//===-- gen/irstate.h - Global codegen state --------------------*- C++ -*-===//
//
//                         LDC – the LLVM D compiler
//
// This file is distributed under the BSD-style LDC license. See the LICENSE
// file for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the global state used and modified when generating the
// code (i.e. LLVM IR) for a given D module.
//
//===----------------------------------------------------------------------===//

#ifndef LDC_GEN_IRSTATE_H
#define LDC_GEN_IRSTATE_H

#include "aggregate.h"
#include "root.h"
#include "ir/irfunction.h"
#include "ir/iraggr.h"
#include "ir/irvar.h"
#include "gen/dibuilder.h"
#include <deque>
#include <list>
#include <sstream>
#include <vector>

#include "llvm/Support/CallSite.h"

namespace llvm {
    class LLVMContext;
    class TargetMachine;
}

// global ir state for current module
struct IRState;
struct TargetABI;

extern IRState* gIR;
extern llvm::TargetMachine* gTargetMachine;
#if LDC_LLVM_VER >= 302
extern const llvm::DataLayout* gDataLayout;
#else
extern const llvm::TargetData* gDataLayout;
#endif
extern TargetABI* gABI;

struct TypeFunction;
struct TypeStruct;
struct ClassDeclaration;
struct FuncDeclaration;
struct Module;
struct TypeStruct;
struct BaseClass;
struct AnonDeclaration;

struct IrModule;

// represents a scope
struct IRScope
{
    llvm::BasicBlock* begin;
    llvm::BasicBlock* end;
    IRBuilder<> builder;

    IRScope();
    IRScope(llvm::BasicBlock* b, llvm::BasicBlock* e);

    const IRScope& operator=(const IRScope& rhs);
};

struct IRBuilderHelper
{
    IRState* state;
    IRBuilder<>* operator->();
};

struct IRAsmStmt
{
    IRAsmStmt()
    : isBranchToLabel(NULL) {}

    std::string code;
    std::string out_c;
    std::string in_c;
    std::vector<LLValue*> out;
    std::vector<LLValue*> in;

    // if this is nonzero, it contains the target label
    Identifier* isBranchToLabel;
};

struct IRAsmBlock
{
    std::deque<IRAsmStmt*> s;
    std::set<std::string> clobs;
    size_t outputcount;

    // stores the labels within the asm block
    std::vector<Identifier*> internalLabels;

    AsmBlockStatement* asmBlock;
    LLType* retty;
    unsigned retn;
    bool retemu; // emulate abi ret with a temporary
    LLValue* (*retfixup)(IRBuilderHelper b, LLValue* orig); // Modifies retval

    IRAsmBlock(AsmBlockStatement* b)
        : outputcount(0), asmBlock(b), retty(NULL), retn(0), retemu(false),
        retfixup(NULL)
    {}
};

// represents the module
struct IRState
{
    IRState(llvm::Module* m);

    // module
    Module* dmodule;
    llvm::Module* module;

    // interface info type, used in DtoInterfaceInfoType
    LLStructType* interfaceInfoType;
    LLStructType* mutexType;
    LLStructType* moduleRefType;

    // helper to get the LLVMContext of the module
    llvm::LLVMContext& context() const { return module->getContext(); }

    // functions
    typedef std::vector<IrFunction*> FunctionVector;
    FunctionVector functions;
    IrFunction* func();

    llvm::Function* topfunc();
    TypeFunction* topfunctype();
    llvm::Instruction* topallocapoint();

    // structs
    typedef std::vector<IrAggr*> StructVector;
    StructVector structs;
    IrAggr* topstruct();

    // D main function
    bool emitMain;
    llvm::Function* mainFunc;

    // basic block scopes
    std::vector<IRScope> scopes;
    IRScope& scope();
    llvm::BasicBlock* scopebb();
    llvm::BasicBlock* scopeend();
    bool scopereturned();

    // create a call or invoke, depending on the landing pad info
    // the template function is defined further down in this file
    template <typename T>
    llvm::CallSite CreateCallOrInvoke(LLValue* Callee, const T& args, const char* Name="");
    llvm::CallSite CreateCallOrInvoke(LLValue* Callee, const char* Name="");
    llvm::CallSite CreateCallOrInvoke(LLValue* Callee, LLValue* Arg1, const char* Name="");
    llvm::CallSite CreateCallOrInvoke2(LLValue* Callee, LLValue* Arg1, LLValue* Arg2, const char* Name="");
    llvm::CallSite CreateCallOrInvoke3(LLValue* Callee, LLValue* Arg1, LLValue* Arg2, LLValue* Arg3, const char* Name="");
    llvm::CallSite CreateCallOrInvoke4(LLValue* Callee, LLValue* Arg1, LLValue* Arg2,  LLValue* Arg3, LLValue* Arg4, const char* Name="");

    // this holds the array being indexed or sliced so $ will work
    // might be a better way but it works. problem is I only get a
    // VarDeclaration for __dollar, but I can't see how to get the
    // array pointer from this :(
    std::vector<DValue*> arrays;

    // builder helper
    IRBuilderHelper ir;

    // debug info helper
    ldc::DIBuilder DBuilder;

    // static ctors/dtors/unittests
    typedef std::list<FuncDeclaration*> FuncDeclList;
    typedef std::list<VarDeclaration*> GatesList;
    FuncDeclList ctors;
    FuncDeclList dtors;
    FuncDeclList sharedCtors;
    FuncDeclList sharedDtors;
    GatesList gates;
    GatesList sharedGates;
    FuncDeclList unitTests;

    // all template instances that had members emitted
    // currently only filled for singleobj
    // used to make sure the complete template instance gets emitted in the
    // first file that touches a member, see #318
    typedef std::set<TemplateInstance*> TemplateInstanceSet;
    TemplateInstanceSet seenTemplateInstances;

    // for inline asm
    IRAsmBlock* asmBlock;
    std::ostringstream nakedAsm;

    // 'used' array solely for keeping a reference to globals
    std::vector<LLConstant*> usedArray;

    /// Whether to emit array bounds checking in the current function.
    bool emitArrayBoundsChecks();

#if LDC_LLVM_VER >= 303
    /// Vector of options passed to the linker as metadata in object file.
    llvm::SmallVector<llvm::Value *, 5> LinkerMetadataArgs;
#endif
};

template <typename T>
llvm::CallSite IRState::CreateCallOrInvoke(LLValue* Callee, const T &args, const char* Name)
{
    llvm::BasicBlock* pad = func()->gen->landingPad;
    if(pad)
    {
        // intrinsics don't support invoking and 'nounwind' functions don't need it.
        LLFunction* funcval = llvm::dyn_cast<LLFunction>(Callee);
        if (funcval && (funcval->isIntrinsic() || funcval->doesNotThrow()))
        {
            llvm::CallInst* call = ir->CreateCall(Callee, args, Name);
            call->setAttributes(funcval->getAttributes());
            return call;
        }

        llvm::BasicBlock* postinvoke = llvm::BasicBlock::Create(gIR->context(), "postinvoke", topfunc(), scopeend());
        llvm::InvokeInst* invoke = ir->CreateInvoke(Callee, postinvoke, pad, args, Name);
        if (LLFunction* fn = llvm::dyn_cast<LLFunction>(Callee))
            invoke->setAttributes(fn->getAttributes());
        scope() = IRScope(postinvoke, scopeend());
        return invoke;
    }
    else
    {
        llvm::CallInst* call = ir->CreateCall(Callee, args, Name);
        if (LLFunction* fn = llvm::dyn_cast<LLFunction>(Callee))
            call->setAttributes(fn->getAttributes());
        return call;
    }
}

#endif // LDC_GEN_IRSTATE_H