[coroutines] Use DILocation from new storage for hoisted dbg.declare (#75104)

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.

Author: apolloww

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

@@ -2891,9 +2891,11 @@ 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 (I->getDebugLoc())
+        DVI->setDebugLoc(I->getDebugLoc());
+    } else if (isa<Argument>(Storage))
       InsertPt = F->getEntryBlock().begin();
     if (InsertPt)
       DVI->moveBefore(*(*InsertPt)->getParent(), *InsertPt);

llvm/test/Transforms/Coroutines/coro-debug-frame-variable.ll

@@ -31,8 +31,8 @@
 ; 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:
 ;
@@ -48,18 +48,20 @@
 ; 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
@@ -71,13 +73,13 @@ 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
 
@@ -239,3 +241,4 @@ 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)