Re: fixes for type-punning warnings in GCC 4.1

[Alexandre Oliva <aoliva at redhat dot com>]

On Jan 22, 2006, Daniel Jacobowitz <drow@false.org> wrote:

> The output is always a DOUBLEST.  I don't know of any reason why we
> should enable HAVE_LONG_DOUBLE if we can't printf and scanf them; would
> this be simpler in that case?  Don't make DOUBLEST something we can't
> scan or print.

Sounds good to me.  Ok to install?

Index: gdb/c-exp.y
===================================================================
--- gdb/c-exp.y.orig	2006-02-08 00:09:27.000000000 -0200
+++ gdb/c-exp.y	2006-02-08 00:19:55.000000000 -0200
@@ -1080,24 +1080,8 @@ parse_number (p, len, parsed_float, puti
       char saved_char = p[len];
 
       p[len] = 0;	/* null-terminate the token */
-
-      if (sizeof (putithere->typed_val_float.dval) <= sizeof (float))
-	num = sscanf (p, "%g%s", (float *) &putithere->typed_val_float.dval,s);
-      else if (sizeof (putithere->typed_val_float.dval) <= sizeof (double))
-	num = sscanf (p, "%lg%s", (double *) &putithere->typed_val_float.dval,s);
-      else
-	{
-#ifdef SCANF_HAS_LONG_DOUBLE
-	  num = sscanf (p, "%Lg%s", &putithere->typed_val_float.dval,s);
-#else
-	  /* Scan it into a double, then assign it to the long double.
-	     This at least wins with values representable in the range
-	     of doubles. */
-	  double temp;
-	  num = sscanf (p, "%lg%s", &temp,s);
-	  putithere->typed_val_float.dval = temp;
-#endif
-	}
+      num = sscanf (p, DOUBLEST_FORMAT "%s",
+		    &putithere->typed_val_float.dval, s);
       p[len] = saved_char;	/* restore the input stream */
 
       if (num == 1)
Index: gdb/jv-exp.y
===================================================================
--- gdb/jv-exp.y.orig	2006-02-08 00:09:27.000000000 -0200
+++ gdb/jv-exp.y	2006-02-08 00:20:43.000000000 -0200
@@ -713,23 +713,8 @@ parse_number (p, len, parsed_float, puti
       char saved_char = p[len];
 
       p[len] = 0;	/* null-terminate the token */
-      if (sizeof (putithere->typed_val_float.dval) <= sizeof (float))
-	num = sscanf (p, "%g%c", (float *) &putithere->typed_val_float.dval, &c);
-      else if (sizeof (putithere->typed_val_float.dval) <= sizeof (double))
-	num = sscanf (p, "%lg%c", (double *) &putithere->typed_val_float.dval, &c);
-      else
-	{
-#ifdef SCANF_HAS_LONG_DOUBLE
-	  num = sscanf (p, "%Lg%c", &putithere->typed_val_float.dval, &c);
-#else
-	  /* Scan it into a double, then assign it to the long double.
-	     This at least wins with values representable in the range
-	     of doubles. */
-	  double temp;
-	  num = sscanf (p, "%lg%c", &temp, &c);
-	  putithere->typed_val_float.dval = temp;
-#endif
-	}
+      num = sscanf (p, DOUBLEST_FORMAT "%c",
+		    &putithere->typed_val_float.dval, &c);
       p[len] = saved_char;	/* restore the input stream */
       if (num != 1) 		/* check scanf found ONLY a float ... */
 	return ERROR;
Index: gdb/objc-exp.y
===================================================================
--- gdb/objc-exp.y.orig	2006-02-08 00:09:28.000000000 -0200
+++ gdb/objc-exp.y	2006-02-08 00:32:57.000000000 -0200
@@ -1025,23 +1025,8 @@ parse_number (p, len, parsed_float, puti
 
       /* It's a float since it contains a point or an exponent.  */
 
-      if (sizeof (putithere->typed_val_float.dval) <= sizeof (float))
-	sscanf (p, "%g", (float *)&putithere->typed_val_float.dval);
-      else if (sizeof (putithere->typed_val_float.dval) <= sizeof (double))
-	sscanf (p, "%lg", (double *)&putithere->typed_val_float.dval);
-      else
-	{
-#ifdef PRINTF_HAS_LONG_DOUBLE
-	  sscanf (p, "%Lg", &putithere->typed_val_float.dval);
-#else
-	  /* Scan it into a double, then assign it to the long double.
-	     This at least wins with values representable in the range
-	     of doubles.  */
-	  double temp;
-	  sscanf (p, "%lg", &temp);
-	  putithere->typed_val_float.dval = temp;
-#endif
-	}
+      sscanf (p, DOUBLEST_FORMAT "%c",
+	      &putithere->typed_val_float.dval, &c);
 
       /* See if it has `f' or `l' suffix (float or long double).  */
 
Index: gdb/p-exp.y
===================================================================
--- gdb/p-exp.y.orig	2006-02-08 00:09:28.000000000 -0200
+++ gdb/p-exp.y	2006-02-08 00:21:34.000000000 -0200
@@ -799,23 +799,8 @@ parse_number (p, len, parsed_float, puti
       char saved_char = p[len];
 
       p[len] = 0;	/* null-terminate the token */
-      if (sizeof (putithere->typed_val_float.dval) <= sizeof (float))
-	num = sscanf (p, "%g%c", (float *) &putithere->typed_val_float.dval,&c);
-      else if (sizeof (putithere->typed_val_float.dval) <= sizeof (double))
-	num = sscanf (p, "%lg%c", (double *) &putithere->typed_val_float.dval,&c);
-      else
-	{
-#ifdef SCANF_HAS_LONG_DOUBLE
-	  num = sscanf (p, "%Lg%c", &putithere->typed_val_float.dval,&c);
-#else
-	  /* Scan it into a double, then assign it to the long double.
-	     This at least wins with values representable in the range
-	     of doubles. */
-	  double temp;
-	  num = sscanf (p, "%lg%c", &temp,&c);
-	  putithere->typed_val_float.dval = temp;
-#endif
-	}
+      num = sscanf (p, DOUBLEST_FORMAT "%c",
+		    &putithere->typed_val_float.dval, &c);
       p[len] = saved_char;	/* restore the input stream */
       if (num != 1) 		/* check scanf found ONLY a float ... */
 	return ERROR;
Index: gdb/tui/tui-data.c
===================================================================
--- gdb/tui/tui-data.c.orig	2006-02-08 00:09:28.000000000 -0200
+++ gdb/tui/tui-data.c	2006-02-08 00:14:13.000000000 -0200
@@ -44,7 +44,13 @@ static int term_height, term_width;
 static struct tui_gen_win_info _locator;
 static struct tui_gen_win_info exec_info[2];
 static struct tui_win_info * src_win_list[2];
-static struct tui_list source_windows = {(void **) src_win_list, 0};
+/* The intermediate cast to void* silences a type-punning warning
+   issued by GCC.  The use appears to be safe, since we always access
+   source_windows.list with type void**, and whenever we access one of
+   the list members, we cast it to struct tui_win_info*.  The
+   interface of struct tui_list should probably be redesigned with
+   less type opacity to avoid type punning.  -aoliva */
+static struct tui_list source_windows = {(void **) (void *) src_win_list, 0};
 static int default_tab_len = DEFAULT_TAB_LEN;
 static struct tui_win_info * win_with_focus = (struct tui_win_info *) NULL;
 static struct tui_layout_def layout_def =
Index: gdb/varobj.c
===================================================================
--- gdb/varobj.c.orig	2006-02-08 00:09:28.000000000 -0200
+++ gdb/varobj.c	2006-02-08 00:14:13.000000000 -0200
@@ -1374,7 +1374,7 @@ free_variable (struct varobj *var)
   /* Free the expression if this is a root variable. */
   if (var->root->rootvar == var)
     {
-      free_current_contents ((char **) &var->root->exp);
+      free_current_contents (&var->root->exp);
       xfree (var->root);
     }
 
Index: gdb/doublest.h
===================================================================
--- gdb/doublest.h.orig	2006-02-08 00:09:28.000000000 -0200
+++ gdb/doublest.h	2006-02-08 00:25:16.000000000 -0200
@@ -48,10 +48,12 @@ struct floatformat;
    host's `long double'.  In general, we'll probably reduce the precision of
    any such values and print a warning.  */
 
-#ifdef HAVE_LONG_DOUBLE
+#if defined HAVE_LONG_DOUBLE && defined SCANF_HAS_LONG_DOUBLE
 typedef long double DOUBLEST;
+# define DOUBLEST_FORMAT "%Lg"
 #else
 typedef double DOUBLEST;
+# define DOUBLEST_FORMAT "%g"
 #endif
 
 extern void floatformat_to_doublest (const struct floatformat *,

-- 
Alexandre Oliva         http://www.lsd.ic.unicamp.br/~oliva/
Secretary for FSF Latin America        http://www.fsfla.org/
Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}