[Mlir-commits] [mlir] [mlir][llvmir] Fix crash when a CallSiteLoc has a UnknownLoc callee (PR #186860)

[Isaac Nudelman]

https://github.com/nuudlman created https://github.com/llvm/llvm-project/pull/186860

Avoids reading a null StringAttr when no file name is present by manufacturing a default instead.

>From 204035d4e358f721c0b83c86d9f8e425f9fa1b2b Mon Sep 17 00:00:00 2001
From: Isaac Nudelman <isaac.nudelman at ericsson.com>
Date: Mon, 16 Mar 2026 19:43:36 +0100
Subject: [PATCH] [mlir][llvmir] Fix crash when a CallSiteLoc has a UnknownLoc
 callee

Change-Id: I65f1007d155cac405938549b804ceddbfdd3c323
---
 .../LLVMIR/Transforms/DIScopeForLLVMFuncOp.cpp   | 13 +++++++++----
 .../Dialect/LLVMIR/add-debuginfo-func-scope.mlir | 16 ++++++++++++++--
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/mlir/lib/Dialect/LLVMIR/Transforms/DIScopeForLLVMFuncOp.cpp b/mlir/lib/Dialect/LLVMIR/Transforms/DIScopeForLLVMFuncOp.cpp
index 36b31ffc3970e..e2285d57821c0 100644
--- a/mlir/lib/Dialect/LLVMIR/Transforms/DIScopeForLLVMFuncOp.cpp
+++ b/mlir/lib/Dialect/LLVMIR/Transforms/DIScopeForLLVMFuncOp.cpp
@@ -93,11 +93,16 @@ static void addScopeToFunction(LLVM::LLVMFuncOp llvmFunc,
 // Get a nested loc for inlined functions.
 static Location getNestedLoc(Operation *op, LLVM::DIScopeAttr scopeAttr,
                              Location calleeLoc) {
-  auto calleeFileName = extractFileLoc(calleeLoc).getFilename();
   auto *context = op->getContext();
-  LLVM::DIFileAttr calleeFileAttr =
-      LLVM::DIFileAttr::get(context, llvm::sys::path::filename(calleeFileName),
-                            llvm::sys::path::parent_path(calleeFileName));
+  LLVM::DIFileAttr calleeFileAttr;
+  if (auto calleeFileLoc = extractFileLoc(calleeLoc)) {
+    auto calleeFileName = calleeFileLoc.getFilename();
+    calleeFileAttr = LLVM::DIFileAttr::get(
+        context, llvm::sys::path::filename(calleeFileName),
+        llvm::sys::path::parent_path(calleeFileName));
+  } else {
+    calleeFileAttr = LLVM::DIFileAttr::get(context, "<unknown>", "");
+  }
   auto lexicalBlockFileAttr = LLVM::DILexicalBlockFileAttr::get(
       context, scopeAttr, calleeFileAttr, /*discriminator=*/0);
   Location loc = calleeLoc;
diff --git a/mlir/test/Dialect/LLVMIR/add-debuginfo-func-scope.mlir b/mlir/test/Dialect/LLVMIR/add-debuginfo-func-scope.mlir
index 895c3fcb7fb23..e75e0392d894f 100644
--- a/mlir/test/Dialect/LLVMIR/add-debuginfo-func-scope.mlir
+++ b/mlir/test/Dialect/LLVMIR/add-debuginfo-func-scope.mlir
@@ -1,5 +1,5 @@
 // RUN: mlir-opt %s --pass-pipeline="builtin.module(ensure-debug-info-scope-on-llvm-func)" --split-input-file --mlir-print-debuginfo | FileCheck %s
-// RUN: mlir-opt %s --pass-pipeline="builtin.module(ensure-debug-info-scope-on-llvm-func{emission-kind=DebugDirectivesOnly})" --split-input-file --mlir-print-debuginfo | FileCheck --check-prefix=CHECK_OTHER_KIND %s 
+// RUN: mlir-opt %s --pass-pipeline="builtin.module(ensure-debug-info-scope-on-llvm-func{emission-kind=DebugDirectivesOnly})" --split-input-file --mlir-print-debuginfo | FileCheck --check-prefix=CHECK_OTHER_KIND %s
 
 // CHECK-LABEL: llvm.func @func_no_debug()
 // CHECK: llvm.return loc(#loc
@@ -54,7 +54,7 @@ module {
 // CHECK: loc(#loc[[FUNCLOC:[0-9]+]])
 // CHECK: loc(#loc[[MODULELOC:[0-9]+]])
 // CHECK-DAG: #[[DI_FILE_MODULE:.+]] = #llvm.di_file<"bar.mlir" in "baz">
-// CHECK-DAG: #[[DI_FILE_FUNC:.+]] = #llvm.di_file<"file.mlir" in ""> 
+// CHECK-DAG: #[[DI_FILE_FUNC:.+]] = #llvm.di_file<"file.mlir" in "">
 // CHECK-DAG: #loc[[FUNCFILELOC:[0-9]+]] = loc("file.mlir":9:8)
 // CHECK-DAG: #di_compile_unit = #llvm.di_compile_unit<id = distinct[{{.*}}]<>, sourceLanguage = DW_LANG_C, file = #[[DI_FILE_MODULE]], producer = "MLIR", isOptimized = true, emissionKind = LineTablesOnly>
 // CHECK-DAG: #di_subprogram = #llvm.di_subprogram<id = distinct[{{.*}}]<>, compileUnit = #di_compile_unit, scope = #[[DI_FILE_FUNC]], name = "propagate_compile_unit", linkageName = "propagate_compile_unit", file = #[[DI_FILE_FUNC]], line = 9, scopeLine = 9, subprogramFlags = "Definition|Optimized", type = #di_subroutine_type>
@@ -172,3 +172,15 @@ func.func @test_func() {
 #loc = loc("a.py":1150:34)
 #loc1 = loc("b.py":321:17)
 #loc2 = loc(callsite(#loc at #loc1))
+
+
+// -----
+
+// Test that a CallSiteLoc with an UnknownLoc callee does not crash.
+llvm.func @callsite_unknown_callee() {
+  llvm.return loc(#loc_cuc2)
+} loc(#loc_cuc0)
+
+#loc_cuc0 = loc("a.py":1:1)
+#loc_cuc1 = loc(unknown)
+#loc_cuc2 = loc(callsite(#loc_cuc1 at #loc_cuc0))