github.com/yanyiwu/go@v0.0.0-20150106053140-03d6637dbb7f/src/cmd/cc/macbody

// Inferno utils/cc/macbody
// http://code.google.com/p/inferno-os/source/browse/utils/cc/macbody
//
//	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
//	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
//	Portions Copyright © 1997-1999 Vita Nuova Limited
//	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
//	Portions Copyright © 2004,2006 Bruce Ellis
//	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
//	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
//	Portions Copyright © 2009 The Go Authors.  All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#define VARMAC 0x80

int32
getnsn(void)
{
	int32 n;
	int c;

	c = getnsc();
	if(c < '0' || c > '9')
		return -1;
	n = 0;
	while(c >= '0' && c <= '9') {
		n = n*10 + c-'0';
		c = getc();
	}
	unget(c);
	return n;
}

Sym*
getsym(void)
{
	int c;
	char *cp;

	c = getnsc();
	if(!isalpha(c) && c != '_' && c < 0x80) {
		unget(c);
		return S;
	}
	for(cp = symb;;) {
		if(cp <= symb+NSYMB-4)
			*cp++ = c;
		c = getc();
		if(isalnum(c) || c == '_' || c >= 0x80)
			continue;
		unget(c);
		break;
	}
	*cp = 0;
	if(cp > symb+NSYMB-4)
		yyerror("symbol too large: %s", symb);
	return lookup();
}

Sym*
getsymdots(int *dots)
{
	int c;
	Sym *s;

	s = getsym();
	if(s != S)
		return s;

	c = getnsc();
	if(c != '.'){
		unget(c);
		return S;
	}
	if(getc() != '.' || getc() != '.')
		yyerror("bad dots in macro");
	*dots = 1;
	return slookup("__VA_ARGS__");
}

int
getcom(void)
{
	int c;

	for(;;) {
		c = getnsc();
		if(c != '/')
			break;
		c = getc();
		if(c == '/') {
			while(c != '\n')
				c = getc();
			break;
		}
		if(c != '*')
			break;
		c = getc();
		for(;;) {
			if(c == '*') {
				c = getc();
				if(c != '/')
					continue;
				c = getc();
				break;
			}
			if(c == '\n') {
				yyerror("comment across newline");
				break;
			}
			c = getc();
		}
		if(c == '\n')
			break;
	}
	return c;
}

void
dodefine(char *cp)
{
	Sym *s;
	char *p;
	int32 l;

	ensuresymb(strlen(cp));
	strcpy(symb, cp);
	p = strchr(symb, '=');
	if(p) {
		*p++ = 0;
		s = lookup();
		l = strlen(p) + 2;	/* +1 null, +1 nargs */
		s->macro = alloc(l);
		strcpy(s->macro+1, p);
	} else {
		s = lookup();
		s->macro = "\0001";	/* \000 is nargs */
	}
	if(debug['m'])
		print("#define (-D) %s %s\n", s->name, s->macro+1);
}

struct
{
	char	*macname;
	void	(*macf)(void);
} mactab[] =
{
	"ifdef",	0,	/* macif(0) */
	"ifndef",	0,	/* macif(1) */
	"else",		0,	/* macif(2) */

	"line",		maclin,
	"define",	macdef,
	"include",	macinc,
	"undef",	macund,

	"pragma",	macprag,
	"endif",	macend,
	0
};

void
domacro(void)
{
	int i;
	Sym *s;

	s = getsym();
	if(s == S)
		s = slookup("endif");
	for(i=0; mactab[i].macname; i++)
		if(strcmp(s->name, mactab[i].macname) == 0) {
			if(mactab[i].macf)
				(*mactab[i].macf)();
			else
				macif(i);
			return;
		}
	yyerror("unknown #: %s", s->name);
	macend();
}

void
macund(void)
{
	Sym *s;

	s = getsym();
	macend();
	if(s == S) {
		yyerror("syntax in #undef");
		return;
	}
	s->macro = 0;
}

#define	NARG	25
void
macdef(void)
{
	Sym *s, *a;
	char *args[NARG], *np, *base;
	int n, i, c, len, dots;
	int ischr;

	s = getsym();
	if(s == S)
		goto bad;
	if(s->macro)
		yyerror("macro redefined: %s", s->name);
	c = getc();
	n = -1;
	dots = 0;
	if(c == '(') {
		n++;
		c = getnsc();
		if(c != ')') {
			unget(c);
			for(;;) {
				a = getsymdots(&dots);
				if(a == S)
					goto bad;
				if(n >= NARG) {
					yyerror("too many arguments in #define: %s", s->name);
					goto bad;
				}
				args[n++] = a->name;
				c = getnsc();
				if(c == ')')
					break;
				if(c != ',' || dots)
					goto bad;
			}
		}
		c = getc();
	}
	if(isspace(c))
		if(c != '\n')
			c = getnsc();
	base = hunk;
	len = 1;
	ischr = 0;
	for(;;) {
		if(isalpha(c) || c == '_') {
			np = symb;
			*np++ = c;
			c = getc();
			while(isalnum(c) || c == '_') {
				*np++ = c;
				c = getc();
			}
			*np = 0;
			for(i=0; i<n; i++)
				if(strcmp(symb, args[i]) == 0)
					break;
			if(i >= n) {
				i = strlen(symb);
				base = allocn(base, len, i);
				memcpy(base+len, symb, i);
				len += i;
				continue;
			}
			base = allocn(base, len, 2);
			base[len++] = '#';
			base[len++] = 'a' + i;
			continue;
		}
		if(ischr){
			if(c == '\\'){
				base = allocn(base, len, 1);
				base[len++] = c;
				c = getc();
			}else if(c == ischr)
				ischr = 0;
		}else{
			if(c == '"' || c == '\''){
				base = allocn(base, len, 1);
				base[len++] = c;
				ischr = c;
				c = getc();
				continue;
			}
			if(c == '/') {
				c = getc();
				if(c == '/'){
					c = getc();
					for(;;) {
						if(c == '\n')
							break;
						c = getc();
					}
					continue;
				}
				if(c == '*'){
					c = getc();
					for(;;) {
						if(c == '*') {
							c = getc();
							if(c != '/')
								continue;
							c = getc();
							break;
						}
						if(c == '\n') {
							yyerror("comment and newline in define: %s", s->name);
							break;
						}
						c = getc();
					}
					continue;
				}
				base = allocn(base, len, 1);
				base[len++] = '/';
				continue;
			}
		}
		if(c == '\\') {
			c = getc();
			if(c == '\n') {
				c = getc();
				continue;
			}
			else if(c == '\r') {
				c = getc();
				if(c == '\n') {
					c = getc();
					continue;
				}
			}
			base = allocn(base, len, 1);
			base[len++] = '\\';
			continue;
		}
		if(c == '\n')
			break;
		if(c == '#')
		if(n > 0) {
			base = allocn(base, len, 1);
			base[len++] = c;
		}
		base = allocn(base, len, 1);
		base[len++] = c;
		c = ((--fi.c < 0)? filbuf(): (*fi.p++ & 0xff));
		if(c == '\n')
			lineno++;
		if(c == -1) {
			yyerror("eof in a macro: %s", s->name);
			break;
		}
	}
	do {
		base = allocn(base, len, 1);
		base[len++] = 0;
	} while(len & 3);

	*base = n+1;
	if(dots)
		*base |= VARMAC;
	s->macro = base;
	if(debug['m'])
		print("#define %s %s\n", s->name, s->macro+1);
	return;

bad:
	if(s == S)
		yyerror("syntax in #define");
	else
		yyerror("syntax in #define: %s", s->name);
	macend();
}

void
macexpand(Sym *s, char *b)
{
	char buf[2000];
	int n, l, c, nargs;
	char *arg[NARG], *cp, *ob, *ecp, dots;

	ob = b;
	if(*s->macro == 0) {
		strcpy(b, s->macro+1);
		if(debug['m'])
			print("#expand %s %s\n", s->name, ob);
		return;
	}

	nargs = (char)(*s->macro & ~VARMAC) - 1;
	dots = *s->macro & VARMAC;

	c = getnsc();
	if(c != '(')
		goto bad;
	n = 0;
	c = getc();
	if(c != ')') {
		unget(c);
		l = 0;
		cp = buf;
		ecp = cp + sizeof(buf)-4;
		arg[n++] = cp;
		for(;;) {
			if(cp >= ecp)
				goto toobig;
			c = getc();
			if(c == '"')
				for(;;) {
					if(cp >= ecp)
						goto toobig;
					*cp++ = c;
					c = getc();
					if(c == '\\') {
						*cp++ = c;
						c = getc();
						continue;
					}
					if(c == '\n')
						goto bad;
					if(c == '"')
						break;
				}
			if(c == '\'')
				for(;;) {
					if(cp >= ecp)
						goto toobig;
					*cp++ = c;
					c = getc();
					if(c == '\\') {
						*cp++ = c;
						c = getc();
						continue;
					}
					if(c == '\n')
						goto bad;
					if(c == '\'')
						break;
				}
			if(c == '/') {
				c = getc();
				switch(c) {
				case '*':
					for(;;) {
						c = getc();
						if(c == '*') {
							c = getc();
							if(c == '/')
								break;
						}
					}
					*cp++ = ' ';
					continue;
				case '/':
					while((c = getc()) != '\n')
						;
					break;
				default:
					unget(c);
					c = '/';
				}
			}
			if(l == 0) {
				if(c == ',') {
					if(n == nargs && dots) {
						*cp++ = ',';
						continue;
					}
					*cp++ = 0;
					arg[n++] = cp;
					if(n > nargs)
						break;
					continue;
				}
				if(c == ')')
					break;
			}
			if(c == '\n')
				c = ' ';
			*cp++ = c;
			if(c == '(')
				l++;
			if(c == ')')
				l--;
		}
		*cp = 0;
	}
	if(n != nargs) {
		yyerror("argument mismatch expanding: %s", s->name);
		*b = 0;
		return;
	}
	cp = s->macro+1;
	for(;;) {
		c = *cp++;
		if(c == '\n')
			c = ' ';
		if(c != '#') {
			*b++ = c;
			if(c == 0)
				break;
			continue;
		}
		c = *cp++;
		if(c == 0)
			goto bad;
		if(c == '#') {
			*b++ = c;
			continue;
		}
		c -= 'a';
		if(c < 0 || c >= n)
			continue;
		strcpy(b, arg[c]);
		b += strlen(arg[c]);
	}
	*b = 0;
	if(debug['m'])
		print("#expand %s %s\n", s->name, ob);
	return;

bad:
	yyerror("syntax in macro expansion: %s", s->name);
	*b = 0;
	return;

toobig:
	yyerror("too much text in macro expansion: %s", s->name);
	*b = 0;
}

void
macinc(void)
{
	int c0, c, i, f;
	char str[STRINGSZ], *hp;

	c0 = getnsc();
	if(c0 != '"') {
		c = c0;
		if(c0 != '<')
			goto bad;
		c0 = '>';
	}
	for(hp = str;;) {
		c = getc();
		if(c == c0)
			break;
		if(c == '\n')
			goto bad;
		*hp++ = c;
	}
	*hp = 0;

	c = getcom();
	if(c != '\n')
		goto bad;

	f = -1;
	for(i=0; i<ninclude; i++) {
		if(i == 0 && c0 == '>')
			continue;
		ensuresymb(strlen(include[i])+strlen(str)+2);
		strcpy(symb, include[i]);
		strcat(symb, "/");
		if(strcmp(symb, "./") == 0)
			symb[0] = 0;
		strcat(symb, str);
		f = open(symb, OREAD);
		if(f >= 0)
			break;
	}
	if(f < 0)
		strcpy(symb, str);
	c = strlen(symb) + 1;
	hp = alloc(c);
	memcpy(hp, symb, c);
	newio();
	pushio();
	newfile(hp, f);
	return;

bad:
	unget(c);
	yyerror("syntax in #include");
	macend();
}

void
maclin(void)
{
	char *cp;
	int c;
	int32 n;

	n = getnsn();
	c = getc();
	if(n < 0)
		goto bad;

	for(;;) {
		if(c == ' ' || c == '\t') {
			c = getc();
			continue;
		}
		if(c == '"')
			break;
		if(c == '\n') {
			strcpy(symb, "<noname>");
			goto nn;
		}
		goto bad;
	}
	cp = symb;
	for(;;) {
		c = getc();
		if(c == '"')
			break;
		*cp++ = c;
	}
	*cp = 0;
	c = getcom();
	if(c != '\n')
		goto bad;

nn:
	c = strlen(symb) + 1;
	cp = alloc(c);
	memcpy(cp, symb, c);
	linklinehist(ctxt, lineno, cp, n);
	return;

bad:
	unget(c);
	yyerror("syntax in #line");
	macend();
}

void
macif(int f)
{
	int c, l, bol;
	Sym *s;

	if(f == 2)
		goto skip;
	s = getsym();
	if(s == S)
		goto bad;
	if(getcom() != '\n')
		goto bad;
	if((s->macro != 0) ^ f)
		return;

skip:
	bol = 1;
	l = 0;
	for(;;) {
		c = getc();
		if(c != '#') {
			if(!isspace(c))
				bol = 0;
			if(c == '\n')
				bol = 1;
			continue;
		}
		if(!bol)
			continue;
		s = getsym();
		if(s == S)
			continue;
		if(strcmp(s->name, "endif") == 0) {
			if(l) {
				l--;
				continue;
			}
			macend();
			return;
		}
		if(strcmp(s->name, "ifdef") == 0 || strcmp(s->name, "ifndef") == 0) {
			l++;
			continue;
		}
		if(l == 0 && f != 2 && strcmp(s->name, "else") == 0) {
			macend();
			return;
		}
	}

bad:
	yyerror("syntax in #if(n)def");
	macend();
}

void
macprag(void)
{
	Sym *s;
	int c0, c;
	char *hp;

	s = getsym();

	if(s && strcmp(s->name, "lib") == 0)
		goto praglib;
	if(s && strcmp(s->name, "pack") == 0) {
		pragpack();
		return;
	}
	if(s && strcmp(s->name, "fpround") == 0) {
		pragfpround();
		return;
	}
	if(s && strcmp(s->name, "textflag") == 0) {
		pragtextflag();
		return;
	}
	if(s && strcmp(s->name, "dataflag") == 0) {
		pragdataflag();
		return;
	}
	if(s && strcmp(s->name, "varargck") == 0) {
		pragvararg();
		return;
	}
	if(s && strcmp(s->name, "incomplete") == 0) {
		pragincomplete();
		return;
	}
	if(s && (strncmp(s->name, "cgo_", 4) == 0 || strncmp(s->name, "dyn", 3) == 0)) {
		pragcgo(s->name);
		return;
	}
	while(getnsc() != '\n')
		;
	return;

praglib:
	c0 = getnsc();
	if(c0 != '"') {
		c = c0;
		if(c0 != '<')
			goto bad;
		c0 = '>';
	}
	for(hp = symb;;) {
		c = getc();
		if(c == c0)
			break;
		if(c == '\n')
			goto bad;
		*hp++ = c;
	}
	*hp = 0;
	c = getcom();
	if(c != '\n')
		goto bad;

	/*
	 * put pragma-line in as a funny history
	 */
	c = strlen(symb) + 1;
	hp = alloc(c);
	memcpy(hp, symb, c);

	linklinehist(ctxt, lineno, hp, -1);
	return;

bad:
	unget(c);
	yyerror("syntax in #pragma lib");
	macend();
}

void
macend(void)
{
	int c;

	for(;;) {
		c = getnsc();
		if(c < 0 || c == '\n')
			return;
	}
}