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      1 //===-- Module.cpp - Implement the Module class ---------------------------===//
      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 implements the Module class for the IR library.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "llvm/IR/Module.h"
     15 #include "SymbolTableListTraitsImpl.h"
     16 #include "llvm/ADT/DenseSet.h"
     17 #include "llvm/ADT/STLExtras.h"
     18 #include "llvm/ADT/SmallString.h"
     19 #include "llvm/ADT/StringExtras.h"
     20 #include "llvm/GVMaterializer.h"
     21 #include "llvm/IR/Constants.h"
     22 #include "llvm/IR/DerivedTypes.h"
     23 #include "llvm/IR/InstrTypes.h"
     24 #include "llvm/IR/LLVMContext.h"
     25 #include "llvm/Support/LeakDetector.h"
     26 #include <algorithm>
     27 #include <cstdarg>
     28 #include <cstdlib>
     29 using namespace llvm;
     30 
     31 //===----------------------------------------------------------------------===//
     32 // Methods to implement the globals and functions lists.
     33 //
     34 
     35 // Explicit instantiations of SymbolTableListTraits since some of the methods
     36 // are not in the public header file.
     37 template class llvm::SymbolTableListTraits<Function, Module>;
     38 template class llvm::SymbolTableListTraits<GlobalVariable, Module>;
     39 template class llvm::SymbolTableListTraits<GlobalAlias, Module>;
     40 
     41 //===----------------------------------------------------------------------===//
     42 // Primitive Module methods.
     43 //
     44 
     45 Module::Module(StringRef MID, LLVMContext& C)
     46   : Context(C), Materializer(NULL), ModuleID(MID) {
     47   ValSymTab = new ValueSymbolTable();
     48   NamedMDSymTab = new StringMap<NamedMDNode *>();
     49   Context.addModule(this);
     50 }
     51 
     52 Module::~Module() {
     53   Context.removeModule(this);
     54   dropAllReferences();
     55   GlobalList.clear();
     56   FunctionList.clear();
     57   AliasList.clear();
     58   NamedMDList.clear();
     59   delete ValSymTab;
     60   delete static_cast<StringMap<NamedMDNode *> *>(NamedMDSymTab);
     61 }
     62 
     63 /// Target endian information.
     64 Module::Endianness Module::getEndianness() const {
     65   StringRef temp = DataLayout;
     66   Module::Endianness ret = AnyEndianness;
     67 
     68   while (!temp.empty()) {
     69     std::pair<StringRef, StringRef> P = getToken(temp, "-");
     70 
     71     StringRef token = P.first;
     72     temp = P.second;
     73 
     74     if (token[0] == 'e') {
     75       ret = LittleEndian;
     76     } else if (token[0] == 'E') {
     77       ret = BigEndian;
     78     }
     79   }
     80 
     81   return ret;
     82 }
     83 
     84 /// Target Pointer Size information.
     85 Module::PointerSize Module::getPointerSize() const {
     86   StringRef temp = DataLayout;
     87   Module::PointerSize ret = AnyPointerSize;
     88 
     89   while (!temp.empty()) {
     90     std::pair<StringRef, StringRef> TmpP = getToken(temp, "-");
     91     temp = TmpP.second;
     92     TmpP = getToken(TmpP.first, ":");
     93     StringRef token = TmpP.second, signalToken = TmpP.first;
     94 
     95     if (signalToken[0] == 'p') {
     96       int size = 0;
     97       getToken(token, ":").first.getAsInteger(10, size);
     98       if (size == 32)
     99         ret = Pointer32;
    100       else if (size == 64)
    101         ret = Pointer64;
    102     }
    103   }
    104 
    105   return ret;
    106 }
    107 
    108 /// getNamedValue - Return the first global value in the module with
    109 /// the specified name, of arbitrary type.  This method returns null
    110 /// if a global with the specified name is not found.
    111 GlobalValue *Module::getNamedValue(StringRef Name) const {
    112   return cast_or_null<GlobalValue>(getValueSymbolTable().lookup(Name));
    113 }
    114 
    115 /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
    116 /// This ID is uniqued across modules in the current LLVMContext.
    117 unsigned Module::getMDKindID(StringRef Name) const {
    118   return Context.getMDKindID(Name);
    119 }
    120 
    121 /// getMDKindNames - Populate client supplied SmallVector with the name for
    122 /// custom metadata IDs registered in this LLVMContext.   ID #0 is not used,
    123 /// so it is filled in as an empty string.
    124 void Module::getMDKindNames(SmallVectorImpl<StringRef> &Result) const {
    125   return Context.getMDKindNames(Result);
    126 }
    127 
    128 
    129 //===----------------------------------------------------------------------===//
    130 // Methods for easy access to the functions in the module.
    131 //
    132 
    133 // getOrInsertFunction - Look up the specified function in the module symbol
    134 // table.  If it does not exist, add a prototype for the function and return
    135 // it.  This is nice because it allows most passes to get away with not handling
    136 // the symbol table directly for this common task.
    137 //
    138 Constant *Module::getOrInsertFunction(StringRef Name,
    139                                       FunctionType *Ty,
    140                                       AttributeSet AttributeList) {
    141   // See if we have a definition for the specified function already.
    142   GlobalValue *F = getNamedValue(Name);
    143   if (F == 0) {
    144     // Nope, add it
    145     Function *New = Function::Create(Ty, GlobalVariable::ExternalLinkage, Name);
    146     if (!New->isIntrinsic())       // Intrinsics get attrs set on construction
    147       New->setAttributes(AttributeList);
    148     FunctionList.push_back(New);
    149     return New;                    // Return the new prototype.
    150   }
    151 
    152   // Okay, the function exists.  Does it have externally visible linkage?
    153   if (F->hasLocalLinkage()) {
    154     // Clear the function's name.
    155     F->setName("");
    156     // Retry, now there won't be a conflict.
    157     Constant *NewF = getOrInsertFunction(Name, Ty);
    158     F->setName(Name);
    159     return NewF;
    160   }
    161 
    162   // If the function exists but has the wrong type, return a bitcast to the
    163   // right type.
    164   if (F->getType() != PointerType::getUnqual(Ty))
    165     return ConstantExpr::getBitCast(F, PointerType::getUnqual(Ty));
    166 
    167   // Otherwise, we just found the existing function or a prototype.
    168   return F;
    169 }
    170 
    171 Constant *Module::getOrInsertTargetIntrinsic(StringRef Name,
    172                                              FunctionType *Ty,
    173                                              AttributeSet AttributeList) {
    174   // See if we have a definition for the specified function already.
    175   GlobalValue *F = getNamedValue(Name);
    176   if (F == 0) {
    177     // Nope, add it
    178     Function *New = Function::Create(Ty, GlobalVariable::ExternalLinkage, Name);
    179     New->setAttributes(AttributeList);
    180     FunctionList.push_back(New);
    181     return New; // Return the new prototype.
    182   }
    183 
    184   // Otherwise, we just found the existing function or a prototype.
    185   return F;
    186 }
    187 
    188 Constant *Module::getOrInsertFunction(StringRef Name,
    189                                       FunctionType *Ty) {
    190   return getOrInsertFunction(Name, Ty, AttributeSet());
    191 }
    192 
    193 // getOrInsertFunction - Look up the specified function in the module symbol
    194 // table.  If it does not exist, add a prototype for the function and return it.
    195 // This version of the method takes a null terminated list of function
    196 // arguments, which makes it easier for clients to use.
    197 //
    198 Constant *Module::getOrInsertFunction(StringRef Name,
    199                                       AttributeSet AttributeList,
    200                                       Type *RetTy, ...) {
    201   va_list Args;
    202   va_start(Args, RetTy);
    203 
    204   // Build the list of argument types...
    205   std::vector<Type*> ArgTys;
    206   while (Type *ArgTy = va_arg(Args, Type*))
    207     ArgTys.push_back(ArgTy);
    208 
    209   va_end(Args);
    210 
    211   // Build the function type and chain to the other getOrInsertFunction...
    212   return getOrInsertFunction(Name,
    213                              FunctionType::get(RetTy, ArgTys, false),
    214                              AttributeList);
    215 }
    216 
    217 Constant *Module::getOrInsertFunction(StringRef Name,
    218                                       Type *RetTy, ...) {
    219   va_list Args;
    220   va_start(Args, RetTy);
    221 
    222   // Build the list of argument types...
    223   std::vector<Type*> ArgTys;
    224   while (Type *ArgTy = va_arg(Args, Type*))
    225     ArgTys.push_back(ArgTy);
    226 
    227   va_end(Args);
    228 
    229   // Build the function type and chain to the other getOrInsertFunction...
    230   return getOrInsertFunction(Name,
    231                              FunctionType::get(RetTy, ArgTys, false),
    232                              AttributeSet());
    233 }
    234 
    235 // getFunction - Look up the specified function in the module symbol table.
    236 // If it does not exist, return null.
    237 //
    238 Function *Module::getFunction(StringRef Name) const {
    239   return dyn_cast_or_null<Function>(getNamedValue(Name));
    240 }
    241 
    242 //===----------------------------------------------------------------------===//
    243 // Methods for easy access to the global variables in the module.
    244 //
    245 
    246 /// getGlobalVariable - Look up the specified global variable in the module
    247 /// symbol table.  If it does not exist, return null.  The type argument
    248 /// should be the underlying type of the global, i.e., it should not have
    249 /// the top-level PointerType, which represents the address of the global.
    250 /// If AllowLocal is set to true, this function will return types that
    251 /// have an local. By default, these types are not returned.
    252 ///
    253 GlobalVariable *Module::getGlobalVariable(StringRef Name,
    254                                           bool AllowLocal) const {
    255   if (GlobalVariable *Result =
    256       dyn_cast_or_null<GlobalVariable>(getNamedValue(Name)))
    257     if (AllowLocal || !Result->hasLocalLinkage())
    258       return Result;
    259   return 0;
    260 }
    261 
    262 /// getOrInsertGlobal - Look up the specified global in the module symbol table.
    263 ///   1. If it does not exist, add a declaration of the global and return it.
    264 ///   2. Else, the global exists but has the wrong type: return the function
    265 ///      with a constantexpr cast to the right type.
    266 ///   3. Finally, if the existing global is the correct delclaration, return the
    267 ///      existing global.
    268 Constant *Module::getOrInsertGlobal(StringRef Name, Type *Ty) {
    269   // See if we have a definition for the specified global already.
    270   GlobalVariable *GV = dyn_cast_or_null<GlobalVariable>(getNamedValue(Name));
    271   if (GV == 0) {
    272     // Nope, add it
    273     GlobalVariable *New =
    274       new GlobalVariable(*this, Ty, false, GlobalVariable::ExternalLinkage,
    275                          0, Name);
    276      return New;                    // Return the new declaration.
    277   }
    278 
    279   // If the variable exists but has the wrong type, return a bitcast to the
    280   // right type.
    281   if (GV->getType() != PointerType::getUnqual(Ty))
    282     return ConstantExpr::getBitCast(GV, PointerType::getUnqual(Ty));
    283 
    284   // Otherwise, we just found the existing function or a prototype.
    285   return GV;
    286 }
    287 
    288 //===----------------------------------------------------------------------===//
    289 // Methods for easy access to the global variables in the module.
    290 //
    291 
    292 // getNamedAlias - Look up the specified global in the module symbol table.
    293 // If it does not exist, return null.
    294 //
    295 GlobalAlias *Module::getNamedAlias(StringRef Name) const {
    296   return dyn_cast_or_null<GlobalAlias>(getNamedValue(Name));
    297 }
    298 
    299 /// getNamedMetadata - Return the first NamedMDNode in the module with the
    300 /// specified name. This method returns null if a NamedMDNode with the
    301 /// specified name is not found.
    302 NamedMDNode *Module::getNamedMetadata(const Twine &Name) const {
    303   SmallString<256> NameData;
    304   StringRef NameRef = Name.toStringRef(NameData);
    305   return static_cast<StringMap<NamedMDNode*> *>(NamedMDSymTab)->lookup(NameRef);
    306 }
    307 
    308 /// getOrInsertNamedMetadata - Return the first named MDNode in the module
    309 /// with the specified name. This method returns a new NamedMDNode if a
    310 /// NamedMDNode with the specified name is not found.
    311 NamedMDNode *Module::getOrInsertNamedMetadata(StringRef Name) {
    312   NamedMDNode *&NMD =
    313     (*static_cast<StringMap<NamedMDNode *> *>(NamedMDSymTab))[Name];
    314   if (!NMD) {
    315     NMD = new NamedMDNode(Name);
    316     NMD->setParent(this);
    317     NamedMDList.push_back(NMD);
    318   }
    319   return NMD;
    320 }
    321 
    322 /// eraseNamedMetadata - Remove the given NamedMDNode from this module and
    323 /// delete it.
    324 void Module::eraseNamedMetadata(NamedMDNode *NMD) {
    325   static_cast<StringMap<NamedMDNode *> *>(NamedMDSymTab)->erase(NMD->getName());
    326   NamedMDList.erase(NMD);
    327 }
    328 
    329 /// getModuleFlagsMetadata - Returns the module flags in the provided vector.
    330 void Module::
    331 getModuleFlagsMetadata(SmallVectorImpl<ModuleFlagEntry> &Flags) const {
    332   const NamedMDNode *ModFlags = getModuleFlagsMetadata();
    333   if (!ModFlags) return;
    334 
    335   for (unsigned i = 0, e = ModFlags->getNumOperands(); i != e; ++i) {
    336     MDNode *Flag = ModFlags->getOperand(i);
    337     ConstantInt *Behavior = cast<ConstantInt>(Flag->getOperand(0));
    338     MDString *Key = cast<MDString>(Flag->getOperand(1));
    339     Value *Val = Flag->getOperand(2);
    340     Flags.push_back(ModuleFlagEntry(ModFlagBehavior(Behavior->getZExtValue()),
    341                                     Key, Val));
    342   }
    343 }
    344 
    345 /// getModuleFlagsMetadata - Returns the NamedMDNode in the module that
    346 /// represents module-level flags. This method returns null if there are no
    347 /// module-level flags.
    348 NamedMDNode *Module::getModuleFlagsMetadata() const {
    349   return getNamedMetadata("llvm.module.flags");
    350 }
    351 
    352 /// getOrInsertModuleFlagsMetadata - Returns the NamedMDNode in the module that
    353 /// represents module-level flags. If module-level flags aren't found, it
    354 /// creates the named metadata that contains them.
    355 NamedMDNode *Module::getOrInsertModuleFlagsMetadata() {
    356   return getOrInsertNamedMetadata("llvm.module.flags");
    357 }
    358 
    359 /// addModuleFlag - Add a module-level flag to the module-level flags
    360 /// metadata. It will create the module-level flags named metadata if it doesn't
    361 /// already exist.
    362 void Module::addModuleFlag(ModFlagBehavior Behavior, StringRef Key,
    363                            Value *Val) {
    364   Type *Int32Ty = Type::getInt32Ty(Context);
    365   Value *Ops[3] = {
    366     ConstantInt::get(Int32Ty, Behavior), MDString::get(Context, Key), Val
    367   };
    368   getOrInsertModuleFlagsMetadata()->addOperand(MDNode::get(Context, Ops));
    369 }
    370 void Module::addModuleFlag(ModFlagBehavior Behavior, StringRef Key,
    371                            uint32_t Val) {
    372   Type *Int32Ty = Type::getInt32Ty(Context);
    373   addModuleFlag(Behavior, Key, ConstantInt::get(Int32Ty, Val));
    374 }
    375 void Module::addModuleFlag(MDNode *Node) {
    376   assert(Node->getNumOperands() == 3 &&
    377          "Invalid number of operands for module flag!");
    378   assert(isa<ConstantInt>(Node->getOperand(0)) &&
    379          isa<MDString>(Node->getOperand(1)) &&
    380          "Invalid operand types for module flag!");
    381   getOrInsertModuleFlagsMetadata()->addOperand(Node);
    382 }
    383 
    384 //===----------------------------------------------------------------------===//
    385 // Methods to control the materialization of GlobalValues in the Module.
    386 //
    387 void Module::setMaterializer(GVMaterializer *GVM) {
    388   assert(!Materializer &&
    389          "Module already has a GVMaterializer.  Call MaterializeAllPermanently"
    390          " to clear it out before setting another one.");
    391   Materializer.reset(GVM);
    392 }
    393 
    394 bool Module::isMaterializable(const GlobalValue *GV) const {
    395   if (Materializer)
    396     return Materializer->isMaterializable(GV);
    397   return false;
    398 }
    399 
    400 bool Module::isDematerializable(const GlobalValue *GV) const {
    401   if (Materializer)
    402     return Materializer->isDematerializable(GV);
    403   return false;
    404 }
    405 
    406 bool Module::Materialize(GlobalValue *GV, std::string *ErrInfo) {
    407   if (Materializer)
    408     return Materializer->Materialize(GV, ErrInfo);
    409   return false;
    410 }
    411 
    412 void Module::Dematerialize(GlobalValue *GV) {
    413   if (Materializer)
    414     return Materializer->Dematerialize(GV);
    415 }
    416 
    417 bool Module::MaterializeAll(std::string *ErrInfo) {
    418   if (!Materializer)
    419     return false;
    420   return Materializer->MaterializeModule(this, ErrInfo);
    421 }
    422 
    423 bool Module::MaterializeAllPermanently(std::string *ErrInfo) {
    424   if (MaterializeAll(ErrInfo))
    425     return true;
    426   Materializer.reset();
    427   return false;
    428 }
    429 
    430 //===----------------------------------------------------------------------===//
    431 // Other module related stuff.
    432 //
    433 
    434 
    435 // dropAllReferences() - This function causes all the subelements to "let go"
    436 // of all references that they are maintaining.  This allows one to 'delete' a
    437 // whole module at a time, even though there may be circular references... first
    438 // all references are dropped, and all use counts go to zero.  Then everything
    439 // is deleted for real.  Note that no operations are valid on an object that
    440 // has "dropped all references", except operator delete.
    441 //
    442 void Module::dropAllReferences() {
    443   for(Module::iterator I = begin(), E = end(); I != E; ++I)
    444     I->dropAllReferences();
    445 
    446   for(Module::global_iterator I = global_begin(), E = global_end(); I != E; ++I)
    447     I->dropAllReferences();
    448 
    449   for(Module::alias_iterator I = alias_begin(), E = alias_end(); I != E; ++I)
    450     I->dropAllReferences();
    451 }
    452