668 lines
15 KiB
C
668 lines
15 KiB
C
/* $Header$ */
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/* PREPROCESSOR: CONTROLLINE INTERPRETER */
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#include "interface.h"
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#include "arith.h"
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#include "LLlex.h"
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#include "Lpars.h"
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#include "debug.h"
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#include "idf.h"
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#include "input.h"
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#include "nopp.h"
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#ifndef NOPP
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#include "ifdepth.h"
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#include "botch_free.h"
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#include "nparams.h"
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#include "parbufsize.h"
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#include "textsize.h"
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#include "idfsize.h"
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#include "assert.h"
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#include "alloc.h"
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#include "class.h"
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#include "macro.h"
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#include "storage.h"
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IMPORT char *inctable[]; /* list of include directories */
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PRIVATE char ifstack[IFDEPTH]; /* if-stack: the content of an entry is */
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/* 1 if a corresponding ELSE has been */
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/* encountered. */
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PRIVATE int nestlevel = -1; /* initially no nesting level. */
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PRIVATE struct idf *
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GetIdentifier()
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{
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/* returns a pointer to the descriptor of the identifier that is
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read from the input stream. A null-pointer is returned if
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the input does not contain an identifier.
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The substitution of macros is disabled.
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*/
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int tok;
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struct token tk;
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ReplaceMacros = 0;
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tok = GetToken(&tk);
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ReplaceMacros = 1;
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return tok == IDENTIFIER ? tk.tk_idf : (struct idf *)0;
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}
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/* domacro() is the control line interpreter. The '#' has already
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been read by the lexical analyzer by which domacro() is called.
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The token appearing directly after the '#' is obtained by calling
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the basic lexical analyzing function GetToken() and is interpreted
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to perform the action belonging to that token.
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An error message is produced when the token is not recognized,
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i.e. it is not one of "define" .. "undef" , integer or newline.
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*/
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EXPORT
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domacro()
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{
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struct token tk; /* the token itself */
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EoiForNewline = 1;
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SkipEscNewline = 1;
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switch(GetToken(&tk)) { /* select control line action */
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case IDENTIFIER: /* is it a macro keyword? */
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switch (tk.tk_idf->id_resmac) {
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case K_DEFINE: /* "define" */
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do_define();
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break;
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case K_ELIF: /* "elif" */
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do_elif();
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break;
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case K_ELSE: /* "else" */
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do_else();
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break;
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case K_ENDIF: /* "endif" */
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do_endif();
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break;
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case K_IF: /* "if" */
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do_if();
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break;
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case K_IFDEF: /* "ifdef" */
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do_ifdef(1);
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break;
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case K_IFNDEF: /* "ifndef" */
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do_ifdef(0);
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break;
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case K_INCLUDE: /* "include" */
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do_include();
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break;
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case K_LINE: /* "line" */
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/* set LineNumber and FileName according to
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the arguments.
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*/
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if (GetToken(&tk) != INTEGER) {
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lexerror("#line without linenumber");
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SkipRestOfLine();
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}
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else
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do_line((unsigned int)tk.tk_ival);
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break;
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case K_UNDEF: /* "undef" */
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do_undef();
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break;
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default:
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/* invalid word seen after the '#' */
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lexerror("%s: unknown control", tk.tk_idf->id_text);
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SkipRestOfLine();
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}
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break;
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case INTEGER: /* # <integer> [<filespecifier>]? */
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do_line((unsigned int)tk.tk_ival);
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break;
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case EOI: /* only `#' on this line: do nothing, ignore */
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break;
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default: /* invalid token following '#' */
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lexerror("illegal # line");
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SkipRestOfLine();
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}
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EoiForNewline = 0;
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SkipEscNewline = 0;
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}
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PRIVATE
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skip_block()
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{
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/* skip_block() skips the input from
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1) a false #if, #ifdef, #ifndef or #elif until the
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corresponding #elif (resulting in true), #else or
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#endif is read.
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2) a #else corresponding to a true #if, #ifdef,
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#ifndef or #elif until the corresponding #endif is
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seen.
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*/
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register int ch;
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register skiplevel = nestlevel; /* current nesting level */
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struct token tk;
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NoUnstack++;
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for (;;) {
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LoadChar(ch); /* read first character after newline */
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if (ch != '#') {
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if (ch == EOI) {
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NoUnstack--;
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return;
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}
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SkipRestOfLine();
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continue;
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}
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if (GetToken(&tk) != IDENTIFIER) {
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SkipRestOfLine();
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continue;
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}
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/* an IDENTIFIER: look for #if, #ifdef and #ifndef
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without interpreting them.
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Interpret #else, #elif and #endif if they occur
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on the same level.
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*/
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switch(tk.tk_idf->id_resmac) {
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case K_IF:
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case K_IFDEF:
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case K_IFNDEF:
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push_if();
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break;
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case K_ELIF:
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if (nestlevel == skiplevel) {
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nestlevel--;
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push_if();
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if (ifexpr()) {
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NoUnstack--;
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return;
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}
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}
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break;
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case K_ELSE:
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++(ifstack[nestlevel]);
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if (nestlevel == skiplevel) {
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SkipRestOfLine();
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NoUnstack--;
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return;
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}
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break;
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case K_ENDIF:
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ASSERT(nestlevel >= 0);
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if (nestlevel == skiplevel) {
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SkipRestOfLine();
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nestlevel--;
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NoUnstack--;
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return;
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}
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nestlevel--;
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break;
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}
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}
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}
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PRIVATE
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ifexpr()
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{
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/* ifexpr() returns whether the restricted constant
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expression following #if or #elif evaluates to true. This
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is done by calling the LLgen generated subparser for
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constant expressions. The result of this expression will
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be given in the extern long variable "ifval".
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*/
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IMPORT arith ifval;
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int errors = err_occurred;
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ifval = (arith)0;
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AccDefined = 1;
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UnknownIdIsZero = 1;
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PushLex(); /* NEW parser */
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If_expr(); /* invoke constant expression parser */
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PopLex(); /* OLD parser */
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AccDefined = 0;
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UnknownIdIsZero = 0;
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return (errors == err_occurred) && (ifval != (arith)0);
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}
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PRIVATE
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do_include()
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{
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/* do_include() performs the inclusion of a file.
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*/
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char *filenm;
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int tok;
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struct token tk;
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AccFileSpecifier = 1;
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if (((tok = GetToken(&tk)) == FILESPECIFIER) || tok == STRING)
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filenm = tk.tk_bts;
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else {
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lexerror("bad include syntax");
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filenm = (char *)0;
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}
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AccFileSpecifier = 0;
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SkipRestOfLine();
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if (filenm && !InsertFile(filenm, &inctable[tok == FILESPECIFIER]))
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lexerror("cannot find include file \"%s\"", filenm);
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}
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PRIVATE
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do_define()
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{
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/* do_define() interprets a #define control line.
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*/
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struct idf *id; /* the #defined identifier's descriptor */
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int nformals = -1; /* keep track of the number of formals */
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char *formals[NPARAMS]; /* pointers to the names of the formals */
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char parbuf[PARBUFSIZE]; /* names of formals */
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char *repl_text; /* start of the replacement text */
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int length; /* length of the replacement text */
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register ch;
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char *get_text();
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/* read the #defined macro's name */
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if (!(id = GetIdentifier())) {
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lexerror("#define: illegal macro name");
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SkipRestOfLine();
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return;
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}
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/* there is a formal parameter list if the identifier is
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followed immediately by a '('.
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*/
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LoadChar(ch);
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if (ch == '(') {
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if ((nformals = getparams(formals, parbuf)) == -1) {
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SkipRestOfLine();
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return; /* an error occurred */
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}
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LoadChar(ch);
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}
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/* read the replacement text if there is any */
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ch = skipspaces(ch); /* find first character of the text */
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ASSERT(ch != EOI);
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if (class(ch) == STNL) {
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/* Treat `#define something' as `#define something ""'
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*/
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repl_text = "";
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length = 0;
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}
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else {
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PushBack();
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repl_text = get_text((nformals > 0) ? formals : 0, &length);
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}
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macro_def(id, repl_text, nformals, length, NOFLAG);
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LineNumber++;
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}
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PRIVATE
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push_if()
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{
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if (nestlevel >= IFDEPTH)
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fatal("too many nested #if/#ifdef/#ifndef");
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else
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ifstack[++nestlevel] = 0;
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}
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PRIVATE
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do_elif()
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{
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if (nestlevel < 0 || (ifstack[nestlevel])) {
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lexerror("#elif without corresponding #if");
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SkipRestOfLine();
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}
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else { /* restart at this level as if a #if is detected. */
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nestlevel--;
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push_if();
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skip_block();
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}
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}
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PRIVATE
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do_else()
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{
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SkipRestOfLine();
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if (nestlevel < 0 || (ifstack[nestlevel]))
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lexerror("#else without corresponding #if");
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else { /* mark this level as else-d */
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++(ifstack[nestlevel]);
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skip_block();
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}
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}
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PRIVATE
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do_endif()
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{
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SkipRestOfLine();
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if (nestlevel-- < 0)
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lexerror("#endif without corresponding #if");
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}
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PRIVATE
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do_if()
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{
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push_if();
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if (!ifexpr()) /* a false #if/#elif expression */
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skip_block();
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}
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PRIVATE
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do_ifdef(how)
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{
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struct idf *id;
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/* how == 1 : ifdef; how == 0 : ifndef
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*/
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push_if();
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if (id = GetIdentifier()) {
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if (
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(how && !(id && id->id_macro))
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||
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(!how && id && id->id_macro)
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) /* this id is not defined */
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skip_block();
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else
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SkipRestOfLine();
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}
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else {
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lexerror("illegal #ifdef construction");
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SkipRestOfLine();
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}
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}
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PRIVATE
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do_undef()
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{
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struct idf *id;
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/* Forget a macro definition. */
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if (id = GetIdentifier()) {
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if (id && id->id_macro) { /* forget the macro */
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free_macro(id->id_macro);
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id->id_macro = (struct macro *) 0;
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} /* else: don't complain */
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}
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else
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lexerror("illegal #undef construction");
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SkipRestOfLine();
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}
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PRIVATE
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do_line(l)
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unsigned int l;
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{
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struct token tk;
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LineNumber = l - 1; /* the number of the next input line */
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if (GetToken(&tk) == STRING) /* is there a filespecifier? */
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FileName = tk.tk_bts;
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SkipRestOfLine();
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}
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PRIVATE int
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getparams(buf, parbuf)
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char *buf[];
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char parbuf[];
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{
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/* getparams() reads the formal parameter list of a macro
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definition.
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The number of parameters is returned.
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As a formal parameter list is expected when calling this
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routine, -1 is returned if an error is detected, for
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example:
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#define one(1), where 1 is not an identifier.
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Note that the '(' has already been eaten.
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The names of the formal parameters are stored into parbuf.
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*/
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register count = 0;
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register c;
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register char *ptr = &parbuf[0];
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LoadChar(c);
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c = skipspaces(c);
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if (c == ')') { /* no parameters: #define name() */
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buf[0] = (char *) 0;
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return 0;
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}
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for (;;) { /* eat the formal parameter list */
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if (class(c) != STIDF) { /* not an identifier */
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lexerror("#define: bad formal parameter");
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return -1;
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}
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buf[count++] = ptr; /* name of the formal */
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*ptr++ = c;
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if (ptr >= &parbuf[PARBUFSIZE])
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fatal("formal parameter buffer overflow");
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do { /* eat the identifier name */
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LoadChar(c);
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*ptr++ = c;
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if (ptr >= &parbuf[PARBUFSIZE])
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fatal("formal parameter buffer overflow");
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} while (in_idf(c));
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*(ptr - 1) = '\0'; /* mark end of the name */
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c = skipspaces(c);
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if (c == ')') { /* end of the formal parameter list */
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buf[count] = (char *) 0;
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return count;
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}
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if (c != ',') {
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lexerror("#define: bad formal parameter list");
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return -1;
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}
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LoadChar(c);
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c = skipspaces(c);
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}
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}
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EXPORT
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macro_def(id, text, nformals, length, flags)
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struct idf *id;
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char *text;
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{
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register struct macro *newdef = id->id_macro;
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/* macro_def() puts the contents and information of a macro
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definition into a structure and stores it into the symbol
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table entry belonging to the name of the macro.
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A warning is given if the definition overwrites another
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(unless predefined!)
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*/
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if (newdef) { /* is there a redefinition? */
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if ((newdef->mc_flag & PREDEF) == 0) {
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if (macroeq(newdef->mc_text, text))
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return;
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lexwarning("redefine \"%s\"", id->id_text);
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} /* else: overwrite pre-definition */
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}
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else
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id->id_macro = newdef = new_macro();
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newdef->mc_text = text; /* replacement text */
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newdef->mc_nps = nformals; /* nr of formals */
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newdef->mc_length = length; /* length of repl. text */
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newdef->mc_flag = flags; /* special flags */
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}
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PRIVATE int
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find_name(nm, index)
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char *nm, *index[];
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{
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/* find_name() returns the index of "nm" in the namelist
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"index" if it can be found there. 0 is returned if it is
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not there.
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*/
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register char **ip = &index[0];
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while (*ip)
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if (strcmp(nm, *ip++) == 0)
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return ip - &index[0];
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/* arrived here, nm is not in the name list. */
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return 0;
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}
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PRIVATE char *
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get_text(formals, length)
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char *formals[];
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int *length;
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{
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/* get_text() copies the replacement text of a macro
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definition with zero, one or more parameters, thereby
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substituting each formal parameter by a special character
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(non-ascii: 0200 & (order-number in the formal parameter
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list)) in order to substitute this character later by the
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actual parameter. The replacement text is copied into
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itself because the copied text will contain fewer or the
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same amount of characters. The length of the replacement
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text is returned.
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Implementation:
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finite automaton : we are only interested in
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identifiers, because they might be replaced by some actual
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parameter. Other tokens will not be seen as such.
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*/
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register c;
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register text_size;
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char *text = Malloc(text_size = ITEXTSIZE);
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register pos = 0;
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LoadChar(c);
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while ((c != EOI) && (class(c) != STNL)) {
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if (c == '\\') { /* check for "\\\n" */
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LoadChar(c);
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if (c == '\n') {
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/* More than one line is used for the
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replacement text.
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Replace "\\\n" by " ".
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*/
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text[pos++] = ' ';
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++LineNumber;
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LoadChar(c);
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}
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else
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text[pos++] = '\\';
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if (pos == text_size)
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text = Srealloc(text, text_size += RTEXTSIZE);
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}
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else
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if ( c == '/') {
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LoadChar(c);
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if (c == '*') {
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skipcomment();
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text[pos++] = ' ';
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LoadChar(c);
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}
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else
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text[pos++] = '/';
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if (pos == text_size)
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text = Srealloc(text, text_size += RTEXTSIZE);
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}
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else
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if (formals && class(c) == STIDF) {
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char id_buf[IDFSIZE + 1];
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register id_size = 0;
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register n;
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/* read identifier: it may be a formal parameter */
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id_buf[id_size++] = c;
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do {
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LoadChar(c);
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if (id_size <= IDFSIZE)
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id_buf[id_size++] = c;
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} while (in_idf(c));
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id_buf[--id_size] = '\0';
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if (n = find_name(id_buf, formals)) {
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/* construct the formal parameter mark */
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text[pos++] = FORMALP | (char) n;
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if (pos == text_size)
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text = Srealloc(text,
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text_size += RTEXTSIZE);
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}
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else {
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register char *ptr = &id_buf[0];
|
|
|
|
while (pos + id_size >= text_size)
|
|
text = Srealloc(text,
|
|
text_size += RTEXTSIZE);
|
|
while (text[pos++] = *ptr++) ;
|
|
pos--;
|
|
}
|
|
}
|
|
else {
|
|
text[pos++] = c;
|
|
if (pos == text_size)
|
|
text = Srealloc(text, text_size += RTEXTSIZE);
|
|
LoadChar(c);
|
|
}
|
|
}
|
|
text[pos++] = '\0';
|
|
*length = pos - 1;
|
|
return text;
|
|
}
|
|
|
|
#define BLANK(ch) ((ch == ' ') || (ch == '\t'))
|
|
|
|
/* macroeq() decides whether two macro replacement texts are
|
|
identical. This version compares the texts, which occur
|
|
as strings, without taking care of the leading and trailing
|
|
blanks (spaces and tabs).
|
|
*/
|
|
PRIVATE
|
|
macroeq(s, t)
|
|
register char *s, *t;
|
|
{
|
|
|
|
/* skip leading spaces */
|
|
while (BLANK(*s)) s++;
|
|
while (BLANK(*t)) t++;
|
|
/* first non-blank encountered in both strings */
|
|
/* The actual comparison loop: */
|
|
while (*s && *s == *t)
|
|
s++, t++;
|
|
/* two cases are possible when arrived here: */
|
|
if (*s == '\0') { /* *s == '\0' */
|
|
while (BLANK(*t)) t++;
|
|
return *t == '\0';
|
|
}
|
|
else { /* *s != *t */
|
|
while (BLANK(*s)) s++;
|
|
while (BLANK(*t)) t++;
|
|
return (*s == '\0') && (*t == '\0');
|
|
}
|
|
}
|
|
#else NOPP
|
|
EXPORT
|
|
domacro()
|
|
{
|
|
int tok;
|
|
struct token tk;
|
|
|
|
EoiForNewline = 1;
|
|
SkipEscNewline = 1;
|
|
if ((tok = GetToken(&tk)) == IDENTIFIER) {
|
|
if (strcmp(tk.tk_idf->id_text, "line") != 0) {
|
|
error("illegal # line");
|
|
SkipRestOfLine();
|
|
return;
|
|
}
|
|
tok = GetToken(&tk);
|
|
}
|
|
if (tok != INTEGER) {
|
|
error("illegal # line");
|
|
SkipRestOfLine();
|
|
return;
|
|
}
|
|
LineNumber = tk.tk_ival - 1; /* number of the next line */
|
|
if ((tok = GetToken(&tk)) == STRING)
|
|
FileName = tk.tk_bts;
|
|
else
|
|
if (tok != EOI) {
|
|
error("illegal # line");
|
|
SkipRestOfLine();
|
|
}
|
|
EoiForNewline = 0;
|
|
SkipEscNewline = 0;
|
|
}
|
|
#endif NOPP
|
|
|
|
PRIVATE
|
|
SkipRestOfLine()
|
|
{
|
|
/* we do a PushBack because we don't want to skip the next line
|
|
if the last character was a newline
|
|
*/
|
|
PushBack();
|
|
skipline();
|
|
}
|