[Mlir-commits] [mlir] a791ba5 - Reland "[OMPIRBuilder] Don't use invalid debug loc in task proxy fn." (#218427)

[llvmlistbot at llvm.org]

Author: Abid Qadeer
Date: 2026-08-26T10:51:30+01:00
New Revision: a791ba532b1db1d1c3a1c6daf1c4137b5ab5b99a

URL: https://github.com/llvm/llvm-project/commit/a791ba532b1db1d1c3a1c6daf1c4137b5ab5b99a
DIFF: https://github.com/llvm/llvm-project/commit/a791ba532b1db1d1c3a1c6daf1c4137b5ab5b99a.diff

LOG: Reland "[OMPIRBuilder] Don't use invalid debug loc in task proxy fn." (#218427)

The proxy function built by `emitTargetTaskProxyFunction` inherited
whatever debug location the builder happened to carry, which belongs to
the target region rather than to the proxy. Save and restore the
insertion point around the proxy and clear the debug location while it
is emitted, so its instructions get none.

History of this change:

  Landed in https://github.com/llvm/llvm-project/pull/148284
  Reverted in https://github.com/llvm/llvm-project/pull/148728
Sanitizer issue fixed in
https://github.com/llvm/llvm-project/pull/148887

The revert was needed because the `InsertPointGuard` added here restores
an insertion point that the `PostOutlineCB` callbacks had meanwhile
invalidated: they erase the instruction the insertion point refers to,
so the guard read freed memory in its destructor. #148887 clears the
insertion point before those erases, which removes the dangling
reference this patch would otherwise expose, so the change is safe to
reapply now.

Verified by reverting #148887 on top of this patch and running the
OpenMP translation tests under valgrind: omptarget-depend.mlir and
omptarget-if-nowait.mlir report an invalid read in
InsertPointGuard::~InsertPointGuard() of memory freed by
Instruction::eraseFromParent() in createTask. With #148887 in place, all
185 tests are clean.

The test also needed updating for syntax that changed while this was out
of tree: omp.target now takes a kernel_type clause, and omp.map.info no
longer accepts name in the attribute dictionary.

Co-authored-by: Cursor <cursoragent at cursor.com>

Added: 
    mlir/test/Target/LLVMIR/omptarget-debug-target-task.mlir

Modified: 
    llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index 6f097fa205c34..1b04fc0b1c22a 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -9497,9 +9497,11 @@ static Function *emitTargetTaskProxyFunction(
 
   bool HasShareds = SharedArgsOperandNo > 0;
   bool HasOffloadingArrays = NumOffloadingArrays > 0;
+  IRBuilder<>::InsertPointGuard IPG(Builder);
   BasicBlock *EntryBB =
       BasicBlock::Create(Builder.getContext(), "entry", ProxyFn);
   Builder.SetInsertPoint(EntryBB);
+  Builder.SetCurrentDebugLocation(llvm::DebugLoc());
 
   SmallVector<Value *> KernelLaunchArgs;
   KernelLaunchArgs.reserve(StaleCI->arg_size());

diff  --git a/mlir/test/Target/LLVMIR/omptarget-debug-target-task.mlir b/mlir/test/Target/LLVMIR/omptarget-debug-target-task.mlir
new file mode 100644
index 0000000000000..77adb4a712e1d
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/omptarget-debug-target-task.mlir
@@ -0,0 +1,49 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+module attributes {omp.is_target_device = false} {
+  llvm.func @omp_target_depend_() {
+    %0 = llvm.mlir.constant(39 : index) : i64
+    %1 = llvm.mlir.constant(1 : index) : i64
+    %2 = llvm.mlir.constant(40 : index) : i64
+    %3 = omp.map.bounds lower_bound(%1 : i64) upper_bound(%0 : i64) extent(%2 : i64) stride(%1 : i64) start_idx(%1 : i64)
+    %4 = llvm.mlir.addressof @_QFEa : !llvm.ptr
+    %5 = omp.map.info var_ptr(%4 : !llvm.ptr, !llvm.array<40 x i32>) map_clauses(from) capture(ByRef) bounds(%3) name("a") -> !llvm.ptr
+    omp.target kernel_type(generic) depend(taskdependin -> %4 : !llvm.ptr) map_entries(%5 -> %arg0 : !llvm.ptr) {
+      %6 = llvm.mlir.constant(100 : index) : i32
+      llvm.store %6, %arg0 : i32, !llvm.ptr
+      omp.terminator
+    } loc(#loc13)
+    llvm.return
+  } loc(#loc12)
+
+  llvm.mlir.global internal @_QFEa() {addr_space = 0 : i32} : !llvm.array<40 x i32> {
+    %0 = llvm.mlir.zero : !llvm.array<40 x i32>
+    llvm.return %0 : !llvm.array<40 x i32>
+  }
+}
+
+#loc1 = loc("test.f90":4:18)
+#loc2 = loc("test.f90":8:7)
+
+#di_file = #llvm.di_file<"test.f90" in "">
+#di_null_type = #llvm.di_null_type
+#di_compile_unit = #llvm.di_compile_unit<id = distinct[0]<>,
+ sourceLanguage = DW_LANG_Fortran95, file = #di_file, producer = "flang",
+ isOptimized = false, emissionKind = LineTablesOnly>
+#di_subroutine_type = #llvm.di_subroutine_type<
+  callingConvention = DW_CC_program, types = #di_null_type>
+#di_subprogram = #llvm.di_subprogram<id = distinct[1]<>,
+  compileUnit = #di_compile_unit, scope = #di_file, name = "main",
+  file = #di_file, subprogramFlags = "Definition|MainSubprogram",
+  type = #di_subroutine_type>
+#di_subprogram1 = #llvm.di_subprogram<compileUnit = #di_compile_unit,
+  name = "target", file = #di_file, subprogramFlags = "Definition",
+  type = #di_subroutine_type>
+
+
+#loc12 = loc(fused<#di_subprogram>[#loc1])
+#loc13 = loc(fused<#di_subprogram1>[#loc2])
+
+// CHECK: define internal void @.omp_target_task_proxy_func
+// CHECK-NOT: !dbg
+// CHECK: }