LCOV - code coverage report
Current view: top level - include/llvm/IR - Constant.h (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 6 6 100.0 %
Date: 2017-09-14 15:23:50 Functions: 0 0 -
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===-- llvm/Constant.h - Constant class definition -------------*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : // This file contains the declaration of the Constant class.
      11             : //
      12             : //===----------------------------------------------------------------------===//
      13             : 
      14             : #ifndef LLVM_IR_CONSTANT_H
      15             : #define LLVM_IR_CONSTANT_H
      16             : 
      17             : #include "llvm/IR/User.h"
      18             : #include "llvm/IR/Value.h"
      19             : #include "llvm/Support/Casting.h"
      20             : 
      21             : namespace llvm {
      22             : 
      23             : class APInt;
      24             : 
      25             : /// This is an important base class in LLVM. It provides the common facilities
      26             : /// of all constant values in an LLVM program. A constant is a value that is
      27             : /// immutable at runtime. Functions are constants because their address is
      28             : /// immutable. Same with global variables.
      29             : ///
      30             : /// All constants share the capabilities provided in this class. All constants
      31             : /// can have a null value. They can have an operand list. Constants can be
      32             : /// simple (integer and floating point values), complex (arrays and structures),
      33             : /// or expression based (computations yielding a constant value composed of
      34             : /// only certain operators and other constant values).
      35             : ///
      36             : /// Note that Constants are immutable (once created they never change)
      37             : /// and are fully shared by structural equivalence.  This means that two
      38             : /// structurally equivalent constants will always have the same address.
      39             : /// Constants are created on demand as needed and never deleted: thus clients
      40             : /// don't have to worry about the lifetime of the objects.
      41             : /// @brief LLVM Constant Representation
      42     2871413 : class Constant : public User {
      43             : protected:
      44             :   Constant(Type *ty, ValueTy vty, Use *Ops, unsigned NumOps)
      45     3769932 :     : User(ty, vty, Ops, NumOps) {}
      46             : 
      47             : public:
      48             :   void operator=(const Constant &) = delete;
      49             :   Constant(const Constant &) = delete;
      50             : 
      51             :   /// Return true if this is the value that would be returned by getNullValue.
      52             :   bool isNullValue() const;
      53             : 
      54             :   /// Returns true if the value is one.
      55             :   bool isOneValue() const;
      56             : 
      57             :   /// Return true if this is the value that would be returned by
      58             :   /// getAllOnesValue.
      59             :   bool isAllOnesValue() const;
      60             : 
      61             :   /// Return true if the value is what would be returned by
      62             :   /// getZeroValueForNegation.
      63             :   bool isNegativeZeroValue() const;
      64             : 
      65             :   /// Return true if the value is negative zero or null value.
      66             :   bool isZeroValue() const;
      67             : 
      68             :   /// Return true if the value is not the smallest signed value.
      69             :   bool isNotMinSignedValue() const;
      70             : 
      71             :   /// Return true if the value is the smallest signed value.
      72             :   bool isMinSignedValue() const;
      73             : 
      74             :   /// Return true if evaluation of this constant could trap. This is true for
      75             :   /// things like constant expressions that could divide by zero.
      76             :   bool canTrap() const;
      77             : 
      78             :   /// Return true if the value can vary between threads.
      79             :   bool isThreadDependent() const;
      80             : 
      81             :   /// Return true if the value is dependent on a dllimport variable.
      82             :   bool isDLLImportDependent() const;
      83             : 
      84             :   /// Return true if the constant has users other than constant expressions and
      85             :   /// other dangling things.
      86             :   bool isConstantUsed() const;
      87             : 
      88             :   /// This method classifies the entry according to whether or not it may
      89             :   /// generate a relocation entry.  This must be conservative, so if it might
      90             :   /// codegen to a relocatable entry, it should say so.
      91             :   ///
      92             :   /// FIXME: This really should not be in IR.
      93             :   bool needsRelocation() const;
      94             : 
      95             :   /// For aggregates (struct/array/vector) return the constant that corresponds
      96             :   /// to the specified element if possible, or null if not. This can return null
      97             :   /// if the element index is a ConstantExpr, or if 'this' is a constant expr.
      98             :   Constant *getAggregateElement(unsigned Elt) const;
      99             :   Constant *getAggregateElement(Constant *Elt) const;
     100             : 
     101             :   /// If this is a splat vector constant, meaning that all of the elements have
     102             :   /// the same value, return that value. Otherwise return 0.
     103             :   Constant *getSplatValue() const;
     104             : 
     105             :   /// If C is a constant integer then return its value, otherwise C must be a
     106             :   /// vector of constant integers, all equal, and the common value is returned.
     107             :   const APInt &getUniqueInteger() const;
     108             : 
     109             :   /// Called if some element of this constant is no longer valid.
     110             :   /// At this point only other constants may be on the use_list for this
     111             :   /// constant.  Any constants on our Use list must also be destroy'd.  The
     112             :   /// implementation must be sure to remove the constant from the list of
     113             :   /// available cached constants.  Implementations should implement
     114             :   /// destroyConstantImpl to remove constants from any pools/maps they are
     115             :   /// contained it.
     116             :   void destroyConstant();
     117             : 
     118             :   //// Methods for support type inquiry through isa, cast, and dyn_cast:
     119             :   static bool classof(const Value *V) {
     120    16028929 :     return V->getValueID() >= ConstantFirstVal &&
     121     5342954 :            V->getValueID() <= ConstantLastVal;
     122             :   }
     123             : 
     124             :   /// This method is a special form of User::replaceUsesOfWith
     125             :   /// (which does not work on constants) that does work
     126             :   /// on constants.  Basically this method goes through the trouble of building
     127             :   /// a new constant that is equivalent to the current one, with all uses of
     128             :   /// From replaced with uses of To.  After this construction is completed, all
     129             :   /// of the users of 'this' are replaced to use the new constant, and then
     130             :   /// 'this' is deleted.  In general, you should not call this method, instead,
     131             :   /// use Value::replaceAllUsesWith, which automatically dispatches to this
     132             :   /// method as needed.
     133             :   ///
     134             :   void handleOperandChange(Value *, Value *);
     135             : 
     136             :   static Constant *getNullValue(Type* Ty);
     137             : 
     138             :   /// @returns the value for an integer or vector of integer constant of the
     139             :   /// given type that has all its bits set to true.
     140             :   /// @brief Get the all ones value
     141             :   static Constant *getAllOnesValue(Type* Ty);
     142             : 
     143             :   /// Return the value for an integer or pointer constant, or a vector thereof,
     144             :   /// with the given scalar value.
     145             :   static Constant *getIntegerValue(Type *Ty, const APInt &V);
     146             : 
     147             :   /// If there are any dead constant users dangling off of this constant, remove
     148             :   /// them. This method is useful for clients that want to check to see if a
     149             :   /// global is unused, but don't want to deal with potentially dead constants
     150             :   /// hanging off of the globals.
     151             :   void removeDeadConstantUsers() const;
     152             : 
     153             :   const Constant *stripPointerCasts() const {
     154    19597194 :     return cast<Constant>(Value::stripPointerCasts());
     155             :   }
     156             : 
     157             :   Constant *stripPointerCasts() {
     158             :     return const_cast<Constant*>(
     159     9798443 :                       static_cast<const Constant *>(this)->stripPointerCasts());
     160             :   }
     161             : };
     162             : 
     163             : } // end namespace llvm
     164             : 
     165             : #endif // LLVM_IR_CONSTANT_H

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