[clang] [CIR] Infrastructure: class CIRGenBuilderTy; cache CIR types (PR #119037)

[David Olsen via cfe-commits]

================
@@ -9,22 +9,32 @@ using namespace clang;
 using namespace clang::CIRGen;
 
 CIRGenTypes::CIRGenTypes(CIRGenModule &genModule)
-    : cgm(genModule), context(genModule.getASTContext()) {}
+    : cgm(genModule), context(genModule.getASTContext()),
+      builder(cgm.getBuilder()) {}
 
 CIRGenTypes::~CIRGenTypes() {}
 
+mlir::MLIRContext &CIRGenTypes::getMLIRContext() const {
+  return *builder.getContext();
+}
+
 mlir::Type CIRGenTypes::convertType(QualType type) {
   type = context.getCanonicalType(type);
   const Type *ty = type.getTypePtr();
 
+  // Has the type already been processed?
+  TypeCacheTy::iterator tci = typeCache.find(ty);
+  if (tci != typeCache.end())
+    return tci->second;
+
   // For types that haven't been implemented yet or are otherwise unsupported,
   // report an error and return 'int'.
 
   mlir::Type resultType = nullptr;
   switch (ty->getTypeClass()) {
   case Type::Builtin: {
     switch (cast<BuiltinType>(ty)->getKind()) {
-    // Signed types.
+    // Signed integral types.
----------------
dkolsen-pgi wrote:

I thought about it briefly, but decided that the code complexity was not worth the benefit.  The `typeCache` being added in this commit means each `cir::IntType` will be duplicated only once or twice, not lots of times.  So the benefits of using `cgm.SInt*` are minimal.


https://github.com/llvm/llvm-project/pull/119037