CodeGenModule.cpp

//===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This coordinates the per-module state used while generating code.
//
//===----------------------------------------------------------------------===//

#include "CGDebugInfo.h"
#include "CodeGenModule.h"
#include "CodeGenFunction.h"
#include "CGCall.h"
#include "CGObjCRuntime.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/CallingConv.h"
#include "llvm/Module.h"
#include "llvm/Intrinsics.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Analysis/Verifier.h"
using namespace clang;
using namespace CodeGen;


CodeGenModule::CodeGenModule(ASTContext &C, const LangOptions &LO,
                             llvm::Module &M, const llvm::TargetData &TD,
                             Diagnostic &diags, bool GenerateDebugInfo)
  : Context(C), Features(LO), TheModule(M), TheTargetData(TD), Diags(diags),
    Types(C, M, TD), Runtime(0), MemCpyFn(0), MemMoveFn(0), MemSetFn(0),
    CFConstantStringClassRef(0) {

  if (Features.ObjC1) {
    if (Features.NeXTRuntime) {
      Runtime = CreateMacObjCRuntime(*this);
    } else {
      Runtime = CreateGNUObjCRuntime(*this);
    }
  }

  // If debug info generation is enabled, create the CGDebugInfo object.
  DebugInfo = GenerateDebugInfo ? new CGDebugInfo(this) : 0;      
}

CodeGenModule::~CodeGenModule() {
  delete Runtime;
  delete DebugInfo;
}

void CodeGenModule::Release() {
  EmitStatics();
  EmitAliases();
  if (Runtime)
    if (llvm::Function *ObjCInitFunction = Runtime->ModuleInitFunction())
      AddGlobalCtor(ObjCInitFunction);
  EmitCtorList(GlobalCtors, "llvm.global_ctors");
  EmitCtorList(GlobalDtors, "llvm.global_dtors");
  EmitAnnotations();
  BindRuntimeFunctions();
  // Run the verifier to check that the generated code is consistent.
  if (verifyModule(TheModule, llvm::PrintMessageAction)) {
    TheModule.dump();
    assert(0 && "Module failed verification!");
  }
}

void CodeGenModule::BindRuntimeFunctions() {
  // Deal with protecting runtime function names.
  for (unsigned i = 0, e = RuntimeFunctions.size(); i < e; ++i) {
    llvm::Function *Fn = RuntimeFunctions[i].first;
    const std::string &Name = RuntimeFunctions[i].second;
    
    // See if there is a conflict against a function.
    llvm::Function *Conflict = TheModule.getFunction(Name);
    if (Conflict) {
      // Decide which version to take. If the conflict is a definition
      // we are forced to take that, otherwise assume the runtime
      // knows best.
      if (!Conflict->isDeclaration()) {
        llvm::Value *Casted = 
          llvm::ConstantExpr::getBitCast(Conflict, Fn->getType());
        Fn->replaceAllUsesWith(Casted);
        Fn->eraseFromParent();
      } else {
        Fn->takeName(Conflict);
        llvm::Value *Casted = 
          llvm::ConstantExpr::getBitCast(Fn, Conflict->getType());
        Conflict->replaceAllUsesWith(Casted);
        Conflict->eraseFromParent();
      }
    } else {
      // FIXME: There still may be conflicts with aliases and
      // variables. 
      Fn->setName(Name);
    }
  }
}

/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified stmt yet.
void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type,
                                     bool OmitOnError) {
  if (OmitOnError && getDiags().hasErrorOccurred())
    return;
  unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error, 
                                               "cannot codegen this %0 yet");
  SourceRange Range = S->getSourceRange();
  std::string Msg = Type;
  getDiags().Report(Context.getFullLoc(S->getLocStart()), DiagID,
                    &Msg, 1, &Range, 1);
}

/// ErrorUnsupported - Print out an error that codegen doesn't support the
/// specified decl yet.
void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type,
                                     bool OmitOnError) {
  if (OmitOnError && getDiags().hasErrorOccurred())
    return;
  unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Error, 
                                               "cannot codegen this %0 yet");
  std::string Msg = Type;
  getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID,
                    &Msg, 1);
}

/// setGlobalVisibility - Set the visibility for the given LLVM
/// GlobalValue according to the given clang AST visibility value.
static void setGlobalVisibility(llvm::GlobalValue *GV,
                                VisibilityAttr::VisibilityTypes Vis) {
  switch (Vis) {
  default: assert(0 && "Unknown visibility!");
  case VisibilityAttr::DefaultVisibility:
    GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
    break;
  case VisibilityAttr::HiddenVisibility:
    GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
    break;
  case VisibilityAttr::ProtectedVisibility:
    GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
    break;
  }
}

/// AddGlobalCtor - Add a function to the list that will be called before
/// main() runs.
void CodeGenModule::AddGlobalCtor(llvm::Function * Ctor, int Priority) {
  // TODO: Type coercion of void()* types.
  GlobalCtors.push_back(std::make_pair(Ctor, Priority));
}

/// AddGlobalDtor - Add a function to the list that will be called
/// when the module is unloaded.
void CodeGenModule::AddGlobalDtor(llvm::Function * Dtor, int Priority) {
  // TODO: Type coercion of void()* types.
  GlobalDtors.push_back(std::make_pair(Dtor, Priority));
}

void CodeGenModule::EmitCtorList(const CtorList &Fns, const char *GlobalName) {
  // Ctor function type is void()*.
  llvm::FunctionType* CtorFTy =
    llvm::FunctionType::get(llvm::Type::VoidTy, 
                            std::vector<const llvm::Type*>(),
                            false);
  llvm::Type *CtorPFTy = llvm::PointerType::getUnqual(CtorFTy);

  // Get the type of a ctor entry, { i32, void ()* }.
  llvm::StructType* CtorStructTy = 
    llvm::StructType::get(llvm::Type::Int32Ty, 
                          llvm::PointerType::getUnqual(CtorFTy), NULL);

  // Construct the constructor and destructor arrays.
  std::vector<llvm::Constant*> Ctors;
  for (CtorList::const_iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
    std::vector<llvm::Constant*> S;
    S.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, I->second, false));
    S.push_back(llvm::ConstantExpr::getBitCast(I->first, CtorPFTy));
    Ctors.push_back(llvm::ConstantStruct::get(CtorStructTy, S));
  }

  if (!Ctors.empty()) {
    llvm::ArrayType *AT = llvm::ArrayType::get(CtorStructTy, Ctors.size());
    new llvm::GlobalVariable(AT, false,
                             llvm::GlobalValue::AppendingLinkage,
                             llvm::ConstantArray::get(AT, Ctors),
                             GlobalName, 
                             &TheModule);
  }
}

void CodeGenModule::EmitAnnotations() {
  if (Annotations.empty())
    return;