fix Builtin.sizeof et al for metatypes

Those builtins always need to assume a thick metatype which is a pointer.
In other words the builtins need to use the maximally abstracted type.

rdar://108308786

Author: eeckstein

lib/IRGen/GenBuiltin.cpp

@@ -120,6 +120,12 @@ getLoweredTypeAndTypeInfo(IRGenModule &IGM, Type unloweredType) {
   return {lowered, IGM.getTypeInfo(lowered)};
 }
 
+static std::pair<SILType, const TypeInfo &>
+getMaximallyAbstractedLoweredTypeAndTypeInfo(IRGenModule &IGM, Type unloweredType) {
+  auto lowered = IGM.getLoweredType(AbstractionPattern::getOpaque(), unloweredType);
+  return {lowered, IGM.getTypeInfo(lowered)};
+}
+
 /// emitBuiltinCall - Emit a call to a builtin function.
 void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
                             BuiltinInst *Inst, ArrayRef<SILType> argTypes,

lib/SILOptimizer/IRGenTransforms/TargetConstantFolding.cpp

@@ -141,7 +141,8 @@ class TargetConstantFolding : public SILModuleTransform {
 
   const TypeInfo &getTypeInfoOfBuiltin(BuiltinInst *bi, IRGenModule &IGM) {
     SubstitutionMap subs = bi->getSubstitutions();
-    SILType lowered = IGM.getLoweredType(subs.getReplacementTypes()[0]);
+    SILType lowered = IGM.getLoweredType(AbstractionPattern::getOpaque(),
+                                         subs.getReplacementTypes()[0]);
     return IGM.getTypeInfo(lowered);
   }
 };

test/IRGen/builtins.swift

@@ -1,7 +1,7 @@
 
 // RUN: %target-swift-frontend -module-name builtins -parse-stdlib  -disable-access-control -primary-file %s -emit-ir -o - -disable-objc-attr-requires-foundation-module | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-runtime
 
-// REQUIRES: CPU=x86_64
+// REQUIRES: CPU=x86_64 || CPU=arm64 || CPU=arm64e
 
 import Swift
 
@@ -210,6 +210,16 @@ func sizeof_alignof_test() {
 
 }
 
+// CHECK: define hidden {{.*}}void @"$s8builtins28sizeof_alignof_metatype_testyyF"()
+func sizeof_alignof_metatype_test() {
+  // CHECK: store i64 8, i64*
+  var xs = Builtin.sizeof(Int.Type.self) 
+  // CHECK: store i64 8, i64*
+  var xa = Builtin.alignof(Int.Type.self) 
+  // CHECK: store i64 8, i64*
+  var xt = Builtin.strideof(Int.Type.self) 
+}
+
 // CHECK: define hidden {{.*}}void @"$s8builtins27generic_sizeof_alignof_testyyxlF"
 func generic_sizeof_alignof_test<T>(_: T) {
   // CHECK:      [[T0:%.*]] = getelementptr inbounds %swift.vwtable, %swift.vwtable* [[T:%.*]], i32 0, i32 8

test/SILOptimizer/target-const-prop.swift

@@ -74,6 +74,15 @@ func testit() {
 
   // CHECK-OUTPUT: doubleSize: true
   print("doubleSize: \(S.doubleSize == getSize(S.self) * 2)")
+
+  // CHECK-OUTPUT: metatype-size-1: true
+  print("metatype-size-1: \(MemoryLayout<S.Type>.size == MemoryLayout<UnsafeRawPointer>.size)")
+  // CHECK-OUTPUT: metatype-size-2: true
+  print("metatype-size-2: \(getSize(S.Type.self) == MemoryLayout<UnsafeRawPointer>.size)")
+  // CHECK-OUTPUT: metatype-alignment: true
+  print("metatype-alignment: \(getAlignment(S.Type.self) == MemoryLayout<UnsafeRawPointer>.alignment)")
+  // CHECK-OUTPUT: metatype-stride: true
+  print("metatype-stride: \(getStride(S.Type.self) == MemoryLayout<UnsafeRawPointer>.stride)")
 }
 
 testit()