ref: 0e5c97b6bbb089afe3a34ecb2ffbbaf960580d61
dir: /cc1/fold.c/
#include <stdio.h> #include "../inc/cc.h" #include "cc1.h" static bool addi(TINT l, TINT r, Type *tp) { struct limits *lim = getlimits(tp); TINT max = lim->max.i, min = lim->min.i; if (l < 0 && r < 0 && l >= min - r || l == 0 || r == 0 || l < 0 && r > 0 || l > 0 && r < 0 || l > 0 && r > 0 && l <= max - r) { return 1; } warn("overflow in constant expression"); return 0; } static bool addf(TFLOAT l, TFLOAT r, Type *tp) { struct limits *lim = getlimits(tp); TFLOAT max = lim->max.f, min = lim->min.f; if (l < 0 && r < 0 && l >= min - r || l == 0 || r == 0 || l < 0 && r > 0 || l > 0 && r < 0 || l > 0 && r > 0 && l <= max - r) { return 1; } warn("overflow in constant expression"); return 0; } static bool subi(TINT l, TINT r, Type *tp) { return addi(l, -r, tp); } static bool subf(TFLOAT l, TFLOAT r, Type *tp) { return addf(l, -r, tp); } static bool muli(TINT l, TINT r, Type *tp) { struct limits *lim = getlimits(tp); TINT max = lim->max.i, min = lim->min.i; if (l > -1 && l <= 1 || r > -1 && r <= 1 || l < 0 && r < 0 && -l <= max/-r || l < 0 && r > 0 && l >= min/r || l > 0 && r < 0 && r >= min/l || l > 0 && r > 0 && l <= max/r) { return 1; } warn("overflow in constant expression"); return 0; } static bool mulf(TFLOAT l, TFLOAT r, Type *tp) { struct limits *lim = getlimits(tp); TFLOAT max = lim->max.i, min = lim->min.i; if (l > -1 && l <= 1 || r > -1 && r <= 1 || l < 0 && r < 0 && -l <= max/-r || l < 0 && r > 0 && l >= min/r || l > 0 && r < 0 && r >= min/l || l > 0 && r > 0 && l <= max/r) { return 1; } warn("overflow in constant expression"); return 0; } static bool divi(TINT l, TINT r, Type *tp) { struct limits *lim = getlimits(tp); if (r == 0 || l == lim->min.i && r == -1) { warn("overflow in constant expression"); return 0; } return 1; } static bool divf(TFLOAT l, TFLOAT r, Type *tp) { struct limits *lim = getlimits(tp); if (l < 0) l = -l; if (r < 0) r = -r; if (r == 0.0 || r < 1.0 && l > lim->max.f * r) { warn("overflow in constant expression"); return 0; } return 1; } static bool lshi(TINT l, TINT r, Type *tp) { if (r < 0 || r >= tp->size * 8) { warn("shifting %d bits is undefined", r); return 0; } return muli(l, 1 << r, tp); } static bool rshi(TINT l, TINT r, Type *tp) { if (r < 0 || r >= tp->size * 8) { warn("shifting %d bits is undefined", r); return 0; } return 1; } static bool foldint(int op, Symbol *res, TINT l, TINT r) { TINT i; Type *tp = res->type; bool (*validate)(TINT, TINT, Type *tp); switch (op) { case OADD: validate = addi; break; case OSUB: validate = subi; break; case OMUL: validate = muli; break; case ODIV: validate = divi; break; case OSHL: validate = lshi; break; case OSHR: validate = rshi; break; case OMOD: validate = divi; break; default: validate = NULL; break; } if (validate && !(*validate)(l, r, tp)) return 0; switch (op) { case OADD: i = l + r; break; case OSUB: i = l - r; break; case OMUL: i = l * r; break; case ODIV: i = l / r; break; case OMOD: i = l % r; break; case OSHL: i = l << r; break; case OSHR: i = l >> r; break; case OBAND: i = l & r; break; case OBXOR: i = l ^ r; break; case OBOR: i = l | r; break; case OAND: i = l && r; break; case OOR: i = l || r; break; case OLT: i = l < r; break; case OGT: i = l > r; break; case OGE: i = l >= r; break; case OLE: i = l <= r; break; case OEQ: i = l == r; break; case ONE: i = l != r; break; case ONEG: i = -l; break; case OCPL: i = ~l; break; default: return 0; } res->u.i = i; return 1; } static bool folduint(int op, Symbol *res, TINT l, TINT r) { TINT i; TUINT u; switch (op) { case OADD: u = l + r; break; case OSUB: u = l - r; break; case OMUL: u = l * r; break; case ODIV: u = l / r; break; case OMOD: u = l % r; break; case OSHL: u = l << r; break; case OSHR: u = l >> r; break; case OBAND: u = l & r; break; case OBXOR: u = l ^ r; break; case OBOR: u = l | r; break; case ONEG: u = -l; break; case OCPL: u = ~l; break; case OAND: i = l && r; goto unsign; case OOR: i = l || r; goto unsign; case OLT: i = l < r; goto unsign; case OGT: i = l > r; goto unsign; case OGE: i = l >= r; goto unsign; case OLE: i = l <= r; goto unsign; case OEQ: i = l == r; goto unsign; case ONE: i = l != r; goto unsign; default: return 0; } sign: res->u.u = u; return 1; unsign: res->u.i = i; return 1; } static bool foldfloat(int op, Symbol *res, TFLOAT l, TFLOAT r) { TFLOAT f; TINT i; bool (*validate)(TFLOAT, TFLOAT, Type *tp); switch (op) { case OADD: validate = addf; break; case OSUB: validate = subf; break; case OMUL: validate = mulf; break; case ODIV: validate = divf; break; default: validate = NULL; break; } if (validate && !(*validate)(l, r, res->type)) return 0; switch (op) { case OADD: f = l + r; break; case OSUB: f = l - r; break; case OMUL: f = l * r; break; case ODIV: f = l / r; break; case OLT: i = l < r; goto comparision; case OGT: i = l > r; goto comparision; case OGE: i = l >= r; goto comparision; case OLE: i = l <= r; goto comparision; case OEQ: i = l == r; goto comparision; case ONE: i = l != r; goto comparision; default: return 0; } res->u.f = f; return 1; comparision: res->u.i = i; return 1; } static Node * foldconst(int type, int op, Type *tp, Symbol *ls, Symbol *rs) { Symbol *sym, aux; TINT i; TUINT u; TFLOAT f; aux.type = tp; switch (type) { case INT: i = (rs) ? rs->u.i : 0; if (!foldint(op, &aux, ls->u.i, i)) return NULL; break; case UNSIGNED: u = (rs) ? rs->u.u : 0u; if (!folduint(op, &aux, ls->u.u, u)) return NULL; break; case FLOAT: f = (rs) ? rs->u.f : 0.0; if (!foldfloat(op, &aux, ls->u.f, f)) return NULL; break; } sym = newsym(NS_IDEN); sym->type = tp; sym->u = aux.u; return constnode(sym); } static Node * fold(int op, Type *tp, Node *lp, Node *rp) { Symbol *rs, *ls; Node *np; int type; if ((op == ODIV || op == OMOD) && cmpnode(rp, 0)) { warn("division by 0"); return NULL; } if (!lp->constant || rp && !rp->constant) return NULL; ls = lp->sym; rs = (rp) ? rp->sym : NULL; /* * Comparision nodes have integer type * but the operands can have different * type. */ type = (isnodecmp(op)) ? BTYPE(lp) : tp->op; switch (type) { case PTR: case INT: type = (tp->sign) ? INT : UNSIGNED; break; case FLOAT: type = FLOAT; break; default: return NULL; } if ((np = foldconst(type, op, tp, ls, rs)) == NULL) return NULL; freetree(lp); freetree(rp); return np; } static void commutative(int *op, Node **lp, Node **rp) { Node *l = *lp, *r = *rp, *aux; if (r == NULL || r->constant || !l->constant) return; switch (*op) { case OLT: case OGT: case OGE: case OLE: case OEQ: case ONE: *op = negop(*op); case OADD: case OMUL: case OBAND: case OBXOR: case OBOR: aux = l; l = r; r = aux; *rp = r; *lp = l; break; } } static TUINT ones(int n) { TUINT v; for (v = 1; n--; v |= 1) v <<= 1; return v; } /* * i || 0 => i,0 * i || 1 => i * i && 0 => i,0 * i && 1 => i * i >> 0 => i * i << 0 => i * i + 0 => i * i - 0 => i * i | 0 => i * i ^ 0 => i * i * 0 => i,0 * i * 1 => i * i / 1 => i * i & ~0 => i * i % 1 => i,1 */ static Node * identity(int *op, Node *lp, Node *rp) { int iszero, isone, istrue; if (!rp) return NULL; iszero = cmpnode(rp, 0); isone = cmpnode(rp, 1), istrue = !iszero && rp->constant; switch (*op) { case OOR: if (istrue) goto change_to_comma; if (iszero) break; return NULL; case OAND: if (iszero) goto change_to_comma; if (istrue) break; return NULL; case OSHL: case OSHR: case OBXOR: case OADD: case OBOR: case OSUB: if (iszero) break; return NULL; case OMUL: if (iszero) goto change_to_comma; case ODIV: if (isone) break; return NULL; case OBAND: if (cmpnode(rp, ones(lp->type->size * 8))) break; return NULL; case OMOD: if (isone) goto change_to_comma; default: return NULL; } freetree(rp); return lp; change_to_comma: *op = OCOMMA; return NULL; } Node * simplify(int op, Type *tp, Node *lp, Node *rp) { Node *np; commutative(&op, &lp, &rp); if ((np = fold(op, tp, lp, rp)) != NULL) return np; if ((np = identity(&op, lp, rp)) != NULL) return np; return node(op, tp, lp, rp); } /* TODO: check validity of types */ Node * castcode(Node *np, Type *newtp) { Type *oldtp = np->type; Symbol aux, *sym, *osym = np->sym; if (!np->constant) goto noconstant; switch (newtp->op) { case PTR: case INT: case ENUM: switch (oldtp->op) { case PTR: case INT: case ENUM: if (newtp->sign == oldtp->sign) aux.u = osym->u; if (newtp->sign && !oldtp->sign) aux.u.i = osym->u.u; else if (!newtp->sign && oldtp->sign) aux.u.u = osym->u.u; break; case FLOAT: if (newtp->sign) aux.u.i = osym->u.f; else aux.u.u = osym->u.f; break; default: goto noconstant; } break; case FLOAT: aux.u.f = (oldtp->sign) ? osym->u.i : osym->u.u; break; default: goto noconstant; } sym = newsym(NS_IDEN); np->type = sym->type = newtp; np->sym = sym; sym->u = aux.u; return np; noconstant: return node(OCAST, newtp, np, NULL); }