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RFA: PR 2409
- From: Tom Tromey <tromey at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Wed, 20 Aug 2008 08:06:34 -0600
- Subject: RFA: PR 2409
- Reply-to: tromey at redhat dot com
This patch fixes PR 2409.
The bug is that gdb does not accept 'void (**) (void)' as a type.
To fix this I made the c-exp.y grammar look a bit more like C grammar
in GCC. I took the name of the new production from g++.
While doing this I found it difficult to correctly build qualified
pointer types. Previously we handled this by repeated calls to
follow_types, so we'd only see tp_const at the top-of-stack. This
doesn't work with the new approach, since we can't call follow_types
from the abs_decl or ptr_operator productions.
To fix this I added some new APIs to insert pointers and qualifiers at
the bottom of the stack. These don't affect any other language. This
is a bit strange.
While doing this I noticed a few possible cleanups. First, objc-exp.y
is an old copy of c-exp.y that has diverged over the years. I think
it would be better to merge it into c-exp.y. Second, f-exp.y has its
own variant of follow_types; this could be merged -- it is the only
reason that pop_type has to be non-static. I haven't attempted either
of these. Finally, I noticed a few missing and/or incorrect things; I
filed PRs for these.
Built and regtested on x86-64. A few new test cases included.
Ok?
Tom
:ADDPATCH expressions:
2008-08-20 Tom Tromey <tromey@redhat.com>
PR gdb/2409:
* parser-defs.h (insert_type, insert_type_address_space): Declare.
(push_type_address_space): Remove.
* parse.c (insert_into_type_stack): New function.
(insert_type): Likewise.
(insert_type_address_space): Rename from push_type_address_space.
Insert tp_space_identifier.
* c-exp.y (ptr_operator): New production.
(abs_decl): Use ptr_operator.
(space_identifier): Call insert_type_address_space.
(ptype): Don't use const_or_volatile_or_space_identifier.
(const_or_volatile_noopt): Call insert_type.
2008-08-20 Tom Tromey <tromey@redhat.com>
* gdb.base/whatis.exp: Add tests.
diff --git a/gdb/c-exp.y b/gdb/c-exp.y
index bd04dc2..79034c8 100644
--- a/gdb/c-exp.y
+++ b/gdb/c-exp.y
@@ -162,7 +162,7 @@ static int parse_number (char *, int, int, YYSTYPE *);
/* %type <bval> block */
/* Fancy type parsing. */
-%type <voidval> func_mod direct_abs_decl abs_decl
+%type <voidval> func_mod direct_abs_decl abs_decl ptr_operator
%type <tval> ptype
%type <lval> array_mod
@@ -771,9 +771,7 @@ variable: name_not_typename
;
space_identifier : '@' NAME
- { push_type_address_space (copy_name ($2.stoken));
- push_type (tp_space_identifier);
- }
+ { insert_type_address_space (copy_name ($2.stoken)); }
;
const_or_volatile: const_or_volatile_noopt
@@ -792,14 +790,23 @@ const_or_volatile_or_space_identifier:
|
;
-abs_decl: '*'
- { push_type (tp_pointer); $$ = 0; }
- | '*' abs_decl
- { push_type (tp_pointer); $$ = $2; }
+ptr_operator:
+ ptr_operator '*'
+ { insert_type (tp_pointer); }
+ const_or_volatile_or_space_identifier
+ { $$ = 0; }
+ | '*'
+ { insert_type (tp_pointer); }
+ const_or_volatile_or_space_identifier
+ { $$ = 0; }
| '&'
- { push_type (tp_reference); $$ = 0; }
- | '&' abs_decl
- { push_type (tp_reference); $$ = $2; }
+ { insert_type (tp_reference); $$ = 0; }
+ | '&' ptr_operator
+ { insert_type (tp_reference); $$ = 0; }
+ ;
+
+abs_decl: ptr_operator direct_abs_decl
+ | ptr_operator
| direct_abs_decl
;
@@ -1044,7 +1051,7 @@ nonempty_typelist
;
ptype : typebase
- | ptype const_or_volatile_or_space_identifier abs_decl const_or_volatile_or_space_identifier
+ | ptype abs_decl
{ $$ = follow_types ($1); }
;
@@ -1053,13 +1060,13 @@ const_and_volatile: CONST_KEYWORD VOLATILE_KEYWORD
;
const_or_volatile_noopt: const_and_volatile
- { push_type (tp_const);
- push_type (tp_volatile);
+ { insert_type (tp_const);
+ insert_type (tp_volatile);
}
| CONST_KEYWORD
- { push_type (tp_const); }
+ { insert_type (tp_const); }
| VOLATILE_KEYWORD
- { push_type (tp_volatile); }
+ { insert_type (tp_volatile); }
;
name : NAME { $$ = $1.stoken; }
diff --git a/gdb/parse.c b/gdb/parse.c
index b587ec3..c4bbf71 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -1153,6 +1153,49 @@ check_type_stack_depth (void)
}
}
+/* A helper function for insert_type and insert_type_address_space.
+ This does work of expanding the type stack and inserting the new
+ element, ELEMENT, into the stack at location SLOT. */
+
+static void
+insert_into_type_stack (int slot, union type_stack_elt element)
+{
+ check_type_stack_depth ();
+
+ if (slot < type_stack_depth)
+ memmove (&type_stack[slot + 1], &type_stack[slot],
+ (type_stack_depth - slot) * sizeof (union type_stack_elt));
+ type_stack[slot] = element;
+ ++type_stack_depth;
+}
+
+/* Insert a new type, TP, at the bottom of the type stack. If TP is
+ tp_pointer or tp_reference, it is inserted at the bottom. If TP is
+ a qualifier, it is inserted at slot 1 (just above a previous
+ tp_pointer) if there is anything on the stack, or simply pushed if
+ the stack is empty. Other values for TP are invalid. */
+
+void
+insert_type (enum type_pieces tp)
+{
+ union type_stack_elt element;
+ int slot;
+
+ gdb_assert (tp == tp_pointer || tp == tp_reference
+ || tp == tp_const || tp == tp_volatile);
+
+ /* If there is anything on the stack (we know it will be a
+ tp_pointer), insert the qualifier above it. Otherwise, simply
+ push this on the top of the stack. */
+ if (type_stack_depth && (tp == tp_const || tp == tp_volatile))
+ slot = 1;
+ else
+ slot = 0;
+
+ element.piece = tp;
+ insert_into_type_stack (slot, element);
+}
+
void
push_type (enum type_pieces tp)
{
@@ -1167,10 +1210,32 @@ push_type_int (int n)
type_stack[type_stack_depth++].int_val = n;
}
+/* Insert a tp_space_identifier and the corresponding address space
+ value into the stack. STRING is the name of an address space, as
+ recognized by address_space_name_to_int. If the stack is empty,
+ the new elements are simply pushed. If the stack is not empty,
+ this function assumes that the first item on the stack is a
+ tp_pointer, and the new values are inserted above the first
+ item. */
+
void
-push_type_address_space (char *string)
+insert_type_address_space (char *string)
{
- push_type_int (address_space_name_to_int (string));
+ union type_stack_elt element;
+ int slot;
+
+ /* If there is anything on the stack (we know it will be a
+ tp_pointer), insert the address space qualifier above it.
+ Otherwise, simply push this on the top of the stack. */
+ if (type_stack_depth)
+ slot = 1;
+ else
+ slot = 0;
+
+ element.piece = tp_space_identifier;
+ insert_into_type_stack (slot, element);
+ element.int_val = address_space_name_to_int (string);
+ insert_into_type_stack (slot, element);
}
enum type_pieces
diff --git a/gdb/parser-defs.h b/gdb/parser-defs.h
index f49ff9e..b1380a3 100644
--- a/gdb/parser-defs.h
+++ b/gdb/parser-defs.h
@@ -148,11 +148,13 @@ extern int end_arglist (void);
extern char *copy_name (struct stoken);
+extern void insert_type (enum type_pieces);
+
extern void push_type (enum type_pieces);
extern void push_type_int (int);
-extern void push_type_address_space (char *);
+extern void insert_type_address_space (char *);
extern enum type_pieces pop_type (void);
diff --git a/gdb/testsuite/gdb.base/whatis.exp b/gdb/testsuite/gdb.base/whatis.exp
index d480995..ec75d3f 100644
--- a/gdb/testsuite/gdb.base/whatis.exp
+++ b/gdb/testsuite/gdb.base/whatis.exp
@@ -471,3 +471,17 @@ gdb_test "whatis char_addr" \
gdb_test "whatis a_char_addr" \
"type = char_addr" \
"whatis applied to variable defined by typedef"
+
+# Regression tests for PR 2409.
+
+gdb_test "whatis void (**)()" \
+ "type = void \\(\\*\\*\\)\\(\\)" \
+ "whatis applied to pointer to pointer to function"
+
+gdb_test "whatis void (** const)()" \
+ "type = void \\(\\*\\*\\ const)\\(\\)" \
+ "whatis applied to const pointer to pointer to function"
+
+gdb_test "whatis void (* const *)()" \
+ "type = void \\(\\* const \\*\\)\\(\\)" \
+ "whatis applied to pointer to const pointer to function"