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Avoid nested expansion of macros

Nested expansion of macros are inhibited to avoid infinite recursion.

--- a/cc1/cc1.h

+++ b/cc1/cc1.h

@@ -273,7 +273,7 @@

 extern unsigned short getfline(void);

 extern void setfname(char *name);

 extern void setfline(unsigned short line);

-extern char *addinput(char *fname);

+extern char *addinput(char *fname, Symbol *sym);

 extern void setnamespace(int ns);

 extern void setsafe(int type);

 #define accept(t) ((yytoken == (t)) ? next() : 0)

--- a/cc1/cpp.c

+++ b/cc1/cpp.c

@@ -170,7 +170,7 @@

 	if (!parsepars(buffer, arglist, atoi(s)))

 		return 0;

-	bp = addinput(NULL);

+	bp = addinput(NULL, sym);

 	len = INPUTSIZ-1;

 	for (s += 3; c = *s; ++s) {

 		if (c != '@') {

@@ -291,7 +291,7 @@

 }

 static char *

-mkdefine(char *s, Symbol *sym)

+mkdefine(char *s)

 {

 	int nargs;

 	char *args[NR_MACROARG], buff[LINESIZ+1];

@@ -304,9 +304,7 @@

 	if (*s != '\0')

 		s = copydefine(s, args, buff+3, LINESIZ-3, nargs);

-	sym->u.s = xstrdup(buff);

-

-	return s;

+	return xstrdup(buff);

 }

 static void

@@ -327,10 +325,11 @@

 	}

 	sym->flags |= ISDEFINED;

 	sym->ns = NS_CPP;

+	sym->ctx = UCHAR_MAX;

 	for (t = s + strlen(s) + 1; isspace(*--t); *t = '\0')

 		/* nothing */;

-	mkdefine(s, sym);

+	sym->u.s = mkdefine(s);

 	return;

 }

@@ -351,7 +350,7 @@

 	if (!string(&s, &file, delim))

 		goto bad_include;

 	cleanup(s);

-	if (delim == '"' && addinput(file))

+	if (delim == '"' && addinput(file, NULL))

 		return;

 	abort();

--- a/cc1/lex.c

+++ b/cc1/lex.c

@@ -19,6 +19,7 @@

 	unsigned short nline;

 	FILE *fp;

 	char *line, *begin, *p;

+	Symbol *macro;

 	struct input *next;

 };

@@ -33,7 +34,7 @@

 static Input *input;

 char *

-addinput(char *fname)

+addinput(char *fname, Symbol *sym)

 {

 	Input *ip;

 	FILE *fp;

@@ -58,6 +59,7 @@

 	ip = xmalloc(sizeof(Input));

 	ip->fname = fname;

 	ip->next = input;

+	ip->macro = sym;

 	ip->begin = ip->p = ip->line = xmalloc(INPUTSIZ);

 	*ip->begin = '\0';

 	ip->nline = nline;

@@ -389,7 +391,7 @@

 static unsigned

 iden(void)

 {

-	char *p;

+	char *p, *t, c;

 	for (p = input->p; isalnum(*p) || *p == '_'; ++p)

 		/* nothing */;

@@ -396,8 +398,29 @@

 	input->p = p;

 	tok2str();

 	yylval.sym = lookup(lex_ns);

-	if (yylval.sym->ns == NS_CPP && expand(yylval.sym))

-		return 0;

+	if (yylval.sym->ns == NS_CPP) {

+		Symbol *sym;

+

+		if (yylval.sym != input->macro && expand(yylval.sym))

+			return 0;

+		/*

+		 * it is not a correct macro call, so try to find

+		 * another definition. This is going to be expensive

+		 * but I think it is not going to be a common case.

+		 */

+		p = yylval.sym->name;

+		c = *p;

+		for (sym = yylval.sym->hash; sym; sym = sym->hash) {

+			t = sym->name;

+			if (c == *t && !strcmp(p, t)) {

+				yylval.sym = sym;

+				goto found_iden;

+			}

+		}

+		yylval.sym = install(lex_ns);

+		yylval.sym->flags &= ~ISDEFINED;

+	}

+found_iden:

 	if (yylval.sym->token != IDEN)

 		yylval.token = yylval.sym->u.token;

 	return yylval.sym->token;

--- a/cc1/main.c

+++ b/cc1/main.c

@@ -67,7 +67,7 @@

 	ikeywords();

-	if (!addinput(*argv))

+	if (!addinput(*argv, NULL))

 		die("error opening input file '%s'", *argv);

 	for (next(); yytoken != EOFTOK; extdecl())

 		/* nothing */;

--- a/cc1/stmt.c

+++ b/cc1/stmt.c

@@ -164,7 +164,7 @@

 	case TYPEIDEN:

 		/*

 		 * We cannot call to insert() because the call to lookup in

-	     * lex.c was done in NS_IDEN namespace, and it is impossibe

+		 * lex.c was done in NS_IDEN namespace, and it is impossibe

 		 * to fix this point, because an identifier at the beginning

 		 * of a statement may be part of an expression or part of a

 		 * label. This double call to lookup() is going to generate

--- a/cc1/symbol.c

+++ b/cc1/symbol.c

@@ -129,9 +129,16 @@

 		return yylval.sym;

 	}

-	h = &htab[hash(yytext)];

 	sym = newsym(ns);

 	sym->name = xstrdup(yytext);

+

+	if (yylval.sym->ns == NS_CPP) {

+		sym->hash = yylval.sym->hash;

+		yylval.sym->hash = sym;

+		return sym;

+	}

+

+	h = &htab[hash(yytext)];

 	sym->hash = *h;

 	*h = sym;

 	return sym;