Commit c6e113f5 authored by Fabrice Bellard's avatar Fabrice Bellard
Browse files

added 'pure' function attribute - fixed indirect function calls 

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4469 c046a42c-6fe2-441c-8c8c-71466251a162
parent 0b6ce4cf

tcg/tcg.c

+42 −23
Original line number Diff line number Diff line
@@ -946,11 +946,28 @@ void tcg_liveness_analysis(TCGContext *s) 
        def = &tcg_op_defs[op];

        switch(op) {

        case INDEX_op_call:

            {

                int call_flags;



                nb_args = args[-1];

                args -= nb_args;

                nb_iargs = args[0] & 0xffff;

                nb_oargs = args[0] >> 16;

                args++;

                call_flags = args[nb_oargs + nb_iargs];



                /* pure functions can be removed if their result is not

                   used */

                if (call_flags & TCG_CALL_PURE) {

                    for(i = 0; i < nb_oargs; i++) {

                        arg = args[i];

                        if (!dead_temps[arg])

                            goto do_not_remove_call;

                    }

                    tcg_set_nop(s, gen_opc_buf + op_index, 

                                args - 1, nb_args);

                } else {

                do_not_remove_call:



                    /* output args are dead */

                    for(i = 0; i < nb_oargs; i++) {
@@ -971,7 +988,9 @@ void tcg_liveness_analysis(TCGContext *s) 
                        dead_temps[arg] = 0;

                    }

                    s->op_dead_iargs[op_index] = dead_iargs;

                }

                args--;

            }

            break;

        case INDEX_op_set_label:

            args--;
@@ -1640,7 +1659,7 @@ static int tcg_reg_alloc_call(TCGContext *s, const TCGOpDef *def, 
    }

    

    /* mark dead temporaries and free the associated registers */

    for(i = 0; i < nb_params; i++) {

    for(i = 0; i < nb_iargs; i++) {

        arg = args[nb_oargs + i];

        if (IS_DEAD_IARG(i)) {

            ts = &s->temps[arg];

tcg/tcg.h

+4 −0
Original line number Diff line number Diff line
@@ -148,6 +148,10 @@ typedef int TCGv; 
#define TCG_CALL_TYPE_REGPARM_1 0x0001 /* i386 style regparm call (1 reg) */

#define TCG_CALL_TYPE_REGPARM_2 0x0002 /* i386 style regparm call (2 regs) */

#define TCG_CALL_TYPE_REGPARM   0x0003 /* i386 style regparm call (3 regs) */

/* A pure function only reads its arguments and globals variables and

   cannot raise exceptions. Hence a call to a pure function can be

   safely suppressed if the return value is not used. */

#define TCG_CALL_PURE           0x0010 



typedef enum {

    TCG_COND_EQ,