[Mlir-commits] [flang] [mlir] [mlir][debug] Allow multiple DIGlobalVariableExpression on globals. (PR #111981)

[Tobias Gysi]

================
@@ -1055,44 +1055,50 @@ LogicalResult ModuleTranslation::convertGlobals() {
     globalsMapping.try_emplace(op, var);
 
     // Add debug information if present.
-    if (op.getDbgExpr()) {
-      llvm::DIGlobalVariableExpression *diGlobalExpr =
-          debugTranslation->translateGlobalVariableExpression(op.getDbgExpr());
-      llvm::DIGlobalVariable *diGlobalVar = diGlobalExpr->getVariable();
-      var->addDebugInfo(diGlobalExpr);
-
-      // There is no `globals` field in DICompileUnitAttr which can be directly
-      // assigned to DICompileUnit. We have to build the list by looking at the
-      // dbgExpr of all the GlobalOps. The scope of the variable is used to get
-      // the DICompileUnit in which to add it.
-      // But there are cases where the scope of a global does not
-      // directly point to the DICompileUnit and we have to do a bit more work
-      // to get to it. Some of those cases are:
-      //
-      // 1. For the languages that support modules, the scope hierarchy can be
-      // variable -> DIModule -> DICompileUnit
-      //
-      // 2. For the Fortran common block variable, the scope hierarchy can be
-      // variable -> DICommonBlock -> DISubprogram -> DICompileUnit
-      //
-      // 3. For entities like static local variables in C or variable with
-      // SAVE attribute in Fortran, the scope hierarchy can be
-      // variable -> DISubprogram -> DICompileUnit
-      llvm::DIScope *scope = diGlobalVar->getScope();
-      if (auto *mod = dyn_cast_if_present<llvm::DIModule>(scope))
-        scope = mod->getScope();
-      else if (auto *cb = dyn_cast_if_present<llvm::DICommonBlock>(scope)) {
-        if (auto *sp = dyn_cast_if_present<llvm::DISubprogram>(cb->getScope()))
-          scope = sp->getUnit();
-      } else if (auto *sp = dyn_cast_if_present<llvm::DISubprogram>(scope))
-        scope = sp->getUnit();
-
-      // Get the compile unit (scope) of the the global variable.
-      if (llvm::DICompileUnit *compileUnit =
-              dyn_cast_if_present<llvm::DICompileUnit>(scope)) {
-        // Update the compile unit with this incoming global variable expression
-        // during the finalizing step later.
-        allGVars[compileUnit].push_back(diGlobalExpr);
+    if (op.getDbgExprs()) {
+      for (auto attr : *op.getDbgExprs()) {
+        if (auto exprAttr =
+                dyn_cast_if_present<DIGlobalVariableExpressionAttr>(attr)) {
----------------
gysit wrote:

Can the debug expression array ever have a nullptr entry or contain something else than a `DIGlobalVariableExpressionAttr`? I would presume not and a `cast<DIGlobalVariableExpressionAttr>(attr) `makes more range. Maybe you can also use `op.getDbgExprs().getAsRange<DIGlobalVariableExpressionAttr>()`?

https://github.com/llvm/llvm-project/pull/111981