Unique stable name reimpl

clang/docs/LanguageExtensions.rst

@@ -1766,7 +1766,7 @@ correctly in any circumstances. It can be used if:
   metaprogramming algorithms to be able to specify/detect types generically.
 
 - the generated kernel binary does not contain indirect calls because they
-  are eliminated using compiler optimizations e.g. devirtualization. 
+  are eliminated using compiler optimizations e.g. devirtualization.
 
 - the selected target supports the function pointer like functionality e.g.
   most CPU targets.
@@ -2311,6 +2311,30 @@ argument.
   int *pb =__builtin_preserve_access_index(&v->c[3].b);
   __builtin_preserve_access_index(v->j);
 
+``__builtin_unique_stable_name``
+------------------------
+
+``__builtin_unique_stable_name()`` is a builtin that takes a type or expression and
+produces a string literal containing a unique name for the type (or type of the
+expression) that is stable across split compilations.
+
+In cases where the split compilation needs to share a unique token for a type
+across the boundary (such as in an offloading situation), this name can be used
+for lookup purposes.
+
+This builtin is superior to RTTI for this purpose for two reasons.  First, this
+value is computed entirely at compile time, so it can be used in constant
+expressions. Second, this value encodes lambda functions based on line-number
+rather than the order in which it appears in a function. This is valuable
+because it is stable in cases where an unrelated lambda is introduced
+conditionally in the same function.
+
+The current implementation of this builtin uses a slightly modified Itanium
+Mangler to produce the unique name. The lambda ordinal is replaced with one or
+more line/column pairs in the format ``LINE->COL``, separated with a ``~``
+character. Typically, only one pair will be included, however in the case of
+macro expansions the entire macro expansion stack is expressed.
+
 Multiprecision Arithmetic Builtins
 ----------------------------------
 
@@ -2505,7 +2529,7 @@ Guaranteed inlined copy
 ``__builtin_memcpy_inline`` has been designed as a building block for efficient
 ``memcpy`` implementations. It is identical to ``__builtin_memcpy`` but also
 guarantees not to call any external functions. See LLVM IR `llvm.memcpy.inline
-<https://llvm.org/docs/LangRef.html#llvm-memcpy-inline-intrinsic>`_ intrinsic 
+<https://llvm.org/docs/LangRef.html#llvm-memcpy-inline-intrinsic>`_ intrinsic
 for more information.
 
 This is useful to implement a custom version of ``memcpy``, implement a

clang/include/clang/AST/ComputeDependence.h

@@ -78,6 +78,7 @@ class MaterializeTemporaryExpr;
 class CXXFoldExpr;
 class TypeTraitExpr;
 class ConceptSpecializationExpr;
+class UniqueStableNameExpr;
 class PredefinedExpr;
 class CallExpr;
 class OffsetOfExpr;
@@ -165,6 +166,7 @@ ExprDependence computeDependence(TypeTraitExpr *E);
 ExprDependence computeDependence(ConceptSpecializationExpr *E,
                                  bool ValueDependent);
 
+ExprDependence computeDependence(UniqueStableNameExpr *E);
 ExprDependence computeDependence(PredefinedExpr *E);
 ExprDependence computeDependence(CallExpr *E, llvm::ArrayRef<Expr *> PreArgs);
 ExprDependence computeDependence(OffsetOfExpr *E);

clang/include/clang/AST/Expr.h

@@ -2037,6 +2037,112 @@ class PredefinedExpr final
   }
 };
 
+// This represents a use of the __builtin_unique_stable_name, which takes either
+// a type-id or an expression, and at CodeGen time emits a unique string
+// representation of the type (or type of the expression) in a way that permits
+// us to properly encode information about the SYCL Kernels.
+class UniqueStableNameExpr final
+    : public Expr,
+      private llvm::TrailingObjects<UniqueStableNameExpr, Stmt *,
+                                    TypeSourceInfo *> {
+  friend class ASTStmtReader;
+  friend TrailingObjects;
+  SourceLocation OpLoc, LParen, RParen;
+  // Note: We store a Stmt* instead of the Expr* so that we can implement
+  // 'children'.
+  enum class ParamKind { Type, Expr };
+  ParamKind Kind;
+
+  UniqueStableNameExpr(EmptyShell Empty, QualType ResultTy, bool IsExpr);
+  UniqueStableNameExpr(SourceLocation OpLoc, SourceLocation LParen,
+                       SourceLocation RParen, QualType ResultTy,
+                       TypeSourceInfo *TSI);
+  UniqueStableNameExpr(SourceLocation OpLoc, SourceLocation LParen,
+                       SourceLocation RParen, QualType ResultTy, Expr *E);
+
+  size_t numTrailingObjects(OverloadToken<TypeSourceInfo *>) const {
+    return Kind == ParamKind::Type ? 1 : 0;
+  }
+  size_t numTrailingObjects(OverloadToken<Stmt *>) const {
+    return Kind == ParamKind::Expr ? 1 : 0;
+  }
+  void setTypeSourceInfo(TypeSourceInfo *Ty) {
+    assert(Kind == ParamKind::Type &&
+           "TypeSourceInfo only valid for UniqueStableName of a Type");
+    *getTrailingObjects<TypeSourceInfo *>() = Ty;
+  }
+  void setExpr(Expr *E) {
+    assert(Kind == ParamKind::Expr &&
+           "Expr only valid for UniqueStableName of an Expr");
+    assert(E->isInstantiationDependent() &&
+           "Expr type only valid if the expr is dependent");
+    *getTrailingObjects<Stmt *>() = E;
+  }
+
+  void setLocation(SourceLocation L) { OpLoc = L; }
+  void setLParenLocation(SourceLocation L) { LParen = L; }
+  void setRParenLocation(SourceLocation L) { RParen = L; }
+
+public:
+  TypeSourceInfo *getTypeSourceInfo() {
+    assert(Kind == ParamKind::Type &&
+           "TypeSourceInfo only valid for UniqueStableName of a Type");
+    return *getTrailingObjects<TypeSourceInfo *>();
+  }
+
+  const TypeSourceInfo *getTypeSourceInfo() const {
+    assert(Kind == ParamKind::Type &&
+           "TypeSourceInfo only valid for UniqueStableName of a Type");
+    return *getTrailingObjects<TypeSourceInfo *>();
+  }
+
+  Expr *getExpr() {
+    assert(Kind == ParamKind::Expr &&
+           "Expr only valid for UniqueStableName of an Expr");
+    return static_cast<Expr *>(*getTrailingObjects<Stmt *>());
+  }
+
+  const Expr *getExpr() const {
+    assert(Kind == ParamKind::Expr &&
+           "Expr only valid for UniqueStableName of an Expr");
+    return static_cast<Expr *>(*getTrailingObjects<Stmt *>());
+  }
+
+  bool isExpr() const { return Kind == ParamKind::Expr; }
+
+  bool isTypeSourceInfo() const { return Kind == ParamKind::Type; }
+
+  static UniqueStableNameExpr *
+  Create(const ASTContext &Ctx, SourceLocation OpLoc, SourceLocation LParen,
+         SourceLocation RParen, TypeSourceInfo *TSI);
+
+  static UniqueStableNameExpr *Create(const ASTContext &Ctx,
+                                      SourceLocation OpLoc,
+                                      SourceLocation LParen,
+                                      SourceLocation RParen, Expr *E);
+  static UniqueStableNameExpr *CreateEmpty(const ASTContext &Ctx, bool IsExpr);
+
+  SourceLocation getBeginLoc() const { return getLocation(); }
+  SourceLocation getEndLoc() const { return RParen; }
+  SourceLocation getLocation() const { return OpLoc; }
+  SourceLocation getLParenLocation() const { return LParen; }
+  SourceLocation getRParenLocation() const { return RParen; }
+
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() == UniqueStableNameExprClass;
+  }
+
+  // Iterators
+  child_range children() {
+    return child_range(getTrailingObjects<Stmt *>(),
+                       getTrailingObjects<Stmt *>() + isExpr());
+  }
+  const_child_range children() const {
+    return const_child_range(getTrailingObjects<Stmt *>(),
+                             getTrailingObjects<Stmt *>() + isExpr());
+  }
+};
+
 /// ParenExpr - This represents a parethesized expression, e.g. "(1)".  This
 /// AST node is only formed if full location information is requested.
 class ParenExpr : public Expr {

clang/include/clang/AST/RecursiveASTVisitor.h

@@ -2636,6 +2636,12 @@ DEF_TRAVERSE_STMT(ObjCBridgedCastExpr, {
 DEF_TRAVERSE_STMT(ObjCAvailabilityCheckExpr, {})
 DEF_TRAVERSE_STMT(ParenExpr, {})
 DEF_TRAVERSE_STMT(ParenListExpr, {})
+DEF_TRAVERSE_STMT(UniqueStableNameExpr, {
+  if (S->isExpr())
+    TRY_TO(TraverseStmt(S->getExpr()));
+  else
+    TRY_TO(TraverseTypeLoc(S->getTypeSourceInfo()->getTypeLoc()));
+})
 DEF_TRAVERSE_STMT(PredefinedExpr, {})
 DEF_TRAVERSE_STMT(ShuffleVectorExpr, {})
 DEF_TRAVERSE_STMT(ConvertVectorExpr, {})

clang/include/clang/Basic/StmtNodes.td

@@ -57,6 +57,7 @@ def CoreturnStmt : StmtNode<Stmt>;
 // Expressions
 def Expr : StmtNode<ValueStmt, 1>;
 def PredefinedExpr : StmtNode<Expr>;
+def UniqueStableNameExpr : StmtNode<Expr>;
 def DeclRefExpr : StmtNode<Expr>;
 def IntegerLiteral : StmtNode<Expr>;
 def FixedPointLiteral : StmtNode<Expr>;

clang/include/clang/Basic/TokenKinds.def

@@ -699,6 +699,7 @@ ALIAS("__char16_t"   , char16_t     , KEYCXX)
 ALIAS("__char32_t"   , char32_t     , KEYCXX)
 KEYWORD(__builtin_bit_cast          , KEYALL)
 KEYWORD(__builtin_available         , KEYALL)
+KEYWORD(__builtin_unique_stable_name, KEYALL)
 
 // Clang-specific keywords enabled only in testing.
 TESTING_KEYWORD(__unknown_anytype , KEYALL)

clang/include/clang/Parse/Parser.h

@@ -1797,6 +1797,7 @@ class Parser : public CodeCompletionHandler {
   ExprResult ParsePostfixExpressionSuffix(ExprResult LHS);
   ExprResult ParseUnaryExprOrTypeTraitExpression();
   ExprResult ParseBuiltinPrimaryExpression();
+  ExprResult ParseUniqueStableNameExpression();
 
   ExprResult ParseExprAfterUnaryExprOrTypeTrait(const Token &OpTok,
                                                      bool &isCastExpr,

clang/include/clang/Sema/Sema.h

@@ -5176,6 +5176,21 @@ class Sema final {
   ExprResult ActOnPredefinedExpr(SourceLocation Loc, tok::TokenKind Kind);
   ExprResult ActOnIntegerConstant(SourceLocation Loc, uint64_t Val);
 
+  ExprResult BuildUniqueStableNameExpr(SourceLocation OpLoc,
+                                       SourceLocation LParen,
+                                       SourceLocation RParen,
+                                       TypeSourceInfo *TSI);
+  ExprResult BuildUniqueStableNameExpr(SourceLocation OpLoc,
+                                       SourceLocation LParen,
+                                       SourceLocation RParen, Expr *E);
+  ExprResult ActOnUniqueStableNameExpr(SourceLocation OpLoc,
+                                       SourceLocation LParen,
+                                       SourceLocation RParen,
+                                       ParsedType ParsedTy);
+  ExprResult ActOnUniqueStableNameExpr(SourceLocation OpLoc,
+                                       SourceLocation LParen,
+                                       SourceLocation RParen, Expr *Operand);
+
   bool CheckLoopHintExpr(Expr *E, SourceLocation Loc);
 
   ExprResult ActOnNumericConstant(const Token &Tok, Scope *UDLScope = nullptr);

clang/include/clang/Serialization/ASTBitCodes.h

@@ -1960,6 +1960,9 @@ enum StmtCode {
 
   // FixedPointLiteral
   EXPR_FIXEDPOINT_LITERAL,
+
+  // UniqueStableNameExpr
+  EXPR_UNIQUESTABLENAME,
 };
 
 /// The kinds of designators that can occur in a

clang/lib/AST/ComputeDependence.cpp

@@ -556,6 +556,12 @@ ExprDependence clang::computeDependence(RecoveryExpr *E) {
   return D;
 }
 
+ExprDependence clang::computeDependence(UniqueStableNameExpr *E) {
+  if (E->isExpr())
+    return E->getExpr()->getDependence();
+  return toExprDependence(E->getTypeSourceInfo()->getType()->getDependence());
+}
+
 ExprDependence clang::computeDependence(PredefinedExpr *E) {
   return toExprDependence(E->getType()->getDependence()) &
          ~ExprDependence::UnexpandedPack;

clang/lib/AST/Expr.cpp

@@ -503,6 +503,68 @@ SourceLocation DeclRefExpr::getEndLoc() const {
   return getNameInfo().getEndLoc();
 }
 
+UniqueStableNameExpr::UniqueStableNameExpr(SourceLocation OpLoc,
+                                           SourceLocation LParen,
+                                           SourceLocation RParen,
+                                           QualType ResultTy,
+                                           TypeSourceInfo *TSI)
+    : Expr(UniqueStableNameExprClass, ResultTy, VK_LValue, OK_Ordinary),
+      OpLoc(OpLoc), LParen(LParen), RParen(RParen), Kind(ParamKind::Type) {
+  setTypeSourceInfo(TSI);
+  // Fixme: Do we have to do anything to make this work?
+  setDependence(computeDependence(this));
+}
+
+UniqueStableNameExpr::UniqueStableNameExpr(EmptyShell Empty, QualType ResultTy,
+                                           bool IsExpr)
+    : Expr(UniqueStableNameExprClass, ResultTy, VK_LValue, OK_Ordinary) {
+  Kind = IsExpr ? ParamKind::Expr : ParamKind::Expr;
+}
+
+UniqueStableNameExpr::UniqueStableNameExpr(SourceLocation OpLoc,
+                                           SourceLocation LParen,
+                                           SourceLocation RParen,
+                                           QualType ResultTy, Expr *E)
+    : Expr(UniqueStableNameExprClass, ResultTy, VK_LValue, OK_Ordinary),
+      OpLoc(OpLoc), LParen(LParen), RParen(RParen), Kind(ParamKind::Expr) {
+  setExpr(E);
+  setDependence(computeDependence(this));
+}
+
+UniqueStableNameExpr *UniqueStableNameExpr::Create(const ASTContext &Ctx,
+                                                   SourceLocation OpLoc,
+                                                   SourceLocation LParen,
+                                                   SourceLocation RParen,
+                                                   Expr *E) {
+  assert(E->isInstantiationDependent() &&
+         "Expr type only valid if the expr is dependent");
+  void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1, 0),
+                           alignof(UniqueStableNameExpr));
+
+  QualType ResultTy = Ctx.getPointerType(Ctx.CharTy.withConst());
+  return new (Mem) UniqueStableNameExpr(OpLoc, LParen, RParen, ResultTy, E);
+}
+
+UniqueStableNameExpr *UniqueStableNameExpr::Create(const ASTContext &Ctx,
+                                                   SourceLocation OpLoc,
+                                                   SourceLocation LParen,
+                                                   SourceLocation RParen,
+                                                   TypeSourceInfo *TSI) {
+  void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1, 0),
+                           alignof(UniqueStableNameExpr));
+  QualType ResultTy = Ctx.getPointerType(Ctx.CharTy.withConst());
+  return new (Mem) UniqueStableNameExpr(OpLoc, LParen, RParen, ResultTy, TSI);
+}
+
+UniqueStableNameExpr *UniqueStableNameExpr::CreateEmpty(const ASTContext &Ctx,
+                                                        bool IsExpr) {
+  void *Mem =
+      Ctx.Allocate(totalSizeToAlloc<Stmt *, TypeSourceInfo *>(IsExpr, !IsExpr),
+                   alignof(UniqueStableNameExpr));
+  QualType ResultTy = Ctx.getPointerType(Ctx.CharTy.withConst());
+  return new (Mem) UniqueStableNameExpr(EmptyShell(), ResultTy, IsExpr);
+}
+
 PredefinedExpr::PredefinedExpr(SourceLocation L, QualType FNTy, IdentKind IK,
                                StringLiteral *SL)
     : Expr(PredefinedExprClass, FNTy, VK_LValue, OK_Ordinary) {
@@ -3308,6 +3370,7 @@ bool Expr::HasSideEffects(const ASTContext &Ctx,
   case SourceLocExprClass:
   case ConceptSpecializationExprClass:
   case RequiresExprClass:
+  case UniqueStableNameExprClass:
     // These never have a side-effect.
     return false;
 

clang/lib/AST/ExprClassification.cpp

@@ -433,6 +433,9 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
   case Expr::CoawaitExprClass:
   case Expr::CoyieldExprClass:
     return ClassifyInternal(Ctx, cast<CoroutineSuspendExpr>(E)->getResumeExpr());
+  case Expr::UniqueStableNameExprClass:
+    // TODO: ERICH! Figure out how to handle this.
+    break;
   }
 
   llvm_unreachable("unhandled expression kind in classification");

clang/lib/AST/ExprConstant.cpp

@@ -15154,6 +15154,7 @@ static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) {
   case Expr::CoawaitExprClass:
   case Expr::DependentCoawaitExprClass:
   case Expr::CoyieldExprClass:
+  case Expr::UniqueStableNameExprClass:
     return ICEDiag(IK_NotICE, E->getBeginLoc());
 
   case Expr::InitListExprClass: {

clang/lib/AST/ItaniumMangle.cpp

@@ -4069,6 +4069,7 @@ void CXXNameMangler::mangleExpression(const Expr *E, unsigned Arity,
   case Expr::OMPArrayShapingExprClass:
   case Expr::OMPIteratorExprClass:
   case Expr::CXXInheritedCtorInitExprClass:
+  case Expr::UniqueStableNameExprClass:
     llvm_unreachable("unexpected statement kind");
 
   case Expr::ConstantExprClass:

clang/lib/AST/StmtPrinter.cpp

@@ -1077,6 +1077,16 @@ void StmtPrinter::VisitObjCSubscriptRefExpr(ObjCSubscriptRefExpr *Node) {
   OS << "]";
 }
 
+void StmtPrinter::VisitUniqueStableNameExpr(UniqueStableNameExpr *Node) {
+  // FIXME: Is this the correct thing?
+  OS << "__builtin_unique_stable_name(";
+  if (Node->isExpr())
+    PrintExpr(Node->getExpr());
+  else
+    Node->getTypeSourceInfo()->getType().print(OS, Policy);
+  OS << ")";
+}
+
 void StmtPrinter::VisitPredefinedExpr(PredefinedExpr *Node) {
   OS << PredefinedExpr::getIdentKindName(Node->getIdentKind());
 }