Disambiguation of '[[':

 * In C++11, '[[' is ill-formed unless it starts an attribute-specifier. Reject
   array sizes and array indexes which begin with a lambda-expression. Recover by
   parsing the lambda as a lambda.
 * In Objective-C++11, either '[' could be the start of a message-send.
   Fully disambiguate this case: it turns out that the grammars of message-sends,
   lambdas and attributes do not actually overlap. Accept any occurrence of '[['
   where either '[' starts a message send, but reject a lambda in an array index
   just like in C++11 mode.

Implement a couple of changes to the attribute wording which occurred after our
attributes implementation landed:
 * In a function-declaration, the attributes go after the exception specification,
   not after the right paren.
 * A reference type can have attributes applied.
 * An 'identifier' in an attribute can also be a keyword. Support for alternative
   tokens (iso646 keywords) in attributes to follow.

And some bug fixes:
 * Parse attributes after declarator-ids, even if they are not simple identifiers.
 * Do not accept attributes after a parenthesized declarator.
 * Accept attributes after an array size in a new-type-id.
 * Partially disamiguate 'delete' followed by a lambda. More work is required
   here for the case where the lambda-introducer is '[]'.

llvm-svn: 154369

5 files changed, 100 insertions, 5 deletions

diff --git a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.grammar/p6.cpp b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.grammar/p6.cpp
new file mode 100644
index 00000000000..f9702ba7ccb
--- /dev/null
+++ b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.grammar/p6.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -std=c++11 -verify %s
+
+namespace std_example {
+
+int p[10];
+void f() {
+  int x = 42, y[5];
+  // FIXME: Produce a better diagnostic for this case.
+  int(p[[x] { return x; }()]); // expected-error {{expected ']'}}
+  y[[] { return 2; }()] = 2; // expected-error {{consecutive left square brackets}}
+}
+
+}
diff --git a/clang/test/Parser/cxx0x-attributes.cpp b/clang/test/Parser/cxx0x-attributes.cpp
index 198da778cd0..b20873509b6 100644
--- a/clang/test/Parser/cxx0x-attributes.cpp
+++ b/clang/test/Parser/cxx0x-attributes.cpp
@@ -5,11 +5,17 @@
 int [[]] between_attr;
 int after_attr [[]];
 int * [[]] ptr_attr;
+int & [[]] ref_attr = after_attr;
+int && [[]] rref_attr = 0;
 int array_attr [1] [[]];
 alignas(8) int aligned_attr;
 [[test::valid(for 42 [very] **** '+' symbols went on a trip; the end.)]]
   int garbage_attr;
 void fn_attr () [[]];
+void noexcept_fn_attr () noexcept [[]];
+struct MemberFnOrder {
+  virtual void f() const volatile && noexcept [[]] final = 0;
+};
 class [[]] class_attr {};
 extern "C++" [[]] int extern_attr;
 template <typename T> [[]] void template_attr ();
@@ -17,10 +23,10 @@ template <typename T> [[]] void template_attr ();
 
 int comma_attr [[,]]; // expected-error {{expected identifier}}
 int scope_attr [[foo::]]; // expected-error {{expected identifier}}
+int (paren_attr) [[]]; // expected-error {{an attribute list cannot appear here}}
 unsigned [[]] int attr_in_decl_spec; // expected-error {{expected unqualified-id}}
-int & [[]] ref_attr = after_attr; // expected-error {{an attribute list cannot appear here}}
 class foo {
-  void after_const_attr () const [[]]; // expected-error {{expected body of lambda expression}}
+  void const_after_attr () [[]] const; // expected-error {{expected ';'}}
 };
 extern "C++" [[]] { } // expected-error {{an attribute list cannot appear here}}
 [[]] template <typename T> void before_template_attr (); // expected-error {{an attribute list cannot appear here}}
@@ -58,6 +64,9 @@ void foo () {
   [[]] try {
   } [[]] catch (...) { // expected-error {{an attribute list cannot appear here}}
   }
-  
+  struct S { int arr[2]; } s;
+  (void)s.arr[ [] { return 0; }() ]; // expected-error {{C++11 only allows consecutive left square brackets when introducing an attribute}}
+  int n = __builtin_offsetof(S, arr[ [] { return 0; }() ]); // expected-error {{C++11 only allows consecutive left square brackets when introducing an attribute}}
+
   [[]] return;
 }
diff --git a/clang/test/Parser/objcxx11-attributes.mm b/clang/test/Parser/objcxx11-attributes.mm
new file mode 100644
index 00000000000..719cdcc32f4
--- /dev/null
+++ b/clang/test/Parser/objcxx11-attributes.mm
@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+
+@interface X {}
++ (X*) alloc;
+- (X*) init;
+- (int) getSize;
+- (void) setSize: (int) size;
+- (X*) getSelf;
+@end
+
+void f(X *noreturn) {
+  // An array size which is computed by a message send is OK.
+  int a[ [noreturn getSize] ];
+
+  // ... but is interpreted as an attribute where possible.
+  int b[ [noreturn] ]; // expected-warning {{'noreturn' only applies to function types}}
+
+  int c[ [noreturn getSize] + 1 ];
+
+  // An array size which is computed by a lambda is not OK.
+  int d[ [noreturn] { return 3; } () ]; // expected-error {{expected ']'}} expected-warning {{'noreturn' only applies}}
+
+  // A message send which contains a message send is OK.
+  [ [ X alloc ] init ];
+  [ [ int(), noreturn getSelf ] getSize ]; // expected-warning {{unused}}
+
+  // A message send which contains a lambda is OK.
+  [ [noreturn] { return noreturn; } () setSize: 4 ];
+  [ [bitand] { return noreturn; } () setSize: 5 ];
+  [[[[] { return [ X alloc ]; } () init] getSelf] getSize];
+
+  // An attribute is OK.
+  [[]];
+  [[int(), noreturn]];
+  [[class, test(foo 'x' bar),,,]];
+}
+
+template<typename...Ts> void f(Ts ...x) {
+  [[test::foo(bar, baz)...]];
+  [[used(x)...]];
+  [[x...] { return [ X alloc ]; }() init];
+}
diff --git a/clang/test/SemaCXX/new-delete-0x.cpp b/clang/test/SemaCXX/new-delete-0x.cpp
new file mode 100644
index 00000000000..dcc2e9b8b12
--- /dev/null
+++ b/clang/test/SemaCXX/new-delete-0x.cpp
@@ -0,0 +1,32 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s -triple=i686-pc-linux-gnu -std=c++11
+
+using size_t = decltype(sizeof(0));
+struct noreturn_t {} constexpr noreturn = {};
+
+void *operator new [[noreturn]] (size_t, noreturn_t);
+void operator delete [[noreturn]] (void*, noreturn_t);
+
+void good_news()
+{
+  auto p = new int[2][[]];
+  auto q = new int[[]][2];
+  auto r = new int*[[]][2][[]];
+  auto s = new (int(*[[]])[2][[]]);
+}
+
+void bad_news(int *ip)
+{
+  // attribute-specifiers can go almost anywhere in a new-type-id...
+  auto r = new int[[]{return 1;}()][2]; // expected-error {{expected ']'}}
+  auto s = new int*[[]{return 1;}()][2]; // expected-error {{expected ']'}}
+  // ... but not here:
+  auto t = new (int(*)[[]]); // expected-error {{an attribute list cannot appear here}}
+  auto u = new (int(*)[[]{return 1;}()][2]); // expected-error {{C++11 only allows consecutive left square brackets when introducing an attribute}} expected-error {{variably modified type}}
+}
+
+void good_deletes()
+{
+  delete [&]{ return (int*)0; }();
+  // FIXME: This appears to be legal.
+  delete []{ return (int*)0; }(); // unexpected-error {{expected expression}}
+}
diff --git a/clang/test/SemaCXX/new-delete.cpp b/clang/test/SemaCXX/new-delete.cpp
index 88d85ca792e..e77e3d652f4 100644
--- a/clang/test/SemaCXX/new-delete.cpp
+++ b/clang/test/SemaCXX/new-delete.cpp
@@ -102,8 +102,7 @@ void good_deletes()
 void bad_deletes()
 {
   delete 0; // expected-error {{cannot delete expression of type 'int'}}
-  delete [0] (int*)0; // expected-error {{expected ']'}} \
-                      // expected-note {{to match this '['}}
+  delete [0] (int*)0; // expected-error {{expected expression}}
   delete (void*)0; // expected-warning {{cannot delete expression with pointer-to-'void' type 'void *'}}
   delete (T*)0; // expected-warning {{deleting pointer to incomplete type}}
   ::S::delete (int*)0; // expected-error {{expected unqualified-id}}