* C++ PATCH for c++/49003 (DR 1207, use of 'this' in trailing return type)
@ 2011-06-29 21:36 Jason Merrill
2011-07-04 21:41 ` Jason Merrill
0 siblings, 1 reply; 2+ messages in thread
From: Jason Merrill @ 2011-06-29 21:36 UTC (permalink / raw)
To: gcc-patches List
[-- Attachment #1: Type: text/plain, Size: 168 bytes --]
This patch adds support for use of 'this' (implicitly or explicitly) in
the trailing-return-type of a member function.
Tested x86_64-pc-linux-gnu, applying to trunk.
[-- Attachment #2: 49003.patch --]
[-- Type: text/x-patch, Size: 5638 bytes --]
commit 8154a9854f1d5ff3407af1707d112899eb39f013
Author: Jason Merrill <jason@redhat.com>
Date: Wed Jun 29 15:19:46 2011 -0400
DR 1207
PR c++/49003
* cp-tree.h (struct saved_scope): Add x_current_class_ptr,
x_current_class_ref.
(current_class_ptr, current_class_ref): Use them.
* decl.c (build_this_parm): Handle getting the class type.
* parser.c (cp_parser_late_return_type_opt): Set up 'this'
for use within the trailing return type.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 55c88e3..ef25c97 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -953,6 +953,10 @@ struct GTY(()) saved_scope {
struct cp_binding_level *x_previous_class_level;
tree x_saved_tree;
+ /* Only used for uses of this in trailing return type. */
+ tree x_current_class_ptr;
+ tree x_current_class_ref;
+
int x_processing_template_decl;
int x_processing_specialization;
BOOL_BITFIELD x_processing_explicit_instantiation : 1;
@@ -1070,12 +1074,14 @@ struct GTY(()) language_function {
PARM_DECL for the `this' pointer. The current_class_ref is an
expression for `*this'. */
-#define current_class_ptr \
- (cfun && cp_function_chain \
- ? cp_function_chain->x_current_class_ptr : NULL_TREE)
-#define current_class_ref \
- ((cfun && cp_function_chain) \
- ? cp_function_chain->x_current_class_ref : NULL_TREE)
+#define current_class_ptr \
+ (*(cfun && cp_function_chain \
+ ? &cp_function_chain->x_current_class_ptr \
+ : &scope_chain->x_current_class_ptr))
+#define current_class_ref \
+ (*(cfun && cp_function_chain \
+ ? &cp_function_chain->x_current_class_ref \
+ : &scope_chain->x_current_class_ref))
/* The EH_SPEC_BLOCK for the exception-specifiers for the current
function, if any. */
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index b8435a6..94d686d 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7001,7 +7001,14 @@ build_this_parm (tree type, cp_cv_quals quals)
tree parm;
cp_cv_quals this_quals;
- this_type = type_of_this_parm (type);
+ if (CLASS_TYPE_P (type))
+ {
+ this_type
+ = cp_build_qualified_type (type, quals & ~TYPE_QUAL_RESTRICT);
+ this_type = build_pointer_type (this_type);
+ }
+ else
+ this_type = type_of_this_parm (type);
/* The `this' parameter is implicitly `const'; it cannot be
assigned to. */
this_quals = (quals & TYPE_QUAL_RESTRICT) | TYPE_QUAL_CONST;
@@ -12675,6 +12682,7 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
cp_function_chain->x_current_class_ref
= cp_build_indirect_ref (t, RO_NULL, tf_warning_or_error);
+ /* Set this second to avoid shortcut in cp_build_indirect_ref. */
cp_function_chain->x_current_class_ptr = t;
/* Constructors and destructors need to know whether they're "in
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index f1b7976..d79326d 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -1696,7 +1696,7 @@ static cp_cv_quals cp_parser_cv_qualifier_seq_opt
static cp_virt_specifiers cp_parser_virt_specifier_seq_opt
(cp_parser *);
static tree cp_parser_late_return_type_opt
- (cp_parser *);
+ (cp_parser *, cp_cv_quals);
static tree cp_parser_declarator_id
(cp_parser *, bool);
static tree cp_parser_type_id
@@ -14968,7 +14968,7 @@ cp_parser_direct_declarator (cp_parser* parser,
virt_specifiers = cp_parser_virt_specifier_seq_opt (parser);
late_return
- = cp_parser_late_return_type_opt (parser);
+ = cp_parser_late_return_type_opt (parser, cv_quals);
/* Create the function-declarator. */
declarator = make_call_declarator (declarator,
@@ -15537,9 +15537,10 @@ cp_parser_virt_specifier_seq_opt (cp_parser* parser)
Returns the type indicated by the type-id. */
static tree
-cp_parser_late_return_type_opt (cp_parser* parser)
+cp_parser_late_return_type_opt (cp_parser* parser, cp_cv_quals quals)
{
cp_token *token;
+ tree type;
/* Peek at the next token. */
token = cp_lexer_peek_token (parser->lexer);
@@ -15550,7 +15551,23 @@ cp_parser_late_return_type_opt (cp_parser* parser)
/* Consume the ->. */
cp_lexer_consume_token (parser->lexer);
- return cp_parser_trailing_type_id (parser);
+ if (current_class_type)
+ {
+ /* DR 1207: 'this' is in scope in the trailing return type. */
+ tree this_parm = build_this_parm (current_class_type, quals);
+ gcc_assert (current_class_ptr == NULL_TREE);
+ current_class_ref
+ = cp_build_indirect_ref (this_parm, RO_NULL, tf_warning_or_error);
+ /* Set this second to avoid shortcut in cp_build_indirect_ref. */
+ current_class_ptr = this_parm;
+ }
+
+ type = cp_parser_trailing_type_id (parser);
+
+ if (current_class_type)
+ current_class_ptr = current_class_ref = NULL_TREE;
+
+ return type;
}
/* Parse a declarator-id.
diff --git a/gcc/testsuite/g++.dg/cpp0x/pr45908.C b/gcc/testsuite/g++.dg/cpp0x/pr45908.C
index 3a85088..45399b5 100644
--- a/gcc/testsuite/g++.dg/cpp0x/pr45908.C
+++ b/gcc/testsuite/g++.dg/cpp0x/pr45908.C
@@ -14,5 +14,5 @@ struct vector {
class block {
vector v;
auto end() const -> decltype(v.begin())
- { return v.begin(); } // { dg-error "could not convert" }
+ { return v.begin(); }
};
diff --git a/gcc/testsuite/g++.dg/cpp0x/trailing6.C b/gcc/testsuite/g++.dg/cpp0x/trailing6.C
new file mode 100644
index 0000000..3476e90
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/trailing6.C
@@ -0,0 +1,6 @@
+// PR c++/49003
+// { dg-options -std=c++0x }
+
+struct A {
+ auto a() const -> decltype(this) { return this; }
+};
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: C++ PATCH for c++/49003 (DR 1207, use of 'this' in trailing return type)
2011-06-29 21:36 C++ PATCH for c++/49003 (DR 1207, use of 'this' in trailing return type) Jason Merrill
@ 2011-07-04 21:41 ` Jason Merrill
0 siblings, 0 replies; 2+ messages in thread
From: Jason Merrill @ 2011-07-04 21:41 UTC (permalink / raw)
To: gcc-patches List
[-- Attachment #1: Type: text/plain, Size: 343 bytes --]
On 06/29/2011 05:15 PM, Jason Merrill wrote:
> This patch adds support for use of 'this' (implicitly or explicitly) in
> the trailing-return-type of a member function.
The above patch wasn't enough, though. The following patch fixes some
issues that arose with real uses, including mangling.
Tested x86_64-pc-linux-gnu, applying to trunk.
[-- Attachment #2: this-mangle.patch --]
[-- Type: text/x-patch, Size: 2959 bytes --]
commit ef43a979a3f46150f383b9deab70dd412d66f96b
Author: Jason Merrill <jason@redhat.com>
Date: Sun Jul 3 17:14:56 2011 -0400
DR 1207
PR c++/49589
* mangle.c (write_expression): Handle 'this'.
* parser.c (cp_parser_postfix_dot_deref_expression): Allow
incomplete *this.
* semantics.c (potential_constant_expression_1): Check that
DECL_CONTEXT is set on 'this'.
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 134c9ea..81b772f 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -2495,6 +2495,11 @@ write_expression (tree expr)
else if (TREE_CODE_CLASS (code) == tcc_constant
|| (abi_version_at_least (2) && code == CONST_DECL))
write_template_arg_literal (expr);
+ else if (code == PARM_DECL && DECL_ARTIFICIAL (expr))
+ {
+ gcc_assert (!strcmp ("this", IDENTIFIER_POINTER (DECL_NAME (expr))));
+ write_string ("fpT");
+ }
else if (code == PARM_DECL)
{
/* A function parameter used in a late-specified return type. */
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index d79326d..6bb15ed 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -5281,7 +5281,11 @@ cp_parser_postfix_dot_deref_expression (cp_parser *parser,
postfix_expression);
scope = NULL_TREE;
}
- else
+ /* Unlike the object expression in other contexts, *this is not
+ required to be of complete type for purposes of class member
+ access (5.2.5) outside the member function body. */
+ else if (scope != current_class_ref
+ && !(processing_template_decl && scope == current_class_type))
scope = complete_type_or_else (scope, NULL_TREE);
/* Let the name lookup machinery know that we are processing a
class member access expression. */
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index e29705c..619c058 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -7791,7 +7791,8 @@ potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
STRIP_NOPS (x);
if (is_this_parameter (x))
{
- if (DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)) && want_rval)
+ if (want_rval && DECL_CONTEXT (x)
+ && DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)))
{
if (flags & tf_error)
sorry ("use of the value of the object being constructed "
diff --git a/gcc/testsuite/g++.dg/abi/mangle48.C b/gcc/testsuite/g++.dg/abi/mangle48.C
new file mode 100644
index 0000000..dc9c492
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/mangle48.C
@@ -0,0 +1,23 @@
+// Testcase for 'this' mangling
+// { dg-options -std=c++0x }
+
+struct B
+{
+ template <class U> U f();
+};
+
+struct A
+{
+ B b;
+ // { dg-final { scan-assembler "_ZN1A1fIiEEDTcldtdtdefpT1b1fIT_EEEv" } }
+ template <class U> auto f() -> decltype (b.f<U>());
+ // { dg-final { scan-assembler "_ZN1A1gIiEEDTcldtptfpT1b1fIT_EEEv" } }
+ template <class U> auto g() -> decltype (this->b.f<U>());
+};
+
+int main()
+{
+ A a;
+ a.f<int>();
+ a.g<int>();
+}
[-- Attachment #3: this-demangle.patch --]
[-- Type: text/x-patch, Size: 2098 bytes --]
commit acbc60694bf95f13f9088ed4d5b3d18780aaf754
Author: Jason Merrill <jason@redhat.com>
Date: Mon Jul 4 10:44:29 2011 -0400
* cp-demangle.c (d_expression): Handle 'this'.
(d_print_comp) [DEMANGLE_COMPONENT_FUNCTION_PARAM]: Likewise.
diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c
index f136322..29badbb 100644
--- a/libiberty/cp-demangle.c
+++ b/libiberty/cp-demangle.c
@@ -2738,10 +2738,18 @@ d_expression (struct d_info *di)
/* Function parameter used in a late-specified return type. */
int index;
d_advance (di, 2);
- index = d_compact_number (di);
- if (index < 0)
- return NULL;
-
+ if (d_peek_char (di) == 'T')
+ {
+ /* 'this' parameter. */
+ d_advance (di, 1);
+ index = 0;
+ }
+ else
+ {
+ index = d_compact_number (di) + 1;
+ if (index == 0)
+ return NULL;
+ }
return d_make_function_param (di, index);
}
else if (IS_DIGIT (peek)
@@ -4400,9 +4408,17 @@ d_print_comp (struct d_print_info *dpi, int options,
return;
case DEMANGLE_COMPONENT_FUNCTION_PARAM:
- d_append_string (dpi, "{parm#");
- d_append_num (dpi, dc->u.s_number.number + 1);
- d_append_char (dpi, '}');
+ {
+ long num = dc->u.s_number.number;
+ if (num == 0)
+ d_append_string (dpi, "this");
+ else
+ {
+ d_append_string (dpi, "{parm#");
+ d_append_num (dpi, num);
+ d_append_char (dpi, '}');
+ }
+ }
return;
case DEMANGLE_COMPONENT_GLOBAL_CONSTRUCTORS:
diff --git a/libiberty/testsuite/demangle-expected b/libiberty/testsuite/demangle-expected
index 4980cf1..2dc74be 100644
--- a/libiberty/testsuite/demangle-expected
+++ b/libiberty/testsuite/demangle-expected
@@ -3905,6 +3905,10 @@ decltype ({parm#1}+{parm#2}) add<int, double>(int, double)
--format=gnu-v3
_Z4add3IidEDTclL_Z1gEfp_fp0_EET_T0_
decltype (g({parm#1}, {parm#2})) add3<int, double>(int, double)
+# 'this' test
+--format=gnu-v3
+_ZN1A1fIiEEDTcldtdtdefpT1b1fIT_EEEv
+decltype ((((*this).b).(f<int>))()) A::f<int>()
# new (2008) built in types test
--format=gnu-v3
_Z1fDfDdDeDhDsDi
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