[PATCH] D86185: [Cloning] Fix to cloning DISubprograms.

[David Blaikie via Phabricator via llvm-commits]

dblaikie added inline comments.


================
Comment at: llvm/unittests/Transforms/Utils/CloningTest.cpp:740-744
+    !3 = distinct !DISubprogram(name: "my_operator", scope: !1, retainedNodes: !{!5})
+    !4 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !3)
+    !5 = !DILocalVariable(name: "awaitables", scope: !3)
+    !6 = distinct !DISubprogram(name: "test", scope: !1, retainedNodes: !{!7})
+    !7 = !DILocalVariable(name: "w", scope: !6, type: !4)
----------------
akhuang wrote:
> dblaikie wrote:
> > This debug info metadata looks like it has two cycles (my_operator -> awaitables -> my_operator and test -> w -> test). Are they both necessary? do they both test different cases? Might be worth a few more words in the test comment above about what they're exercising/what aspects of them are relevant/necessary to reproduce the issue?
> I don't think either is necessary, actually. The important part for reproducing is just that there's a path from test -> my_operator. Maybe I can get rid of some  more stuff; this is just what the metadata happened to look like in the repro. 
Ah, so the critical path is "test" -> "w" -> anonymous type (!4) -> "my_operator" ?

I guess this could happen in real-world non-coroutine code with templates like this:
```
template<typename T>
void f1() {
  T t;
}
void f2() {
  struct x { };
  f1<x>();
}
```
(compiled with optimizations (well, might have to add noinline or optnone to 'f1' to get it through optimizations) that should produce 't' in 'f1's retained types list, etc)

In any case, yeah - documenting that chain & trimming down anything else (I guess removing "awaitables"/removing "my_operator"s retainedNodes list) would be good


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D86185/new/

https://reviews.llvm.org/D86185