rules.c

这是MAKE命令的原代码。是一个很好的编译程序的例子。不好懂。不过是很好的学习资料。希望对需要的朋友有点收获。

/*
 *	Control of the implicit suffix rules
 */


#include "h.h"


/*
 *	Return a pointer to the suffix of a name
 */
char *suffix(char *name)
{
  return strrchr(name, '.');
}


/*
 *	Dynamic dependency.  This routine applies the suffis rules
 *	to try and find a source and a set of rules for a missing
 *	target.  If found, np is made into a target with the implicit
 *	source name, and rules.  Returns TRUE if np was made into
 *	a target.
 */
bool
dyndep(np)
struct name *		np;
{
  register char *		p;
  register char *		q;
  register char *		suff;		/*  Old suffix  */
  register char *		basename;	/*  Name without suffix  */
  struct name *		op;		/*  New dependent  */
  struct name *		sp;		/*  Suffix  */
  struct line *		lp;
  struct depend *		dp;
  char *			newsuff;
  
  
  p = str1;
  q = np->n_name;
  if (!(suff = suffix(q)))
    return FALSE;		/* No suffix */
  while (q < suff)
    *p++ = *q++;
  *p = '\0';
  basename = setmacro("*", str1)->m_val;
  
  if (!((sp = newname(".SUFFIXES"))->n_flag & N_TARG))
    return FALSE;
  
  for (lp = sp->n_line; lp; lp = lp->l_next)
    for (dp = lp->l_dep; dp; dp = dp->d_next)
      {
	newsuff = dp->d_name->n_name;
	if (strlen(suff)+strlen(newsuff)+1 >= LZ)
	  fatal("Suffix rule too long");
	p = str1;
	q = newsuff;
	while (*p++ = *q++)
	  ;
	p--;
	q = suff;
	while (*p++ = *q++)
	  ;
	sp = newname(str1);
	if (sp->n_flag & N_TARG)
	  {
	    p = str1;
	    q = basename;
	    if (strlen(basename) + strlen(newsuff)+1 >= LZ)
	      fatal("Implicit name too long");
	    while (*p++ = *q++)
	      ;
	    p--;
	    q = newsuff;
	    while (*p++ = *q++)
	      ;
	    op = newname(str1);
	    if (!op->n_time)
	      modtime(op);
	    if (op->n_time)
	      {
		dp = newdep(op, 0);
		newline(np, dp, sp->n_line->l_cmd, 0);
		setmacro("<", op->n_name);
		return TRUE;
	      }
	  }
      }
  return FALSE;
}


/*
 *	Make the default rules
 */
void
makerules()
{
  struct cmd *cp;
  struct name *np;
  struct depend *dp;
  
  setmacro("CC", "lcc");
  setmacro("CFLAGS", "-O");
  np = newname(".c.obj");
  cp = newcmd("$(CC) $(CFLAGS) $<", 0);
  newline(np, 0, cp, 0);
  
  setmacro("AS", "lcc");
  np = newname(".asm.obj");
  cp = newcmd("$(AS) $<", 0);
  newline(np, 0, cp, 0);

  np = newname(".obj");
  dp = newdep(np, 0);

  np = newname(".asm");
  dp = newdep(np, dp);

  np = newname(".c");
  dp = newdep(np, dp);

  np = newname(".SUFFIXES");
  newline(np, dp, 0, 0);

  setmacro ("MAKE",myname);
}