[CIR][CIRGen] Lower cir.throw in absence of dtors

Author: bcardosolopes

clang/include/clang/CIR/MissingFeatures.h

@@ -103,7 +103,7 @@ struct MissingFeatures {
   static bool shouldCreateMemCpyFromGlobal() { return false; }
   static bool shouldReverseUnaryCondOnBoolExpr() { return false; }
   static bool fieldMemcpyizerBuildMemcpy() { return false; }
-  static bool isTrivialAndisDefaultConstructor() { return false; }
+  static bool isTrivialCtorOrDtor() { return false; }
   static bool isMemcpyEquivalentSpecialMember() { return false; }
   static bool constructABIArgDirectExtend() { return false; }
   static bool mayHaveIntegerOverflow() { return false; }

clang/lib/CIR/CodeGen/CIRGenFunction.cpp

@@ -814,7 +814,7 @@ void CIRGenFunction::buildCXXConstructorCall(
   // In LLVM: do nothing.
   // In CIR: emit as a regular call, other later passes should lower the
   // ctor call into trivial initialization.
-  assert(!MissingFeatures::isTrivialAndisDefaultConstructor());
+  assert(!MissingFeatures::isTrivialCtorOrDtor());
 
   if (isMemcpyEquivalentSpecialMember(D)) {
     assert(!MissingFeatures::isMemcpyEquivalentSpecialMember());

clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp

@@ -2210,16 +2210,19 @@ void CIRGenItaniumCXXABI::buildThrow(CIRGenFunction &CGF,
   // LoweringPrepare or some other pass to skip passing the
   // trivial function.
   //
-  // TODO(cir): alternatively, dtor could be ignored here and
-  // the type used to gather the relevant dtor during
-  // LoweringPrepare.
+  // TODO(cir): However, such lowering is still NYI, and for
+  // the sake of getting cir.throw right, the same OG path is
+  // follows here.
   mlir::FlatSymbolRefAttr dtor{};
   if (const RecordType *recordTy = clangThrowType->getAs<RecordType>()) {
     CXXRecordDecl *rec = cast<CXXRecordDecl>(recordTy->getDecl());
-    CXXDestructorDecl *dtorD = rec->getDestructor();
-    dtor = mlir::FlatSymbolRefAttr::get(
-        CGM.getAddrOfCXXStructor(GlobalDecl(dtorD, Dtor_Complete))
-            .getSymNameAttr());
+    assert(!MissingFeatures::isTrivialCtorOrDtor());
+    if (!rec->hasTrivialDestructor()) {
+      CXXDestructorDecl *dtorD = rec->getDestructor();
+      dtor = mlir::FlatSymbolRefAttr::get(
+          CGM.getAddrOfCXXStructor(GlobalDecl(dtorD, Dtor_Complete))
+              .getSymNameAttr());
+    }
   }
 
   // FIXME: When adding support for invoking, we should wrap the throw op

clang/test/CIR/CodeGen/eh.cpp

@@ -0,0 +1,31 @@
+// RUN: %clang_cc1 -std=c++20 -triple aarch64-none-linux-android21 -fclangir -fcxx-exceptions -fexceptions -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CIR
+// RUN: %clang_cc1 -std=c++20 -triple aarch64-none-linux-android21 -fclangir -fcxx-exceptions -fexceptions -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=LLVM
+
+struct test1_D {
+  double d;
+} d1;
+
+void test1() {
+  throw d1;
+}
+
+// CIR-LABEL: @_Z5test1v
+// FIXME: this is overaligned, should be 4.
+// CIR:   %[[ALLOC:.*]] = cir.alloc.exception 8 -> !cir.ptr<!ty_test1_D>
+// CIR:   %[[G:.*]] = cir.get_global @d1 : !cir.ptr<!ty_test1_D>
+// CIR:   cir.call @_ZN7test1_DC1ERKS_(%[[ALLOC]], %[[G]]) : (!cir.ptr<!ty_test1_D>, !cir.ptr<!ty_test1_D>) -> ()
+// CIR:   cir.throw %[[ALLOC]] : !cir.ptr<!ty_test1_D>, @_ZTI7test1_D
+// CIR:   cir.unreachable
+// CIR: }
+
+// LLVM-LABEL: @_Z5test1v
+// FIXME: this is overaligned, should be 4.
+// LLVM:   %[[ALLOC:.*]] = call ptr @__cxa_allocate_exception(i64 8)
+
+// FIXME: this is a simple store once we fix isTrivialCtorOrDtor().
+// LLVM:   call void @_ZN7test1_DC1ERKS_(ptr %[[ALLOC]], ptr @d1)
+// LLVM:   call void @__cxa_throw(ptr %[[ALLOC]], ptr @_ZTI7test1_D, ptr null)
+// LLVM:   unreachable
+// LLVM: }