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[cc1] Add support for macro expansion in input buffers

We are going to implement the macro expansion using a push up/pop down of buffers.
It is important to keep a track of the symbol which generates the push up,
because this symbol becomes part of the hide set (see Prosser algorithm)
of the current expansion.

--- a/cc1/cc1.h

+++ b/cc1/cc1.h

@@ -307,6 +307,7 @@

 	Type *type;

 	unsigned short id;

 	unsigned char ctx;

+	unsigned char hide;

 	char ns;

 	unsigned char token;

 	short flags;

@@ -344,6 +345,7 @@

 struct input {

 	char *fname;

 	FILE *fp;

+	Symbol *hide;

 	char *line, *begin, *p;

 	struct input *next;

 	unsigned short nline;

@@ -392,7 +394,7 @@

 extern int moreinput(void);

 extern void expect(unsigned tok);

 extern void discard(void);

-extern int addinput(char *fname);

+extern int addinput(char *fname, Symbol *hide);

 extern void allocinput(char *fname, FILE *fp, char *line);

 extern void delinput(void);

 extern void setsafe(int type);

--- a/cc1/cpp.c

+++ b/cc1/cpp.c

@@ -238,14 +238,13 @@

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

 }

-#define BUFSIZE ((INPUTSIZ > FILENAME_MAX+2) ? INPUTSIZ : FILENAME_MAX+2)

 int

 expand(char *begin, Symbol *sym)

 {

-	size_t total, elen, rlen, llen, ilen;

+	size_t elen;

 	int n;

 	char *s = sym->u.s;

-	char *arglist[NR_MACROARG], arguments[INPUTSIZ], buffer[BUFSIZE];

+	char *arglist[NR_MACROARG], arguments[INPUTSIZ], buffer[INPUTSIZ];

 	macroname = sym->name;

 	if (sym == symfile) {

@@ -268,30 +267,12 @@

 substitute:

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

-	rlen = strlen(input->p);      /* rigth length */

-	llen = begin - input->line;   /* left length */

-	ilen = input->p - begin;      /* invocation length */

-	total = llen + elen + rlen;

-	if (total >= LINESIZ)

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

-

-	/* cut macro invocation */

-	memmove(begin, begin + ilen, rlen);

-

-	/* paste macro expansion */

-	memmove(begin + elen, begin, rlen);

-	memcpy(begin, buffer, elen);

-	input->line[total] = '\0';

-

-	input->p = input->begin = begin;

-

-	if (!(sym->flags & SDECLARED))

-		killsym(sym);

-

+	addinput(NULL, sym);

+	memcpy(input->line, buffer, elen);

+	input->line[elen] = '\0';

 	return 1;

 }

-#undef BUFSIZE

 static int

 getpars(Symbol *args[NR_MACROARG])

@@ -449,7 +430,7 @@

 	memcpy(path+dirlen, file, filelen);

 	path[dirlen + filelen] = '\0';

-	return addinput(path);

+	return addinput(path, NULL);

 }

 static void

--- a/cc1/lex.c

+++ b/cc1/lex.c

@@ -2,6 +2,7 @@

 static char sccsid[] = "@(#) ./cc1/lex.c";

 #include <ctype.h>

 #include <errno.h>

+#include <limits.h>

 #include <setjmp.h>

 #include <stdio.h>

 #include <stdlib.h>

@@ -85,18 +86,32 @@

 }

 int

-addinput(char *fname)

+addinput(char *fname, Symbol *hide)

 {

 	FILE *fp;

+	unsigned nline = 0;

-	if (fname) {

+	if (hide) {

+		/* this is a macro expansion */

+		fp = NULL;

+		fname = xstrdup(input->fname);

+		nline = input->nline;

+		if (hide->hide == UCHAR_MAX)

+			die("Too many macro expansions");

+		++hide->hide;

+	} else  if (fname) {

+		/* a new file */

 		if ((fp = fopen(fname, "r")) == NULL)

 			return 0;

 	} else {

+		/* reading from stdin */

 		fp = stdin;

 		fname = "<stdin>";

 	}

 	allocinput(fname, fp, NULL);

+	input->hide = hide;

+	input->nline = nline;

+

 	return 1;

 }

@@ -104,6 +119,7 @@

 delinput(void)

 {

 	Input *ip = input;

+	Symbol *hide = ip->hide;

 	if (ip->fp) {

 		if (fclose(ip->fp))

@@ -112,6 +128,17 @@

 		if (!ip->next)

 			eof = 1;

 	}

+	if (hide) {

+		--hide->hide;

+		/*

+		 * If the symbol is not declared then it was

+		 * an extension due to a #if directive with

+		 * a non declared symbol (expanded to 0),

+		 * thus we have to kill the symbol

+		 */

+		if ((hide->flags & SDECLARED) == 0)

+			killsym(hide);

+	}

 	if (eof)

 		return;

 	input = ip->next;

@@ -179,14 +206,21 @@

 	char *bp, *lim;

 	char c, peekc = 0;

-repeat:

+repeat_from_file:

 	input->begin = input->p = input->line;

 	*input->line = '\0';

+

+repeat_from_expand:

 	if (eof)

 		return 0;

+

+	if (!input->fp) {

+		delinput();

+		goto repeat_from_expand;

+	}

 	if (feof(input->fp)) {

 		delinput();

-		goto repeat;

+		goto repeat_from_file;

 	}

 	lim = &input->line[INPUTSIZ-1];

 	for (bp = input->line; bp < lim; *bp++ = c) {

@@ -213,8 +247,10 @@

 	static char file[FILENAME_MAX];

 	static unsigned nline;

 	char *s;

+	int wasexpand;

 repeat:

+	wasexpand = input->hide != NULL;

 	if (!readline())

 		return 0;

 	while (isspace(*input->p))

@@ -225,7 +261,7 @@

 		goto repeat;

 	}

-	if (onlycpp) {

+	if (onlycpp && !wasexpand) {

 		putchar('\n');

 		if (strcmp(file, input->fname)) {

 			strcpy(file, input->fname);

@@ -497,7 +533,7 @@

 	input->p = p;

 	tok2str();

 	if ((sym = lookup(NS_CPP, yytext, NOALLOC)) != NULL) {

-		if (!disexpand && expand(begin, sym))

+		if (!disexpand && !sym->hide && expand(begin, sym))

 			return next();

 	}

 	sym = lookup(namespace, yytext, ALLOC);

--- a/cc1/main.c

+++ b/cc1/main.c

@@ -102,7 +102,7 @@

 	for (i = 0; i < uflags.n; ++i)

 		undefmacro(uflags.s[i]);

-	if (!addinput(*argv)) {

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

 		die("error: failed to open input file '%s': %s",

 		    *argv, strerror(errno));

 	}

--- a/cc1/symbol.c

+++ b/cc1/symbol.c

@@ -152,6 +152,7 @@

 		name = xstrdup(name);

 	sym->name = name;

 	sym->id = 0;

+	sym->hide = 0;

 	sym->ns = ns;

 	sym->ctx = (ns == NS_CPP) ? UCHAR_MAX : curctx;

 	sym->token = IDEN;