internally. I’m also not sure if we need caching at all—just making the inline storage of the `SmallString` in the diagnostic builder a big bigger should suffice for most diagnostics I think.

https://github.com/llvm/llvm-project/pull/154618