[Mlir-commits] [llvm] [mlir] [OMPIRBuilder][debug] Fix debug info for variables in target region. (PR #118314)
Abid Qadeer
llvmlistbot at llvm.org
Mon Dec 2 07:55:51 PST 2024
https://github.com/abidh created https://github.com/llvm/llvm-project/pull/118314
When a new function is created to handle OpenMP target region, the variables used in it are passed as arguments. The scope and the location of these variable contains still point to te parent function of the target region. Such variables will fail in Verifier as the scope of the variables will be different from the containing functions.
Currently, flang is the only user of createOutlinedFunction and it does not generate any debug data for the the variables in the target region to avoid this error. When this PR is in, we should be able to remove this limit in the flang (and anyother client) and have the better debug experience for the target region.
This PR changes the location and scope of the variables in the target region to point to correct entities. It is similar to what fixupDebugInfoPostExtraction does for CodeExtractor. I initially tried to re-use that function but found quickly that it would require quite a bit of re-factoring and additions before it could be used. It was much simpler to make the changes locally.
>From e6f5c7fa0fa8ee330714c89ffac84a4085f2df74 Mon Sep 17 00:00:00 2001
From: Abid Qadeer <haqadeer at amd.com>
Date: Thu, 28 Nov 2024 21:27:14 +0000
Subject: [PATCH] [OMPIRBuilder][debug] Fix debug info for variables in target
region.
When a new function is created to handle OpenMP target region, the
variables used in it are passed as arguments. The scope and the location
of these variable contains still point to te parent function of the
target region. Such variables will fail in Verifier as the scope of the
variables will be different from the containing functions.
Currently, flang is the only user of createOutlinedFunction and it does
not generate any debug data for the the variables in the target region
to avoid this error. When this PR is in, we should be able to remove
this limit in the flang (and anyother client) and have the better
debug experience for the target region.
This PR changes the location and scope of the variables in the target
region to point to correct entities. It is similar to what
fixupDebugInfoPostExtraction does for CodeExtractor. I initially tried
to re-use that function but found quickly that it would require quite
a bit of re-factoring and additions before it could be used. It was
much simpler to make the changes locally.
---
llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp | 66 +++++++++++++++++++
.../Target/LLVMIR/omptarget-debug-var-1.mlir | 63 ++++++++++++++++++
.../Target/LLVMIR/omptarget-debug-var-2.mlir | 62 +++++++++++++++++
3 files changed, 191 insertions(+)
create mode 100644 mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir
create mode 100644 mlir/test/Target/LLVMIR/omptarget-debug-var-2.mlir
diff --git a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
index 1fae138b449ed5..60f63b6c3dda47 100644
--- a/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
+++ b/llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp
@@ -38,6 +38,8 @@
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
@@ -6830,6 +6832,8 @@ static Expected<Function *> createOutlinedFunction(
? make_range(Func->arg_begin() + 1, Func->arg_end())
: Func->args();
+ DenseMap<Value *, std::tuple<Value *, unsigned>> ValueReplacementMap;
+
auto ReplaceValue = [](Value *Input, Value *InputCopy, Function *Func) {
// Things like GEP's can come in the form of Constants. Constants and
// ConstantExpr's do not have access to the knowledge of what they're
@@ -6871,6 +6875,7 @@ static Expected<Function *> createOutlinedFunction(
if (!AfterIP)
return AfterIP.takeError();
Builder.restoreIP(*AfterIP);
+ ValueReplacementMap[Input] = std::make_tuple(InputCopy, Arg.getArgNo());
// In certain cases a Global may be set up for replacement, however, this
// Global may be used in multiple arguments to the kernel, just segmented
@@ -6902,6 +6907,67 @@ static Expected<Function *> createOutlinedFunction(
for (auto Deferred : DeferredReplacement)
ReplaceValue(std::get<0>(Deferred), std::get<1>(Deferred), Func);
+ DenseMap<const MDNode *, MDNode *> Cache;
+ SmallDenseMap<DILocalVariable *, DILocalVariable *> RemappedVariables;
+
+ auto GetUpdatedDIVariable = [&](DILocalVariable *OldVar, unsigned arg) {
+ auto NewSP = Func->getSubprogram();
+ DILocalVariable *&NewVar = RemappedVariables[OldVar];
+ if (!NewVar) {
+ DILocalScope *NewScope = DILocalScope::cloneScopeForSubprogram(
+ *OldVar->getScope(), *NewSP, Builder.getContext(), Cache);
+ NewVar = llvm::DILocalVariable::get(
+ Builder.getContext(), NewScope, OldVar->getName(), OldVar->getFile(),
+ OldVar->getLine(), OldVar->getType(), arg, OldVar->getFlags(),
+ OldVar->getAlignInBits(), OldVar->getAnnotations());
+ }
+ return NewVar;
+ };
+
+ DISubprogram *NewSP = Func->getSubprogram();
+ if (NewSP) {
+ // 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)) {
+ if (auto *DDI = dyn_cast<llvm::DbgVariableIntrinsic>(&I)) {
+ DILocalVariable *OldVar = DDI->getVariable();
+ unsigned ArgNo = OldVar->getArg();
+ for (auto Loc : DDI->location_ops()) {
+ auto Iter = ValueReplacementMap.find(Loc);
+ if (Iter != ValueReplacementMap.end()) {
+ DDI->replaceVariableLocationOp(Loc, std::get<0>(Iter->second));
+ ArgNo = std::get<1>(Iter->second) + 1;
+ }
+ }
+ DDI->setVariable(GetUpdatedDIVariable(OldVar, ArgNo));
+ }
+ for (DbgVariableRecord &DVR : filterDbgVars(I.getDbgRecordRange())) {
+ DILocalVariable *OldVar = DVR.getVariable();
+ unsigned ArgNo = OldVar->getArg();
+ for (auto Loc : DVR.location_ops()) {
+ auto Iter = ValueReplacementMap.find(Loc);
+ if (Iter != ValueReplacementMap.end()) {
+ DVR.replaceVariableLocationOp(Loc, std::get<0>(Iter->second));
+ ArgNo = std::get<1>(Iter->second) + 1;
+ }
+ }
+ DVR.setVariable(GetUpdatedDIVariable(OldVar, ArgNo));
+ }
+ }
+ // An extra argument is passed to the device. Create the debug data for it.
+ if (OMPBuilder.Config.isTargetDevice()) {
+ DICompileUnit *CU = NewSP->getUnit();
+ DIBuilder DB(*M, true, CU);
+ DIType *VoidPtrTy =
+ DB.createQualifiedType(dwarf::DW_TAG_pointer_type, nullptr);
+ DILocalVariable *Var = DB.createParameterVariable(
+ NewSP, "dyn_ptr", /*ArgNo*/ 1, NewSP->getFile(), /*LineNo=*/0,
+ VoidPtrTy, /*AlwaysPreserve=*/false, DINode::DIFlags::FlagArtificial);
+ auto Loc = DILocation::get(Func->getContext(), 0, 0, NewSP, 0);
+ DB.insertDeclare(&(*Func->arg_begin()), Var, DB.createExpression(), Loc,
+ &(*Func->begin()));
+ }
+ }
return Func;
}
diff --git a/mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir b/mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir
new file mode 100644
index 00000000000000..a20ab130049c6d
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/omptarget-debug-var-1.mlir
@@ -0,0 +1,63 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+#int_ty = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "integer",
+ sizeInBits = 32, encoding = DW_ATE_signed>
+#real_ty = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "real",
+ sizeInBits = 32, encoding = DW_ATE_float>
+#file = #llvm.di_file<"target.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>
+#array_ty = #llvm.di_composite_type<tag = DW_TAG_array_type,
+ baseType = #int_ty, elements = #llvm.di_subrange<count = 10 : i64>>
+#sp_ty = #llvm.di_subroutine_type<callingConvention = DW_CC_program,
+ types = #di_null_type>
+#g_var = #llvm.di_global_variable<scope = #cu, name = "arr",
+ linkageName = "_QFEarr", file = #file, line = 4,
+ type = #array_ty, isDefined = true>
+#g_var_expr = #llvm.di_global_variable_expression<var = #g_var>
+#sp = #llvm.di_subprogram<id = distinct[2]<>, compileUnit = #cu, scope = #file,
+ name = "test", file = #file, subprogramFlags = "Definition", type = #sp_ty>
+#var_arr = #llvm.di_local_variable<scope = #sp,
+ name = "arr", file = #file, line = 4, type = #array_ty>
+#var_i = #llvm.di_local_variable<scope = #sp,
+ name = "i", file = #file, line = 13, type = #int_ty>
+#var_x = #llvm.di_local_variable<scope = #sp,
+ name = "x", file = #file, line = 12, type = #real_ty>
+
+module attributes {omp.is_target_device = true} {
+ llvm.func @test() {
+ %0 = llvm.mlir.constant(1 : i64) : i64
+ %1 = llvm.alloca %0 x f32 : (i64) -> !llvm.ptr
+ %4 = llvm.alloca %0 x i32 : (i64) -> !llvm.ptr
+ %6 = llvm.mlir.constant(9 : index) : i64
+ %7 = llvm.mlir.constant(0 : index) : i64
+ %8 = llvm.mlir.constant(1 : index) : i64
+ %10 = llvm.mlir.constant(10 : index) : i64
+ %11 = llvm.mlir.addressof @_QFEarr : !llvm.ptr
+ %14 = omp.map.info var_ptr(%1 : !llvm.ptr, f32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr
+ %15 = omp.map.bounds lower_bound(%7 : i64) upper_bound(%6 : i64) extent(%10 : i64) stride(%8 : i64) start_idx(%8 : i64)
+ %16 = omp.map.info var_ptr(%11 : !llvm.ptr, !llvm.array<10 x i32>) map_clauses(tofrom) capture(ByRef) bounds(%15) -> !llvm.ptr
+ %17 = omp.map.info var_ptr(%4 : !llvm.ptr, i32) map_clauses(implicit, exit_release_or_enter_alloc) capture(ByCopy) -> !llvm.ptr
+ omp.target map_entries(%14 -> %arg0, %16 -> %arg1, %17 -> %arg2 : !llvm.ptr, !llvm.ptr, !llvm.ptr) {
+ llvm.intr.dbg.declare #var_x = %arg0 : !llvm.ptr
+ llvm.intr.dbg.declare #var_arr = %arg1 : !llvm.ptr
+ llvm.intr.dbg.declare #var_i = %arg2 : !llvm.ptr
+ omp.terminator
+ }
+ llvm.return
+ } loc(#loc3)
+ llvm.mlir.global internal @_QFEarr() {addr_space = 0 : i32, dbg_exprs = [#g_var_expr]} : !llvm.array<10 x i32> {
+ } loc(#loc4)
+}
+#loc1 = loc("target.f90":4:7)
+#loc2 = loc("target.f90":11:7)
+#loc3 = loc(fused<#sp>[#loc2])
+#loc4 = loc(fused<#g_var>[#loc1])
+
+// CHECK: ![[SP:[0-9]+]] = distinct !DISubprogram(name: "__omp_offloading{{.*}}test{{.*}})
+// CHECK: !DILocalVariable(name: "dyn_ptr", arg: 1, scope: ![[SP]]{{.*}}flags: DIFlagArtificial)
+// CHECK: !DILocalVariable(name: "x", arg: 2, scope: ![[SP]]{{.*}})
+// CHECK: !DILocalVariable(name: "arr", arg: 3, scope: ![[SP]]{{.*}})
+// CHECK: !DILocalVariable(name: "i", arg: 4, scope: ![[SP]]{{.*}})
diff --git a/mlir/test/Target/LLVMIR/omptarget-debug-var-2.mlir b/mlir/test/Target/LLVMIR/omptarget-debug-var-2.mlir
new file mode 100644
index 00000000000000..22db86fd85e2cc
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/omptarget-debug-var-2.mlir
@@ -0,0 +1,62 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+#int_ty = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "integer",
+ sizeInBits = 32, encoding = DW_ATE_signed>
+#real_ty = #llvm.di_basic_type<tag = DW_TAG_base_type, name = "real",
+ sizeInBits = 32, encoding = DW_ATE_float>
+#file = #llvm.di_file<"target.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>
+#array_ty = #llvm.di_composite_type<tag = DW_TAG_array_type,
+ baseType = #int_ty, elements = #llvm.di_subrange<count = 10 : i64>>
+#sp_ty = #llvm.di_subroutine_type<callingConvention = DW_CC_program,
+ types = #di_null_type>
+#g_var = #llvm.di_global_variable<scope = #cu, name = "arr",
+ linkageName = "_QFEarr", file = #file, line = 4,
+ type = #array_ty, isDefined = true>
+#g_var_expr = #llvm.di_global_variable_expression<var = #g_var>
+#sp = #llvm.di_subprogram<id = distinct[2]<>, compileUnit = #cu, scope = #file,
+ name = "test", file = #file, subprogramFlags = "Definition", type = #sp_ty>
+#var_arr = #llvm.di_local_variable<scope = #sp,
+ name = "arr", file = #file, line = 4, type = #array_ty>
+#var_i = #llvm.di_local_variable<scope = #sp,
+ name = "i", file = #file, line = 13, type = #int_ty>
+#var_x = #llvm.di_local_variable<scope = #sp,
+ name = "x", file = #file, line = 12, type = #real_ty>
+
+module attributes {omp.is_target_device = false} {
+ llvm.func @test() {
+ %0 = llvm.mlir.constant(1 : i64) : i64
+ %1 = llvm.alloca %0 x f32 : (i64) -> !llvm.ptr
+ %4 = llvm.alloca %0 x i32 : (i64) -> !llvm.ptr
+ %6 = llvm.mlir.constant(9 : index) : i64
+ %7 = llvm.mlir.constant(0 : index) : i64
+ %8 = llvm.mlir.constant(1 : index) : i64
+ %10 = llvm.mlir.constant(10 : index) : i64
+ %11 = llvm.mlir.addressof @_QFEarr : !llvm.ptr
+ %14 = omp.map.info var_ptr(%1 : !llvm.ptr, f32) map_clauses(tofrom) capture(ByRef) -> !llvm.ptr
+ %15 = omp.map.bounds lower_bound(%7 : i64) upper_bound(%6 : i64) extent(%10 : i64) stride(%8 : i64) start_idx(%8 : i64)
+ %16 = omp.map.info var_ptr(%11 : !llvm.ptr, !llvm.array<10 x i32>) map_clauses(tofrom) capture(ByRef) bounds(%15) -> !llvm.ptr
+ %17 = omp.map.info var_ptr(%4 : !llvm.ptr, i32) map_clauses(implicit, exit_release_or_enter_alloc) capture(ByCopy) -> !llvm.ptr
+ omp.target map_entries(%14 -> %arg0, %16 -> %arg1, %17 -> %arg2 : !llvm.ptr, !llvm.ptr, !llvm.ptr) {
+ llvm.intr.dbg.declare #var_x = %arg0 : !llvm.ptr
+ llvm.intr.dbg.declare #var_arr = %arg1 : !llvm.ptr
+ llvm.intr.dbg.declare #var_i = %arg2 : !llvm.ptr
+ omp.terminator
+ }
+ llvm.return
+ } loc(#loc3)
+ llvm.mlir.global internal @_QFEarr() {addr_space = 0 : i32, dbg_exprs = [#g_var_expr]} : !llvm.array<10 x i32> {
+ } loc(#loc4)
+}
+#loc1 = loc("target.f90":4:7)
+#loc2 = loc("target.f90":11:7)
+#loc3 = loc(fused<#sp>[#loc2])
+#loc4 = loc(fused<#g_var>[#loc1])
+
+// CHECK: ![[SP:[0-9]+]] = distinct !DISubprogram(name: "__omp_offloading{{.*}}test{{.*}})
+// CHECK: !DILocalVariable(name: "x", arg: 1, scope: ![[SP]]{{.*}})
+// CHECK: !DILocalVariable(name: "arr", arg: 2, scope: ![[SP]]{{.*}})
+// CHECK: !DILocalVariable(name: "i", arg: 3, scope: ![[SP]]{{.*}})
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