[SYCL] Add new metadata kernel_arg_exclusive_ptr (#6190)

kernel_arg_exclusive_ptr metadata guarantees that the kernel
pointer argument, or pointers that derive from it, will not be
dereferenced outside current invocation of the kernel.

At the moment, this guarantee is met by the base pointer of an
accessor.

Signed-off-by: Elizabeth Andrews elizabeth.andrews@intel.com

Author: elizabethandrews

clang/lib/CodeGen/CodeGenModule.cpp

@@ -1807,11 +1807,7 @@ void CodeGenModule::GenOpenCLArgMetadata(llvm::Function *Fn,
 
   // MDNode for listing SYCL kernel pointer arguments originating from
   // accessors.
-  SmallVector<llvm::Metadata *, 8> argSYCLKernelRuntimeAligned;
-
-  // MDNode for listing ESIMD kernel pointer arguments originating from
-  // accessors.
-  SmallVector<llvm::Metadata *, 8> argESIMDAccPtrs;
+  SmallVector<llvm::Metadata *, 8> argSYCLAccessorPtrs;
 
   bool isKernelArgAnAccessor = false;
 
@@ -1919,23 +1915,26 @@ void CodeGenModule::GenOpenCLArgMetadata(llvm::Function *Fn,
               : llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(-1)));
 
       // If a kernel pointer argument comes from an accessor, we generate
-      // a new metadata(kernel_arg_runtime_aligned) to the kernel to indicate
-      // that this pointer has runtime allocated alignment. The value of any
-      // "kernel_arg_runtime_aligned" metadata element is 'true' for any kernel
-      // arguments that corresponds to the base pointer of an accessor and
-      // 'false' otherwise.
+      // the following metadata :
+      // 1. kernel_arg_runtime_aligned - To indicate that this pointer has
+      // runtime allocated alignment.
+      // 2. kernel_arg_exclusive_ptr - To indicate that it is illegal to
+      // dereference the pointer from outside current invocation of the
+      // kernel.
+      // In both cases, the value of metadata element is 'true' for any
+      // kernel arguments that corresponds to the base pointer of an accessor
+      // and 'false' otherwise.
+      // Note: Although both metadata apply only to the base pointer of an
+      // accessor currently, it is possible that one or both may be extended
+      // to include other pointers. Therefore, both metadata are required.
       if (parm->hasAttr<SYCLAccessorPtrAttr>()) {
         isKernelArgAnAccessor = true;
-        argSYCLKernelRuntimeAligned.push_back(
+        argSYCLAccessorPtrs.push_back(
             llvm::ConstantAsMetadata::get(CGF->Builder.getTrue()));
       } else {
-        argSYCLKernelRuntimeAligned.push_back(
+        argSYCLAccessorPtrs.push_back(
             llvm::ConstantAsMetadata::get(CGF->Builder.getFalse()));
       }
-
-      if (FD->hasAttr<SYCLSimdAttr>())
-        argESIMDAccPtrs.push_back(llvm::ConstantAsMetadata::get(
-            CGF->Builder.getInt1(parm->hasAttr<SYCLAccessorPtrAttr>())));
     }
 
   bool IsEsimdFunction = FD && FD->hasAttr<SYCLSimdAttr>();
@@ -1945,10 +1944,12 @@ void CodeGenModule::GenOpenCLArgMetadata(llvm::Function *Fn,
                     llvm::MDNode::get(VMContext, argSYCLBufferLocationAttr));
     // Generate this metadata only if atleast one kernel argument is an
     // accessor.
-    if (isKernelArgAnAccessor)
-      Fn->setMetadata(
-          "kernel_arg_runtime_aligned",
-          llvm::MDNode::get(VMContext, argSYCLKernelRuntimeAligned));
+    if (isKernelArgAnAccessor) {
+      Fn->setMetadata("kernel_arg_runtime_aligned",
+                      llvm::MDNode::get(VMContext, argSYCLAccessorPtrs));
+      Fn->setMetadata("kernel_arg_exclusive_ptr",
+                      llvm::MDNode::get(VMContext, argSYCLAccessorPtrs));
+    }
   } else {
     Fn->setMetadata("kernel_arg_addr_space",
                     llvm::MDNode::get(VMContext, addressQuals));
@@ -1960,9 +1961,11 @@ void CodeGenModule::GenOpenCLArgMetadata(llvm::Function *Fn,
                     llvm::MDNode::get(VMContext, argBaseTypeNames));
     Fn->setMetadata("kernel_arg_type_qual",
                     llvm::MDNode::get(VMContext, argTypeQuals));
+    // FIXME: What is the purpose of this metadata for ESIMD? Can we
+    // reuse kernel_arg_exclusive_ptr or kernel_arg_runtime_aligned ?
     if (IsEsimdFunction)
       Fn->setMetadata("kernel_arg_accessor_ptr",
-                      llvm::MDNode::get(VMContext, argESIMDAccPtrs));
+                      llvm::MDNode::get(VMContext, argSYCLAccessorPtrs));
     if (getCodeGenOpts().EmitOpenCLArgMetadata)
       Fn->setMetadata("kernel_arg_name",
                       llvm::MDNode::get(VMContext, argNames));

clang/test/CodeGenSYCL/kernel-arg-accessor-pointer.cpp

@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -fsycl-is-device -internal-isystem %S/Inputs -triple spir64-unknown-unknown -disable-llvm-passes -opaque-pointers -emit-llvm %s -o - | FileCheck %s
 
-// This test checks if the metadata "kernel-arg-runtime-aligned"
-// is generated if the kernel captures an accessor.
+// This test checks if the metadata "kernel-arg-runtime-aligned" and "kernel_arg_exclusive_ptr"
+// are generated if the kernel captures an accessor.
 
 #include "sycl.hpp"
 
@@ -100,37 +100,43 @@ int main() {
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[ACC_RANGE2:%[a-zA-Z0-9_]+6]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[MEM_RANGE2:%[a-zA-Z0-9_]+7]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[OFFSET2:%[a-zA-Z0-9_]+8]])
-// CHECK-SAME: !kernel_arg_runtime_aligned ![[#RTALIGNED1:]]
+// CHECK-SAME: !kernel_arg_runtime_aligned ![[#ACCESSORMD1:]]
+// CHECK-SAME: !kernel_arg_exclusive_ptr ![[#ACCESSORMD1]]
 
 // Check kernel_readOnlyAcc parameters
 // CHECK: define {{.*}}spir_kernel void @{{.*}}kernel_readOnlyAcc
 // CHECK-SAME: ptr addrspace(1) noundef readonly align 4 [[MEM_ARG1:%[a-zA-Z0-9_]+]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[ACC_RANGE1:%[a-zA-Z0-9_]+1]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[MEM_RANGE1:%[a-zA-Z0-9_]+2]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[OFFSET1:%[a-zA-Z0-9_]+3]]
-// CHECK-SAME: !kernel_arg_runtime_aligned ![[#RTALIGNED2:]]
+// CHECK-SAME: !kernel_arg_runtime_aligned ![[#ACCESSORMD2:]]
+// CHECK-SAME: !kernel_arg_exclusive_ptr ![[#ACCESSORMD2]]
 
 // Check kernel_B parameters
 // CHECK: define {{.*}}spir_kernel void @{{.*}}kernel_B
 // CHECK-NOT: kernel_arg_runtime_aligned
+// CHECK-NOT: kernel_arg_exclusive_ptr
 
 // Check kernel_C parameters
 // CHECK: define {{.*}}spir_kernel void @{{.*}}kernel_C
 // CHECK-SAME: i32 noundef [[MEM_ARG1:%[a-zA-Z0-9_]+]]
 // CHECK-NOT: kernel_arg_runtime_aligned
+// CHECK-NOT: kernel_arg_exclusive_ptr
 
 // Check usm_ptr parameters
 // CHECK: define {{.*}}spir_kernel void @{{.*}}usm_ptr
 // CHECK-SAME: ptr addrspace(1) noundef align 4 [[MEM_ARG1:%[a-zA-Z0-9_]+]],
 // CHECK-SAME: ptr addrspace(1) noundef align 4 [[MEM_ARG1:%[a-zA-Z0-9_]+]]
 // CHECK-NOT: kernel_arg_runtime_aligned
+// CHECK-NOT: kernel_arg_exclusive_ptr
 
 // CHECK: define {{.*}}spir_kernel void @{{.*}}localAccessor
 // CHECK-SAME: ptr addrspace(1) noundef align 4 [[MEM_ARG1:%[a-zA-Z0-9_]+]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[ACC_RANGE1:%[a-zA-Z0-9_]+1]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[MEM_RANGE1:%[a-zA-Z0-9_]+2]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[OFFSET1:%[a-zA-Z0-9_]+3]]
-// CHECK-SAME: !kernel_arg_runtime_aligned ![[#RTALIGNED2]]
+// CHECK-SAME: !kernel_arg_runtime_aligned ![[#ACCESSORMD2]]
+// CHECK-SAME: !kernel_arg_exclusive_ptr ![[#ACCESSORMD2]]
 
 // Check kernel_acc_raw_ptr parameters
 // CHECK: define {{.*}}spir_kernel void @{{.*}}kernel_acc_raw_ptr
@@ -139,7 +145,8 @@ int main() {
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[MEM_RANGE1:%[a-zA-Z0-9_]+2]],
 // CHECK-SAME: ptr noundef byval{{.*}}align 4 [[OFFSET1:%[a-zA-Z0-9_]+3]]
 // CHECK-SAME: ptr addrspace(1) noundef align 4 [[MEM_ARG1:%[a-zA-Z0-9_]+]]
-// CHECK-SAME: !kernel_arg_runtime_aligned ![[#RTALIGNED3:]]
+// CHECK-SAME: !kernel_arg_runtime_aligned ![[#ACCESSORMD3:]]
+// CHECK-SAME: !kernel_arg_exclusive_ptr ![[#ACCESSORMD3]]
 
 // Check esimd_kernel_with_acc parameters
 // CHECK: define {{.*}}spir_kernel void @{{.*}}esimd_kernel_with_acc
@@ -148,6 +155,6 @@ int main() {
 // Check kernel-arg-runtime-aligned metadata.
 // The value of any metadata element is 1 for any kernel arguments
 // that corresponds to the base pointer of an accessor and 0 otherwise.
-// CHECK: ![[#RTALIGNED1]] = !{i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1 false, i1 false}
-// CHECK: ![[#RTALIGNED2]] = !{i1 true, i1 false, i1 false, i1 false}
-// CHECK: ![[#RTALIGNED3]] = !{i1 true, i1 false, i1 false, i1 false, i1 false}
+// CHECK: ![[#ACCESSORMD1]] = !{i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1 false, i1 false}
+// CHECK: ![[#ACCESSORMD2]] = !{i1 true, i1 false, i1 false, i1 false}
+// CHECK: ![[#ACCESSORMD3]] = !{i1 true, i1 false, i1 false, i1 false, i1 false}