Add %warning, saner unquoting of %error

- Add %warning directive
- Only unquote an %error or %warning string if it is the only thing on
  the directive line.
- Don't expand macros inside a quoted string, even for %error.

doc/nasmdoc.src

@@ -2874,19 +2874,19 @@ any tokens at all, whitespace excepted.
 The usual \i\c{%elifempty}, \i\c\{%ifnempty}, and \i\c{%elifnempty}
 variants are also provided.
 
-\S{pperror} \i\c{%error}: Reporting \i{User-Defined Errors}
+\S{pperror} \i\c{%error} and \i\c{%warning}: Reporting \i{User-Defined Errors}
 
 The preprocessor directive \c{%error} will cause NASM to report an
 error if it occurs in assembled code. So if other users are going to
-try to assemble your source files, you can ensure that they define
-the right macros by means of code like this:
+try to assemble your source files, you can ensure that they define the
+right macros by means of code like this:
 
-\c %ifdef SOME_MACRO
+\c %ifdef F1
 \c     ; do some setup
-\c %elifdef SOME_OTHER_MACRO
+\c %elifdef F2
 \c     ; do some different setup
 \c %else
-\c     %error Neither SOME_MACRO nor SOME_OTHER_MACRO was defined.
+\c     %error Neither F1 nor F2 was defined.
 \c %endif
 
 Then any user who fails to understand the way your code is supposed
@@ -2894,6 +2894,16 @@ to be assembled will be quickly warned of their mistake, rather than
 having to wait until the program crashes on being run and then not
 knowing what went wrong.
 
+Similarly, \c{%warning} issues a warning:
+
+\c %ifdef F1
+\c     ; do some setup
+\c %elifdef F2
+\c     ; do some different setup
+\c %else
+\c     %warning Neither F1 nor F2 was defined, assuming F1.
+\c     %define F1
+\c %endif
 
 \H{rep} \i{Preprocessor Loops}\I{repeating code}: \i\c{%rep}
 

nasm.c

@@ -1909,7 +1909,7 @@ static bool is_suppressed_warning(int severity)
 static void report_error_common(int severity, const char *fmt,
                                 va_list args)
 {
-    switch (severity & ERR_MASK) {
+    switch (severity & (ERR_MASK|ERR_NO_SEVERITY)) {
     case ERR_WARNING:
         fputs("warning: ", error_file);
         break;
@@ -1925,6 +1925,8 @@ static void report_error_common(int severity, const char *fmt,
     case ERR_DEBUG:
         fputs("debug: ", error_file);
         break;
+    default:
+	break;
     }
 
     vfprintf(error_file, fmt, args);

nasmlib.h

@@ -54,6 +54,7 @@ extern efunc nasm_malloc_error;
 #define ERR_NOFILE	0x00000010      /* don't give source file name/line */
 #define ERR_USAGE	0x00000020      /* print a usage message */
 #define ERR_PASS1	0x00000040      /* only print this error on pass one */
+#define ERR_NO_SEVERITY 0x00000080	/* suppress printing severity */
 
 /*
  * These codes define specific types of suppressible warning.

pptok.dat

@@ -47,4 +47,5 @@
 %strlen
 %substr
 %undef
+%warning
 %xdefine

preproc.c

@@ -2192,22 +2192,30 @@ static int do_directive(Token * tline)
         break;
 
     case PP_ERROR:
+    case PP_WARNING:
+    {
+	int severity = PP_ERROR ? ERR_NONFATAL|ERR_NO_SEVERITY :
+	    ERR_WARNING|ERR_NO_SEVERITY;
+
         tline->next = expand_smacro(tline->next);
         tline = tline->next;
         skip_white_(tline);
-        if (tok_type_(tline, TOK_STRING)) {
+	t = tline ? tline->next : NULL;
+	skip_white_(t);
+        if (tok_type_(tline, TOK_STRING) && !t) {
+	    /* The line contains only a quoted string */
 	    p = tline->text;
 	    nasm_unquote(p, NULL);
-	    expand_macros_in_string(&p); /* WHY? */
-            error(ERR_NONFATAL, "%s", p);
-            nasm_free(p);
-        } else {
+	    error(severity, "%s: %s",  pp_directives[i], p);
+	} else {
+	    /* Not a quoted string, or more than a quoted string */
             p = detoken(tline, false);
-            error(ERR_WARNING, "%s", p); /* WARNING!??!! */
-            nasm_free(p);
-        }
+	    error(severity, "%s: %s",  pp_directives[i], p);
+	    nasm_free(p);
+	}	    
         free_tlist(origline);
         break;
+    }
 
     CASE_PP_IF:
         if (istk->conds && !emitting(istk->conds->state))