MWCC/compiler_and_linker/unsorted/Switch.c

#include "compiler/Switch.h"
#include "compiler/CError.h"
#include "compiler/CFunc.h"
#include "compiler/CInt64.h"
#include "compiler/CParser.h"
#include "compiler/InstrSelection.h"
#include "compiler/ObjGenMachO.h"
#include "compiler/Operands.h"
#include "compiler/PCode.h"
#include "compiler/PCodeUtilities.h"
#include "compiler/RegisterInfo.h"
#include "compiler/TOC.h"
#include "compiler/CompilerTools.h"
#include "compiler/objects.h"

ObjectList *switchtables;
static SwitchCase **caselabels;
static CaseRange *caseranges;
static SInt32 ncases;
static SInt32 nranges_minus1;
static CInt64 min;
static CInt64 max;
static CInt64 first;
static short selector_gpr;
static short selector_gprHi;
static Type *selector_type;
static PCodeLabel *defaultlabel;
static CInt64 range;

static int compare_cases(const void *a, const void *b) {
    const SwitchCase **casea = (const SwitchCase **) a;
    const SwitchCase **caseb = (const SwitchCase **) b;

    if (CInt64_Less((*casea)->min, (*caseb)->min))
        return -1;
    if (CInt64_Greater((*casea)->min, (*caseb)->min))
        return 1;
    return 0;
}

static void build_case_ranges(Type *type, SwitchCase *cases, CLabel *label) {
    SwitchCase **caseptr;
    SInt32 i;
    SwitchCase *curcase;
    CaseRange *currange;

    if (type->size == 8) {
        min.lo = 0;
        min.hi = 0x80000000;
        max.lo = 0xFFFFFFFF;
        max.hi = 0x7FFFFFFF;
    } else if (type->size == 4) {
        CInt64_SetLong(&min, 0x80000000);
        CInt64_SetLong(&max, 0x7FFFFFFF);
    } else if (is_unsigned(type)) {
        min.hi = 0;
        min.lo = 0;
        max.hi = 0;
        max.lo = 0xFFFF;
    } else {
        CInt64_SetLong(&min, -0x8000);
        CInt64_SetLong(&max, 0x7FFF);
    }

    caselabels = lalloc(sizeof(SwitchCase *) * ncases);
    caseptr = caselabels;
    while (cases) {
        *caseptr = cases;
        cases = cases->next;
        ++caseptr;
    }

    caseranges = lalloc(((ncases * 2) + 2) * sizeof(CaseRange));
    if (type->size < 8) {
        for (i = 0; i < ncases; i++)
            CInt64_SetLong(&caselabels[i]->min, caselabels[i]->min.lo);
    }

    qsort(caselabels, ncases, sizeof(SwitchCase *), &compare_cases);

    currange = caseranges;
    currange->min = min;
    currange->range = CInt64_Sub(max, min);
    currange->label = label->pclabel;

    for (i = 0; i < ncases; i++) {
        curcase = caselabels[i];
        if (CInt64_GreaterEqual(curcase->min, min) && CInt64_LessEqual(curcase->min, max)) {
            if (CInt64_Equal(currange->min, min))
                first = curcase->min;
            range = CInt64_Sub(curcase->min, first);

            if (CInt64_Greater(curcase->min, currange->min)) {
                currange->range = CInt64_Sub(CInt64_Sub(curcase->min, currange->min), cint64_one);
                (++currange)->min = curcase->min;
            } else if (CInt64_Greater(currange->min, min) && curcase->label->pclabel == currange[-1].label) {
                currange[-1].range = CInt64_Add(currange[-1].range, cint64_one);
                if (CInt64_Equal(currange->range, cint64_zero)) {
                    currange--;
                } else {
                    currange->min = CInt64_Add(currange->min, cint64_one);
                    currange->range = CInt64_Sub(currange->range, cint64_one);
                }
                continue;
            }

            currange->range = cint64_zero;
            currange->label = curcase->label->pclabel;

            if (CInt64_Less(curcase->min, max)) {
                currange++;
                currange->min = CInt64_Add(curcase->min, cint64_one);
                currange->range = CInt64_Sub(max, currange->min);
                currange->label = label->pclabel;
            }
        }
    }

    nranges_minus1 = currange - caseranges;
}

static void treecompare(SInt32 start, SInt32 end) {
    SInt32 r30;
    SInt32 r29;
    CaseRange *currange;
    int count;

    count = end - start;
    CError_ASSERT(175, selector_type->size <= 4);

    r29 = start + (count >> 1) + 1;
    currange = caseranges + r29;

    if (CInt64_Equal(currange[-1].range, cint64_zero) && (!(count & 1) || (CInt64_NotEqual(currange->range, cint64_zero) && count > 1))) {
        currange--;
        r29--;
    }

    r30 = r29 - 1;

    if (selector_type->size < 4 && is_unsigned(selector_type)) {
        emitpcode(PC_CMPLI, 0, selector_gpr, CInt64_GetULong(&currange->min));
    } else if (FITS_IN_SHORT((SInt32) CInt64_GetULong(&currange->min))) {
        emitpcode(PC_CMPI, 0, selector_gpr, CInt64_GetULong(&currange->min));
    } else {
        SInt32 value = CInt64_GetULong(&currange->min);
        int reg = ALLOC_GPR();
        load_immediate(reg, value);
        emitpcode(PC_CMP, 0, selector_gpr, reg);
    }

    if (CInt64_Equal(currange->range, cint64_zero) && r29 < end) {
        branch_conditional(0, EEQU, 1, currange->label);
        r29++;
    }

    if (r29 == end) {
        if (start == r30) {
            if (caseranges[start].label == caseranges[end].label) {
                branch_always(caseranges[start].label);
            } else {
                branch_conditional(0, EGREATEREQU, 1, caseranges[end].label);
                branch_always(caseranges[start].label);
            }
        } else {
            branch_conditional(0, EGREATEREQU, 1, caseranges[end].label);
            treecompare(start, r30);
        }
    } else {
        if (start == r30) {
            branch_conditional(0, ELESS, 1, caseranges[start].label);
            treecompare(r29, end);
        } else {
            PCodeLabel *label = makepclabel();
            branch_conditional(0, EGREATEREQU, 1, label);
            treecompare(start, r30);
            branch_label(label);
            treecompare(r29, end);
        }
    }
}

static void I8_treecompare(SInt32 start, SInt32 end) {
    SInt32 r30;
    SInt32 r29;
    CaseRange *currange;
    int count;

    count = end - start;

    r29 = start + (count >> 1) + 1;
    currange = caseranges + r29;

    if (CInt64_Equal(currange[-1].range, cint64_zero) && (!(count & 1) || (CInt64_NotEqual(currange->range, cint64_zero) && count > 1))) {
        currange--;
        r29--;
    }

    r30 = r29 - 1;

    if (CInt64_Equal(currange->range, cint64_zero) && r29 < end) {
        short a = ALLOC_GPR();
        short b = ALLOC_GPR();
        load_immediate(a, currange->min.lo);
        load_immediate(b, currange->min.hi);
        emitpcode(PC_XOR, a, selector_gpr, a);
        emitpcode(PC_XOR, b, selector_gprHi, b);
        emitpcode(PC_OR, b, a, b);
        emitpcode(PC_CMPI, 0, b, 0);
        branch_conditional(0, EEQU, 1, currange->label);
        r29++;
    }

    if (r29 == end) {
        if (start == r30) {
            if (caseranges[start].label == caseranges[end].label) {
                branch_always(caseranges[start].label);
            } else {
                short a = ALLOC_GPR();
                short b = ALLOC_GPR();
                short c = ALLOC_GPR();
                short d = ALLOC_GPR();
                load_immediate(a, currange->min.lo);
                load_immediate(b, currange->min.hi);
                if (TYPE_INTEGRAL(selector_type)->integral != IT_ULONGLONG && TYPE_INTEGRAL(selector_type)->integral != IT_ULONGLONG) {
                    emitpcode(PC_XORIS, c, selector_gprHi, 0x8000);
                    emitpcode(PC_XORIS, d, b, 0x8000);
                } else {
                    c = selector_gprHi;
                    d = b;
                }
                emitpcode(PC_SUBFC, a, a, selector_gpr);
                emitpcode(PC_SUBFE, b, d, c);
                emitpcode(PC_SUBFE, b, a, a);
                emitpcode(PC_NEG, b, b);
                emitpcode(PC_CMPI, 0, b, 0);
                branch_conditional(0, EEQU, 1, caseranges[end].label);
                branch_always(caseranges[start].label);
            }
        } else {
            short a = ALLOC_GPR();
            short b = ALLOC_GPR();
            short c = ALLOC_GPR();
            short d = ALLOC_GPR();
            load_immediate(a, currange->min.lo);
            load_immediate(b, currange->min.hi);
            if (TYPE_INTEGRAL(selector_type)->integral != IT_ULONGLONG && TYPE_INTEGRAL(selector_type)->integral != IT_ULONGLONG) {
                emitpcode(PC_XORIS, c, selector_gprHi, 0x8000);
                emitpcode(PC_XORIS, d, b, 0x8000);
            } else {
                c = selector_gprHi;
                d = b;
            }
            emitpcode(PC_SUBFC, a, a, selector_gpr);
            emitpcode(PC_SUBFE, b, d, c);
            emitpcode(PC_SUBFE, b, a, a);
            emitpcode(PC_NEG, b, b);
            emitpcode(PC_CMPI, 0, b, 0);
            branch_conditional(0, EEQU, 1, caseranges[end].label);
            I8_treecompare(start, r30);
        }
    } else {
        if (start == r30) {
            short a = ALLOC_GPR();
            short b = ALLOC_GPR();
            short c = ALLOC_GPR();
            short d = ALLOC_GPR();
            load_immediate(a, currange->min.lo);
            load_immediate(b, currange->min.hi);
            if (TYPE_INTEGRAL(selector_type)->integral != IT_ULONGLONG && TYPE_INTEGRAL(selector_type)->integral != IT_ULONGLONG) {
                emitpcode(PC_XORIS, c, selector_gprHi, 0x8000);
                emitpcode(PC_XORIS, d, b, 0x8000);
            } else {
                c = selector_gprHi;
                d = b;
            }
            emitpcode(PC_SUBFC, a, selector_gpr, a);
            emitpcode(PC_SUBFE, b, c, d);
            emitpcode(PC_SUBFE, b, a, a);
            emitpcode(PC_NEG, b, b);
            emitpcode(PC_CMPI, 0, b, 0);
            branch_conditional(0, ENOTEQU, 1, caseranges[end].label);
            I8_treecompare(r29, end);
        } else {
            PCodeLabel *label;
            short a = ALLOC_GPR();
            short b = ALLOC_GPR();
            short c = ALLOC_GPR();
            short d = ALLOC_GPR();
            load_immediate(a, currange->min.lo);
            load_immediate(b, currange->min.hi);
            if (TYPE_INTEGRAL(selector_type)->integral != IT_ULONGLONG && TYPE_INTEGRAL(selector_type)->integral != IT_ULONGLONG) {
                emitpcode(PC_XORIS, c, selector_gprHi, 0x8000);
                emitpcode(PC_XORIS, d, b, 0x8000);
            } else {
                c = selector_gprHi;
                d = b;
            }
            emitpcode(PC_SUBFC, a, a, selector_gpr);
            emitpcode(PC_SUBFE, b, d, c);
            emitpcode(PC_SUBFE, b, a, a);
            emitpcode(PC_NEG, b, b);
            emitpcode(PC_CMPI, 0, b, 0);
            label = makepclabel();
            branch_conditional(0, EEQU, 1, label);
            I8_treecompare(start, r30);
            branch_label(label);
            I8_treecompare(r29, end);
        }
    }
}

static void generate_tree(ENode *expr) {
    Operand op;

    memclrw(&op, sizeof(Operand));
    if (TYPE_IS_8BYTES(expr->rtype)) {
        GEN_NODE(expr, &op);
        coerce_to_register_pair(&op, expr->rtype, 0, 0);
        selector_type = expr->rtype;
        selector_gpr = op.reg;
        selector_gprHi = op.regHi;
        I8_treecompare(0, nranges_minus1);
    } else {
        GEN_NODE(expr, &op);
        if (expr->rtype->size < 4)
            extend32(&op, expr->rtype, 0);
        ENSURE_GPR(&op, expr->rtype, 0);
        selector_type = expr->rtype;
        selector_gpr = op.reg;
        treecompare(0, nranges_minus1);
    }
}

static Object *create_switch_table(void) {
    Object *obj;
    ObjectList *list;
    UInt32 *outptr;
    CaseRange *currange;
    SInt32 size;
    CInt64 value;

    obj = galloc(sizeof(Object));
    list = galloc(sizeof(ObjectList));
    memclrw(obj, sizeof(Object));
    memclrw(list, sizeof(ObjectList));

    obj->otype = OT_OBJECT;
    obj->access = ACCESSPUBLIC;
    obj->datatype = DDATA;
    obj->name = CParser_GetUniqueName();
    obj->toc = NULL;
    obj->sclass = TK_STATIC;
    obj->qual = Q_CONST;
    obj->flags |= OBJECT_FLAGS_2 | OBJECT_DEFINED;
    obj->u.data.linkname = obj->name;
    obj->type = NULL;
    createIndirect(obj, 0, 0);
    obj->type = TYPE(&void_ptr);

    size = CInt64_GetULong(&range) + 1;
    obj->u.data.u.switchtable.size = size;
    obj->u.data.u.switchtable.data = lalloc(4 * size);

    currange = caseranges;
    outptr = (UInt32 *) obj->u.data.u.switchtable.data;
    value = cint64_zero;
    while (CInt64_LessEqual(value, range)) {
        while (CInt64_Greater(CInt64_Add(first, value), CInt64_Add(currange->min, currange->range)))
            currange++;
        *outptr = CTool_CreateIndexFromPointer(currange->label);
        value = CInt64_Add(value, cint64_one);
        outptr++;
    }

    list->object = obj;
    list->next = switchtables;
    switchtables = list;
    return list->object;
}

static void generate_table(ENode *expr, SwitchInfo *info) {
    Object *table;
    SwitchCase *curcase;
    short reg;
    short reg2;
    short reg3;
    Operand op1;
    Operand op2;

    CInt64 val3 = {0, 3};
    memclrw(&op1, sizeof(Operand));
    memclrw(&op2, sizeof(Operand));

    if (CInt64_Greater(first, cint64_zero) && CInt64_Less(first, val3)) {
        range = CInt64_Add(range, first);
        first = cint64_zero;
    }

    table = create_switch_table();
    CError_ASSERT(553, !TYPE_IS_8BYTES(expr->rtype));

    GEN_NODE(expr, &op1);
    if (expr->rtype->size < 4)
        extend32(&op1, expr->rtype, 0);
    ENSURE_GPR(&op1, expr->rtype, 0);

    reg = op1.reg;
    if (CInt64_NotEqual(first, cint64_zero)) {
        SInt32 value;
        reg = ALLOC_GPR();
        value = -CInt64_GetULong(&first);
        if (!FITS_IN_SHORT(value)) {
            emitpcode(PC_ADDIS, reg, op1.reg, 0, HIGH_PART(value));
            if (value)
                emitpcode(PC_ADDI, reg, reg, 0, LOW_PART(value));
        } else {
            emitpcode(PC_ADDI, reg, op1.reg, 0, value);
        }
    }

    if (!FITS_IN_SHORT(CInt64_GetULong(&range))) {
        short tmp = ALLOC_GPR();
        load_immediate(tmp, CInt64_GetULong(&range));
        emitpcode(PC_CMPL, 0, reg, tmp);
    } else {
        emitpcode(PC_CMPLI, 0, reg, CInt64_GetULong(&range));
    }

    branch_conditional(0, EGREATER, 1, defaultlabel);
    if (table->toc) {
        op2.optype = OpndType_Symbol;
        op2.object = table->toc;
        indirect(&op2, NULL);
    } else {
        op2.optype = OpndType_Symbol;
        op2.object = table;
    }

    if (op2.optype != OpndType_GPR) {
        Coerce_to_register(&op2, TYPE(&void_ptr), reg2 = ALLOC_GPR());
    }

    if (op2.optype != OpndType_GPR) {
        CError_FATAL(599);
    } else {
        if (op2.reg != reg2)
            emitpcode(PC_MR, reg2, op2.reg);
    }

    if (CInt64_Equal(first, cint64_zero)) {
        reg = ALLOC_GPR();
        emitpcode(PC_RLWINM, reg, op1.reg, 2, 0, 29);
    } else {
        emitpcode(PC_RLWINM, reg, reg, 2, 0, 29);
    }

    reg3 = reg2;
    emitpcode(PC_LWZX, reg3, reg3, reg);
    for (curcase = info->cases; curcase; curcase = curcase->next)
        pcbranch(pclastblock, curcase->label->pclabel);
    pcbranch(pclastblock, info->defaultlabel->pclabel);
    emitpcode(PC_MTCTR, reg3);
    branch_indirect(table);
}

void switchstatement(ENode *expr, SwitchInfo *info) {
    Boolean use_table;
    SwitchCase *swcase;

    use_table = copts.switch_tables;

    ncases = 0;
    for (swcase = info->cases; swcase; swcase = swcase->next) {
        if (!swcase->label->pclabel)
            swcase->label->pclabel = makepclabel();
        ncases++;
    }

    CError_ASSERT(656, ncases >= 0 && ncases <= 0x3333332U);

    if (!info->defaultlabel->pclabel)
        info->defaultlabel->pclabel = makepclabel();
    defaultlabel = info->defaultlabel->pclabel;

    build_case_ranges(expr->rtype, info->cases, info->defaultlabel);

    if (TYPE_IS_8BYTES(expr->rtype)) {
        generate_tree(expr);
        return;
    }

    if (!use_table || nranges_minus1 < 8 || (nranges_minus1 * 2) < ((range.lo / 2) + 4))
        generate_tree(expr);
    else
        generate_table(expr, info);
}

void dumpswitchtables(Object *funcobj) {
    Object *table;
    ObjectList *list;
    SInt32 size;
    UInt32 *array;

    for (list = switchtables; list; list = list->next) {
        table = list->object;
        CError_ASSERT(694, table->otype == OT_OBJECT && table->access == ACCESSPUBLIC && table->datatype == DDATA);

        size = table->u.data.u.switchtable.size;
        array = (UInt32 *) table->u.data.u.switchtable.data;
        while (size--) {
            *array = CTool_EndianConvertWord32(((PCodeLabel *) CTool_ResolveIndexToPointer(*array))->block->codeOffset);
            array++;
        }

        ObjGen_DeclareSwitchTable(table, funcobj);
    }
}