ack/lang/cem/cemcom.ansi/LLlex.c

/*
 * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
 * See the copyright notice in the ACK home directory, in the file "Copyright".
 */
/* $Id$ */
/*		    L E X I C A L   A N A L Y Z E R			*/

#include	<assert.h>
#include	<alloc.h>
#include    "parameters.h"
#include	"input.h"
#include	"arith.h"
#include	"def.h"
#include	"macro.h"
#include	"idf.h"
#include	"LLlex.h"
#include	"Lpars.h"
#include	"class.h"
#include	"sizes.h"
#include	"specials.h"	/* registration of special identifiers */

/* Data about the token yielded */
struct token dot, ahead, aside;
int token_nmb = 0;		/* number of the ahead token */
int tk_nmb_at_last_syn_err = -5/*ERR_SHADOW*/;
				/* token number at last syntax error */
int idfsize = IDFSIZE;
char sp_occurred[SP_TOTAL+1];

#ifndef	NOPP
int ReplaceMacros = 1;		/* replacing macros			*/
int AccDefined = 0;		/* accept "defined(...)"		*/
int UnknownIdIsZero = 0;	/* interpret unknown id as integer 0	*/
int Unstacked = 0;		/* an unstack is done 			*/
extern int InputLevel;
#endif
int AccFileSpecifier = 0;	/* return filespecifier <...>		*/
int EoiForNewline = 0;		/* return EOI upon encountering newline	*/
int File_Inserted = 0;		/* a file has just been inserted	*/
int LexSave = 0;		/* last character read by GetChar	*/
#define	MAX_LL_DEPTH	2

#define	FLG_ESEEN	0x01	/* possibly a floating point number */
#define	FLG_DOTSEEN	0x02	/* certainly a floating point number */
extern arith full_mask[];

#ifdef LINT
extern int lint_skip_comment;
#endif

#ifndef	NOPP
static struct token LexStack[MAX_LL_DEPTH];
static LexSP = 0;

void skipcomment();

/*	In PushLex() the actions are taken in order to initialise or
	re-initialise the lexical scanner.
	E.g. at the invocation of a sub-parser that uses LLlex(), the
	state of the current parser should be saved.
*/
PushLex()
{
	assert(LexSP < MAX_LL_DEPTH);
	assert(ASIDE == 0);	/* ASIDE = 0;	*/
	GetToken(&ahead);
	LexStack[LexSP++] = dot;
}

PopLex()
{
	assert(LexSP > 0);
	dot = LexStack[--LexSP];
}
#endif	/* NOPP */

int
LLlex()
{
	/*	LLlex() plays the role of Lexical Analyzer for the C parser.
		The look-ahead and putting aside of tokens are taken into
		account.
	*/
	if (ASIDE) {	/* a token is put aside		*/
		dot = aside;
		ASIDE = 0;
	}
	else {		/* read ahead and return the old one	*/
#ifdef	LINT
		lint_comment_ahead();
#endif	/* LINT */
		dot = ahead;
		/*	the following test is performed due to the dual
			task of LLlex(): it is also called for parsing the
			restricted constant expression following a #if or
			#elif.  The newline character causes EOF to be
			returned in this case to stop the LLgen parsing task.
		*/
		if (DOT != EOI)
			GetToken(&ahead);
		else
			DOT = EOF;
	}
	return DOT;
}


char	*string_token();
arith	char_constant();

int
GetToken(ptok)
	register struct token *ptok;
{
	/*	GetToken() is the actual token recognizer. It calls the
		control line interpreter if it encounters a "\n{w}*#"
		combination. Macro replacement is also performed if it is
		needed.
	*/
	char buf[(IDFSIZE > NUMSIZE ? IDFSIZE : NUMSIZE) + 1];
	register int ch, nch;

	token_nmb++;

	if (File_Inserted) {
		File_Inserted = 0;
		goto firstline;
	}

again:	/* rescan the input after an error or replacement	*/
	ch = GetChar();
go_on:	/* rescan, the following character has been read	*/
	if ((ch & 0200) && ch != EOI) /* stop on non-ascii character */
	{
		fatal("non-ascii '\\%03o' read", ch & 0377);
	}
	/* keep track of the place of the token in the file	*/
	ptok->tk_file = FileName;
	ptok->tk_line = LineNumber;

	switch (class(ch)) {	/* detect character class	*/
	case STNL:		/* newline, vertical space or formfeed	*/
firstline:
		LineNumber++;			/* also at vs and ff	*/
		ptok->tk_file = FileName;
		ptok->tk_line = LineNumber;
		if (EoiForNewline)	/* called in control line	*/
			/*	a newline in a control line indicates the
				end-of-information of the line.
			*/
			return ptok->tk_symb = EOI;

		while ((ch = GetChar()),
			(ch == '#'
#ifndef NOPP
			|| ch == '/'
#endif
			|| class(ch) == STSKIP)) {
			/* blanks are allowed before hashes */
			if (ch == '#') {
				/* a control line follows */
				domacro();
#ifndef	NOPP
				if (File_Inserted) {
					File_Inserted = 0;
					goto firstline;
				}
			} else if (ch == '/') {
				if ((GetChar() == '*') && !InputLevel) {
					skipcomment();
				} else {
					UnGetChar();
					break;
				}
#endif	/* NOPP */
			}
		}
			/*	We have to loop here, because in
				`domacro' the nl, vt or ff is read. The
				character following it may again be a `#'.
			*/
		goto go_on;
	case STSKIP:		/* just skip the skip characters	*/
		goto again;
	case STGARB:		/* garbage character			*/
#ifndef	NOPP
garbage:
#endif
		if (040 < ch && ch < 0177) {
			return ptok->tk_symb = ch;
		} else {
			lexerror("garbage char \\%03o", ch);
		}
		goto again;
	case STSIMP:	/* a simple character, no part of compound token*/
		return ptok->tk_symb = ch;
	case STCOMP:	/* maybe the start of a compound token		*/
		nch = GetChar();		/* character lookahead	*/
		switch (ch) {
		case '!':
			if (nch == '=')
				return ptok->tk_symb = NOTEQUAL;
			break;
		case '&':
			if (nch == '&')
				return ptok->tk_symb = AND;
			if (nch == '=')
				return ptok->tk_symb = ANDAB;
			break;
		case '+':
			if (nch == '+')
				return ptok->tk_symb = PLUSPLUS;
			if (nch == '=')
				return ptok->tk_symb = PLUSAB;
			break;
		case '-':
			if (nch == '-')
				return ptok->tk_symb = MINMIN;
			if (nch == '>')
				return ptok->tk_symb = ARROW;
			if (nch == '=')
				return ptok->tk_symb = MINAB;
			break;
		case '<':
			if (AccFileSpecifier) {
				UnGetChar();	/* pushback nch */
				ptok->tk_bts = string_token("file specifier",
							'>', &(ptok->tk_len));
				return ptok->tk_symb = FILESPECIFIER;
			}
			if (nch == '<') {
				if ((nch = GetChar()) == '=')
					return ptok->tk_symb = LEFTAB;
				UnGetChar();
				return ptok->tk_symb = LEFT;
			}
			if (nch == '=')
				return ptok->tk_symb = LESSEQ;
			break;
		case '=':
			if (nch == '=')
				return ptok->tk_symb = EQUAL;
			break;
		case '>':
			if (nch == '=')
				return ptok->tk_symb = GREATEREQ;
			if (nch == '>') {
				if ((nch = GetChar()) == '=')
					return ptok->tk_symb = RIGHTAB;
				UnGetChar();
				return ptok->tk_symb = RIGHT;
			}
			break;
		case '|':
			if (nch == '|')
				return ptok->tk_symb = OR;
			if (nch == '=')
				return ptok->tk_symb = ORAB;
			break;
		case '%':
			if (nch == '=')
				return ptok->tk_symb = MODAB;
			break;
		case '*':
			if (nch == '=')
				return ptok->tk_symb = TIMESAB;
			break;
		case '^':
			if (nch == '=')
				return ptok->tk_symb = XORAB;
			break;
		case '/':
#ifndef	NOPP
			if (nch == '*' && !InputLevel) {
				skipcomment();
				goto again;
			}
#endif
			if (nch == '=')
				return ptok->tk_symb = DIVAB;
			break;
		default:
			crash("bad class for char 0%o", ch);
			/* NOTREACHED */
		}
		UnGetChar();
		return ptok->tk_symb = ch;
	case STCHAR:				/* character constant	*/
		ptok->tk_ival = char_constant("character");
		ptok->tk_fund = INT;
		return ptok->tk_symb = INTEGER;
	case STSTR:					/* string	*/
		ptok->tk_bts = string_token("string", '"', &(ptok->tk_len));
		ptok->tk_fund = CHAR;		/* string of characters */
		return ptok->tk_symb = STRING;
	case STELL:		/* wide character constant/string prefix */
		nch = GetChar();
		if (nch == '"') {
			ptok->tk_bts = string_token("wide character string",
					'"', &(ptok->tk_len));
			ptok->tk_fund = WCHAR;	/* string of wide characters */
			return ptok->tk_symb = STRING;
		} else if (nch == '\'') {
			ptok->tk_ival = char_constant("wide character");
			ptok->tk_fund = INT;
			return ptok->tk_symb = INTEGER;
		}
		UnGetChar();
		/* fallthrough */
	case STIDF:
	{
		register char *tg = &buf[0];
		register int pos = -1;
		register struct idf *idef;
		extern int idfsize;		/* ??? */
#ifndef	NOPP
		int NoExpandNext = 0;

		if (Unstacked) EnableMacros();	/* unstack macro's when allowed. */
		if (ch == NOEXPM)  {
			NoExpandNext = 1;
			ch = GetChar();
		}
#endif
		do	{			/* read the identifier	*/
			if (++pos < idfsize) {
				*tg++ = ch;
			}
			ch = GetChar();
		} while (in_idf(ch));

		if (ch != EOI)
			UnGetChar();
		*tg++ = '\0';	/* mark the end of the identifier	*/
		idef = ptok->tk_idf = str2idf(buf, 1);
		sp_occurred[idef->id_special] = 1;
		idef->id_file = ptok->tk_file;
		idef->id_line = ptok->tk_line;
#ifndef	NOPP
		if (idef->id_macro && ReplaceMacros && !NoExpandNext) {
			if (replace(idef))
					goto again;
		}
		if (UnknownIdIsZero && idef->id_reserved != SIZEOF) {
			ptok->tk_ival = (arith)0;
			ptok->tk_fund = INT;
			return ptok->tk_symb = INTEGER;
		}
#endif /* NOPP */
		ptok->tk_symb = (
			idef->id_reserved
			    ? idef->id_reserved
			    : idef->id_def && idef->id_def->df_sc == TYPEDEF
				? TYPE_IDENTIFIER
				: IDENTIFIER
		);
		return IDENTIFIER;
	}
	case STNUM:				/* a numeric constant	*/
	{
		register int siz_left = NUMSIZE - 1;
		register char *np = &buf[0];
		int flags = 0;

#define	store(ch)	if (--siz_left >= 0)		\
				*np++ = ch;

		if (ch == '.') {
			/*	An embarrasing ambiguity. We have either a
				pp-number, a field operator, an ELLIPSIS or
				an error (..).
			*/
			ch = GetChar();
			if (!is_dig(ch)) {	/* . or ... */
				if (ch == '.') {
					if ((ch = GetChar()) == '.')
						return ptok->tk_symb = ELLIPSIS;
					UnGetChar();		/* not '.' */
					ChPushBack('.');	/* sigh ... */
				} else
					UnGetChar();		/* not '.' */
				return ptok->tk_symb = '.';
			}
			UnGetChar();
			ch = '.';
			flags |= FLG_DOTSEEN;
		 }
		store(ch);
		ch = GetChar();
		while(in_idf(ch) || ch == '.') {
			store(ch);
			if (ch == '.') flags |= FLG_DOTSEEN;
			if (ch == 'e' || ch == 'E') {
				flags |= FLG_ESEEN;
				ch = GetChar();
				if (ch == '+' || ch == '-') {
					flags |= FLG_DOTSEEN;	/* trick */
					store(ch);
					ch = GetChar();
				}
			} else ch = GetChar();
		}
		store('\0');
		UnGetChar();

		np = &buf[0];
		ch = *np++;
		if (siz_left < 0) {
			lexerror("number too long");
			if ((flags & FLG_DOTSEEN)
			    || (flags & FLG_ESEEN
				&& !(ch == '0'
				    && (*np == 'x' || *np == 'X')))) {
			    ptok->tk_fval = Salloc("0.0", (unsigned) 4);
			    ptok->tk_fund = DOUBLE;
			    return ptok->tk_symb = FLOATING;
			}
			ptok->tk_ival = 1;
			ptok->tk_fund = ULONG;
			ptok->tk_symb = INTEGER;
		}
		/* Now, the pp-number must be converted into a token */
		if ((flags & FLG_DOTSEEN)
			|| (flags & FLG_ESEEN
			    && !(ch == '0' && (*np == 'x' || *np == 'X')))) {
			strflt2tok(&buf[0], ptok);
			return ptok->tk_symb = FLOATING;
		}
		strint2tok(&buf[0], ptok);
		return ptok->tk_symb = INTEGER;
	}
	case STEOI:			/* end of text on source file	*/
		return ptok->tk_symb = EOI;
#ifndef	NOPP
	case STMSPEC:
		if (!InputLevel) goto garbage;
		if (ch == TOKSEP) goto again;
		/* fallthrough shouldn't happen */
#endif
	default:				/* this cannot happen	*/
		crash("bad class for char 0%o", ch);
	}
	/*NOTREACHED*/
}

#ifndef	NOPP
void
skipcomment()
{
	/*	The last character read has been the '*' of '/_*'.  The
		characters, except NL and EOI, between '/_*' and the first
		occurring '*_/' are not interpreted.
		NL only affects the LineNumber.  EOI is not legal.

		Important note: it is not possible to stop skipping comment
		beyond the end-of-file of an included file.
		EOI is returned by LoadChar only on encountering EOF of the
		top-level file...
	*/
	register int c, oldc = '\0';

	NoUnstack++;
	c = GetChar();
#ifdef	LINT
	if (! lint_skip_comment) {
		lint_start_comment();
		lint_comment_char(c);
	}
#endif	/* LINT */
	do {
		while (c != '*') {
			if (class(c) == STNL) {
				++LineNumber;
			} else if (c == EOI) {
				NoUnstack--;
#ifdef	LINT
				if (! lint_skip_comment) lint_end_comment();
#endif	/* LINT */
				return;
			}
			oldc = c;
			c = GetChar();
#ifdef	LINT
			if (! lint_skip_comment) lint_comment_char(c);
#endif	/* LINT */
		} /* last Character seen was '*' */
		c = GetChar();
		if ( c != '/' && oldc == '/')
			lexwarning("comment inside comment ?");
		oldc = '*';
#ifdef	LINT
		if (! lint_skip_comment) lint_comment_char(c);
#endif	/* LINT */
	} while (c != '/');
#ifdef	LINT
	if (! lint_skip_comment) lint_end_comment();
#endif	/* LINT */
	NoUnstack--;
}
#endif	/* NOPP */

arith
char_constant(nm)
	char *nm;
{
	register arith val = 0;
	register int ch;
	int size = 0;

	ch = GetChar();
	if (ch == '\'')
		lexerror("%s constant too short", nm);
	else
	while (ch != '\'') {
		if (ch == '\n') {
			lexerror("newline in %s constant", nm);
			LineNumber++;
			break;
		}
		if (ch == '\\')
			ch = quoted(GetChar());
		if (ch >= 128) ch -= 256;
		if (size < (int)int_size)
			val |= ch << 8 * size;
		size++;
		ch = GetChar();
	}
	if (size > 1)
		lexstrict("%s constant includes more than one character", nm);
	if (size > (int)int_size)
		lexerror("%s constant too long", nm);
	return val;
}

char *
string_token(nm, stop_char, plen)
	char *nm;
	int *plen;
{
	register int ch;
	register int str_size;
	register char *str = Malloc((unsigned) (str_size = ISTRSIZE));
	register int pos = 0;
	
	ch = GetChar();
	while (ch != stop_char) {
		if (ch == '\n') {
			lexerror("newline in %s", nm);
			LineNumber++;
			break;
		}
		if (ch == EOI) {
			lexerror("end-of-file inside %s", nm);
			break;
		}
		if (ch == '\\' && !AccFileSpecifier)
			ch = quoted(GetChar());
		str[pos++] = ch;
		if (pos == str_size)
			str = Realloc(str, (unsigned) (str_size += RSTRSIZE));
		ch = GetChar();
	}
	str[pos++] = '\0'; /* for filenames etc. */
	*plen = pos;
	return str;
}

int
quoted(ch)
	register int ch;
{	
	/*	quoted() replaces an escaped character sequence by the
		character meant.
	*/
	/* first char after backslash already in ch */
	if (!is_oct(ch)) {		/* a quoted char */
		switch (ch) {
		case 'n':
			ch = '\n';
			break;
		case 't':
			ch = '\t';
			break;
		case 'b':
			ch = '\b';
			break;
		case 'r':
			ch = '\r';
			break;
		case 'f':
			ch = '\f';
			break;
		case 'a':		/* alert */
			ch = '\007';
			break;
		case 'v':		/* vertical tab */
			ch = '\013';
			break;
		case 'x':		/* quoted hex */
		{
			register int hex = 0;
			register int vch;

			for (;;) {
				ch = GetChar();
				if ((vch = hex_val(ch)) == -1)
					break;
				hex = hex * 16 + vch;
			}
			UnGetChar();
			ch = hex;
		}
		}
	}
	else {				/* a quoted octal */
		register int oct = 0, cnt = 0;

		do {
			oct = oct*8 + (ch-'0');
			ch = GetChar();
		} while (is_oct(ch) && ++cnt < 3);
		UnGetChar();
		ch = oct;
	}
	return ch&0377;
}


int
hex_val(ch)
	register int ch;
{
	return is_dig(ch) ? ch - '0'
			: is_hex(ch) ? (ch - 'a' + 10) & 017
			: -1;
}


int
GetChar()
{
	/*	The routines GetChar and trigraph parses the trigraph
		sequences and removes occurences of \\\n.
	*/
	register int ch;

#ifndef NOPP
again:
#endif
	LoadChar(ch);

#ifndef NOPP
	/* possible trigraph sequence */
	if (ch == '?')
		ch = trigraph();

	/* \<newline> is removed from the input stream */
	if (ch == '\\') {
		LoadChar(ch);
		if (ch == '\n') {
			++LineNumber;
			goto again;
		}
		PushBack();
		ch = '\\';
	}
#endif
	return(LexSave = ch);
}

#ifndef NOPP
int
trigraph()
{
	register int ch;

	LoadChar(ch);
	if (ch == '?') {
		LoadChar(ch);
		switch (ch) {		/* its a trigraph */
		case '=':
			ch =  '#';
			return(ch);
		case '(':
			ch = '[';
			return(ch);
		case '/':
			ch = '\\';
			return(ch);
		case ')':
			ch = ']';
			return(ch);
		case '\'':
			ch = '^';
			return(ch);
		case '<':
			ch = '{';
			return(ch);
		case '!':
			ch = '|';
			return(ch);
		case '>':
			ch = '}';
			return(ch);
		case '-':
			ch = '~';
			return(ch);
		}
		PushBack();
	}
	PushBack();
	return('?');
}
#endif

/* strflt2tok only checks the syntax of the floating-point number and
 * selects the right type for the number.
 */
strflt2tok(fltbuf, ptok)
char fltbuf[];
struct token *ptok;
{
	register char *cp = fltbuf;
	int malformed = 0;

	while (is_dig(*cp)) cp++;
	if (*cp == '.') {
		cp++;
		while (is_dig(*cp)) cp++;
	}
	if (*cp == 'e' || *cp == 'E') {
		cp++;
		if (*cp == '+' || *cp == '-')
			cp++;
		if (!is_dig(*cp)) malformed++;
		while (is_dig(*cp)) cp++;
	}
	if (*cp == 'f' || *cp == 'F') {
		if (*(cp + 1)) malformed++;
		*cp = '\0';
		ptok->tk_fund = FLOAT;
	} else if (*cp == 'l' || *cp == 'L') {
		if (*(cp + 1)) malformed++;
		*cp = '\0';
		ptok->tk_fund = LNGDBL;
	} else {
		if (*cp) malformed++;
		ptok->tk_fund = DOUBLE;
	}
	if (malformed) {
		lexerror("malformed floating constant");
		ptok->tk_fval = Salloc("0.0", (unsigned) 4);
	} else {
		ptok->tk_fval = Salloc(fltbuf, (unsigned) (cp - fltbuf + 1));
	}
}

strint2tok(intbuf, ptok)
char intbuf[];
struct token *ptok;
{
	register char *cp = intbuf;
	int base = 10;
	arith val = 0, dig, ubound;
	int uns_flg = 0, lng_flg = 0, malformed = 0, ovfl = 0;
	int fund;

	assert(*cp != '-');
	if (*cp == '0') {
		cp++;
		if (*cp == 'x' || *cp == 'X') {
			cp++;
			base = 16;
		} else base = 8;
	}
	/* The upperbound will be the same as when computed with
	 * max_unsigned_arith / base (since base is even). The problem here
	 * is that unsigned arith is not accepted by all compilers.
	 */
	ubound = max_arith / (base / 2);

	while (is_hex(*cp)) {
		dig = hex_val(*cp);
		if (dig >= base) {
			malformed++;			/* ignore */
		}
		else {
			if (val < 0 || val > ubound) ovfl++;
			val *= base;
			if (val < 0 && val + dig >= 0) ovfl++;
			val += dig;
		}
		cp++;
	}

	while (*cp) {
		if (*cp == 'l' || *cp == 'L') lng_flg++;
		else if (*cp == 'u' || *cp == 'U') uns_flg++;
		else break;
		cp++;
	}
	if (*cp) {
	    malformed++;
	}
	if (malformed) {
		lexerror("malformed %s integer constant",
				(base == 10 ? "decimal"
					    : (base == 8 ? "octal"
							: "hexadecimal")));
	} else {
		if (lng_flg > 1)
			lexerror("only one long suffix allowed");
		if (uns_flg > 1)
			lexerror("only one unsigned suffix allowed");
	}
	if (ovfl) {
		lexwarning("overflow in constant");
		fund = ULONG;
	} else if (!lng_flg && (val & full_mask[(int)int_size]) == val) {
		if (val >= 0 && val <= max_int) {
			fund = INT;
		} else if (int_size == long_size) {
			fund = UNSIGNED;
		} else if (base == 10 && !uns_flg)
			fund = LONG;
		else	fund = UNSIGNED;
	} else if((val & full_mask[(int)long_size]) == val) {
		if (val >= 0) fund = LONG;
		else fund = ULONG;
	} else {	/* sizeof(arith) is greater than long_size */
		assert(arith_size > long_size);
		lexwarning("constant too large for target machine");
		/* cut the size to prevent further complaints */
		val &= full_mask[(int)long_size];
		fund = ULONG;
	}
	if (lng_flg) {
		/* fund can't be INT */
		if (fund == UNSIGNED) fund = ULONG;
	}
	if (uns_flg) {
	    if (fund == INT) fund = UNSIGNED;
	    else if (fund == LONG) fund = ULONG;
	}
	ptok->tk_fund = fund;
	ptok->tk_ival = val;
}