[AMDGPU] Emit .actual_access metadata

Summary:
  Emit .actual_access metadata for the deduced argument access qualifier,
and .access for kernel_arg_access_qual.

Reviewers:
 arsenm

Differential Revision:
  https://reviews.llvm.org/D157451

Author: changpeng

llvm/lib/Target/AMDGPU/AMDGPUHSAMetadataStreamer.cpp

@@ -714,16 +714,20 @@ void MetadataStreamerMsgPackV3::emitKernelArg(const Argument &Arg,
   if (Node && ArgNo < Node->getNumOperands())
     BaseTypeName = cast<MDString>(Node->getOperand(ArgNo))->getString();
 
-  StringRef AccQual;
-  if (Arg.getType()->isPointerTy() && Arg.onlyReadsMemory() &&
-      Arg.hasNoAliasAttr()) {
-    AccQual = "read_only";
-  } else {
-    Node = Func->getMetadata("kernel_arg_access_qual");
-    if (Node && ArgNo < Node->getNumOperands())
-      AccQual = cast<MDString>(Node->getOperand(ArgNo))->getString();
+  StringRef ActAccQual;
+  // Do we really need NoAlias check here?
+  if (Arg.getType()->isPointerTy() && Arg.hasNoAliasAttr()) {
+    if (Arg.onlyReadsMemory())
+      ActAccQual = "read_only";
+    else if (Arg.hasAttribute(Attribute::WriteOnly))
+      ActAccQual = "write_only";
   }
 
+  StringRef AccQual;
+  Node = Func->getMetadata("kernel_arg_access_qual");
+  if (Node && ArgNo < Node->getNumOperands())
+    AccQual = cast<MDString>(Node->getOperand(ArgNo))->getString();
+
   StringRef TypeQual;
   Node = Func->getMetadata("kernel_arg_type_qual");
   if (Node && ArgNo < Node->getNumOperands())
@@ -747,14 +751,15 @@ void MetadataStreamerMsgPackV3::emitKernelArg(const Argument &Arg,
 
   emitKernelArg(DL, ArgTy, ArgAlign,
                 getValueKind(ArgTy, TypeQual, BaseTypeName), Offset, Args,
-                PointeeAlign, Name, TypeName, BaseTypeName, AccQual, TypeQual);
+                PointeeAlign, Name, TypeName, BaseTypeName, ActAccQual,
+                AccQual, TypeQual);
 }
 
 void MetadataStreamerMsgPackV3::emitKernelArg(
     const DataLayout &DL, Type *Ty, Align Alignment, StringRef ValueKind,
     unsigned &Offset, msgpack::ArrayDocNode Args, MaybeAlign PointeeAlign,
     StringRef Name, StringRef TypeName, StringRef BaseTypeName,
-    StringRef AccQual, StringRef TypeQual) {
+    StringRef ActAccQual, StringRef AccQual, StringRef TypeQual) {
   auto Arg = Args.getDocument()->getMapNode();
 
   if (!Name.empty())
@@ -780,7 +785,8 @@ void MetadataStreamerMsgPackV3::emitKernelArg(
   if (auto AQ = getAccessQualifier(AccQual))
     Arg[".access"] = Arg.getDocument()->getNode(*AQ, /*Copy=*/true);
 
-  // TODO: Emit Arg[".actual_access"].
+  if (auto AAQ = getAccessQualifier(ActAccQual))
+    Arg[".actual_access"] = Arg.getDocument()->getNode(*AAQ, /*Copy=*/true);
 
   SmallVector<StringRef, 1> SplitTypeQuals;
   TypeQual.split(SplitTypeQuals, " ", -1, false);

llvm/lib/Target/AMDGPU/AMDGPUHSAMetadataStreamer.h

@@ -105,8 +105,8 @@ class MetadataStreamerMsgPackV3 : public MetadataStreamer {
                      msgpack::ArrayDocNode Args,
                      MaybeAlign PointeeAlign = std::nullopt,
                      StringRef Name = "", StringRef TypeName = "",
-                     StringRef BaseTypeName = "", StringRef AccQual = "",
-                     StringRef TypeQual = "");
+                     StringRef BaseTypeName = "", StringRef ActAccQual = "",
+                     StringRef AccQual = "", StringRef TypeQual = "");
 
   void emitHiddenKernelArgs(const MachineFunction &MF, unsigned &Offset,
                             msgpack::ArrayDocNode Args) override;

llvm/test/CodeGen/AMDGPU/hsa-metadata-deduce-ro-arg.ll

@@ -1,7 +1,7 @@
 ; RUN: llc -mtriple=amdgcn-amd-amdhsa -filetype=obj -o - < %s | llvm-readelf --notes - | FileCheck %s
 
 ; CHECK:        - .args:
-; CHECK-NEXT:       - .access:         read_only
+; CHECK-NEXT:       - .actual_access:  read_only
 ; CHECK-NEXT:         .address_space:  global
 ; CHECK-NEXT:         .is_const:       true
 ; CHECK-NEXT:         .is_restrict:    true

llvm/test/CodeGen/AMDGPU/hsa-metadata-deduced-arg-attr.ll

@@ -0,0 +1,30 @@
+; RUN: llc -mtriple=amdgcn-amd-amdhsa -filetype=obj -o - < %s | llvm-readelf --notes - | FileCheck %s
+
+; CHECK: amdhsa.kernels:
+; CHECK-NEXT:  - .args:
+; CHECK-NEXT:      - .actual_access:  read_only
+; CHECK-LABEL:   .name:          test_noalias_ro_arg
+define amdgpu_kernel void @test_noalias_ro_arg(ptr noalias readonly %in) {
+  ret void
+}
+
+; CHECK:       - .args:
+; CHECK-NOT:     read_only
+; CHECK-LABEL:   .name:          test_only_ro_arg
+define amdgpu_kernel void @test_only_ro_arg(ptr readonly %in) {
+  ret void
+}
+
+; CHECK:       - .args:
+; CHECK-NEXT:      - .actual_access:  write_only
+; CHECK-LABEL:   .name:          test_noalias_wo_arg
+define amdgpu_kernel void @test_noalias_wo_arg(ptr noalias writeonly %out) {
+  ret void
+}
+
+; CHECK:       - .args:
+; CHECK-NOT:     write_only
+; CHECK-LABEL:   .name:          test_only_wo_arg
+define amdgpu_kernel void @test_only_wo_arg(ptr writeonly %out) {
+  ret void
+}