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Commit 95f79357 by Zack Weinberg
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c-decl.c (start_decl): Unconditionally issue error for 'typedef foo = bar'. 

gcc:
	* c-decl.c (start_decl): Unconditionally issue error for
	'typedef foo = bar'.
	(finish_decl): Remove special case for TYPE_DECL with initializer.

	* doc/extend.texi: Delete "Naming Types" section.  Change all
	cross-references to that section to refer to "Typeof" instead.
	Add the useful safe-max()-macro example from "Naming Types" to
	"Typeof", rewritten using that extension.

gcc/cp:
	* decl.c (start_decl): Unconditionally issue error for
	'typedef foo = bar'.
	(cp_finish_decl): Remove special case for TYPE_DECL with initializer.
	(grokdeclarator): Remove redundant error for 'typedef foo = bar'.

gcc/testsuite:
	* g++.dg/ext/typedef-init.C: New test.
	* gcc.dg/typedef-init.c: New test.

From-SVN: r57995
parent 10a38dba
Showing with 101 additions and 73 deletions
gcc/ChangeLog
2002-10-09 Zack Weinberg <zack@codesourcery.com>
PR c/7353
* c-decl.c (start_decl): Unconditionally issue error for
'typedef foo = bar'.
(finish_decl): Remove special case for TYPE_DECL with initializer.
* doc/extend.texi: Delete "Naming Types" section. Change all
cross-references to that section to refer to "Typeof" instead.
Add the useful safe-max()-macro example from "Naming Types" to
"Typeof", rewritten using that extension. Add some compatibility
notes to "Typeof."
2002-10-09 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* loop.c: Revert 2002-08-15 change.
......
gcc/c-decl.c
......@@ -2821,15 +2821,9 @@ start_decl (declarator, declspecs, initialized, attributes)
switch (TREE_CODE (decl))
{
case TYPE_DECL:
/* typedef foo = bar means give foo the same type as bar.
We haven't parsed bar yet, so `finish_decl' will fix that up.
Any other case of an initialization in a TYPE_DECL is an error. */
if (pedantic || list_length (declspecs) > 1)
{
error ("typedef `%s' is initialized",
IDENTIFIER_POINTER (DECL_NAME (decl)));
initialized = 0;
}
error ("typedef `%s' is initialized",
IDENTIFIER_POINTER (DECL_NAME (decl)));
initialized = 0;
break;
case FUNCTION_DECL:
......@@ -2988,16 +2982,7 @@ finish_decl (decl, init, asmspec_tree)
init = 0;
if (init)
{
if (TREE_CODE (decl) != TYPE_DECL)
store_init_value (decl, init);
else
{
/* typedef foo = bar; store the type of bar as the type of foo. */
TREE_TYPE (decl) = TREE_TYPE (init);
DECL_INITIAL (decl) = init = 0;
}
}
store_init_value (decl, init);
/* Deduce size of array from initialization, if not already known */
if (TREE_CODE (type) == ARRAY_TYPE
......
gcc/cp/ChangeLog
2002-10-09 Zack Weinberg <zack@codesourcery.com>
* decl.c (start_decl): Unconditionally issue error for
'typedef foo = bar'.
(cp_finish_decl): Remove special case for TYPE_DECL with initializer.
(grokdeclarator): Remove redundant error for 'typedef foo = bar'.
2002-10-09 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* decl2.c (prune_vtable_vardecl): Delete unused function.
......@@ -84,7 +91,7 @@
2002-10-02 Matt Austern <austern@apple.com>
* decl.c (walk_vtables_r): Fixed typo that caused result to
never get a nonzero value.
2002-10-02 Roger Sayle <roger@eyesopen.com>
PR optimization/6627
......@@ -98,7 +105,7 @@
* class.c (check_field_decls): Changed warning about const member
variables so that it doesn't get issued for a class aggregate.
2002-10-01 Mark Mitchell <mark@codesourcery.com>
* decl.c (cp_finish_decl): Make sure array types are laid out,
......@@ -181,12 +188,12 @@
(dfs_unuse_fields): Likewise.
* tree.c (pod_type_p): Handle error_mark_node.
(zero_init_p): Likewise.
* typeck.c (lookup_anon_field): Skip FIELD_DECLs for base
* typeck.c (lookup_anon_field): Skip FIELD_DECLs for base
subobjects.
* typeck2.c (store_init_value): Remove #if 0'd code.
(force_store_init_value): Remove.
(process_init_constructor): Use build_zero_init.
2002-09-29 Nathan Sidwell <nathan@codesourcery.com>
PR c++/7788
......@@ -214,7 +221,7 @@
even number of bytes when computing the size without virtual
bases.
* cp/cp-tree.h (abi_version_at_least): New macro.
2002-09-21 Kazu Hirata <kazu@cs.umass.edu>
* ChangeLog: Follow spelling conventions.
......
gcc/cp/decl.c
......@@ -7290,14 +7290,8 @@ start_decl (declarator, declspecs, initialized, attributes, prefix_attributes)
switch (TREE_CODE (decl))
{
case TYPE_DECL:
/* typedef foo = bar means give foo the same type as bar.
We haven't parsed bar yet, so `cp_finish_decl' will fix that up.
Any other case of an initialization in a TYPE_DECL is an error. */
if (pedantic || list_length (declspecs) > 1)
{
error ("typedef `%D' is initialized", decl);
initialized = 0;
}
error ("typedef `%D' is initialized", decl);
initialized = 0;
break;
case FUNCTION_DECL:
......@@ -8156,12 +8150,6 @@ cp_finish_decl (decl, init, asmspec_tree, flags)
/* Take care of TYPE_DECLs up front. */
if (TREE_CODE (decl) == TYPE_DECL)
{
if (init && DECL_INITIAL (decl))
{
/* typedef foo = bar; store the type of bar as the type of foo. */
TREE_TYPE (decl) = type = TREE_TYPE (init);
DECL_INITIAL (decl) = init = NULL_TREE;
}
if (type != error_mark_node
&& IS_AGGR_TYPE (type) && DECL_NAME (decl))
{
......@@ -11365,9 +11353,6 @@ grokdeclarator (declarator, declspecs, decl_context, initialized, attrlist)
bad_specifiers (decl, "type", virtualp, quals != NULL_TREE,
inlinep, friendp, raises != NULL_TREE);
if (initialized)
error ("typedef declaration includes an initializer");
return decl;
}
......
gcc/doc/extend.texi
......@@ -427,7 +427,6 @@ extensions, accepted by GCC in C89 mode and in C++.
* Labels as Values:: Getting pointers to labels, and computed gotos.
* Nested Functions:: As in Algol and Pascal, lexical scoping of functions.
* Constructing Calls:: Dispatching a call to another function.
* Naming Types:: Giving a name to the type of some expression.
* Typeof:: @code{typeof}: referring to the type of an expression.
* Lvalues:: Using @samp{?:}, @samp{,} and casts in lvalues.
* Conditionals:: Omitting the middle operand of a @samp{?:} expression.
......@@ -538,8 +537,7 @@ the value of an enumeration constant, the width of a bit-field, or
the initial value of a static variable.
If you don't know the type of the operand, you can still do this, but you
must use @code{typeof} (@pxref{Typeof}) or type naming (@pxref{Naming
Types}).
must use @code{typeof} (@pxref{Typeof}).
Statement expressions are not supported fully in G++, and their fate
there is unclear. (It is possible that they will become fully supported
......@@ -888,29 +886,6 @@ the containing function. You should specify, for @var{result}, a value
returned by @code{__builtin_apply}.
@end deftypefn
@node Naming Types
@section Naming an Expression's Type
@cindex naming types
You can give a name to the type of an expression using a @code{typedef}
declaration with an initializer. Here is how to define @var{name} as a
type name for the type of @var{exp}:
@example
typedef @var{name} = @var{exp};
@end example
This is useful in conjunction with the statements-within-expressions
feature. Here is how the two together can be used to define a safe
``maximum'' macro that operates on any arithmetic type:
@example
#define max(a,b) \
(@{typedef _ta = (a), _tb = (b); \
_ta _a = (a); _tb _b = (b); \
_a > _b ? _a : _b; @})
@end example
@cindex underscores in variables in macros
@cindex @samp{_} in variables in macros
@cindex local variables in macros
......@@ -962,6 +937,21 @@ A @code{typeof}-construct can be used anywhere a typedef name could be
used. For example, you can use it in a declaration, in a cast, or inside
of @code{sizeof} or @code{typeof}.
@code{typeof} is often useful in conjunction with the
statements-within-expressions feature. Here is how the two together can
be used to define a safe ``maximum'' macro that operates on any
arithmetic type and evaluates each of its arguments exactly once:
@example
#define max(a,b) \
(@{ typeof (a) _a = (a); \
typeof (b) _b = (b); \
_a > _b ? _a : _b; @})
@end example
@noindent
Some more examples of the use of @code{typeof}:
@itemize @bullet
@item
This declares @code{y} with the type of what @code{x} points to.
......@@ -1011,6 +1001,26 @@ Thus, @code{array (pointer (char), 4)} is the type of arrays of 4
pointers to @code{char}.
@end itemize
@emph{Compatibility Note:} In addition to @code{typeof}, GCC 2 supported
a more limited extension which permitted one to write
@example
typedef @var{T} = @var{expr};
@end example
@noindent
with the effect of declaring @var{T} to have the type of the expression
@var{expr}. This extension does not work with GCC 3 (versions between
3.0 and 3.2 will crash; 3.2.1 and later give an error). Code which
relies on it should be rewritten to use @code{typeof}:
@example
typedef typeof(@var{expr}) @var{T};
@end example
@noindent
This will work with all versions of GCC@.
@node Lvalues
@section Generalized Lvalues
@cindex compound expressions as lvalues
......@@ -6827,12 +6837,12 @@ the minimum value of variables @var{i} and @var{j}.
However, side effects in @code{X} or @code{Y} may cause unintended
behavior. For example, @code{MIN (i++, j++)} will fail, incrementing
the smaller counter twice. A GNU C extension allows you to write safe
macros that avoid this kind of problem (@pxref{Naming Types,,Naming an
Expression's Type}). However, writing @code{MIN} and @code{MAX} as
macros also forces you to use function-call notation for a
fundamental arithmetic operation. Using GNU C++ extensions, you can
write @w{@samp{int min = i <? j;}} instead.
the smaller counter twice. The GNU C @code{typeof} extension allows you
to write safe macros that avoid this kind of problem (@pxref{Typeof}).
However, writing @code{MIN} and @code{MAX} as macros also forces you to
use function-call notation for a fundamental arithmetic operation.
Using GNU C++ extensions, you can write @w{@samp{int min = i <? j;}}
instead.
Since @code{<?} and @code{>?} are built into the compiler, they properly
handle expressions with side-effects; @w{@samp{int min = i++ <? j++;}}
......
gcc/testsuite/ChangeLog
2002-10-09 Zack Weinberg <zack@codesourcery.com>
* g++.dg/ext/typedef-init.C: New test.
* gcc.dg/typedef-init.c: New test.
2002-10-09 Neil Booth <neil@daikokuya.co.uk>
* gcc.dg/cpp/paste13.c: New test.
......
gcc/testsuite/g++.dg/ext/typedef-init.C 0 → 100644
/* { dg-do compile } */
/* { dg-options "-fpermissive" } // suppress default -pedantic-errors */
/* This code used to be a legitimate, if dubious, extension. However,
it's been broken since GCC 3.0 (caused ICE) and we have now removed
the extension. See PR c/7353.
C++ issues a warning in addition to the error, since this construct
appears to be a case of implicit int (forbidden in std. C++) until
we get to the equals sign. */
typedef A = 0; /* { dg-error "initialized" "typedef A = B" } */
/* { dg-warning "no type" "also warns" { target *-*-* } 12 } */
A a; /* { dg-bogus "" "no error cascade" } */
gcc/testsuite/gcc.dg/typedef-init.c 0 → 100644
/* { dg-do compile } */
/* { dg-options "-std=gnu89" } // suppress default -pedantic-errors */
/* This code used to be a legitimate, if dubious, extension. However,
it's been broken since GCC 3.0 (caused ICE) and we have now removed
the extension. See PR c/7353. */
typedef A = 0; /* { dg-error "initialized" "typedef A = B" } */
A a; /* { dg-bogus "" "no error cascade" } */
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