[cfe-commits] r166088 - in /cfe/trunk: include/clang/AST/DeclObjC.h lib/CodeGen/CGObjCMac.cpp lib/CodeGen/CodeGenModule.cpp lib/Serialization/ASTReaderDecl.cpp lib/Serialization/ASTWriterDecl.cpp test/CodeGenObjC/arc.m
John McCall
rjmccall at apple.com
Tue Oct 16 21:53:31 PDT 2012
Author: rjmccall
Date: Tue Oct 16 23:53:31 2012
New Revision: 166088
URL: http://llvm.org/viewvc/llvm-project?rev=166088&view=rev
Log:
Set a special flag in class metadata when an Objective-C class
has ivars that require destruction, but none that require anything
except zero-initialization. This is common in ARC and (when true
throughout a class hierarchy) permits the elimination of an
unnecessary message-send during allocation.
Modified:
cfe/trunk/include/clang/AST/DeclObjC.h
cfe/trunk/lib/CodeGen/CGObjCMac.cpp
cfe/trunk/lib/CodeGen/CodeGenModule.cpp
cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
cfe/trunk/lib/Serialization/ASTWriterDecl.cpp
cfe/trunk/test/CodeGenObjC/arc.m
Modified: cfe/trunk/include/clang/AST/DeclObjC.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclObjC.h?rev=166088&r1=166087&r2=166088&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/DeclObjC.h (original)
+++ cfe/trunk/include/clang/AST/DeclObjC.h Tue Oct 16 23:53:31 2012
@@ -1581,8 +1581,12 @@
CXXCtorInitializer **IvarInitializers;
unsigned NumIvarInitializers;
- /// true if class has a .cxx_[construct,destruct] method.
- bool HasCXXStructors : 1;
+ /// Do the ivars of this class require initialization other than
+ /// zero-initialization?
+ bool HasNonZeroConstructors : 1;
+
+ /// Do the ivars of this class require non-trivial destruction?
+ bool HasDestructors : 1;
ObjCImplementationDecl(DeclContext *DC,
ObjCInterfaceDecl *classInterface,
@@ -1594,7 +1598,7 @@
SuperClass(superDecl), IvarLBraceLoc(IvarLBraceLoc),
IvarRBraceLoc(IvarRBraceLoc),
IvarInitializers(0), NumIvarInitializers(0),
- HasCXXStructors(false) {}
+ HasNonZeroConstructors(false), HasDestructors(false) {}
public:
static ObjCImplementationDecl *Create(ASTContext &C, DeclContext *DC,
ObjCInterfaceDecl *classInterface,
@@ -1638,8 +1642,15 @@
CXXCtorInitializer ** initializers,
unsigned numInitializers);
- bool hasCXXStructors() const { return HasCXXStructors; }
- void setHasCXXStructors(bool val) { HasCXXStructors = val; }
+ /// Do any of the ivars of this class (not counting its base classes)
+ /// require construction other than zero-initialization?
+ bool hasNonZeroConstructors() const { return HasNonZeroConstructors; }
+ void setHasNonZeroConstructors(bool val) { HasNonZeroConstructors = val; }
+
+ /// Do any of the ivars of this class (not counting its base classes)
+ /// require non-trivial destruction?
+ bool hasDestructors() const { return HasDestructors; }
+ void setHasDestructors(bool val) { HasDestructors = val; }
/// getIdentifier - Get the identifier that names the class
/// interface associated with this implementation.
Modified: cfe/trunk/lib/CodeGen/CGObjCMac.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjCMac.cpp?rev=166088&r1=166087&r2=166088&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGObjCMac.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGObjCMac.cpp Tue Oct 16 23:53:31 2012
@@ -2367,7 +2367,10 @@
NonFragileABI_Class_HasIvarReleaser = 0x00040,
/// Class implementation was compiled under ARC.
- NonFragileABI_Class_CompiledByARC = 0x00080
+ NonFragileABI_Class_CompiledByARC = 0x00080,
+
+ /// Class has non-trivial destructors, but zero-initialization is okay.
+ NonFragileABI_Class_HasCXXDestructorOnly = 0x00100
};
/*
@@ -2401,7 +2404,7 @@
Interface->all_referenced_protocol_begin(),
Interface->all_referenced_protocol_end());
unsigned Flags = FragileABI_Class_Factory;
- if (ID->hasCXXStructors())
+ if (ID->hasNonZeroConstructors() || ID->hasDestructors())
Flags |= FragileABI_Class_HasCXXStructors;
unsigned Size =
CGM.getContext().getASTObjCImplementationLayout(ID).getSize().getQuantity();
@@ -5154,12 +5157,20 @@
llvm::GlobalVariable *SuperClassGV, *IsAGV;
+ // Build the flags for the metaclass.
bool classIsHidden =
ID->getClassInterface()->getVisibility() == HiddenVisibility;
if (classIsHidden)
flags |= NonFragileABI_Class_Hidden;
- if (ID->hasCXXStructors())
+
+ // FIXME: why is this flag set on the metaclass?
+ // ObjC metaclasses have no fields and don't really get constructed.
+ if (ID->hasNonZeroConstructors() || ID->hasDestructors()) {
flags |= NonFragileABI_Class_HasCXXStructors;
+ if (!ID->hasNonZeroConstructors())
+ flags |= NonFragileABI_Class_HasCXXDestructorOnly;
+ }
+
if (!ID->getClassInterface()->getSuperClass()) {
// class is root
flags |= NonFragileABI_Class_Root;
@@ -5194,9 +5205,20 @@
flags = 0;
if (classIsHidden)
flags |= NonFragileABI_Class_Hidden;
- if (ID->hasCXXStructors())
+
+ if (ID->hasNonZeroConstructors() || ID->hasDestructors()) {
flags |= NonFragileABI_Class_HasCXXStructors;
+ // Set a flag to enable a runtime optimization when a class has
+ // fields that require destruction but which don't require
+ // anything except zero-initialization during construction. This
+ // is most notably true of __strong and __weak types, but you can
+ // also imagine there being C++ types with non-trivial default
+ // constructors that merely set all fields to null.
+ if (!ID->hasNonZeroConstructors())
+ flags |= NonFragileABI_Class_HasCXXDestructorOnly;
+ }
+
if (hasObjCExceptionAttribute(CGM.getContext(), ID->getClassInterface()))
flags |= NonFragileABI_Class_Exception;
Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.cpp?rev=166088&r1=166087&r2=166088&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenModule.cpp (original)
+++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp Tue Oct 16 23:53:31 2012
@@ -2541,7 +2541,7 @@
/*isDefined=*/false, ObjCMethodDecl::Required);
D->addInstanceMethod(DTORMethod);
CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false);
- D->setHasCXXStructors(true);
+ D->setHasDestructors(true);
}
// If the implementation doesn't have any ivar initializers, we don't need
@@ -2565,7 +2565,7 @@
ObjCMethodDecl::Required);
D->addInstanceMethod(CTORMethod);
CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true);
- D->setHasCXXStructors(true);
+ D->setHasNonZeroConstructors(true);
}
/// EmitNamespace - Emit all declarations in a namespace.
Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderDecl.cpp?rev=166088&r1=166087&r2=166088&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTReaderDecl.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Tue Oct 16 23:53:31 2012
@@ -855,6 +855,8 @@
D->setSuperClass(ReadDeclAs<ObjCInterfaceDecl>(Record, Idx));
D->setIvarLBraceLoc(ReadSourceLocation(Record, Idx));
D->setIvarRBraceLoc(ReadSourceLocation(Record, Idx));
+ D->setHasNonZeroConstructors(Record[Idx++]);
+ D->setHasDestructors(Record[Idx++]);
llvm::tie(D->IvarInitializers, D->NumIvarInitializers)
= Reader.ReadCXXCtorInitializers(F, Record, Idx);
}
Modified: cfe/trunk/lib/Serialization/ASTWriterDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriterDecl.cpp?rev=166088&r1=166087&r2=166088&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTWriterDecl.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTWriterDecl.cpp Tue Oct 16 23:53:31 2012
@@ -606,6 +606,8 @@
Writer.AddDeclRef(D->getSuperClass(), Record);
Writer.AddSourceLocation(D->getIvarLBraceLoc(), Record);
Writer.AddSourceLocation(D->getIvarRBraceLoc(), Record);
+ Record.push_back(D->hasNonZeroConstructors());
+ Record.push_back(D->hasDestructors());
Writer.AddCXXCtorInitializers(D->IvarInitializers, D->NumIvarInitializers,
Record);
Code = serialization::DECL_OBJC_IMPLEMENTATION;
Modified: cfe/trunk/test/CodeGenObjC/arc.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjC/arc.m?rev=166088&r1=166087&r2=166088&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenObjC/arc.m (original)
+++ cfe/trunk/test/CodeGenObjC/arc.m Tue Oct 16 23:53:31 2012
@@ -602,7 +602,10 @@
// rdar://problem/8922540
// Note that we no longer emit .release_ivars flags.
-// CHECK-GLOBALS: @"\01l_OBJC_CLASS_RO_$_Test23" = internal global [[RO_T:%.*]] { i32 134,
+// rdar://problem/12492434
+// Note that we set the flag saying that we need destruction *and*
+// the flag saying that we don't also need construction.
+// CHECK-GLOBALS: @"\01l_OBJC_CLASS_RO_$_Test23" = internal global [[RO_T:%.*]] { i32 390,
@interface Test23 { id x; } @end
@implementation Test23 @end
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