[all-commits] [llvm/llvm-project] 733d7c: [Debug] [Coroutines] Add deref operator for non co...

[Chuanqi Xu via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 733d7cf9649968c05f41480747ed91c7b0c3a82f
      https://github.com/llvm/llvm-project/commit/733d7cf9649968c05f41480747ed91c7b0c3a82f
  Author: Chuanqi Xu <yedeng.yd at linux.alibaba.com>
  Date:   2022-06-08 (Wed, 08 Jun 2022)

  Changed paths:
    M llvm/lib/Transforms/Coroutines/CoroFrame.cpp
    M llvm/test/Transforms/Coroutines/coro-debug-coro-frame.ll

  Log Message:
  -----------
  [Debug] [Coroutines] Add deref operator for non complex expression

Background:

When we construct coroutine frame, we would insert a dbg.declare
intrinsic for it:
```
%hdl = call void @llvm.coro.begin() ; would return coroutine handle
call void @llvm.dbg.declare(metadata ptr %hdl, metadata
![[DEBUG_VARIABLE: __coro_frame]], metadata !DIExpression())
```

And in the splitted coroutine, it looks like:
```
define void @coro_func.resume(ptr *hdl) {
entry.resume:
    call void @llvm.dbg.declare(metadata ptr %hdl, metadata
![[DEBUG_VARIABLE: __coro_frame]], metadata !DIExpression())
}
```

And we would salvage the debug info by inserting a new alloca here:
```
define void @coro_func.resume(ptr %hdl) {
entry.resume:
    %frame.debug = alloca ptr
    call void @llvm.dbg.declare(metadata ptr %frame.debug, metadata
![[DEBUG_VARIABLE: __coro_frame]], metadata !DIExpression())
    store ptr %hdl, %frame.debug
}
```

But now, the problem comes since the `dbg.declare` refers to the address
of that alloca instead of actual coroutine handle. I saw there are codes
to solve the problem but it only applies to complex expression only. I
feel if it is OK to relax the condition to make it work for
`__coro_frame`.

Reviewed By: jmorse

Differential Revision: https://reviews.llvm.org/D126277