[IRGen][interop] do not add 'nocapture' to not bitwise takable types

The use of 'nocapture' for parameters and return values is incorrect for C++ types, as they can actually capture a pointer into its own value (e.g. std::string in libstdc++)

rdar://115062687

Author: hyp

lib/IRGen/GenCall.cpp

@@ -266,7 +266,10 @@ static void addIndirectValueParameterAttributes(IRGenModule &IGM,
   llvm::AttrBuilder b(IGM.getLLVMContext());
   // Value parameter pointers can't alias or be captured.
   b.addAttribute(llvm::Attribute::NoAlias);
-  b.addAttribute(llvm::Attribute::NoCapture);
+  // Bitwise takable value types are guaranteed not to capture
+  // a pointer into itself.
+  if (ti.isBitwiseTakable(ResilienceExpansion::Maximal))
+    b.addAttribute(llvm::Attribute::NoCapture);
   // The parameter must reference dereferenceable memory of the type.
   addDereferenceableAttributeToBuilder(IGM, b, ti);
 
@@ -278,9 +281,11 @@ static void addPackParameterAttributes(IRGenModule &IGM,
                                        llvm::AttributeList &attrs,
                                        unsigned argIndex) {
   llvm::AttrBuilder b(IGM.getLLVMContext());
-  // Pack parameter pointers can't alias or be captured.
+  // Pack parameter pointers can't alias.
+  // Note: they are not marked `nocapture` as one
+  // pack parameter could be a value type (e.g. a C++ type)
+  // that captures its own pointer in itself.
   b.addAttribute(llvm::Attribute::NoAlias);
-  b.addAttribute(llvm::Attribute::NoCapture);
   // TODO: we could mark this dereferenceable when the pack has fixed
   // components.
   // TODO: add an alignment attribute
@@ -301,8 +306,10 @@ static void addInoutParameterAttributes(IRGenModule &IGM, SILType paramSILType,
     // attribute if it's a pointer being passed inout.
     b.addAttribute(llvm::Attribute::NoAlias);
   }
-  // Aliasing inouts can't be captured without doing unsafe stuff.
-  b.addAttribute(llvm::Attribute::NoCapture);
+  // Bitwise takable value types are guaranteed not to capture
+  // a pointer into itself.
+  if (ti.isBitwiseTakable(ResilienceExpansion::Maximal))
+    b.addAttribute(llvm::Attribute::NoCapture);
   // The inout must reference dereferenceable memory of the type.
   addDereferenceableAttributeToBuilder(IGM, b, ti);
 
@@ -341,10 +348,14 @@ llvm::CallingConv::ID irgen::expandCallingConv(IRGenModule &IGM,
 static void addIndirectResultAttributes(IRGenModule &IGM,
                                         llvm::AttributeList &attrs,
                                         unsigned paramIndex, bool allowSRet,
-                                        llvm::Type *storageType) {
+                                        llvm::Type *storageType,
+                                        const TypeInfo &typeInfo) {
   llvm::AttrBuilder b(IGM.getLLVMContext());
   b.addAttribute(llvm::Attribute::NoAlias);
-  b.addAttribute(llvm::Attribute::NoCapture);
+  // Bitwise takable value types are guaranteed not to capture
+  // a pointer into itself.
+  if (typeInfo.isBitwiseTakable(ResilienceExpansion::Maximal))
+    b.addAttribute(llvm::Attribute::NoCapture);
   if (allowSRet) {
     assert(storageType);
     b.addStructRetAttr(storageType);
@@ -509,7 +520,7 @@ llvm::Type *SignatureExpansion::addIndirectResult() {
   const TypeInfo &resultTI = IGM.getTypeInfo(resultType);
   auto storageTy = resultTI.getStorageType();
   addIndirectResultAttributes(IGM, Attrs, ParamIRTypes.size(), claimSRet(),
-                              storageTy);
+                              storageTy, resultTI);
   addPointerParameter(storageTy);
   return IGM.VoidTy;
 }
@@ -568,11 +579,12 @@ void SignatureExpansion::expandIndirectResults() {
     auto useSRet = claimSRet();
     // We need to use opaque types or non fixed size storage types because llvm
     // does type based analysis based on the type of sret arguments.
-    if (useSRet && !isa<FixedTypeInfo>(IGM.getTypeInfo(indirectResultType))) {
+    const TypeInfo &typeInfo = IGM.getTypeInfo(indirectResultType);
+    if (useSRet && !isa<FixedTypeInfo>(typeInfo)) {
       storageTy = IGM.OpaqueTy;
     }
     addIndirectResultAttributes(IGM, Attrs, ParamIRTypes.size(), useSRet,
-                                storageTy);
+                                storageTy, typeInfo);
     addPointerParameter(storageTy);
   }
 }
@@ -1459,7 +1471,7 @@ void SignatureExpansion::expandExternalSignatureTypes() {
             param, IGM.getMaximalTypeExpansionContext());
         auto &paramTI = cast<FixedTypeInfo>(IGM.getTypeInfo(paramTy));
         addIndirectResultAttributes(IGM, Attrs, getCurParamIndex(), claimSRet(),
-                                    paramTI.getStorageType());
+                                    paramTI.getStorageType(), paramTI);
         break;
       }
       }

test/AutoDiff/IRGen/runtime.swift

@@ -12,7 +12,7 @@ func test_context_builtins_with_type<T>(t: T) {
   UnsafeMutableRawPointer(newBuffer).storeBytes(of: t, as: T.self)
 }
 
-// CHECK-LABEL: define{{.*}}@test_context_builtins_with_type(ptr noalias nocapture %0, ptr %T)
+// CHECK-LABEL: define{{.*}}@test_context_builtins_with_type(ptr noalias %0, ptr %T)
 // CHECK: entry:
 // CHECK:   [[CTX:%.*]] = call swiftcc ptr @swift_autoDiffCreateLinearMapContextWithType(ptr %T)
 // CHECK:   call swiftcc ptr @swift_autoDiffProjectTopLevelSubcontext(ptr [[CTX]])

test/DebugInfo/inlined-generics-basic.swift

@@ -44,7 +44,7 @@ public class C<R> {
 
   // SIL-LABEL: // C.f<A>(_:)
   // IR-LABEL: define {{.*}} @"$s1A1CC1fyyqd__lF"
-  // IR-SAME: nocapture %[[ARG_0:.*]], {{.*}} %[[ARG_S:.*]],
+  // IR-SAME: %[[ARG_0:.*]], {{.*}} %[[ARG_S:.*]],
 #sourceLocation(file: "f.swift", line: 1)
   public func f<S>(_ s: S) {
     // SIL: debug_value %0 : $*S, let, name "s", argno 1, expr op_deref, {{.*}} scope [[F]]

test/DebugInfo/move_function_dbginfo.swift

@@ -218,7 +218,7 @@ public func copyableVarArgTest(_ k: inout Klass) {
     k.doSomething()
 }
 
-// CHECK-LABEL: define swiftcc void @"$s21move_function_dbginfo20addressOnlyValueTestyyxAA1PRzlF"(ptr noalias nocapture %0, ptr %T, ptr %T.P)
+// CHECK-LABEL: define swiftcc void @"$s21move_function_dbginfo20addressOnlyValueTestyyxAA1PRzlF"(ptr noalias %0, ptr %T, ptr %T.P)
 // CHECK: @llvm.dbg.addr(metadata ptr %{{.*}}, metadata ![[K_ADDR_LET_METADATA:[0-9]+]], metadata !DIExpression()), !dbg ![[ADDR_LOC:[0-9]*]]
 // CHECK-NEXT: br
 // CHECK: @llvm.dbg.value(metadata ptr undef, metadata ![[K_ADDR_LET_METADATA]], metadata !DIExpression()), !dbg ![[ADDR_LOC]]
@@ -308,7 +308,7 @@ public func addressOnlyValueArgTest<T : P>(_ k: __owned T) {
     m.doSomething()
 }
 
-// CHECK-LABEL: define swiftcc void @"$s21move_function_dbginfo18addressOnlyVarTestyyxAA1PRzlF"(ptr noalias nocapture %0, ptr %T, ptr %T.P)
+// CHECK-LABEL: define swiftcc void @"$s21move_function_dbginfo18addressOnlyVarTestyyxAA1PRzlF"(ptr noalias %0, ptr %T, ptr %T.P)
 // CHECK: @llvm.dbg.addr(metadata ptr %{{.*}}, metadata ![[K_ADDRONLY_VAR_METADATA:[0-9]+]], metadata !DIExpression()), !dbg ![[ADDR_LOC:[0-9]*]]
 // CHECK-NEXT: br
 // CHECK: @llvm.dbg.value(metadata ptr undef, metadata ![[K_ADDRONLY_VAR_METADATA]], metadata !DIExpression()), !dbg ![[ADDR_LOC]]

test/DebugInfo/struct_resilience.swift

@@ -11,8 +11,8 @@
 //
 import resilient_struct
 
-// CHECK-LABEL: define{{.*}} swiftcc void @"$s17struct_resilience9takesSizeyy010resilient_A00D0VF"(ptr noalias nocapture %0)
-// CHECK-LLDB-LABEL: define{{.*}} swiftcc void @"$s17struct_resilience9takesSizeyy010resilient_A00D0VF"(ptr noalias nocapture dereferenceable({{8|16}}) %0)
+// CHECK-LABEL: define{{.*}} swiftcc void @"$s17struct_resilience9takesSizeyy010resilient_A00D0VF"(ptr noalias %0)
+// CHECK-LLDB-LABEL: define{{.*}} swiftcc void @"$s17struct_resilience9takesSizeyy010resilient_A00D0VF"(ptr noalias dereferenceable({{8|16}}) %0)
 public func takesSize(_ s: Size) {}
 
 

test/Distributed/distributed_actor_accessor_thunks_64bit.swift

@@ -94,7 +94,7 @@ public distributed actor MyOtherActor {
 
 // CHECK: define hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTE"
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTETF"(ptr swiftasync %0, ptr nocapture %1, ptr %2, ptr %3, {{.*}}, ptr [[ACTOR:%.*]], ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple1yySiYaKFTETF"(ptr swiftasync %0, ptr %1, ptr %2, ptr %3, {{.*}}, ptr [[ACTOR:%.*]], ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 /// Read the current offset and cast an element to `Int`
 
@@ -116,7 +116,7 @@ public distributed actor MyOtherActor {
 // CHECK: missing-witness1:
 // CHECK-NEXT: call void @llvm.trap()
 // CHECK-NEXT: unreachable
-// CHECK: call swiftcc void @"$s27FakeDistributedActorSystems0A17InvocationDecoderC18decodeNextArgumentxyKSeRzSERzlF"(ptr noalias nocapture sret(%swift.opaque) [[ARG_0_VALUE_BUF]], ptr %arg_type, ptr [[ENCODABLE_WITNESS]], ptr [[DECODABLE_WITNESS]], ptr swiftself [[DECODER]], ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
+// CHECK: call swiftcc void @"$s27FakeDistributedActorSystems0A17InvocationDecoderC18decodeNextArgumentxyKSeRzSERzlF"(ptr noalias sret(%swift.opaque) [[ARG_0_VALUE_BUF]], ptr %arg_type, ptr [[ENCODABLE_WITNESS]], ptr [[DECODABLE_WITNESS]], ptr swiftself [[DECODER]], ptr noalias nocapture swifterror dereferenceable(8) %swifterror)
 
 // CHECK: store ptr null, ptr %swifterror
 // CHECK-NEXT: %._value = getelementptr inbounds %TSi, ptr [[ARG_0_VALUE_BUF]], i32 0, i32 0
@@ -192,7 +192,7 @@ public distributed actor MyOtherActor {
 // CHECK: define hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTE"
 
 /// !!! in `simple3` interesting bits are: argument value extraction (because string is exploded into N arguments) and call to distributed thunk
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTETF"(ptr swiftasync %0, ptr nocapture [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUFF:%.*]], ptr [[SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr [[ACTOR]], ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7simple3ySiSSYaKFTETF"(ptr swiftasync %0, ptr [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUFF:%.*]], ptr [[SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr [[ACTOR]], ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 
 // CHECK: [[ARG_SIZE:%.*]] = and i64 {{.*}}, -16
@@ -232,7 +232,7 @@ public distributed actor MyOtherActor {
 
 // CHECK: define hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC16single_case_enumyAA7SimpleEOAFYaKFTE"
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC16single_case_enumyAA7SimpleEOAFYaKFTETF"(ptr swiftasync %0, ptr nocapture [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUFF:%.*]], ptr [[SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr [[ACTOR]], ptr [[DECODER_TYPE]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC16single_case_enumyAA7SimpleEOAFYaKFTETF"(ptr swiftasync %0, ptr [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUFF:%.*]], ptr [[SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr [[ACTOR]], ptr [[DECODER_TYPE]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 /// Let's check that the call doesn't have any arguments and returns nothing.
 
@@ -272,7 +272,7 @@ public distributed actor MyOtherActor {
 
 // CHECK: define hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7complexyAA11LargeStructVSaySiG_AA3ObjCSSSgAFtYaKFTE"
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7complexyAA11LargeStructVSaySiG_AA3ObjCSSSgAFtYaKFTETF"(ptr swiftasync {{.*}}, ptr nocapture [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUFF:%.*]], ptr [[SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr [[ACTOR]], ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC7complexyAA11LargeStructVSaySiG_AA3ObjCSSSgAFtYaKFTETF"(ptr swiftasync {{.*}}, ptr [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUFF:%.*]], ptr [[SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr [[ACTOR]], ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 /// First, let's check that all of the different argument types here are loaded correctly.
 
@@ -319,7 +319,7 @@ public distributed actor MyOtherActor {
 
 /// ---> Accessor for `genericArgs`
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC11genericArgsyyx_Sayq_GtYaKSeRzSERzSeR_SER_r0_lFTETF"(ptr swiftasync %0, ptr  nocapture [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUF:%.*]], ptr [[GENERIC_SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr [[ACTOR:%.*]], ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors7MyActorC11genericArgsyyx_Sayq_GtYaKSeRzSERzSeR_SER_r0_lFTETF"(ptr swiftasync %0, ptr  [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUF:%.*]], ptr [[GENERIC_SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr [[ACTOR:%.*]], ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
 
 /// ---> Load `T`
 
@@ -368,7 +368,7 @@ public distributed actor MyOtherActor {
 
 /// Let's check that there is argument decoding since parameter list is empty
 
-// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors12MyOtherActorC5emptyyyYaKFTETF"(ptr swiftasync {{.*}}, ptr nocapture [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUFF:%.*]], ptr [[SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr {{.*}}, ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
+// CHECK: define linkonce_odr hidden swift{{(tail)?}}cc void @"$s27distributed_actor_accessors12MyOtherActorC5emptyyyYaKFTETF"(ptr swiftasync {{.*}}, ptr [[ARG_DECODER:%.*]], ptr [[ARG_TYPES:%.*]], ptr [[RESULT_BUFF:%.*]], ptr [[SUBS:%.*]], ptr [[WITNESS_TABLES:%.*]], i64 [[NUM_WITNESS_TABLES:%.*]], ptr {{.*}}, ptr [[DECODER_TYPE:%.*]], ptr [[DECODER_PROTOCOL_WITNESS:%.*]])
 // CHECK-NEXT: entry:
 // CHECK-NEXT: {{.*}} = alloca ptr
 // CHECK-NEXT: %swifterror = alloca swifterror ptr

test/IRGen/TestABIInaccessible.swift

@@ -8,7 +8,7 @@ public struct AnotherType<T> {
 }
 
 // Don't pass the metadata of Private<T> to AnotherType<T>'s outlined destroy.
-// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s4main4copyyAA11AnotherTypeVyxGAElF"(ptr noalias nocapture sret({{.*}}) %0, ptr noalias nocapture %1, ptr %T)
+// CHECK-LABEL: define{{( dllexport)?}}{{( protected)?}} swiftcc void @"$s4main4copyyAA11AnotherTypeVyxGAElF"(ptr noalias sret({{.*}}) %0, ptr noalias %1, ptr %T)
 // CHECK:  [[MD:%.*]] = call swiftcc %swift.metadata_response @"$s4main11AnotherTypeVMa"(i{{.*}} 0, ptr %T)
 // CHECK:  [[MD1:%.*]] = extractvalue %swift.metadata_response [[MD]], 0
 // CHECK:  [[MD2:%.*]] = call swiftcc %swift.metadata_response @"$s4main6PublicVMa"(i{{.*}} 0, ptr %T)

test/IRGen/archetype_resilience.sil

@@ -16,7 +16,7 @@ public enum EnumWithClassArchetypeAndDynamicSize<T : AnyObject> {
   case B(Size)
 }
 
-// CHECK-LABEL: define swiftcc void @copyDynamicMultiEnum(ptr %"EnumWithClassArchetypeAndDynamicSize<T>", ptr %U, ptr noalias nocapture swiftself %0)
+// CHECK-LABEL: define swiftcc void @copyDynamicMultiEnum(ptr %"EnumWithClassArchetypeAndDynamicSize<T>", ptr %U, ptr noalias swiftself %0)
 // CHECK: call ptr @"$s20archetype_resilience36EnumWithClassArchetypeAndDynamicSizeOyxGRlzCr0_lWOc"(ptr %0, ptr {{.*}}, ptr %"EnumWithClassArchetypeAndDynamicSize<T>")
 // CHECK: ret void
 sil [ossa] @copyDynamicMultiEnum : $@convention(method) <T, U where T: AnyObject> (@in_guaranteed EnumWithClassArchetypeAndDynamicSize<T>) -> () {