[flang-commits] [flang] [flang][debug] Set scope of internal functions correctly. (PR #99531)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-fir-hlfir

Author: Abid Qadeer (abidh)

<details>
<summary>Changes</summary>

The functions internal to subroutine should have the scope set to the parent function. This allows a user to evaluate local variables of parent function when control is stopped in the child.

Fixes #<!-- -->96314

---
Full diff: https://github.com/llvm/llvm-project/pull/99531.diff


2 Files Affected:

- (modified) flang/lib/Optimizer/Transforms/AddDebugInfo.cpp (+21-1) 
- (added) flang/test/Transforms/debug-96314.fir (+26) 


``````````diff
diff --git a/flang/lib/Optimizer/Transforms/AddDebugInfo.cpp b/flang/lib/Optimizer/Transforms/AddDebugInfo.cpp
index 8bb24fb6c8078..7c9555dd737ab 100644
--- a/flang/lib/Optimizer/Transforms/AddDebugInfo.cpp
+++ b/flang/lib/Optimizer/Transforms/AddDebugInfo.cpp
@@ -299,9 +299,29 @@ void AddDebugInfoPass::runOnOperation() {
           subprogramFlags | mlir::LLVM::DISubprogramFlags::Definition;
     }
     unsigned line = getLineFromLoc(l);
-    if (!result.second.modules.empty())
+    if (fir::isInternalProcedure(funcOp)) {
+      // For contained functions, the scope is the parent subroutine.
+      mlir::SymbolRefAttr sym = mlir::cast<mlir::SymbolRefAttr>(
+          funcOp->getAttr(fir::getHostSymbolAttrName()));
+      if (sym) {
+        if (auto func = symbolTable.lookup<mlir::func::FuncOp>(
+                sym.getLeafReference())) {
+          // FIXME: Can there be situation where we process contained function
+          // before the parent?
+          if (debugInfoIsAlreadySet(func.getLoc())) {
+            if (auto fusedLoc = mlir::cast<mlir::FusedLoc>(func.getLoc())) {
+              if (auto spAttr =
+                      mlir::dyn_cast_if_present<mlir::LLVM::DISubprogramAttr>(
+                          fusedLoc.getMetadata()))
+                Scope = spAttr;
+            }
+          }
+        }
+      }
+    } else if (!result.second.modules.empty()) {
       Scope = getOrCreateModuleAttr(result.second.modules[0], fileAttr, cuAttr,
                                     line - 1, false);
+    }
 
     auto spAttr = mlir::LLVM::DISubprogramAttr::get(
         context, id, compilationUnit, Scope, funcName, fullName, funcFileAttr,
diff --git a/flang/test/Transforms/debug-96314.fir b/flang/test/Transforms/debug-96314.fir
new file mode 100644
index 0000000000000..e2d0f24a1105c
--- /dev/null
+++ b/flang/test/Transforms/debug-96314.fir
@@ -0,0 +1,26 @@
+// RUN: fir-opt --add-debug-info --mlir-print-debuginfo %s -o - | FileCheck %s
+
+module attributes {dlti.dl_spec = #dlti.dl_spec<>} {
+  func.func @_QMhelperPmod_sub(%arg0: !fir.ref<i32> {fir.bindc_name = "a"} ) {
+    return
+  } loc(#loc1)
+  func.func private @_QMhelperFmod_subPchild1(%arg0: !fir.ref<i32> {fir.bindc_name = "b"} ) attributes {fir.host_symbol = @_QMhelperPmod_sub, llvm.linkage = #llvm.linkage<internal>} {
+    return
+  } loc(#loc2)
+  func.func @global_sub_(%arg0: !fir.ref<i32> {fir.bindc_name = "n"} ) attributes {fir.internal_name = "_QPglobal_sub"} {
+    return
+  } loc(#loc3)
+  func.func private @_QFglobal_subPchild2(%arg0: !fir.ref<i32> {fir.bindc_name = "c"}) attributes {fir.host_symbol = @global_sub_, llvm.linkage = #llvm.linkage<internal>} {
+    return
+  } loc(#loc4)
+}
+
+#loc1 = loc("test.f90":5:1)
+#loc2 = loc("test.f90":15:1)
+#loc3 = loc("test.f90":25:1)
+#loc4 = loc("test.f90":35:1)
+
+// CHECK-DAG: #[[SP1:.*]] = #llvm.di_subprogram<{{.*}}name = "mod_sub"{{.*}}>
+// CHECK-DAG: #llvm.di_subprogram<{{.*}}scope = #[[SP1]], name = "child1"{{.*}}>
+// CHECK-DAG: #[[SP2:.*]] = #llvm.di_subprogram<{{.*}}linkageName = "global_sub_"{{.*}}>
+// CHECK-DAG: #llvm.di_subprogram<{{.*}}scope = #[[SP2]], name = "child2"{{.*}}>

``````````

</details>


https://github.com/llvm/llvm-project/pull/99531