Subzero. Allocate global initializers from a dedicated arena.

src/IceConverter.cpp

 //===- subzero/src/IceConverter.cpp - Converts LLVM to Ice  ---------------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 641 matching lines @@
 //
 // Note: this currently assumes that the given IR was verified to be valid
 // PNaCl bitcode. Otherwise, the behavior is undefined.
 class LLVM2ICEGlobalsConverter : public LLVM2ICEConverter {
   LLVM2ICEGlobalsConverter() = delete;
   LLVM2ICEGlobalsConverter(const LLVM2ICEGlobalsConverter &) = delete;
   LLVM2ICEGlobalsConverter &
   operator=(const LLVM2ICEGlobalsConverter &) = delete;
 
 public:
-  explicit LLVM2ICEGlobalsConverter(Ice::Converter &Converter)
-      : LLVM2ICEConverter(Converter) {}
+  explicit LLVM2ICEGlobalsConverter(Ice::Converter &Converter,
+                                    Ice::VariableDeclarationList *G)
+      : LLVM2ICEConverter(Converter), GlobalPool(G) {}
 
   /// Converts global variables, and their initializers into ICE global variable
   /// declarations, for module Mod. Returns the set of converted declarations.
-  std::unique_ptr<Ice::VariableDeclarationList>
-  convertGlobalsToIce(Module *Mod);
+  void convertGlobalsToIce(Module *Mod);
 
 private:
   // Adds the Initializer to the list of initializers for the Global variable
   // declaration.
   void addGlobalInitializer(Ice::VariableDeclaration &Global,
                             const Constant *Initializer) {
     constexpr bool HasOffset = false;
     constexpr Ice::RelocOffsetT Offset = 0;
     addGlobalInitializer(Global, Initializer, HasOffset, Offset);
   }
@@ skipping 11 matching lines @@
     const auto CI = dyn_cast<ConstantInt>(C);
     if (CI && CI->getType()->isIntegerTy(32))
       return CI->getSExtValue();
 
     std::string Buffer;
     raw_string_ostream StrBuf(Buffer);
     StrBuf << "Constant not i32 literal: " << *C;
     report_fatal_error(StrBuf.str());
     return 0;
   }
+
+  Ice::VariableDeclarationList *GlobalPool;
 };
 
-std::unique_ptr<Ice::VariableDeclarationList>
-LLVM2ICEGlobalsConverter::convertGlobalsToIce(Module *Mod) {
-  std::unique_ptr<Ice::VariableDeclarationList> VariableDeclarations(
-      new Ice::VariableDeclarationList);
+void LLVM2ICEGlobalsConverter::convertGlobalsToIce(Module *Mod) {
   for (Module::const_global_iterator I = Mod->global_begin(),
                                      E = Mod->global_end();
        I != E; ++I) {
 
     const GlobalVariable *GV = I;
 
     Ice::GlobalDeclaration *Var = getConverter().getGlobalDeclaration(GV);
     auto *VarDecl = cast<Ice::VariableDeclaration>(Var);
-    VariableDeclarations->push_back(VarDecl);
+    GlobalPool->push_back(VarDecl);
 
     if (!GV->hasInternalLinkage() && GV->hasInitializer()) {
       std::string Buffer;
       raw_string_ostream StrBuf(Buffer);
       StrBuf << "Can't define external global declaration: " << GV->getName();
       report_fatal_error(StrBuf.str());
     }
 
     if (!GV->hasInitializer()) {
       if (Ctx->getFlags().getAllowUninitializedGlobals())
@@ skipping 12 matching lines @@
                                              E = CompoundInit->op_end();
            I != E; ++I) {
         if (const auto Init = dyn_cast<Constant>(I)) {
           addGlobalInitializer(*VarDecl, Init);
         }
       }
     } else {
       addGlobalInitializer(*VarDecl, Initializer);
     }
   }
-  return VariableDeclarations;
 }
 
 void LLVM2ICEGlobalsConverter::addGlobalInitializer(
     Ice::VariableDeclaration &Global, const Constant *Initializer,
     bool HasOffset, Ice::RelocOffsetT Offset) {
   (void)HasOffset;
   assert(HasOffset || Offset == 0);
 
   if (const auto CDA = dyn_cast<ConstantDataArray>(Initializer)) {
     assert(!HasOffset && isa<IntegerType>(CDA->getElementType()) &&
            (cast<IntegerType>(CDA->getElementType())->getBitWidth() == 8));
     Global.addInitializer(Ice::VariableDeclaration::DataInitializer::create(
-        CDA->getRawDataValues().data(), CDA->getNumElements()));
+        GlobalPool, CDA->getRawDataValues().data(), CDA->getNumElements()));
     return;
   }
 
   if (isa<ConstantAggregateZero>(Initializer)) {
     if (const auto AT = dyn_cast<ArrayType>(Initializer->getType())) {
       assert(!HasOffset && isa<IntegerType>(AT->getElementType()) &&
              (cast<IntegerType>(AT->getElementType())->getBitWidth() == 8));
       Global.addInitializer(Ice::VariableDeclaration::ZeroInitializer::create(
-          AT->getNumElements()));
+          GlobalPool, AT->getNumElements()));
     } else {
       llvm_unreachable("Unhandled constant aggregate zero type");
     }
     return;
   }
 
   if (const auto Exp = dyn_cast<ConstantExpr>(Initializer)) {
     switch (Exp->getOpcode()) {
     case Instruction::Add:
       assert(!HasOffset);
       addGlobalInitializer(Global, Exp->getOperand(0), true,
                            getIntegerLiteralConstant(Exp->getOperand(1)));
       return;
     case Instruction::PtrToInt: {
       assert(TypeConverter.convertToIceType(Exp->getType()) ==
              Ice::getPointerType());
       const auto GV = dyn_cast<GlobalValue>(Exp->getOperand(0));
       assert(GV);
       const Ice::GlobalDeclaration *Addr =
           getConverter().getGlobalDeclaration(GV);
       Global.addInitializer(Ice::VariableDeclaration::RelocInitializer::create(
-          Addr, {Ice::RelocOffset::create(Ctx, Offset)}));
+          GlobalPool, Addr, {Ice::RelocOffset::create(Ctx, Offset)}));
       return;
     }
     default:
       break;
     }
   }
 
   std::string Buffer;
   raw_string_ostream StrBuf(Buffer);
   StrBuf << "Unhandled global initializer: " << Initializer;
@@ skipping 81 matching lines @@
     if (!IceFunc->validateTypeSignature(Ctx))
       report_fatal_error(IceFunc->getTypeSignatureError(Ctx));
     GlobalDeclarationMap[&Func] = IceFunc;
   }
   // Install global variable declarations.
   for (Module::const_global_iterator I = Mod->global_begin(),
                                      E = Mod->global_end();
        I != E; ++I) {
     const GlobalVariable *GV = I;
     constexpr bool NoSuppressMangling = false;
-    auto *Var =
-        VariableDeclaration::create(Ctx, NoSuppressMangling, GV->getLinkage());
+    auto *Var = VariableDeclaration::create(
+        GlobalDeclarationsPool.get(), NoSuppressMangling, GV->getLinkage());
     Var->setAlignment(GV->getAlignment());
     Var->setIsConstant(GV->isConstant());
     Var->setName(GV->getName());
     if (!Var->verifyLinkageCorrect(Ctx)) {
       std::string Buffer;
       raw_string_ostream StrBuf(Buffer);
       StrBuf << "Global " << Var->getName()
              << " has incorrect linkage: " << Var->getLinkageName();
       if (Var->isExternal())
         StrBuf << "\n  Use flag -allow-externally-defined-symbols to override";
       report_fatal_error(StrBuf.str());
     }
     GlobalDeclarationMap[GV] = Var;
   }
 }
 
 void Converter::convertGlobals(Module *Mod) {
-  lowerGlobals(LLVM2ICEGlobalsConverter(*this).convertGlobalsToIce(Mod));
+  LLVM2ICEGlobalsConverter(*this, GlobalDeclarationsPool.get())
+      .convertGlobalsToIce(Mod);
+  lowerGlobals(std::move(GlobalDeclarationsPool));
 }
 
 void Converter::convertFunctions() {
   const TimerStackIdT StackID = GlobalContext::TSK_Funcs;
   for (const Function &I : *Mod) {
     if (I.empty())
       continue;
 
     TimerIdT TimerID = 0;
     const bool TimeThisFunction = Ctx->getFlags().getTimeEachFunction();
     if (TimeThisFunction) {
       TimerID = Ctx->getTimerID(StackID, I.getName());
       Ctx->pushTimer(TimerID, StackID);
     }
     LLVM2ICEFunctionConverter FunctionConverter(*this);
     FunctionConverter.convertFunction(&I);
     if (TimeThisFunction)
       Ctx->popTimer(TimerID, StackID);
   }
 }
 
 } // end of namespace Ice