Added mapping for pointers captured in Lambdas in OpenMP target regions

[DavidTruby]

Summary

This adds a zero length array section mapping for each pointer captured by a lambda that is used in a target region, as per section 2.19.7.1 of the OpenMP 5 specification.

[ABataev]

lib/CodeGen/CGOpenMPRuntime.cpp

8114

I think you csn use EmitLValueForFieldInitialization just like gor the references and move the same code out of then-else branches because they use the same code. I mean, initialization of VarLVal variable can be moved out of the if-else.
Thise 2 functions produce the wame result for non-reference fields.

[DavidTruby]

Moved common VarLVal initialisation out of the if/else statement

[ABataev]

LG

[DavidTruby]

I don't have commit access so can't commit this myself, could you do it for me? Thanks

[ABataev]

In D64558#1580361, @DavidTruby wrote:

I don't have commit access so can't commit this myself, could you do it for me? Thanks

Sure, thanks for the patch!

lib/CodeGen/CGOpenMPRuntime.cpp

if (ThisCapture) {
       Pointers.push_back(ThisLValVal.getPointer());
       Sizes.push_back(
           CGF.Builder.CreateIntCast(CGF.getTypeSize(CGF.getContext().VoidPtrTy),
                                     CGF.Int64Ty, /*isSigned=*/true));
       Types.push_back(OMP_MAP_PTR_AND_OBJ | OMP_MAP_LITERAL |
                       OMP_MAP_MEMBER_OF | OMP_MAP_IMPLICIT);
     }
     for (const LambdaCapture &LC : RD->captures()) {
-      if (LC.getCaptureKind() != LCK_ByRef)
+      if (!LC.capturesVariable())
         continue;
       const VarDecl *VD = LC.getCapturedVar();
+      if (LC.getCaptureKind() != LCK_ByRef && !VD->getType()->isPointerType())
+        continue;
       auto It = Captures.find(VD);
       assert(It != Captures.end() && "Found lambda capture without field.");
+      if (LC.getCaptureKind() == LCK_ByRef) {
         LValue VarLVal = CGF.EmitLValueForFieldInitialization(VDLVal, It->second);
         LValue VarLValVal = CGF.EmitLValueForField(VDLVal, It->second);
         LambdaPointers.try_emplace(VarLVal.getPointer(), VDLVal.getPointer());
         BasePointers.push_back(VarLVal.getPointer());
         Pointers.push_back(VarLValVal.getPointer());
         Sizes.push_back(CGF.Builder.CreateIntCast(
             CGF.getTypeSize(
                 VD->getType().getCanonicalType().getNonReferenceType()),
             CGF.Int64Ty, /*isSigned=*/true));
+      } else {
+        LValue VarLVal = CGF.EmitLValueForField(VDLVal, It->second);
+        RValue VarRVal = CGF.EmitLoadOfLValue(VarLVal, RD->getLocation());
+        LambdaPointers.try_emplace(VarLVal.getPointer(), VDLVal.getPointer());
+        BasePointers.push_back(VarLVal.getPointer());
+        Pointers.push_back(VarRVal.getScalarVal());
+        Sizes.push_back(llvm::ConstantInt::get(CGF.Int64Ty, 0));
+      }
       Types.push_back(OMP_MAP_PTR_AND_OBJ | OMP_MAP_LITERAL |
                       OMP_MAP_MEMBER_OF | OMP_MAP_IMPLICIT);
     }
   }
 
   /// Set correct indices for lambdas captures.
   void adjustMemberOfForLambdaCaptures(
       const llvm::DenseMap<llvm::Value *, llvm::Value *> &LambdaPointers,

test/OpenMP/nvptx_lambda_pointer_capturing.cpp

+// Test host codegen only.
+// RUN: %clang_cc1 -verify -fopenmp -x c++ -std=c++11 -triple powerpc64le-unknown-unknown -fopenmp-targets=powerpc64le-ibm-linux-gnu -emit-llvm %s -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-64
+// RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -triple powerpc64le-unknown-unknown -fopenmp-targets=powerpc64le-ibm-linux-gnu -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -triple powerpc64le-unknown-unknown -fopenmp-targets=powerpc64le-ibm-linux-gnu -std=c++11 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-64
+// RUN: %clang_cc1 -verify -fopenmp -x c++ -std=c++11 -triple i386-unknown-unknown -fopenmp-targets=i386-pc-linux-gnu -emit-llvm %s -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-32
+// RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -triple i386-unknown-unknown -fopenmp-targets=i386-pc-linux-gnu -emit-pch -o %t %s
+// RUN: %clang_cc1 -fopenmp -x c++ -std=c++11 -triple i386-unknown-unknown -fopenmp-targets=i386-pc-linux-gnu -std=c++11 -include-pch %t -verify %s -emit-llvm -o - | FileCheck %s --check-prefix CHECK --check-prefix CHECK-32
+
+// expected-no-diagnostics
+#ifndef HEADER
+#define HEADER
+
+// CHECK: [[ANON_T:%.+]] = type { i32*, i32* }
+// CHECK-DAG: [[SIZES_TEMPLATE:@.+]] = private {{.+}} constant [5 x i[[PTRSZ:32|64]]] [i{{32|64}} 4, i{{32|64}} 4, i{{32|64}} {{8|16}}, i{{32|64}} 0, i{{32|64}} 0]
+// CHECK-DAG: [[TYPES_TEMPLATE:@.+]] = private {{.+}} constant [5 x i64] [i64 800, i64 800, i64 673, i64 844424930132752, i64 844424930132752]
+// CHECK-DAG: [[SIZES:@.+]] = private {{.+}} constant [3 x i[[PTRSZ:32|64]]] [i{{32|64}} {{8|16}}, i{{32|64}} 0, i{{32|64}} 0]
+// CHECK-DAG: [[TYPES:@.+]] = private {{.+}} constant [3 x i64] [i64 673, i64 281474976711440, i64 281474976711440]
+
+template <typename F>
+void omp_loop(int start, int end, F body) {
+#pragma omp target teams distribute parallel for
+  for (int i = start; i < end; ++i) {
+    body(i);
+  }
+}
+
+// CHECK: define {{.*}}[[MAIN:@.+]](
+int main()
+{
+  int* p = new int[100];
+  int* q = new int[100];
+  auto body = [=](int i){
+    p[i] = q[i];
+  };
+
+#pragma omp target teams distribute parallel for
+  for (int i = 0; i < 100; ++i) {
+    body(i);
+  }
+
+// CHECK: [[BASE_PTRS:%.+]] = alloca [3 x i8*]{{.+}}
+// CHECK: [[PTRS:%.+]] = alloca [3 x i8*]{{.+}}
+
+// First gep of pointers inside lambdas to store the values across function call need to be ignored
+// CHECK: {{%.+}} = getelementptr inbounds [[ANON_T]], [[ANON_T]]* %{{.+}}, i{{.+}} 0, i{{.+}} 0
+// CHECK: {{%.+}} = getelementptr inbounds [[ANON_T]], [[ANON_T]]* %{{.+}}, i{{.+}} 0, i{{.+}} 1
+
+// access of pointers inside lambdas
+// CHECK: [[BASE_PTR1:%.+]] = getelementptr inbounds [[ANON_T]], [[ANON_T]]* %{{.+}}, i{{.+}} 0, i{{.+}} 0
+// CHECK: [[PTR1:%.+]] = load i32*, i32** [[BASE_PTR1]]
+// CHECK: [[BASE_PTR2:%.+]] = getelementptr inbounds [[ANON_T]], [[ANON_T]]* %{{.+}}, i{{.+}} 0, i{{.+}} 1
+// CHECK: [[PTR2:%.+]] = load i32*, i32** [[BASE_PTR2]]
+
+// storage of pointers in baseptrs and ptrs arrays
+// CHECK: [[LOC_LAMBDA:%.+]] = getelementptr inbounds [3 x i8*], [3 x i8*]* [[BASE_PTRS]], i{{.+}} 0, i{{.+}} 0
+// CHECK: [[CAST_LAMBDA:%.+]] = bitcast i8** [[LOC_LAMBDA]] to [[ANON_T]]**
+// CHECK: store [[ANON_T]]* %{{.+}}, [[ANON_T]]** [[CAST_LAMBDA]]{{.+}}
+// CHECK: [[LOC_LAMBDA:%.+]] = getelementptr inbounds [3 x i8*], [3 x i8*]* [[PTRS]], i{{.+}} 0, i{{.+}} 0
+// CHECK: [[CAST_LAMBDA:%.+]] = bitcast i8** [[LOC_LAMBDA]] to [[ANON_T]]**
+// CHECK: store [[ANON_T]]* %{{.+}}, [[ANON_T]]** [[CAST_LAMBDA]]{{.+}}
+
+// CHECK: [[LOC_PTR1:%.+]] = getelementptr inbounds [3 x i8*], [3 x i8*]* [[BASE_PTRS]], i{{.+}} 0, i{{.+}} 1
+// CHECK: [[CAST_PTR1:%.+]] = bitcast i8** [[LOC_PTR1]] to i32***
+// CHECK: store i32** [[BASE_PTR1]], i32*** [[CAST_PTR1]]{{.+}}
+// CHECK: [[LOC_PTR1:%.+]] = getelementptr inbounds [3 x i8*], [3 x i8*]* [[PTRS]], i{{.+}} 0, i{{.+}} 1
+// CHECK: [[CAST_PTR1:%.+]] = bitcast i8** [[LOC_PTR1]] to i32**
+// CHECK: store i32* [[PTR1]], i32** [[CAST_PTR1]]{{.+}}
+
+
+// CHECK: [[LOC_PTR2:%.+]] = getelementptr inbounds [3 x i8*], [3 x i8*]* [[BASE_PTRS]], i{{.+}} 0, i{{.+}} 2
+// CHECK: [[CAST_PTR2:%.+]] = bitcast i8** [[LOC_PTR2]] to i32***
+// CHECK: store i32** [[BASE_PTR2]], i32*** [[CAST_PTR2]]{{.+}}
+// CHECK: [[LOC_PTR2:%.+]] = getelementptr inbounds [3 x i8*], [3 x i8*]* [[PTRS]], i{{.+}} 0, i{{.+}} 2
+// CHECK: [[CAST_PTR2:%.+]] = bitcast i8** [[LOC_PTR2]] to i32**
+// CHECK: store i32* [[PTR2]], i32** [[CAST_PTR2]]{{.+}}
+
+
+// actual target invocation
+// CHECK: [[BASES_GEP:%.+]] = getelementptr {{.+}} [3 x {{.+}}*], [3 x {{.+}}*]* [[BASE_PTRS]], {{.+}} 0, {{.+}} 0
+// CHECK: [[PTRS_GEP:%.+]] = getelementptr {{.+}} [3 x {{.+}}*], [3 x {{.+}}*]* [[PTRS]], {{.+}} 0, {{.+}} 0
+// CHECK: {{%.+}} = call{{.+}} @__tgt_target_teams({{.+}}, {{.+}}, {{.+}}, i8** [[BASES_GEP]], i8** [[PTRS_GEP]], i[[PTRSZ]]* getelementptr inbounds ([3 x i{{.+}}], [3 x i{{.+}}]* [[SIZES]], i{{.+}} 0, i{{.+}} 0), i64* getelementptr inbounds ([3 x i64], [3 x i64]* [[TYPES]], i{{.+}} 0, i{{.+}} 0), {{.+}}, {{.+}})
+
+
+  omp_loop(0,100,body);
+}
+
+// CHECK: [[BASE_PTRS:%.+]] = alloca [5 x i8*]{{.+}}
+// CHECK: [[PTRS:%.+]] = alloca [5 x i8*]{{.+}}
+
+// access of pointers inside lambdas
+// CHECK: [[BASE_PTR1:%.+]] = getelementptr inbounds [[ANON_T]], [[ANON_T]]* %{{.+}}, i{{.+}} 0, i{{.+}} 0
+// CHECK: [[PTR1:%.+]] = load i32*, i32** [[BASE_PTR1]]
+// CHECK: [[BASE_PTR2:%.+]] = getelementptr inbounds [[ANON_T]], [[ANON_T]]* %{{.+}}, i{{.+}} 0, i{{.+}} 1
+// CHECK: [[PTR2:%.+]] = load i32*, i32** [[BASE_PTR2]]
+
+// storage of pointers in baseptrs and ptrs arrays
+// CHECK: [[LOC_LAMBDA:%.+]] = getelementptr inbounds [5 x i8*], [5 x i8*]* [[BASE_PTRS]], i{{.+}} 0, i{{.+}} 2
+// CHECK: [[CAST_LAMBDA:%.+]] = bitcast i8** [[LOC_LAMBDA]] to [[ANON_T]]**
+// CHECK: store [[ANON_T]]* %{{.+}}, [[ANON_T]]** [[CAST_LAMBDA]]{{.+}}
+// CHECK: [[LOC_LAMBDA:%.+]] = getelementptr inbounds [5 x i8*], [5 x i8*]* [[PTRS]], i{{.+}} 0, i{{.+}} 2
+// CHECK: [[CAST_LAMBDA:%.+]] = bitcast i8** [[LOC_LAMBDA]] to [[ANON_T]]**
+// CHECK: store [[ANON_T]]* %{{.+}}, [[ANON_T]]** [[CAST_LAMBDA]]{{.+}}
+
+// CHECK: [[LOC_PTR1:%.+]] = getelementptr inbounds [5 x i8*], [5 x i8*]* [[BASE_PTRS]], i{{.+}} 0, i{{.+}} 3
+// CHECK: [[CAST_PTR1:%.+]] = bitcast i8** [[LOC_PTR1]] to i32***
+// CHECK: store i32** [[BASE_PTR1]], i32*** [[CAST_PTR1]]{{.+}}
+// CHECK: [[LOC_PTR1:%.+]] = getelementptr inbounds [5 x i8*], [5 x i8*]* [[PTRS]], i{{.+}} 0, i{{.+}} 3
+// CHECK: [[CAST_PTR1:%.+]] = bitcast i8** [[LOC_PTR1]] to i32**
+// CHECK: store i32* [[PTR1]], i32** [[CAST_PTR1]]{{.+}}
+
+
+// CHECK: [[LOC_PTR2:%.+]] = getelementptr inbounds [5 x i8*], [5 x i8*]* [[BASE_PTRS]], i{{.+}} 0, i{{.+}} 4
+// CHECK: [[CAST_PTR2:%.+]] = bitcast i8** [[LOC_PTR2]] to i32***
+// CHECK: store i32** [[BASE_PTR2]], i32*** [[CAST_PTR2]]{{.+}}
+// CHECK: [[LOC_PTR2:%.+]] = getelementptr inbounds [5 x i8*], [5 x i8*]* [[PTRS]], i{{.+}} 0, i{{.+}} 4
+// CHECK: [[CAST_PTR2:%.+]] = bitcast i8** [[LOC_PTR2]] to i32**
+// CHECK: store i32* [[PTR2]], i32** [[CAST_PTR2]]{{.+}}
+
+
+// actual target invocation
+// CHECK: [[BASES_GEP:%.+]] = getelementptr {{.+}} [5 x {{.+}}*], [5 x {{.+}}*]* [[BASE_PTRS]], {{.+}} 0, {{.+}} 0
+// CHECK: [[PTRS_GEP:%.+]] = getelementptr {{.+}} [5 x {{.+}}*], [5 x {{.+}}*]* [[PTRS]], {{.+}} 0, {{.+}} 0
+// CHECK: {{%.+}} = call{{.+}} @__tgt_target_teams({{.+}}, {{.+}}, {{.+}}, i8** [[BASES_GEP]], i8** [[PTRS_GEP]], i[[PTRSZ]]* getelementptr inbounds ([5 x i{{.+}}], [5 x i{{.+}}]* [[SIZES_TEMPLATE]], i{{.+}} 0, i{{.+}} 0), i64* getelementptr inbounds ([5 x i64], [5 x i64]* [[TYPES_TEMPLATE]], i{{.+}} 0, i{{.+}} 0), {{.+}}, {{.+}})
+
+#endif