[clang] [llvm] [DirectX] Validate registers are bound to root signature (PR #146785)

[Chris B via llvm-commits]

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@@ -136,6 +136,51 @@ struct OverlappingRanges {
 llvm::SmallVector<OverlappingRanges>
 findOverlappingRanges(llvm::SmallVector<RangeInfo> &Infos);
 
+class RootSignatureBindingValidation {
+private:
+  llvm::SmallVector<RangeInfo, 16> Bindings;
+  struct TypeRange {
+    uint32_t Start;
+    uint32_t End;
+  };
+  std::unordered_map<dxil::ResourceClass, TypeRange> Ranges;
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llvm-beanz wrote:

The LLVM Programmers manual explicitly states:
> We never use containers like unordered_map because they are generally very expensive (each insertion requires a malloc).

(Source: https://llvm.org/docs/ProgrammersManual.html#other-map-like-container-options)

`llvm::DenseMap` is generally preferred. That said, since `dxil::ResourceClass` has a valid value range [0,3], maybe we should just declare a 4-element array...

https://github.com/llvm/llvm-project/pull/146785