[SYCL][Clang] Add __sycl_detail__::add_ir_annotations_member attribute (#5879)

These changes introduce the new `__sycl_detail__::add_ir_annotations_member`. This attribute is similar in behaviour to `__sycl_detail__::add_ir_attributes_*` attributes but will generate annotation intrinsic calls rather than LLVM IR attributes.

Author: steffenlarsen

clang/include/clang/Basic/Attr.td

@@ -1689,6 +1689,16 @@ def SYCLAddIRAttributesGlobalVariable : InheritableAttr {
   let Documentation = [SYCLAddIRAttributesGlobalVariableDocs];
 }
 
+def SYCLAddIRAnnotationsMember : InheritableAttr {
+  let Spellings = [CXX11<"__sycl_detail__", "add_ir_annotations_member">];
+  let Args = [VariadicExprArgument<"Args">];
+  let LangOpts = [SYCLIsDevice, SilentlyIgnoreSYCLIsHost];
+  let Subjects = SubjectList<[Field], ErrorDiag>;
+  let AcceptsExprPack = 1;
+  let AdditionalMembers = SYCLAddIRAttrCommonMembers.MemberCode;
+  let Documentation = [SYCLAddIRAnnotationsMemberDocs];
+}
+
 def C11NoReturn : InheritableAttr {
   let Spellings = [Keyword<"_Noreturn">];
   let Subjects = SubjectList<[Function], ErrorDiag>;

clang/include/clang/Basic/AttrDocs.td

@@ -3611,6 +3611,83 @@ where the last N*2 are as described above.
   }];
 }
 
+def SYCLAddIRAnnotationsMemberDocs : Documentation {
+  let Category = DocCatVariable;
+  let Heading = "add_ir_annotations_member";
+  let Content = [{
+This attribute can be applied to a non-static field. Access to a field with this
+attribute will generate a call to ``llvm.ptr.annotation`` with the arguments
+paired.
+The attribute must contain N*2 arguments. Each of the first N of these arguments
+must be either string literals or ``constexpr const char *``. The following N
+must be integer, floating point, character, boolean, ``const char *``, or an
+enumeration as either a literal or ``constexpr`` value. The first N arguments
+and the second N arguments are zipped into pairs when creating the call to
+``llvm.ptr.annotation``, i.e. in the constant global variable pointed to by the
+generated annotation intrinsic call, the N+1'th argument of the attribute will
+occur after the first argument of the attribute, the N+2'th argument of the
+attribute will occur after the second argument of the attribute, etc.
+The generated call to ``llvm.ptr.annotation`` will have the following arguments
+in this order:
+  * First argument is a pointer to the field.
+  * A pointer to a string literal in a constant global variable. This will
+    always be "sycl-properties".
+  * A pointer to a string literal in a constant global variable with the name of
+    the source file.
+  * The line number of the field declaration in the source file.
+  * A pointer to a constant global variable containing pointers to string
+    literals in constant global variables. These pointers to string literals
+    occur in pairs. If the second value of a pair was a ``nullptr`` or an empty
+    string then the pointer will be a null-pointer.
+A pair will not be in the call to ``llvm.ptr.annotation`` if the first value of
+the pair is an empty string.
+
+.. code-block:: c++
+
+  struct Foo {
+    int *ptr
+  #ifdef __SYCL_DEVICE_ONLY__
+        [[__sycl_detail__::add_ir_annotations_member(
+            "Attr1", "Attr2", "Attribute value", 3.14)]]
+  #endif
+        ;
+  };
+  // Accessing the 'ptr' field of 'Foo' will result in a call to
+  // 'llvm.ptr.annotation' with the second argument pointing to a constant
+  // global variable containing "sycl-properties" and the fifth argument
+  // pointing to a constant global variable with pointers to string literals
+  // "Attr1", "Attribute value", "Attr2", "3.14" in that order.
+
+Optionally, the first argument of the attribute can be an initializer list
+containing only string literals. This initializer list acts as a filter,
+allowing only pairs with the first value in the initializer list to be
+generated. If this intializer list is present, the attribute must have N*2+1
+arguments, where the last N*2 are as described above.
+
+.. code-block:: c++
+
+  struct Foo {
+    int *ptr
+  #ifdef __SYCL_DEVICE_ONLY__
+        [[__sycl_detail__::add_ir_annotations_member(
+            {"Attr2"}, "Attr1", "Attr2", "Attribute value", 3.14)]]
+  #endif
+        ;
+  };
+  // Accessing the 'ptr' field of 'Foo' will result in a call to
+  // 'llvm.ptr.annotation' with the second argument pointing to a constant
+  // global variable containing "sycl-properties" and the fifth argument
+  // pointing to a constant global variable with pointers to string literals
+  // "Attr2", "3.14" in that order.
+
+.. Note:: This attribute will only generate a call to ``llvm.ptr.annotation`` in
+  SYCL device code.
+
+.. Note:: This attribute is intended as an internal implementation detail and is
+  not intended to be used by external users.
+  }];
+}
+
 def SYCLDeviceIndirectlyCallableDocs : Documentation {
   let Category = DocCatFunction;
   let Heading = "intel::device_indirectly_callable";

clang/include/clang/Sema/Sema.h

@@ -10666,6 +10666,11 @@ class Sema final {
   void AddSYCLAddIRAttributesGlobalVariableAttr(Decl *D,
                                                 const AttributeCommonInfo &CI,
                                                 MutableArrayRef<Expr *> Args);
+  SYCLAddIRAnnotationsMemberAttr *
+  MergeSYCLAddIRAnnotationsMemberAttr(Decl *D,
+                                      const SYCLAddIRAnnotationsMemberAttr &A);
+  void AddSYCLAddIRAnnotationsMemberAttr(Decl *D, const AttributeCommonInfo &CI,
+                                         MutableArrayRef<Expr *> Args);
   void AddReqdWorkGroupSizeAttr(Decl *D, const AttributeCommonInfo &CI,
                                 Expr *XDim, Expr *YDim, Expr *ZDim);
   ReqdWorkGroupSizeAttr *

clang/lib/CodeGen/CGExpr.cpp

@@ -4524,6 +4524,9 @@ LValue CodeGenFunction::EmitLValueForField(LValue base,
 
   // Emit attribute annotation for a field.
   if (getLangOpts().SYCLIsDevice) {
+    if (field->hasAttr<SYCLAddIRAnnotationsMemberAttr>())
+      addr = EmitFieldSYCLAnnotations(field, addr);
+
     SmallString<256> AnnotStr;
     CGM.generateIntelFPGAAnnotation(field, AnnotStr);
     if (!AnnotStr.empty())

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -2720,6 +2720,40 @@ Address CodeGenFunction::EmitFieldAnnotations(const FieldDecl *D,
   return Address(V, Addr.getElementType(), Addr.getAlignment());
 }
 
+llvm::Value *CodeGenFunction::EmitSYCLAnnotationCall(
+    llvm::Function *AnnotationFn, llvm::Value *AnnotatedVal,
+    SourceLocation Location, const SYCLAddIRAnnotationsMemberAttr *Attr) {
+  SmallVector<llvm::Value *, 5> Args = {
+      AnnotatedVal,
+      Builder.CreateBitCast(CGM.EmitAnnotationString("sycl-properties"),
+                            Int8PtrTy),
+      Builder.CreateBitCast(CGM.EmitAnnotationUnit(Location), Int8PtrTy),
+      CGM.EmitAnnotationLineNo(Location), CGM.EmitSYCLAnnotationArgs(Attr)};
+  return Builder.CreateCall(AnnotationFn, Args);
+}
+
+Address CodeGenFunction::EmitFieldSYCLAnnotations(const FieldDecl *D,
+                                                  Address Addr) {
+  const auto *SYCLAnnotAttr = D->getAttr<SYCLAddIRAnnotationsMemberAttr>();
+  assert(SYCLAnnotAttr && "no add_ir_annotations_member attribute");
+  llvm::Value *V = Addr.getPointer();
+  llvm::Type *VTy = V->getType();
+  auto *PTy = dyn_cast<llvm::PointerType>(VTy);
+  unsigned AS = PTy ? PTy->getAddressSpace() : 0;
+  llvm::Type *IntrType = VTy;
+  if (!VTy->getPointerElementType()->isIntegerTy())
+    IntrType = llvm::PointerType::getWithSamePointeeType(CGM.Int8PtrTy, AS);
+  llvm::Function *F =
+      CGM.getIntrinsic(llvm::Intrinsic::ptr_annotation, IntrType);
+
+  if (VTy != IntrType)
+    V = Builder.CreateBitCast(V, IntrType);
+  V = EmitSYCLAnnotationCall(F, V, D->getLocation(), SYCLAnnotAttr);
+  if (VTy != IntrType)
+    V = Builder.CreateBitCast(V, VTy);
+  return Address(V, Addr.getElementType(), Addr.getAlignment());
+}
+
 Address CodeGenFunction::EmitIntelFPGAFieldAnnotations(const FieldDecl *D,
                                                        Address Addr,
                                                        StringRef AnnotStr) {

clang/lib/CodeGen/CodeGenFunction.h

@@ -4508,6 +4508,16 @@ class CodeGenFunction : public CodeGenTypeCache {
   /// annotation result.
   Address EmitFieldAnnotations(const FieldDecl *D, Address V);
 
+  /// Emit a "sycl-properties" annotation call (intrinsic).
+  llvm::Value *
+  EmitSYCLAnnotationCall(llvm::Function *AnnotationFn,
+                         llvm::Value *AnnotatedVal, SourceLocation Location,
+                         const SYCLAddIRAnnotationsMemberAttr *Attr);
+
+  /// Emit sycl field annotations for given field & value. Returns the
+  /// annotation result.
+  Address EmitFieldSYCLAnnotations(const FieldDecl *D, Address V);
+
   /// Emit Intel FPGA field annotations for the given field and value. Returns
   /// the annotation result.
   Address EmitIntelFPGAFieldAnnotations(const FieldDecl *D, Address V,

clang/lib/CodeGen/CodeGenModule.cpp

@@ -2873,6 +2873,55 @@ void CodeGenModule::AddGlobalAnnotations(const ValueDecl *D,
     Annotations.push_back(EmitAnnotateAttr(GV, I, D->getLocation()));
 }
 
+llvm::Constant *CodeGenModule::EmitSYCLAnnotationArgs(
+    const SYCLAddIRAnnotationsMemberAttr *Attr) {
+  llvm::SmallVector<std::pair<std::string, std::string>, 4>
+      AnnotationNameValPairs =
+          Attr->getFilteredAttributeNameValuePairs(getContext());
+  if (AnnotationNameValPairs.empty())
+    return llvm::ConstantPointerNull::get(GlobalsInt8PtrTy);
+
+  // For each name-value pair of the SYCL annotation attribute, create an
+  // annotation string for it. This will be the annotation arguments. If the
+  // value is the empty string, use a null-pointer instead.
+  llvm::SmallVector<llvm::Constant *, 4> LLVMArgs;
+  llvm::FoldingSetNodeID ID;
+  LLVMArgs.reserve(AnnotationNameValPairs.size() * 2);
+  for (const std::pair<std::string, std::string> &NVP :
+       AnnotationNameValPairs) {
+    llvm::Constant *NameStrC = EmitAnnotationString(NVP.first);
+    llvm::Constant *ValueStrC =
+        NVP.second == "" ? llvm::ConstantPointerNull::get(GlobalsInt8PtrTy)
+                         : EmitAnnotationString(NVP.second);
+    LLVMArgs.push_back(NameStrC);
+    LLVMArgs.push_back(ValueStrC);
+    ID.Add(NameStrC);
+    ID.Add(ValueStrC);
+  }
+
+  // If another SYCL annotation had the same arguments we can reuse the
+  // annotation value it created.
+  llvm::Constant *&LookupRef = SYCLAnnotationArgs[ID.ComputeHash()];
+  if (LookupRef)
+    return LookupRef;
+
+  // Create an anonymous struct global variable pointing to the annotation
+  // arguments in the order they were added above. This is the final constant
+  // used as the annotation value.
+  auto *Struct = llvm::ConstantStruct::getAnon(LLVMArgs);
+  auto *GV = new llvm::GlobalVariable(getModule(), Struct->getType(), true,
+                                      llvm::GlobalValue::PrivateLinkage, Struct,
+                                      ".args");
+  GV->setSection(AnnotationSection);
+  GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
+  auto *Bitcasted = llvm::ConstantExpr::getBitCast(GV, GlobalsInt8PtrTy);
+
+  // Set the look-up reference to the final annotation value for future
+  // annotations to reuse.
+  LookupRef = Bitcasted;
+  return Bitcasted;
+}
+
 void CodeGenModule::AddGlobalSYCLIRAttributes(llvm::GlobalVariable *GV,
                                               const RecordDecl *RD) {
   const auto *A = RD->getAttr<SYCLAddIRAttributesGlobalVariableAttr>();

clang/lib/CodeGen/CodeGenModule.h

@@ -410,6 +410,10 @@ class CodeGenModule : public CodeGenTypeCache {
   /// Used for uniquing of annotation arguments.
   llvm::DenseMap<unsigned, llvm::Constant *> AnnotationArgs;
 
+  /// Used for uniquing of SYCL annotation arguments. SYCL annotations are
+  /// handled differently than regular annotations so they cannot share map.
+  llvm::DenseMap<unsigned, llvm::Constant *> SYCLAnnotationArgs;
+
   llvm::StringMap<llvm::GlobalVariable *> CFConstantStringMap;
 
   llvm::DenseMap<llvm::Constant *, llvm::GlobalVariable *> ConstantStringMap;
@@ -1310,6 +1314,10 @@ class CodeGenModule : public CodeGenTypeCache {
   /// annotations are emitted during finalization of the LLVM code.
   void AddGlobalAnnotations(const ValueDecl *D, llvm::GlobalValue *GV);
 
+  /// Emit additional args of the annotation.
+  llvm::Constant *
+  EmitSYCLAnnotationArgs(const SYCLAddIRAnnotationsMemberAttr *Attr);
+
   /// Add attributes from add_ir_attributes_global_variable on TND to GV.
   void AddGlobalSYCLIRAttributes(llvm::GlobalVariable *GV,
                                  const RecordDecl *RD);

clang/lib/Sema/SemaDecl.cpp

@@ -2816,6 +2816,8 @@ static bool mergeDeclAttribute(Sema &S, NamedDecl *D,
   else if (const auto *A =
                dyn_cast<SYCLAddIRAttributesGlobalVariableAttr>(Attr))
     NewAttr = S.MergeSYCLAddIRAttributesGlobalVariableAttr(D, *A);
+  else if (const auto *A = dyn_cast<SYCLAddIRAnnotationsMemberAttr>(Attr))
+    NewAttr = S.MergeSYCLAddIRAnnotationsMemberAttr(D, *A);
   else if (const auto *A = dyn_cast<ReqdWorkGroupSizeAttr>(Attr))
     NewAttr = S.MergeReqdWorkGroupSizeAttr(D, *A);
   else if (Attr->shouldInheritEvenIfAlreadyPresent() || !DeclHasAttr(D, Attr))

clang/lib/Sema/SemaDeclAttr.cpp

@@ -7911,6 +7911,38 @@ static void handleSYCLAddIRAttributesGlobalVariableAttr(Sema &S, Decl *D,
   S.AddSYCLAddIRAttributesGlobalVariableAttr(D, A, Args);
 }
 
+SYCLAddIRAnnotationsMemberAttr *Sema::MergeSYCLAddIRAnnotationsMemberAttr(
+    Decl *D, const SYCLAddIRAnnotationsMemberAttr &A) {
+  if (const auto *ExistingAttr = D->getAttr<SYCLAddIRAnnotationsMemberAttr>()) {
+    checkSYCLAddIRAttributesMergeability(A, *ExistingAttr, *this);
+    return nullptr;
+  }
+  return A.clone(Context);
+}
+
+void Sema::AddSYCLAddIRAnnotationsMemberAttr(Decl *D,
+                                             const AttributeCommonInfo &CI,
+                                             MutableArrayRef<Expr *> Args) {
+  auto *Attr = SYCLAddIRAnnotationsMemberAttr::Create(Context, Args.data(),
+                                                      Args.size(), CI);
+  if (evaluateAddIRAttributesArgs(Attr->args_begin(), Attr->args_size(), *this,
+                                  CI))
+    return;
+  D->addAttr(Attr);
+}
+
+static void handleSYCLAddIRAnnotationsMemberAttr(Sema &S, Decl *D,
+                                                 const ParsedAttr &A) {
+  llvm::SmallVector<Expr *, 4> Args;
+  Args.reserve(A.getNumArgs());
+  for (unsigned I = 0; I < A.getNumArgs(); I++) {
+    assert(A.getArgAsExpr(I));
+    Args.push_back(A.getArgAsExpr(I));
+  }
+
+  S.AddSYCLAddIRAnnotationsMemberAttr(D, A, Args);
+}
+
 namespace {
 struct IntrinToName {
   uint32_t Id;
@@ -11389,6 +11421,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case ParsedAttr::AT_SYCLAddIRAttributesGlobalVariable:
     handleSYCLAddIRAttributesGlobalVariableAttr(S, D, AL);
     break;
+  case ParsedAttr::AT_SYCLAddIRAnnotationsMember:
+    handleSYCLAddIRAnnotationsMemberAttr(S, D, AL);
+    break;
 
   // Swift attributes.
   case ParsedAttr::AT_SwiftAsyncName:

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

@@ -827,6 +827,18 @@ static void instantiateSYCLAddIRAttributesGlobalVariableAttr(
   S.AddSYCLAddIRAttributesGlobalVariableAttr(New, *A, Args);
 }
 
+static void instantiateSYCLAddIRAnnotationsMemberAttr(
+    Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
+    const SYCLAddIRAnnotationsMemberAttr *A, Decl *New) {
+  EnterExpressionEvaluationContext ConstantEvaluated(
+      S, Sema::ExpressionEvaluationContext::ConstantEvaluated);
+  SmallVector<Expr *, 4> Args;
+  if (S.SubstExprs(ArrayRef<Expr *>(A->args().begin(), A->args().end()),
+                   /*IsCall=*/false, TemplateArgs, Args))
+    return;
+  S.AddSYCLAddIRAnnotationsMemberAttr(New, *A, Args);
+}
+
 static void instantiateWorkGroupSizeHintAttr(
     Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
     const WorkGroupSizeHintAttr *A, Decl *New) {
@@ -1154,6 +1166,12 @@ void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,
           *this, TemplateArgs, SYCLAddIRAttributesGlobalVariable, New);
       continue;
     }
+    if (const auto *SYCLAddIRAnnotationsMember =
+            dyn_cast<SYCLAddIRAnnotationsMemberAttr>(TmplAttr)) {
+      instantiateSYCLAddIRAnnotationsMemberAttr(
+          *this, TemplateArgs, SYCLAddIRAnnotationsMember, New);
+      continue;
+    }
     if (const auto *A = dyn_cast<WorkGroupSizeHintAttr>(TmplAttr)) {
       instantiateWorkGroupSizeHintAttr(*this, TemplateArgs, A, New);
       continue;