// Copyright (c) 1999-2004 by Digital Mars
// All Rights Reserved
// written by Walter Bright
// www.digitalmars.com
// License for redistribution is by either the Artistic License
// in artistic.txt, or the GNU General Public License in gnu.txt.
// See the included readme.txt for details.

#include <cstddef>
#include <iostream>
#include <fstream>

#include "gen/llvm.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetMachineRegistry.h"

#include "mars.h"
#include "module.h"
#include "mtype.h"
#include "declaration.h"
#include "statement.h"
#include "enum.h"
#include "aggregate.h"
#include "init.h"
#include "attrib.h"
#include "id.h"
#include "import.h"
#include "template.h"
#include "scope.h"

#include "gen/irstate.h"
#include "gen/logger.h"
#include "gen/tollvm.h"
#include "gen/arrays.h"
#include "gen/structs.h"
#include "gen/classes.h"
#include "gen/functions.h"
#include "gen/todebug.h"
#include "gen/runtime.h"

//////////////////////////////////////////////////////////////////////////////////////////

void
Module::genobjfile()
{
    Logger::cout() << "Generating module: " << (md ? md->toChars() : toChars()) << '\n';
    LOG_SCOPE;

    // start by deleting the old object file
    deleteObjFile();

    // create a new ir state
    IRState ir;
    gIR = &ir;
    ir.dmodule = this;

    // name the module
    std::string mname(toChars());
    if (md != 0)
        mname = md->toChars();
    ir.module = new llvm::Module(mname);

    // set target stuff
    std::string target_triple(global.params.tt_arch);
    target_triple.append(global.params.tt_os);
    ir.module->setTargetTriple(target_triple);
    ir.module->setDataLayout(global.params.data_layout);

    // heavily inspired by tools/llc/llc.cpp:200-230
    const llvm::TargetMachineRegistry::Entry* targetEntry;
    std::string targetError;
    targetEntry = llvm::TargetMachineRegistry::getClosestStaticTargetForModule(*ir.module, targetError);
    assert(targetEntry && "Failed to find a static target for module");
    std::auto_ptr<llvm::TargetMachine> targetPtr(targetEntry->CtorFn(*ir.module, "")); // TODO: replace "" with features
    assert(targetPtr.get() && "Could not allocate target machine!");
    llvm::TargetMachine &targetMachine = *targetPtr.get();
    gTargetData = targetMachine.getTargetData();

    // debug info
    if (global.params.symdebug) {
        RegisterDwarfSymbols(ir.module);
        ir.dmodule->llvmCompileUnit = DtoDwarfCompileUnit(this,true);
    }

    // start out by providing opaque for the built-in class types
    if (!ClassDeclaration::object->type->llvmType)
        ClassDeclaration::object->type->llvmType = new llvm::PATypeHolder(llvm::OpaqueType::get());

    if (!Type::typeinfo->type->llvmType)
        Type::typeinfo->type->llvmType = new llvm::PATypeHolder(llvm::OpaqueType::get());

    if (!ClassDeclaration::classinfo->type->llvmType)
        ClassDeclaration::classinfo->type->llvmType = new llvm::PATypeHolder(llvm::OpaqueType::get());

    /*if (!Type::typeinfoclass->type->llvmType)
        Type::typeinfoclass->type->llvmType = new llvm::PATypeHolder(llvm::OpaqueType::get());*/

    // process module members
    for (int k=0; k < members->dim; k++) {
        Dsymbol* dsym = (Dsymbol*)(members->data[k]);
        assert(dsym);
        dsym->toObjFile();
    }

    // main driver loop
    DtoEmptyAllLists();
    // generate ModuleInfo
    genmoduleinfo();
    // do this again as moduleinfo might have pulled something in!
    DtoEmptyAllLists();

    gTargetData = 0;

    // emit the llvm main function if necessary
    if (ir.emitMain) {
        DtoMain();
    }

    // verify the llvm
    if (!global.params.novalidate) {
        std::string verifyErr;
        Logger::println("Verifying module...");
        LOG_SCOPE;
        if (llvm::verifyModule(*ir.module,llvm::ReturnStatusAction,&verifyErr))
        {
            error("%s", verifyErr.c_str());
            fatal();
        }
        else {
            Logger::println("Verification passed!");
        }
    }

    // run passes
    // TODO

    // write bytecode
    {
        Logger::println("Writing LLVM bitcode\n");
        std::ofstream bos(bcfile->name->toChars(), std::ios::binary);
        llvm::WriteBitcodeToFile(ir.module, bos);
    }

    // disassemble ?
    if (global.params.disassemble) {
        Logger::println("Writing LLVM asm to: %s\n", llfile->name->toChars());
        std::ofstream aos(llfile->name->toChars());
        ir.module->print(aos);
    }

    delete ir.module;
    gIR = NULL;
}

/* ================================================================== */

// build module ctor

static llvm::Function* build_module_ctor()
{
    if (gIR->ctors.empty())
        return NULL;

    size_t n = gIR->ctors.size();
    if (n == 1)
        return llvm::cast<llvm::Function>(gIR->ctors[0]->llvmValue);

    std::string name("_D");
    name.append(gIR->dmodule->mangle());
    name.append("6__ctorZ");

    std::vector<const llvm::Type*> argsTy;
    const llvm::FunctionType* fnTy = llvm::FunctionType::get(llvm::Type::VoidTy,argsTy,false);
    llvm::Function* fn = new llvm::Function(fnTy, llvm::GlobalValue::InternalLinkage, name, gIR->module);
    fn->setCallingConv(llvm::CallingConv::Fast);

    llvm::BasicBlock* bb = new llvm::BasicBlock("entry", fn);
    LLVMBuilder builder(bb);

    for (size_t i=0; i<n; i++) {
        llvm::Function* f = llvm::cast<llvm::Function>(gIR->ctors[i]->llvmValue);
        llvm::CallInst* call = builder.CreateCall(f,"");
        call->setCallingConv(llvm::CallingConv::Fast);
    }

    builder.CreateRetVoid();
    return fn;
}

// build module dtor

static llvm::Function* build_module_dtor()
{
    if (gIR->dtors.empty())
        return NULL;

    size_t n = gIR->dtors.size();
    if (n == 1)
        return llvm::cast<llvm::Function>(gIR->dtors[0]->llvmValue);

    std::string name("_D");
    name.append(gIR->dmodule->mangle());
    name.append("6__dtorZ");

    std::vector<const llvm::Type*> argsTy;
    const llvm::FunctionType* fnTy = llvm::FunctionType::get(llvm::Type::VoidTy,argsTy,false);
    llvm::Function* fn = new llvm::Function(fnTy, llvm::GlobalValue::InternalLinkage, name, gIR->module);
    fn->setCallingConv(llvm::CallingConv::Fast);

    llvm::BasicBlock* bb = new llvm::BasicBlock("entry", fn);
    LLVMBuilder builder(bb);

    for (size_t i=0; i<n; i++) {
        llvm::Function* f = llvm::cast<llvm::Function>(gIR->dtors[i]->llvmValue);
        llvm::CallInst* call = builder.CreateCall(f,"");
        call->setCallingConv(llvm::CallingConv::Fast);
    }

    builder.CreateRetVoid();
    return fn;
}

// Put out instance of ModuleInfo for this Module

void Module::genmoduleinfo()
{
//      The layout is:
//        {
//         void **vptr;
//         monitor_t monitor;
//         char[] name;        // class name
//         ModuleInfo importedModules[];
//         ClassInfo localClasses[];
//         uint flags;         // initialization state
//         void *ctor;
//         void *dtor;
//         void *unitTest;
//        }

    // resolve ModuleInfo
    assert(moduleinfo);
    DtoForceConstInitDsymbol(moduleinfo);

    // moduleinfo llvm struct type
    const llvm::StructType* moduleinfoTy = isaStruct(moduleinfo->type->llvmType->get());

    // classinfo llvm struct type
    const llvm::StructType* classinfoTy = isaStruct(ClassDeclaration::classinfo->type->llvmType->get());

    // initializer vector
    std::vector<llvm::Constant*> initVec;
    llvm::Constant* c = 0;

    // vtable
    c = moduleinfo->llvmVtbl;
    initVec.push_back(c);

    // monitor
    c = llvm::ConstantPointerNull::get(llvm::PointerType::get(llvm::Type::Int8Ty));
    initVec.push_back(c);

    // name
    char *name = toPrettyChars();
    c = DtoConstString(name);
    initVec.push_back(c);

    // importedModules[]
    int aimports_dim = aimports.dim;
    std::vector<llvm::Constant*> importInits;
    for (size_t i = 0; i < aimports.dim; i++)
    {
        Module *m = (Module *)aimports.data[i];
        if (!m->needModuleInfo())
            aimports_dim--;
        else { // declare
            // create name
            std::string m_name("_D");
            m_name.append(m->mangle());
            m_name.append("8__ModuleZ");
            llvm::GlobalVariable* m_gvar = new llvm::GlobalVariable(moduleinfoTy, false, llvm::GlobalValue::ExternalLinkage, NULL, m_name, gIR->module);
            importInits.push_back(m_gvar);
        }
    }
    // has import array?
    if (!importInits.empty()) {
        const llvm::ArrayType* importArrTy = llvm::ArrayType::get(llvm::PointerType::get(moduleinfoTy), importInits.size());
        c = llvm::ConstantArray::get(importArrTy, importInits);
        std::string m_name("_D");
        m_name.append(mangle());
        m_name.append("9__importsZ");
        llvm::GlobalVariable* m_gvar = new llvm::GlobalVariable(importArrTy, true, llvm::GlobalValue::InternalLinkage, c, m_name, gIR->module);
        c = llvm::ConstantExpr::getBitCast(m_gvar, llvm::PointerType::get(importArrTy->getElementType()));
        c = DtoConstSlice(DtoConstSize_t(importInits.size()), c);
    }
    else
        c = moduleinfo->llvmInitZ->getOperand(3);
    initVec.push_back(c);

    // localClasses[]
    ClassDeclarations aclasses;
    //printf("members->dim = %d\n", members->dim);
    for (size_t i = 0; i < members->dim; i++)
    {
        Dsymbol *member;

        member = (Dsymbol *)members->data[i];
        //printf("\tmember '%s'\n", member->toChars());
        member->addLocalClass(&aclasses);
    }
    // fill inits
    std::vector<llvm::Constant*> classInits;
    for (size_t i = 0; i < aclasses.dim; i++)
    {
        ClassDeclaration* cd = (ClassDeclaration*)aclasses.data[i];
        assert(cd->llvmClass);
        classInits.push_back(cd->llvmClass);
    }
    // has class array?
    if (!classInits.empty()) {
        const llvm::ArrayType* classArrTy = llvm::ArrayType::get(llvm::PointerType::get(classinfoTy), classInits.size());
        c = llvm::ConstantArray::get(classArrTy, classInits);
        std::string m_name("_D");
        m_name.append(mangle());
        m_name.append("9__classesZ");
        llvm::GlobalVariable* m_gvar = new llvm::GlobalVariable(classArrTy, true, llvm::GlobalValue::InternalLinkage, c, m_name, gIR->module);
        c = llvm::ConstantExpr::getBitCast(m_gvar, llvm::PointerType::get(classArrTy->getElementType()));
        c = DtoConstSlice(DtoConstSize_t(classInits.size()), c);
    }
    else
        c = moduleinfo->llvmInitZ->getOperand(4);
    initVec.push_back(c);

    // flags
    if (needmoduleinfo)
        c = DtoConstUint(0);        // flags (4 means MIstandalone)
    else
        c = DtoConstUint(4);        // flags (4 means MIstandalone)
    initVec.push_back(c);

    // ctor
    llvm::Function* fctor = build_module_ctor();
    c = fctor ? fctor : moduleinfo->llvmInitZ->getOperand(6);
    initVec.push_back(c);

    // dtor
    llvm::Function* fdtor = build_module_dtor();
    c = fdtor ? fdtor : moduleinfo->llvmInitZ->getOperand(7);
    initVec.push_back(c);

    // unitTest
    c = moduleinfo->llvmInitZ->getOperand(8);
    initVec.push_back(c);

    // create initializer
    llvm::Constant* constMI = llvm::ConstantStruct::get(moduleinfoTy, initVec);

    // create name
    std::string MIname("_D");
    MIname.append(mangle());
    MIname.append("8__ModuleZ");

    // declare
    // flags will be modified at runtime so can't make it constant
    llvm::GlobalVariable* gvar = new llvm::GlobalVariable(moduleinfoTy, false, llvm::GlobalValue::ExternalLinkage, constMI, MIname, gIR->module);

    // declare the appending array
    const llvm::ArrayType* appendArrTy = llvm::ArrayType::get(llvm::PointerType::get(llvm::Type::Int8Ty), 1);
    std::vector<llvm::Constant*> appendInits;
    appendInits.push_back(llvm::ConstantExpr::getBitCast(gvar, llvm::PointerType::get(llvm::Type::Int8Ty)));
    llvm::Constant* appendInit = llvm::ConstantArray::get(appendArrTy, appendInits);
    std::string appendName("_d_moduleinfo_array");
    llvm::GlobalVariable* appendVar = new llvm::GlobalVariable(appendArrTy, true, llvm::GlobalValue::AppendingLinkage, appendInit, appendName, gIR->module);
}

/* ================================================================== */

void Dsymbol::toObjFile()
{
    Logger::println("Ignoring Dsymbol::toObjFile for %s", toChars());
}

/* ================================================================== */

void Declaration::toObjFile()
{
    Logger::println("Ignoring Declaration::toObjFile for %s", toChars());
}

/* ================================================================== */

void InterfaceDeclaration::toObjFile()
{
    Logger::println("Ignoring InterfaceDeclaration::toObjFile for %s", toChars());
}

/* ================================================================== */

void StructDeclaration::toObjFile()
{
    gIR->resolveList.push_back(this);
}

/* ================================================================== */

static unsigned LLVM_ClassOffsetToIndex(ClassDeclaration* cd, unsigned os, unsigned& idx)
{
    // start at the bottom of the inheritance chain
    if (cd->baseClass != 0) {
        unsigned o = LLVM_ClassOffsetToIndex(cd->baseClass, os, idx);
        if (o != (unsigned)-1)
            return o;
    }

    // check this class
    unsigned i;
    for (i=0; i<cd->fields.dim; ++i) {
        VarDeclaration* vd = (VarDeclaration*)cd->fields.data[i];
        if (os == vd->offset)
            return i+idx;
    }
    idx += i;

    return (unsigned)-1;
}

void ClassDeclaration::offsetToIndex(Type* t, unsigned os, std::vector<unsigned>& result)
{
    unsigned idx = 0;
    unsigned r = LLVM_ClassOffsetToIndex(this, os, idx);
    assert(r != (unsigned)-1 && "Offset not found in any aggregate field");
    // vtable is 0, monitor is 1
    r += 2;
    // interface offset further
    r += vtblInterfaces->dim;
    // the final index was not pushed
    result.push_back(r); 
}

/* ================================================================== */

void ClassDeclaration::toObjFile()
{
    gIR->resolveList.push_back(this);
}

/******************************************
 * Get offset of base class's vtbl[] initializer from start of csym.
 * Returns ~0 if not this csym.
 */

unsigned ClassDeclaration::baseVtblOffset(BaseClass *bc)
{
  return ~0;
}

/* ================================================================== */

void VarDeclaration::toObjFile()
{
    Logger::print("VarDeclaration::toObjFile(): %s | %s\n", toChars(), type->toChars());
    LOG_SCOPE;

    if (aliassym)
    {
        Logger::println("alias sym");
        toAlias()->toObjFile();
        return;
    }

    // global variable or magic
    if (isDataseg())
    {
        if (llvmResolved) return;
        llvmResolved = true;
        llvmDeclared = true;

        llvmIRGlobal = new IRGlobal(this);

        Logger::println("parent: %s (%s)", parent->toChars(), parent->kind());

        bool _isconst = isConst();
        if (parent && parent->isFuncDeclaration() && init && init->isExpInitializer())
            _isconst = false;

        llvm::GlobalValue::LinkageTypes _linkage;
        bool istempl = false;
        bool static_local = false;
        if ((storage_class & STCcomdat) || (parent && DtoIsTemplateInstance(parent))) {
            _linkage = llvm::GlobalValue::WeakLinkage;
            istempl = true;
        }
        else if (parent && parent->isFuncDeclaration()) {
            _linkage = llvm::GlobalValue::InternalLinkage;
            static_local = true;
        }
        else
            _linkage = DtoLinkage(protection, storage_class);

        const llvm::Type* _type = llvmIRGlobal->type.get();

        Logger::println("Creating global variable");
        std::string _name(mangle());

        llvm::GlobalVariable* gvar = new llvm::GlobalVariable(_type,_isconst,_linkage,NULL,_name,gIR->module);
        llvmValue = gvar;

        if (static_local)
            DtoConstInitGlobal(this);
        else
            gIR->constInitList.push_back(this);

        //if (storage_class & STCprivate)
        //    gvar->setVisibility(llvm::GlobalValue::ProtectedVisibility);
    }

    // inside aggregate declaration. declare a field.
    else
    {
        Logger::println("Aggregate var declaration: '%s' offset=%d", toChars(), offset);

        const llvm::Type* _type = DtoType(type);

        // add the field in the IRStruct
        gIR->topstruct()->offsets.insert(std::make_pair(offset, IRStruct::Offset(this, _type)));
    }

    Logger::println("VarDeclaration::toObjFile is done");
}

/* ================================================================== */

void TypedefDeclaration::toObjFile()
{
    static int tdi = 0;
    Logger::print("TypedefDeclaration::toObjFile(%d): %s\n", tdi++, toChars());
    LOG_SCOPE;

    // generate typeinfo
    type->getTypeInfo(NULL);
}

/* ================================================================== */

void EnumDeclaration::toObjFile()
{
    Logger::println("Ignoring EnumDeclaration::toObjFile for %s", toChars());
}

/* ================================================================== */

void FuncDeclaration::toObjFile()
{
    gIR->resolveList.push_back(this);
}