Index: clang/include/clang/Basic/Attr.td =================================================================== --- clang/include/clang/Basic/Attr.td +++ clang/include/clang/Basic/Attr.td @@ -3473,3 +3473,21 @@ let Subjects = SubjectList<[Function]>; let Documentation = [NoBuiltinDocs]; } + +def AcquireHandle : DeclOrTypeAttr { + let Spellings = [Clang<"acquire_handle">]; + let Subjects = SubjectList<[FunctionLike, ParmVar]>; + let Documentation = [AcquireHandleDocs]; +} + +def UseHandle : DeclOrTypeAttr { + let Spellings = [Clang<"use_handle">]; + let Subjects = SubjectList<[ParmVar]>; + let Documentation = [UseHandleDocs]; +} + +def ReleaseHandle : DeclOrTypeAttr { + let Spellings = [Clang<"release_handle">]; + let Subjects = SubjectList<[ParmVar]>; + let Documentation = [ReleaseHandleDocs]; +} Index: clang/include/clang/Basic/AttrDocs.td =================================================================== --- clang/include/clang/Basic/AttrDocs.td +++ clang/include/clang/Basic/AttrDocs.td @@ -4643,3 +4643,72 @@ } }]; } + +def HandleDocs : DocumentationCategory<"Handle Attributes"> { + let Content = [{ +Handles are a way to identify resources like files, sockets, and processes. +They are more opaque than pointers and widely used in system programming. They +have similar risks such as never releasing a resource associated with a handle, +attempting to use a handle that was already released, or trying to release a +handle twice. Using the annotations below it is possible to make the ownership +of the handles clear: whose responsibility is to release them. They can also +aid static analysis tools to find bugs. + }]; +} + +def AcquireHandleDocs : Documentation { + let Category = HandleDocs; + let Content = [{ +If this annotation is on a function or a function type it is assumed to return +a new handle. In case this annotation is on an output parameter or on the handle +type, the function is assumed to fill the corresponding argument with a new +handle. + +.. code-block:: c++ + + // Output arguments from Zircon. + zx_status_t zx_socket_create(uint32_t options, + zx_handle_t __attribute__((acquire_handle)) * out0, + zx_handle_t* out1 [[clang::acquire_handle]]); + + + // Returned handle. + [[clang::acquire_handle]] int open(const char *path, int oflag, ... ); + int open(const char *path, int oflag, ... ) __attribute__((acquire_handle)); + }]; +} + +def UseHandleDocs : Documentation { + let Category = HandleDocs; + let Content = [{ +A function taking a handle by value might close the handle. If a function +parameter or the parameter's handle type is annotated with `use_handle` it is +assumed to not to change the state of the handle. It is also assumed to require +an open handle to work with. + +.. code-block:: c++ + + zx_status_t zx_port_wait(zx_handle_t handle [[clang::use_handle]], + zx_time_t deadline, + zx_port_packet_t* packet); + // or + zx_status_t zx_port_wait(zx_handle_t __attribute__((use_handle)) handle, + zx_time_t deadline, + zx_port_packet_t* packet); + }]; +} + +def ReleaseHandleDocs : Documentation { + let Category = HandleDocs; + let Content = [{ +If a function parameter or the parameter's handle type is annotated with +`release_handle` it is assumed to close the handle. It is also assumed to +require an open handle to work with. + +.. code-block:: c++ + + zx_status_t zx_handle_close(zx_handle_t handle [[clang::release_handle]]); + // or + zx_status_t zx_handle_close(zx_handle_t __attribute__((release_handle)) handle); + }]; +} Index: clang/include/clang/Basic/DiagnosticSemaKinds.td =================================================================== --- clang/include/clang/Basic/DiagnosticSemaKinds.td +++ clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -3060,7 +3060,7 @@ def err_attribute_wrong_decl_type : Error; def warn_type_attribute_wrong_type : Warning< "'%0' only applies to %select{function|pointer|" - "Objective-C object or block pointer}1 types; type here is %2">, + "Objective-C object or block pointer|non-function}1 types; type here is %2">, InGroup; def warn_incomplete_encoded_type : Warning< "encoding of %0 type is incomplete because %1 component has unknown encoding">, @@ -3121,6 +3121,8 @@ def err_cconv_incomplete_param_type : Error< "parameter %0 must have a complete type to use function %1 with the %2 " "calling convention">; +def err_attribute_output_parameter : Error< + "attribute only applies to output parameters">; def ext_cannot_use_trivial_abi : ExtWarn< "'trivial_abi' cannot be applied to %0">, InGroup; Index: clang/lib/AST/TypePrinter.cpp =================================================================== --- clang/lib/AST/TypePrinter.cpp +++ clang/lib/AST/TypePrinter.cpp @@ -1555,6 +1555,15 @@ case attr::NoDeref: OS << "noderef"; break; + case attr::UseHandle: + OS << "use_handle"; + break; + case attr::AcquireHandle: + OS << "acquire_handle"; + break; + case attr::ReleaseHandle: + OS << "release_handle"; + break; } OS << "))"; } Index: clang/lib/Sema/SemaDeclAttr.cpp =================================================================== --- clang/lib/Sema/SemaDeclAttr.cpp +++ clang/lib/Sema/SemaDeclAttr.cpp @@ -6579,6 +6579,18 @@ handleSimpleAttribute(S, D, AL); } +static void handeAcquireHandleAttr(Sema &S, Decl *D, const ParsedAttr &AL) { + // Warn if the parameter is definitely not an output parameter. + if (const auto *PVD = dyn_cast(D)) { + if (PVD->getType()->isIntegerType()) { + S.Diag(AL.getLoc(), diag::err_attribute_output_parameter) + << AL.getRange(); + return; + } + } + handleSimpleAttribute(S, D, AL); +} + //===----------------------------------------------------------------------===// // Top Level Sema Entry Points //===----------------------------------------------------------------------===// @@ -7353,6 +7365,16 @@ case ParsedAttr::AT_ArmMveAlias: handleArmMveAliasAttr(S, D, AL); break; + + case ParsedAttr::AT_AcquireHandle: + handeAcquireHandleAttr(S, D, AL); + break; + case ParsedAttr::AT_ReleaseHandle: + handleSimpleAttribute(S, D, AL); + break; + case ParsedAttr::AT_UseHandle: + handleSimpleAttribute(S, D, AL); + break; } } Index: clang/lib/Sema/SemaType.cpp =================================================================== --- clang/lib/Sema/SemaType.cpp +++ clang/lib/Sema/SemaType.cpp @@ -7418,6 +7418,21 @@ attrKind == ParsedAttr::AT_OpenCLGenericAddressSpace; } +template +static void handleHandleAttr(TypeProcessingState &State, QualType &CurType, + ParsedAttr &Attr) { + if (CurType->isFunctionType()) { + State.getSema().Diag(Attr.getLoc(), diag::warn_type_attribute_wrong_type) + << Attr.getAttrName()->getName() << 3 << CurType; + Attr.setInvalid(); + return; + } + ASTContext &Ctx = State.getSema().Context; + CurType = State.getAttributedType(createSimpleAttr(Ctx, Attr), + CurType, CurType); + Attr.setUsedAsTypeAttr(); +} + static void processTypeAttrs(TypeProcessingState &state, QualType &type, TypeAttrLocation TAL, ParsedAttributesView &attrs) { @@ -7614,6 +7629,15 @@ else if (!handleFunctionTypeAttr(state, attr, type)) distributeFunctionTypeAttr(state, attr, type); break; + case ParsedAttr::AT_UseHandle: + handleHandleAttr(state, type, attr); + break; + case ParsedAttr::AT_AcquireHandle: + handleHandleAttr(state, type, attr); + break; + case ParsedAttr::AT_ReleaseHandle: + handleHandleAttr(state, type, attr); + break; } // Handle attributes that are defined in a macro. We do not want this to be Index: clang/test/Misc/pragma-attribute-supported-attributes-list.test =================================================================== --- clang/test/Misc/pragma-attribute-supported-attributes-list.test +++ clang/test/Misc/pragma-attribute-supported-attributes-list.test @@ -9,6 +9,7 @@ // CHECK-NEXT: AMDGPUWavesPerEU (SubjectMatchRule_function) // CHECK-NEXT: AVRSignal (SubjectMatchRule_function) // CHECK-NEXT: AbiTag (SubjectMatchRule_record_not_is_union, SubjectMatchRule_variable, SubjectMatchRule_function, SubjectMatchRule_namespace) +// CHECK-NEXT: AcquireHandle (SubjectMatchRule_hasType_functionType, SubjectMatchRule_variable_is_parameter) // CHECK-NEXT: Alias (SubjectMatchRule_function, SubjectMatchRule_variable_is_global) // CHECK-NEXT: AlignValue (SubjectMatchRule_variable, SubjectMatchRule_type_alias) // CHECK-NEXT: AllocSize (SubjectMatchRule_function) @@ -128,6 +129,7 @@ // CHECK-NEXT: ParamTypestate (SubjectMatchRule_variable_is_parameter) // CHECK-NEXT: PassObjectSize (SubjectMatchRule_variable_is_parameter) // CHECK-NEXT: Pointer (SubjectMatchRule_record_not_is_union) +// CHECK-NEXT: ReleaseHandle (SubjectMatchRule_variable_is_parameter) // CHECK-NEXT: RenderScriptKernel (SubjectMatchRule_function) // CHECK-NEXT: ReqdWorkGroupSize (SubjectMatchRule_function) // CHECK-NEXT: Restrict (SubjectMatchRule_function) @@ -145,6 +147,7 @@ // CHECK-NEXT: Target (SubjectMatchRule_function) // CHECK-NEXT: TestTypestate (SubjectMatchRule_function_is_member) // CHECK-NEXT: TrivialABI (SubjectMatchRule_record) +// CHECK-NEXT: UseHandle (SubjectMatchRule_variable_is_parameter) // CHECK-NEXT: VecReturn (SubjectMatchRule_record) // CHECK-NEXT: VecTypeHint (SubjectMatchRule_function) // CHECK-NEXT: WarnUnused (SubjectMatchRule_record) Index: clang/test/Sema/attr-handles.cpp =================================================================== --- /dev/null +++ clang/test/Sema/attr-handles.cpp @@ -0,0 +1,22 @@ +// RUN: %clang_cc1 -fsyntax-only -verify %s + +// Decl annotations. +void f(int *a __attribute__((acquire_handle))); +void (*fp)(int handle [[clang::use_handle]]); +auto lambda = [](int handle [[clang::use_handle]]){}; +void g(int a __attribute__((acquire_handle))); // expected-error {{attribute only applies to output parameters}} +void h(int *a __attribute__((acquire_handle(1)))); // expected-error {{'acquire_handle' attribute takes no arguments}} +__attribute__((release_handle)) int i(); // expected-warning {{'release_handle' attribute only applies to parameters}} +__attribute__((use_handle)) int j(); // expected-warning {{'use_handle' attribute only applies to parameters}} +int a __attribute__((acquire_handle)); // expected-warning {{'acquire_handle' attribute only applies to functions, function pointers, and parameters}} + +// Type annotations. +void ft(int __attribute__((acquire_handle)) * a); +void (*fpt)(int __attribute__((use_handle)) handle); +auto lambdat = [](int __attribute__((use_handle)) handle) -> + int __attribute__((acquire_handle)) { return 0; }; +void gt(int __attribute__((acquire_handle)) a); // expected-error {{attribute only applies to output parameters}} +void ht(int __attribute__((acquire_handle(1))) *a); // expected-error {{'acquire_handle' attribute takes no arguments}} +int it() __attribute__((release_handle)); // expected-warning {{'release_handle' only applies to non-function types; type here is 'int ()'}} +int jt() __attribute__((use_handle)); // expected-warning {{'use_handle' only applies to non-function types; type here is 'int ()'}} +int __attribute__((acquire_handle)) at; // expected-warning {{'acquire_handle' attribute only applies to functions, function pointers, and parameters}} \ No newline at end of file