tcg-target.c

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/*
 * 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.
 */
const char *tcg_target_reg_names[TCG_TARGET_NB_REGS] = {
    "%rax",
    "%rcx",
    "%rdx",
    "%rbx",
    "%rsp",
    "%rbp",
    "%rsi",
    "%rdi",
    "%r8",
    "%r9",
    "%r10",
    "%r11",
    "%r12",
    "%r13",
    "%r14",
    "%r15",
};

int tcg_target_reg_alloc_order[] = {
    TCG_REG_RDI,
    TCG_REG_RSI,
    TCG_REG_RDX,
    TCG_REG_RCX,
    TCG_REG_R8,
    TCG_REG_R9,
    TCG_REG_RAX,
    TCG_REG_R10,
    TCG_REG_R11,

    TCG_REG_RBP,
    TCG_REG_RBX,
    TCG_REG_R12,
    TCG_REG_R13,
    TCG_REG_R14,
    TCG_REG_R15,
};

const int tcg_target_call_iarg_regs[6] = { 
    TCG_REG_RDI,
    TCG_REG_RSI,
    TCG_REG_RDX,
    TCG_REG_RCX,
    TCG_REG_R8,
    TCG_REG_R9,
};

const int tcg_target_call_oarg_regs[2] = { 
    TCG_REG_RAX, 
    TCG_REG_RDX 
};

static uint8_t *tb_ret_addr;

static void patch_reloc(uint8_t *code_ptr, int type, 
                        tcg_target_long value, tcg_target_long addend)
{
    value += addend;
    switch(type) {
    case R_X86_64_32:
        if (value != (uint32_t)value)
            tcg_abort();
        *(uint32_t *)code_ptr = value;
        break;
    case R_X86_64_32S:
        if (value != (int32_t)value)
            tcg_abort();
        *(uint32_t *)code_ptr = value;
        break;
    case R_386_PC32:
        value -= (long)code_ptr;
        if (value != (int32_t)value)
            tcg_abort();
        *(uint32_t *)code_ptr = value;
        break;
    default:
        tcg_abort();
    }
}

/* maximum number of register used for input function arguments */
static inline int tcg_target_get_call_iarg_regs_count(int flags)
{
    return 6;
}

/* parse target specific constraints */
int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str)
{
    const char *ct_str;

    ct_str = *pct_str;
    switch(ct_str[0]) {
    case 'a':
        ct->ct |= TCG_CT_REG;
        tcg_regset_set_reg(ct->u.regs, TCG_REG_RAX);
        break;
    case 'b':
        ct->ct |= TCG_CT_REG;
        tcg_regset_set_reg(ct->u.regs, TCG_REG_RBX);
        break;
    case 'c':
        ct->ct |= TCG_CT_REG;
        tcg_regset_set_reg(ct->u.regs, TCG_REG_RCX);
        break;
    case 'd':
        ct->ct |= TCG_CT_REG;
        tcg_regset_set_reg(ct->u.regs, TCG_REG_RDX);
        break;
    case 'S':
        ct->ct |= TCG_CT_REG;
        tcg_regset_set_reg(ct->u.regs, TCG_REG_RSI);
        break;
    case 'D':
        ct->ct |= TCG_CT_REG;
        tcg_regset_set_reg(ct->u.regs, TCG_REG_RDI);
        break;
    case 'q':
        ct->ct |= TCG_CT_REG;
        tcg_regset_set32(ct->u.regs, 0, 0xf);
        break;
    case 'r':
        ct->ct |= TCG_CT_REG;
        tcg_regset_set32(ct->u.regs, 0, 0xffff);
        break;
    case 'L': /* qemu_ld/st constraint */
        ct->ct |= TCG_CT_REG;
        tcg_regset_set32(ct->u.regs, 0, 0xffff);
        tcg_regset_reset_reg(ct->u.regs, TCG_REG_RSI);
        tcg_regset_reset_reg(ct->u.regs, TCG_REG_RDI);
        break;
    case 'e':
        ct->ct |= TCG_CT_CONST_S32;
        break;
    case 'Z':
        ct->ct |= TCG_CT_CONST_U32;
        break;
    default:
        return -1;
    }
    ct_str++;
    *pct_str = ct_str;
    return 0;
}

/* test if a constant matches the constraint */
static inline int tcg_target_const_match(tcg_target_long val,
                                         const TCGArgConstraint *arg_ct)
{
    int ct;
    ct = arg_ct->ct;
    if (ct & TCG_CT_CONST)
        return 1;
    else if ((ct & TCG_CT_CONST_S32) && val == (int32_t)val)
        return 1;
    else if ((ct & TCG_CT_CONST_U32) && val == (uint32_t)val)
        return 1;
    else
        return 0;
}

#define ARITH_ADD 0
#define ARITH_OR  1
#define ARITH_ADC 2
#define ARITH_SBB 3
#define ARITH_AND 4
#define ARITH_SUB 5
#define ARITH_XOR 6
#define ARITH_CMP 7

#define SHIFT_SHL 4
#define SHIFT_SHR 5
#define SHIFT_SAR 7

#define JCC_JMP (-1)
#define JCC_JO  0x0
#define JCC_JNO 0x1
#define JCC_JB  0x2
#define JCC_JAE 0x3
#define JCC_JE  0x4
#define JCC_JNE 0x5
#define JCC_JBE 0x6
#define JCC_JA  0x7
#define JCC_JS  0x8
#define JCC_JNS 0x9
#define JCC_JP  0xa
#define JCC_JNP 0xb
#define JCC_JL  0xc
#define JCC_JGE 0xd
#define JCC_JLE 0xe
#define JCC_JG  0xf

#define P_EXT   0x100 /* 0x0f opcode prefix */
#define P_REXW  0x200 /* set rex.w = 1 */
#define P_REXB  0x400 /* force rex use for byte registers */
                                  
static const uint8_t tcg_cond_to_jcc[10] = {
    [TCG_COND_EQ] = JCC_JE,
    [TCG_COND_NE] = JCC_JNE,
    [TCG_COND_LT] = JCC_JL,
    [TCG_COND_GE] = JCC_JGE,
    [TCG_COND_LE] = JCC_JLE,
    [TCG_COND_GT] = JCC_JG,
    [TCG_COND_LTU] = JCC_JB,
    [TCG_COND_GEU] = JCC_JAE,
    [TCG_COND_LEU] = JCC_JBE,
    [TCG_COND_GTU] = JCC_JA,
};

static inline void tcg_out_opc(TCGContext *s, int opc, int r, int rm, int x)
{
    int rex;
    rex = ((opc >> 6) & 0x8) | ((r >> 1) & 0x4) | 
        ((x >> 2) & 2) | ((rm >> 3) & 1);
    if (rex || (opc & P_REXB)) {
        tcg_out8(s, rex | 0x40);
    }
    if (opc & P_EXT)
        tcg_out8(s, 0x0f);
    tcg_out8(s, opc);
}

static inline void tcg_out_modrm(TCGContext *s, int opc, int r, int rm)
{
    tcg_out_opc(s, opc, r, rm, 0);
    tcg_out8(s, 0xc0 | ((r & 7) << 3) | (rm & 7));
}

/* rm < 0 means no register index plus (-rm - 1 immediate bytes) */
static inline void tcg_out_modrm_offset(TCGContext *s, int opc, int r, int rm, 
                                        tcg_target_long offset)
{
    if (rm < 0) {
        tcg_target_long val;
        tcg_out_opc(s, opc, r, 0, 0);
        val = offset - ((tcg_target_long)s->code_ptr + 5 + (-rm - 1));
        if (val == (int32_t)val) {
            /* eip relative */
            tcg_out8(s, 0x05 | ((r & 7) << 3));
            tcg_out32(s, val);
        } else if (offset == (int32_t)offset) {
            tcg_out8(s, 0x04 | ((r & 7) << 3));
            tcg_out8(s, 0x25); /* sib */
            tcg_out32(s, offset);
        } else {
            tcg_abort();
        }
    } else if (offset == 0 && (rm & 7) != TCG_REG_RBP) {
        tcg_out_opc(s, opc, r, rm, 0);
        if ((rm & 7) == TCG_REG_RSP) {
            tcg_out8(s, 0x04 | ((r & 7) << 3));
            tcg_out8(s, 0x24);
        } else {
            tcg_out8(s, 0x00 | ((r & 7) << 3) | (rm & 7));
        }
    } else if ((int8_t)offset == offset) {
        tcg_out_opc(s, opc, r, rm, 0);
        if ((rm & 7) == TCG_REG_RSP) {
            tcg_out8(s, 0x44 | ((r & 7) << 3));
            tcg_out8(s, 0x24);
        } else {
            tcg_out8(s, 0x40 | ((r & 7) << 3) | (rm & 7));
        }
        tcg_out8(s, offset);
    } else {
        tcg_out_opc(s, opc, r, rm, 0);
        if ((rm & 7) == TCG_REG_RSP) {
            tcg_out8(s, 0x84 | ((r & 7) << 3));
            tcg_out8(s, 0x24);
        } else {
            tcg_out8(s, 0x80 | ((r & 7) << 3) | (rm & 7));
        }
        tcg_out32(s, offset);
    }
}

#if defined(CONFIG_SOFTMMU)
/* XXX: incomplete. index must be different from ESP */
static void tcg_out_modrm_offset2(TCGContext *s, int opc, int r, int rm, 
                                  int index, int shift,
                                  tcg_target_long offset)
{
    int mod;
    if (rm == -1)
        tcg_abort();
    if (offset == 0 && (rm & 7) != TCG_REG_RBP) {
        mod = 0;
    } else if (offset == (int8_t)offset) {
        mod = 0x40;
    } else if (offset == (int32_t)offset) {
        mod = 0x80;
    } else {
        tcg_abort();
    }
    if (index == -1) {
        tcg_out_opc(s, opc, r, rm, 0);
        if ((rm & 7) == TCG_REG_RSP) {
            tcg_out8(s, mod | ((r & 7) << 3) | 0x04);
            tcg_out8(s, 0x04 | (rm & 7));
        } else {
            tcg_out8(s, mod | ((r & 7) << 3) | (rm & 7));
        }
    } else {
        tcg_out_opc(s, opc, r, rm, index);
        tcg_out8(s, mod | ((r & 7) << 3) | 0x04);
        tcg_out8(s, (shift << 6) | ((index & 7) << 3) | (rm & 7));
    }
    if (mod == 0x40) {
        tcg_out8(s, offset);
    } else if (mod == 0x80) {
        tcg_out32(s, offset);
    }
}
#endif

static inline void tcg_out_mov(TCGContext *s, int ret, int arg)
{
    tcg_out_modrm(s, 0x8b | P_REXW, ret, arg);
}

static inline void tcg_out_movi(TCGContext *s, TCGType type, 
                                int ret, tcg_target_long arg)
{
    if (arg == 0) {
        tcg_out_modrm(s, 0x01 | (ARITH_XOR << 3), ret, ret); /* xor r0,r0 */
    } else if (arg == (uint32_t)arg || type == TCG_TYPE_I32) {
        tcg_out_opc(s, 0xb8 + (ret & 7), 0, ret, 0);
        tcg_out32(s, arg);
    } else if (arg == (int32_t)arg) {
        tcg_out_modrm(s, 0xc7 | P_REXW, 0, ret);
        tcg_out32(s, arg);
    } else {
        tcg_out_opc(s, (0xb8 + (ret & 7)) | P_REXW, 0, ret, 0);
        tcg_out32(s, arg);
        tcg_out32(s, arg >> 32);
    }
}

static inline void tcg_out_ld(TCGContext *s, TCGType type, int ret,
                              int arg1, tcg_target_long arg2)
{
    if (type == TCG_TYPE_I32)
        tcg_out_modrm_offset(s, 0x8b, ret, arg1, arg2); /* movl */
    else
        tcg_out_modrm_offset(s, 0x8b | P_REXW, ret, arg1, arg2); /* movq */
}

static inline void tcg_out_st(TCGContext *s, TCGType type, int arg,
                              int arg1, tcg_target_long arg2)
{
    if (type == TCG_TYPE_I32)
        tcg_out_modrm_offset(s, 0x89, arg, arg1, arg2); /* movl */
    else
        tcg_out_modrm_offset(s, 0x89 | P_REXW, arg, arg1, arg2); /* movq */
}

static inline void tgen_arithi32(TCGContext *s, int c, int r0, int32_t val)
{
    if (val == (int8_t)val) {
        tcg_out_modrm(s, 0x83, c, r0);
        tcg_out8(s, val);
    } else {
        tcg_out_modrm(s, 0x81, c, r0);
        tcg_out32(s, val);
    }
}

static inline void tgen_arithi64(TCGContext *s, int c, int r0, int64_t val)
{
    if (val == (int8_t)val) {
        tcg_out_modrm(s, 0x83 | P_REXW, c, r0);
        tcg_out8(s, val);
    } else if (val == (int32_t)val) {
        tcg_out_modrm(s, 0x81 | P_REXW, c, r0);
        tcg_out32(s, val);
    } else if (c == ARITH_AND && val == (uint32_t)val) {
        tcg_out_modrm(s, 0x81, c, r0);
        tcg_out32(s, val);
    } else {
        tcg_abort();
    }
}

void tcg_out_addi(TCGContext *s, int reg, tcg_target_long val)
{
    if (val != 0)
        tgen_arithi64(s, ARITH_ADD, reg, val);
}

static void tcg_out_jxx(TCGContext *s, int opc, int label_index)
{
    int32_t val, val1;
    TCGLabel *l = &s->labels[label_index];
    
    if (l->has_value) {
        val = l->u.value - (tcg_target_long)s->code_ptr;
        val1 = val - 2;
        if ((int8_t)val1 == val1) {
            if (opc == -1)
                tcg_out8(s, 0xeb);
            else
                tcg_out8(s, 0x70 + opc);
            tcg_out8(s, val1);
        } else {
            if (opc == -1) {
                tcg_out8(s, 0xe9);
                tcg_out32(s, val - 5);
            } else {
                tcg_out8(s, 0x0f);
                tcg_out8(s, 0x80 + opc);
                tcg_out32(s, val - 6);