Implement C++11 [dcl.align]p6-p8, and C11 6.7.5/7. This had to be split out of

the normal attribute-merging path, because we can't merge alignment attributes
without knowing the complete set of alignment attributes which apply to a
particular declaration.

llvm-svn: 175861

3 files changed, 105 insertions, 0 deletions

diff --git a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p6.cpp b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p6.cpp
new file mode 100644
index 00000000000..8cf5b266bb2
--- /dev/null
+++ b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p6.cpp
@@ -0,0 +1,83 @@
+// RUN: %clang_cc1 -std=c++11 -verify %s
+
+alignas(4) extern int n1; // expected-note {{previous declaration}}
+alignas(8) int n1; // expected-error {{redeclaration has different alignment requirement (8 vs 4)}}
+
+alignas(8) int n2; // expected-note {{previous declaration}}
+alignas(4) extern int n2; // expected-error {{different alignment requirement (4 vs 8)}}
+
+alignas(8) extern int n3; // expected-note {{previous declaration}}
+alignas(4) extern int n3; // expected-error {{different alignment requirement (4 vs 8)}}
+
+extern int n4;
+alignas(8) extern int n4;
+
+alignas(8) extern int n5;
+extern int n5;
+
+int n6; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
+alignas(8) extern int n6; // expected-note {{declared with 'alignas' attribute here}}
+
+extern int n7;
+alignas(8) int n7;
+
+alignas(8) extern int n8; // expected-note {{declared with 'alignas' attribute here}}
+int n8; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
+
+int n9; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
+alignas(4) extern int n9; // expected-note {{declared with 'alignas' attribute here}}
+
+
+enum alignas(2) E : char; // expected-note {{declared with 'alignas' attribute here}}
+enum E : char {}; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
+
+enum alignas(4) F : char; // expected-note {{previous declaration is here}}
+enum alignas(2) F : char; // expected-error {{redeclaration has different alignment requirement (2 vs 4)}}
+
+enum G : char;
+enum alignas(8) G : char {};
+enum G : char;
+
+enum H : char {}; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
+enum alignas(1) H : char; // expected-note {{declared with 'alignas' attribute here}}
+
+
+struct S;
+struct alignas(16) S; // expected-note {{declared with 'alignas' attribute here}}
+struct S;
+struct S { int n; }; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
+
+struct alignas(2) T;
+struct alignas(2) T { char c; }; // expected-note {{previous declaration is here}}
+struct T;
+struct alignas(4) T; // expected-error {{redeclaration has different alignment requirement (4 vs 2)}}
+
+struct U;
+struct alignas(2) U {};
+
+struct V {}; // expected-error {{'alignas' must be specified on definition if it is specified on any declaration}}
+struct alignas(1) V; // expected-note {{declared with 'alignas' attribute here}}
+
+template<int M, int N> struct alignas(M) W;
+template<int M, int N> struct alignas(N) W {};
+W<4,4> w44; // ok
+// FIXME: We should reject this.
+W<1,2> w12;
+static_assert(alignof(W<4,4>) == 4, "");
+
+template<int M, int N, int O, int P> struct X {
+  alignas(M) alignas(N) static char Buffer[32]; // expected-note {{previous declaration is here}}
+};
+template<int M, int N, int O, int P>
+alignas(O) alignas(P) char X<M, N, O, P>::Buffer[32]; // expected-error {{redeclaration has different alignment requirement (8 vs 2)}}
+char *x1848 = X<1,8,4,8>::Buffer; // ok
+char *x1248 = X<1,2,4,8>::Buffer; // expected-note {{in instantiation of}}
+
+template<int M, int N, int O, int P> struct Y {
+  enum alignas(M) alignas(N) E : char;
+};
+template<int M, int N, int O, int P>
+enum alignas(O) alignas(P) Y<M,N,O,P>::E : char { e };
+int y1848 = Y<1,8,4,8>::e;
+// FIXME: We should reject this.
+int y1248 = Y<1,2,4,8>::e;
diff --git a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p7.cpp b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p7.cpp
new file mode 100644
index 00000000000..93b1c6461a4
--- /dev/null
+++ b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p7.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -std=c++11 -verify %s
+
+template<typename T, typename A, int N> struct X {
+  alignas(T) alignas(A) T buffer[N];
+};
+
+static_assert(alignof(X<char, int, sizeof(int)>) == alignof(int), "");
+static_assert(alignof(X<int, char, 1>) == alignof(int), "");
+
+
+template<typename T, typename A, int N> struct Y {
+  alignas(A) T buffer[N]; // expected-error {{requested alignment is less than minimum alignment of 4 for type 'int [1]'}}
+};
+
+static_assert(alignof(Y<char, int, sizeof(int)>) == alignof(int), "");
+static_assert(alignof(Y<int, char, 1>) == alignof(int), ""); // expected-note {{in instantiation of}}
diff --git a/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p8.cpp b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p8.cpp
new file mode 100644
index 00000000000..686aac2802a
--- /dev/null
+++ b/clang/test/CXX/dcl.dcl/dcl.attr/dcl.align/p8.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -std=c++11 -verify %s
+
+alignas(double) void f(); // expected-error {{'alignas' attribute only applies to variables, data members and tag types}}
+alignas(double) unsigned char c[sizeof(double)]; // expected-note {{previous}}
+extern unsigned char c[sizeof(double)];
+alignas(float) extern unsigned char c[sizeof(double)]; // expected-error {{different alignment}}