md-abi.cpp

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/* src/vm/jit/arm/md-abi.cpp - functions for arm ABI

   Copyright (C) 1996-2013
   CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO

   This file is part of CACAO.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.

*/


#include "config.h"
#include "vm/types.hpp"

#include "vm/jit/arm/md-abi.hpp"

#include "vm/descriptor.hpp"
#include "vm/method.hpp"
#include "vm/global.hpp"

#include "vm/jit/abi.hpp"
#include "vm/jit/code.hpp"
#include "vm/jit/codegen-common.hpp" // for PACK_REGS

/* register descripton array **************************************************/

s4 nregdescint[] = {
    REG_ARG, REG_ARG, REG_ARG, REG_ARG, REG_SAV, REG_SAV, REG_SAV, REG_SAV,
    REG_SAV, REG_RES, REG_RES, REG_RES, REG_RES, REG_RES, REG_RES, REG_RES,
    REG_END
};

const char *abi_registers_integer_name[] = {
    "a1", "a2", "a3", "a4", "v1", "v2", "v3", "v4",
    "v5", "t3", "t1", "t2", "ip", "sp", "lr", "pc",
};

const s4 abi_registers_integer_argument[] = {
    0,  /* a0 */
    1,  /* a1 */
    2,  /* a2 */
    3,  /* a3 */
    REG_SPLIT,
};

const s4 abi_registers_integer_saved[] = {
    4,  /* s0 */
    5,  /* s1 */
    6,  /* s2 */
    7,  /* s3 */
    8,  /* s4 */
};

const s4 abi_registers_integer_temporary[] = {
    -1,
};


#if defined(ENABLE_SOFTFLOAT)
s4 nregdescfloat[] = {
    REG_RES, REG_RES, REG_RES, REG_RES,
    REG_RES, REG_RES, REG_RES, REG_RES,
    REG_END
};
#else
#if !defined(__ARMHF__)
s4 nregdescfloat[] = {
    REG_TMP, REG_TMP, REG_TMP, REG_TMP,
    REG_TMP, REG_TMP, REG_RES, REG_RES,
    REG_END
};
#else
s4 nregdescfloat[] = {
    REG_ARG, REG_ARG, REG_ARG, REG_ARG, REG_ARG, REG_ARG, REG_RES, REG_RES,
    REG_SAV, REG_SAV, REG_SAV, REG_SAV, REG_SAV, REG_SAV, REG_SAV, REG_SAV,
    REG_END
};
#endif
#endif /* defined(ENABLE_SOFTFLOAT) */

const s4 abi_registers_float_argument[] = {
#if defined(__ARMHF__)
    0, 1, 2, 3, 4, 5, 6, 7,
#endif
    -1,
};

const s4 abi_registers_float_saved[] = {
#if defined(__ARMHF__)
    8, 9, 10, 11, 12, 13, 14, 15,
#endif
    -1,
};

const s4 abi_registers_float_temporary[] = {
#if defined(__ARMHF__) || defined(ENABLE_SOFTFLOAT)
    -1,
#else
    0,  /* ft0 */
    1,  /* ft1 */
    2,  /* ft2 */
    3,  /* ft3 */
    4,  /* ft4 */
    5,  /* ft5 */
#endif
};


/* md_param_alloc **************************************************************

   Allocate Arguments to Stackslots according the Calling Conventions

   --- in:
   md->paramcount:           Number of arguments for this method
   md->paramtypes[].type:    Argument types

   --- out:
   md->params[].inmemory:    Argument spilled on stack
   md->params[].regoff:      Stack offset or rd->arg[int|flt]regs index
   md->memuse:               Stackslots needed for argument spilling
   md->argintreguse:         max number of integer arguments used
   md->argfltreguse:         max number of float arguments used

*******************************************************************************/

void md_param_alloc(methoddesc *md)
{
    paramdesc *pd;
    s4         i;
    s4         reguse, freguse;
    s4         stacksize;

    /* set default values */

    reguse    = 0;
    freguse   = 0;
    stacksize = 0;

    /* get params field of methoddesc */

    pd = md->params;

    for (i = 0; i < md->paramcount; i++, pd++) {
        switch (md->paramtypes[i].type) {
        case TYPE_INT:
        case TYPE_ADR:
#if !defined(__ARMHF__)
        case TYPE_FLT:
#endif
            if (reguse < INT_ARG_CNT) {
                pd->inmemory = false;
                pd->index    = reguse;
                pd->regoff   = abi_registers_integer_argument[reguse];
                reguse++;
            }
            else {
                pd->inmemory = true;
                pd->index    = stacksize;
                pd->regoff   = stacksize * 8;
                stacksize++;
            }
            break;

        case TYPE_LNG:
#if !defined(__ARMHF__)
        case TYPE_DBL:
#endif
            /* interally we use the EABI */

            ALIGN_2(reguse);

            if (reguse < INT_ARG_CNT) {
                pd->inmemory = false;
#if defined(__ARMEL__)
                pd->index    = PACK_REGS(reguse, reguse + 1);
                pd->regoff   =
                    PACK_REGS(abi_registers_integer_argument[reguse],
                              abi_registers_integer_argument[reguse + 1]);
#else
                pd->index    = PACK_REGS(reguse + 1, reguse);
                pd->regoff   =
                    PACK_REGS(abi_registers_integer_argument[reguse + 1],
                              abi_registers_integer_argument[reguse]);
#endif
                reguse += 2;
            }
            else {

                /*ALIGN_2(stacksize);*/

                pd->inmemory  = true;
                pd->index     = stacksize;
                pd->regoff    = stacksize * 8;
                /*stacksize    += 2;*/
                stacksize++;
            }
            break;

#if defined(__ARMHF__)
        case TYPE_FLT:
        case TYPE_DBL:
            if (freguse < FLT_ARG_CNT) {
                pd->inmemory = false;
                pd->index    = freguse;
                pd->regoff   = abi_registers_float_argument[freguse];
                freguse++;
            }
            else {
                pd->inmemory = true;
                pd->index    = stacksize;
                pd->regoff   = stacksize * 8;
                stacksize++;
            }
            break;
#endif
        }
    }

    /* Since R0/R1 (==A0/A1) are used for passing return values, this
       argument register usage has to be regarded, too. */

    if (md->returntype.type != TYPE_VOID
#if defined(__ARMHF__)
            && !IS_FLT_DBL_TYPE(md->returntype.type)
#endif
    )
    {
        if (!IS_2_WORD_TYPE(md->returntype.type)) {
            if (reguse < 1)
                reguse = 1;
        }
        else {
            if (reguse < 2)
                reguse = 2;
        }
    }
#if defined(__ARMHF__)
    else if (IS_FLT_DBL_TYPE(md->returntype.type))
        if (freguse < 1)
            freguse = 1;
#endif

    /* fill register and stack usage */

    md->argintreguse = reguse;
    md->argfltreguse = freguse;
    md->memuse       = stacksize;
}


/* md_param_alloc_native *******************************************************

   Pre-allocate arguments according the native ABI.

*******************************************************************************/

void md_param_alloc_native(methoddesc *md)
{
    paramdesc *pd;
    s4         i;
    s4         reguse, freguse;
    s4         stacksize;
    s1 sregused[8]; /* 1 = full, 0 = half free */
    bool backfill;

    /* set default values */

    reguse    = 0;
    freguse   = 0;
    stacksize = 0;
    backfill  = true;

    /* get params field of methoddesc */

    pd = md->params;

    for (i = 0; i < md->paramcount; i++, pd++) {
#if defined(__ARMHF__)
        if (IS_FLT_DBL_TYPE(md->paramtypes[i].type)) {
            bool found = false;
            do {
                /* Try to find free VFP register first. */
                /* If it fails, use the normal path below. */
                if (IS_2_WORD_TYPE(md->paramtypes[i].type)) {
                    if (freguse >= 8)
                        break;
                    pd->inmemory = false;
                    pd->index    = -1;
                    pd->regoff   = abi_registers_float_argument[freguse];
                    sregused[freguse] = 1;
                    freguse++;
                }
                else {
                    int i;
                    if (backfill) {
                        for (i=0; i<freguse; i++)
                            if (!sregused[i])
                                break;
                    }
                    else
                        i = freguse;
                    if (i<freguse) {
                        pd->regoff   = abi_registers_float_argument[i] + BACKFILL_OFFSET;
                        sregused[i] = 1;
                    }
                    else {
                        if (freguse >= 8)
                            break;
                        /* no backfill space found */
                        pd->regoff   = abi_registers_float_argument[freguse];
                        sregused[freguse] = 0;
                        freguse++;
                    }
                    pd->inmemory = false;
                    pd->index    = -1;
                }
                found = true;
            } while (0);
            if (found)
                continue;
            backfill = false;
        }
#endif

        switch (md->paramtypes[i].type) {
        case TYPE_INT:
        case TYPE_ADR:
        case TYPE_FLT:
            if (reguse < INT_ARG_CNT
#if defined(__ARMHF__)
                && md->paramtypes[i].type != TYPE_FLT
#endif
               ) {
                pd->inmemory = false;
                pd->index    = -1;
                pd->regoff   = abi_registers_integer_argument[reguse];
                reguse++;
            }
            else {
                pd->inmemory = true;
                pd->index    = -1;
                pd->regoff   = stacksize * 4;
                stacksize++;
            }
            break;

        case TYPE_LNG:
        case TYPE_DBL:
            if (reguse < (INT_ARG_CNT - 1)
#if defined(__ARMHF__)
                && md->paramtypes[i].type != TYPE_DBL
#endif
                ) {
#if defined(__ARM_EABI__)
                ALIGN_2(reguse);
#endif
                pd->inmemory = false;
#if defined(__ARMEL__)
                pd->index    = -1;
                pd->regoff   =
                    PACK_REGS(abi_registers_integer_argument[reguse],
                              abi_registers_integer_argument[reguse + 1]);
#else
                pd->index    = -1;
                pd->regoff   =
                    PACK_REGS(abi_registers_integer_argument[reguse + 1],
                              abi_registers_integer_argument[reguse]);
#endif
                reguse += 2;
            }
#if !defined(__ARM_EABI__)
            else if (reguse < INT_ARG_CNT) {
                pd->inmemory = false;
# if defined(__ARMEL__)
                pd->index    = -1;
                pd->regoff   =
                    PACK_REGS(abi_registers_integer_argument[reguse],
                              abi_registers_integer_argument[INT_ARG_CNT]);
# else
                pd->index    = -1;
                pd->regoff   =
                    PACK_REGS(abi_registers_integer_argument[INT_ARG_CNT],
                              abi_registers_integer_argument[reguse]);
# endif
                reguse++;
                stacksize++;
            }
#endif
            else {
#if defined(__ARM_EABI__)
                ALIGN_2(stacksize);
#endif
                pd->inmemory  = true;
                pd->index     = -1;
                pd->regoff    = stacksize * 4;
#if defined(__ARMHF__)
                if (md->paramtypes[i].type != TYPE_DBL)
#endif
                    reguse        = INT_ARG_CNT;
                stacksize    += 2;
            }
            break;
        }
    }

    /* Since R0/R1 (==A0/A1) are used for passing return values, this
       argument register usage has to be regarded, too. */

    if (md->returntype.type != TYPE_VOID
#if defined(__ARMHF__)
            && !IS_FLT_DBL_TYPE(md->returntype.type)
#endif
    )
    {
        if (!IS_2_WORD_TYPE(md->returntype.type)) {
            if (reguse < 1)
                reguse = 1;
        }
        else {
            if (reguse < 2)
                reguse = 2;
        }
    }
#if defined(__ARMHF__)
    else if (IS_FLT_DBL_TYPE(md->returntype.type))
        if (freguse < 1)
            freguse = 1;
#endif

    /* fill register and stack usage */

    md->argintreguse = reguse;
    md->argfltreguse = freguse;
    md->memuse       = stacksize;
}


/* md_return_alloc *************************************************************

   Precolor the Java Stackelement containing the Return Value, if possible.

   --- in
   m:                       Methodinfo of current method
   return_type:             Return Type of the Method (TYPE_INT.. TYPE_ADR)
                            TYPE_VOID is not allowed!
   stackslot:               Java Stackslot to contain the Return Value

   --- out
   if precoloring was possible:
   VAR(stackslot->varnum)->flags = PREALLOC
   VAR(stackslot->varnum)->vv.regoff = [REG_RESULT, (REG_RESULT2/REG_RESULT), REG_FRESULT]
   rd->arg[flt|int]reguse   set to a value according the register usage

*******************************************************************************/

void md_return_alloc(jitdata *jd, stackelement_t *stackslot)
{
    methodinfo   *m;
    codeinfo     *code;
    registerdata *rd;
    methoddesc   *md;

    /* get required compiler data */

    m    = jd->m;
    code = jd->code;
    rd   = jd->rd;

    md = m->parseddesc;

    /* In Leafmethods Local Vars holding parameters are precolored to
       their argument register -> so leafmethods with paramcount > 0
       could already use R0 == a00! */

    if (!code_is_leafmethod(code) || (md->paramcount == 0)) {
        /* Only precolor the stackslot, if it is not a SAVEDVAR <->
           has not to survive method invokations. */

        if (!(stackslot->flags & SAVEDVAR)) {
#if !defined(ENABLE_SOFTFLOAT)
            /* Stackelements containing float or double values
               (TYPE_FLT | TYPE_DBL) cannot be precolored, because we
               use integer register to pass return values. (floats:
               R0, doubles: R0/R1) */

            if (!IS_FLT_DBL_TYPE(md->returntype.type)) {
#endif

                VAR(stackslot->varnum)->flags = PREALLOC;

                if (!IS_2_WORD_TYPE(md->returntype.type)) {
                    if (rd->argintreguse < 1)
                        rd->argintreguse = 1;

                    VAR(stackslot->varnum)->vv.regoff = REG_RESULT;
                }
                else {
                    if (rd->argintreguse < 2)
                        rd->argintreguse = 2;

                    VAR(stackslot->varnum)->vv.regoff = REG_RESULT_PACKED;
                }

#if !defined(ENABLE_SOFTFLOAT)
            }
#if defined(__ARMHF__)
            else {
                VAR(stackslot->varnum)->flags = PREALLOC;

                if (rd->argfltreguse < 1)
                    rd->argfltreguse = 1;

                VAR(stackslot->varnum)->vv.regoff = REG_FRESULT;
            }
#endif
#endif
        }
    }
}


/*
 * These are local overrides for various environment variables in Emacs.
 * Please do not remove this and leave it at the end of the file, where
 * Emacs will automagically detect them.
 * ---------------------------------------------------------------------
 * Local variables:
 * mode: c++
 * indent-tabs-mode: t
 * c-basic-offset: 4
 * tab-width: 4
 * End:
 * vim:noexpandtab:sw=4:ts=4:
 */