[clang] [C++20][Modules] Use `MultiOnDiskHashTable` to improve the performance of header search algorithm. (PR #155350)

[Chuanqi Xu via cfe-commits]

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@@ -373,6 +373,9 @@ class HeaderFileInfoTrait {
   ModuleFile &M;
 
 public:
+  // Maximum number of lookup tables we allow before condensing the tables.
+  static const int MaxTables = 64;
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ChuanqiXu9 wrote:

Out of curiosity, is this tuned? Or is it set randomly?

https://github.com/llvm/llvm-project/pull/155350