[SILGen] Add metatype to keypath base type for static properties.

Author: amritpan

include/swift/SIL/SILProperty.h

@@ -71,6 +71,8 @@ class SILProperty : public llvm::ilist_node<SILProperty>,
     return Component;
   }
 
+  CanType getBaseType() const;
+
   void print(SILPrintContext &Ctx) const;
   void dump() const;
 

lib/SIL/Verifier/SILVerifier.cpp

@@ -7348,24 +7348,39 @@ void SILFunction::verifySILUndefMap() const {
   }
 }
 
+CanType SILProperty::getBaseType() const {
+  auto *decl = getDecl();
+  auto *dc = decl->getInnermostDeclContext();
+
+  // TODO: base type for global descriptors
+  auto sig = dc->getGenericSignatureOfContext();
+  auto baseTy =
+      dc->getInnermostTypeContext()->getSelfInterfaceType()->getReducedType(
+          sig);
+  if (decl->isStatic())
+    baseTy = CanMetatypeType::get(baseTy);
+
+  if (sig) {
+    auto env = dc->getGenericEnvironmentOfContext();
+    baseTy = env->mapTypeIntoContext(baseTy)->getCanonicalType();
+  }
+
+  return baseTy;
+}
+
 /// Verify that a property descriptor follows invariants.
 void SILProperty::verify(const SILModule &M) const {
   if (!verificationEnabled(M))
     return;
 
   auto *decl = getDecl();
-  auto *dc = decl->getInnermostDeclContext();
-  
-  // TODO: base type for global/static descriptors
-  auto sig = dc->getGenericSignatureOfContext();
-  auto baseTy = dc->getInnermostTypeContext()->getSelfInterfaceType()
-                  ->getReducedType(sig);
+  auto sig = decl->getInnermostDeclContext()->getGenericSignatureOfContext();
   auto leafTy = decl->getValueInterfaceType()->getReducedType(sig);
   SubstitutionMap subs;
   if (sig) {
-    auto env = dc->getGenericEnvironmentOfContext();
+    auto env =
+        decl->getInnermostDeclContext()->getGenericEnvironmentOfContext();
     subs = env->getForwardingSubstitutionMap();
-    baseTy = env->mapTypeIntoContext(baseTy)->getCanonicalType();
     leafTy = env->mapTypeIntoContext(leafTy)->getCanonicalType();
   }
   bool hasIndices = false;
@@ -7386,6 +7401,7 @@ void SILProperty::verify(const SILModule &M) const {
     auto typeExpansionContext =
         TypeExpansionContext::noOpaqueTypeArchetypesSubstitution(
             ResilienceExpansion::Maximal);
+    auto baseTy = getBaseType();
     verifyKeyPathComponent(const_cast<SILModule&>(M),
                            typeExpansionContext,
                            getSerializedKind(),

lib/SILGen/SILGen.cpp

@@ -1978,6 +1978,10 @@ void SILGenModule::tryEmitPropertyDescriptor(AbstractStorageDecl *decl) {
     baseTy = decl->getDeclContext()->getSelfInterfaceType()
                  ->getReducedType(decl->getInnermostDeclContext()
                                       ->getGenericSignatureOfContext());
+    
+    if (decl->isStatic()) {
+      baseTy = MetatypeType::get(baseTy);
+    }
   } else {
     // TODO: Global variables should eventually be referenceable as
     // key paths from (), viz. baseTy = TupleType::getEmpty(getASTContext());