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();
  // Run the verifier to check that the generated code is consistent.
  if (verifyModule(TheModule, llvm::PrintMessageAction)) {
    TheModule.dump();
    assert(0 && "Module failed verification!");
  }
}

/// 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;

  // Create a new global variable for the ConstantStruct in the Module.
  llvm::Constant *Array =
  llvm::ConstantArray::get(llvm::ArrayType::get(Annotations[0]->getType(),
                                                Annotations.size()),
                           Annotations);
  llvm::GlobalValue *gv = 
  new llvm::GlobalVariable(Array->getType(), false,  
                           llvm::GlobalValue::AppendingLinkage, Array, 
                           "llvm.global.annotations", &TheModule);
  gv->setSection("llvm.metadata");
}

static void SetGlobalValueAttributes(const Decl *D, 
                                     bool IsInternal,
                                     bool IsInline,
                                     llvm::GlobalValue *GV,
                                     bool ForDefinition) {
  // TODO: Set up linkage and many other things.  Note, this is a simple 
  // approximation of what we really want.
  if (!ForDefinition) {
    // Only a few attributes are set on declarations.
    if (D->getAttr<DLLImportAttr>())
      GV->setLinkage(llvm::Function::DLLImportLinkage);
  } else {
    if (IsInternal) {
      GV->setLinkage(llvm::Function::InternalLinkage);
    } else {
      if (D->getAttr<DLLImportAttr>())
        GV->setLinkage(llvm::Function::DLLImportLinkage);
      else if (D->getAttr<DLLExportAttr>())
        GV->setLinkage(llvm::Function::DLLExportLinkage);
      else if (D->getAttr<WeakAttr>() || IsInline)
        GV->setLinkage(llvm::Function::WeakLinkage);