Re: C++ PATCH to add capture initializers to -std=c++1y
On 04/22/2013 03:19 PM, Jason Merrill wrote:
The only thing missing from our implementation is support for
list-initialization as well as = initialization; I'll add that soon.
These patches add that and parenthesized initializers, and also conform
to the proposal that init-captures be nameable in the closure object.
Tested x86_64-pc-linux-gnu, applying to trunk.
Jason
commit 91c5b39225cda83fe8bdb299fb30b85702059b6b
Author: Jason Merrill ja...@redhat.com
Date: Tue Apr 23 23:28:50 2013 -0400
N3648: Allow braced and parenthesized initializers.
* parser.c (cp_parser_lambda_introducer): Use cp_parser_initializer.
* pt.c (tsubst) [DECLTYPE_TYPE]: Handle DECLTYPE_FOR_INIT_CAPTURE.
* semantics.c (lambda_capture_field_type): Use do_auto_deduction.
(add_capture): Collapse a parenthesized initializer into a single
expression.
* cp-tree.h (DECLTYPE_FOR_INIT_CAPTURE): New.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index d96340a..6254c7d 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -90,6 +90,7 @@ c-common.h, not after.
LAMBDA_EXPR_MUTABLE_P (in LAMBDA_EXPR)
DECL_FINAL_P (in FUNCTION_DECL)
QUALIFIED_NAME_IS_TEMPLATE (in SCOPE_REF)
+ DECLTYPE_FOR_INIT_CAPTURE (in DECLTYPE_TYPE)
2: IDENTIFIER_OPNAME_P (in IDENTIFIER_NODE)
ICS_THIS_FLAG (in _CONV)
DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (in VAR_DECL)
@@ -97,6 +98,7 @@ c-common.h, not after.
TYPENAME_IS_RESOLVING_P (in TYPE_NAME_TYPE)
TARGET_EXPR_DIRECT_INIT_P (in TARGET_EXPR)
FNDECL_USED_AUTO (in FUNCTION_DECL)
+ DECLTYPE_FOR_LAMBDA_PROXY (in DECLTYPE_TYPE)
3: (TREE_REFERENCE_EXPR) (in NON_LVALUE_EXPR) (commented-out).
ICS_BAD_FLAG (in _CONV)
FN_TRY_BLOCK_P (in TRY_BLOCK)
@@ -3590,10 +3592,12 @@ more_aggr_init_expr_args_p (const aggr_init_expr_arg_iterator *iter)
(DECLTYPE_TYPE_CHECK (NODE))-type_common.string_flag
/* These flags indicate that we want different semantics from normal
- decltype: lambda capture just drops references, lambda proxies look
- through implicit dereference. */
+ decltype: lambda capture just drops references, init capture
+ uses auto semantics, lambda proxies look through implicit dereference. */
#define DECLTYPE_FOR_LAMBDA_CAPTURE(NODE) \
TREE_LANG_FLAG_0 (DECLTYPE_TYPE_CHECK (NODE))
+#define DECLTYPE_FOR_INIT_CAPTURE(NODE) \
+ TREE_LANG_FLAG_1 (DECLTYPE_TYPE_CHECK (NODE))
#define DECLTYPE_FOR_LAMBDA_PROXY(NODE) \
TREE_LANG_FLAG_2 (DECLTYPE_TYPE_CHECK (NODE))
@@ -5780,7 +5784,7 @@ extern tree finish_trait_expr (enum cp_trait_kind, tree, tree);
extern tree build_lambda_expr (void);
extern tree build_lambda_object (tree);
extern tree begin_lambda_type (tree);
-extern tree lambda_capture_field_type (tree);
+extern tree lambda_capture_field_type (tree, bool);
extern tree lambda_return_type (tree);
extern tree lambda_proxy_type (tree);
extern tree lambda_function (tree);
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 0456dd2..cb26292 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -8548,17 +8548,18 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
}
/* Find the initializer for this capture. */
- if (cp_lexer_next_token_is (parser-lexer, CPP_EQ))
+ if (cp_lexer_next_token_is (parser-lexer, CPP_EQ)
+ || cp_lexer_next_token_is (parser-lexer, CPP_OPEN_PAREN)
+ || cp_lexer_next_token_is (parser-lexer, CPP_OPEN_BRACE))
{
- /* An explicit expression exists. */
- cp_lexer_consume_token (parser-lexer);
+ bool direct, non_constant;
+ /* An explicit initializer exists. */
if (cxx_dialect cxx1y)
pedwarn (input_location, 0,
lambda capture initializers
only available with -std=c++1y or -std=gnu++1y);
- capture_init_expr = cp_parser_assignment_expression (parser,
- /*cast_p=*/true,
- idk);
+ capture_init_expr = cp_parser_initializer (parser, direct,
+ non_constant);
explicit_init_p = true;
}
else
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 5f4d7a2..36e839f 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -11825,7 +11825,8 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
--c_inhibit_evaluation_warnings;
if (DECLTYPE_FOR_LAMBDA_CAPTURE (t))
- type = lambda_capture_field_type (type);
+ type = lambda_capture_field_type (type,
+ DECLTYPE_FOR_INIT_CAPTURE (t));
else if (DECLTYPE_FOR_LAMBDA_PROXY (t))
type = lambda_proxy_type (type);
else
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index d4f0f82..da66168 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -9123,14 +9123,22 @@ lambda_function (tree lambda)
The caller should add REFERENCE_TYPE for capture by reference. */
tree
-lambda_capture_field_type (tree expr)
+lambda_capture_field_type (tree expr, bool explicit_init_p)
{
- tree type = non_reference (unlowered_expr_type
C++ PATCH to add capture initializers to -std=c++1y
At the Bristol C++ meeting we voted to accept generalized lambda capture
initializers (e.g. [x = 42, y = std::move(y)]{ ... }), which were part
of the initial implementation of lambdas in GCC, so initial support for
C++1y is just a matter of checking cxx_dialect to avoid the pedwarn.
The only thing missing from our implementation is support for
list-initialization as well as = initialization; I'll add that soon.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit a920644105779dceffd5912822b10b331457a227
Author: Jason Merrill ja...@redhat.com
Date: Mon Apr 22 12:56:01 2013 -0400
N3648
* parser.c (cp_parser_lambda_introducer): Make lambda capture init
pedwarn unconditional except in C++1y mode.
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 1893482..1fbc9bd 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -8518,9 +8518,10 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
{
/* An explicit expression exists. */
cp_lexer_consume_token (parser-lexer);
- pedwarn (input_location, OPT_Wpedantic,
- ISO C++ does not allow initializers
- in lambda expression capture lists);
+ if (cxx_dialect cxx1y)
+ pedwarn (input_location, 0,
+ lambda capture initializers
+ only available with -std=c++1y or -std=gnu++1y);
capture_init_expr = cp_parser_assignment_expression (parser,
/*cast_p=*/true,
idk);
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-deduce-ext.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-deduce-ext.C
deleted file mode 100644
index 9b5ab79..000
--- a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-deduce-ext.C
+++ /dev/null
@@ -1,27 +0,0 @@
-// Testcase for an extension to allow return type deduction when the lambda
-// contains more than just a single return-statement.
-
-// { dg-options -std=c++0x }
-// { dg-do run }
-
-bool b;
-template class T
-T f (T t)
-{
- return [=] {
-auto i = t+1;
-if (b)
- return i+1;
-else
- return i+1;
- }();
-}
-
-int main()
-{
- // Pointless, but well-formed.
- [] { return 1; return 2; }();
-
- if (f(1) != 3)
-return 1;
-}
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-init.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-init.C
deleted file mode 100644
index 03c94e9..000
--- a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-init.C
+++ /dev/null
@@ -1,8 +0,0 @@
-// Test for the explicit initializer extension
-// { dg-options -std=c++0x }
-
-int main()
-{
- int j = [i = 2]{sizeof(i); return i;}();
- return (j != 2);
-}
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-deduce-mult.C b/gcc/testsuite/g++.dg/cpp1y/lambda-deduce-mult.C
new file mode 100644
index 000..1181a80
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-deduce-mult.C
@@ -0,0 +1,27 @@
+// Testcase for an extension to allow return type deduction when the lambda
+// contains more than just a single return-statement.
+
+// { dg-options -std=c++1y }
+// { dg-do run }
+
+bool b;
+template class T
+T f (T t)
+{
+ return [=] {
+auto i = t+1;
+if (b)
+ return i+1;
+else
+ return i+1;
+ }();
+}
+
+int main()
+{
+ // Pointless, but well-formed.
+ [] { return 1; return 2; }();
+
+ if (f(1) != 3)
+return 1;
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init.C
new file mode 100644
index 000..a443642
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init.C
@@ -0,0 +1,8 @@
+// Test for the explicit initializer extension of C++1y
+// { dg-options -std=c++1y }
+
+int main()
+{
+ int j = [i = 2]{sizeof(i); return i;}();
+ return (j != 2);
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init1.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init1.C
new file mode 100644
index 000..6411fca
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init1.C
@@ -0,0 +1,13 @@
+// N3648: capture init
+// { dg-options -std=c++1y -w }
+// { dg-do run }
+
+int main()
+{
+ int x = 41;
+ auto r = [x = x+1]{ return x; }();
+ if (r != 42) __builtin_abort();
+
+ static auto *p = r;
+ [x=r]{ if (x != p) __builtin_abort(); }();
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init2.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init2.C
new file mode 100644
index 000..068621d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init2.C
@@ -0,0 +1,13 @@
+// N3648: redundancy and capture init
+// { dg-options -std=c++1y -pedantic-errors }
+
+int main()
+{
+ int x = 42;
+ [=,x]{}; // { dg-error redundant }
+ [=,x]{};
+ [,x]{}; // { dg-error redundant }
+ [,x]{};
+ [=,x=24]{};
+ [,r=x]{};
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/lambda-init3.C b/gcc/testsuite/g++.dg/cpp1y/lambda-init3.C
new file mode 100644
index 000..9044be6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/lambda-init3.C
@@ -0,0 +1,11 @@
+// N3648: capture init at non-block scope
+// { dg-options -std=c++1y -w }
+// { dg-do run }
+
+int i = 42;
+int j = [x=i]{ return x; }();
+
+int
