gwj / at91sam9263 · Files

/*
 * Tiny Code Generator for QEMU
 *
 * Copyright (c) 2008 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/* define it to suppress various consistency checks (faster) */
#define NDEBUG

/* define it to use liveness analysis (better code) */
#define USE_LIVENESS_ANALYSIS

#include <assert.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <inttypes.h>

#ifdef _WIN32
#include <malloc.h>
#endif

#include "config.h"

#include "qemu-common.h"

/* Note: the long term plan is to reduce the dependancies on the QEMU
   CPU definitions. Currently they are used for qemu_ld/st
   instructions */
#define NO_CPU_IO_DEFS
#include "cpu.h"
#include "exec-all.h"

#include "tcg-op.h"
#include "elf.h"


static void patch_reloc(uint8_t *code_ptr, int type, 

                        tcg_target_long value, tcg_target_long addend);

TCGOpDef tcg_op_defs[] = {
#define DEF(s, n, copy_size) { #s, 0, 0, n, n, 0, copy_size },
#define DEF2(s, iargs, oargs, cargs, flags) { #s, iargs, oargs, cargs, iargs + oargs + cargs, flags, 0 },
#include "tcg-opc.h"
#undef DEF
#undef DEF2
};

TCGRegSet tcg_target_available_regs[2];
TCGRegSet tcg_target_call_clobber_regs;

/* XXX: move that inside the context */
uint16_t *gen_opc_ptr;
TCGArg *gen_opparam_ptr;

static inline void tcg_out8(TCGContext *s, uint8_t v)
{
    *s->code_ptr++ = v;
}

static inline void tcg_out16(TCGContext *s, uint16_t v)
{
    *(uint16_t *)s->code_ptr = v;
    s->code_ptr += 2;
}

static inline void tcg_out32(TCGContext *s, uint32_t v)
{
    *(uint32_t *)s->code_ptr = v;
    s->code_ptr += 4;
}

/* label relocation processing */

void tcg_out_reloc(TCGContext *s, uint8_t *code_ptr, int type, 
                   int label_index, long addend)
{
    TCGLabel *l;
    TCGRelocation *r;

    l = &s->labels[label_index];
    if (l->has_value) {

        /* FIXME: This may break relocations on RISC targets that
           modify instruction fields in place.  The caller may not have 
           written the initial value.  */

        patch_reloc(code_ptr, type, l->u.value, addend);

    } else {
        /* add a new relocation entry */
        r = tcg_malloc(sizeof(TCGRelocation));
        r->type = type;
        r->ptr = code_ptr;
        r->addend = addend;
        r->next = l->u.first_reloc;
        l->u.first_reloc = r;
    }
}

static void tcg_out_label(TCGContext *s, int label_index, 
                          tcg_target_long value)
{
    TCGLabel *l;
    TCGRelocation *r;

    l = &s->labels[label_index];
    if (l->has_value)
        tcg_abort();
    r = l->u.first_reloc;
    while (r != NULL) {

        patch_reloc(r->ptr, r->type, value, r->addend);

        r = r->next;
    }
    l->has_value = 1;
    l->u.value = value;
}

int gen_new_label(void)
{
    TCGContext *s = &tcg_ctx;
    int idx;
    TCGLabel *l;

    if (s->nb_labels >= TCG_MAX_LABELS)
        tcg_abort();
    idx = s->nb_labels++;
    l = &s->labels[idx];
    l->has_value = 0;
    l->u.first_reloc = NULL;
    return idx;
}

#include "tcg-target.c"

/* pool based memory allocation */
void *tcg_malloc_internal(TCGContext *s, int size)
{
    TCGPool *p;
    int pool_size;

    if (size > TCG_POOL_CHUNK_SIZE) {
        /* big malloc: insert a new pool (XXX: could optimize) */
        p = qemu_malloc(sizeof(TCGPool) + size);
        p->size = size;
        if (s->pool_current)
            s->pool_current->next = p;
        else
            s->pool_first = p;
        p->next = s->pool_current;
    } else {
        p = s->pool_current;
        if (!p) {
            p = s->pool_first;
            if (!p)
                goto new_pool;
        } else {
            if (!p->next) {
            new_pool:
                pool_size = TCG_POOL_CHUNK_SIZE;
                p = qemu_malloc(sizeof(TCGPool) + pool_size);
                p->size = pool_size;
                p->next = NULL;
                if (s->pool_current) 
                    s->pool_current->next = p;
                else
                    s->pool_first = p;
            } else {
                p = p->next;
            }
        }
    }
    s->pool_current = p;
    s->pool_cur = p->data + size;
    s->pool_end = p->data + p->size;
    return p->data;
}

void tcg_pool_reset(TCGContext *s)
{
    s->pool_cur = s->pool_end = NULL;
    s->pool_current = NULL;
}

/* free all the pool */
void tcg_pool_free(TCGContext *s)
{
    TCGPool *p, *p1;

    for(p = s->pool_first; p != NULL; p = p1) {
        p1 = p->next;
        qemu_free(p);
    }
    s->pool_first = NULL;
    s->pool_cur = s->pool_end = NULL;
}

void tcg_context_init(TCGContext *s)
{
    int op, total_args, n;
    TCGOpDef *def;
    TCGArgConstraint *args_ct;
    int *sorted_args;

    memset(s, 0, sizeof(*s));
    s->temps = s->static_temps;
    s->nb_globals = 0;

    /* Count total number of arguments and allocate the corresponding
       space */
    total_args = 0;
    for(op = 0; op < NB_OPS; op++) {
        def = &tcg_op_defs[op];
        n = def->nb_iargs + def->nb_oargs;
        total_args += n;
    }

    args_ct = qemu_malloc(sizeof(TCGArgConstraint) * total_args);
    sorted_args = qemu_malloc(sizeof(int) * total_args);

    for(op = 0; op < NB_OPS; op++) {
        def = &tcg_op_defs[op];
        def->args_ct = args_ct;
        def->sorted_args = sorted_args;
        n = def->nb_iargs + def->nb_oargs;
        sorted_args += n;
        args_ct += n;
    }

    tcg_target_init(s);
}

void tcg_set_frame(TCGContext *s, int reg,
                   tcg_target_long start, tcg_target_long size)
{
    s->frame_start = start;
    s->frame_end = start + size;
    s->frame_reg = reg;
}

void tcg_set_macro_func(TCGContext *s, TCGMacroFunc *func)
{
    s->macro_func = func;
}

void tcg_func_start(TCGContext *s)
{
    tcg_pool_reset(s);
    s->nb_temps = s->nb_globals;
    s->labels = tcg_malloc(sizeof(TCGLabel) * TCG_MAX_LABELS);
    s->nb_labels = 0;
    s->current_frame_offset = s->frame_start;

    gen_opc_ptr = gen_opc_buf;
    gen_opparam_ptr = gen_opparam_buf;
}

static inline void tcg_temp_alloc(TCGContext *s, int n)
{
    if (n > TCG_MAX_TEMPS)
        tcg_abort();
}

TCGv tcg_global_reg_new(TCGType type, int reg, const char *name)

{
    TCGContext *s = &tcg_ctx;
    TCGTemp *ts;
    int idx;

#if TCG_TARGET_REG_BITS == 32
    if (type != TCG_TYPE_I32)
        tcg_abort();
#endif
    if (tcg_regset_test_reg(s->reserved_regs, reg))
        tcg_abort();
    idx = s->nb_globals;
    tcg_temp_alloc(s, s->nb_globals + 1);
    ts = &s->temps[s->nb_globals];
    ts->base_type = type;
    ts->type = type;
    ts->fixed_reg = 1;
    ts->reg = reg;
    ts->val_type = TEMP_VAL_REG;
    ts->name = name;
    s->nb_globals++;
    tcg_regset_set_reg(s->reserved_regs, reg);

    return MAKE_TCGV(idx);

}

TCGv tcg_global_mem_new(TCGType type, int reg, tcg_target_long offset,
                        const char *name)

{
    TCGContext *s = &tcg_ctx;
    TCGTemp *ts;
    int idx;

    idx = s->nb_globals;
#if TCG_TARGET_REG_BITS == 32
    if (type == TCG_TYPE_I64) {
        char buf[64];
        tcg_temp_alloc(s, s->nb_globals + 1);
        ts = &s->temps[s->nb_globals];
        ts->base_type = type;
        ts->type = TCG_TYPE_I32;
        ts->fixed_reg = 0;
        ts->mem_allocated = 1;
        ts->mem_reg = reg;
#ifdef TCG_TARGET_WORDS_BIGENDIAN
        ts->mem_offset = offset + 4;
#else
        ts->mem_offset = offset;
#endif
        ts->val_type = TEMP_VAL_MEM;
        pstrcpy(buf, sizeof(buf), name);
        pstrcat(buf, sizeof(buf), "_0");
        ts->name = strdup(buf);
        ts++;

        ts->base_type = type;
        ts->type = TCG_TYPE_I32;
        ts->fixed_reg = 0;
        ts->mem_allocated = 1;
        ts->mem_reg = reg;
#ifdef TCG_TARGET_WORDS_BIGENDIAN
        ts->mem_offset = offset;
#else
        ts->mem_offset = offset + 4;
#endif
        ts->val_type = TEMP_VAL_MEM;
        pstrcpy(buf, sizeof(buf), name);
        pstrcat(buf, sizeof(buf), "_1");
        ts->name = strdup(buf);

        s->nb_globals += 2;
    } else
#endif
    {
        tcg_temp_alloc(s, s->nb_globals + 1);
        ts = &s->temps[s->nb_globals];
        ts->base_type = type;
        ts->type = type;
        ts->fixed_reg = 0;
        ts->mem_allocated = 1;
        ts->mem_reg = reg;
        ts->mem_offset = offset;
        ts->val_type = TEMP_VAL_MEM;
        ts->name = name;
        s->nb_globals++;
    }

    return MAKE_TCGV(idx);

}

TCGv tcg_temp_new(TCGType type)

{
    TCGContext *s = &tcg_ctx;
    TCGTemp *ts;
    int idx;

    idx = s->nb_temps;
#if TCG_TARGET_REG_BITS == 32
    if (type == TCG_TYPE_I64) {
        tcg_temp_alloc(s, s->nb_temps + 1);
        ts = &s->temps[s->nb_temps];
        ts->base_type = type;
        ts->type = TCG_TYPE_I32;

        ts->fixed_reg = 0;

        ts->val_type = TEMP_VAL_DEAD;
        ts->mem_allocated = 0;
        ts->name = NULL;
        ts++;
        ts->base_type = TCG_TYPE_I32;
        ts->type = TCG_TYPE_I32;
        ts->val_type = TEMP_VAL_DEAD;

        ts->fixed_reg = 0;

        ts->mem_allocated = 0;
        ts->name = NULL;
        s->nb_temps += 2;
    } else
#endif
    {
        tcg_temp_alloc(s, s->nb_temps + 1);
        ts = &s->temps[s->nb_temps];
        ts->base_type = type;
        ts->type = type;

        ts->fixed_reg = 0;

        ts->val_type = TEMP_VAL_DEAD;
        ts->mem_allocated = 0;
        ts->name = NULL;
        s->nb_temps++;
    }

    return MAKE_TCGV(idx);

}

TCGv tcg_const_i32(int32_t val)

{
    TCGContext *s = &tcg_ctx;
    TCGTemp *ts;
    int idx;

    idx = s->nb_temps;
    tcg_temp_alloc(s, idx + 1);
    ts = &s->temps[idx];
    ts->base_type = ts->type = TCG_TYPE_I32;
    ts->val_type = TEMP_VAL_CONST;
    ts->name = NULL;
    ts->val = val;
    s->nb_temps++;

    return MAKE_TCGV(idx);

}

TCGv tcg_const_i64(int64_t val)

{
    TCGContext *s = &tcg_ctx;
    TCGTemp *ts;
    int idx;

    idx = s->nb_temps;
#if TCG_TARGET_REG_BITS == 32
    tcg_temp_alloc(s, idx + 2);
    ts = &s->temps[idx];
    ts->base_type = TCG_TYPE_I64;
    ts->type = TCG_TYPE_I32;
    ts->val_type = TEMP_VAL_CONST;
    ts->name = NULL;
    ts->val = val;
    ts++;
    ts->base_type = TCG_TYPE_I32;
    ts->type = TCG_TYPE_I32;
    ts->val_type = TEMP_VAL_CONST;
    ts->name = NULL;
    ts->val = val >> 32;
    s->nb_temps += 2;
#else
    tcg_temp_alloc(s, idx + 1);
    ts = &s->temps[idx];
    ts->base_type = ts->type = TCG_TYPE_I64;
    ts->val_type = TEMP_VAL_CONST;
    ts->name = NULL;
    ts->val = val;
    s->nb_temps++;
#endif    

    return MAKE_TCGV(idx);

}

void tcg_register_helper(void *func, const char *name)
{
    TCGContext *s = &tcg_ctx;
    int n;
    if ((s->nb_helpers + 1) > s->allocated_helpers) {
        n = s->allocated_helpers;
        if (n == 0) {
            n = 4;
        } else {
            n *= 2;
        }
        s->helpers = realloc(s->helpers, n * sizeof(TCGHelperInfo));
        s->allocated_helpers = n;
    }
    s->helpers[s->nb_helpers].func = func;
    s->helpers[s->nb_helpers].name = name;
    s->nb_helpers++;
}

const char *tcg_helper_get_name(TCGContext *s, void *func)
{
    int i;

    for(i = 0; i < s->nb_helpers; i++) {
        if (s->helpers[i].func == func)
            return s->helpers[i].name;
    }
    return NULL;
}

static inline TCGType tcg_get_base_type(TCGContext *s, TCGv arg)

{

    return s->temps[GET_TCGV(arg)].base_type;

}

static void tcg_gen_call_internal(TCGContext *s, TCGv func, 

                                  unsigned int flags,

                                  unsigned int nb_rets, const TCGv *rets,
                                  unsigned int nb_params, const TCGv *params)

{
    int i;
    *gen_opc_ptr++ = INDEX_op_call;
    *gen_opparam_ptr++ = (nb_rets << 16) | (nb_params + 1);
    for(i = 0; i < nb_rets; i++) {

        *gen_opparam_ptr++ = GET_TCGV(rets[i]);

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

        *gen_opparam_ptr++ = GET_TCGV(params[i]);

    }

    *gen_opparam_ptr++ = GET_TCGV(func);

    *gen_opparam_ptr++ = flags;
    /* total parameters, needed to go backward in the instruction stream */
    *gen_opparam_ptr++ = 1 + nb_rets + nb_params + 3;
}


#if TCG_TARGET_REG_BITS < 64
/* Note: we convert the 64 bit args to 32 bit */

void tcg_gen_call(TCGContext *s, TCGv func, unsigned int flags,
                  unsigned int nb_rets, const TCGv *rets,
                  unsigned int nb_params, const TCGv *args1)

{

    TCGv ret, *args2, rets_2[2], arg;

    int j, i, call_type;

    if (nb_rets == 1) {
        ret = rets[0];
        if (tcg_get_base_type(s, ret) == TCG_TYPE_I64) {
            nb_rets = 2;
            rets_2[0] = ret;

            rets_2[1] = TCGV_HIGH(ret);

            rets = rets_2;
        }
    }

    args2 = alloca((nb_params * 2) * sizeof(TCGv));

    j = 0;
    call_type = (flags & TCG_CALL_TYPE_MASK);
    for(i = 0; i < nb_params; i++) {
        arg = args1[i];
        if (tcg_get_base_type(s, arg) == TCG_TYPE_I64) {
#ifdef TCG_TARGET_I386
            /* REGPARM case: if the third parameter is 64 bit, it is
               allocated on the stack */
            if (j == 2 && call_type == TCG_CALL_TYPE_REGPARM) {
                call_type = TCG_CALL_TYPE_REGPARM_2;
                flags = (flags & ~TCG_CALL_TYPE_MASK) | call_type;
            }
            args2[j++] = arg;

            args2[j++] = TCGV_HIGH(arg);

#else
#ifdef TCG_TARGET_WORDS_BIGENDIAN

            args2[j++] = TCGV_HIGH(arg);

            args2[j++] = arg;
#else
            args2[j++] = arg;

            args2[j++] = TCGV_HIGH(arg);

#endif
#endif
        } else {
            args2[j++] = arg;
        }
    }
    tcg_gen_call_internal(s, func, flags, 
                          nb_rets, rets, j, args2);
}
#else

void tcg_gen_call(TCGContext *s, TCGv func, unsigned int flags,
                  unsigned int nb_rets, const TCGv *rets,
                  unsigned int nb_params, const TCGv *args1)

{
    tcg_gen_call_internal(s, func, flags, 
                          nb_rets, rets, nb_params, args1);
}
#endif

#if TCG_TARGET_REG_BITS == 32
void tcg_gen_shifti_i64(TCGv ret, TCGv arg1, 

                        int c, int right, int arith)
{
    if (c == 0)
        return;
    if (c >= 32) {
        c -= 32;
        if (right) {
            if (arith) {

                tcg_gen_sari_i32(ret, TCGV_HIGH(arg1), c);
                tcg_gen_sari_i32(TCGV_HIGH(ret), TCGV_HIGH(arg1), 31);

            } else {

                tcg_gen_shri_i32(ret, TCGV_HIGH(arg1), c);
                tcg_gen_movi_i32(TCGV_HIGH(ret), 0);

            }
        } else {

            tcg_gen_shli_i32(TCGV_HIGH(ret), arg1, c);

            tcg_gen_movi_i32(ret, 0);
        }
    } else {

        TCGv t0, t1;

        t0 = tcg_temp_new(TCG_TYPE_I32);
        t1 = tcg_temp_new(TCG_TYPE_I32);
        if (right) {

            tcg_gen_shli_i32(t0, TCGV_HIGH(arg1), 32 - c);

            if (arith)

                tcg_gen_sari_i32(t1, TCGV_HIGH(arg1), c);

            else 

                tcg_gen_shri_i32(t1, TCGV_HIGH(arg1), c);

            tcg_gen_shri_i32(ret, arg1, c); 
            tcg_gen_or_i32(ret, ret, t0);

            tcg_gen_mov_i32(TCGV_HIGH(ret), t1);

        } else {
            tcg_gen_shri_i32(t0, arg1, 32 - c);
            /* Note: ret can be the same as arg1, so we use t1 */
            tcg_gen_shli_i32(t1, arg1, c); 

            tcg_gen_shli_i32(TCGV_HIGH(ret), TCGV_HIGH(arg1), c);
            tcg_gen_or_i32(TCGV_HIGH(ret), TCGV_HIGH(ret), t0);

            tcg_gen_mov_i32(ret, t1);
        }
    }
}

#endif

void tcg_reg_alloc_start(TCGContext *s)
{
    int i;
    TCGTemp *ts;
    for(i = 0; i < s->nb_globals; i++) {
        ts = &s->temps[i];
        if (ts->fixed_reg) {
            ts->val_type = TEMP_VAL_REG;
        } else {
            ts->val_type = TEMP_VAL_MEM;
        }
    }
    for(i = 0; i < TCG_TARGET_NB_REGS; i++) {
        s->reg_to_temp[i] = -1;
    }
}

static char *tcg_get_arg_str_idx(TCGContext *s, char *buf, int buf_size,
                                 int idx)

{
    TCGTemp *ts;

    ts = &s->temps[idx];
    if (idx < s->nb_globals) {
        pstrcpy(buf, buf_size, ts->name);

    } else {
        if (ts->val_type == TEMP_VAL_CONST) {
            snprintf(buf, buf_size, "$0x%" TCG_PRIlx , ts->val);
        } else {

            snprintf(buf, buf_size, "tmp%d", idx - s->nb_globals);

        }
    }
    return buf;
}

char *tcg_get_arg_str(TCGContext *s, char *buf, int buf_size, TCGv arg)
{
    return tcg_get_arg_str_idx(s, buf, buf_size, GET_TCGV(arg));
}

void tcg_dump_ops(TCGContext *s, FILE *outfile)
{
    const uint16_t *opc_ptr;
    const TCGArg *args;
    TCGArg arg;
    int c, i, k, nb_oargs, nb_iargs, nb_cargs;
    const TCGOpDef *def;
    char buf[128];

    opc_ptr = gen_opc_buf;
    args = gen_opparam_buf;
    while (opc_ptr < gen_opc_ptr) {
        c = *opc_ptr++;
        def = &tcg_op_defs[c];
        fprintf(outfile, " %s ", def->name);
        if (c == INDEX_op_call) {
            TCGArg arg;
            /* variable number of arguments */
            arg = *args++;
            nb_oargs = arg >> 16;
            nb_iargs = arg & 0xffff;
            nb_cargs = def->nb_cargs;
        } else if (c == INDEX_op_nopn) {
            /* variable number of arguments */
            nb_cargs = *args;
            nb_oargs = 0;
            nb_iargs = 0;
        } else {
            nb_oargs = def->nb_oargs;
            nb_iargs = def->nb_iargs;
            nb_cargs = def->nb_cargs;
        }

        k = 0;
        for(i = 0; i < nb_oargs; i++) {
            if (k != 0)
                fprintf(outfile, ",");

            fprintf(outfile, "%s",
                    tcg_get_arg_str_idx(s, buf, sizeof(buf), args[k++]));

        }
        for(i = 0; i < nb_iargs; i++) {
            if (k != 0)
                fprintf(outfile, ",");
            /* XXX: dump helper name for call */

            fprintf(outfile, "%s",
                    tcg_get_arg_str_idx(s, buf, sizeof(buf), args[k++]));

        }
        for(i = 0; i < nb_cargs; i++) {
            if (k != 0)
                fprintf(outfile, ",");
            arg = args[k++];
            fprintf(outfile, "$0x%" TCG_PRIlx, arg);
        }
        fprintf(outfile, "\n");
        args += nb_iargs + nb_oargs + nb_cargs;
    }
}

/* we give more priority to constraints with less registers */
static int get_constraint_priority(const TCGOpDef *def, int k)
{
    const TCGArgConstraint *arg_ct;

    int i, n;
    arg_ct = &def->args_ct[k];
    if (arg_ct->ct & TCG_CT_ALIAS) {
        /* an alias is equivalent to a single register */
        n = 1;
    } else {
        if (!(arg_ct->ct & TCG_CT_REG))
            return 0;
        n = 0;
        for(i = 0; i < TCG_TARGET_NB_REGS; i++) {
            if (tcg_regset_test_reg(arg_ct->u.regs, i))
                n++;
        }
    }
    return TCG_TARGET_NB_REGS - n + 1;
}

/* sort from highest priority to lowest */
static void sort_constraints(TCGOpDef *def, int start, int n)
{
    int i, j, p1, p2, tmp;

    for(i = 0; i < n; i++)
        def->sorted_args[start + i] = start + i;
    if (n <= 1)
        return;
    for(i = 0; i < n - 1; i++) {
        for(j = i + 1; j < n; j++) {
            p1 = get_constraint_priority(def, def->sorted_args[start + i]);
            p2 = get_constraint_priority(def, def->sorted_args[start + j]);
            if (p1 < p2) {
                tmp = def->sorted_args[start + i];
                def->sorted_args[start + i] = def->sorted_args[start + j];
                def->sorted_args[start + j] = tmp;
            }
        }
    }
}

void tcg_add_target_add_op_defs(const TCGTargetOpDef *tdefs)
{
    int op;
    TCGOpDef *def;
    const char *ct_str;
    int i, nb_args;

    for(;;) {
        if (tdefs->op < 0)
            break;
        op = tdefs->op;
        assert(op >= 0 && op < NB_OPS);
        def = &tcg_op_defs[op];
        nb_args = def->nb_iargs + def->nb_oargs;
        for(i = 0; i < nb_args; i++) {
            ct_str = tdefs->args_ct_str[i];
            tcg_regset_clear(def->args_ct[i].u.regs);
            def->args_ct[i].ct = 0;
            if (ct_str[0] >= '0' && ct_str[0] <= '9') {
                int oarg;
                oarg = ct_str[0] - '0';
                assert(oarg < def->nb_oargs);
                assert(def->args_ct[oarg].ct & TCG_CT_REG);
                /* TCG_CT_ALIAS is for the output arguments. The input

                   argument is tagged with TCG_CT_IALIAS. */

                def->args_ct[i] = def->args_ct[oarg];

                def->args_ct[oarg].ct = TCG_CT_ALIAS;
                def->args_ct[oarg].alias_index = i;

                def->args_ct[i].ct |= TCG_CT_IALIAS;

                def->args_ct[i].alias_index = oarg;

            } else {
                for(;;) {
                    if (*ct_str == '\0')
                        break;
                    switch(*ct_str) {
                    case 'i':
                        def->args_ct[i].ct |= TCG_CT_CONST;
                        ct_str++;
                        break;
                    default:
                        if (target_parse_constraint(&def->args_ct[i], &ct_str) < 0) {
                            fprintf(stderr, "Invalid constraint '%s' for arg %d of operation '%s'\n",
                                    ct_str, i, def->name);
                            exit(1);
                        }
                    }
                }
            }
        }

        /* sort the constraints (XXX: this is just an heuristic) */
        sort_constraints(def, 0, def->nb_oargs);
        sort_constraints(def, def->nb_oargs, def->nb_iargs);

#if 0
        {
            int i;

            printf("%s: sorted=", def->name);
            for(i = 0; i < def->nb_oargs + def->nb_iargs; i++)
                printf(" %d", def->sorted_args[i]);
            printf("\n");
        }
#endif
        tdefs++;
    }

}

#ifdef USE_LIVENESS_ANALYSIS

/* set a nop for an operation using 'nb_args' */
static inline void tcg_set_nop(TCGContext *s, uint16_t *opc_ptr, 
                               TCGArg *args, int nb_args)
{
    if (nb_args == 0) {
        *opc_ptr = INDEX_op_nop;
    } else {
        *opc_ptr = INDEX_op_nopn;
        args[0] = nb_args;
        args[nb_args - 1] = nb_args;
    }
}

/* liveness analysis: end of basic block: globals are live, temps are dead */
static inline void tcg_la_bb_end(TCGContext *s, uint8_t *dead_temps)
{
    memset(dead_temps, 0, s->nb_globals);
    memset(dead_temps + s->nb_globals, 1, s->nb_temps - s->nb_globals);
}

/* Liveness analysis : update the opc_dead_iargs array to tell if a
   given input arguments is dead. Instructions updating dead
   temporaries are removed. */
void tcg_liveness_analysis(TCGContext *s)
{
    int i, op_index, op, nb_args, nb_iargs, nb_oargs, arg, nb_ops;
    TCGArg *args;
    const TCGOpDef *def;
    uint8_t *dead_temps;
    unsigned int dead_iargs;

    gen_opc_ptr++; /* skip end */

    nb_ops = gen_opc_ptr - gen_opc_buf;

    /* XXX: make it really dynamic */
    s->op_dead_iargs = tcg_malloc(OPC_BUF_SIZE * sizeof(uint16_t));

    dead_temps = tcg_malloc(s->nb_temps);
    memset(dead_temps, 1, s->nb_temps);

    args = gen_opparam_ptr;
    op_index = nb_ops - 1;
    while (op_index >= 0) {
        op = gen_opc_buf[op_index];
        def = &tcg_op_defs[op];
        switch(op) {
        case INDEX_op_call:
            nb_args = args[-1];
            args -= nb_args;
            nb_iargs = args[0] & 0xffff;
            nb_oargs = args[0] >> 16;
            args++;

            /* output args are dead */
            for(i = 0; i < nb_oargs; i++) {
                arg = args[i];
                dead_temps[arg] = 1;
            }

            /* globals are live (they may be used by the call) */
            memset(dead_temps, 0, s->nb_globals);

            /* input args are live */
            dead_iargs = 0;
            for(i = 0; i < nb_iargs; i++) {
                arg = args[i + nb_oargs];
                if (dead_temps[arg]) {
                    dead_iargs |= (1 << i);
                }
                dead_temps[arg] = 0;
            }
            s->op_dead_iargs[op_index] = dead_iargs;
            args--;
            break;
        case INDEX_op_set_label:
            args--;
            /* mark end of basic block */
            tcg_la_bb_end(s, dead_temps);
            break;
        case INDEX_op_nopn:
            nb_args = args[-1];
            args -= nb_args;
            break;

        case INDEX_op_discard:
            args--;
            /* mark the temporary as dead */
            dead_temps[args[0]] = 1;
            break;

        case INDEX_op_macro_2:
            {
                int dead_args[2], macro_id;
                int saved_op_index, saved_arg_index;
                int macro_op_index, macro_arg_index;
                int macro_end_op_index, macro_end_arg_index;
                int last_nb_temps;

                nb_args = 3;
                args -= nb_args;
                dead_args[0] = dead_temps[args[0]];
                dead_args[1] = dead_temps[args[1]];
                macro_id = args[2];

                /* call the macro function which generate code
                   depending on the live outputs */
                saved_op_index = op_index;
                saved_arg_index = args - gen_opparam_buf;

                /* add a macro start instruction */
                *gen_opc_ptr++ = INDEX_op_macro_start;
                *gen_opparam_ptr++ = saved_op_index;
                *gen_opparam_ptr++ = saved_arg_index;

                macro_op_index = gen_opc_ptr - gen_opc_buf;
                macro_arg_index = gen_opparam_ptr -  gen_opparam_buf;

                last_nb_temps = s->nb_temps;

                s->macro_func(s, macro_id, dead_args);

                /* realloc temp info (XXX: make it faster) */
                if (s->nb_temps > last_nb_temps) {
                    uint8_t *new_dead_temps;

                    new_dead_temps = tcg_malloc(s->nb_temps);
                    memcpy(new_dead_temps, dead_temps, last_nb_temps);
                    memset(new_dead_temps + last_nb_temps, 1, 
                           s->nb_temps - last_nb_temps);
                    dead_temps = new_dead_temps;
                }

                macro_end_op_index = gen_opc_ptr - gen_opc_buf;
                macro_end_arg_index = gen_opparam_ptr - gen_opparam_buf;

                /* end of macro: add a goto to the next instruction */
                *gen_opc_ptr++ = INDEX_op_macro_end;
                *gen_opparam_ptr++ = op_index + 1;
                *gen_opparam_ptr++ = saved_arg_index + nb_args;

                /* modify the macro operation to be a macro_goto */
                gen_opc_buf[op_index] = INDEX_op_macro_goto;
                args[0] = macro_op_index;
                args[1] = macro_arg_index;
                args[2] = 0; /* dummy third arg to match the 
                                macro parameters */

                /* set the next instruction to the end of the macro */
                op_index = macro_end_op_index;
                args = macro_end_arg_index + gen_opparam_buf;
            }
            break;
        case INDEX_op_macro_start:
            args -= 2;
            op_index = args[0];
            args = gen_opparam_buf + args[1];
            break;
        case INDEX_op_macro_goto:
        case INDEX_op_macro_end:
            tcg_abort(); /* should never happen in liveness analysis */
        case INDEX_op_end:
            break;
            /* XXX: optimize by hardcoding common cases (e.g. triadic ops) */
        default:
            if (op > INDEX_op_end) {
                args -= def->nb_args;
                nb_iargs = def->nb_iargs;
                nb_oargs = def->nb_oargs;

                /* Test if the operation can be removed because all