[SYCL] Don't use std::optional for the sake of gcc 7.5.0 support (intel#12224)

There is a mismatch between gcc 7.5.0 and newer versions of gcc in terms
of std::optional implementation which causes programs to crash if
program is partially compiled on the system with gcc 7.5.0 and partially
compiled on the system with newer gcc.

Co-authored-by: Larsen, Steffen <steffen.larsen@intel.com>

Author: againull

sycl/include/sycl/handler.hpp

@@ -1120,9 +1120,12 @@ class __SYCL_EXPORT handler {
   };
 
   std::optional<std::array<size_t, 3>> getMaxWorkGroups();
+  // We need to use this version to support gcc 7.5.0. Remove when minimal
+  // supported gcc version is bumped.
+  std::tuple<std::array<size_t, 3>, bool> getMaxWorkGroups_v2();
 
   template <int Dims>
-  std::optional<range<Dims>> getRoundedRange(range<Dims> UserRange) {
+  std::tuple<range<Dims>, bool> getRoundedRange(range<Dims> UserRange) {
     range<Dims> RoundedRange = UserRange;
     // Disable the rounding-up optimizations under these conditions:
     // 1. The env var SYCL_DISABLE_PARALLEL_FOR_RANGE_ROUNDING is set.
@@ -1142,7 +1145,7 @@ class __SYCL_EXPORT handler {
 
     // Perform range rounding if rounding-up is enabled.
     if (this->DisableRangeRounding())
-      return {};
+      return {range<Dims>{}, false};
 
     // Range should be a multiple of this for reasonable performance.
     size_t MinFactorX = 16;
@@ -1166,8 +1169,8 @@ class __SYCL_EXPORT handler {
     // kernel in a 32-bit global range.
     auto Dev = detail::getSyclObjImpl(detail::getDeviceFromHandler(*this));
     id<Dims> MaxNWGs = [&] {
-      auto PiResult = getMaxWorkGroups();
-      if (!PiResult.has_value()) {
+      auto [MaxWGs, HasMaxWGs] = getMaxWorkGroups_v2();
+      if (!HasMaxWGs) {
         id<Dims> Default;
         for (int i = 0; i < Dims; ++i)
           Default[i] = (std::numeric_limits<int32_t>::max)();
@@ -1177,7 +1180,7 @@ class __SYCL_EXPORT handler {
       id<Dims> IdResult;
       size_t Limit = (std::numeric_limits<int>::max)();
       for (int i = 0; i < Dims; ++i)
-        IdResult[i] = (std::min)(Limit, (*PiResult)[Dims - i - 1]);
+        IdResult[i] = (std::min)(Limit, MaxWGs[Dims - i - 1]);
       return IdResult;
     }();
     auto M = (std::numeric_limits<uint32_t>::max)();
@@ -1213,8 +1216,8 @@ class __SYCL_EXPORT handler {
         Adjust(i, MaxRange[i]);
 
     if (!DidAdjust)
-      return {};
-    return RoundedRange;
+      return {range<Dims>{}, false};
+    return {RoundedRange, true};
   }
 
   /// Defines and invokes a SYCL kernel function for the specified range.
@@ -1282,7 +1285,8 @@ class __SYCL_EXPORT handler {
 #if !defined(__SYCL_DISABLE_PARALLEL_FOR_RANGE_ROUNDING__) &&                  \
     !defined(DPCPP_HOST_DEVICE_OPENMP) &&                                      \
     !defined(DPCPP_HOST_DEVICE_PERF_NATIVE) && SYCL_LANGUAGE_VERSION >= 202001
-    if (auto RoundedRange = getRoundedRange(UserRange)) {
+    auto [RoundedRange, HasRoundedRange] = getRoundedRange(UserRange);
+    if (HasRoundedRange) {
       using NameWT = typename detail::get_kernel_wrapper_name_t<NameT>::name;
       auto Wrapper =
           getRangeRoundedKernelLambda<NameWT, TransformedArgType, Dims>(
@@ -1300,7 +1304,7 @@ class __SYCL_EXPORT handler {
       // __SYCL_ASSUME_INT can still be violated. So check the bounds
       // of the user range, instead of the rounded range.
       detail::checkValueRange<Dims>(UserRange);
-      MNDRDesc.set(*RoundedRange);
+      MNDRDesc.set(RoundedRange);
       StoreLambda<KName, decltype(Wrapper), Dims, TransformedArgType>(
           std::move(Wrapper));
       setType(detail::CG::Kernel);

sycl/source/handler.cpp

@@ -1457,5 +1457,12 @@ std::optional<std::array<size_t, 3>> handler::getMaxWorkGroups() {
   return {};
 }
 
+std::tuple<std::array<size_t, 3>, bool> handler::getMaxWorkGroups_v2() {
+  auto ImmRess = getMaxWorkGroups();
+  if (ImmRess)
+    return {*ImmRess, true};
+  return {std::array<size_t, 3>{0, 0, 0}, false};
+}
+
 } // namespace _V1
 } // namespace sycl

sycl/test/abi/sycl_symbols_linux.dump

@@ -4114,6 +4114,7 @@ _ZN4sycl3_V17handler17use_kernel_bundleERKNS0_13kernel_bundleILNS0_12bundle_stat
 _ZN4sycl3_V17handler18RangeRoundingTraceEv
 _ZN4sycl3_V17handler18ext_oneapi_barrierERKSt6vectorINS0_5eventESaIS3_EE
 _ZN4sycl3_V17handler18extractArgsAndReqsEv
+_ZN4sycl3_V17handler19getMaxWorkGroups_v2Ev
 _ZN4sycl3_V17handler19supportsUSMMemcpy2DEv
 _ZN4sycl3_V17handler19supportsUSMMemset2DEv
 _ZN4sycl3_V17handler20DisableRangeRoundingEv

sycl/test/abi/sycl_symbols_windows.dump

@@ -1142,6 +1142,7 @@
 ?getInteropContext@SYCLMemObjT@detail@_V1@sycl@@UEBA?AV?$shared_ptr@Vcontext_impl@detail@_V1@sycl@@@std@@XZ
 ?getKernelName@handler@_V1@sycl@@AEAA?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ
 ?getMaxWorkGroups@handler@_V1@sycl@@AEAA?AV?$optional@V?$array@_K$02@std@@@std@@XZ
+?getMaxWorkGroups_v2@handler@_V1@sycl@@AEAA?AV?$tuple@V?$array@_K$02@std@@_N@std@@XZ
 ?getMemoryObject@AccessorBaseHost@detail@_V1@sycl@@QEBAPEAXXZ
 ?getMemoryObject@SampledImageAccessorBaseHost@detail@_V1@sycl@@QEBAPEAXXZ
 ?getMemoryObject@UnsampledImageAccessorBaseHost@detail@_V1@sycl@@QEBAPEAXXZ