IRGen: Don't emit lazy accessor for witness table of conformance involving DynamicSelfType

Fixes <https://bugs.swift.org/browse/SR-9295>.

Author: slavapestov

lib/IRGen/GenProto.cpp

@@ -1100,7 +1100,8 @@ class AccessorConformanceInfo : public ConformanceInfo {
   llvm::Value *getTable(IRGenFunction &IGF,
                         llvm::Value **typeMetadataCache) const override {
     // If we're looking up a dependent type, we can't cache the result.
-    if (Conformance->getType()->hasArchetype()) {
+    if (Conformance->getType()->hasArchetype() ||
+        Conformance->getType()->hasDynamicSelfType()) {
       return emitWitnessTableAccessorCall(IGF, Conformance,
                                           typeMetadataCache);
     }

test/IRGen/dynamic_self_metadata.swift

@@ -12,6 +12,18 @@
 }
 // CHECK-LABEL: define hidden swiftcc void @"$s21dynamic_self_metadata2idyxxlF"
 
+protocol P {
+  associatedtype T
+}
+
+extension P {
+  func f() {}
+}
+
+struct G<T> : P {
+  var t: T
+}
+
 class C {
   class func fromMetatype() -> Self? { return nil }
   // CHECK-LABEL: define hidden swiftcc i64 @"$s21dynamic_self_metadata1CC12fromMetatypeACXDSgyFZ"(%swift.type* swiftself)
@@ -30,4 +42,17 @@ class C {
   // CHECK: [[T0:%.+]] = call swiftcc %swift.metadata_response @"$sSqMa"(i64 0, %swift.type* [[TYPE1]])
   // CHECK: [[TYPE2:%.+]] = extractvalue %swift.metadata_response [[T0]], 0
   // CHECK: call swiftcc void @"$s21dynamic_self_metadata2idyxxlF"({{.*}}, %swift.type* [[TYPE2]])
+
+  func dynamicSelfConformingType() -> Self? {
+    _ = G(t: self).f()
+    return nil
+  }
+  // CHECK-LABEL: define hidden swiftcc i64 @"$s21dynamic_self_metadata1CC0A18SelfConformingTypeACXDSgyF"(%T21dynamic_self_metadata1CC* swiftself)
+  // CHECK: [[SELF:%.*]] = bitcast %T21dynamic_self_metadata1CC* %0 to %objc_object*
+  // CHECK: [[SELF_TYPE:%.*]] = call %swift.type* @swift_getObjectType(%objc_object* [[SELF]])
+  // CHECK: [[SELF:%.*]] = bitcast %T21dynamic_self_metadata1CC* %0 to %objc_object*
+  // CHECK: [[SELF_TYPE:%.*]] = call %swift.type* @swift_getObjectType(%objc_object* [[SELF]])
+  // CHECK: [[METADATA_RESPONSE:%.*]] = call swiftcc %swift.metadata_response @"$s21dynamic_self_metadata1GVMa"(i64 0, %swift.type* [[SELF_TYPE]])
+  // CHECK: [[METADATA:%.*]] =  extractvalue %swift.metadata_response [[METADATA_RESPONSE]], 0
+  // CHECK: call i8** @swift_getWitnessTable(%swift.protocol_conformance_descriptor* bitcast ({{.*}} @"$s21dynamic_self_metadata1GVyxGAA1PAAMc" to %swift.protocol_conformance_descriptor*), %swift.type* [[METADATA]], i8*** undef)
 }