cpp.c

cg编译器

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//
// cpp.c
//

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "slglobals.h"

/* Don't use memory.c's replacements, as we clean up properly here */
#undef malloc
#undef free

static int bindAtom = 0;
static int constAtom = 0;
static int defaultAtom = 0;
static int defineAtom = 0;
static int definedAtom = 0;
static int elseAtom = 0;
static int elifAtom = 0;
static int endifAtom = 0;
static int ifAtom = 0;
static int ifdefAtom = 0;
static int ifndefAtom = 0;
static int includeAtom = 0;
static int lineAtom = 0;
static int pragmaAtom = 0;
static int texunitAtom = 0;
static int undefAtom = 0;
static int __LINE__Atom = 0;
static int __FILE__Atom = 0;


static Scope *macros = 0;
#define MAX_MACRO_ARGS  64

static int ifdepth = 0; /* depth of #if nesting -- used to detect invalid
                         * #else/#endif */
static SourceLoc ifloc; /* outermost #if */

int InitCPP(void)
{
    char        buffer[64], *t;
    const char  *f;
    // Add various atoms needed by the CPP line scanner:
    bindAtom = LookUpAddString(atable, "bind");
    constAtom = LookUpAddString(atable, "const");
    defaultAtom = LookUpAddString(atable, "default");
    defineAtom = LookUpAddString(atable, "define");
    definedAtom = LookUpAddString(atable, "defined");
    elifAtom = LookUpAddString(atable, "elif");
    elseAtom = LookUpAddString(atable, "else");
    endifAtom = LookUpAddString(atable, "endif");
    ifAtom = LookUpAddString(atable, "if");
    ifdefAtom = LookUpAddString(atable, "ifdef");
    ifndefAtom = LookUpAddString(atable, "ifndef");
    includeAtom = LookUpAddString(atable, "include");
    lineAtom = LookUpAddString(atable, "line");
    pragmaAtom = LookUpAddString(atable, "pragma");
    texunitAtom = LookUpAddString(atable, "texunit");
    undefAtom = LookUpAddString(atable, "undef");
    __LINE__Atom = LookUpAddString(atable, "__LINE__");
    __FILE__Atom = LookUpAddString(atable, "__FILE__");
    macros = NewScopeInPool(mem_CreatePool(0, 0));
    strcpy(buffer, "PROFILE_");
    t = buffer + strlen(buffer);
    f = Cg->options.profileString;
    while ((isalnum(*f) || *f == '_') && t < buffer + sizeof(buffer) - 1)
        *t++ = toupper(*f++);
    *t = 0;
    PredefineMacro(buffer);
    return 1;
} // InitCPP

int FinalCPP(void)
{
    if (ifdepth)
        SemanticWarning(&ifloc, WARNING___CPP_IF_MISMATCH, "if");
    return 1;
}

static int CPPdefine()
{
    int token, name, args[MAX_MACRO_ARGS], argc;
    MacroSymbol mac;
    Symbol *symb;
    SourceLoc dummyLoc;

    memset(&mac, 0, sizeof(mac));
    token = Cg->currentInput->scan(Cg->currentInput);
    if (token != IDENT_SY) {
        SemanticError(Cg->tokenLoc, ERROR___CPP_SYNTAX, "define");
        return token;
    }
    name = yylval.sc_ident;
    token = Cg->currentInput->scan(Cg->currentInput);
    if (token == '(' && !yylval.sc_int) {
        // gather arguments
        argc = 0;
        do {
            token = Cg->currentInput->scan(Cg->currentInput);
            if (argc == 0 && token == ')') break;
            if (token != IDENT_SY) {
                SemanticError(Cg->tokenLoc, ERROR___CPP_SYNTAX, "define");
                return token;
            }
            if (argc < MAX_MACRO_ARGS)
                args[argc++] = yylval.sc_ident;
            token = Cg->currentInput->scan(Cg->currentInput);
        } while (token == ',');
        if (token != ')') {
            SemanticError(Cg->tokenLoc, ERROR___CPP_SYNTAX, "define");
            return token;
        }
        mac.argc = argc;
        mac.args = mem_Alloc(macros->pool, argc * sizeof(int));
        memcpy(mac.args, args, argc * sizeof(int));
        token = Cg->currentInput->scan(Cg->currentInput);
    }
    mac.body = NewTokenStream(GetAtomString(atable, name));
    while (token != '\n') {
        while (token == '\\') {
            token = Cg->currentInput->scan(Cg->currentInput);
            if (token == '\n')
                token = Cg->currentInput->scan(Cg->currentInput);
            else
                RecordToken(mac.body, '\\');
        }
        RecordToken(mac.body, token);
        token = Cg->currentInput->scan(Cg->currentInput);
    };

    symb = LookUpSymbol(macros, name);
    if (symb) {
        if (!symb->details.mac.undef) {
            // already defined -- need to make sure they are identical
            if (symb->details.mac.argc != mac.argc) goto error;
            for (argc=0; argc < mac.argc; argc++)
                if (symb->details.mac.args[argc] != mac.args[argc])
                    goto error;
            RewindTokenStream(symb->details.mac.body);
            RewindTokenStream(mac.body);
            do {
                int old_lval, old_token;
                old_token = ReadToken(symb->details.mac.body);
                old_lval = yylval.sc_int;
                token = ReadToken(mac.body);
                if (token != old_token || yylval.sc_int != old_lval) {
                error:
                    SemanticWarning(Cg->tokenLoc, WARNING___CPP_MACRO_REDEFINED,
                                    GetAtomString(atable, name));
                    break; }
            } while (token > 0);
        }
        FreeMacro(&symb->details.mac);
    } else {
        dummyLoc.file = 0;
        dummyLoc.line = 0;
        symb = AddSymbol(&dummyLoc, macros, name, 0, MACRO_S);
    }
    symb->details.mac = mac;
    return '\n';
} // CPPdefine

static int CPPundef()
{
    int token = Cg->currentInput->scan(Cg->currentInput);
    Symbol *symb;

    if (token != IDENT_SY) goto error;
    symb = LookUpSymbol(macros, yylval.sc_ident);
    if (symb) {
        symb->details.mac.undef = 1;
    }
    token = Cg->currentInput->scan(Cg->currentInput);
    if (token != '\n') {
    error:
        SemanticError(Cg->tokenLoc, ERROR___CPP_SYNTAX, "undef");
    }
    return token;
} // CPPundef

static int CPPif();

/* CPPelse -- skip forward to appropriate spot.  This is actually used
** to skip to and #endif after seeing an #else, AND to skip to a #else,
** #elif, or #endif after a #if/#ifdef/#ifndef/#elif test was false
*/

static int CPPelse(int matchelse)
{
    int atom, depth = 0;
    int token = Cg->currentInput->scan(Cg->currentInput);
    while (token > 0) {
        while (token != '\n')
            token = Cg->currentInput->scan(Cg->currentInput);
        if ((token = Cg->currentInput->scan(Cg->currentInput)) != '#')
            continue;
        if ((token = Cg->currentInput->scan(Cg->currentInput)) != IDENT_SY)
            continue;
        atom = yylval.sc_ident;
        if (atom == ifAtom || atom == ifdefAtom || atom == ifndefAtom)
            depth++;
        else if (atom == endifAtom) {
            if (--depth < 0) {
                if (ifdepth) ifdepth--;
                break;
            }
        }
        else if (matchelse && depth == 0) {
            if (atom == elseAtom)
                break;
            else if (atom == elifAtom) {
                /* we decrement ifdepth here, because CPPif will increment
                 * it and we really want to leave it alone */
                if (ifdepth) ifdepth--;
                return CPPif();
            }
        }
    };
    return token;
}

enum eval_prec {
    MIN_PREC,
    COND, LOGOR, LOGAND, OR, XOR, AND, EQUAL, RELATION, SHIFT, ADD, MUL, UNARY,
    MAX_PREC
};

static int op_logor(int a, int b) { return a || b; }
static int op_logand(int a, int b) { return a && b; }
static int op_or(int a, int b) { return a | b; }
static int op_xor(int a, int b) { return a ^ b; }
static int op_and(int a, int b) { return a & b; }
static int op_eq(int a, int b) { return a == b; }
static int op_ne(int a, int b) { return a != b; }
static int op_ge(int a, int b) { return a >= b; }
static int op_le(int a, int b) { return a <= b; }
static int op_gt(int a, int b) { return a > b; }
static int op_lt(int a, int b) { return a < b; }
static int op_shl(int a, int b) { return a << b; }
static int op_shr(int a, int b) { return a >> b; }
static int op_add(int a, int b) { return a + b; }
static int op_sub(int a, int b) { return a - b; }
static int op_mul(int a, int b) { return a * b; }
static int op_div(int a, int b) { return a / b; }
static int op_mod(int a, int b) { return a % b; }
static int op_pos(int a) { return a; }
static int op_neg(int a) { return -a; }
static int op_cmpl(int a) { return ~a; }
static int op_not(int a) { return !a; }

struct {
    int token, prec, (*op)(int, int);
} binop[] = {
    { OR_SY, LOGOR, op_logor },
    { AND_SY, LOGAND, op_logand },
    { '|', OR, op_or },
    { '^', XOR, op_xor },
    { '&', AND, op_and },
    { EQ_SY, EQUAL, op_eq },
    { NE_SY, EQUAL, op_ne },
    { '>', RELATION, op_gt },
    { GE_SY, RELATION, op_ge },
    { '<', RELATION, op_lt },
    { LE_SY, RELATION, op_le },
    { LL_SY, SHIFT, op_shl },
    { GG_SY, SHIFT, op_shr },
    { '+', ADD, op_add },
    { '-', ADD, op_sub },
    { '*', MUL, op_mul },
    { '/', MUL, op_div },
    { '%', MUL, op_mod },
};

struct {
    int token, (*op)(int);
} unop[] = {
    { '+', op_pos },
    { '-', op_neg },
    { '~', op_cmpl },
    { '!', op_not },
};

#define ALEN(A) (sizeof(A)/sizeof(A[0]))

int eval(int token, int prec, int *res, int *err)
{
    int         i, val;
    Symbol      *s;

    if (token == IDENT_SY) {
        if (yylval.sc_ident == definedAtom) {
            int needclose = 0;

            token = Cg->currentInput->scan(Cg->currentInput);
            if (token == '(') {
                needclose = 1;
                token = Cg->currentInput->scan(Cg->currentInput);
            }
            if (token != IDENT_SY)
                goto error;
            *res = (s = LookUpSymbol(macros, yylval.sc_ident))
                        ? !s->details.mac.undef : 0;
            token = Cg->currentInput->scan(Cg->currentInput);
            if (needclose) {
                if (token != ')')
                    goto error;
                token = Cg->currentInput->scan(Cg->currentInput);
            }
        } else if (MacroExpand(yylval.sc_ident)) {
            token = Cg->currentInput->scan(Cg->currentInput);
            return eval(token, prec, res, err);
        } else {
            goto error;
        }
    } else if (token == INTCONST_SY) {
        *res = yylval.sc_int;
        token = Cg->currentInput->scan(Cg->currentInput);
    } else if (token == '(') {
        token = Cg->currentInput->scan(Cg->currentInput);
        token = eval(token, MIN_PREC, res, err);
        if (!*err) {
            if (token != ')')
                goto error;
            token = Cg->currentInput->scan(Cg->currentInput);
        }
    } else {
        for (i = ALEN(unop) - 1; i >= 0; i--) {
            if (unop[i].token == token)
                break;
        }
        if (i >= 0) {
            token = Cg->currentInput->scan(Cg->currentInput);
            token = eval(token, UNARY, res, err);
            *res = unop[i].op(*res);
        } else {
            goto error;
        }
    }
    while (!*err) {
        if (token == ')' || token == '\n') break;
        for (i = ALEN(binop) - 1; i >= 0; i--) {
            if (binop[i].token == token)
                break;
        }
        if (i < 0 || binop[i].prec <= prec)
            break;
        val = *res;
        token = Cg->currentInput->scan(Cg->currentInput);
        token = eval(token, binop[i].prec, res, err);
        *res = binop[i].op(val, *res);
    }
    return token;
error:
    SemanticError(Cg->tokenLoc, ERROR___CPP_SYNTAX, "if");
    *err = 1;
    *res = 0;
    return token;
} // eval

static int CPPif() {
    int token = Cg->currentInput->scan(Cg->currentInput);
    int res = 0, err = 0;

    if (!ifdepth++)
        ifloc = *Cg->tokenLoc;
    token = eval(token, MIN_PREC, &res, &err);
    if (token != '\n') {
        SemanticError(Cg->tokenLoc, ERROR___CPP_SYNTAX, "if");
    } else if (!res && !err) {
        token = CPPelse(1);
    }
    return token;
} // CPPif

static int CPPifdef(int defined)
{
    int token = Cg->currentInput->scan(Cg->currentInput);
    int name = yylval.sc_ident;
    ifdepth++;
    if (token != IDENT_SY) {
        SemanticError(Cg->tokenLoc, ERROR___CPP_SYNTAX,
                      defined ? "ifdef" : "ifndef");
    } else {
        Symbol *s = LookUpSymbol(macros, name);
        if (((s && !s->details.mac.undef) ? 1 : 0) != defined)
            token = CPPelse(1);