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[RFC,02/19] Target FP: Simplify floatformat_from_type

Message ID 20170905182040.13FE8D8086F@oc3748833570.ibm.com
State New
Headers show

Commit Message

Ulrich Weigand Sept. 5, 2017, 6:20 p.m. UTC
[RFC][02/19] Target FP: Simplify floatformat_from_type

For historical reasons, the TYPE_FLOATFORMAT element is still set to hold
an array of two floatformat structs, one for big-endian and the other for
little-endian.  When accessing the element via floatformat_from_type,
the code would check the type's byte order and return the appropriate
floatformat.

However, these days this is quite unnecessary, since the type's byte order
is already known at the time the type is allocated and the floatformat is
installed into TYPE_FLOATFORMAT.  Therefore, we can just install the correct
version here.

Also, moved the (now trivially simple) floatformat_from_type accessor to
gdbtypes.{c,h}, since it doesn't really need to be in doublest.c now.

Bye,
Ulrich

ChangeLog:

	* doublest.h (floatformat_from_type): Move to gdbtypes.h.
	* doublest.c (floatformat_from_type): Move to gdbtypes.c.

	* gdbtypes.h (union type_specific): Make field floatformat hold
	just a single struct floatformat, not an array.
	(floatformat_from_type): Move here.
	* gdbtypes.c (floatformat_from_type): Move here.  Update to
	changed TYPE_FLOATFORMAT definition.
	(verify_floatformat): Update to changed TYPE_FLOATFORMAT.
	(recursive_dump_type): Likewise.
	(init_float_type): Install correct floatformat for byte order.
	(arch_float_type): Likewise.

Comments

Simon Marchi Sept. 17, 2017, 3:29 p.m. UTC | #1
On 2017-09-05 20:20, Ulrich Weigand wrote:
> Index: binutils-gdb/gdb/gdbtypes.c
> ===================================================================
> --- binutils-gdb.orig/gdb/gdbtypes.c
> +++ binutils-gdb/gdb/gdbtypes.c
> @@ -2735,22 +2735,31 @@ set_type_code (struct type *type, enum t
>     determined by the floatformat.  Returns size to be used.  */
> 
>  static int
> -verify_floatformat (int bit, const struct floatformat **floatformats)
> +verify_floatformat (int bit, const struct floatformat *floatformat)
>  {
> -  gdb_assert (floatformats != NULL);
> -  gdb_assert (floatformats[0] != NULL && floatformats[1] != NULL);
> +  gdb_assert (floatformat != NULL);
> 
>    if (bit == -1)
> -    bit = floatformats[0]->totalsize;
> +    bit = floatformat->totalsize;
>    gdb_assert (bit >= 0);
> 
>    size_t len = bit / TARGET_CHAR_BIT;
> -  gdb_assert (len >= floatformat_totalsize_bytes (floatformats[0]));
> -  gdb_assert (len >= floatformat_totalsize_bytes (floatformats[1]));
> +  gdb_assert (len * TARGET_CHAR_BIT >= floatformat->totalsize);

That looks funny now.  Is there a reason not to do

   gdb_assert (bit >= floatformat->totalsize);

directly?

Simon
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Patch

Index: binutils-gdb/gdb/doublest.c
===================================================================
--- binutils-gdb.orig/gdb/doublest.c
+++ binutils-gdb/gdb/doublest.c
@@ -770,22 +770,6 @@  floatformat_from_doublest (const struct
 }
 
 
-/* Return the floating-point format for a floating-point variable of
-   type TYPE.  */
-
-const struct floatformat *
-floatformat_from_type (const struct type *type)
-{
-  struct gdbarch *gdbarch = get_type_arch (type);
-  const struct floatformat *fmt;
-
-  gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
-  gdb_assert (TYPE_FLOATFORMAT (type));
-  fmt = TYPE_FLOATFORMAT (type)[gdbarch_byte_order (gdbarch)];
-  gdb_assert (TYPE_LENGTH (type) >= floatformat_totalsize_bytes (fmt));
-  return fmt;
-}
-
 /* Extract a floating-point number of type TYPE from a target-order
    byte-stream at ADDR.  Returns the value as type DOUBLEST.  */
 
Index: binutils-gdb/gdb/doublest.h
===================================================================
--- binutils-gdb.orig/gdb/doublest.h
+++ binutils-gdb/gdb/doublest.h
@@ -71,12 +71,6 @@  extern enum float_kind floatformat_class
 extern const char *floatformat_mantissa (const struct floatformat *,
 					 const bfd_byte *);
 
-/* Given TYPE, return its floatformat.  TYPE_FLOATFORMAT() may return
-   NULL.  type_floatformat() detects that and returns a floatformat
-   based on the type size when FLOATFORMAT is NULL.  */
-
-const struct floatformat *floatformat_from_type (const struct type *type);
-
 /* Return the floatformat's total size in host bytes.  */
 
 extern size_t floatformat_totalsize_bytes (const struct floatformat *fmt);
Index: binutils-gdb/gdb/gdbtypes.c
===================================================================
--- binutils-gdb.orig/gdb/gdbtypes.c
+++ binutils-gdb/gdb/gdbtypes.c
@@ -2735,22 +2735,31 @@  set_type_code (struct type *type, enum t
    determined by the floatformat.  Returns size to be used.  */
 
 static int
-verify_floatformat (int bit, const struct floatformat **floatformats)
+verify_floatformat (int bit, const struct floatformat *floatformat)
 {
-  gdb_assert (floatformats != NULL);
-  gdb_assert (floatformats[0] != NULL && floatformats[1] != NULL);
+  gdb_assert (floatformat != NULL);
 
   if (bit == -1)
-    bit = floatformats[0]->totalsize;
+    bit = floatformat->totalsize;
   gdb_assert (bit >= 0);
 
   size_t len = bit / TARGET_CHAR_BIT;
-  gdb_assert (len >= floatformat_totalsize_bytes (floatformats[0]));
-  gdb_assert (len >= floatformat_totalsize_bytes (floatformats[1]));
+  gdb_assert (len * TARGET_CHAR_BIT >= floatformat->totalsize);
 
   return bit;
 }
 
+/* Return the floating-point format for a floating-point variable of
+   type TYPE.  */
+
+const struct floatformat *
+floatformat_from_type (const struct type *type)
+{
+  gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT);
+  gdb_assert (TYPE_FLOATFORMAT (type));
+  return TYPE_FLOATFORMAT (type);
+}
+
 /* Helper function to initialize the standard scalar types.
 
    If NAME is non-NULL, then it is used to initialize the type name.
@@ -2842,11 +2851,13 @@  init_float_type (struct objfile *objfile
 		 int bit, const char *name,
 		 const struct floatformat **floatformats)
 {
+  struct gdbarch *gdbarch = get_objfile_arch (objfile);
+  const struct floatformat *fmt = floatformats[gdbarch_byte_order (gdbarch)];
   struct type *t;
 
-  bit = verify_floatformat (bit, floatformats);
+  bit = verify_floatformat (bit, fmt);
   t = init_type (objfile, TYPE_CODE_FLT, bit / TARGET_CHAR_BIT, name);
-  TYPE_FLOATFORMAT (t) = floatformats;
+  TYPE_FLOATFORMAT (t) = fmt;
 
   return t;
 }
@@ -4544,26 +4555,11 @@  recursive_dump_type (struct type *type,
 
       case TYPE_SPECIFIC_FLOATFORMAT:
 	printfi_filtered (spaces, "floatformat ");
-	if (TYPE_FLOATFORMAT (type) == NULL)
+	if (TYPE_FLOATFORMAT (type) == NULL
+	    || TYPE_FLOATFORMAT (type)->name == NULL)
 	  puts_filtered ("(null)");
 	else
-	  {
-	    puts_filtered ("{ ");
-	    if (TYPE_FLOATFORMAT (type)[0] == NULL
-		|| TYPE_FLOATFORMAT (type)[0]->name == NULL)
-	      puts_filtered ("(null)");
-	    else
-	      puts_filtered (TYPE_FLOATFORMAT (type)[0]->name);
-
-	    puts_filtered (", ");
-	    if (TYPE_FLOATFORMAT (type)[1] == NULL
-		|| TYPE_FLOATFORMAT (type)[1]->name == NULL)
-	      puts_filtered ("(null)");
-	    else
-	      puts_filtered (TYPE_FLOATFORMAT (type)[1]->name);
-
-	    puts_filtered (" }");
-	  }
+	  puts_filtered (TYPE_FLOATFORMAT (type)->name);
 	puts_filtered ("\n");
 	break;
 
@@ -4907,11 +4903,12 @@  arch_float_type (struct gdbarch *gdbarch
 		 int bit, const char *name,
 		 const struct floatformat **floatformats)
 {
+  const struct floatformat *fmt = floatformats[gdbarch_byte_order (gdbarch)];
   struct type *t;
 
-  bit = verify_floatformat (bit, floatformats);
+  bit = verify_floatformat (bit, fmt);
   t = arch_type (gdbarch, TYPE_CODE_FLT, bit / TARGET_CHAR_BIT, name);
-  TYPE_FLOATFORMAT (t) = floatformats;
+  TYPE_FLOATFORMAT (t) = fmt;
 
   return t;
 }
Index: binutils-gdb/gdb/gdbtypes.h
===================================================================
--- binutils-gdb.orig/gdb/gdbtypes.h
+++ binutils-gdb/gdb/gdbtypes.h
@@ -571,12 +571,11 @@  union type_specific
 
   struct gnat_aux_type *gnat_stuff;
 
-  /* * FLOATFORMAT is for TYPE_CODE_FLT.  It is a pointer to two
-     floatformat objects that describe the floating-point value
-     that resides within the type.  The first is for big endian
-     targets and the second is for little endian targets.  */
+  /* * FLOATFORMAT is for TYPE_CODE_FLT.  It is a pointer to a
+     floatformat object that describes the floating-point value
+     that resides within the type.  */
 
-  const struct floatformat **floatformat;
+  const struct floatformat *floatformat;
 
   /* * For TYPE_CODE_FUNC and TYPE_CODE_METHOD types.  */
 
@@ -1434,6 +1433,9 @@  extern void set_type_vptr_basetype (stru
 #define TYPE_ERROR_NAME(type) \
   (TYPE_NAME (type) ? TYPE_NAME (type) : _("<error type>"))
 
+/* Given TYPE, return its floatformat.  */
+const struct floatformat *floatformat_from_type (const struct type *type);
+
 struct builtin_type
 {
   /* Integral types.  */