[flang-commits] [flang] [flang] Initial debug info support for local variables. (PR #90905)

[Slava Zakharin via flang-commits]

================
@@ -45,13 +46,44 @@ namespace fir {
 namespace {
 
 class AddDebugInfoPass : public fir::impl::AddDebugInfoBase<AddDebugInfoPass> {
+  void handleDeclareOp(fir::cg::XDeclareOp declOp,
+                       mlir::LLVM::DIFileAttr fileAttr,
+                       mlir::LLVM::DIScopeAttr scopeAttr,
+                       fir::DebugTypeGenerator &typeGen, uint32_t &argNo);
+
 public:
   AddDebugInfoPass(fir::AddDebugInfoOptions options) : Base(options) {}
   void runOnOperation() override;
 };
 
+static uint32_t getLineFromLoc(mlir::Location loc) {
+  uint32_t line = 1;
+  if (auto fileLoc = mlir::dyn_cast<mlir::FileLineColLoc>(loc))
+    line = fileLoc.getLine();
+  return line;
+}
+
 } // namespace
 
+void AddDebugInfoPass::handleDeclareOp(fir::cg::XDeclareOp declOp,
+                                       mlir::LLVM::DIFileAttr fileAttr,
+                                       mlir::LLVM::DIScopeAttr scopeAttr,
+                                       fir::DebugTypeGenerator &typeGen,
+                                       uint32_t &argNo) {
+  mlir::MLIRContext *context = &getContext();
+  mlir::OpBuilder builder(context);
+
+  bool isLocal = (declOp.getMemref().getDefiningOp() != nullptr);
----------------
vzakhari wrote:

MLIR inlining is not quite supported in FIR dialect, but you can experiment with some cases (some of them may not work) using `flang-new -O3 -mmlir -inline-all=true`, e.g. for this test:
```
subroutine test(x, y)
  real, target :: x, y
  x = y ! may alias
  call inner(x, y)
contains
  subroutine inner(x, y)
    real :: x, y
    x = y ! may not alias
  end subroutine inner
end subroutine test
```
I get this MLIR:
```
// -----// IR Dump After Inliner (inline) //----- //
module attributes {dlti.dl_spec = #dlti.dl_spec<#dlti.dl_entry<i1, dense<8> : vector<2xi64>>, #dlti.dl_entry<!llvm.ptr, dense<64> : vector<4xi64>>, #dlti.dl_entry<f80, dense<128> : vector<2xi64>>, #dlti.dl_entry<i32, dense<32> : vector<2xi64>>, #dlti.dl_entry<i16, dense<16> : vector<2xi64>>, #dlti.dl_entry<i8, dense<8> : vector<2xi64>>, #dlti.dl_entry<f128, dense<128> : vector<2xi64>>, #dlti.dl_entry<!llvm.ptr<271>, dense<32> : vector<4xi64>>, #dlti.dl_entry<f16, dense<16> : vector<2xi64>>, #dlti.dl_entry<!llvm.ptr<270>, dense<32> : vector<4xi64>>, #dlti.dl_entry<f64, dense<64> : vector<2xi64>>, #dlti.dl_entry<i128, dense<128> : vector<2xi64>>, #dlti.dl_entry<!llvm.ptr<272>, dense<64> : vector<4xi64>>, #dlti.dl_entry<i64, dense<64> : vector<2xi64>>, #dlti.dl_entry<"dlti.stack_alignment", 128 : i64>, #dlti.dl_entry<"dlti.endianness", "little">>, fir.defaultkind = "a1c4d8i4l4r4", fir.kindmap = "", fir.target_cpu = "x86-64", llvm.data_layout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128", llvm.target_triple = "x86_64-unknown-linux-gnu"} {
  func.func @_QPtest(%arg0: !fir.ref<f32> {fir.bindc_name = "x", fir.target}, %arg1: !fir.ref<f32> {fir.bindc_name = "y", fir.target}) {
    %0 = fir.dummy_scope : !fir.dscope
    %1 = fir.declare %arg0 dummy_scope %0 {fortran_attrs = #fir.var_attrs<target>, uniq_name = "_QFtestEx"} : (!fir.ref<f32>, !fir.dscope) -> !fir.ref<f32>
    %2 = fir.declare %arg1 dummy_scope %0 {fortran_attrs = #fir.var_attrs<target>, uniq_name = "_QFtestEy"} : (!fir.ref<f32>, !fir.dscope) -> !fir.ref<f32>
    %3 = fir.load %2 : !fir.ref<f32>
    fir.store %3 to %1 : !fir.ref<f32>
    %4 = fir.dummy_scope : !fir.dscope
    %5 = fir.declare %1 dummy_scope %4 {uniq_name = "_QFtestFinnerEx"} : (!fir.ref<f32>, !fir.dscope) -> !fir.ref<f32>
    %6 = fir.declare %2 dummy_scope %4 {uniq_name = "_QFtestFinnerEy"} : (!fir.ref<f32>, !fir.dscope) -> !fir.ref<f32>
    %7 = fir.load %6 : !fir.ref<f32>
    fir.store %7 to %5 : !fir.ref<f32>
    return
  }
}
```

https://github.com/llvm/llvm-project/pull/90905