[llvm] r252811 - [IR] Add support for empty tokens

Reid Kleckner via llvm-commits llvm-commits at lists.llvm.org
Fri Nov 13 14:06:54 PST 2015


We end up leaking TheNoneToken. I took a look, but fixing it wasn't
straightforward.

On Wed, Nov 11, 2015 at 1:57 PM, David Majnemer via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: majnemer
> Date: Wed Nov 11 15:57:16 2015
> New Revision: 252811
>
> URL: http://llvm.org/viewvc/llvm-project?rev=252811&view=rev
> Log:
> [IR] Add support for empty tokens
>
> When working with tokens, it is often the case that one has instructions
> which consume a token and produce a new token.  Currently, we have no
> mechanism to represent an initial token state.
>
> Instead, we can create a notional "empty token" by inventing a new
> constant which captures the semantics we would like.  This new constant
> is called ConstantTokenNone and is written textually as "token none".
>
> Differential Revision: http://reviews.llvm.org/D14581
>
> Modified:
>     llvm/trunk/docs/LangRef.rst
>     llvm/trunk/include/llvm-c/Core.h
>     llvm/trunk/include/llvm/IR/Constants.h
>     llvm/trunk/include/llvm/IR/Value.def
>     llvm/trunk/lib/AsmParser/LLLexer.cpp
>     llvm/trunk/lib/AsmParser/LLParser.cpp
>     llvm/trunk/lib/AsmParser/LLParser.h
>     llvm/trunk/lib/AsmParser/LLToken.h
>     llvm/trunk/lib/IR/AsmWriter.cpp
>     llvm/trunk/lib/IR/Constants.cpp
>     llvm/trunk/lib/IR/LLVMContextImpl.cpp
>     llvm/trunk/lib/IR/LLVMContextImpl.h
>     llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp
>     llvm/trunk/test/Assembler/token.ll
>
> Modified: llvm/trunk/docs/LangRef.rst
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/docs/LangRef.rst (original)
> +++ llvm/trunk/docs/LangRef.rst Wed Nov 11 15:57:16 2015
> @@ -2434,6 +2434,9 @@ Simple Constants
>  **Null pointer constants**
>      The identifier '``null``' is recognized as a null pointer constant
>      and must be of :ref:`pointer type <t_pointer>`.
> +**Token constants**
> +    The identifier '``none``' is recognized as an empty token constant
> +    and must be of :ref:`token type <t_token>`.
>
>  The one non-intuitive notation for constants is the hexadecimal form of
>  floating point constants. For example, the form
>
> Modified: llvm/trunk/include/llvm-c/Core.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm-c/Core.h?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm-c/Core.h (original)
> +++ llvm/trunk/include/llvm-c/Core.h Wed Nov 11 15:57:16 2015
> @@ -1185,6 +1185,7 @@ LLVMTypeRef LLVMX86MMXType(void);
>        macro(ConstantInt)                    \
>        macro(ConstantPointerNull)            \
>        macro(ConstantStruct)                 \
> +      macro(ConstantTokenNone)              \
>        macro(ConstantVector)                 \
>        macro(GlobalValue)                    \
>          macro(GlobalAlias)                  \
>
> Modified: llvm/trunk/include/llvm/IR/Constants.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Constants.h?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/IR/Constants.h (original)
> +++ llvm/trunk/include/llvm/IR/Constants.h Wed Nov 11 15:57:16 2015
> @@ -795,7 +795,32 @@ public:
>    }
>  };
>
>
> +//===----------------------------------------------------------------------===//
> +/// ConstantTokenNone - a constant token which is empty
> +///
> +class ConstantTokenNone : public Constant {
> +  void *operator new(size_t, unsigned) = delete;
> +  ConstantTokenNone(const ConstantTokenNone &) = delete;
> +
> +  friend class Constant;
> +  void destroyConstantImpl();
> +  Value *handleOperandChangeImpl(Value *From, Value *To, Use *U);
> +
> +protected:
> +  explicit ConstantTokenNone(LLVMContext &Context)
> +      : Constant(Type::getTokenTy(Context), ConstantTokenNoneVal,
> nullptr, 0) {}
> +  // allocate space for exactly zero operands
> +  void *operator new(size_t s) { return User::operator new(s, 0); }
>
> +public:
> +  /// Return the ConstantTokenNone.
> +  static ConstantTokenNone *get(LLVMContext &Context);
> +
> +  /// @brief Methods to support type inquiry through isa, cast, and
> dyn_cast.
> +  static bool classof(const Value *V) {
> +    return V->getValueID() == ConstantTokenNoneVal;
> +  }
> +};
>
>  /// BlockAddress - The address of a basic block.
>  ///
>
> Modified: llvm/trunk/include/llvm/IR/Value.def
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Value.def?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/IR/Value.def (original)
> +++ llvm/trunk/include/llvm/IR/Value.def Wed Nov 11 15:57:16 2015
> @@ -70,6 +70,7 @@ HANDLE_CONSTANT(ConstantArray)
>  HANDLE_CONSTANT(ConstantStruct)
>  HANDLE_CONSTANT(ConstantVector)
>  HANDLE_CONSTANT(ConstantPointerNull)
> +HANDLE_CONSTANT(ConstantTokenNone)
>
>  HANDLE_METADATA_VALUE(MetadataAsValue)
>  HANDLE_INLINE_ASM_VALUE(InlineAsm)
> @@ -79,7 +80,7 @@ HANDLE_INSTRUCTION(Instruction)
>  // don't add new values here!
>
>  HANDLE_CONSTANT_MARKER(ConstantFirstVal, Function)
> -HANDLE_CONSTANT_MARKER(ConstantLastVal, ConstantPointerNull)
> +HANDLE_CONSTANT_MARKER(ConstantLastVal, ConstantTokenNone)
>
>  #undef HANDLE_GLOBAL_VALUE
>  #undef HANDLE_CONSTANT
>
> Modified: llvm/trunk/lib/AsmParser/LLLexer.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/AsmParser/LLLexer.cpp?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/AsmParser/LLLexer.cpp (original)
> +++ llvm/trunk/lib/AsmParser/LLLexer.cpp Wed Nov 11 15:57:16 2015
> @@ -523,6 +523,7 @@ lltok::Kind LLLexer::LexIdentifier() {
>    KEYWORD(zeroinitializer);
>    KEYWORD(undef);
>    KEYWORD(null);
> +  KEYWORD(none);
>    KEYWORD(to);
>    KEYWORD(caller);
>    KEYWORD(tail);
>
> Modified: llvm/trunk/lib/AsmParser/LLParser.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/AsmParser/LLParser.cpp?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/AsmParser/LLParser.cpp (original)
> +++ llvm/trunk/lib/AsmParser/LLParser.cpp Wed Nov 11 15:57:16 2015
> @@ -2622,6 +2622,7 @@ bool LLParser::ParseValID(ValID &ID, Per
>    case lltok::kw_null: ID.Kind = ValID::t_Null; break;
>    case lltok::kw_undef: ID.Kind = ValID::t_Undef; break;
>    case lltok::kw_zeroinitializer: ID.Kind = ValID::t_Zero; break;
> +  case lltok::kw_none: ID.Kind = ValID::t_None; break;
>
>    case lltok::lbrace: {
>      // ValID ::= '{' ConstVector '}'
> @@ -4255,6 +4256,11 @@ bool LLParser::ConvertValIDToValue(Type
>        return Error(ID.Loc, "invalid type for null constant");
>      V = Constant::getNullValue(Ty);
>      return false;
> +  case ValID::t_None:
> +    if (!Ty->isTokenTy())
> +      return Error(ID.Loc, "invalid type for none constant");
> +    V = Constant::getNullValue(Ty);
> +    return false;
>    case ValID::t_Constant:
>      if (ID.ConstantVal->getType() != Ty)
>        return Error(ID.Loc, "constant expression type mismatch");
>
> Modified: llvm/trunk/lib/AsmParser/LLParser.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/AsmParser/LLParser.h?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/AsmParser/LLParser.h (original)
> +++ llvm/trunk/lib/AsmParser/LLParser.h Wed Nov 11 15:57:16 2015
> @@ -46,15 +46,15 @@ namespace llvm {
>    /// or a symbolic (%var) reference.  This is just a discriminated union.
>    struct ValID {
>      enum {
> -      t_LocalID, t_GlobalID,      // ID in UIntVal.
> -      t_LocalName, t_GlobalName,  // Name in StrVal.
> -      t_APSInt, t_APFloat,        // Value in APSIntVal/APFloatVal.
> -      t_Null, t_Undef, t_Zero,    // No value.
> -      t_EmptyArray,               // No value:  []
> -      t_Constant,                 // Value in ConstantVal.
> -      t_InlineAsm,                // Value in FTy/StrVal/StrVal2/UIntVal.
> -      t_ConstantStruct,           // Value in ConstantStructElts.
> -      t_PackedConstantStruct      // Value in ConstantStructElts.
> +      t_LocalID, t_GlobalID,           // ID in UIntVal.
> +      t_LocalName, t_GlobalName,       // Name in StrVal.
> +      t_APSInt, t_APFloat,             // Value in APSIntVal/APFloatVal.
> +      t_Null, t_Undef, t_Zero, t_None, // No value.
> +      t_EmptyArray,                    // No value:  []
> +      t_Constant,                      // Value in ConstantVal.
> +      t_InlineAsm,                     // Value in
> FTy/StrVal/StrVal2/UIntVal.
> +      t_ConstantStruct,                // Value in ConstantStructElts.
> +      t_PackedConstantStruct           // Value in ConstantStructElts.
>      } Kind = t_LocalID;
>
>      LLLexer::LocTy Loc;
>
> Modified: llvm/trunk/lib/AsmParser/LLToken.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/AsmParser/LLToken.h?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/AsmParser/LLToken.h (original)
> +++ llvm/trunk/lib/AsmParser/LLToken.h Wed Nov 11 15:57:16 2015
> @@ -49,7 +49,7 @@ namespace lltok {
>      kw_external, kw_thread_local,
>      kw_localdynamic, kw_initialexec, kw_localexec,
>      kw_zeroinitializer,
> -    kw_undef, kw_null,
> +    kw_undef, kw_null, kw_none,
>      kw_to,
>      kw_caller,
>      kw_tail,
>
> Modified: llvm/trunk/lib/IR/AsmWriter.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/AsmWriter.cpp?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/IR/AsmWriter.cpp (original)
> +++ llvm/trunk/lib/IR/AsmWriter.cpp Wed Nov 11 15:57:16 2015
> @@ -1328,6 +1328,11 @@ static void WriteConstantInternal(raw_os
>      return;
>    }
>
> +  if (isa<ConstantTokenNone>(CV)) {
> +    Out << "none";
> +    return;
> +  }
> +
>    if (isa<UndefValue>(CV)) {
>      Out << "undef";
>      return;
>
> Modified: llvm/trunk/lib/IR/Constants.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Constants.cpp?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/IR/Constants.cpp (original)
> +++ llvm/trunk/lib/IR/Constants.cpp Wed Nov 11 15:57:16 2015
> @@ -81,8 +81,10 @@ bool Constant::isNullValue() const {
>    if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
>      return CFP->isZero() && !CFP->isNegative();
>
> -  // constant zero is zero for aggregates and cpnull is null for pointers.
> -  return isa<ConstantAggregateZero>(this) ||
> isa<ConstantPointerNull>(this);
> +  // constant zero is zero for aggregates, cpnull is null for pointers,
> none for
> +  // tokens.
> +  return isa<ConstantAggregateZero>(this) ||
> isa<ConstantPointerNull>(this) ||
> +         isa<ConstantTokenNone>(this);
>  }
>
>  bool Constant::isAllOnesValue() const {
> @@ -204,6 +206,8 @@ Constant *Constant::getNullValue(Type *T
>    case Type::ArrayTyID:
>    case Type::VectorTyID:
>      return ConstantAggregateZero::get(Ty);
> +  case Type::TokenTyID:
> +    return ConstantTokenNone::get(Ty->getContext());
>    default:
>      // Function, Label, or Opaque type?
>      llvm_unreachable("Cannot create a null constant of that type!");
> @@ -1170,6 +1174,17 @@ Constant *ConstantVector::getSplat(unsig
>    return get(Elts);
>  }
>
> +ConstantTokenNone *ConstantTokenNone::get(LLVMContext &Context) {
> +  LLVMContextImpl *pImpl = Context.pImpl;
> +  if (!pImpl->TheNoneToken)
> +    pImpl->TheNoneToken = new ConstantTokenNone(Context);
> +  return pImpl->TheNoneToken;
> +}
> +
> +/// Remove the constant from the constant table.
> +void ConstantTokenNone::destroyConstantImpl() {
> +  llvm_unreachable("You can't ConstantTokenNone->destroyConstantImpl()!");
> +}
>
>  // Utility function for determining if a ConstantExpr is a CastOp or not.
> This
>  // can't be inline because we don't want to #include Instruction.h into
> @@ -2875,6 +2890,11 @@ Value *ConstantFP::handleOperandChangeIm
>    llvm_unreachable("Unsupported class for handleOperandChange()!");
>  }
>
> +Value *ConstantTokenNone::handleOperandChangeImpl(Value *From, Value *To,
> +                                                  Use *U) {
> +  llvm_unreachable("Unsupported class for handleOperandChange()!");
> +}
> +
>  Value *UndefValue::handleOperandChangeImpl(Value *From, Value *To, Use
> *U) {
>    llvm_unreachable("Unsupported class for handleOperandChange()!");
>  }
>
> Modified: llvm/trunk/lib/IR/LLVMContextImpl.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/LLVMContextImpl.cpp?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/IR/LLVMContextImpl.cpp (original)
> +++ llvm/trunk/lib/IR/LLVMContextImpl.cpp Wed Nov 11 15:57:16 2015
> @@ -21,6 +21,7 @@ using namespace llvm;
>
>  LLVMContextImpl::LLVMContextImpl(LLVMContext &C)
>    : TheTrueVal(nullptr), TheFalseVal(nullptr),
> +    TheNoneToken(nullptr),
>      VoidTy(C, Type::VoidTyID),
>      LabelTy(C, Type::LabelTyID),
>      HalfTy(C, Type::HalfTyID),
>
> Modified: llvm/trunk/lib/IR/LLVMContextImpl.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/LLVMContextImpl.h?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/IR/LLVMContextImpl.h (original)
> +++ llvm/trunk/lib/IR/LLVMContextImpl.h Wed Nov 11 15:57:16 2015
> @@ -924,6 +924,8 @@ public:
>    ConstantInt *TheTrueVal;
>    ConstantInt *TheFalseVal;
>
> +  ConstantTokenNone *TheNoneToken;
> +
>    // Basic type instances.
>    Type VoidTy, LabelTy, HalfTy, FloatTy, DoubleTy, MetadataTy, TokenTy;
>    Type X86_FP80Ty, FP128Ty, PPC_FP128Ty, X86_MMXTy;
>
> Modified: llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp (original)
> +++ llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp Wed Nov 11 15:57:16
> 2015
> @@ -656,7 +656,9 @@ int FunctionComparator::cmpConstants(con
>    }
>
>    switch (L->getValueID()) {
> -  case Value::UndefValueVal: return TypesRes;
> +  case Value::UndefValueVal:
> +  case Value::ConstantTokenNoneVal:
> +    return TypesRes;
>    case Value::ConstantIntVal: {
>      const APInt &LInt = cast<ConstantInt>(L)->getValue();
>      const APInt &RInt = cast<ConstantInt>(R)->getValue();
>
> Modified: llvm/trunk/test/Assembler/token.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Assembler/token.ll?rev=252811&r1=252810&r2=252811&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/Assembler/token.ll (original)
> +++ llvm/trunk/test/Assembler/token.ll Wed Nov 11 15:57:16 2015
> @@ -4,3 +4,8 @@
>
>  ; CHECK: declare void @llvm.token.foobar(token)
>  declare void @llvm.token.foobar(token)
> +
> +define void @f() {
> +  call void @llvm.token.foobar(token none)
> +  ret void
> +}
>
>
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