[flang-commits] [flang] [flang] Avoid recursion in runtime derived type initialization (PR #102394)

[Slava Zakharin via flang-commits]

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@@ -0,0 +1,85 @@
+//===-- runtime/engine.cpp ------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "engine.h"
+#include "flang/Runtime/memory.h"
+
+namespace Fortran::runtime::engine {
+
+RT_API_ATTRS Engine::Work::Work(
+    Job job, const Descriptor &instance, const typeInfo::DerivedType *derived)
+    : job_{job}, u_{{instance}} {
+  auto &state{u_.commonState};
+  state.derived_ = derived;
+  state.elements_ = instance.Elements();
+  if (derived) {
+    state.componentDesc_ = &derived->component();
+    state.components_ = state.componentDesc_->Elements();
+  } else {
+    state.componentDesc_ = nullptr;
+    state.components_ = 0;
+  }
+}
+
+RT_API_ATTRS void Engine::Work::Resume(Engine &engine) {
+  switch (job_) {
+  case Job::Initialization:
+    u_.initialization.Resume(engine);
+    return;
+  }
+  engine.terminator().Crash(
+      "Work::Run: bad job_ code %d", static_cast<int>(job_));
+}
+
+RT_API_ATTRS Engine::~Engine() {
+  // deletes list owned by bottomWorkBlock_.next
+}
+
+RT_API_ATTRS int Engine::Do(
+    Job job, const Descriptor &instance, const typeInfo::DerivedType *derived) {
+  Begin(job, instance, derived);
+  while (topWorkBlock_ != &bottomWorkBlock_ && topWorkBlock_->depth > 0) {
----------------
vzakhari wrote:

Should this be `||`?

In the beginning `topWorkBlock_` is equal to `&bottomWorkBlock_`, so we will never enter this loop.

https://github.com/llvm/llvm-project/pull/102394