Skip to content

[clang][CGObjC] Sign the v-table pointer in ObjC exception RTTI. #135562

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 7 commits into from
Closed

[clang][CGObjC] Sign the v-table pointer in ObjC exception RTTI. #135562

Show file tree
Hide file tree
Changes from 6 commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
5dc1e5f
[clang][CGObjC] Sign the v-table pointer in ObjC exception RTTI.
ojhunt Apr 13, 2025
fadf7d8
Merge remote-tracking branch 'origin/main' into users/ojhunt/objc-cor…
ojhunt Jun 4, 2025
b688c00
Merge remote-tracking branch 'origin/main' into users/ojhunt/objc-cor…
ojhunt Jun 4, 2025
6454572
Merge remote-tracking branch 'origin/main' into users/ojhunt/objc-cor…
ojhunt Jun 4, 2025
8db3653
Switch to Schema addSignedPointer API, remove the exploded version, a…
ojhunt Jun 4, 2025
252ff4d
reformatting
ojhunt Jun 4, 2025
86a6d7f
Update clang/docs/ReleaseNotes.rst
ojhunt Jun 4, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions clang/docs/ReleaseNotes.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -317,6 +317,7 @@ Non-comprehensive list of changes in this release
``sizeof`` or ``typeof`` expression. (#GH138444)
- Deprecation warning is emitted for the deprecated ``__reference_binds_to_temporary`` intrinsic.
``__reference_constructs_from_temporary`` should be used instead. (#GH44056)
- Support authenticated ``type_info`` vtable pointers in Objective-C++

New Compiler Flags
------------------
Expand Down
15 changes: 13 additions & 2 deletions clang/lib/CodeGen/CGObjCMac.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7676,10 +7676,21 @@ CGObjCNonFragileABIMac::GetInterfaceEHType(const ObjCInterfaceDecl *ID,
}

llvm::Value *VTableIdx = llvm::ConstantInt::get(CGM.Int32Ty, 2);
llvm::Constant *VTablePtr = llvm::ConstantExpr::getInBoundsGetElementPtr(
VTableGV->getValueType(), VTableGV, VTableIdx);

ConstantInitBuilder builder(CGM);
auto values = builder.beginStruct(ObjCTypes.EHTypeTy);
values.add(llvm::ConstantExpr::getInBoundsGetElementPtr(
VTableGV->getValueType(), VTableGV, VTableIdx));

if (auto &Schema =
CGM.getCodeGenOpts().PointerAuth.CXXTypeInfoVTablePointer) {
assert(!Schema.hasOtherDiscrimination() ||
Schema.getOtherDiscrimination() ==
PointerAuthSchema::Discrimination::Constant);
values.addSignedPointer(VTablePtr, Schema, GlobalDecl(), QualType());
} else {
values.add(VTablePtr);
}
values.add(GetClassName(ClassName));
values.add(GetClassGlobal(ID, /*metaclass*/ false, NotForDefinition));

Expand Down
18 changes: 18 additions & 0 deletions clang/test/CodeGenObjC/ptrauth-attr-exception.m
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
// RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-calls -emit-llvm -fexceptions -fobjc-exceptions -o - %s | FileCheck %s
// RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-type-info-vtable-pointer-discrimination -fptrauth-calls -emit-llvm -fexceptions -fobjc-exceptions -o - %s | FileCheck --check-prefix=TYPEDISC_TYPEINFO %s

__attribute__((objc_root_class))
@interface Root {
Class isa;
}
@end

__attribute__((objc_exception))
@interface A : Root
@end

@implementation A
@end

// CHECK: @"OBJC_EHTYPE_$_A" = global {{%.*}} { ptr ptrauth (ptr getelementptr inbounds (ptr, ptr @objc_ehtype_vtable, i32 2), i32 2),
// TYPEDISC_TYPEINFO: @"OBJC_EHTYPE_$_A" = global {{%.*}} { ptr ptrauth (ptr getelementptr inbounds (ptr, ptr @objc_ehtype_vtable, i32 2), i32 2, i64 45546, ptr @"OBJC_EHTYPE_$_A"),
Loading