IRGen: Use an invariant load to load metadata base offset

Author: slavapestov

lib/IRGen/MetadataLayout.cpp

@@ -169,8 +169,10 @@ Offset NominalMetadataLayout::emitOffset(IRGenFunction &IGF,
 
   auto offsetBaseAddr = IGF.Builder.CreateStructGEP(layoutAddr, 0, Size(0));
 
-  // FIXME: Should this be an invariant load?
-  llvm::Value *offsetVal = IGF.Builder.CreateLoad(offsetBaseAddr, "base");
+  auto *loadInst = IGF.Builder.CreateLoad(offsetBaseAddr, "base");
+  IGF.setInvariantLoad(loadInst);
+
+  llvm::Value *offsetVal = loadInst;
 
   auto relativeOffset = offset.getRelativeOffset().getValue();
   if (relativeOffset != 0) {

test/IRGen/class_resilience.swift

@@ -341,7 +341,7 @@ extension ResilientGenericOutsideParent {
 
 // CHECK:      [[ADDR:%.*]] = getelementptr inbounds %T16class_resilience21ResilientGenericChildC, %T16class_resilience21ResilientGenericChildC* %0, i32 0, i32 0, i32 0
 // CHECK-NEXT: [[ISA:%.*]] = load %swift.type*, %swift.type** [[ADDR]]
-// CHECK-NEXT: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ([[BOUNDS]], [[BOUNDS]]* @"$s16class_resilience21ResilientGenericChildCMo", i32 0, i32 0)
+// CHECK-NEXT: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ([[BOUNDS]], [[BOUNDS]]* @"$s16class_resilience21ResilientGenericChildCMo", i32 0, i32 0), align {{4|8}}, !invariant.load
 // CHECK-NEXT: [[METADATA_OFFSET:%.*]] = add [[INT]] [[BASE]], {{4|8}}
 // CHECK-NEXT: [[ISA_ADDR:%.*]] = bitcast %swift.type* [[ISA]] to i8*
 // CHECK-NEXT: [[FIELD_OFFSET_TMP:%.*]] = getelementptr inbounds i8, i8* [[ISA_ADDR]], [[INT]] [[METADATA_OFFSET]]
@@ -371,7 +371,7 @@ extension ResilientGenericOutsideParent {
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc %swift.type* @"$s15resilient_class29ResilientGenericOutsideParentC0B11_resilienceE22genericExtensionMethodxmyF"(%T15resilient_class29ResilientGenericOutsideParentC* swiftself) #0 {
 // CHECK:      [[ISA_ADDR:%.*]] = bitcast %T15resilient_class29ResilientGenericOutsideParentC* %0 to %swift.type**
 // CHECK-NEXT: [[ISA:%.*]] = load %swift.type*, %swift.type** [[ISA_ADDR]]
-// CHECK:      [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ([[BOUNDS]], [[BOUNDS]]* @"$s15resilient_class29ResilientGenericOutsideParentCMo", i32 0, i32 0)
+// CHECK:      [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ([[BOUNDS]], [[BOUNDS]]* @"$s15resilient_class29ResilientGenericOutsideParentCMo", i32 0, i32 0), align {{4|8}}, !invariant.load
 // CHECK-NEXT: [[GENERIC_PARAM_OFFSET:%.*]] = add [[INT]] [[BASE]], 0
 // CHECK-NEXT: [[ISA_TMP:%.*]] = bitcast %swift.type* [[ISA]] to i8*
 // CHECK-NEXT: [[GENERIC_PARAM_TMP:%.*]] = getelementptr inbounds i8, i8* [[ISA_TMP]], [[INT]] [[GENERIC_PARAM_OFFSET]]
@@ -500,7 +500,7 @@ extension ResilientGenericOutsideParent {
 // CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s16class_resilience14ResilientChildC5fields5Int32VvsTj"(i32, %T16class_resilience14ResilientChildC* swiftself)
 // CHECK:      [[ISA_ADDR:%.*]] = getelementptr inbounds %T16class_resilience14ResilientChildC, %T16class_resilience14ResilientChildC* %1, i32 0, i32 0, i32 0
 // CHECK-NEXT: [[ISA:%.*]] = load %swift.type*, %swift.type** [[ISA_ADDR]]
-// CHECK-NEXT: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ([[BOUNDS]], [[BOUNDS]]* @"$s16class_resilience14ResilientChildCMo", i32 0, i32 0)
+// CHECK-NEXT: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ([[BOUNDS]], [[BOUNDS]]* @"$s16class_resilience14ResilientChildCMo", i32 0, i32 0), align {{4|8}}, !invariant.load
 // CHECK-NEXT: [[METADATA_OFFSET:%.*]] = add [[INT]] [[BASE]], {{8|16}}
 // CHECK-NEXT: [[METADATA_BYTES:%.*]] = bitcast %swift.type* [[ISA]] to i8*
 // CHECK-NEXT: [[VTABLE_OFFSET_TMP:%.*]] = getelementptr inbounds i8, i8* [[METADATA_BYTES]], [[INT]] [[METADATA_OFFSET]]

test/IRGen/fixed_layout_class.swift

@@ -35,12 +35,12 @@ public func useGenericRootClassProperty<A>(_ o: GenericOutsideParent<A>) {
   // -- we load the base offset twice, first to get the generic parameter out and
   // then for the property itself.
 
-  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class20GenericOutsideParentCMo", i32 0, i32 0)
+  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class20GenericOutsideParentCMo", i32 0, i32 0), align {{4|8}}, !invariant.load
 
   // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds %T18fixed_layout_class20GenericOutsideParentC, %T18fixed_layout_class20GenericOutsideParentC* %0, i32 0, i32 0, i32 0
   // CHECK: [[METADATA:%.*]] = load %swift.type*, %swift.type** [[METADATA_ADDR]]
 
-  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class20GenericOutsideParentCMo", i32 0, i32 0)
+  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class20GenericOutsideParentCMo", i32 0, i32 0), align {{4|8}}, !invariant.load
   // CHECK: [[FIELD_OFFSET_OFFSET:%.*]] = add [[INT]] [[BASE]], {{4|8}}
 
   // CHECK: [[METADATA_ADDR:%.*]] = bitcast %swift.type* [[METADATA]] to i8*
@@ -65,13 +65,13 @@ public func useGenericSubclassProperty<A>(_ o: GenericOutsideChild<A>) {
   // -- we load the base offset twice, first to get the generic parameter out and
   // then for the property itself.
 
-  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class19GenericOutsideChildCMo", i32 0, i32 0)
+  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class19GenericOutsideChildCMo", i32 0, i32 0), align {{4|8}}, !invariant.load
 
   // CHECK: [[UPCAST:%.*]] = bitcast %T18fixed_layout_class19GenericOutsideChildC* %0 to %T18fixed_layout_class20GenericOutsideParentC*
   // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds %T18fixed_layout_class20GenericOutsideParentC, %T18fixed_layout_class20GenericOutsideParentC* [[UPCAST]], i32 0, i32 0, i32 0
   // CHECK: [[METADATA:%.*]] = load %swift.type*, %swift.type** [[METADATA_ADDR]]
 
-  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class20GenericOutsideParentCMo", i32 0, i32 0)
+  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class20GenericOutsideParentCMo", i32 0, i32 0), align {{4|8}}, !invariant.load
   // CHECK: [[FIELD_OFFSET_OFFSET:%.*]] = add [[INT]] [[BASE]], {{4|8}}
 
   // CHECK: [[METADATA_ADDR:%.*]] = bitcast %swift.type* [[METADATA]] to i8*
@@ -83,7 +83,7 @@ public func useGenericSubclassProperty<A>(_ o: GenericOutsideChild<A>) {
   // CHECK: [[METADATA_ADDR:%.*]] = getelementptr inbounds %T18fixed_layout_class19GenericOutsideChildC, %T18fixed_layout_class19GenericOutsideChildC* %0, i32 0, i32 0, i32 0
   // CHECK: [[METADATA:%.*]] = load %swift.type*, %swift.type** [[METADATA_ADDR]]
 
-  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class19GenericOutsideChildCMo", i32 0, i32 0)
+  // CHECK: [[BASE:%.*]] = load [[INT]], [[INT]]* getelementptr inbounds ({ [[INT]], i32, i32 }, { [[INT]], i32, i32 }* @"$s18fixed_layout_class19GenericOutsideChildCMo", i32 0, i32 0), align {{4|8}}, !invariant.load
   // CHECK: [[FIELD_OFFSET_OFFSET:%.*]] = add [[INT]] [[BASE]], {{4|8}}
 
   // CHECK: [[METADATA_ADDR:%.*]] = bitcast %swift.type* [[METADATA]] to i8*