shithub: scc

Info  •  Files  •  Log  •  Branches

cc1: Remove use of globals in macro expansion

The macro expansion proccess was depending too much of global variables,
which is also a problem because parameters of macros are also expanded,
and it means that the code must be reentrant.

--- a/src/cmd/cc/cc1/cpp.c

+++ b/src/cmd/cc/cc1/cpp.c

@@ -9,8 +9,18 @@

 #include <scc/scc.h>

 #include "cc1.h"

-static char *argp, *macroname;

-static unsigned arglen;

+struct macroctx {

+	char *name;

+	char *argp;

+	char **arglist;

+	char **listp;

+	char *buffer;

+	char *def;

+	size_t bufsiz;

+	int arglen;

+	int npars;

+};

+

 static unsigned ncmdlines;

 static Symbol *symline, *symfile;

 static unsigned char ifstatus[NR_COND];

@@ -94,33 +104,33 @@

 }

 static void

-nextcpp(void)

+nextcpp(struct macroctx *mp)

 {

 	next();

 	if (yytoken == EOFTOK)

 		error("unterminated argument list invoking macro \"%s\"",

-		      macroname);

-	if (yylen + 1 > arglen)

+		      mp->name);

+	if (yylen + 1 > mp->arglen)

 		error("argument overflow invoking macro \"%s\"",

-		      macroname);

+		      mp->name);

 	if (yytoken == IDEN)

 		yylval.sym->flags |= SUSED;

-	memcpy(argp, yytext, yylen);

-	argp += yylen;

-	*argp++ = ' ';

-	arglen -= yylen + 1;

+	memcpy(mp->argp, yytext, yylen);

+	mp->argp += yylen;

+	mp->arglen -= yylen + 1;

+	*mp->argp++ = ' ';

 }

 static void

-paren(void)

+paren(struct macroctx *mp)

 {

 	for (;;) {

-		nextcpp();

+		nextcpp(mp);

 		switch (yytoken) {

 		case ')':

 			return;

 		case '(':

-			paren();

+			paren(mp);

 			break;

 		}

 	}

@@ -127,18 +137,18 @@

 }

 static void

-parameter(void)

+parameter(struct macroctx *mp)

 {

 	for (;;) {

-		nextcpp();

+		nextcpp(mp);

 		switch (yytoken) {

 		case ')':

 		case ',':

-			argp -= 3;  /* remove " , "  or " ) "*/

-			*argp++ = '\0';

+			mp->argp -= 3;  /* remove " , "  or " ) "*/

+			*mp->argp++ = '\0';

 			return;

 		case '(':

-			paren();

+			paren(mp);

 			break;

 		}

 	}

@@ -145,25 +155,23 @@

 }

 static int

-parsepars(char *buffer, char **listp, int nargs)

+parsepars(struct macroctx *mp)

 {

 	int n;

-	if (nargs == -1)

+	if (mp->npars == -1)

 		return -1;

-	if (ahead() != '(' && nargs > 0)

+	if (ahead() != '(' && mp->npars > 0)

 		return 0;

 	next();

 	n = 0;

-	argp = buffer;

-	arglen = INPUTSIZ;

 	if (ahead() == ')') {

 		next();

 	} else {

 		do {

-			*listp++ = argp;

-			parameter();

+			*mp->listp++ = mp->argp;

+			parameter(mp);

 		} while (++n < NR_MACROARG && yytoken == ',');

 	}

 	if (yytoken != ')')

@@ -171,10 +179,10 @@

 	disexpand = 0;

 	if (n == NR_MACROARG)

-		error("too many parameters in macro \"%s\"", macroname);

-	if (n != nargs) {

+		error("too many parameters in macro \"%s\"", mp->name);

+	if (n != mp->npars) {

 		error("macro \"%s\" received %d arguments, but it takes %d",

-		      macroname, n, nargs);

+		      mp->name, n, mp->npars);

 	}

 	return 1;

@@ -181,13 +189,15 @@

 }

 static size_t

-copymacro(char *buffer, char *s, size_t bufsiz, char *arglist[])

+copymacro(struct macroctx *mp)

 {

 	int delim, c, esc;

-	char *p, *arg, *bp = buffer;

-	size_t size;

+	char *s, *p, *arg, *bp;

+	size_t size, bufsiz;

-	for (; c = *s; ++s) {

+	bp = mp->buffer;

+	bufsiz = mp->bufsiz;

+	for (s = mp->def; c = *s; ++s) {

 		switch (c) {

 		case '$':

 			while (bp[-1] == ' ')

@@ -219,7 +229,7 @@

 			bp += size;

 			break;

 		case '#':

-			arg = arglist[atoi(s += 2)];

+			arg = mp->arglist[atoi(s += 2)];

 			s += 2;

 			if (bufsiz < 3)

@@ -244,7 +254,7 @@

 			break;

 		case '@':

-			arg = arglist[atoi(++s)];

+			arg = mp->arglist[atoi(++s)];

 			s += 2;

 			size = strlen(arg);

@@ -263,10 +273,10 @@

 	}

 	*bp = '\0';

-	return bp - buffer;

+	return bp - mp->buffer;

 expansion_too_long:

-	error("macro expansion of \"%s\" too long", macroname);

+	error("macro expansion of \"%s\" too long", mp->name);

 }

 int

@@ -273,8 +283,8 @@

 expand(Symbol *sym)

 {

 	size_t elen;

-	int n, i;

-	char *s = sym->u.s;

+	int i;

+	struct macroctx macro;

 	char *arglist[NR_MACROARG];

 	char arguments[INPUTSIZ], buffer[INPUTSIZ];

@@ -283,7 +293,16 @@

 	if (disexpand || sym->hide)

 		return 0;

-	macroname = sym->name;

+	macro.name = sym->name;

+	macro.argp = arguments;

+	macro.listp = arglist;

+	macro.arglist = arglist;

+	macro.arglen = INPUTSIZ;

+	macro.buffer = buffer;

+	macro.npars = atoi(sym->u.s);

+	macro.def = sym->u.s + 3;

+	macro.bufsiz = INPUTSIZ-1;

+

 	if (sym == symfile) {

 		elen = sprintf(buffer, "\"%s\" ", filenam);

 		goto substitute;

@@ -292,20 +311,20 @@

 		elen = sprintf(buffer, "%d ", lineno);

 		goto substitute;

 	}

-	if (!s)

+	if (!sym->u.s)

 		return 1;

-	n = atoi(s);

-	if (!parsepars(arguments, arglist, n))

+	macro.npars = atoi(sym->u.s);

+	if (!parsepars(&macro))

 		return 0;

-	for (i = 0; i < n; ++i)

+	for (i = 0; i < macro.npars; ++i)

 		DBG("MACRO par%d:%s", i, arglist[i]);

-	elen = copymacro(buffer, s+3, INPUTSIZ-1, arglist);

+	elen = copymacro(&macro);

 substitute:

-	DBG("MACRO '%s' expanded to :'%s'", macroname, buffer);

 	buffer[elen] = '\0';

+	DBG("MACRO '%s' expanded to :'%s'", macro.name, buffer);

 	addinput(filenam, sym, xstrdup(buffer), FAIL);

 	return 1;