Check in LLVM r95781.

1 files changed, 234 insertions, 0 deletions

diff --git a/include/llvm/GlobalValue.h b/include/llvm/GlobalValue.h
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+++ b/include/llvm/GlobalValue.h
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+//===-- llvm/GlobalValue.h - Class to represent a global value --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a common base class of all globally definable objects.  As such,
+// it is subclassed by GlobalVariable, GlobalAlias and by Function.  This is
+// used because you can do certain things with these global objects that you
+// can't do to anything else.  For example, use the address of one as a
+// constant.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_GLOBALVALUE_H
+#define LLVM_GLOBALVALUE_H
+
+#include "llvm/Constant.h"
+
+namespace llvm {
+
+class PointerType;
+class Module;
+
+class GlobalValue : public Constant {
+  GlobalValue(const GlobalValue &);             // do not implement
+public:
+  /// @brief An enumeration for the kinds of linkage for global values.
+  enum LinkageTypes {
+    ExternalLinkage = 0,///< Externally visible function
+    AvailableExternallyLinkage, ///< Available for inspection, not emission.
+    LinkOnceAnyLinkage, ///< Keep one copy of function when linking (inline)
+    LinkOnceODRLinkage, ///< Same, but only replaced by something equivalent.
+    WeakAnyLinkage,     ///< Keep one copy of named function when linking (weak)
+    WeakODRLinkage,     ///< Same, but only replaced by something equivalent.
+    AppendingLinkage,   ///< Special purpose, only applies to global arrays
+    InternalLinkage,    ///< Rename collisions when linking (static functions).
+    PrivateLinkage,     ///< Like Internal, but omit from symbol table.
+    LinkerPrivateLinkage, ///< Like Private, but linker removes.
+    DLLImportLinkage,   ///< Function to be imported from DLL
+    DLLExportLinkage,   ///< Function to be accessible from DLL.
+    ExternalWeakLinkage,///< ExternalWeak linkage description.
+    CommonLinkage       ///< Tentative definitions.
+  };
+
+  /// @brief An enumeration for the kinds of visibility of global values.
+  enum VisibilityTypes {
+    DefaultVisibility = 0,  ///< The GV is visible
+    HiddenVisibility,       ///< The GV is hidden
+    ProtectedVisibility     ///< The GV is protected
+  };
+
+protected:
+  GlobalValue(const Type *ty, ValueTy vty, Use *Ops, unsigned NumOps,
+              LinkageTypes linkage, const Twine &Name)
+    : Constant(ty, vty, Ops, NumOps), Parent(0),
+      Linkage(linkage), Visibility(DefaultVisibility), Alignment(0) {
+    setName(Name);
+  }
+
+  Module *Parent;
+  // Note: VC++ treats enums as signed, so an extra bit is required to prevent
+  // Linkage and Visibility from turning into negative values.
+  LinkageTypes Linkage : 5;   // The linkage of this global
+  unsigned Visibility : 2;    // The visibility style of this global
+  unsigned Alignment : 16;    // Alignment of this symbol, must be power of two
+  std::string Section;        // Section to emit this into, empty mean default
+public:
+  ~GlobalValue() {
+    removeDeadConstantUsers();   // remove any dead constants using this.
+  }
+
+  unsigned getAlignment() const { return Alignment; }
+  void setAlignment(unsigned Align) {
+    assert((Align & (Align-1)) == 0 && "Alignment is not a power of 2!");
+    Alignment = Align;
+  }
+
+  VisibilityTypes getVisibility() const { return VisibilityTypes(Visibility); }
+  bool hasDefaultVisibility() const { return Visibility == DefaultVisibility; }
+  bool hasHiddenVisibility() const { return Visibility == HiddenVisibility; }
+  bool hasProtectedVisibility() const {
+    return Visibility == ProtectedVisibility;
+  }
+  void setVisibility(VisibilityTypes V) { Visibility = V; }
+  
+  bool hasSection() const { return !Section.empty(); }
+  const std::string &getSection() const { return Section; }
+  void setSection(StringRef S) { Section = S; }
+  
+  /// If the usage is empty (except transitively dead constants), then this
+  /// global value can be safely deleted since the destructor will
+  /// delete the dead constants as well.
+  /// @brief Determine if the usage of this global value is empty except
+  /// for transitively dead constants.
+  bool use_empty_except_constants();
+
+  /// getType - Global values are always pointers.
+  inline const PointerType *getType() const {
+    return reinterpret_cast<const PointerType*>(User::getType());
+  }
+
+  static LinkageTypes getLinkOnceLinkage(bool ODR) {
+    return ODR ? LinkOnceODRLinkage : LinkOnceAnyLinkage;
+  }
+  static LinkageTypes getWeakLinkage(bool ODR) {
+    return ODR ? WeakODRLinkage : WeakAnyLinkage;
+  }
+
+  bool hasExternalLinkage() const { return Linkage == ExternalLinkage; }
+  bool hasAvailableExternallyLinkage() const {
+    return Linkage == AvailableExternallyLinkage;
+  }
+  bool hasLinkOnceLinkage() const {
+    return Linkage == LinkOnceAnyLinkage || Linkage == LinkOnceODRLinkage;
+  }
+  bool hasWeakLinkage() const {
+    return Linkage == WeakAnyLinkage || Linkage == WeakODRLinkage;
+  }
+  bool hasAppendingLinkage() const { return Linkage == AppendingLinkage; }
+  bool hasInternalLinkage() const { return Linkage == InternalLinkage; }
+  bool hasPrivateLinkage() const { return Linkage == PrivateLinkage; }
+  bool hasLinkerPrivateLinkage() const { return Linkage==LinkerPrivateLinkage; }
+  bool hasLocalLinkage() const {
+    return hasInternalLinkage() || hasPrivateLinkage() ||
+      hasLinkerPrivateLinkage();
+  }
+  bool hasDLLImportLinkage() const { return Linkage == DLLImportLinkage; }
+  bool hasDLLExportLinkage() const { return Linkage == DLLExportLinkage; }
+  bool hasExternalWeakLinkage() const { return Linkage == ExternalWeakLinkage; }
+  bool hasCommonLinkage() const { return Linkage == CommonLinkage; }
+
+  void setLinkage(LinkageTypes LT) { Linkage = LT; }
+  LinkageTypes getLinkage() const { return Linkage; }
+
+  /// mayBeOverridden - Whether the definition of this global may be replaced
+  /// by something non-equivalent at link time.  For example, if a function has
+  /// weak linkage then the code defining it may be replaced by different code.
+  bool mayBeOverridden() const {
+    return (Linkage == WeakAnyLinkage ||
+            Linkage == LinkOnceAnyLinkage ||
+            Linkage == CommonLinkage ||
+            Linkage == ExternalWeakLinkage);
+  }
+
+  /// isWeakForLinker - Whether the definition of this global may be replaced at
+  /// link time.
+  bool isWeakForLinker() const {
+    return (Linkage == AvailableExternallyLinkage ||
+            Linkage == WeakAnyLinkage ||
+            Linkage == WeakODRLinkage ||
+            Linkage == LinkOnceAnyLinkage ||
+            Linkage == LinkOnceODRLinkage ||
+            Linkage == CommonLinkage ||
+            Linkage == ExternalWeakLinkage);
+  }
+
+  /// copyAttributesFrom - copy all additional attributes (those not needed to
+  /// create a GlobalValue) from the GlobalValue Src to this one.
+  virtual void copyAttributesFrom(const GlobalValue *Src);
+
+/// @name Materialization
+/// Materialization is used to construct functions only as they're needed. This
+/// is useful to reduce memory usage in LLVM or parsing work done by the
+/// BitcodeReader to load the Module.
+/// @{
+
+  /// isMaterializable - If this function's Module is being lazily streamed in
+  /// functions from disk or some other source, this method can be used to check
+  /// to see if the function has been read in yet or not.
+  bool isMaterializable() const;
+
+  /// isDematerializable - Returns true if this function was loaded from a
+  /// GVMaterializer that's still attached to its Module and that knows how to
+  /// dematerialize the function.
+  bool isDematerializable() const;
+
+  /// Materialize - make sure this GlobalValue is fully read.  If the module is
+  /// corrupt, this returns true and fills in the optional string with
+  /// information about the problem.  If successful, this returns false.
+  bool Materialize(std::string *ErrInfo = 0);
+
+  /// Dematerialize - If this GlobalValue is read in, and if the GVMaterializer
+  /// supports it, release the memory for the function, and set it up to be
+  /// materialized lazily.  If !isDematerializable(), this method is a noop.
+  void Dematerialize();
+
+/// @}
+
+  /// Override from Constant class. No GlobalValue's are null values so this
+  /// always returns false.
+  virtual bool isNullValue() const { return false; }
+
+  /// Override from Constant class.
+  virtual void destroyConstant();
+
+  /// isDeclaration - Return true if the primary definition of this global 
+  /// value is outside of the current translation unit...
+  virtual bool isDeclaration() const = 0;
+
+  /// removeFromParent - This method unlinks 'this' from the containing module,
+  /// but does not delete it.
+  virtual void removeFromParent() = 0;
+
+  /// eraseFromParent - This method unlinks 'this' from the containing module
+  /// and deletes it.
+  virtual void eraseFromParent() = 0;
+
+  /// getParent - Get the module that this global value is contained inside
+  /// of...
+  inline Module *getParent() { return Parent; }
+  inline const Module *getParent() const { return Parent; }
+
+  /// removeDeadConstantUsers - If there are any dead constant users dangling
+  /// off of this global value, remove them.  This method is useful for clients
+  /// that want to check to see if a global is unused, but don't want to deal
+  /// with potentially dead constants hanging off of the globals.
+  void removeDeadConstantUsers() const;
+
+  // Methods for support type inquiry through isa, cast, and dyn_cast:
+  static inline bool classof(const GlobalValue *) { return true; }
+  static inline bool classof(const Value *V) {
+    return V->getValueID() == Value::FunctionVal ||
+           V->getValueID() == Value::GlobalVariableVal ||
+           V->getValueID() == Value::GlobalAliasVal;
+  }
+};
+
+} // End llvm namespace
+
+#endif