LLVM API Documentation
00001 //===-- Value.cpp - Implement the Value class -----------------------------===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by the LLVM research group and is distributed under 00006 // the University of Illinois Open Source License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 // 00010 // This file implements the Value and User classes. 00011 // 00012 //===----------------------------------------------------------------------===// 00013 00014 #include "llvm/InstrTypes.h" 00015 #include "llvm/SymbolTable.h" 00016 #include "llvm/DerivedTypes.h" 00017 #include "llvm/Constant.h" 00018 #include "llvm/GlobalValue.h" 00019 #include "llvm/Support/LeakDetector.h" 00020 #include <algorithm> 00021 #include <iostream> 00022 using namespace llvm; 00023 00024 //===----------------------------------------------------------------------===// 00025 // Value Class 00026 //===----------------------------------------------------------------------===// 00027 00028 static inline const Type *checkType(const Type *Ty) { 00029 assert(Ty && "Value defined with a null type: Error!"); 00030 return Ty; 00031 } 00032 00033 Value::Value(const Type *ty, unsigned scid, const std::string &name) 00034 : SubclassID(scid), Ty(checkType(ty)), Name(name) { 00035 if (!isa<Constant>(this) && !isa<BasicBlock>(this)) 00036 assert((Ty->isFirstClassType() || Ty == Type::VoidTy || 00037 isa<OpaqueType>(ty)) && 00038 "Cannot create non-first-class values except for constants!"); 00039 if (ty == Type::VoidTy) 00040 assert(name.empty() && "Cannot have named void values!"); 00041 } 00042 00043 Value::~Value() { 00044 #ifndef NDEBUG // Only in -g mode... 00045 // Check to make sure that there are no uses of this value that are still 00046 // around when the value is destroyed. If there are, then we have a dangling 00047 // reference and something is wrong. This code is here to print out what is 00048 // still being referenced. The value in question should be printed as 00049 // a <badref> 00050 // 00051 if (Uses.begin() != Uses.end()) { 00052 std::cerr << "While deleting: " << *Ty << " %" << Name << "\n"; 00053 for (use_const_iterator I = Uses.begin(), E = Uses.end(); I != E; ++I) 00054 std::cerr << "Use still stuck around after Def is destroyed:" 00055 << **I << "\n"; 00056 } 00057 #endif 00058 assert(Uses.begin() == Uses.end() &&"Uses remain when a value is destroyed!"); 00059 00060 // There should be no uses of this object anymore, remove it. 00061 LeakDetector::removeGarbageObject(this); 00062 } 00063 00064 00065 // uncheckedReplaceAllUsesWith - This is exactly the same as replaceAllUsesWith, 00066 // except that it doesn't have all of the asserts. The asserts fail because we 00067 // are half-way done resolving types, which causes some types to exist as two 00068 // different Type*'s at the same time. This is a sledgehammer to work around 00069 // this problem. 00070 // 00071 void Value::uncheckedReplaceAllUsesWith(Value *New) { 00072 while (!Uses.empty()) { 00073 Use &U = Uses.back(); 00074 // Must handle Constants specially, we cannot call replaceUsesOfWith on a 00075 // constant! 00076 if (Constant *C = dyn_cast<Constant>(U.getUser())) { 00077 if (!isa<GlobalValue>(C)) 00078 C->replaceUsesOfWithOnConstant(this, New, true); 00079 else 00080 U.set(New); 00081 } else { 00082 U.set(New); 00083 } 00084 } 00085 } 00086 00087 void Value::replaceAllUsesWith(Value *New) { 00088 assert(New && "Value::replaceAllUsesWith(<null>) is invalid!"); 00089 assert(New != this && "this->replaceAllUsesWith(this) is NOT valid!"); 00090 assert(New->getType() == getType() && 00091 "replaceAllUses of value with new value of different type!"); 00092 00093 uncheckedReplaceAllUsesWith(New); 00094 } 00095 00096 //===----------------------------------------------------------------------===// 00097 // User Class 00098 //===----------------------------------------------------------------------===// 00099 00100 // replaceUsesOfWith - Replaces all references to the "From" definition with 00101 // references to the "To" definition. 00102 // 00103 void User::replaceUsesOfWith(Value *From, Value *To) { 00104 if (From == To) return; // Duh what? 00105 00106 assert(!isa<Constant>(this) || isa<GlobalValue>(this) && 00107 "Cannot call User::replaceUsesofWith on a constant!"); 00108 00109 for (unsigned i = 0, E = getNumOperands(); i != E; ++i) 00110 if (getOperand(i) == From) { // Is This operand is pointing to oldval? 00111 // The side effects of this setOperand call include linking to 00112 // "To", adding "this" to the uses list of To, and 00113 // most importantly, removing "this" from the use list of "From". 00114 setOperand(i, To); // Fix it now... 00115 } 00116 } 00117