[flang-commits] [flang] [flang][debug] Generate DISubprogramAttr for omp::TargetOp. (PR #138039)
Abid Qadeer via flang-commits
flang-commits at lists.llvm.org
Wed Apr 30 14:57:14 PDT 2025
https://github.com/abidh created https://github.com/llvm/llvm-project/pull/138039
There are `DeclareOp` present for the variables mapped into target region. That allow us to generate debug information for them. Bu the `TargetOp` is still part of parent function and those variables get the parent function's `DISubprogram` as a scope.
In `OMPIRBuilder`, a new function is created for the `TargetOp`. We also create a new `DISubprogram` for it. All the variables that were in the target region now have to be updated to have the correct scope. This after the fact updating of debug information becomes very difficult in certain cases. Take the example of variable arrays. The type of those arrays depend on the artificial `DILocalVariable`(s) which hold the size(s) of the array. This new function will now require that we generate the new variable and and new types. Similar issue exist for character type variables too.
To avoid this after the fact updating, this PR generates a `DISubprogramAttr` for the `TargetOp` while generating the debug info in flang. This help us avoid updating later.
This PR is flang side of the change. I will open another PR which will make the required changes in `OMPIRBuilder`.
>From e03838394cdbe41959b41977b8b083db5a4c3764 Mon Sep 17 00:00:00 2001
From: Abid Qadeer <haqadeer at amd.com>
Date: Tue, 29 Apr 2025 12:30:42 +0100
Subject: [PATCH] [flang][debug] Generate DISubprogramAttr for omp::TargetOp.
There are DeclareOp present for the variables mapped into target region. That
allow us to generate debug information for them. Bu the TargetOp is still
part of parent function and those variables get the parent function's
DISubprogram as a scope.
In OMPIRBuilder, a new function is created for the TargetOp. We also create a
new DISubprogram for it. All the variables that were in the target region now
have to be updated to have the correct scope. This after the fact updating of
debug information becomes very difficult in certain cases. Take the example of
variable arrays. The type of those arrays depend on the artificial
DILocalVariable(s) which hold the size(s) of the array. This new function will
now require that we generate the new variable and and new types. Similar
issue exist for character type variables too.
To avoid this after the fact updating, this PR generates a DISubprogramAttr
for the TargetOp while generating the debug info in flang. This help us
avoid updating later.
This PR is flang side of the change. I will open another PR which will make
the required changes in OMPIRBuilder.
---
.../lib/Optimizer/Transforms/AddDebugInfo.cpp | 99 ++++++++++++++++++-
.../test/Transforms/debug-omp-target-op-1.fir | 35 +++++++
.../test/Transforms/debug-omp-target-op-2.fir | 53 ++++++++++
3 files changed, 186 insertions(+), 1 deletion(-)
create mode 100644 flang/test/Transforms/debug-omp-target-op-1.fir
create mode 100644 flang/test/Transforms/debug-omp-target-op-2.fir
diff --git a/flang/lib/Optimizer/Transforms/AddDebugInfo.cpp b/flang/lib/Optimizer/Transforms/AddDebugInfo.cpp
index c479c1a0892b5..8e7ae4383bfdc 100644
--- a/flang/lib/Optimizer/Transforms/AddDebugInfo.cpp
+++ b/flang/lib/Optimizer/Transforms/AddDebugInfo.cpp
@@ -34,6 +34,7 @@
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
@@ -103,6 +104,37 @@ bool debugInfoIsAlreadySet(mlir::Location loc) {
return false;
}
+// Generates the name for the artificial DISubprogram that we are going to
+// generate for omp::TargetOp. Its logic is borrowed from
+// getTargetEntryUniqueInfo and
+// TargetRegionEntryInfo::getTargetRegionEntryFnName to generate the same name.
+// But even if there was a slight mismatch, it is not a problem because this
+// name is artifical and not important to debug experience.
+mlir::StringAttr getTargetFunctionName(mlir::MLIRContext *context,
+ mlir::Location Loc,
+ llvm::StringRef parentName) {
+ auto fileLoc = Loc->findInstanceOf<mlir::FileLineColLoc>();
+
+ assert(fileLoc && "No file found from location");
+ llvm::StringRef fileName = fileLoc.getFilename().getValue();
+
+ llvm::sys::fs::UniqueID id;
+ uint64_t line = fileLoc.getLine();
+ size_t fileId;
+ size_t deviceId;
+ if (auto ec = llvm::sys::fs::getUniqueID(fileName, id)) {
+ fileId = llvm::hash_value(fileName.str());
+ deviceId = 0xdeadf17e;
+ } else {
+ fileId = id.getFile();
+ deviceId = id.getDevice();
+ }
+ return mlir::StringAttr::get(
+ context,
+ std::string(llvm::formatv("__omp_offloading_{0:x-}_{1:x-}_{2}_l{3}",
+ deviceId, fileId, parentName, line)));
+}
+
} // namespace
bool AddDebugInfoPass::createCommonBlockGlobal(
@@ -510,8 +542,73 @@ void AddDebugInfoPass::handleFuncOp(mlir::func::FuncOp funcOp,
subTypeAttr, entities, /*annotations=*/{});
funcOp->setLoc(builder.getFusedLoc({l}, spAttr));
+ /* When we process the DeclareOp inside the OpenMP target region, all the
+ variables get the DISubprogram of the parent function of the target op as
+ the scope. In the codegen (to llvm ir), OpenMP target op results in the
+ creation of a separate function. As the variables in the debug info have
+ the DISubprogram of the parent function as the scope, the variables
+ need to be updated at codegen time to avoid verification failures.
+
+ This updating after the fact becomes more and more difficult when types
+ are dependent on local variables like in the case of variable size arrays
+ or string. We not only have to generate new variables but also new types.
+ We can avoid this problem by generating a DISubprogramAttr here for the
+ target op and make sure that all the variables inside the target region
+ get the correct scope in the first place. */
+ funcOp.walk([&](mlir::omp::TargetOp targetOp) {
+ unsigned line = getLineFromLoc(targetOp.getLoc());
+ mlir::StringAttr Name =
+ getTargetFunctionName(context, targetOp.getLoc(), funcOp.getName());
+ mlir::LLVM::DISubprogramFlags flags =
+ mlir::LLVM::DISubprogramFlags::Definition |
+ mlir::LLVM::DISubprogramFlags::LocalToUnit;
+ if (isOptimized)
+ flags = flags | mlir::LLVM::DISubprogramFlags::Optimized;
+
+ mlir::DistinctAttr recId =
+ mlir::DistinctAttr::create(mlir::UnitAttr::get(context));
+ mlir::DistinctAttr Id =
+ mlir::DistinctAttr::create(mlir::UnitAttr::get(context));
+ llvm::SmallVector<mlir::LLVM::DITypeAttr> types;
+ types.push_back(mlir::LLVM::DINullTypeAttr::get(context));
+ mlir::LLVM::DISubroutineTypeAttr spTy =
+ mlir::LLVM::DISubroutineTypeAttr::get(context, CC, types);
+ auto spAttr = mlir::LLVM::DISubprogramAttr::get(
+ context, recId, /*isRecSelf=*/true, Id, compilationUnit, Scope, Name,
+ Name, funcFileAttr, line, line, flags, spTy, /*retainedNodes=*/{},
+ /*annotations=*/{});
+
+ // Make sure that information about the imported modules in copied from the
+ // parent function.
+ llvm::SmallVector<mlir::LLVM::DINodeAttr> OpEntities;
+ for (mlir::LLVM::DINodeAttr N : entities) {
+ if (auto entity = mlir::dyn_cast<mlir::LLVM::DIImportedEntityAttr>(N)) {
+ auto importedEntity = mlir::LLVM::DIImportedEntityAttr::get(
+ context, llvm::dwarf::DW_TAG_imported_module, spAttr,
+ entity.getEntity(), fileAttr, /*line=*/1, /*name=*/nullptr,
+ /*elements*/ {});
+ OpEntities.push_back(importedEntity);
+ }
+ }
+
+ Id = mlir::DistinctAttr::create(mlir::UnitAttr::get(context));
+ spAttr = mlir::LLVM::DISubprogramAttr::get(
+ context, recId, /*isRecSelf=*/false, Id, compilationUnit, Scope, Name,
+ Name, funcFileAttr, line, line, flags, spTy, OpEntities,
+ /*annotations=*/{});
+ targetOp->setLoc(builder.getFusedLoc({targetOp.getLoc()}, spAttr));
+ });
+
funcOp.walk([&](fir::cg::XDeclareOp declOp) {
- handleDeclareOp(declOp, fileAttr, spAttr, typeGen, symbolTable);
+ mlir::LLVM::DISubprogramAttr spTy = spAttr;
+ if (auto tOp = declOp->getParentOfType<mlir::omp::TargetOp>()) {
+ if (auto fusedLoc = llvm::dyn_cast<mlir::FusedLoc>(tOp.getLoc())) {
+ if (auto sp = llvm::dyn_cast<mlir::LLVM::DISubprogramAttr>(
+ fusedLoc.getMetadata()))
+ spTy = sp;
+ }
+ }
+ handleDeclareOp(declOp, fileAttr, spTy, typeGen, symbolTable);
});
// commonBlockMap ensures that we don't create multiple DICommonBlockAttr of
// the same name in one function. But it is ok (rather required) to create
diff --git a/flang/test/Transforms/debug-omp-target-op-1.fir b/flang/test/Transforms/debug-omp-target-op-1.fir
new file mode 100644
index 0000000000000..bb586cdf6e9ab
--- /dev/null
+++ b/flang/test/Transforms/debug-omp-target-op-1.fir
@@ -0,0 +1,35 @@
+// RUN: fir-opt --add-debug-info --mlir-print-debuginfo %s | FileCheck %s
+
+module attributes {dlti.dl_spec = #dlti.dl_spec<>} {
+ func.func @_QQmain() attributes {fir.bindc_name = "test"} {
+ %c13_i32 = arith.constant 13 : i32
+ %c12_i32 = arith.constant 12 : i32
+ %c6_i32 = arith.constant 6 : i32
+ %c1_i32 = arith.constant 1 : i32
+ %c5_i32 = arith.constant 5 : i32
+ %0 = fir.alloca i32 {bindc_name = "x", uniq_name = "_QFEx"} loc(#loc1)
+ %1 = fircg.ext_declare %0 {uniq_name = "_QFEx"} : (!fir.ref<i32>) -> !fir.ref<i32> loc(#loc1)
+ %2 = fir.alloca i32 {bindc_name = "y", uniq_name = "_QFEy"} loc(#loc2)
+ %3 = fircg.ext_declare %2 {uniq_name = "_QFEy"} : (!fir.ref<i32>) -> !fir.ref<i32> loc(#loc2)
+ %4 = omp.map.info var_ptr(%1 : !fir.ref<i32>, i32) map_clauses(tofrom) capture(ByRef) -> !fir.ref<i32> {name = "x"}
+ %5 = omp.map.info var_ptr(%3 : !fir.ref<i32>, i32) map_clauses(tofrom) capture(ByRef) -> !fir.ref<i32> {name = "y"}
+ omp.target map_entries(%4 -> %arg0, %5 -> %arg1 : !fir.ref<i32>, !fir.ref<i32>) {
+ %16 = fircg.ext_declare %arg0 {uniq_name = "_QFEx"} : (!fir.ref<i32>) -> !fir.ref<i32> loc(#loc3)
+ %17 = fircg.ext_declare %arg1 {uniq_name = "_QFEy"} : (!fir.ref<i32>) -> !fir.ref<i32> loc(#loc4)
+ omp.terminator
+ } loc(#loc5)
+ return
+ }
+}
+#loc1 = loc("test.f90":1:1)
+#loc2 = loc("test.f90":3:1)
+#loc3 = loc("test.f90":7:1)
+#loc4 = loc("test.f90":8:1)
+#loc5 = loc("test.f90":6:1)
+
+// CHECK: #[[SP:.*]] = #llvm.di_subprogram<{{.*}}name = "test"{{.*}}>
+// CHECK: #[[SP1:.*]] = #llvm.di_subprogram<{{.*}}name = "__omp_offloading_{{.*}}_QQmain_l6"{{.*}}line = 6{{.*}}subprogramFlags = "LocalToUnit|Definition"{{.*}}>
+// CHECK: #llvm.di_local_variable<scope = #[[SP]], name = "x"{{.*}}line = 1, type = #[[TY:.*]]>
+// CHECK: #llvm.di_local_variable<scope = #[[SP]], name = "y"{{.*}}line = 3, type = #[[TY]]>
+// CHECK: #llvm.di_local_variable<scope = #[[SP1]], name = "x"{{.*}}line = 7, type = #[[TY]]>
+// CHECK: #llvm.di_local_variable<scope = #[[SP1]], name = "y"{{.*}}line = 8, type = #[[TY]]>
diff --git a/flang/test/Transforms/debug-omp-target-op-2.fir b/flang/test/Transforms/debug-omp-target-op-2.fir
new file mode 100644
index 0000000000000..15dcf2389b21d
--- /dev/null
+++ b/flang/test/Transforms/debug-omp-target-op-2.fir
@@ -0,0 +1,53 @@
+// RUN: fir-opt --add-debug-info --mlir-print-debuginfo %s | FileCheck %s
+
+module attributes {dlti.dl_spec = #dlti.dl_spec<>} {
+ func.func @fn_(%arg0: !fir.ref<!fir.array<?x?xi32>> {fir.bindc_name = "b"}, %arg1: !fir.ref<i32> {fir.bindc_name = "c"}, %arg2: !fir.ref<i32> {fir.bindc_name = "d"}) {
+ %c1 = arith.constant 1 : index
+ %c0 = arith.constant 0 : index
+ %0 = fir.alloca i32
+ %1 = fir.alloca i32
+ %2 = fir.undefined !fir.dscope
+ %3 = fircg.ext_declare %arg1 dummy_scope %2 {uniq_name = "_QFfnEc"} : (!fir.ref<i32>, !fir.dscope) -> !fir.ref<i32> loc(#loc2)
+ %4 = fircg.ext_declare %arg2 dummy_scope %2 {uniq_name = "_QFfnEd"} : (!fir.ref<i32>, !fir.dscope) -> !fir.ref<i32> loc(#loc3)
+ %5 = fir.load %3 : !fir.ref<i32>
+ %6 = fir.convert %5 : (i32) -> index
+ %9 = fir.load %4 : !fir.ref<i32>
+ %10 = fir.convert %9 : (i32) -> index
+ %15 = fircg.ext_declare %arg0(%6, %10) dummy_scope %2 {uniq_name = "_QFfnEb"} : (!fir.ref<!fir.array<?x?xi32>>, index, index, !fir.dscope) -> !fir.ref<!fir.array<?x?xi32>> loc(#loc4)
+ %16 = fircg.ext_embox %15(%6, %10) : (!fir.ref<!fir.array<?x?xi32>>, index, index) -> !fir.box<!fir.array<?x?xi32>>
+ %17:3 = fir.box_dims %16, %c0 : (!fir.box<!fir.array<?x?xi32>>, index) -> (index, index, index)
+ %18 = arith.subi %17#1, %c1 : index
+ %19 = omp.map.bounds lower_bound(%c0 : index) upper_bound(%18 : index) extent(%17#1 : index) stride(%17#2 : index) start_idx(%c1 : index) {stride_in_bytes = true}
+ %20 = arith.muli %17#2, %17#1 : index
+ %21:3 = fir.box_dims %16, %c1 : (!fir.box<!fir.array<?x?xi32>>, index) -> (index, index, index)
+ %22 = arith.subi %21#1, %c1 : index
+ %23 = omp.map.bounds lower_bound(%c0 : index) upper_bound(%22 : index) extent(%21#1 : index) stride(%20 : index) start_idx(%c1 : index) {stride_in_bytes = true}
+ %24 = omp.map.info var_ptr(%15 : !fir.ref<!fir.array<?x?xi32>>, i32) map_clauses(tofrom) capture(ByRef) bounds(%19, %23) -> !fir.ref<!fir.array<?x?xi32>> {name = "b"}
+ %25 = omp.map.info var_ptr(%1 : !fir.ref<i32>, i32) map_clauses(implicit, exit_release_or_enter_alloc) capture(ByCopy) -> !fir.ref<i32> {name = ""}
+ %26 = omp.map.info var_ptr(%0 : !fir.ref<i32>, i32) map_clauses(implicit, exit_release_or_enter_alloc) capture(ByCopy) -> !fir.ref<i32> {name = ""}
+ omp.target map_entries(%24 -> %arg3, %25 -> %arg4, %26 -> %arg5 : !fir.ref<!fir.array<?x?xi32>>, !fir.ref<i32>, !fir.ref<i32>) {
+ %27 = fir.load %arg5 : !fir.ref<i32>
+ %28 = fir.load %arg4 : !fir.ref<i32>
+ %29 = fir.convert %27 : (i32) -> index
+ %31 = fir.convert %28 : (i32) -> index
+ %37 = fircg.ext_declare %arg3(%29, %31) {uniq_name = "_QFfnEb"} : (!fir.ref<!fir.array<?x?xi32>>, index, index) -> !fir.ref<!fir.array<?x?xi32>> loc(#loc5)
+ omp.terminator
+ } loc(#loc6)
+ return
+ } loc(#loc7)
+}
+#loc1 = loc("test.f90":1:1)
+#loc2 = loc("test.f90":3:1)
+#loc3 = loc("test.f90":7:1)
+#loc4 = loc("test.f90":8:1)
+#loc5 = loc("test.f90":6:1)
+#loc6 = loc("test.f90":16:1)
+#loc7 = loc("test.f90":26:1)
+
+
+// Test that variable size arrays inside target regions get their own
+// compiler generated variables for size.
+
+// CHECK: #[[SP:.*]] = #llvm.di_subprogram<{{.*}}name = "__omp_offloading_{{.*}}_fn__l16"{{.*}}>
+// CHECK: #llvm.di_local_variable<scope = #[[SP]], name = "._QFfnEb1"{{.*}}>
+// CHECK: #llvm.di_local_variable<scope = #[[SP]], name = "._QFfnEb2"{{.*}}>
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