Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/IR/Constant.h
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//===-- llvm/Constant.h - Constant class definition -------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the declaration of the Constant class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_IR_CONSTANT_H
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#define LLVM_IR_CONSTANT_H
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#include "llvm/IR/User.h"
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#include "llvm/IR/Value.h"
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#include "llvm/Support/Casting.h"
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namespace llvm {
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class APInt;
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/// This is an important base class in LLVM. It provides the common facilities
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/// of all constant values in an LLVM program. A constant is a value that is
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/// immutable at runtime. Functions are constants because their address is
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/// immutable. Same with global variables.
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///
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/// All constants share the capabilities provided in this class. All constants
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/// can have a null value. They can have an operand list. Constants can be
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/// simple (integer and floating point values), complex (arrays and structures),
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/// or expression based (computations yielding a constant value composed of
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/// only certain operators and other constant values).
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///
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/// Note that Constants are immutable (once created they never change)
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/// and are fully shared by structural equivalence.  This means that two
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/// structurally equivalent constants will always have the same address.
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/// Constants are created on demand as needed and never deleted: thus clients
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/// don't have to worry about the lifetime of the objects.
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/// LLVM Constant Representation
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class Constant : public User {
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protected:
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  Constant(Type *ty, ValueTy vty, Use *Ops, unsigned NumOps)
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    : User(ty, vty, Ops, NumOps) {}
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public:
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  void operator=(const Constant &) = delete;
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  Constant(const Constant &) = delete;
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  /// Return true if this is the value that would be returned by getNullValue.
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  bool isNullValue() const;
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  /// Returns true if the value is one.
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  bool isOneValue() const;
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  /// Return true if this is the value that would be returned by
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  /// getAllOnesValue.
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  bool isAllOnesValue() const;
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  /// Return true if the value is what would be returned by
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  /// getZeroValueForNegation.
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  bool isNegativeZeroValue() const;
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  /// Return true if the value is negative zero or null value.
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  bool isZeroValue() const;
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  /// Return true if the value is not the smallest signed value.
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  bool isNotMinSignedValue() const;
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  /// Return true if the value is the smallest signed value.
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  bool isMinSignedValue() const;
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  /// Return true if this is a finite and non-zero floating-point scalar
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  /// constant or a vector constant with all finite and non-zero elements.
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  bool isFiniteNonZeroFP() const;
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  /// Return true if this is a normal (as opposed to denormal) floating-point
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  /// scalar constant or a vector constant with all normal elements.
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  bool isNormalFP() const;
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  /// Return true if this scalar has an exact multiplicative inverse or this
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  /// vector has an exact multiplicative inverse for each element in the vector.
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  bool hasExactInverseFP() const;
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  /// Return true if this is a floating-point NaN constant or a vector
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  /// floating-point constant with all NaN elements.
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  bool isNaN() const;
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  /// Return true if this is a vector constant that includes any undefined
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  /// elements.
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  bool containsUndefElement() const;
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  /// Return true if this is a vector constant that includes any constant
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  /// expressions.
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  bool containsConstantExpression() const;
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  /// Return true if evaluation of this constant could trap. This is true for
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  /// things like constant expressions that could divide by zero.
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  bool canTrap() const;
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  /// Return true if the value can vary between threads.
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  bool isThreadDependent() const;
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  /// Return true if the value is dependent on a dllimport variable.
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  bool isDLLImportDependent() const;
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  /// Return true if the constant has users other than constant expressions and
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  /// other dangling things.
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  bool isConstantUsed() const;
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  /// This method classifies the entry according to whether or not it may
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  /// generate a relocation entry.  This must be conservative, so if it might
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  /// codegen to a relocatable entry, it should say so.
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  ///
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  /// FIXME: This really should not be in IR.
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  bool needsRelocation() const;
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  /// For aggregates (struct/array/vector) return the constant that corresponds
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  /// to the specified element if possible, or null if not. This can return null
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  /// if the element index is a ConstantExpr, if 'this' is a constant expr or
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  /// if the constant does not fit into an uint64_t.
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  Constant *getAggregateElement(unsigned Elt) const;
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  Constant *getAggregateElement(Constant *Elt) const;
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  /// If this is a splat vector constant, meaning that all of the elements have
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  /// the same value, return that value. Otherwise return 0.
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  Constant *getSplatValue() const;
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  /// If C is a constant integer then return its value, otherwise C must be a
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  /// vector of constant integers, all equal, and the common value is returned.
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  const APInt &getUniqueInteger() const;
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  /// Called if some element of this constant is no longer valid.
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  /// At this point only other constants may be on the use_list for this
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  /// constant.  Any constants on our Use list must also be destroy'd.  The
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  /// implementation must be sure to remove the constant from the list of
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  /// available cached constants.  Implementations should implement
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  /// destroyConstantImpl to remove constants from any pools/maps they are
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  /// contained it.
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  void destroyConstant();
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  //// Methods for support type inquiry through isa, cast, and dyn_cast:
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  static bool classof(const Value *V) {
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    static_assert(ConstantFirstVal == 0, "V->getValueID() >= ConstantFirstVal always succeeds");
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    return V->getValueID() <= ConstantLastVal;
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  }
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  /// This method is a special form of User::replaceUsesOfWith
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  /// (which does not work on constants) that does work
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  /// on constants.  Basically this method goes through the trouble of building
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  /// a new constant that is equivalent to the current one, with all uses of
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  /// From replaced with uses of To.  After this construction is completed, all
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  /// of the users of 'this' are replaced to use the new constant, and then
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  /// 'this' is deleted.  In general, you should not call this method, instead,
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  /// use Value::replaceAllUsesWith, which automatically dispatches to this
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  /// method as needed.
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  ///
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  void handleOperandChange(Value *, Value *);
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  static Constant *getNullValue(Type* Ty);
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  /// @returns the value for an integer or vector of integer constant of the
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  /// given type that has all its bits set to true.
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  /// Get the all ones value
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  static Constant *getAllOnesValue(Type* Ty);
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  /// Return the value for an integer or pointer constant, or a vector thereof,
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  /// with the given scalar value.
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  static Constant *getIntegerValue(Type *Ty, const APInt &V);
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  /// If there are any dead constant users dangling off of this constant, remove
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  /// them. This method is useful for clients that want to check to see if a
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  /// global is unused, but don't want to deal with potentially dead constants
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  /// hanging off of the globals.
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  void removeDeadConstantUsers() const;
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  const Constant *stripPointerCasts() const {
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    return cast<Constant>(Value::stripPointerCasts());
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  }
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  Constant *stripPointerCasts() {
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    return const_cast<Constant*>(
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                      static_cast<const Constant *>(this)->stripPointerCasts());
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  }
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};
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} // end namespace llvm
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#endif // LLVM_IR_CONSTANT_H