maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[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
This commit is contained in:
Chuanqi Xu 2022-05-24 14:09:18 +08:00
parent 9b3c5cba9f
commit 733d7cf964
2 changed files with 4 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
llvm/lib/Transforms/Coroutines/CoroFrame.cpp
View File

@ -2564,6 +2564,7 @@ void coro::salvageDebugInfo(
bool SkipOutermostLoad = !isa<DbgValueInst>(DVI);
Value *Storage = DVI->getVariableLocationOp(0);
Value *OriginalStorage = Storage;
while (auto *Inst = dyn_cast_or_null<Instruction>(Storage)) {
if (auto *LdInst = dyn_cast<LoadInst>(Inst)) {
Storage = LdInst->getOperand(0);
@ -2619,8 +2620,7 @@ void coro::salvageDebugInfo(
// expression, we need to add a DW_OP_deref at the *start* of the
// expression to first load the contents of the alloca before
// adjusting it with the expression.
if (Expr && Expr->isComplex())
Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
}
DVI->replaceVariableLocationOp(OriginalStorage, Storage);

3
llvm/test/Transforms/Coroutines/coro-debug-coro-frame.ll
View File

@ -10,7 +10,8 @@
;
; CHECK: define internal fastcc void @f.resume(
; CHECK: entry.resume:
; CHECK: call void @llvm.dbg.declare(metadata %f.Frame** %[[FramePtr_RESUME:.*]], metadata ![[CORO_FRAME_IN_RESUME:[0-9]+]], metadata !DIExpression()
; CHECK: %[[FramePtr_RESUME:.*]] = alloca %f.Frame*
; CHECK: call void @llvm.dbg.declare(metadata %f.Frame** %[[FramePtr_RESUME]], metadata ![[CORO_FRAME_IN_RESUME:[0-9]+]], metadata !DIExpression(DW_OP_deref)
;
; CHECK-DAG: ![[FILE:[0-9]+]] = !DIFile(filename: "coro-debug.cpp"
; CHECK-DAG: ![[RAMP:[0-9]+]] = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov",