[coroutines] Use DILocation from new storage for hoisted dbg.declare #75402
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@llvm/pr-subscribers-llvm-transforms @llvm/pr-subscribers-coroutines Author: Wei Wang (apolloww) ChangesMake the hoisted dbg.declare inherent the DILocation scope from the new storage. After hoisting, the dbg.declare is moved into the block that defines the new storage. This could create an inconsistency in the debug location scope hierarchy where the scope of hoisted dbg.declare (i.e. DILexicalBlock) is enclosed with the scope of the block (i.e. DISubprogram). This confuses LiveDebugValues pass to think that the hoisted dbg.declare is killed in that block and does not generate DBG_VALUE in other blocks. Debugger won't be able to track its value anymore. We do this for unoptimized binary only. Full diff: https://github.com/llvm/llvm-project/pull/75402.diff 2 Files Affected:
diff --git a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
index f37b4dc938d304..529f7309a1a273 100644
--- a/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -2951,9 +2951,11 @@ void coro::salvageDebugInfo(
// dbg.declare does.
if (isa<DbgDeclareInst>(DVI)) {
std::optional<BasicBlock::iterator> InsertPt;
- if (auto *I = dyn_cast<Instruction>(Storage))
+ if (auto *I = dyn_cast<Instruction>(Storage)) {
InsertPt = I->getInsertionPointAfterDef();
- else if (isa<Argument>(Storage))
+ if (!OptimizeFrame && I->getDebugLoc())
+ DVI.setDebugLoc(I->getDebugLoc());
+ } else if (isa<Argument>(Storage))
InsertPt = F->getEntryBlock().begin();
if (InsertPt)
DVI.moveBefore(*(*InsertPt)->getParent(), *InsertPt);
diff --git a/llvm/test/Transforms/Coroutines/coro-debug-frame-variable.ll b/llvm/test/Transforms/Coroutines/coro-debug-frame-variable.ll
index 19a89fefd5269d..bf51218590c2f2 100644
--- a/llvm/test/Transforms/Coroutines/coro-debug-frame-variable.ll
+++ b/llvm/test/Transforms/Coroutines/coro-debug-frame-variable.ll
@@ -32,8 +32,8 @@
; CHECK: entry:
; CHECK: %j = alloca i32, align 4
; CHECK: call void @llvm.dbg.declare(metadata ptr %j, metadata ![[JVAR:[0-9]+]], metadata !DIExpression()), !dbg ![[JDBGLOC:[0-9]+]]
-; CHECK: %[[MEMORY:.*]] = call ptr @new
-; CHECK: call void @llvm.dbg.declare(metadata ptr %[[MEMORY]], metadata ![[XVAR:[0-9]+]], metadata !DIExpression(DW_OP_plus_uconst, 32)), !dbg ![[IDBGLOC:[0-9]+]]
+; CHECK: %[[MEMORY:.*]] = call ptr @new({{.+}}), !dbg ![[IDBGLOC:[0-9]+]]
+; CHECK: call void @llvm.dbg.declare(metadata ptr %[[MEMORY]], metadata ![[XVAR:[0-9]+]], metadata !DIExpression(DW_OP_plus_uconst, 32)), !dbg ![[IDBGLOC]]
; CHECK: call void @llvm.dbg.declare(metadata ptr %[[MEMORY]], metadata ![[IVAR:[0-9]+]], metadata !DIExpression(DW_OP_plus_uconst, 20)), !dbg ![[IDBGLOC]]
; CHECK: await.ready:
;
@@ -49,18 +49,20 @@
; CHECK: await.ready:
;
; CHECK-DAG: ![[IVAR]] = !DILocalVariable(name: "i"
-; CHECK-DAG: ![[SCOPE:[0-9]+]] = distinct !DILexicalBlock(scope: !6, file: !1, line: 23, column: 12)
-; CHECK-DAG: ![[IDBGLOC]] = !DILocation(line: 24, column: 7, scope: ![[SCOPE]])
+; CHECK-DAG: ![[PROG_SCOPE:[0-9]+]] = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov"
+; CHECK-DAG: ![[BLK_SCOPE:[0-9]+]] = distinct !DILexicalBlock(scope: ![[PROG_SCOPE]], file: !1, line: 23, column: 12)
+; CHECK-DAG: ![[IDBGLOC]] = !DILocation(line: 23, column: 6, scope: ![[PROG_SCOPE]])
; CHECK-DAG: ![[XVAR]] = !DILocalVariable(name: "x"
; CHECK-DAG: ![[JVAR]] = !DILocalVariable(name: "j"
-; CHECK-DAG: ![[JDBGLOC]] = !DILocation(line: 32, column: 7, scope: ![[SCOPE]])
+; CHECK-DAG: ![[JDBGLOC]] = !DILocation(line: 32, column: 7, scope: ![[BLK_SCOPE]])
; CHECK-DAG: ![[XVAR_RESUME]] = !DILocalVariable(name: "x"
-; CHECK-DAG: ![[IDBGLOC_RESUME]] = !DILocation(line: 24, column: 7, scope: ![[RESUME_SCOPE:[0-9]+]])
-; CHECK-DAG: ![[RESUME_SCOPE]] = distinct !DILexicalBlock(scope: !22, file: !1, line: 23, column: 12)
+; CHECK-DAG: ![[RESUME_PROG_SCOPE:[0-9]+]] = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov"
+; CHECK-DAG: ![[IDBGLOC_RESUME]] = !DILocation(line: 24, column: 7, scope: ![[RESUME_BLK_SCOPE:[0-9]+]])
+; CHECK-DAG: ![[RESUME_BLK_SCOPE]] = distinct !DILexicalBlock(scope: ![[RESUME_PROG_SCOPE]], file: !1, line: 23, column: 12)
; CHECK-DAG: ![[IVAR_RESUME]] = !DILocalVariable(name: "i"
; CHECK-DAG: ![[JVAR_RESUME]] = !DILocalVariable(name: "j"
-; CHECK-DAG: ![[JDBGLOC_RESUME]] = !DILocation(line: 32, column: 7, scope: ![[RESUME_SCOPE]])
+; CHECK-DAG: ![[JDBGLOC_RESUME]] = !DILocation(line: 32, column: 7, scope: ![[RESUME_BLK_SCOPE]])
define void @f() presplitcoroutine !dbg !8 {
entry:
%__promise = alloca i8, align 8
@@ -72,13 +74,13 @@ entry:
br i1 %alloc, label %coro.alloc, label %coro.init
coro.alloc: ; preds = %entry
- %size = call i64 @llvm.coro.size.i64()
- %memory = call ptr @new(i64 %size)
- br label %coro.init
+ %size = call i64 @llvm.coro.size.i64(), !dbg !23
+ %memory = call ptr @new(i64 %size), !dbg !23
+ br label %coro.init, !dbg !23
coro.init: ; preds = %coro.alloc, %entry
- %phi.entry.alloc = phi ptr [ null, %entry ], [ %memory, %coro.alloc ]
- %begin = call ptr @llvm.coro.begin(token %id, ptr %phi.entry.alloc)
+ %phi.entry.alloc = phi ptr [ null, %entry ], [ %memory, %coro.alloc ], !dbg !23
+ %begin = call ptr @llvm.coro.begin(token %id, ptr %phi.entry.alloc), !dbg !23
%ready = call i1 @await_ready()
br i1 %ready, label %init.ready, label %init.suspend
@@ -240,3 +242,4 @@ declare void @llvm.memset.p0.i64(ptr nocapture writeonly, i8, i64, i1 immarg)
!20 = !DILocation(line: 43, column: 3, scope: !7)
!21 = !DILocation(line: 43, column: 8, scope: !7)
!22 = distinct !DILexicalBlock(scope: !8, file: !1, line: 23, column: 12)
+!23 = !DILocation(line: 23, column: 6, scope: !8)
|
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Reland #75104. It was reverted because after inlining, we could be hoisting variables from callee which causes mis-match of |
|
It would be great if we would add a test case from that reproducer here. We could start from the IR clang generates, and run llvm-reduce on that. |
Sure. I'll add the repro to test. |
ChuanqiXu9
approved these changes
Dec 20, 2023
| InsertPt = I->getInsertionPointAfterDef(); | ||
| else if (isa<Argument>(Storage)) | ||
| if (!OptimizeFrame && I->getDebugLoc()) |
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Suggested change
| if (!OptimizeFrame && I->getDebugLoc()) | |
| // Don't hoist debug intrinsics since it is easy to get out of sync in optimizations. | |
| // See https://github.com/llvm/llvm-project/pull/75104 for an example. | |
| if (!OptimizeFrame && I->getDebugLoc()) |
nit
zyx-billy
added a commit
that referenced
this pull request
May 23, 2024
…level for hoisted DbgDeclare Loc (#92978) Minor patch following up on #75402. The more generalized version of [this error](#75104 (comment)) is whenever we have a debug variable created in one subprogram scope inlined into another subprogram scope. So instead of checking optimization level, it is safer to just check whether the subprogram scope of the variable matches the subprogram scope of the hoisted position.
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Make the hoisted dbg.declare inherent the DILocation scope from the new storage.
After hoisting, the dbg.declare is moved into the block that defines the new storage. This could create an inconsistency in the debug location scope hierarchy where the scope of hoisted dbg.declare (i.e. DILexicalBlock) is enclosed with the scope of the block (i.e. DISubprogram). This confuses LiveDebugValues pass to think that the hoisted dbg.declare is killed in that block and does not generate DBG_VALUE in other blocks. Debugger won't be able to track its value anymore.
We do this for unoptimized binary only.