[SYCL][USM] Initial clang support for USM (#256)

- Add support pointer types in Integration Header
- Put kernel pointer parameters in the global address space
- Fix CheckSYCLType to support proper recursion through pointers

Signed-off-by: James Brodman <james.brodman@intel.com>

Author: jbrodman

clang/include/clang/Sema/Sema.h

@@ -301,7 +301,8 @@ class SYCLIntegrationHeader {
     kind_accessor = kind_first,
     kind_std_layout,
     kind_sampler,
-    kind_last = kind_sampler
+    kind_pointer,
+    kind_last = kind_pointer
   };
 
 public:

clang/lib/Sema/SemaSYCL.cpp

@@ -331,6 +331,11 @@ class MarkDeviceFunction : public RecursiveASTVisitor<MarkDeviceFunction> {
 
 private:
   bool CheckSYCLType(QualType Ty, SourceRange Loc) {
+    llvm::DenseSet<QualType> visited;
+    return CheckSYCLType(Ty, Loc, visited);
+  }
+
+  bool CheckSYCLType(QualType Ty, SourceRange Loc, llvm::DenseSet<QualType> &Visited) {
     if (Ty->isVariableArrayType()) {
       SemaRef.Diag(Loc.getBegin(), diag::err_vla_unsupported);
       return false;
@@ -339,6 +344,11 @@ class MarkDeviceFunction : public RecursiveASTVisitor<MarkDeviceFunction> {
     while (Ty->isAnyPointerType() || Ty->isArrayType())
       Ty = QualType{Ty->getPointeeOrArrayElementType(), 0};
 
+    // Pointers complicate recursion. Add this type to Visited.
+    // If already there, bail out.
+    if (!Visited.insert(Ty).second)
+      return true;
+    
     if (const auto *CRD = Ty->getAsCXXRecordDecl()) {
       if (CRD->isPolymorphic()) {
         SemaRef.Diag(CRD->getLocation(), diag::err_sycl_virtual_types);
@@ -347,25 +357,25 @@ class MarkDeviceFunction : public RecursiveASTVisitor<MarkDeviceFunction> {
       }
 
       for (const auto &Field : CRD->fields()) {
-        if (!CheckSYCLType(Field->getType(), Field->getSourceRange())) {
+        if (!CheckSYCLType(Field->getType(), Field->getSourceRange(), Visited)) {
           SemaRef.Diag(Loc.getBegin(), diag::note_sycl_used_here);
           return false;
         }
       }
     } else if (const auto *RD = Ty->getAsRecordDecl()) {
       for (const auto &Field : RD->fields()) {
-        if (!CheckSYCLType(Field->getType(), Field->getSourceRange())) {
+        if (!CheckSYCLType(Field->getType(), Field->getSourceRange(), Visited)) {
           SemaRef.Diag(Loc.getBegin(), diag::note_sycl_used_here);
           return false;
         }
       }
     } else if (const auto *FPTy = dyn_cast<FunctionProtoType>(Ty)) {
       for (const auto &ParamTy : FPTy->param_types())
-        if (!CheckSYCLType(ParamTy, Loc))
+        if (!CheckSYCLType(ParamTy, Loc, Visited))
           return false;
-      return CheckSYCLType(FPTy->getReturnType(), Loc);
+      return CheckSYCLType(FPTy->getReturnType(), Loc, Visited);
     } else if (const auto *FTy = dyn_cast<FunctionType>(Ty)) {
-      return CheckSYCLType(FTy->getReturnType(), Loc);
+      return CheckSYCLType(FTy->getReturnType(), Loc, Visited);
     }
     return true;
   }
@@ -766,6 +776,16 @@ static void buildArgTys(ASTContext &Context, CXXRecordDecl *KernelObj,
 
       // Create descriptors for each accessor field in the class or struct
       createParamDescForWrappedAccessors(Fld, ArgTy);
+    } else if (ArgTy->isPointerType()) {
+      // Pointer Arguments need to be in the global address space
+      QualType PointeeTy = ArgTy->getPointeeType();
+      Qualifiers Quals = PointeeTy.getQualifiers();
+      Quals.setAddressSpace(LangAS::opencl_global);
+      PointeeTy = Context.getQualifiedType(PointeeTy.getUnqualifiedType(),
+                                           Quals);
+      QualType ModTy = Context.getPointerType(PointeeTy);
+      
+      CreateAndAddPrmDsc(Fld, ModTy);
     } else if (ArgTy->isScalarType()) {
       CreateAndAddPrmDsc(Fld, ArgTy);
     } else {
@@ -853,6 +873,10 @@ static void populateIntHeader(SYCLIntegrationHeader &H, const StringRef Name,
       uint64_t Sz = Ctx.getTypeSizeInChars(SamplerArg->getType()).getQuantity();
       H.addParamDesc(SYCLIntegrationHeader::kind_sampler,
                      static_cast<unsigned>(Sz), static_cast<unsigned>(Offset));
+    } else if (ArgTy->isPointerType()) {
+      uint64_t Sz = Ctx.getTypeSizeInChars(Fld->getType()).getQuantity();
+      H.addParamDesc(SYCLIntegrationHeader::kind_pointer,
+                     static_cast<unsigned>(Sz), static_cast<unsigned>(Offset));
     } else if (ArgTy->isStructureOrClassType() || ArgTy->isScalarType()) {
       // the parameter is an object of standard layout type or scalar;
       // the check for standard layout is done elsewhere
@@ -1017,6 +1041,7 @@ static const char *paramKind2Str(KernelParamKind K) {
     CASE(accessor);
     CASE(std_layout);
     CASE(sampler);
+    CASE(pointer);
   default:
     return "<ERROR>";
   }

clang/test/CodeGenSYCL/usm-int-header.cpp

@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -std=c++11 -I %S/Inputs -fsycl-is-device -ast-dump %s | FileCheck %s
+// RUN: %clang -I %S/Inputs --sycl -Xclang -fsycl-int-header=%t.h %s -c -o kernel.spv
+// RUN: FileCheck -input-file=%t.h %s --check-prefix=INT-HEADER
+
+// INT-HEADER:{ kernel_param_kind_t::kind_pointer, 8, 0 },
+// INT-HEADER:{ kernel_param_kind_t::kind_pointer, 8, 8 },
+
+//==--usm-int-header.cpp - USM kernel param aspace and int header test -----==//
+//
+// 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 <sycl.hpp>
+
+template <typename name, typename Func>
+__attribute__((sycl_kernel)) void kernel(Func kernelFunc) {
+  kernelFunc();
+}
+
+int main() {
+  int* x;
+  float* y;
+  
+  kernel<class usm_test>([=]() {
+      *x = 42;
+      *y = 3.14;
+    });
+}
+
+// CHECK: FunctionDecl {{.*}}usm_test 'void (__global int *, __global float *)'

sycl/include/CL/sycl/detail/kernel_desc.hpp

@@ -33,7 +33,8 @@ class half;
 enum class kernel_param_kind_t {
   kind_accessor,
   kind_std_layout, // standard layout object parameters
-  kind_sampler
+  kind_sampler,
+  kind_pointer
 };
 
 // describes a kernel parameter

sycl/include/CL/sycl/handler.hpp

@@ -239,9 +239,11 @@ class handler {
     const auto kind_std_layout = detail::kernel_param_kind_t::kind_std_layout;
     const auto kind_accessor = detail::kernel_param_kind_t::kind_accessor;
     const auto kind_sampler = detail::kernel_param_kind_t::kind_sampler;
+    const auto kind_pointer = detail::kernel_param_kind_t::kind_pointer;
 
     switch (Kind) {
-    case kind_std_layout: {
+    case kind_std_layout:
+    case kind_pointer: {
       MArgs.emplace_back(Kind, Ptr, Size, Index + IndexShift);
       break;
     }