Add diagnostics for relation cache size (microsoft#30999)

* Add diagnostics for relation cache size

* Move to extendedDiagnostics

* Single method that returns a 3-property object

* Fix double-space lint

Author: sandersn

src/compiler/checker.ts

@@ -114,6 +114,11 @@ namespace ts {
             getIdentifierCount: () => sum(host.getSourceFiles(), "identifierCount"),
             getSymbolCount: () => sum(host.getSourceFiles(), "symbolCount") + symbolCount,
             getTypeCount: () => typeCount,
+            getRelationCacheSizes: () => ({
+                assignable: assignableRelation.size,
+                identity: identityRelation.size,
+                subtype: subtypeRelation.size,
+            }),
             isUndefinedSymbol: symbol => symbol === undefinedSymbol,
             isArgumentsSymbol: symbol => symbol === argumentsSymbol,
             isUnknownSymbol: symbol => symbol === unknownSymbol,

src/compiler/program.ts

@@ -927,6 +927,7 @@ namespace ts {
             getIdentifierCount: () => getDiagnosticsProducingTypeChecker().getIdentifierCount(),
             getSymbolCount: () => getDiagnosticsProducingTypeChecker().getSymbolCount(),
             getTypeCount: () => getDiagnosticsProducingTypeChecker().getTypeCount(),
+            getRelationCacheSizes: () => getDiagnosticsProducingTypeChecker().getRelationCacheSizes(),
             getFileProcessingDiagnostics: () => fileProcessingDiagnostics,
             getResolvedTypeReferenceDirectives: () => resolvedTypeReferenceDirectives,
             isSourceFileFromExternalLibrary,

src/compiler/types.ts

@@ -2961,6 +2961,7 @@ namespace ts {
         /* @internal */ getIdentifierCount(): number;
         /* @internal */ getSymbolCount(): number;
         /* @internal */ getTypeCount(): number;
+        /* @internal */ getRelationCacheSizes(): { assignable: number, identity: number, subtype: number };
 
         /* @internal */ getFileProcessingDiagnostics(): DiagnosticCollection;
         /* @internal */ getResolvedTypeReferenceDirectives(): Map<ResolvedTypeReferenceDirective | undefined>;
@@ -3246,6 +3247,7 @@ namespace ts {
         /* @internal */ getIdentifierCount(): number;
         /* @internal */ getSymbolCount(): number;
         /* @internal */ getTypeCount(): number;
+        /* @internal */ getRelationCacheSizes(): { assignable: number, identity: number, subtype: number };
 
         /* @internal */ isArrayType(type: Type): boolean;
         /* @internal */ isTupleType(type: Type): boolean;

src/tsc/tsc.ts

@@ -340,6 +340,10 @@ namespace ts {
             const checkTime = performance.getDuration("Check");
             const emitTime = performance.getDuration("Emit");
             if (compilerOptions.extendedDiagnostics) {
+                const caches = program.getRelationCacheSizes();
+                reportCountStatistic("Assignability cache size", caches.assignable);
+                reportCountStatistic("Identity cache size", caches.identity);
+                reportCountStatistic("Subtype cache size", caches.subtype);
                 performance.forEachMeasure((name, duration) => reportTimeStatistic(`${name} time`, duration));
             }
             else {