From 0d63295dd1d9da3fee9c1bbefee70bf8d76da7c9 Mon Sep 17 00:00:00 2001
From: "nawrin.sultana" <nawrinsu@scnbemuxs809.sc.intel.com>
Date: Thu, 25 Jun 2020 15:01:19 -0700
Subject: [PATCH] [SYCL] Handle zero-sized buffer in device accessor

Currently any attempt to create device accessor from zero-sized buffer
crashes with the message 'OpenCL API failed. OpenCL API returns'. This
patch adds meaningful message and throws a cl::sycl::invalid_object_error
with an error code CL_INVALID_VALUE in an attempt to create a device
accessor with zero-sized buffer.

Signed-off-by: Nawrin Sultana nawrin.sultana@intel.com
---
 sycl/include/CL/sycl/accessor.hpp           | 15 +++++++++++
 sycl/test/basic_tests/accessor/accessor.cpp | 29 +++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/sycl/include/CL/sycl/accessor.hpp b/sycl/include/CL/sycl/accessor.hpp
index 125944e6c10eb..b694dfe525ae9 100644
--- a/sycl/include/CL/sycl/accessor.hpp
+++ b/sycl/include/CL/sycl/accessor.hpp
@@ -889,6 +889,7 @@ class accessor :
             getAdjustedMode(PropertyList),
             detail::getSyclObjImpl(BufferRef).get(), AdjustedDim, sizeof(DataT),
             BufferRef.OffsetInBytes, BufferRef.IsSubBuffer) {
+    checkDeviceAccessorBufferSize(BufferRef.get_count());
     if (!IsPlaceH)
       addHostAccessorAndWait(AccessorBaseHost::impl.get());
 #endif
@@ -912,6 +913,7 @@ class accessor :
             getAdjustedMode(PropertyList),
             detail::getSyclObjImpl(BufferRef).get(), Dimensions, sizeof(DataT),
             BufferRef.OffsetInBytes, BufferRef.IsSubBuffer) {
+    checkDeviceAccessorBufferSize(BufferRef.get_count());
     detail::associateWithHandler(CommandGroupHandler, this, AccessTarget);
   }
 #endif
@@ -935,6 +937,7 @@ class accessor :
             getAdjustedMode(PropertyList),
             detail::getSyclObjImpl(BufferRef).get(), Dimensions, sizeof(DataT),
             BufferRef.OffsetInBytes, BufferRef.IsSubBuffer) {
+    checkDeviceAccessorBufferSize(BufferRef.get_count());
     if (!IsPlaceH)
       addHostAccessorAndWait(AccessorBaseHost::impl.get());
   }
@@ -972,6 +975,7 @@ class accessor :
             getAdjustedMode(PropertyList),
             detail::getSyclObjImpl(BufferRef).get(), Dimensions, sizeof(DataT),
             BufferRef.OffsetInBytes, BufferRef.IsSubBuffer) {
+    checkDeviceAccessorBufferSize(BufferRef.get_count());
     detail::associateWithHandler(CommandGroupHandler, this, AccessTarget);
   }
 #endif
@@ -1058,6 +1062,7 @@ class accessor :
                          detail::getSyclObjImpl(BufferRef).get(), Dimensions,
                          sizeof(DataT), BufferRef.OffsetInBytes,
                          BufferRef.IsSubBuffer) {
+    checkDeviceAccessorBufferSize(BufferRef.get_count());
     if (!IsPlaceH)
       addHostAccessorAndWait(AccessorBaseHost::impl.get());
   }
@@ -1097,6 +1102,7 @@ class accessor :
                          detail::getSyclObjImpl(BufferRef).get(), Dimensions,
                          sizeof(DataT), BufferRef.OffsetInBytes,
                          BufferRef.IsSubBuffer) {
+    checkDeviceAccessorBufferSize(BufferRef.get_count());
     detail::associateWithHandler(CommandGroupHandler, this, AccessTarget);
   }
 #endif
@@ -1219,6 +1225,15 @@ class accessor :
 
   bool operator==(const accessor &Rhs) const { return impl == Rhs.impl; }
   bool operator!=(const accessor &Rhs) const { return !(*this == Rhs); }
+
+private:
+  void checkDeviceAccessorBufferSize(const size_t elemInBuffer) {
+    if (!IsHostBuf && elemInBuffer == 0)
+      throw cl::sycl::invalid_object_error(
+          "SYCL buffer size is zero. To create a device accessor, SYCL "
+          "buffer size must be greater than zero.",
+          PI_INVALID_VALUE);
+  }
 };
 
 #if __cplusplus > 201402L
diff --git a/sycl/test/basic_tests/accessor/accessor.cpp b/sycl/test/basic_tests/accessor/accessor.cpp
index ebb99a0f7abbe..413ed9ddd0c13 100644
--- a/sycl/test/basic_tests/accessor/accessor.cpp
+++ b/sycl/test/basic_tests/accessor/accessor.cpp
@@ -540,4 +540,33 @@ int main() {
       return 1;
     }
   }
+
+  // Accessor with buffer size 0.
+  {
+    try {
+      int data[10] = {0};
+      {
+        sycl::buffer<int, 1> b{&data[0], 10};
+        sycl::buffer<int, 1> b1{0};
+
+        sycl::queue queue;
+        queue.submit([&](sycl::handler &cgh) {
+          sycl::accessor<int, 1, sycl::access::mode::read_write,
+                         sycl::access::target::global_buffer>
+              B(b, cgh);
+          auto B1 = b1.template get_access<sycl::access::mode::read_write>(cgh);
+
+          cgh.single_task<class acc_with_zero_sized_buffer>([=]() {
+            B[0] = 1;
+          });
+        });
+      }
+      assert(!"invalid device accessor buffer size exception wasn't caught");
+    } catch (const sycl::invalid_object_error &e) {
+      assert(e.get_cl_code() == CL_INVALID_VALUE);
+    } catch (sycl::exception e) {
+      std::cout << "SYCL exception caught: " << e.what();
+      return 1;
+    }
+  }
 }