MWCC/compiler_and_linker/unsorted/Registers.c

#include "compiler/Registers.h"
#include "compiler/RegisterInfo.h"
#include "compiler/CParser.h"
#include "compiler/PCode.h"
#include "compiler/CompilerTools.h"
#include "compiler/objects.h"

int used_virtual_registers[RegClassMax];
int used_nonvolatile_registers[RegClassMax];
int assignable_registers[RegClassMax];
int n_real_registers[RegClassMax];
int n_scratch_registers[RegClassMax];
int scratch_registers[RegClassMax][RegisterMax];
int n_nonvolatile_registers[RegClassMax];
int nonvolatile_registers[RegClassMax][RegisterMax];
UInt8 reg_state[RegClassMax][RegisterMax];
int first_temporary_register[RegClassMax];
int last_temporary_register[RegClassMax];
char *register_class_name[RegClassMax];
char *register_class_format[RegClassMax];
int coloring;
int optimizing;

typedef struct ModifiedRegisters {
    struct ModifiedRegisters *next;
    Object *obj;
    UInt32 mask[RegClassMax];
} ModifiedRegisters;
static ModifiedRegisters *mod_regs_table[128];

void init_registers(void) {
    RegClass rclass;
    int j;

    for (rclass = 0; rclass < RegClassMax; rclass++) {
        for (j = 0; j < RegisterMax; j++)
            reg_state[rclass][j] = RegState0;
    }

    for (rclass = 0; rclass < RegClassMax; rclass++)
        used_nonvolatile_registers[rclass] = 0;

    optimizing = 1;

    init_target_registers();
    for (rclass = 0; rclass < RegClassMax; rclass++)
        used_virtual_registers[rclass] = n_real_registers[rclass];

    coloring = 1;
}

void assign_register_to_variable(Object *obj, RegClass rclass) {
    VarInfo *vi;
    short reg;

    vi = Registers_GetVarInfo(obj);
    if (optimizing) {
        reg = used_virtual_registers[rclass]++;
    } else {
        reg = obtain_nonvolatile_register(rclass);
        retain_register(obj, rclass, reg);
    }

    vi->flags |= VarInfoFlag2;
    vi->rclass = rclass;
    vi->reg = reg;
}

void retain_register_for_argument(Object *obj, RegClass rclass, short reg) {
    VarInfo *vi = obj->u.var.info;
    reg_state[rclass][reg] = RegState1;
    vi->flags |= VarInfoFlag2;
    vi->rclass = rclass;
    vi->reg = reg;
}

int available_registers(RegClass rclass) {
    int i;
    int count = 0;

    for (i = 0; i < n_real_registers[rclass]; i++) {
        if (reg_state[rclass][i] == RegState0)
            count++;
    }

    return count;
}

UInt32 volatile_registers(RegClass rclass) {
    UInt32 mask = 0;
    int i;
    int reg;

    for (i = 0; i < n_scratch_registers[rclass]; i++) {
        reg = scratch_registers[rclass][i];
        if (reg_state[rclass][reg] == RegState0)
            mask |= 1 << reg;
    }

    return mask;
}

short obtain_nonvolatile_register(RegClass rclass) {
    int best = -1;

    while (used_nonvolatile_registers[rclass] < n_nonvolatile_registers[rclass]) {
        int tmp = nonvolatile_registers[rclass][used_nonvolatile_registers[rclass]++];
        if (reg_state[rclass][tmp] == RegState0) {
            best = tmp;
            break;
        }
    }

    return best;
}

void open_temp_registers(void) {
    RegClass rclass;

    for (rclass = 0; rclass < RegClassMax; rclass++) {
        int r = used_virtual_registers[rclass];
        first_temporary_register[rclass] = last_temporary_register[rclass] = r;
    }
}

void check_temp_registers(void) {
    RegClass rclass;

    if (!optimizing) {
        for (rclass = 0; rclass < RegClassMax; rclass++) {
            if (used_virtual_registers[rclass] > last_temporary_register[rclass])
                last_temporary_register[rclass] = used_virtual_registers[rclass];
            if (used_virtual_registers[rclass] > 256)
                used_virtual_registers[rclass] = first_temporary_register[rclass];
        }
    }
}

void close_temp_registers(void) {
    RegClass rclass;

    for (rclass = 0; rclass < RegClassMax; rclass++) {
        if (used_virtual_registers[rclass] < last_temporary_register[rclass])
            used_virtual_registers[rclass] = last_temporary_register[rclass];
        else
            last_temporary_register[rclass] = used_virtual_registers[rclass];
    }
}

int count_scratch_registers(void) {
    RegClass rclass;
    int count;

    count = 0;
    for (rclass = 0; rclass < RegClassMax; rclass++)
        count += n_scratch_registers[rclass];
    return count;
}

void init_modified_registers(void) {
    int i = 0;

    for (i = 0; i < 128; i++)
        mod_regs_table[i] = NULL;
}

static void compute_modified_registers(UInt32 *masks) {
    RegClass rclass;
    PCodeBlock *block;
    PCode *pcode;
    PCodeArg *op;
    int i;

    for (rclass = 0; rclass < RegClassMax; rclass++)
        masks[rclass] = 0;

    for (block = pcbasicblocks; block; block = block->nextBlock) {
        for (pcode = block->firstPCode; pcode; pcode = pcode->nextPCode) {
            op = pcode->args;
            i = pcode->argCount;
            while (i--) {
                if (op->kind == PCOp_REGISTER && (op->data.reg.effect & EffectWrite))
                    masks[op->arg] |= 1 << op->data.reg.reg;
                op++;
            }
        }
    }
}

void note_modified_registers(Object *obj) {
    ModifiedRegisters *mr;

    mr = galloc(sizeof(ModifiedRegisters));
    mr->obj = obj;
    compute_modified_registers(mr->mask);
    mr->next = mod_regs_table[obj->name->hashval & 127];
    mod_regs_table[obj->name->hashval & 127] = mr;
}

void find_modified_registers(Object *obj, UInt32 *masks) {
    RegClass rclass;
    ModifiedRegisters *scan;

    for (rclass = 0; rclass < RegClassMax; rclass++)
        masks[rclass] = 0xFFFFFFFF;

    if (CParser_HasInternalLinkage(obj)) {
        for (scan = mod_regs_table[obj->name->hashval & 127]; scan; scan = scan->next) {
            if (scan->obj == obj)
                break;
        }
        if (scan) {
            for (rclass = 0; rclass < RegClassMax; rclass++)
                masks[rclass] = scan->mask[rclass];
        }
    }
}