/*********************************************************** Copyright 1991, 1992, 1993 by Stichting Mathematisch Centrum, Amsterdam, The Netherlands. All Rights Reserved Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the names of Stichting Mathematisch Centrum or CWI not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. ******************************************************************/ /* Compile an expression node to intermediate code */ /* XXX TO DO: XXX Compute maximum needed stack sizes while compiling XXX Generate simple jump for break/return outside 'try...finally' */ #include "allobjects.h" #include "node.h" #include "token.h" #include "graminit.h" #include "compile.h" #include "opcode.h" #include "structmember.h" #include #include #define OFF(x) offsetof(codeobject, x) static struct memberlist code_memberlist[] = { {"co_code", T_OBJECT, OFF(co_code), READONLY}, {"co_consts", T_OBJECT, OFF(co_consts), READONLY}, {"co_names", T_OBJECT, OFF(co_names), READONLY}, {"co_filename", T_OBJECT, OFF(co_filename), READONLY}, {"co_name", T_OBJECT, OFF(co_name), READONLY}, {NULL} /* Sentinel */ }; static object * code_getattr(co, name) codeobject *co; char *name; { return getmember((char *)co, code_memberlist, name); } static void code_dealloc(co) codeobject *co; { XDECREF(co->co_code); XDECREF(co->co_consts); XDECREF(co->co_names); XDECREF(co->co_filename); XDECREF(co->co_name); DEL(co); } static object * code_repr(co) codeobject *co; { char buf[500]; int lineno = -1; char *p = GETSTRINGVALUE(co->co_code); char *filename = "???"; char *name = "???"; if (*p == SET_LINENO) lineno = (p[1] & 0xff) | ((p[2] & 0xff) << 8); if (co->co_filename && is_stringobject(co->co_filename)) filename = getstringvalue(co->co_filename); if (co->co_name && is_stringobject(co->co_name)) name = getstringvalue(co->co_name); sprintf(buf, "", name, (long)co, filename, lineno); return newstringobject(buf); } typeobject Codetype = { OB_HEAD_INIT(&Typetype) 0, "code", sizeof(codeobject), 0, code_dealloc, /*tp_dealloc*/ 0, /*tp_print*/ code_getattr, /*tp_getattr*/ 0, /*tp_setattr*/ 0, /*tp_compare*/ code_repr, /*tp_repr*/ 0, /*tp_as_number*/ 0, /*tp_as_sequence*/ 0, /*tp_as_mapping*/ }; codeobject * newcodeobject(code, consts, names, filename, name) object *code; object *consts; object *names; object *filename; object *name; { codeobject *co; int i; /* Check argument types */ if (code == NULL || !is_stringobject(code) || consts == NULL || !is_listobject(consts) || names == NULL || !is_listobject(names) || name == NULL || !is_stringobject(name)) { err_badcall(); return NULL; } /* Make sure the list of names contains only strings */ for (i = getlistsize(names); --i >= 0; ) { object *v = getlistitem(names, i); if (v == NULL || !is_stringobject(v)) { err_badcall(); return NULL; } } co = NEWOBJ(codeobject, &Codetype); if (co != NULL) { INCREF(code); co->co_code = (stringobject *)code; INCREF(consts); co->co_consts = consts; INCREF(names); co->co_names = names; INCREF(filename); co->co_filename = filename; INCREF(name); co->co_name = name; } return co; } /* Data structure used internally */ #define MAXBLOCKS 20 /* Max static block nesting within a function */ struct compiling { object *c_code; /* string */ object *c_consts; /* list of objects */ object *c_names; /* list of strings (names) */ object *c_globals; /* dictionary */ int c_nexti; /* index into c_code */ int c_errors; /* counts errors occurred */ int c_infunction; /* set when compiling a function */ int c_inlambda; /* set when compiling an expression */ int c_loops; /* counts nested loops */ int c_begin; /* begin of current loop, for 'continue' */ int c_block[MAXBLOCKS]; /* stack of block types */ int c_nblocks; /* current block stack level */ char *c_filename; /* filename of current node */ char *c_name; /* name of object (e.g. function) */ }; /* Interface to the block stack */ static void block_push(c, type) struct compiling *c; int type; { if (c->c_nblocks >= MAXBLOCKS) { err_setstr(SystemError, "too many statically nested blocks"); c->c_errors++; } else { c->c_block[c->c_nblocks++] = type; } } static void block_pop(c, type) struct compiling *c; int type; { if (c->c_nblocks > 0) c->c_nblocks--; if (c->c_block[c->c_nblocks] != type && c->c_errors == 0) { err_setstr(SystemError, "bad block pop"); c->c_errors++; } } /* Prototypes */ static int com_init PROTO((struct compiling *, char *, int)); static void com_free PROTO((struct compiling *)); static void com_done PROTO((struct compiling *)); static void com_node PROTO((struct compiling *, struct _node *)); static void com_addbyte PROTO((struct compiling *, int)); static void com_addint PROTO((struct compiling *, int)); static void com_addoparg PROTO((struct compiling *, int, int)); static void com_addfwref PROTO((struct compiling *, int, int *)); static void com_backpatch PROTO((struct compiling *, int)); static int com_add PROTO((struct compiling *, object *, object *)); static int com_addconst PROTO((struct compiling *, object *)); static int com_addname PROTO((struct compiling *, object *)); static void com_addopname PROTO((struct compiling *, int, node *)); static void com_list PROTO((struct compiling *, node *, int)); static int com_init(c, filename, inlambda) struct compiling *c; char *filename; int inlambda; { if ((c->c_code = newsizedstringobject((char *)NULL, 1000)) == NULL) goto fail_3; if ((c->c_consts = newlistobject(0)) == NULL) goto fail_2; if ((c->c_names = newlistobject(0)) == NULL) goto fail_1; if ((c->c_globals = newdictobject()) == NULL) goto fail_0; c->c_nexti = 0; c->c_errors = 0; c->c_infunction = 0; c->c_inlambda = inlambda; c->c_loops = 0; c->c_begin = 0; c->c_nblocks = 0; c->c_filename = filename; c->c_name = "?"; return 1; fail_0: DECREF(c->c_names); fail_1: DECREF(c->c_consts); fail_2: DECREF(c->c_code); fail_3: return 0; } static void com_free(c) struct compiling *c; { XDECREF(c->c_code); XDECREF(c->c_consts); XDECREF(c->c_names); XDECREF(c->c_globals); } static void com_done(c) struct compiling *c; { if (c->c_code != NULL) resizestring(&c->c_code, c->c_nexti); } static void com_addbyte(c, byte) struct compiling *c; int byte; { int len; if (byte < 0 || byte > 255) { /* fprintf(stderr, "XXX compiling bad byte: %d\n", byte); abort(); */ err_setstr(SystemError, "com_addbyte: byte out of range"); c->c_errors++; } if (c->c_code == NULL) return; len = getstringsize(c->c_code); if (c->c_nexti >= len) { if (resizestring(&c->c_code, len+1000) != 0) { c->c_errors++; return; } } getstringvalue(c->c_code)[c->c_nexti++] = byte; } static void com_addint(c, x) struct compiling *c; int x; { com_addbyte(c, x & 0xff); com_addbyte(c, x >> 8); /* XXX x should be positive */ } static void com_addoparg(c, op, arg) struct compiling *c; int op; int arg; { com_addbyte(c, op); com_addint(c, arg); } static void com_addfwref(c, op, p_anchor) struct compiling *c; int op; int *p_anchor; { /* Compile a forward reference for backpatching */ int here; int anchor; com_addbyte(c, op); here = c->c_nexti; anchor = *p_anchor; *p_anchor = here; com_addint(c, anchor == 0 ? 0 : here - anchor); } static void com_backpatch(c, anchor) struct compiling *c; int anchor; /* Must be nonzero */ { unsigned char *code = (unsigned char *) getstringvalue(c->c_code); int target = c->c_nexti; int dist; int prev; for (;;) { /* Make the JUMP instruction at anchor point to target */ prev = code[anchor] + (code[anchor+1] << 8); dist = target - (anchor+2); code[anchor] = dist & 0xff; code[anchor+1] = dist >> 8; if (!prev) break; anchor -= prev; } } /* Handle literals and names uniformly */ static int com_add(c, list, v) struct compiling *c; object *list; object *v; { int n = getlistsize(list); int i; for (i = n; --i >= 0; ) { object *w = getlistitem(list, i); if (v->ob_type == w->ob_type && cmpobject(v, w) == 0) return i; } if (addlistitem(list, v) != 0) c->c_errors++; return n; } static int com_addconst(c, v) struct compiling *c; object *v; { return com_add(c, c->c_consts, v); } static int com_addname(c, v) struct compiling *c; object *v; { return com_add(c, c->c_names, v); } static void com_addopname(c, op, n) struct compiling *c; int op; node *n; { object *v; int i; char *name; if (TYPE(n) == STAR) name = "*"; else { REQ(n, NAME); name = STR(n); } if ((v = newstringobject(name)) == NULL) { c->c_errors++; i = 255; } else { i = com_addname(c, v); DECREF(v); } /* Hack to replace *_NAME opcodes by *_GLOBAL if necessary */ switch (op) { case LOAD_NAME: case STORE_NAME: case DELETE_NAME: if (dictlookup(c->c_globals, name) != NULL) { switch (op) { case LOAD_NAME: op = LOAD_GLOBAL; break; case STORE_NAME: op = STORE_GLOBAL; break; case DELETE_NAME: op = DELETE_GLOBAL; break; } } } com_addoparg(c, op, i); } static object * parsenumber(s) char *s; { extern long strtol PROTO((const char *, char **, int)); extern unsigned long strtoul PROTO((const char *, char **, int)); extern double strtod PROTO((const char *, char **)); char *end; long x; double xx; errno = 0; end = s + strlen(s) - 1; if (*end == 'l' || *end == 'L') return long_scan(s, 0); if (s[0] == '0') x = (long) strtoul(s, &end, 0); else x = strtol(s, &end, 0); if (*end == '\0') { if (errno != 0) { err_setstr(OverflowError, "integer literal too large"); return NULL; } return newintobject(x); } errno = 0; xx = strtod(s, &end); if (*end == '\0') { #ifndef BROKEN_STRTOD /* Some strtod() versions (e.g., in older SunOS systems) set errno incorrectly; better to ignore overflows than not to be able to use float literals at all! */ if (errno != 0) { err_setstr(OverflowError, "float literal too large"); return NULL; } #endif return newfloatobject(xx); } err_setstr(SystemError, "bad number syntax?!?!"); return NULL; } static object * parsestr(s) char *s; { object *v; int len; char *buf; char *p; int c; int quote = *s; if (quote != '\'' && quote != '\"') { err_badcall(); return NULL; } s++; len = strlen(s); if (s[--len] != quote) { err_badcall(); return NULL; } if (strchr(s, '\\') == NULL) return newsizedstringobject(s, len); v = newsizedstringobject((char *)NULL, len); p = buf = getstringvalue(v); while (*s != '\0' && *s != '\'') { if (*s != '\\') { *p++ = *s++; continue; } s++; switch (*s++) { /* XXX This assumes ASCII! */ case '\\': *p++ = '\\'; break; case '\'': *p++ = '\''; break; case '\"': *p++ = '\"'; break; case 'b': *p++ = '\b'; break; case 'f': *p++ = '\014'; break; /* FF */ case 't': *p++ = '\t'; break; case 'n': *p++ = '\n'; break; case 'r': *p++ = '\r'; break; case 'v': *p++ = '\013'; break; /* VT */ case 'a': *p++ = '\007'; break; /* BEL, not classic C */ case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': c = s[-1] - '0'; if ('0' <= *s && *s <= '7') { c = (c<<3) + *s++ - '0'; if ('0' <= *s && *s <= '7') c = (c<<3) + *s++ - '0'; } *p++ = c; break; case 'x': if (isxdigit(*s)) { sscanf(s, "%x", &c); *p++ = c; do { s++; } while (isxdigit(*s)); break; } /* FALLTHROUGH */ default: *p++ = '\\'; *p++ = s[-1]; break; } } resizestring(&v, (int)(p - buf)); return v; } static void com_list_constructor(c, n) struct compiling *c; node *n; { int len; int i; if (TYPE(n) != testlist) REQ(n, exprlist); /* exprlist: expr (',' expr)* [',']; likewise for testlist */ len = (NCH(n) + 1) / 2; for (i = 0; i < NCH(n); i += 2) com_node(c, CHILD(n, i)); com_addoparg(c, BUILD_LIST, len); } static void com_dictmaker(c, n) struct compiling *c; node *n; { int i; /* dictmaker: test ':' test (',' test ':' value)* [','] */ for (i = 0; i+2 < NCH(n); i += 4) { /* We must arrange things just right for STORE_SUBSCR. It wants the stack to look like (value) (dict) (key) */ com_addbyte(c, DUP_TOP); com_node(c, CHILD(n, i+2)); /* value */ com_addbyte(c, ROT_TWO); com_node(c, CHILD(n, i)); /* key */ com_addbyte(c, STORE_SUBSCR); } } static void com_atom(c, n) struct compiling *c; node *n; { node *ch; object *v; int i; REQ(n, atom); ch = CHILD(n, 0); switch (TYPE(ch)) { case LPAR: if (TYPE(CHILD(n, 1)) == RPAR) com_addoparg(c, BUILD_TUPLE, 0); else com_node(c, CHILD(n, 1)); break; case LSQB: if (TYPE(CHILD(n, 1)) == RSQB) com_addoparg(c, BUILD_LIST, 0); else com_list_constructor(c, CHILD(n, 1)); break; case LBRACE: /* '{' [dictmaker] '}' */ com_addoparg(c, BUILD_MAP, 0); if (TYPE(CHILD(n, 1)) != RBRACE) com_dictmaker(c, CHILD(n, 1)); break; case BACKQUOTE: com_node(c, CHILD(n, 1)); com_addbyte(c, UNARY_CONVERT); break; case NUMBER: if ((v = parsenumber(STR(ch))) == NULL) { c->c_errors++; i = 255; } else { i = com_addconst(c, v); DECREF(v); } com_addoparg(c, LOAD_CONST, i); break; case STRING: if ((v = parsestr(STR(ch))) == NULL) { c->c_errors++; i = 255; } else { i = com_addconst(c, v); DECREF(v); } com_addoparg(c, LOAD_CONST, i); break; case NAME: com_addopname(c, LOAD_NAME, ch); break; default: fprintf(stderr, "node type %d\n", TYPE(ch)); err_setstr(SystemError, "com_atom: unexpected node type"); c->c_errors++; } } static void com_slice(c, n, op) struct compiling *c; node *n; int op; { if (NCH(n) == 1) { com_addbyte(c, op); } else if (NCH(n) == 2) { if (TYPE(CHILD(n, 0)) != COLON) { com_node(c, CHILD(n, 0)); com_addbyte(c, op+1); } else { com_node(c, CHILD(n, 1)); com_addbyte(c, op+2); } } else { com_node(c, CHILD(n, 0)); com_node(c, CHILD(n, 2)); com_addbyte(c, op+3); } } static void com_apply_subscript(c, n) struct compiling *c; node *n; { REQ(n, subscript); if (NCH(n) == 1 && TYPE(CHILD(n, 0)) != COLON) { /* It's a single subscript */ com_node(c, CHILD(n, 0)); com_addbyte(c, BINARY_SUBSCR); } else { /* It's a slice: [expr] ':' [expr] */ com_slice(c, n, SLICE); } } static void com_call_function(c, n) struct compiling *c; node *n; /* EITHER testlist OR ')' */ { if (TYPE(n) == RPAR) { com_addoparg(c, BUILD_TUPLE, 0); com_addbyte(c, BINARY_CALL); } else { REQ(n, testlist); com_list(c, n, 1); com_addbyte(c, BINARY_CALL); } } static void com_select_member(c, n) struct compiling *c; node *n; { com_addopname(c, LOAD_ATTR, n); } static void com_apply_trailer(c, n) struct compiling *c; node *n; { REQ(n, trailer); switch (TYPE(CHILD(n, 0))) { case LPAR: com_call_function(c, CHILD(n, 1)); break; case DOT: com_select_member(c, CHILD(n, 1)); break; case LSQB: com_apply_subscript(c, CHILD(n, 1)); break; default: err_setstr(SystemError, "com_apply_trailer: unknown trailer type"); c->c_errors++; } } static void com_factor(c, n) struct compiling *c; node *n; { int i; REQ(n, factor); if (TYPE(CHILD(n, 0)) == PLUS) { com_factor(c, CHILD(n, 1)); com_addbyte(c, UNARY_POSITIVE); } else if (TYPE(CHILD(n, 0)) == MINUS) { com_factor(c, CHILD(n, 1)); com_addbyte(c, UNARY_NEGATIVE); } else if (TYPE(CHILD(n, 0)) == TILDE) { com_factor(c, CHILD(n, 1)); com_addbyte(c, UNARY_INVERT); } else { com_atom(c, CHILD(n, 0)); for (i = 1; i < NCH(n); i++) com_apply_trailer(c, CHILD(n, i)); } } static void com_term(c, n) struct compiling *c; node *n; { int i; int op; REQ(n, term); com_factor(c, CHILD(n, 0)); for (i = 2; i < NCH(n); i += 2) { com_factor(c, CHILD(n, i)); switch (TYPE(CHILD(n, i-1))) { case STAR: op = BINARY_MULTIPLY; break; case SLASH: op = BINARY_DIVIDE; break; case PERCENT: op = BINARY_MODULO; break; default: err_setstr(SystemError, "com_term: operator not *, / or %"); c->c_errors++; op = 255; } com_addbyte(c, op); } } static void com_arith_expr(c, n) struct compiling *c; node *n; { int i; int op; REQ(n, arith_expr); com_term(c, CHILD(n, 0)); for (i = 2; i < NCH(n); i += 2) { com_term(c, CHILD(n, i)); switch (TYPE(CHILD(n, i-1))) { case PLUS: op = BINARY_ADD; break; case MINUS: op = BINARY_SUBTRACT; break; default: err_setstr(SystemError, "com_arith_expr: operator not + or -"); c->c_errors++; op = 255; } com_addbyte(c, op); } } static void com_shift_expr(c, n) struct compiling *c; node *n; { int i; int op; REQ(n, shift_expr); com_arith_expr(c, CHILD(n, 0)); for (i = 2; i < NCH(n); i += 2) { com_arith_expr(c, CHILD(n, i)); switch (TYPE(CHILD(n, i-1))) { case LEFTSHIFT: op = BINARY_LSHIFT; break; case RIGHTSHIFT: op = BINARY_RSHIFT; break; default: err_setstr(SystemError, "com_shift_expr: operator not << or >>"); c->c_errors++; op = 255; } com_addbyte(c, op); } } static void com_and_expr(c, n) struct compiling *c; node *n; { int i; int op; REQ(n, and_expr); com_shift_expr(c, CHILD(n, 0)); for (i = 2; i < NCH(n); i += 2) { com_shift_expr(c, CHILD(n, i)); if (TYPE(CHILD(n, i-1)) == AMPER) { op = BINARY_AND; } else { err_setstr(SystemError, "com_and_expr: operator not &"); c->c_errors++; op = 255; } com_addbyte(c, op); } } static void com_xor_expr(c, n) struct compiling *c; node *n; { int i; int op; REQ(n, xor_expr); com_and_expr(c, CHILD(n, 0)); for (i = 2; i < NCH(n); i += 2) { com_and_expr(c, CHILD(n, i)); if (TYPE(CHILD(n, i-1)) == CIRCUMFLEX) { op = BINARY_XOR; } else { err_setstr(SystemError, "com_xor_expr: operator not ^"); c->c_errors++; op = 255; } com_addbyte(c, op); } } static void com_expr(c, n) struct compiling *c; node *n; { int i; int op; REQ(n, expr); com_xor_expr(c, CHILD(n, 0)); for (i = 2; i < NCH(n); i += 2) { com_xor_expr(c, CHILD(n, i)); if (TYPE(CHILD(n, i-1)) == VBAR) { op = BINARY_OR; } else { err_setstr(SystemError, "com_expr: expr operator not |"); c->c_errors++; op = 255; } com_addbyte(c, op); } } static enum cmp_op cmp_type(n) node *n; { REQ(n, comp_op); /* comp_op: '<' | '>' | '=' | '>=' | '<=' | '<>' | '!=' | '==' | 'in' | 'not' 'in' | 'is' | 'is' not' */ if (NCH(n) == 1) { n = CHILD(n, 0); switch (TYPE(n)) { case LESS: return LT; case GREATER: return GT; case EQEQUAL: /* == */ case EQUAL: return EQ; case LESSEQUAL: return LE; case GREATEREQUAL: return GE; case NOTEQUAL: return NE; /* <> or != */ case NAME: if (strcmp(STR(n), "in") == 0) return IN; if (strcmp(STR(n), "is") == 0) return IS; } } else if (NCH(n) == 2) { switch (TYPE(CHILD(n, 0))) { case NAME: if (strcmp(STR(CHILD(n, 1)), "in") == 0) return NOT_IN; if (strcmp(STR(CHILD(n, 0)), "is") == 0) return IS_NOT; } } return BAD; } static void com_comparison(c, n) struct compiling *c; node *n; { int i; enum cmp_op op; int anchor; REQ(n, comparison); /* comparison: expr (comp_op expr)* */ com_expr(c, CHILD(n, 0)); if (NCH(n) == 1) return; /**************************************************************** The following code is generated for all but the last comparison in a chain: label: on stack: opcode: jump to: a a, b DUP_TOP a, b, b ROT_THREE b, a, b COMPARE_OP b, 0-or-1 JUMP_IF_FALSE L1 b, 1 POP_TOP b We are now ready to repeat this sequence for the next comparison in the chain. For the last we generate: b b, c COMPARE_OP 0-or-1 If there were any jumps to L1 (i.e., there was more than one comparison), we generate: 0-or-1 JUMP_FORWARD L2 L1: b, 0 ROT_TWO 0, b POP_TOP 0 L2: ****************************************************************/ anchor = 0; for (i = 2; i < NCH(n); i += 2) { com_expr(c, CHILD(n, i)); if (i+2 < NCH(n)) { com_addbyte(c, DUP_TOP); com_addbyte(c, ROT_THREE); } op = cmp_type(CHILD(n, i-1)); if (op == BAD) { err_setstr(SystemError, "com_comparison: unknown comparison op"); c->c_errors++; } com_addoparg(c, COMPARE_OP, op); if (i+2 < NCH(n)) { com_addfwref(c, JUMP_IF_FALSE, &anchor); com_addbyte(c, POP_TOP); } } if (anchor) { int anchor2 = 0; com_addfwref(c, JUMP_FORWARD, &anchor2); com_backpatch(c, anchor); com_addbyte(c, ROT_TWO); com_addbyte(c, POP_TOP); com_backpatch(c, anchor2); } } static void com_not_test(c, n) struct compiling *c; node *n; { REQ(n, not_test); /* 'not' not_test | comparison */ if (NCH(n) == 1) { com_comparison(c, CHILD(n, 0)); } else { com_not_test(c, CHILD(n, 1)); com_addbyte(c, UNARY_NOT); } } static void com_and_test(c, n) struct compiling *c; node *n; { int i; int anchor; REQ(n, and_test); /* not_test ('and' not_test)* */ anchor = 0; i = 0; for (;;) { com_not_test(c, CHILD(n, i)); if ((i += 2) >= NCH(n)) break; com_addfwref(c, JUMP_IF_FALSE, &anchor); com_addbyte(c, POP_TOP); } if (anchor) com_backpatch(c, anchor); } static void com_test(c, n) struct compiling *c; node *n; { int i; int anchor; REQ(n, test); /* and_test ('and' and_test)* */ anchor = 0; i = 0; for (;;) { com_and_test(c, CHILD(n, i)); if ((i += 2) >= NCH(n)) break; com_addfwref(c, JUMP_IF_TRUE, &anchor); com_addbyte(c, POP_TOP); } if (anchor) com_backpatch(c, anchor); } static void com_list(c, n, toplevel) struct compiling *c; node *n; int toplevel; /* If nonzero, *always* build a tuple */ { /* exprlist: expr (',' expr)* [',']; likewise for testlist */ if (NCH(n) == 1 && !toplevel) { com_node(c, CHILD(n, 0)); } else { int i; int len; len = (NCH(n) + 1) / 2; for (i = 0; i < NCH(n); i += 2) com_node(c, CHILD(n, i)); com_addoparg(c, BUILD_TUPLE, len); } } /* Begin of assignment compilation */ static void com_assign_name PROTO((struct compiling *, node *, int)); static void com_assign PROTO((struct compiling *, node *, int)); static void com_assign_attr(c, n, assigning) struct compiling *c; node *n; int assigning; { com_addopname(c, assigning ? STORE_ATTR : DELETE_ATTR, n); } static void com_assign_slice(c, n, assigning) struct compiling *c; node *n; int assigning; { com_slice(c, n, assigning ? STORE_SLICE : DELETE_SLICE); } static void com_assign_subscript(c, n, assigning) struct compiling *c; node *n; int assigning; { com_node(c, n); com_addbyte(c, assigning ? STORE_SUBSCR : DELETE_SUBSCR); } static void com_assign_trailer(c, n, assigning) struct compiling *c; node *n; int assigning; { REQ(n, trailer); switch (TYPE(CHILD(n, 0))) { case LPAR: /* '(' [exprlist] ')' */ err_setstr(SyntaxError, "can't assign to function call"); c->c_errors++; break; case DOT: /* '.' NAME */ com_assign_attr(c, CHILD(n, 1), assigning); break; case LSQB: /* '[' subscript ']' */ n = CHILD(n, 1); REQ(n, subscript); /* subscript: expr | [expr] ':' [expr] */ if (NCH(n) > 1 || TYPE(CHILD(n, 0)) == COLON) com_assign_slice(c, n, assigning); else com_assign_subscript(c, CHILD(n, 0), assigning); break; default: err_setstr(SystemError, "unknown trailer type"); c->c_errors++; } } static void com_assign_tuple(c, n, assigning) struct compiling *c; node *n; int assigning; { int i; if (TYPE(n) != testlist) REQ(n, exprlist); if (assigning) com_addoparg(c, UNPACK_TUPLE, (NCH(n)+1)/2); for (i = 0; i < NCH(n); i += 2) com_assign(c, CHILD(n, i), assigning); } static void com_assign_list(c, n, assigning) struct compiling *c; node *n; int assigning; { int i; if (assigning) com_addoparg(c, UNPACK_LIST, (NCH(n)+1)/2); for (i = 0; i < NCH(n); i += 2) com_assign(c, CHILD(n, i), assigning); } static void com_assign_name(c, n, assigning) struct compiling *c; node *n; int assigning; { REQ(n, NAME); com_addopname(c, assigning ? STORE_NAME : DELETE_NAME, n); } static void com_assign(c, n, assigning) struct compiling *c; node *n; int assigning; { /* Loop to avoid trivial recursion */ for (;;) { switch (TYPE(n)) { case exprlist: case testlist: if (NCH(n) > 1) { com_assign_tuple(c, n, assigning); return; } n = CHILD(n, 0); break; case test: case and_test: case not_test: case comparison: case expr: case xor_expr: case and_expr: case shift_expr: case arith_expr: case term: if (NCH(n) > 1) { err_setstr(SyntaxError, "can't assign to operator"); c->c_errors++; return; } n = CHILD(n, 0); break; case factor: /* ('+'|'-'|'~') factor | atom trailer* */ if (TYPE(CHILD(n, 0)) != atom) { /* '+'|'-'|'~' */ err_setstr(SyntaxError, "can't assign to operator"); c->c_errors++; return; } if (NCH(n) > 1) { /* trailer present */ int i; com_node(c, CHILD(n, 0)); for (i = 1; i+1 < NCH(n); i++) { com_apply_trailer(c, CHILD(n, i)); } /* NB i is still alive */ com_assign_trailer(c, CHILD(n, i), assigning); return; } n = CHILD(n, 0); break; case atom: switch (TYPE(CHILD(n, 0))) { case LPAR: n = CHILD(n, 1); if (TYPE(n) == RPAR) { /* XXX Should allow () = () ??? */ err_setstr(SyntaxError, "can't assign to ()"); c->c_errors++; return; } break; case LSQB: n = CHILD(n, 1); if (TYPE(n) == RSQB) { err_setstr(SyntaxError, "can't assign to []"); c->c_errors++; return; } com_assign_list(c, n, assigning); return; case NAME: com_assign_name(c, CHILD(n, 0), assigning); return; default: err_setstr(SyntaxError, "can't assign to literal"); c->c_errors++; return; } break; default: fprintf(stderr, "node type %d\n", TYPE(n)); err_setstr(SystemError, "com_assign: bad node"); c->c_errors++; return; } } } static void com_expr_stmt(c, n) struct compiling *c; node *n; { REQ(n, expr_stmt); /* testlist ('=' testlist)* */ com_node(c, CHILD(n, NCH(n)-1)); if (NCH(n) == 1) { com_addbyte(c, PRINT_EXPR); } else { int i; for (i = 0; i < NCH(n)-2; i+=2) { if (i+2 < NCH(n)-2) com_addbyte(c, DUP_TOP); com_assign(c, CHILD(n, i), 1/*assign*/); } } } static void com_print_stmt(c, n) struct compiling *c; node *n; { int i; REQ(n, print_stmt); /* 'print' (test ',')* [test] */ for (i = 1; i < NCH(n); i += 2) { com_node(c, CHILD(n, i)); com_addbyte(c, PRINT_ITEM); } if (TYPE(CHILD(n, NCH(n)-1)) != COMMA) com_addbyte(c, PRINT_NEWLINE); /* XXX Alternatively, LOAD_CONST '\n' and then PRINT_ITEM */ } static void com_return_stmt(c, n) struct compiling *c; node *n; { REQ(n, return_stmt); /* 'return' [testlist] */ if (!c->c_infunction) { err_setstr(SyntaxError, "'return' outside function"); c->c_errors++; } if (NCH(n) < 2) com_addoparg(c, LOAD_CONST, com_addconst(c, None)); else com_node(c, CHILD(n, 1)); com_addbyte(c, RETURN_VALUE); } static void com_raise_stmt(c, n) struct compiling *c; node *n; { REQ(n, raise_stmt); /* 'raise' test [',' test] */ com_node(c, CHILD(n, 1)); if (NCH(n) > 3) com_node(c, CHILD(n, 3)); else com_addoparg(c, LOAD_CONST, com_addconst(c, None)); com_addbyte(c, RAISE_EXCEPTION); } static void com_import_stmt(c, n) struct compiling *c; node *n; { int i; REQ(n, import_stmt); /* 'import' NAME (',' NAME)* | 'from' NAME 'import' ('*' | NAME (',' NAME)*) */ if (STR(CHILD(n, 0))[0] == 'f') { /* 'from' NAME 'import' ... */ REQ(CHILD(n, 1), NAME); com_addopname(c, IMPORT_NAME, CHILD(n, 1)); for (i = 3; i < NCH(n); i += 2) com_addopname(c, IMPORT_FROM, CHILD(n, i)); com_addbyte(c, POP_TOP); } else { /* 'import' ... */ for (i = 1; i < NCH(n); i += 2) { com_addopname(c, IMPORT_NAME, CHILD(n, i)); com_addopname(c, STORE_NAME, CHILD(n, i)); } } } static void com_global_stmt(c, n) struct compiling *c; node *n; { int i; REQ(n, global_stmt); /* 'global' NAME (',' NAME)* */ for (i = 1; i < NCH(n); i += 2) { if (dictinsert(c->c_globals, STR(CHILD(n, i)), None) != 0) c->c_errors++; } } #define strequ(a, b) (strcmp((a), (b)) == 0) static void com_access_stmt(c, n) struct compiling *c; node *n; { int i, j, k, mode, imode; object *vmode; REQ(n, access_stmt); /* 'access' NAME (',' NAME)* ':' accesstype (',' accesstype)* accesstype: NAME+ */ /* Find where the colon is */ i = 1; while (TYPE(CHILD(n,i-1)) != COLON) i += 1; /* Calculate the mode mask */ mode = 0; for (j = i; j < NCH(n); j += 2) { int r = 0, w = 0, p = 0; for (k = 0; k < NCH(CHILD(n,j)); k++) { if (strequ(STR(CHILD(CHILD(n,j),k)), "public")) p = 0; else if (strequ(STR(CHILD(CHILD(n,j),k)), "protected")) p = 1; else if (strequ(STR(CHILD(CHILD(n,j),k)), "private")) p = 2; else if (strequ(STR(CHILD(CHILD(n,j),k)), "read")) r = 1; else if (strequ(STR(CHILD(CHILD(n,j),k)), "write")) w = 1; else /* XXX should make this an exception */ fprintf(stderr, "bad access type %s\n", STR(CHILD(CHILD(n,j),k))); } if (r == 0 && w == 0) r = w = 1; if (p == 0) { if (r == 1) mode |= AC_R_PUBLIC; if (w == 1) mode |= AC_W_PUBLIC; } else if (p == 1) { if (r == 1) mode |= AC_R_PROTECTED; if (w == 1) mode |= AC_W_PROTECTED; } else { if (r == 1) mode |= AC_R_PRIVATE; if (w == 1) mode |= AC_W_PRIVATE; } } vmode = newintobject((long)mode); imode = com_addconst(c, vmode); XDECREF(vmode); for (i = 1; TYPE(CHILD(n,i-1)) != COLON; i+=2) { com_addoparg(c, LOAD_CONST, imode); com_addopname(c, ACCESS_MODE, CHILD(n, i)); } } static void com_exec_stmt(c, n) struct compiling *c; node *n; { REQ(n, exec_stmt); /* exec_stmt: 'exec' expr ['in' expr [',' expr]] */ com_node(c, CHILD(n, 1)); if (NCH(n) >= 4) com_node(c, CHILD(n, 3)); else com_addoparg(c, LOAD_CONST, com_addconst(c, None)); if (NCH(n) >= 6) com_node(c, CHILD(n, 5)); else com_addbyte(c, DUP_TOP); com_addbyte(c, EXEC_STMT); } static void com_if_stmt(c, n) struct compiling *c; node *n; { int i; int anchor = 0; REQ(n, if_stmt); /*'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite] */ for (i = 0; i+3 < NCH(n); i+=4) { int a = 0; node *ch = CHILD(n, i+1); if (i > 0) com_addoparg(c, SET_LINENO, ch->n_lineno); com_node(c, CHILD(n, i+1)); com_addfwref(c, JUMP_IF_FALSE, &a); com_addbyte(c, POP_TOP); com_node(c, CHILD(n, i+3)); com_addfwref(c, JUMP_FORWARD, &anchor); com_backpatch(c, a); com_addbyte(c, POP_TOP); } if (i+2 < NCH(n)) com_node(c, CHILD(n, i+2)); com_backpatch(c, anchor); } static void com_while_stmt(c, n) struct compiling *c; node *n; { int break_anchor = 0; int anchor = 0; int save_begin = c->c_begin; REQ(n, while_stmt); /* 'while' test ':' suite ['else' ':' suite] */ com_addfwref(c, SETUP_LOOP, &break_anchor); block_push(c, SETUP_LOOP); c->c_begin = c->c_nexti; com_addoparg(c, SET_LINENO, n->n_lineno); com_node(c, CHILD(n, 1)); com_addfwref(c, JUMP_IF_FALSE, &anchor); com_addbyte(c, POP_TOP); c->c_loops++; com_node(c, CHILD(n, 3)); c->c_loops--; com_addoparg(c, JUMP_ABSOLUTE, c->c_begin); c->c_begin = save_begin; com_backpatch(c, anchor); com_addbyte(c, POP_TOP); com_addbyte(c, POP_BLOCK); block_pop(c, SETUP_LOOP); if (NCH(n) > 4) com_node(c, CHILD(n, 6)); com_backpatch(c, break_anchor); } static void com_for_stmt(c, n) struct compiling *c; node *n; { object *v; int break_anchor = 0; int anchor = 0; int save_begin = c->c_begin; REQ(n, for_stmt); /* 'for' exprlist 'in' exprlist ':' suite ['else' ':' suite] */ com_addfwref(c, SETUP_LOOP, &break_anchor); block_push(c, SETUP_LOOP); com_node(c, CHILD(n, 3)); v = newintobject(0L); if (v == NULL) c->c_errors++; com_addoparg(c, LOAD_CONST, com_addconst(c, v)); XDECREF(v); c->c_begin = c->c_nexti; com_addoparg(c, SET_LINENO, n->n_lineno); com_addfwref(c, FOR_LOOP, &anchor); com_assign(c, CHILD(n, 1), 1/*assigning*/); c->c_loops++; com_node(c, CHILD(n, 5)); c->c_loops--; com_addoparg(c, JUMP_ABSOLUTE, c->c_begin); c->c_begin = save_begin; com_backpatch(c, anchor); com_addbyte(c, POP_BLOCK); block_pop(c, SETUP_LOOP); if (NCH(n) > 8) com_node(c, CHILD(n, 8)); com_backpatch(c, break_anchor); } /* Although 'execpt' and 'finally' clauses can be combined syntactically, they are compiled separately. In fact, try: S except E1: S1 except E2: S2 ... finally: Sf is equivalent to try: try: S except E1: S1 except E2: S2 ... finally: Sf meaning that the 'finally' clause is entered even if things go wrong again in an exception handler. Note that this is not the case for exception handlers: at most one is entered. Code generated for "try: S finally: Sf" is as follows: SETUP_FINALLY L POP_BLOCK LOAD_CONST L: END_FINALLY The special instructions use the block stack. Each block stack entry contains the instruction that created it (here SETUP_FINALLY), the level of the value stack at the time the block stack entry was created, and a label (here L). SETUP_FINALLY: Pushes the current value stack level and the label onto the block stack. POP_BLOCK: Pops en entry from the block stack, and pops the value stack until its level is the same as indicated on the block stack. (The label is ignored.) END_FINALLY: Pops a variable number of entries from the *value* stack and re-raises the exception they specify. The number of entries popped depends on the (pseudo) exception type. The block stack is unwound when an exception is raised: when a SETUP_FINALLY entry is found, the exception is pushed onto the value stack (and the exception condition is cleared), and the interpreter jumps to the label gotten from the block stack. Code generated for "try: S except E1, V1: S1 except E2, V2: S2 ...": (The contents of the value stack is shown in [], with the top at the right; 'tb' is trace-back info, 'val' the exception's associated value, and 'exc' the exception.) Value stack Label Instruction Argument [] SETUP_EXCEPT L1 [] [] POP_BLOCK [] JUMP_FORWARD L0 [tb, val, exc] L1: DUP ) [tb, val, exc, exc] ) [tb, val, exc, exc, E1] COMPARE_OP EXC_MATCH ) only if E1 [tb, val, exc, 1-or-0] JUMP_IF_FALSE L2 ) [tb, val, exc, 1] POP ) [tb, val, exc] POP [tb, val] (or POP if no V1) [tb] POP [] JUMP_FORWARD L0 [tb, val, exc, 0] L2: POP [tb, val, exc] DUP .............................etc....................... [tb, val, exc, 0] Ln+1: POP [tb, val, exc] END_FINALLY # re-raise exception [] L0: Of course, parts are not generated if Vi or Ei is not present. */ static void com_try_stmt(c, n) struct compiling *c; node *n; { int finally_anchor = 0; int except_anchor = 0; REQ(n, try_stmt); /* 'try' ':' suite (except_clause ':' suite)* | 'try' ':' 'finally' ':' suite */ /* XXX This can be simplified because except and finally can no longer be mixed in a single try statement */ if (NCH(n) > 3 && TYPE(CHILD(n, NCH(n)-3)) != except_clause) { /* Have a 'finally' clause */ com_addfwref(c, SETUP_FINALLY, &finally_anchor); block_push(c, SETUP_FINALLY); } if (NCH(n) > 3 && TYPE(CHILD(n, 3)) == except_clause) { /* Have an 'except' clause */ com_addfwref(c, SETUP_EXCEPT, &except_anchor); block_push(c, SETUP_EXCEPT); } com_node(c, CHILD(n, 2)); if (except_anchor) { int end_anchor = 0; int i; node *ch; com_addbyte(c, POP_BLOCK); block_pop(c, SETUP_EXCEPT); com_addfwref(c, JUMP_FORWARD, &end_anchor); com_backpatch(c, except_anchor); for (i = 3; i < NCH(n) && TYPE(ch = CHILD(n, i)) == except_clause; i += 3) { /* except_clause: 'except' [expr [',' expr]] */ if (except_anchor == 0) { err_setstr(SyntaxError, "default 'except:' must be last"); c->c_errors++; break; } except_anchor = 0; com_addoparg(c, SET_LINENO, ch->n_lineno); if (NCH(ch) > 1) { com_addbyte(c, DUP_TOP); com_node(c, CHILD(ch, 1)); com_addoparg(c, COMPARE_OP, EXC_MATCH); com_addfwref(c, JUMP_IF_FALSE, &except_anchor); com_addbyte(c, POP_TOP); } com_addbyte(c, POP_TOP); if (NCH(ch) > 3) com_assign(c, CHILD(ch, 3), 1/*assigning*/); else com_addbyte(c, POP_TOP); com_addbyte(c, POP_TOP); com_node(c, CHILD(n, i+2)); com_addfwref(c, JUMP_FORWARD, &end_anchor); if (except_anchor) { com_backpatch(c, except_anchor); com_addbyte(c, POP_TOP); } } com_addbyte(c, END_FINALLY); com_backpatch(c, end_anchor); } if (finally_anchor) { node *ch; com_addbyte(c, POP_BLOCK); block_pop(c, SETUP_FINALLY); block_push(c, END_FINALLY); com_addoparg(c, LOAD_CONST, com_addconst(c, None)); com_backpatch(c, finally_anchor); ch = CHILD(n, NCH(n)-1); com_addoparg(c, SET_LINENO, ch->n_lineno); com_node(c, ch); com_addbyte(c, END_FINALLY); block_pop(c, END_FINALLY); } } static void com_suite(c, n) struct compiling *c; node *n; { REQ(n, suite); /* simple_stmt | NEWLINE INDENT NEWLINE* (stmt NEWLINE*)+ DEDENT */ if (NCH(n) == 1) { com_node(c, CHILD(n, 0)); } else { int i; for (i = 0; i < NCH(n); i++) { node *ch = CHILD(n, i); if (TYPE(ch) == stmt) com_node(c, ch); } } } /* ARGSUSED */ static void com_continue_stmt(c, n) struct compiling *c; node *n; /* Not used, but passed for consistency */ { int i = c->c_nblocks; if (i-- > 0 && c->c_block[i] == SETUP_LOOP) { com_addoparg(c, JUMP_ABSOLUTE, c->c_begin); } else { err_setstr(SyntaxError, "'continue' not properly in loop"); c->c_errors++; } /* XXX Could allow it inside a 'finally' clause XXX if we could pop the exception still on the stack */ } static void com_funcdef(c, n) struct compiling *c; node *n; { object *v; REQ(n, funcdef); /* funcdef: 'def' NAME parameters ':' suite */ v = (object *)_compile(n, c->c_filename, 0); if (v == NULL) c->c_errors++; else { int i = com_addconst(c, v); com_addoparg(c, LOAD_CONST, i); com_addbyte(c, BUILD_FUNCTION); com_addopname(c, STORE_NAME, CHILD(n, 1)); DECREF(v); } } static void com_lambda(c, n) struct compiling *c; node *n; { object *v; REQ(n, lambda_input); v = (object *)_compile(n, c->c_filename, 1); if (v == NULL) c->c_errors++; else { int i = com_addconst(c, v); DECREF(v); com_addoparg(c, LOAD_CONST, i); com_addbyte(c, BUILD_FUNCTION); com_addbyte(c, RETURN_VALUE); } } static void com_bases(c, n) struct compiling *c; node *n; { int i; REQ(n, testlist); /* testlist: test (',' test)* [','] */ for (i = 0; i < NCH(n); i += 2) com_node(c, CHILD(n, i)); com_addoparg(c, BUILD_TUPLE, (NCH(n)+1) / 2); } static void com_classdef(c, n) struct compiling *c; node *n; { int i; object *v; REQ(n, classdef); /* classdef: class NAME ['(' testlist ')'] ':' suite */ if ((v = newstringobject(STR(CHILD(n, 1)))) == NULL) { c->c_errors++; return; } /* Push the class name on the stack */ i = com_addconst(c, v); com_addoparg(c, LOAD_CONST, i); DECREF(v); /* Push the tuple of base classes on the stack */ if (TYPE(CHILD(n, 2)) != LPAR) com_addoparg(c, BUILD_TUPLE, 0); else com_bases(c, CHILD(n, 3)); v = (object *)_compile(n, c->c_filename, 0); if (v == NULL) c->c_errors++; else { i = com_addconst(c, v); com_addoparg(c, LOAD_CONST, i); com_addbyte(c, BUILD_FUNCTION); com_addbyte(c, UNARY_CALL); com_addbyte(c, BUILD_CLASS); com_addopname(c, STORE_NAME, CHILD(n, 1)); DECREF(v); } } static void com_node(c, n) struct compiling *c; node *n; { switch (TYPE(n)) { /* Definition nodes */ case funcdef: com_funcdef(c, n); break; case classdef: com_classdef(c, n); break; /* Trivial parse tree nodes */ case stmt: case small_stmt: case flow_stmt: com_node(c, CHILD(n, 0)); break; case simple_stmt: /* small_stmt (';' small_stmt)* [';'] NEWLINE */ com_addoparg(c, SET_LINENO, n->n_lineno); { int i; for (i = 0; i < NCH(n)-1; i += 2) com_node(c, CHILD(n, i)); } break; case compound_stmt: com_addoparg(c, SET_LINENO, n->n_lineno); com_node(c, CHILD(n, 0)); break; /* Statement nodes */ case expr_stmt: com_expr_stmt(c, n); break; case print_stmt: com_print_stmt(c, n); break; case del_stmt: /* 'del' exprlist */ com_assign(c, CHILD(n, 1), 0/*delete*/); break; case pass_stmt: break; case break_stmt: if (c->c_loops == 0) { err_setstr(SyntaxError, "'break' outside loop"); c->c_errors++; } com_addbyte(c, BREAK_LOOP); break; case continue_stmt: com_continue_stmt(c, n); break; case return_stmt: com_return_stmt(c, n); break; case raise_stmt: com_raise_stmt(c, n); break; case import_stmt: com_import_stmt(c, n); break; case global_stmt: com_global_stmt(c, n); break; case access_stmt: com_access_stmt(c, n); break; case exec_stmt: com_exec_stmt(c, n); break; case if_stmt: com_if_stmt(c, n); break; case while_stmt: com_while_stmt(c, n); break; case for_stmt: com_for_stmt(c, n); break; case try_stmt: com_try_stmt(c, n); break; case suite: com_suite(c, n); break; /* Expression nodes */ case testlist: com_list(c, n, 0); break; case test: com_test(c, n); break; case and_test: com_and_test(c, n); break; case not_test: com_not_test(c, n); break; case comparison: com_comparison(c, n); break; case exprlist: com_list(c, n, 0); break; case expr: com_expr(c, n); break; case xor_expr: com_xor_expr(c, n); break; case and_expr: com_and_expr(c, n); break; case shift_expr: com_shift_expr(c, n); break; case arith_expr: com_arith_expr(c, n); break; case term: com_term(c, n); break; case factor: com_factor(c, n); break; case atom: com_atom(c, n); break; default: fprintf(stderr, "node type %d\n", TYPE(n)); err_setstr(SystemError, "com_node: unexpected node type"); c->c_errors++; } } static void com_fplist PROTO((struct compiling *, node *)); static void com_fpdef(c, n) struct compiling *c; node *n; { REQ(n, fpdef); /* fpdef: NAME | '(' fplist ')' */ if (TYPE(CHILD(n, 0)) == LPAR) com_fplist(c, CHILD(n, 1)); else com_addopname(c, STORE_NAME, CHILD(n, 0)); } static void com_fplist(c, n) struct compiling *c; node *n; { REQ(n, fplist); /* fplist: fpdef (',' fpdef)* [','] */ if (NCH(n) == 1) { com_fpdef(c, CHILD(n, 0)); } else { int i; com_addoparg(c, UNPACK_TUPLE, (NCH(n)+1)/2); for (i = 0; i < NCH(n); i += 2) com_fpdef(c, CHILD(n, i)); } } static void com_arglist(c, n) struct compiling *c; node *n; { int i, nargs, op; REQ(n, varargslist); /* varargslist: (fpdef ',')* '*' NAME | fpdef (',' fpdef)* [','] */ op = UNPACK_ARG; nargs = (NCH(n) + 1) / 2; for (i = 0; i < NCH(n); i += 2) { int t = TYPE(CHILD(n, i)); if (t == STAR) { op = UNPACK_VARARG; nargs = i/2; break; } } com_addoparg(c, op, nargs); for (i = 0; i < 2*nargs; i += 2) com_fpdef(c, CHILD(n, i)); if (op == UNPACK_VARARG) com_addopname(c, STORE_NAME, CHILD(n, 2*nargs+1)); } static void com_file_input(c, n) struct compiling *c; node *n; { int i; REQ(n, file_input); /* (NEWLINE | stmt)* ENDMARKER */ for (i = 0; i < NCH(n); i++) { node *ch = CHILD(n, i); if (TYPE(ch) != ENDMARKER && TYPE(ch) != NEWLINE) com_node(c, ch); } } /* Top-level compile-node interface */ static void compile_funcdef(c, n) struct compiling *c; node *n; { node *ch; REQ(n, funcdef); /* funcdef: 'def' NAME parameters ':' suite */ c->c_name = STR(CHILD(n, 1)); com_addoparg(c, RESERVE_FAST, com_addconst(c, None)); /* Patched! */ ch = CHILD(n, 2); /* parameters: '(' [varargslist] ')' */ ch = CHILD(ch, 1); /* ')' | varargslist */ if (TYPE(ch) == RPAR) com_addoparg(c, UNPACK_ARG, 0); else com_arglist(c, ch); c->c_infunction = 1; com_node(c, CHILD(n, 4)); c->c_infunction = 0; com_addoparg(c, LOAD_CONST, com_addconst(c, None)); com_addbyte(c, RETURN_VALUE); } static void compile_lambda(c, n) struct compiling *c; node *n; { REQ(n, lambda_input) com_arglist(c, CHILD(n, 0)); com_node(c, CHILD(n, 2)); com_addbyte(c, RETURN_VALUE); } static void compile_node(c, n) struct compiling *c; node *n; { com_addoparg(c, SET_LINENO, n->n_lineno); switch (TYPE(n)) { case single_input: /* One interactive command */ /* NEWLINE | simple_stmt | compound_stmt NEWLINE */ n = CHILD(n, 0); if (TYPE(n) != NEWLINE) com_node(c, n); com_addoparg(c, LOAD_CONST, com_addconst(c, None)); com_addbyte(c, RETURN_VALUE); break; case file_input: /* A whole file, or built-in function exec() */ com_file_input(c, n); com_addoparg(c, LOAD_CONST, com_addconst(c, None)); com_addbyte(c, RETURN_VALUE); break; case lambda_input: /* Built-in function lambda() */ (c->c_inlambda ? compile_lambda : com_lambda)(c, n); break; case eval_input: /* Built-in functions eval() and input() */ com_node(c, CHILD(n, 0)); com_addbyte(c, RETURN_VALUE); break; case funcdef: /* A function definition */ compile_funcdef(c, n); break; case classdef: /* A class definition */ /* classdef: 'class' NAME ['(' testlist ')'] ':' suite */ c->c_name = STR(CHILD(n, 1)); com_node(c, CHILD(n, NCH(n)-1)); /* The suite */ com_addbyte(c, LOAD_LOCALS); com_addbyte(c, RETURN_VALUE); break; default: fprintf(stderr, "node type %d\n", TYPE(n)); err_setstr(SystemError, "compile_node: unexpected node type"); c->c_errors++; } } /* Optimization for local variables in functions (and *only* functions). This replaces all LOAD_NAME, STORE_NAME and DELETE_NAME instructions that refer to local variables with LOAD_FAST etc. The latter instructions are much faster because they don't need to look up the variable name in a dictionary. To find all local variables, we check all STORE_NAME and IMPORT_FROM instructions. This yields all local variables, including arguments, function definitions, class definitions and import statements. (We don't check DELETE_NAME instructions, since if there's no STORE_NAME the DELETE_NAME will surely fail.) There is one problem: 'from foo import *' introduces local variables that we can't know while compiling. If this is the case, wo don't optimize at all (this rarely happens, since this form of import statement is mostly used at the module level). Note that, because of this optimization, code like the following won't work: eval('x = 1') print x NB: this modifies the string object co->co_code! */ static void optimize(c) struct compiling *c; { unsigned char *next_instr, *cur_instr; object *locals; int nlocals; int opcode; int oparg; object *name; int fast_reserved; object *error_type, *error_value; #define NEXTOP() (*next_instr++) #define NEXTARG() (next_instr += 2, (next_instr[-1]<<8) + next_instr[-2]) #define GETITEM(v, i) (getlistitem((v), (i))) #define GETNAMEOBJ(i) (GETITEM(c->c_names, (i))) locals = newdictobject(); if (locals == NULL) { c->c_errors++; return; } nlocals = 0; err_get(&error_type, &error_value); next_instr = (unsigned char *) getstringvalue(c->c_code); for (;;) { opcode = NEXTOP(); if (opcode == STOP_CODE) break; if (opcode == EXEC_STMT) goto end; /* Don't optimize if exec present */ if (HAS_ARG(opcode)) oparg = NEXTARG(); if (opcode == STORE_NAME || opcode == DELETE_NAME || opcode == IMPORT_FROM) { object *v; name = GETNAMEOBJ(oparg); if (dict2lookup(locals, name) != NULL) continue; err_clear(); v = newintobject(nlocals); if (v == NULL) { c->c_errors++; goto err; } nlocals++; if (dict2insert(locals, name, v) != 0) { DECREF(v); c->c_errors++; goto err; } DECREF(v); } } if (nlocals == 0 || dictlookup(locals, "*") != NULL) { /* Don't optimize anything */ goto end; } next_instr = (unsigned char *) getstringvalue(c->c_code); fast_reserved = 0; for (;;) { cur_instr = next_instr; opcode = NEXTOP(); if (opcode == STOP_CODE) break; if (HAS_ARG(opcode)) oparg = NEXTARG(); if (opcode == RESERVE_FAST) { int i = com_addconst(c, locals); cur_instr[1] = i & 0xff; cur_instr[2] = (i>>8) & 0xff; fast_reserved = 1; continue; } if (!fast_reserved) continue; if (opcode == LOAD_NAME || opcode == STORE_NAME || opcode == DELETE_NAME) { object *v; int i; name = GETNAMEOBJ(oparg); v = dict2lookup(locals, name); if (v == NULL) { err_clear(); continue; } i = getintvalue(v); switch (opcode) { case LOAD_NAME: cur_instr[0] = LOAD_FAST; break; case STORE_NAME: cur_instr[0] = STORE_FAST; break; case DELETE_NAME: cur_instr[0] = DELETE_FAST; break; } cur_instr[1] = i & 0xff; cur_instr[2] = (i>>8) & 0xff; } } end: err_setval(error_type, error_value); err: DECREF(locals); } codeobject * _compile(n, filename, inlambda) node *n; char *filename; int inlambda; { struct compiling sc; codeobject *co; if (!com_init(&sc, filename, inlambda)) return NULL; compile_node(&sc, n); com_done(&sc); if (TYPE(n) == funcdef && sc.c_errors == 0) optimize(&sc); co = NULL; if (sc.c_errors == 0) { object *v, *w; v = newstringobject(sc.c_filename); w = newstringobject(sc.c_name); if (v != NULL && w != NULL) co = newcodeobject(sc.c_code, sc.c_consts, sc.c_names, v, w); XDECREF(v); XDECREF(w); } com_free(&sc); return co; }