[clang] dd9f796 - [ObjC] avoid crashing when emitting synthesized getter/setter and ptrdiff_t is smaller than long

[Matt Jacobson via cfe-commits]

Author: Matt Jacobson
Date: 2022-11-10T02:10:30-05:00
New Revision: dd9f7963e434a53e8d70f607392ee9abf76f1d99

URL: https://github.com/llvm/llvm-project/commit/dd9f7963e434a53e8d70f607392ee9abf76f1d99
DIFF: https://github.com/llvm/llvm-project/commit/dd9f7963e434a53e8d70f607392ee9abf76f1d99.diff

LOG: [ObjC] avoid crashing when emitting synthesized getter/setter and ptrdiff_t is smaller than long

On targets where ptrdiff_t is smaller than long, clang crashes when emitting
synthesized getters/setters that call objc_[gs]etProperty.  Explicitly emit a
zext/trunc of the ivar offset value (which is defined to long) to ptrdiff_t,
which objc_[gs]etProperty takes.

Add a test using the AVR target, where ptrdiff_t is smaller than long. Test
failed previously and passes now.

Differential Revision: https://reviews.llvm.org/D112049

Added: 
    clang/test/CodeGen/avr/objc-property.m

Modified: 
    clang/lib/CodeGen/CGExpr.cpp
    clang/lib/CodeGen/CGObjC.cpp
    clang/lib/CodeGen/CodeGenFunction.h

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 40d9b8f37b4a6..ee09a8566c371 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -5242,6 +5242,15 @@ llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
   return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
 }
 
+llvm::Value *
+CodeGenFunction::EmitIvarOffsetAsPointerDiff(const ObjCInterfaceDecl *Interface,
+                                             const ObjCIvarDecl *Ivar) {
+  llvm::Value *OffsetValue = EmitIvarOffset(Interface, Ivar);
+  QualType PointerDiffType = getContext().getPointerDiffType();
+  return Builder.CreateZExtOrTrunc(OffsetValue,
+                                   getTypes().ConvertType(PointerDiffType));
+}
+
 LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
                                           llvm::Value *BaseValue,
                                           const ObjCIvarDecl *Ivar,

diff  --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index 5ec2fdb5c1708..3eb530d3e9417 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -1228,7 +1228,7 @@ CodeGenFunction::generateObjCGetterBody(const ObjCImplementationDecl *classImpl,
     llvm::Value *cmd = emitCmdValueForGetterSetterBody(*this, getterMethod);
     llvm::Value *self = Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
     llvm::Value *ivarOffset =
-      EmitIvarOffset(classImpl->getClassInterface(), ivar);
+        EmitIvarOffsetAsPointerDiff(classImpl->getClassInterface(), ivar);
 
     CallArgList args;
     args.add(RValue::get(self), getContext().getObjCIdType());
@@ -1532,7 +1532,7 @@ CodeGenFunction::generateObjCSetterBody(const ObjCImplementationDecl *classImpl,
     llvm::Value *self =
       Builder.CreateBitCast(LoadObjCSelf(), VoidPtrTy);
     llvm::Value *ivarOffset =
-      EmitIvarOffset(classImpl->getClassInterface(), ivar);
+        EmitIvarOffsetAsPointerDiff(classImpl->getClassInterface(), ivar);
     Address argAddr = GetAddrOfLocalVar(*setterMethod->param_begin());
     llvm::Value *arg = Builder.CreateLoad(argAddr, "arg");
     arg = Builder.CreateBitCast(arg, VoidPtrTy);

diff  --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 05e5bad21d46f..7ef22eb064efd 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -3974,6 +3974,8 @@ class CodeGenFunction : public CodeGenTypeCache {
 
   llvm::Value *EmitIvarOffset(const ObjCInterfaceDecl *Interface,
                               const ObjCIvarDecl *Ivar);
+  llvm::Value *EmitIvarOffsetAsPointerDiff(const ObjCInterfaceDecl *Interface,
+                                           const ObjCIvarDecl *Ivar);
   LValue EmitLValueForField(LValue Base, const FieldDecl* Field);
   LValue EmitLValueForLambdaField(const FieldDecl *Field);
 

diff  --git a/clang/test/CodeGen/avr/objc-property.m b/clang/test/CodeGen/avr/objc-property.m
new file mode 100644
index 0000000000000..a3eaea2e0375a
--- /dev/null
+++ b/clang/test/CodeGen/avr/objc-property.m
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -triple avr -emit-llvm -fobjc-runtime=macosx %s -o /dev/null
+
+__attribute__((objc_root_class))
+ at interface Foo
+
+ at property(strong) Foo *f;
+
+ at end
+
+ at implementation Foo
+
+ at synthesize f = _f;
+
+ at end