Implement semantic analysis for the GNU flexible array initialization

extension. The interaction with designated initializers is a
bit... interesting... but we follow GNU's lead and don't permit too
much crazy code in this area.

Also, make the "excess initializers" error message a bit more
informative.

Addresses PR2561: http://llvm.org/bugs/show_bug.cgi?id=2561


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63785 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 44 insertions, 7 deletions

diff --git a/test/Sema/array-init.c b/test/Sema/array-init.c
index b10d60da3f..2c835bd54f 100644
--- a/test/Sema/array-init.c
+++ b/test/Sema/array-init.c
@@ -20,7 +20,7 @@ void func() {
 
   int x3[x] = { 1, 2 }; // expected-error{{variable-sized object may not be initialized}}
 
-  int x4 = { 1, 2 }; // expected-warning{{braces around scalar initializer}} expected-error{{excess elements in array initializer}}
+  int x4 = { 1, 2 }; // expected-warning{{braces around scalar initializer}} expected-error{{excess elements in scalar initializer}}
 
   int y[4][3] = { 
     { 1, 3, 5 },
@@ -53,7 +53,7 @@ void func() {
 
 void test() {
   int y1[3] = { 
-    { 1, 2, 3 } // expected-warning{{braces around scalar initializer}} expected-error{{excess elements in array initializer}}
+    { 1, 2, 3 } // expected-warning{{braces around scalar initializer}} expected-error{{excess elements in scalar initializer}}
   };
   int y3[4][3] = {  
     { 1, 3, 5 },
@@ -201,14 +201,13 @@ int bar (void) {
   return z.z; 
 } 
 struct s3 {void (*a)(void);} t5 = {autoStructTest};
-// FIXME: GCC extension; flexible array init. Once this is implemented, the warning should be removed.
 // Note that clang objc implementation depends on this extension.
-struct {int a; int b[];} t6 = {1, {1, 2, 3}}; //expected-error{{excess elements in array initializer}}
+struct {int a; int b[];} t6 = {1, {1, 2, 3}};
 union {char a; int b;} t7[] = {1, 2, 3};
 int t8[sizeof t7 == (3*sizeof(int)) ? 1 : -1];
 
 struct bittest{int : 31, a, :21, :12, b;};
-struct bittest bittestvar = {1, 2, 3, 4}; //expected-error{{excess elements in array initializer}}
+struct bittest bittestvar = {1, 2, 3, 4}; //expected-error{{excess elements in struct initializer}}
 
 // Not completely sure what should happen here...
 int u1 = {}; //expected-warning{{use of GNU empty initializer extension}} expected-error{{scalar initializer cannot be empty}}
@@ -243,7 +242,7 @@ struct soft_segment_descriptor gdt_segs[] = {
 };
 
 static void sppp_ipv6cp_up();
-const struct {} ipcp = { sppp_ipv6cp_up }; //expected-warning{{empty struct extension}} expected-error{{excess elements in array initializer}}
+const struct {} ipcp = { sppp_ipv6cp_up }; //expected-warning{{empty struct extension}} expected-error{{excess elements in struct initializer}}
 
 struct _Matrix { union { float m[4][4]; }; }; //expected-warning{{anonymous unions are a GNU extension in C}}
 typedef struct _Matrix Matrix;
diff --git a/test/Sema/flexible-array-init.c b/test/Sema/flexible-array-init.c
new file mode 100644
index 0000000000..9ef6eb3bc0
--- /dev/null
+++ b/test/Sema/flexible-array-init.c
@@ -0,0 +1,38 @@
+// RUN: clang -fsyntax-only -verify %s
+struct one {
+  int a;
+  int values[];
+} x = {5, {1, 2, 3}};
+
+struct one x2 = { 5, 1, 2, 3 }; // expected-error{{excess elements in struct initializer}}
+
+void test() {
+  struct one x3 = {5, {1, 2, 3}};
+}
+
+struct foo { 
+  int x; 
+  int y[]; // expected-note{{initialized flexible array member 'y' is here}}
+}; 
+struct bar { struct foo z; };
+     
+struct foo a = { 1, { 2, 3, 4 } };        // Valid.
+struct bar b = { { 1, { 2, 3, 4 } } };    // expected-error{{non-empty initialization of flexible array member inside subobject}}
+struct bar c = { { 1, { } } };            // Valid.
+struct foo d[1] = { { 1, { 2, 3, 4 } } };  // expected-error{{'struct foo' may not be used as an array element due to flexible array member}}
+
+struct foo desig_foo = { .y = {2, 3, 4} };
+struct bar desig_bar = { .z.y = { } };
+struct bar desig_bar2 = { .z.y = { 2, 3, 4} }; // expected-error{{non-empty initialization of flexible array member inside subobject}}
+struct foo design_foo2 = { .y = 2 }; // expected-error{{flexible array requires brace-enclosed initializer}}
+
+struct point {
+  int x, y;
+};
+
+struct polygon {
+  int numpoints;
+  struct point points[]; // expected-note{{initialized flexible array member 'points' is here}}
+};
+struct polygon poly = { 
+  .points[2] = { 1, 2} }; // expected-error{{designator into flexible array member subobject}}
diff --git a/test/SemaCXX/dcl_init_aggr.cpp b/test/SemaCXX/dcl_init_aggr.cpp
index e5015fab03..fbe7de1563 100644
--- a/test/SemaCXX/dcl_init_aggr.cpp
+++ b/test/SemaCXX/dcl_init_aggr.cpp
@@ -118,5 +118,5 @@ union u { int a; char* b; };
 u u1 = { 1 }; 
 u u2 = u1; 
 u u3 = 1; // expected-error{{cannot initialize 'u3' with an rvalue of type 'int'}}
-u u4 = { 0, "asdf" };  // expected-error{{excess elements in array initializer}}
+u u4 = { 0, "asdf" };  // expected-error{{excess elements in union initializer}}
 u u5 = { "asdf" }; // expected-error{{incompatible type initializing 'char const [5]', expected 'int'}}