[flang][cuda] Add entry point for alloc/free and simple copy

[clementval]

These will be used to translate simple cuf.alloc/cuf.free and cuf.data_transfer on scalar and constant size arrays.

[llvmbot]

@llvm/pr-subscribers-flang-runtime

Author: Valentin Clement (バレンタイン クレメン) (clementval)

Changes

These will be used to translate simple cuf.alloc/cuf.free and cuf.data_transfer on scalar and constant size arrays.

---

Full diff: https://github.com/llvm/llvm-project/pull/109867.diff

4 Files Affected:

• (modified) flang/include/flang/Runtime/CUDA/memory.h (+12)
• (modified) flang/runtime/CUDA/memory.cpp (+29)
• (modified) flang/unittests/Runtime/CUDA/CMakeLists.txt (+1)
• (added) flang/unittests/Runtime/CUDA/Memory.cpp (+30)

diff --git a/flang/include/flang/Runtime/CUDA/memory.h b/flang/include/flang/Runtime/CUDA/memory.h
index 33947248dc4831..2fc28ed1567b89 100644
--- a/flang/include/flang/Runtime/CUDA/memory.h
+++ b/flang/include/flang/Runtime/CUDA/memory.h
@@ -17,12 +17,24 @@ namespace Fortran::runtime::cuda {
 
 extern "C" {
 
+/// Allocate memory on the device.
+void *RTDECL(CUFMemAlloc)(
+    std::size_t bytes, const char *sourceFile = nullptr, int sourceLine = 0);
+
+/// Free memory allocated on the device.
+void RTDECL(CUFMemFree)(
+    void *devicePtr, const char *sourceFile = nullptr, int sourceLine = 0);
+
 /// Set value to the data hold by a descriptor. The \p value pointer must be
 /// addressable to the same amount of bytes specified by the element size of
 /// the descriptor \p desc.
 void RTDECL(CUFMemsetDescriptor)(const Descriptor &desc, void *value,
     const char *sourceFile = nullptr, int sourceLine = 0);
 
+/// Data transfer from a pointer to a pointer.
+void RTDECL(CUFDataTransferPtrPtr)(void *dst, void *src, std::size_t bytes,
+    unsigned mode, const char *sourceFile = nullptr, int sourceLine = 0);
+
 /// Data transfer from a pointer to a descriptor.
 void RTDECL(CUFDataTransferDescPtr)(const Descriptor &dst, void *src,
     std::size_t bytes, unsigned mode, const char *sourceFile = nullptr,
diff --git a/flang/runtime/CUDA/memory.cpp b/flang/runtime/CUDA/memory.cpp
index a287fa14a48789..171203a93be2a9 100644
--- a/flang/runtime/CUDA/memory.cpp
+++ b/flang/runtime/CUDA/memory.cpp
@@ -8,12 +8,25 @@
 
 #include "flang/Runtime/CUDA/memory.h"
 #include "../terminator.h"
+#include "flang/Runtime/CUDA/common.h"
 
 #include "cuda_runtime.h"
 
 namespace Fortran::runtime::cuda {
 extern "C" {
 
+void *RTDEF(CUFMemAlloc)(
+    std::size_t bytes, const char *sourceFile, int sourceLine) {
+  void *ptr;
+  if (bytes != 0)
+    CUDA_REPORT_IF_ERROR(cudaMalloc((void **)&ptr, bytes));
+  return ptr;
+}
+
+void RTDEF(CUFMemFree)(void *ptr, const char *sourceFile, int sourceLine) {
+  CUDA_REPORT_IF_ERROR(cudaFree(ptr));
+}
+
 void RTDEF(CUFMemsetDescriptor)(const Descriptor &desc, void *value,
     const char *sourceFile, int sourceLine) {
   Terminator terminator{sourceFile, sourceLine};
@@ -21,6 +34,22 @@ void RTDEF(CUFMemsetDescriptor)(const Descriptor &desc, void *value,
                    "value to a descriptor");
 }
 
+void RTDEF(CUFDataTransferPtrPtr)(void *dst, void *src, std::size_t bytes,
+    unsigned mode, const char *sourceFile, int sourceLine) {
+  cudaMemcpyKind kind;
+  if (mode == kHostToDevice) {
+    kind = cudaMemcpyHostToDevice;
+  } else if (mode == kDeviceToHost) {
+    kind = cudaMemcpyDeviceToHost;
+  } else if (mode == kDeviceToDevice) {
+    kind = cudaMemcpyDeviceToDevice;
+  } else {
+    Terminator terminator{sourceFile, sourceLine};
+    terminator.Crash("host to host copy not supported");
+  }
+  CUDA_REPORT_IF_ERROR(cudaMemcpy(dst, src, bytes, kind));
+}
+
 void RTDEF(CUFDataTransferDescPtr)(const Descriptor &desc, void *addr,
     std::size_t bytes, unsigned mode, const char *sourceFile, int sourceLine) {
   Terminator terminator{sourceFile, sourceLine};
diff --git a/flang/unittests/Runtime/CUDA/CMakeLists.txt b/flang/unittests/Runtime/CUDA/CMakeLists.txt
index 30fb8c220233c0..a7fe604d687bdd 100644
--- a/flang/unittests/Runtime/CUDA/CMakeLists.txt
+++ b/flang/unittests/Runtime/CUDA/CMakeLists.txt
@@ -3,6 +3,7 @@ if (FLANG_CUF_RUNTIME)
 add_flang_unittest(FlangCufRuntimeTests
   Allocatable.cpp
   AllocatorCUF.cpp
+  Memory.cpp
 )
 
 if (BUILD_SHARED_LIBS)
diff --git a/flang/unittests/Runtime/CUDA/Memory.cpp b/flang/unittests/Runtime/CUDA/Memory.cpp
new file mode 100644
index 00000000000000..95ae6c75e3eeeb
--- /dev/null
+++ b/flang/unittests/Runtime/CUDA/Memory.cpp
@@ -0,0 +1,30 @@
+//===-- flang/unittests/Runtime/Memory.cpp -----------------------*- C++-*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "flang/Runtime/CUDA/memory.h"
+#include "gtest/gtest.h"
+#include "../../../runtime/terminator.h"
+#include "flang/Common/Fortran.h"
+#include "flang/Runtime/CUDA/common.h"
+
+#include "cuda_runtime.h"
+
+using namespace Fortran::runtime::cuda;
+
+TEST(MemoryCUFTest, SimpleAllocTramsferFree) {
+  int *dev = (int *)RTNAME(CUFMemAlloc)(sizeof(int), __FILE__, __LINE__);
+  EXPECT_TRUE(dev != 0);
+  int host = 42;
+  RTNAME(CUFDataTransferPtrPtr)((void *)dev, (void *)&host, sizeof(int),
+      kHostToDevice, __FILE__, __LINE__);
+  host = 0;
+  RTNAME(CUFDataTransferPtrPtr)((void *)&host, (void *)dev, sizeof(int),
+      kDeviceToHost, __FILE__, __LINE__);
+  EXPECT_EQ(42, host);
+  RTNAME(CUFMemFree)((void *)dev, __FILE__, __LINE__);
+}

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[vzakhari]

Thanks!

[clementval]

Thanks!

Thanks for the review Slava!