Revert "Revert "[libomptarget] Move resource id functions into target specific code, implement for amdgcn""

Summary:
This reverts commit dd8a7fcdd73dd63529b81bf9f72c7529dfe99ec3.

Alexey reports undefined symbols for the new inline functions defined in target_impl.h
This does not reproduce for me for nvptx, or amdgcn, under release or debug builds.

I believe the patch is fine, based on:
 - the semantics of an inline function in C++ (the cuda INLINE functions end
   up as linkonce_odr in IR), which are only legal to drop if they have no uses
 - the code generated from a debug build of clang 9 does not show these undef symbols
 - the tests pass
 - the code is trivial

To progress from here I either need:
 - A tie break - someone to play the role of CI in determining whether the patch works
 - Alexey to provide sufficient information about his build for me to reproduce the failure
 - Alexey to debug why the symbols are disappearing for him and report back

Reviewers: ABataev, jdoerfert, grokos

Subscribers: jvesely, openmp-commits

Tags: #openmp

Differential Revision: https://reviews.llvm.org/D71502

4 files changed, 15 insertions, 13 deletions

diff --git a/openmp/libomptarget/deviceRTLs/amdgcn/src/target_impl.h b/openmp/libomptarget/deviceRTLs/amdgcn/src/target_impl.h
index 62cbfb0f523..5082d469d05 100644
--- a/openmp/libomptarget/deviceRTLs/amdgcn/src/target_impl.h
+++ b/openmp/libomptarget/deviceRTLs/amdgcn/src/target_impl.h
@@ -136,6 +136,14 @@ EXTERN void __kmpc_impl_threadfence(void);
 EXTERN void __kmpc_impl_threadfence_block(void);
 EXTERN void __kmpc_impl_threadfence_system(void);
 
+// Calls to the AMDGCN layer (assuming 1D layout)
+EXTERN uint64_t __ockl_get_local_size(uint32_t);
+EXTERN uint64_t __ockl_get_num_groups(uint32_t);
+INLINE int GetThreadIdInBlock() { return __builtin_amdgcn_workitem_id_x(); }
+INLINE int GetBlockIdInKernel() { return __builtin_amdgcn_workgroup_id_x(); }
+INLINE int GetNumberOfBlocksInKernel() { return __ockl_get_num_groups(0); }
+INLINE int GetNumberOfThreadsInBlock() { return __ockl_get_local_size(0); }
+
 // DEVICE versions of part of libc
 extern "C" {
 DEVICE __attribute__((noreturn)) void
diff --git a/openmp/libomptarget/deviceRTLs/common/src/support.cu b/openmp/libomptarget/deviceRTLs/common/src/support.cu
index 2f992f2778e..ea1fc3841ad 100644
--- a/openmp/libomptarget/deviceRTLs/common/src/support.cu
+++ b/openmp/libomptarget/deviceRTLs/common/src/support.cu
@@ -98,14 +98,6 @@ DEVICE bool checkRuntimeInitialized(kmp_Ident *loc) {
 //
 ////////////////////////////////////////////////////////////////////////////////
 
-DEVICE int GetThreadIdInBlock() { return threadIdx.x; }
-
-DEVICE int GetBlockIdInKernel() { return blockIdx.x; }
-
-DEVICE int GetNumberOfBlocksInKernel() { return gridDim.x; }
-
-DEVICE int GetNumberOfThreadsInBlock() { return blockDim.x; }
-
 DEVICE unsigned GetWarpId() { return GetThreadIdInBlock() / WARPSIZE; }
 
 DEVICE unsigned GetLaneId() { return GetThreadIdInBlock() & (WARPSIZE - 1); }
diff --git a/openmp/libomptarget/deviceRTLs/common/support.h b/openmp/libomptarget/deviceRTLs/common/support.h
index 8cffd91c9f3..400d2649afd 100644
--- a/openmp/libomptarget/deviceRTLs/common/support.h
+++ b/openmp/libomptarget/deviceRTLs/common/support.h
@@ -1,4 +1,4 @@
-//===--------- support.h - NVPTX OpenMP support functions -------- CUDA -*-===//
+//===--------- support.h - OpenMP GPU support functions ---------- CUDA -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -51,10 +51,6 @@ DEVICE bool checkRuntimeInitialized(kmp_Ident *loc);
 ////////////////////////////////////////////////////////////////////////////////
 
 // get low level ids of resources
-DEVICE int GetThreadIdInBlock();
-DEVICE int GetBlockIdInKernel();
-DEVICE int GetNumberOfBlocksInKernel();
-DEVICE int GetNumberOfThreadsInBlock();
 DEVICE unsigned GetWarpId();
 DEVICE unsigned GetLaneId();
 
diff --git a/openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.h b/openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.h
index fe36a46c5cd..161cd6cac11 100644
--- a/openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.h
+++ b/openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.h
@@ -167,4 +167,10 @@ INLINE void __kmpc_impl_threadfence(void) { __threadfence(); }
 INLINE void __kmpc_impl_threadfence_block(void) { __threadfence_block(); }
 INLINE void __kmpc_impl_threadfence_system(void) { __threadfence_system(); }
 
+// Calls to the NVPTX layer (assuming 1D layout)
+INLINE int GetThreadIdInBlock() { return threadIdx.x; }
+INLINE int GetBlockIdInKernel() { return blockIdx.x; }
+INLINE int GetNumberOfBlocksInKernel() { return gridDim.x; }
+INLINE int GetNumberOfThreadsInBlock() { return blockDim.x; }
+
 #endif