[Mlir-commits] [llvm] [mlir] [OMPIRBuilder] Move debug records to correct blocks. (PR #157125)
Abid Qadeer
llvmlistbot at llvm.org
Tue Apr 7 05:05:57 PDT 2026
https://github.com/abidh updated https://github.com/llvm/llvm-project/pull/157125
>From a64ec409d4989982b4c2936540fcda689523d0e7 Mon Sep 17 00:00:00 2001
From: Abid Qadeer <haqadeer at amd.com>
Date: Wed, 3 Sep 2025 22:26:06 +0100
Subject: [PATCH 1/3] [OMPIRBuilder] Move debug records to correct blocks.
Consider the following small OpenMP target region:
!$omp target map(tofrom: x)
x = x + 1
!$omp end target
Currently, when compiled with flang, it will generate an outlined
function like below (with irrelevent bits removed).
void @__omp_offloading_10303_14e8afc__QQmain_l13(ptr %0, ptr %1) {
entry:
%2 = alloca ptr, align 8, addrspace(5)
%3 = addrspacecast ptr addrspace(5) %2 to ptr
...
br i1 %exec_user_code, label %user_code.entry, label %worker.exit
user_code.entry:
%5 = load ptr, ptr %3, align 8, !align !19
br label %omp.region.after_alloca
omp.region.after_alloca:
br label %outlined.body
outlined.body:
br label %omp.target
omp.target:
#dbg_declare(ptr addrspace(5) %2, !20, !DIExpression(), !21)
...
br label %omp.region.cont, !dbg !23
omp.region.cont:
call void @__kmpc_target_deinit()
ret void
worker.exit: ; preds = %entry
ret void
}
Due to how various basic blocks are generated, the debug record for
variable x end up in a different block to the location of the variable
(%5 in this case). The backend drops such debug records.
This PR moves such records in the correct block. If the location field
of the debug record is an instruction, it will ensure that debug record
is in same block as the instruction. If the location is an argument, the
debug record will be moved to the entry block.
---
llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp | 43 ++++--
.../Frontend/OpenMPIRBuilderTest.cpp | 122 ++++++++++++++++++
.../LLVMIR/omptarget-debug-record-pos.mlir | 47 +++++++
3 files changed, 203 insertions(+), 9 deletions(-)
create mode 100644 mlir/test/Target/LLVMIR/omptarget-debug-record-pos.mlir
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index ae8f261ff98b2..e8acbd1ce2ef8 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -8350,29 +8350,54 @@ static void FixupDebugInfoForOutlinedFunction(
OldVar->getFlags(), OldVar->getAlignInBits(), OldVar->getAnnotations());
return NewVar;
};
-
- auto UpdateDebugRecord = [&](auto *DR) {
+ auto UpdateDebugRecord = [&](DbgVariableRecord *DR) {
DILocalVariable *OldVar = DR->getVariable();
unsigned ArgNo = 0;
- for (auto Loc : DR->location_ops()) {
- auto Iter = ValueReplacementMap.find(Loc);
- if (Iter != ValueReplacementMap.end()) {
- DR->replaceVariableLocationOp(Loc, std::get<0>(Iter->second));
- ArgNo = std::get<1>(Iter->second) + 1;
- }
+ if (DR->getNumVariableLocationOps() != 1u)
+ return;
+ auto Loc = DR->getVariableLocationOp(0u);
+ auto Iter = ValueReplacementMap.find(Loc);
+ if (Iter != ValueReplacementMap.end()) {
+ DR->replaceVariableLocationOp(Loc, std::get<0>(Iter->second));
+ ArgNo = std::get<1>(Iter->second) + 1;
}
if (ArgNo != 0)
DR->setVariable(GetUpdatedDIVariable(OldVar, ArgNo));
};
+ SmallVector<DbgVariableRecord *, 4> DVRsToDelete;
+ auto MoveDebugRecordToCorrectBlock = [&](DbgVariableRecord *DVR) {
+ if (DVR->getNumVariableLocationOps() != 1u)
+ return;
+ auto Loc = DVR->getVariableLocationOp(0u);
+ BasicBlock *CurBB = DVR->getParent();
+ BasicBlock *RequiredBB = nullptr;
+
+ if (Instruction *LocInst = dyn_cast<Instruction>(Loc))
+ RequiredBB = LocInst->getParent();
+ else if (isa<llvm::Argument>(Loc))
+ RequiredBB = &(DVR->getFunction()->getEntryBlock());
+
+ if (RequiredBB && RequiredBB != CurBB) {
+ assert(!RequiredBB->empty());
+ RequiredBB->insertDbgRecordBefore(DVR->clone(),
+ RequiredBB->back().getIterator());
+ DVRsToDelete.push_back(DVR);
+ }
+ };
+
// The location and scope of variable intrinsics and records still point to
// the parent function of the target region. Update them.
for (Instruction &I : instructions(Func)) {
assert(!isa<llvm::DbgVariableIntrinsic>(&I) &&
"Unexpected debug intrinsic");
- for (DbgVariableRecord &DVR : filterDbgVars(I.getDbgRecordRange()))
+ for (DbgVariableRecord &DVR : filterDbgVars(I.getDbgRecordRange())) {
UpdateDebugRecord(&DVR);
+ MoveDebugRecordToCorrectBlock(&DVR);
+ }
}
+ for (auto *DVR : DVRsToDelete)
+ DVR->getMarker()->MarkedInstr->dropOneDbgRecord(DVR);
// An extra argument is passed to the device. Create the debug data for it.
if (OMPBuilder.Config.isTargetDevice()) {
DICompileUnit *CU = NewSP->getUnit();
diff --git a/llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp b/llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp
index 7d25ac9cadedb..e63e4daa19e8e 100644
--- a/llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp
+++ b/llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp
@@ -7119,6 +7119,128 @@ TEST_F(OpenMPIRBuilderTest, ConstantAllocaRaise) {
EXPECT_TRUE(isa<ReturnInst>(ExitBlock->getFirstNonPHIIt()));
}
+TEST_F(OpenMPIRBuilderTest, DebugRecordLoc) {
+ OpenMPIRBuilder OMPBuilder(*M);
+ OMPBuilder.setConfig(
+ OpenMPIRBuilderConfig(true, false, false, false, false, false, false));
+ OMPBuilder.initialize();
+
+ Function *OutlinedFn = nullptr;
+ F->setName("func");
+ IRBuilder<> Builder(BB);
+ OpenMPIRBuilder::LocationDescription Loc({Builder.saveIP(), DL});
+ Builder.SetCurrentDebugLocation(DL);
+ auto *Alloca = Builder.CreateAlloca(Builder.getInt32Ty());
+
+ llvm::SmallVector<llvm::Value *, 1> CapturedArgs = {
+ Alloca, Constant::getNullValue(PointerType::get(Ctx, 0))};
+
+ auto SimpleArgAccessorCB =
+ [&](llvm::Argument &Arg, llvm::Value *Input, llvm::Value *&RetVal,
+ llvm::OpenMPIRBuilder::InsertPointTy AllocaIP,
+ llvm::OpenMPIRBuilder::InsertPointTy CodeGenIP) {
+ IRBuilderBase::InsertPointGuard guard(Builder);
+ Builder.SetCurrentDebugLocation(llvm::DebugLoc());
+ if (!OMPBuilder.Config.isTargetDevice()) {
+ RetVal = cast<llvm::Value>(&Arg);
+ return CodeGenIP;
+ }
+ Builder.restoreIP(AllocaIP);
+ llvm::Value *Addr = Builder.CreateAlloca(
+ Arg.getType()->isPointerTy()
+ ? Arg.getType()
+ : Type::getInt64Ty(Builder.getContext()),
+ OMPBuilder.M.getDataLayout().getAllocaAddrSpace());
+ llvm::Value *AddrAscast =
+ Builder.CreatePointerBitCastOrAddrSpaceCast(Addr, Input->getType());
+ Builder.CreateStore(&Arg, AddrAscast);
+ Builder.restoreIP(CodeGenIP);
+ RetVal = Builder.CreateLoad(Arg.getType(), AddrAscast);
+ return Builder.saveIP();
+ };
+
+ llvm::OpenMPIRBuilder::MapInfosTy CombinedInfos;
+ auto GenMapInfoCB = [&](llvm::OpenMPIRBuilder::InsertPointTy codeGenIP)
+ -> llvm::OpenMPIRBuilder::MapInfosTy & {
+ CreateDefaultMapInfos(OMPBuilder, CapturedArgs, CombinedInfos);
+ return CombinedInfos;
+ };
+
+ auto CustomMapperCB = [&](unsigned int I) { return nullptr; };
+ auto BodyGenCB = [&](OpenMPIRBuilder::InsertPointTy AllocaIP,
+ OpenMPIRBuilder::InsertPointTy CodeGenIP)
+ -> OpenMPIRBuilder::InsertPointTy {
+ IRBuilderBase::InsertPointGuard guard(Builder);
+ Builder.SetCurrentDebugLocation(llvm::DebugLoc());
+ Builder.restoreIP(CodeGenIP);
+ auto *mainSP = F->getSubprogram();
+ DIBuilder DIB(*M, false, mainSP->getUnit());
+ auto Type = DIB.createSubroutineType(DIB.getOrCreateTypeArray({}));
+ auto SP = DIB.createFunction(
+ mainSP->getScope(), "target", "", mainSP->getFile(), 2, Type, 2,
+ DINode::FlagZero,
+ DISubprogram::SPFlagDefinition | DISubprogram::SPFlagOptimized);
+ OutlinedFn = CodeGenIP.getBlock()->getParent();
+ OutlinedFn->setSubprogram(SP);
+ DebugLoc Loc = DILocation::get(Ctx, 3, 7, SP);
+ DIType *VoidPtrTy =
+ DIB.createQualifiedType(dwarf::DW_TAG_pointer_type, nullptr);
+ // The location of this variable is in the CapturedArgs so it will get the
+ // alloca/load/store chain in the auto SimpleArgAccessorCB and the location
+ // will change to the load instruction.
+ DILocalVariable *Var1 = DIB.createParameterVariable(
+ SP, "test1", /*ArgNo*/ 1, SP->getFile(), /*LineNo=*/1, VoidPtrTy);
+ DIB.insertDeclare(Alloca, Var1, DIB.createExpression(), Loc,
+ Builder.GetInsertPoint());
+ // This variable will point directly to the function argument.
+ DILocalVariable *Var2 = DIB.createParameterVariable(
+ SP, "test2", /*ArgNo*/ 3, SP->getFile(), /*LineNo=*/1, VoidPtrTy);
+ DIB.insertDeclare(OutlinedFn->getArg(2), Var2, DIB.createExpression(), Loc,
+ Builder.GetInsertPoint());
+
+ return Builder.saveIP();
+ };
+
+ IRBuilder<>::InsertPoint EntryIP(&F->getEntryBlock(),
+ F->getEntryBlock().end());
+ TargetRegionEntryInfo EntryInfo("parent", /*DeviceID=*/1, /*FileID=*/2,
+ /*Line=*/3, /*Count=*/0);
+ OpenMPIRBuilder::TargetKernelRuntimeAttrs RuntimeAttrs;
+ OpenMPIRBuilder::TargetKernelDefaultAttrs DefaultAttrs = {
+ /*ExecFlags=*/omp::OMPTgtExecModeFlags::OMP_TGT_EXEC_MODE_GENERIC,
+ /*MaxTeams=*/{-1}, /*MinTeams=*/0, /*MaxThreads=*/{0}, /*MinThreads=*/0};
+ llvm::OpenMPIRBuilder::TargetDataInfo Info(
+ /*RequiresDevicePointerInfo=*/false,
+ /*SeparateBeginEndCalls=*/true);
+
+ ASSERT_EXPECTED_INIT(
+ OpenMPIRBuilder::InsertPointTy, AfterIP,
+ OMPBuilder.createTarget(Loc, /*IsOffloadEntry=*/true, EntryIP, EntryIP,
+ Info, EntryInfo, DefaultAttrs, RuntimeAttrs,
+ /*IfCond=*/nullptr, CapturedArgs, GenMapInfoCB,
+ BodyGenCB, SimpleArgAccessorCB, CustomMapperCB,
+ {}, false));
+ EXPECT_EQ(DL, Builder.getCurrentDebugLocation());
+ Builder.restoreIP(AfterIP);
+
+ Builder.CreateRetVoid();
+ OMPBuilder.finalize();
+
+ // Check outlined function
+ EXPECT_FALSE(verifyModule(*M, &errs()));
+ EXPECT_NE(OutlinedFn, nullptr);
+ for (Instruction &I : instructions(OutlinedFn)) {
+ for (DbgVariableRecord &DVR : filterDbgVars(I.getDbgRecordRange())) {
+ EXPECT_EQ(DVR.getNumVariableLocationOps(), 1u);
+ auto Loc = DVR.getVariableLocationOp(0u);
+ if (Instruction *LocInst = dyn_cast<Instruction>(Loc))
+ EXPECT_EQ(DVR.getParent(), LocInst->getParent());
+ else if (isa<llvm::Argument>(Loc))
+ EXPECT_EQ(DVR.getParent(), &(OutlinedFn->getEntryBlock()));
+ }
+ }
+}
+
TEST_F(OpenMPIRBuilderTest, CreateTask) {
using InsertPointTy = OpenMPIRBuilder::InsertPointTy;
OpenMPIRBuilder OMPBuilder(*M);
diff --git a/mlir/test/Target/LLVMIR/omptarget-debug-record-pos.mlir b/mlir/test/Target/LLVMIR/omptarget-debug-record-pos.mlir
new file mode 100644
index 0000000000000..bd89a5c1cdfeb
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/omptarget-debug-record-pos.mlir
@@ -0,0 +1,47 @@
+// RUN: mlir-translate -mlir-to-llvmir %s
+
+#di_basic_type = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "real",
+ sizeInBits = 32, encoding = DW_ATE_float>
+#file = #llvm.di_file<"test.f90" in "">
+#di_null_type = #llvm.di_null_type
+#cu = #llvm.di_compile_unit<id = distinct[0]<>,
+ sourceLanguage = DW_LANG_Fortran95, file = #file, isOptimized = false,
+ emissionKind = Full>
+#sp_ty = #llvm.di_subroutine_type<callingConvention = DW_CC_program,
+ types = #di_null_type>
+#sp = #llvm.di_subprogram<compileUnit = #cu, name = "main", file=#file,
+ subprogramFlags = "Definition", type = #sp_ty>
+#sp1 = #llvm.di_subprogram<compileUnit = #cu, name = "target", file=#file,
+ subprogramFlags = "Definition", type = #sp_ty>
+#var1 = #llvm.di_local_variable<scope = #sp, name = "x", file = #file, line = 2,
+ type = #di_basic_type>
+#var2 = #llvm.di_local_variable<scope = #sp1, name = "x", file = #file,
+ line = 2, type = #di_basic_type>
+
+module attributes {dlti.dl_spec = #dlti.dl_spec<#dlti.dl_entry<"dlti.alloca_memory_space", 5 : ui32>>, llvm.target_triple = "amdgcn-amd-amdhsa", omp.is_target_device = true} {
+ llvm.func @main() {
+ %0 = llvm.mlir.constant(1 : i64) : i64 loc(#loc2)
+ %1 = llvm.alloca %0 x i1 : (i64) -> !llvm.ptr<5> loc(#loc2)
+ %2 = llvm.addrspacecast %1 : !llvm.ptr<5> to !llvm.ptr loc(#loc2)
+ llvm.intr.dbg.declare #var1 = %2 : !llvm.ptr loc(#loc2)
+ %4 = omp.map.info var_ptr(%2 : !llvm.ptr, f32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr {name = "x"} loc(#loc2)
+ omp.target map_entries(%4 -> %arg0 : !llvm.ptr) {
+ %5 = llvm.mlir.constant(1.000000e+00 : f32) : f32 loc(#loc3)
+ llvm.intr.dbg.declare #var2 = %arg0 : !llvm.ptr loc(#loc3)
+ %6 = llvm.load %arg0 : !llvm.ptr -> f32 loc(#loc3)
+ %7 = llvm.fadd %6, %5 {fastmathFlags = #llvm.fastmath<contract>} : f32 loc(#loc3)
+ llvm.store %7, %arg0 : f32, !llvm.ptr loc(#loc3)
+ omp.terminator loc(#loc3)
+ } loc(#loc4)
+ llvm.return loc(#loc2)
+ } loc(#loc5)
+}
+
+#loc2 = loc("test.f90":6:7)
+#loc3 = loc("test.f90":8:7)
+#loc4 = loc(fused<#sp1>[#loc3])
+#loc5 = loc(fused<#sp>[#loc2])
+
+// CHECK-LABEL: user_code.entry
+// CHECK: %[[LOAD:.*]] = load ptr
+// CHECK-NEXT: #dbg_declare(ptr %[[LOAD]]{{.*}})
>From cb87bcc80e71ed6e2297cbc704211a5fc88933d2 Mon Sep 17 00:00:00 2001
From: Abid Qadeer <haqadeer at amd.com>
Date: Wed, 1 Apr 2026 20:23:35 +0100
Subject: [PATCH 2/3] Adjust a few testcases.
The dyn_ptr parameter is now the last one. So adjust the unit test
accordingly. Harden omptarget-debug-var-1.mlir which was expecting that
debug metadata in certain order that made it fragile.
---
llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp | 4 ++--
mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir | 10 +++++-----
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp b/llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp
index e63e4daa19e8e..5709bb50a4a0e 100644
--- a/llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp
+++ b/llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp
@@ -7194,8 +7194,8 @@ TEST_F(OpenMPIRBuilderTest, DebugRecordLoc) {
Builder.GetInsertPoint());
// This variable will point directly to the function argument.
DILocalVariable *Var2 = DIB.createParameterVariable(
- SP, "test2", /*ArgNo*/ 3, SP->getFile(), /*LineNo=*/1, VoidPtrTy);
- DIB.insertDeclare(OutlinedFn->getArg(2), Var2, DIB.createExpression(), Loc,
+ SP, "test2", /*ArgNo*/ 2, SP->getFile(), /*LineNo=*/1, VoidPtrTy);
+ DIB.insertDeclare(OutlinedFn->getArg(1), Var2, DIB.createExpression(), Loc,
Builder.GetInsertPoint());
return Builder.saveIP();
diff --git a/mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir b/mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir
index d29fb96549fe0..28ed8e557480f 100644
--- a/mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir
+++ b/mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir
@@ -56,8 +56,8 @@ module attributes {dlti.dl_spec = #dlti.dl_spec<#dlti.dl_entry<"dlti.alloca_memo
#loc4 = loc(fused<#g_var>[#loc1])
#loc5 = loc(fused<#sp1>[#loc2])
-// CHECK: ![[SP:[0-9]+]] = distinct !DISubprogram(name: "target"{{.*}})
-// CHECK: !DILocalVariable(name: "dyn_ptr", arg: 4, scope: ![[SP]]{{.*}}flags: DIFlagArtificial)
-// CHECK: !DILocalVariable(name: "x", arg: 1, scope: ![[SP]]{{.*}})
-// CHECK: !DILocalVariable(name: "arr", arg: 2, scope: ![[SP]]{{.*}})
-// CHECK: !DILocalVariable(name: "i", arg: 3, scope: ![[SP]]{{.*}})
+// CHECK-DAG: ![[SP:[0-9]+]] = distinct !DISubprogram(name: "target"{{.*}})
+// CHECK-DAG: !DILocalVariable(name: "dyn_ptr", arg: 4, scope: ![[SP]]{{.*}}flags: DIFlagArtificial)
+// CHECK-DAG: !DILocalVariable(name: "x", arg: 1, scope: ![[SP]]{{.*}})
+// CHECK-DAG: !DILocalVariable(name: "arr", arg: 2, scope: ![[SP]]{{.*}})
+// CHECK-DAG: !DILocalVariable(name: "i", arg: 3, scope: ![[SP]]{{.*}})
>From 27504332391e729bb81c3c01668455a06d738fb1 Mon Sep 17 00:00:00 2001
From: Abid Qadeer <haqadeer at amd.com>
Date: Tue, 7 Apr 2026 12:46:03 +0100
Subject: [PATCH 3/3] Handle reivew comments.
---
llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index e8acbd1ce2ef8..d7ff32557cf0d 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -8350,16 +8350,16 @@ static void FixupDebugInfoForOutlinedFunction(
OldVar->getFlags(), OldVar->getAlignInBits(), OldVar->getAnnotations());
return NewVar;
};
- auto UpdateDebugRecord = [&](DbgVariableRecord *DR) {
+
+ auto UpdateDebugRecord = [&](auto *DR) {
DILocalVariable *OldVar = DR->getVariable();
unsigned ArgNo = 0;
- if (DR->getNumVariableLocationOps() != 1u)
- return;
- auto Loc = DR->getVariableLocationOp(0u);
- auto Iter = ValueReplacementMap.find(Loc);
- if (Iter != ValueReplacementMap.end()) {
- DR->replaceVariableLocationOp(Loc, std::get<0>(Iter->second));
- ArgNo = std::get<1>(Iter->second) + 1;
+ for (auto Loc : DR->location_ops()) {
+ auto Iter = ValueReplacementMap.find(Loc);
+ if (Iter != ValueReplacementMap.end()) {
+ DR->replaceVariableLocationOp(Loc, std::get<0>(Iter->second));
+ ArgNo = std::get<1>(Iter->second) + 1;
+ }
}
if (ArgNo != 0)
DR->setVariable(GetUpdatedDIVariable(OldVar, ArgNo));
@@ -8369,14 +8369,14 @@ static void FixupDebugInfoForOutlinedFunction(
auto MoveDebugRecordToCorrectBlock = [&](DbgVariableRecord *DVR) {
if (DVR->getNumVariableLocationOps() != 1u)
return;
- auto Loc = DVR->getVariableLocationOp(0u);
+ Value *Loc = DVR->getVariableLocationOp(0u);
BasicBlock *CurBB = DVR->getParent();
BasicBlock *RequiredBB = nullptr;
if (Instruction *LocInst = dyn_cast<Instruction>(Loc))
RequiredBB = LocInst->getParent();
else if (isa<llvm::Argument>(Loc))
- RequiredBB = &(DVR->getFunction()->getEntryBlock());
+ RequiredBB = &DVR->getFunction()->getEntryBlock();
if (RequiredBB && RequiredBB != CurBB) {
assert(!RequiredBB->empty());
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