[OBJC] Add attribute to mark Objective C class as non-lazy
A non-lazy class will be initialized eagerly when the Objective-C runtime is
loaded. This is required for certain system classes which have instances allocated in
non-standard ways, such as the classes for blocks and constant strings.
Adding this attribute is essentially equivalent to providing a trivial
+load method but avoids the (fairly small) load-time overheads associated
with defining and calling such a method.
Differential Revision: https://reviews.llvm.org/D56555
llvm-svn: 353116
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 3b7b0b0..8b99efc 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -1758,6 +1758,13 @@
let Documentation = [Undocumented];
}
+def ObjCNonLazyClass : Attr {
+ let Spellings = [Clang<"objc_nonlazy_class">];
+ let Subjects = SubjectList<[ObjCInterface], ErrorDiag>;
+ let LangOpts = [ObjC];
+ let Documentation = [ObjCNonLazyClassDocs];
+}
+
def ObjCSubclassingRestricted : InheritableAttr {
let Spellings = [Clang<"objc_subclassing_restricted">];
let Subjects = SubjectList<[ObjCInterface], ErrorDiag>;
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index d316993..7f927a9 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3699,6 +3699,19 @@
}];
}
+def ObjCNonLazyClassDocs : Documentation {
+ let Category = DocCatType;
+ let Content = [{
+This attribute can be added to an Objective-C ``@interface`` declaration to
+add the class to the list of non-lazily initialized classes. A non-lazy class
+will be initialized eagerly when the Objective-C runtime is loaded. This is
+required for certain system classes which have instances allocated in
+non-standard ways, such as the classes for blocks and constant strings. Adding
+this attribute is essentially equivalent to providing a trivial `+load` method
+but avoids the (fairly small) load-time overheads associated with defining and
+calling such a method.
+ }];
+}
def SelectAnyDocs : Documentation {
let Category = DocCatType;
diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 20b5a86..7822a95 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -6261,9 +6261,10 @@
return GV;
}
-bool
-CGObjCNonFragileABIMac::ImplementationIsNonLazy(const ObjCImplDecl *OD) const {
- return OD->getClassMethod(GetNullarySelector("load")) != nullptr;
+bool CGObjCNonFragileABIMac::ImplementationIsNonLazy(
+ const ObjCImplDecl *OD) const {
+ return OD->getClassMethod(GetNullarySelector("load")) != nullptr ||
+ OD->getClassInterface()->hasAttr<ObjCNonLazyClassAttr>();
}
void CGObjCNonFragileABIMac::GetClassSizeInfo(const ObjCImplementationDecl *OID,
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 7eafdcc..bb69070 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -6832,6 +6832,9 @@
case ParsedAttr::AT_ObjCRootClass:
handleSimpleAttribute<ObjCRootClassAttr>(S, D, AL);
break;
+ case ParsedAttr::AT_ObjCNonLazyClass:
+ handleSimpleAttribute<ObjCNonLazyClassAttr>(S, D, AL);
+ break;
case ParsedAttr::AT_ObjCSubclassingRestricted:
handleSimpleAttribute<ObjCSubclassingRestrictedAttr>(S, D, AL);
break;
diff --git a/clang/test/CodeGenObjC/non-lazy-classes.m b/clang/test/CodeGenObjC/non-lazy-classes.m
index b04b020..aeb2a0d 100644
--- a/clang/test/CodeGenObjC/non-lazy-classes.m
+++ b/clang/test/CodeGenObjC/non-lazy-classes.m
@@ -1,6 +1,6 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -Wno-objc-root-class -emit-llvm -o - %s | \
// RUN: FileCheck %s
-// CHECK: @"OBJC_LABEL_NONLAZY_CLASS_$" = private global [1 x {{.*}}] {{.*}}@"OBJC_CLASS_$_A"{{.*}}, section "__DATA,__objc_nlclslist,regular,no_dead_strip", align 8
+// CHECK: @"OBJC_LABEL_NONLAZY_CLASS_$" = private global [2 x {{.*}}]{{.*}}@"OBJC_CLASS_$_A"{{.*}},{{.*}}@"OBJC_CLASS_$_D"{{.*}} section "__DATA,__objc_nlclslist,regular,no_dead_strip", align 8
// CHECK: @"OBJC_LABEL_NONLAZY_CATEGORY_$" = private global [1 x {{.*}}] {{.*}}@"\01l_OBJC_$_CATEGORY_A_$_Cat"{{.*}}, section "__DATA,__objc_nlcatlist,regular,no_dead_strip", align 8
@interface A @end
@@ -30,3 +30,8 @@
@interface C : A @end
@implementation C
@end
+
+__attribute__((objc_nonlazy_class))
+@interface D @end
+
+@implementation D @end
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index 0fe7ef4..2dc03a4 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -100,6 +100,7 @@
// CHECK-NEXT: ObjCExplicitProtocolImpl (SubjectMatchRule_objc_protocol)
// CHECK-NEXT: ObjCExternallyRetained (SubjectMatchRule_variable_not_is_parameter, SubjectMatchRule_function, SubjectMatchRule_block, SubjectMatchRule_objc_method)
// CHECK-NEXT: ObjCMethodFamily (SubjectMatchRule_objc_method)
+// CHECK-NEXT: ObjCNonLazyClass (SubjectMatchRule_objc_interface)
// CHECK-NEXT: ObjCPreciseLifetime (SubjectMatchRule_variable)
// CHECK-NEXT: ObjCRequiresPropertyDefs (SubjectMatchRule_objc_interface)
// CHECK-NEXT: ObjCRequiresSuper (SubjectMatchRule_objc_method)
diff --git a/clang/test/SemaObjC/attr-objc-non-lazy.m b/clang/test/SemaObjC/attr-objc-non-lazy.m
new file mode 100644
index 0000000..5dc88f7
--- /dev/null
+++ b/clang/test/SemaObjC/attr-objc-non-lazy.m
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -verify -Wno-objc-root-class -fsyntax-only %s
+
+__attribute__((objc_nonlazy_class))
+@interface A
+@end
+@implementation A
+@end
+
+__attribute__((objc_nonlazy_class)) int X; // expected-error {{'objc_nonlazy_class' attribute only applies to Objective-C interfaces}}
+
+__attribute__((objc_nonlazy_class()))
+@interface B
+@end
+@implementation B
+@end
+
+__attribute__((objc_nonlazy_class("foo"))) // expected-error{{'objc_nonlazy_class' attribute takes no arguments}}
+@interface C
+@end
+@implementation C
+@end
+
+__attribute__((objc_nonlazy_class)) // expected-error {{'objc_nonlazy_class' attribute only applies to Objective-C interfaces}}
+@protocol B
+@end
+
+__attribute__((objc_nonlazy_class)) // expected-error {{'objc_nonlazy_class' attribute only applies to Objective-C interfaces}}
+void foo();
+
+@interface E
+@end
+__attribute__((objc_nonlazy_class))
+@implementation E // expected-error {{prefix attribute must be followed by an interface or protocol}}
+@end