Merge pull request #34977 from slavapestov/nonoverridden-descriptors

IRGen: Nonoverridden method descriptors should be true-const

Author: slavapestov

lib/IRGen/GenMeta.cpp

@@ -301,12 +301,16 @@ static void buildMethodDescriptorFields(IRGenModule &IGM,
 void IRGenModule::emitNonoverriddenMethodDescriptor(const SILVTable *VTable,
                                                     SILDeclRef declRef) {
   auto entity = LinkEntity::forMethodDescriptor(declRef);
-  auto *var = cast<llvm::GlobalVariable>(getAddrOfLLVMVariable(entity, ConstantInit(), DebugTypeInfo()));
+  auto *var = cast<llvm::GlobalVariable>(
+      getAddrOfLLVMVariable(entity, ConstantInit(), DebugTypeInfo()));
   if (!var->isDeclaration()) {
     assert(IRGen.isLazilyReemittingNominalTypeDescriptor(VTable->getClass()));
     return;
   }
 
+  var->setConstant(true);
+  setTrueConstGlobal(var);
+
   ConstantInitBuilder ib(*this);
   ConstantStructBuilder sb(ib.beginStruct(MethodDescriptorStructTy));
 

test/IRGen/vtable_non_overridden.sil

@@ -25,8 +25,8 @@ sil_vtable InternalA {
 }
 
 // -- we should still generate method descriptors for the elided methods
-// CHECK-LABEL: @"$s21vtable_non_overridden9InternalAC3fooyyFTq" =
-// CHECK-LABEL: @"$s21vtable_non_overridden9InternalAC3basyyFTq" =
+// CHECK-LABEL: @"$s21vtable_non_overridden9InternalAC3fooyyFTq" = hidden constant %swift.method_descriptor {{.*}} section "{{(__TEXT,__const|\.rodata|\.rdata)}}"
+// CHECK-LABEL: @"$s21vtable_non_overridden9InternalAC3basyyFTq" = hidden constant %swift.method_descriptor {{.*}} section "{{(__TEXT,__const|\.rodata|\.rdata)}}"
 
 // -- only overridden entries in internal method descriptor table
 // CHECK-LABEL: @"$s21vtable_non_overridden9InternalACMn" =