This revision was automatically updated to reflect the committed changes.
Closed by commit rC351461: [CodeGenObjC] Use a constant value for non-fragile
ivar offsets when possible (authored by epilk, committed by ).
Changed prior to commit:
https://reviews.llvm.org/D56802?vs=182214&id=182336#toc
Repository:
rC Clang
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D56802/new/
https://reviews.llvm.org/D56802
Files:
lib/CodeGen/CGObjCMac.cpp
test/CodeGenObjC/constant-non-fragile-ivar-offset.m
test/CodeGenObjC/optimize-ivar-offset-load.m
test/CodeGenObjC/reorder-synthesized-ivars.m
Index: lib/CodeGen/CGObjCMac.cpp
===================================================================
--- lib/CodeGen/CGObjCMac.cpp
+++ lib/CodeGen/CGObjCMac.cpp
@@ -1550,6 +1550,15 @@
return false;
}
+ bool isClassLayoutKnownStatically(const ObjCInterfaceDecl *ID) {
+ // NSObject is a fixed size. If we can see the @implementation of a class
+ // which inherits from NSObject then we know that all it's offsets also must
+ // be fixed. FIXME: Can we do this if see a chain of super classes with
+ // implementations leading to NSObject?
+ return ID->getImplementation() && ID->getSuperClass() &&
+ ID->getSuperClass()->getName() == "NSObject";
+ }
+
public:
CGObjCNonFragileABIMac(CodeGen::CodeGenModule &cgm);
@@ -6702,6 +6711,12 @@
IvarOffsetGV->setVisibility(llvm::GlobalValue::DefaultVisibility);
}
+ // If ID's layout is known, then make the global constant. This serves as a
+ // useful assertion: we'll never use this variable to calculate ivar offsets,
+ // so if the runtime tries to patch it then we should crash.
+ if (isClassLayoutKnownStatically(ID))
+ IvarOffsetGV->setConstant(true);
+
if (CGM.getTriple().isOSBinFormatMachO())
IvarOffsetGV->setSection("__DATA, __objc_ivar");
return IvarOffsetGV;
@@ -6990,17 +7005,24 @@
Offset);
}
-llvm::Value *CGObjCNonFragileABIMac::EmitIvarOffset(
- CodeGen::CodeGenFunction &CGF,
- const ObjCInterfaceDecl *Interface,
- const ObjCIvarDecl *Ivar) {
- llvm::Value *IvarOffsetValue = ObjCIvarOffsetVariable(Interface, Ivar);
- IvarOffsetValue = CGF.Builder.CreateAlignedLoad(IvarOffsetValue,
- CGF.getSizeAlign(), "ivar");
- if (IsIvarOffsetKnownIdempotent(CGF, Ivar))
- cast<llvm::LoadInst>(IvarOffsetValue)
- ->setMetadata(CGM.getModule().getMDKindID("invariant.load"),
- llvm::MDNode::get(VMContext, None));
+llvm::Value *
+CGObjCNonFragileABIMac::EmitIvarOffset(CodeGen::CodeGenFunction &CGF,
+ const ObjCInterfaceDecl *Interface,
+ const ObjCIvarDecl *Ivar) {
+ llvm::Value *IvarOffsetValue;
+ if (isClassLayoutKnownStatically(Interface)) {
+ IvarOffsetValue = llvm::ConstantInt::get(
+ ObjCTypes.IvarOffsetVarTy,
+ ComputeIvarBaseOffset(CGM, Interface->getImplementation(), Ivar));
+ } else {
+ llvm::GlobalVariable *GV = ObjCIvarOffsetVariable(Interface, Ivar);
+ IvarOffsetValue =
+ CGF.Builder.CreateAlignedLoad(GV, CGF.getSizeAlign(), "ivar");
+ if (IsIvarOffsetKnownIdempotent(CGF, Ivar))
+ cast<llvm::LoadInst>(IvarOffsetValue)
+ ->setMetadata(CGM.getModule().getMDKindID("invariant.load"),
+ llvm::MDNode::get(VMContext, None));
+ }
// This could be 32bit int or 64bit integer depending on the architecture.
// Cast it to 64bit integer value, if it is a 32bit integer ivar offset value
Index: test/CodeGenObjC/constant-non-fragile-ivar-offset.m
===================================================================
--- test/CodeGenObjC/constant-non-fragile-ivar-offset.m
+++ test/CodeGenObjC/constant-non-fragile-ivar-offset.m
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.14.0 -emit-llvm %s -o - | FileCheck %s
+
+// CHECK: @"OBJC_IVAR_$_StaticLayout.static_layout_ivar" = hidden constant i64 20
+// CHECK: @"OBJC_IVAR_$_NotStaticLayout.not_static_layout_ivar" = hidden global i64 12
+
+@interface NSObject {
+ int these, will, never, change, ever;
+}
+@end
+
+@interface StaticLayout : NSObject
+@end
+
+@implementation StaticLayout {
+ int static_layout_ivar;
+}
+-(void)meth {
+ static_layout_ivar = 0;
+ // CHECK-NOT: load i64, i64* @"OBJC_IVAR_$_StaticLayout
+}
+@end
+
+@interface NotNSObject {
+ int these, might, change;
+}
+@end
+
+@interface NotStaticLayout : NotNSObject
+@end
+
+@implementation NotStaticLayout {
+ int not_static_layout_ivar;
+}
+-(void)meth {
+ not_static_layout_ivar = 0;
+ // CHECK: load i64, i64* @"OBJC_IVAR_$_NotStaticLayout.not_static_layout_ivar
+}
+@end
Index: test/CodeGenObjC/optimize-ivar-offset-load.m
===================================================================
--- test/CodeGenObjC/optimize-ivar-offset-load.m
+++ test/CodeGenObjC/optimize-ivar-offset-load.m
@@ -1,17 +1,17 @@
// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -O0 -emit-llvm %s -o - | FileCheck %s
// rdar://16095748
-@interface NSObject
+@interface MyNSObject
@end
-@interface SampleClass : NSObject {
+@interface SampleClass : MyNSObject {
@public
int _value;
}
+ (SampleClass*) new;
@end
-@interface AppDelegate : NSObject
+@interface AppDelegate : MyNSObject
@end
extern void foo(int);
Index: test/CodeGenObjC/reorder-synthesized-ivars.m
===================================================================
--- test/CodeGenObjC/reorder-synthesized-ivars.m
+++ test/CodeGenObjC/reorder-synthesized-ivars.m
@@ -39,20 +39,20 @@
@end
// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean1
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean2
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean3
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean4
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean5
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean6
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean7
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean8
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean9
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object1
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object2
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object3
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object4
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object5
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object6
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object7
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object8
-// CHECK-NEXT: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object9
+// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean2
+// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean3
+// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean4
+// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean5
+// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean6
+// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean7
+// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean8
+// CHECK: @{{.*}} = private unnamed_addr constant [10 x i8] c"_boolean9
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object1
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object2
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object3
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object4
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object5
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object6
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object7
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object8
+// CHECK: @{{.*}} = private unnamed_addr constant [9 x i8] c"_object9
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