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#ifndef __nanojit_Assembler__
#define __nanojit_Assembler__


namespace nanojit
{
    /**
     * Some notes on this Assembler (Emitter).
     *
     *   The class RegAlloc is essentially the register allocator from MIR
     *
     *   The Assembler class parses the LIR instructions starting at any point and converts
     *   them to machine code.  It does the translation using expression trees which are simply
     *   LIR instructions in the stream that have side-effects.  Any other instruction in the
     *   stream is simply ignored.
     *   This approach is interesting in that dead code elimination occurs for 'free', strength
     *   reduction occurs fairly naturally, along with some other optimizations.
     *
     *   A negative is that we require state as we 'push' and 'pop' nodes along the tree.
     *   Also, this is most easily performed using recursion which may not be desirable in
     *   the mobile environment.
     *
     */

    #define STACK_GRANULARITY        sizeof(void *)

    // Basics:
    // - 'entry' records the state of the native machine stack at particular
    //   points during assembly.  Each entry represents four bytes.
    //
    // - Parts of the stack can be allocated by LIR_ialloc, in which case each
    //   slot covered by the allocation contains a pointer to the LIR_ialloc
    //   LIns.
    //
    // - The stack also holds spilled values, in which case each slot holding
    //   a spilled value (one slot for 32-bit values, two slots for 64-bit
    //   values) contains a pointer to the instruction defining the spilled
    //   value.
    //
    // - Each LIns has a "reservation" which includes a stack index,
    //   'arIndex'.  Combined with AR, it provides a two-way mapping between
    //   stack slots and LIR instructions.
    //
    // - Invariant: the two-way mapping between active stack slots and their
    //   defining/allocating instructions must hold in both directions and be
    //   unambiguous.  More specifically:
    //
    //   * An LIns can appear in at most one contiguous sequence of slots in
    //     AR, and the length of that sequence depends on the opcode (1 slot
    //     for instructions producing 32-bit values, 2 slots for instructions
    //     producing 64-bit values, N slots for LIR_ialloc).
    //
    //   * An LIns named by 'entry[i]' must have an in-use reservation with
    //     arIndex==i (or an 'i' indexing the start of the same contiguous
    //     sequence that 'entry[i]' belongs to).
    //
    //   * And vice versa:  an LIns with an in-use reservation with arIndex==i
    //     must be named by 'entry[i]'.
    //
    //   * If an LIns's reservation names has arIndex==0 then LIns should not
    //     be in 'entry[]'.
    //
    class AR
    {
    private:
        uint32_t        _highWaterMark;                 /* index of highest entry used since last clear() */
        LIns*           _entries[ NJ_MAX_STACK_ENTRY ]; /* maps to 4B contiguous locations relative to the frame pointer.
                                                            NB: _entries[0] is always unused */

        #ifdef _DEBUG
        static LIns* const BAD_ENTRY;
        #endif

        bool isEmptyRange(uint32_t start, uint32_t nStackSlots) const;
        static uint32_t nStackSlotsFor(LIns* ins);

    public:
        AR();
        
        uint32_t stackSlotsNeeded() const;

        void clear();
        void freeEntryAt(uint32_t i);
        uint32_t reserveEntry(LIns* ins); /* return 0 if unable to reserve the entry */

        #ifdef _DEBUG
        void validateQuick();
        void validateFull();
        void validate();
        bool isValidEntry(uint32_t idx, LIns* ins) const; /* return true iff idx and ins are matched */
        void checkForResourceConsistency(const RegAlloc& regs);
        void checkForResourceLeaks() const;
        #endif

        class Iter
        {
        private:
            const AR& _ar;
            uint32_t _i;
        public:
            inline Iter(const AR& ar) : _ar(ar), _i(1) { }
            bool next(LIns*& ins, uint32_t& nStackSlots, int32_t& offset);             // get the next one (moves iterator forward)
        };
    };

    inline AR::AR()
    {
         _entries[0] = NULL; 
         clear();
    }

    inline /*static*/ uint32_t AR::nStackSlotsFor(LIns* ins)
    {
        return ins->isop(LIR_alloc) ? (ins->size()>>2) : (ins->isQuad() ? 2 : 1);
    }

    inline uint32_t AR::stackSlotsNeeded() const
    {
        // NB: _highWaterMark is an index, not a count
        return _highWaterMark+1;
    }

    #ifndef AVMPLUS_ALIGN16
        #ifdef AVMPLUS_WIN32
            #define AVMPLUS_ALIGN16(type) __declspec(align(16)) type
        #else
            #define AVMPLUS_ALIGN16(type) type __attribute__ ((aligned (16)))
        #endif
    #endif

    struct Stats
    {
        counter_define(steals;)
        counter_define(remats;)
        counter_define(spills;)
        counter_define(native;)
        counter_define(exitnative;)

        int32_t pages;
        NIns* codeStart;
        NIns* codeExitStart;

        DECLARE_PLATFORM_STATS()
#ifdef __GNUC__
        // inexplicably, gnuc gives padding/alignment warnings without this. pacify it.
        bool pad[4];
#endif
    };

    // error codes
    enum AssmError
    {
         None = 0
        ,StackFull
        ,UnknownBranch
    };

    typedef SeqBuilder<NIns*> NInsList;
    typedef HashMap<NIns*, LIns*> NInsMap;

#ifdef VTUNE
    class avmplus::CodegenLIR;
#endif

    class LabelState
    {
    public:
        RegAlloc regs;
        NIns *addr;
        LabelState(NIns *a, RegAlloc &r) : regs(r), addr(a)
        {}
    };

    class LabelStateMap
    {
        Allocator& alloc;
        HashMap<LIns*, LabelState*> labels;
    public:
        LabelStateMap(Allocator& alloc) : alloc(alloc), labels(alloc)
        {}

        void clear() { labels.clear(); }
        void add(LIns *label, NIns *addr, RegAlloc &regs);
        LabelState *get(LIns *);
    };

    typedef SeqBuilder<char*> StringList;

    /** map tracking the register allocation state at each bailout point
     *  (represented by SideExit*) in a trace fragment. */
    typedef HashMap<SideExit*, RegAlloc*> RegAllocMap;

    /**
     * Information about the activation record for the method is built up
     * as we generate machine code.  As part of the prologue, we issue
     * a stack adjustment instruction and then later patch the adjustment
     * value.  Temporary values can be placed into the AR as method calls
     * are issued.   Also LIR_alloc instructions will consume space.
     */
    class Assembler
    {
        friend class VerboseBlockReader;
        public:
            #ifdef NJ_VERBOSE
            // Log controller object.  Contains what-stuff-should-we-print
            // bits, and a sink function for debug printing.
            LogControl* _logc;
            // Buffer for holding text as we generate it in reverse order.
            StringList* _outputCache;

            // Outputs the format string and 'outlineEOL', and resets
            // 'outline' and 'outlineEOL'.
            void outputf(const char* format, ...);

        private:
            // Buffer used in most of the output function.  It must big enough
            // to hold both the output line and the 'outlineEOL' buffer, which
            // is concatenated onto 'outline' just before it is printed.
            static char  outline[8192];
            // Buffer used to hold extra text to be printed at the end of some
            // lines.
            static char  outlineEOL[512];

            // Outputs 'outline' and 'outlineEOL', and resets them both.
            // Output goes to '_outputCache' if it's non-NULL, or is printed
            // directly via '_logc'.
            void output();

            // Sets 'outlineEOL'.
            void setOutputForEOL(const char* format, ...);

            void printRegState();
            void printActivationState();
            #endif // NJ_VERBOSE

        public:
            #ifdef VTUNE
            avmplus::CodegenLIR *cgen;
            #endif

            Assembler(CodeAlloc& codeAlloc, Allocator& dataAlloc, Allocator& alloc, AvmCore* core, LogControl* logc);

            void        endAssembly(Fragment* frag);
            void        assemble(Fragment* frag, LirFilter* reader);
            void        beginAssembly(Fragment *frag);

            void        releaseRegisters();
            void        patch(GuardRecord *lr);
            void        patch(SideExit *exit);
#ifdef NANOJIT_IA32
            void        patch(SideExit *exit, SwitchInfo* si);
#endif
            AssmError   error()    { return _err; }
            void        setError(AssmError e) { _err = e; }

            void        reset();

            debug_only ( void       pageValidate(); )

            // support calling out from a fragment ; used to debug the jit
            debug_only( void        resourceConsistencyCheck(); )
            debug_only( void        registerConsistencyCheck(); )

            Stats       _stats;
            CodeList*   codeList;                   // finished blocks of code.

        private:

            void        gen(LirFilter* toCompile);
            NIns*       genPrologue();
            NIns*       genEpilogue();

            uint32_t    arReserve(LIns* ins);
            void        arFreeIfInUse(LIns* ins);
            void        arReset();

            Register    registerAlloc(LIns* ins, RegisterMask allow);
            Register    registerAllocTmp(RegisterMask allow);
            void        registerResetAll();
            void        evictAllActiveRegs();
            void        evictSomeActiveRegs(RegisterMask regs);
            void        evictScratchRegs();
            void        intersectRegisterState(RegAlloc& saved);
            void        unionRegisterState(RegAlloc& saved);
            void        assignSaved(RegAlloc &saved, RegisterMask skip);
            LInsp       findVictim(RegisterMask allow);

            Register    getBaseReg(LIns *i, int &d, RegisterMask allow);
            int         findMemFor(LIns* i);
            Register    findRegFor(LIns* i, RegisterMask allow);
            void        findRegFor2(RegisterMask allow, LIns* ia, Register &ra, LIns *ib, Register &rb);
            Register    findSpecificRegFor(LIns* i, Register r);
            Register    findSpecificRegForUnallocated(LIns* i, Register r);
            Register    prepResultReg(LIns *i, RegisterMask allow);
            Register    prepareResultReg(LIns *i, RegisterMask allow);
            void        freeRsrcOf(LIns *i, bool pop);
            void        freeResourcesOf(LIns *ins);
            void        evictIfActive(Register r);
            void        evict(LIns* vic);
            RegisterMask hint(LIns*i, RegisterMask allow);

            void        codeAlloc(NIns *&start, NIns *&end, NIns *&eip
                                  verbose_only(, size_t &nBytes));
            bool        canRemat(LIns*);

            bool isKnownReg(Register r) {
                return r != UnknownReg;
            }

            Allocator&          alloc;              // for items with same lifetime as this Assembler
            CodeAlloc&          _codeAlloc;         // for code we generate
            Allocator&          _dataAlloc;         // for data used by generated code
            Fragment*           _thisfrag;
            RegAllocMap         _branchStateMap;
            NInsMap             _patches;
            LabelStateMap       _labels;

            // We generate code into two places:  normal code chunks, and exit
            // code chunks (for exit stubs).  We use a hack to avoid having to
            // parameterise the code that does the generating -- we let that
            // code assume that it's always generating into a normal code
            // chunk (most of the time it is), and when we instead need to
            // generate into an exit code chunk, we set _inExit to true and
            // temporarily swap all the code/exit variables below (using
            // swapCodeChunks()).  Afterwards we swap them all back and set
            // _inExit to false again.
            bool        _inExit, vpad2[3];
            NIns        *codeStart, *codeEnd;   // current normal code chunk
            NIns        *exitStart, *exitEnd;   // current exit code chunk
            NIns*       _nIns;                  // current instruction in current normal code chunk
            NIns*       _nExitIns;              // current instruction in current exit code chunk
        #ifdef NJ_VERBOSE
        public:
            size_t      codeBytes;              // bytes allocated in normal code chunks
            size_t      exitBytes;              // bytes allocated in exit code chunks
        #endif

        private:
            #define     SWAP(t, a, b)   do { t tmp = a; a = b; b = tmp; } while (0)
            void        swapCodeChunks();

            NIns*       _epilogue;
            AssmError   _err;           // 0 = means assemble() appears ok, otherwise it failed
        #if PEDANTIC
            NIns*       pedanticTop;
        #endif

            AR          _activation;
            RegAlloc    _allocator;

            verbose_only( void asm_inc_m32(uint32_t*); )
            void        asm_mmq(Register rd, int dd, Register rs, int ds);
            NIns*       asm_exit(LInsp guard);
            NIns*       asm_leave_trace(LInsp guard);
            void        asm_qjoin(LIns *ins);
            void        asm_store32(LOpcode op, LIns *val, int d, LIns *base);
            void        asm_store64(LOpcode op, LIns *val, int d, LIns *base);
            void        asm_restore(LInsp, Register);
            void        asm_spilli(LInsp i, bool pop);
            void        asm_spill(Register rr, int d, bool pop, bool quad);
            void        asm_load64(LInsp i);
            void        asm_ret(LInsp p);
            void        asm_quad(LInsp i);
            void        asm_fcond(LInsp i);
            void        asm_cond(LInsp i);
            void        asm_arith(LInsp i);
            void        asm_neg_not(LInsp i);
            void        asm_load32(LInsp i);
            void        asm_cmov(LInsp i);
            void        asm_param(LInsp i);
            void        asm_int(LInsp i);
            void        asm_qlo(LInsp i);
            void        asm_qhi(LInsp i);
            void        asm_fneg(LInsp ins);
            void        asm_fop(LInsp ins);
            void        asm_i2f(LInsp ins);
            void        asm_u2f(LInsp ins);
            void        asm_promote(LIns *ins);
            void        asm_nongp_copy(Register r, Register s);
            void        asm_call(LInsp);
            Register    asm_binop_rhs_reg(LInsp ins);
            NIns*       asm_branch(bool branchOnFalse, LInsp cond, NIns* targ);
            void        asm_switch(LIns* ins, NIns* target);
            void        asm_jtbl(LIns* ins, NIns** table);
            void        emitJumpTable(SwitchInfo* si, NIns* target);
            void        assignSavedRegs();
            void        reserveSavedRegs();
            void        assignParamRegs();
            void        handleLoopCarriedExprs(InsList& pending_lives);

            // platform specific implementation (see NativeXXX.cpp file)
            void        nInit(AvmCore *);
            void        nBeginAssembly();
            Register    nRegisterAllocFromSet(RegisterMask set);
            void        nRegisterResetAll(RegAlloc& a);
            static void nPatchBranch(NIns* branch, NIns* location);
            void        nFragExit(LIns* guard);

            // platform specific methods
        public:
            const static Register savedRegs[NumSavedRegs];
            DECLARE_PLATFORM_ASSEMBLER()

        private:
#ifdef NANOJIT_IA32
            debug_only( int32_t _fpuStkDepth; )
            debug_only( int32_t _sv_fpuStkDepth; )

            // since we generate backwards the depth is negative
            inline void fpu_push() {
                debug_only( ++_fpuStkDepth; NanoAssert(_fpuStkDepth<=0); )
            }
            inline void fpu_pop() {
                debug_only( --_fpuStkDepth; NanoAssert(_fpuStkDepth<=0); )
            }
#endif
            avmplus::Config &config;
    };

    inline int32_t disp(LIns* ins)
    {
        // even on 64bit cpu's, we allocate stack area in 4byte chunks
        return -4 * int32_t(ins->getArIndex());
    }
}
#endif // __nanojit_Assembler__
