Fix 2D array support for C backend

This updates the C backend to use proper array types.

In order to do that, this commit also:
 - fixes up elem_ptr and field_ptr handling
 - adds `renderTypecast` (renders in C typecast format, e.g. "int* [10]")
 - adds a bit special handling for undefined pointers, which is necessary
   to support slice/elem_ptr to undefined decls

1 files changed, 32 insertions, 0 deletions

diff --git a/test/behavior/basic.zig b/test/behavior/basic.zig
index 61c7de7a23..05c1f1cda3 100644
--- a/test/behavior/basic.zig
+++ b/test/behavior/basic.zig
@@ -436,6 +436,38 @@ test "array 2D const double ptr" {
     try testArray2DConstDoublePtr(&rect_2d_vertexes[0][0]);
 }
 
+test "array 2D const double ptr with offset" {
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
+
+    const rect_2d_vertexes = [_][2]f32{
+        [_]f32{ 3.0, 4.239 },
+        [_]f32{ 1.0, 2.0 },
+    };
+    try testArray2DConstDoublePtr(&rect_2d_vertexes[1][0]);
+}
+
+test "array 3D const double ptr with offset" {
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
+
+    const rect_3d_vertexes = [_][2][2]f32{
+        [_][2]f32{
+            [_]f32{ 3.0, 4.239 },
+            [_]f32{ 3.5, 7.2 },
+        },
+        [_][2]f32{
+            [_]f32{ 3.0, 4.239 },
+            [_]f32{ 1.0, 2.0 },
+        },
+    };
+    try testArray2DConstDoublePtr(&rect_3d_vertexes[1][1][0]);
+}
+
 fn testArray2DConstDoublePtr(ptr: *const f32) !void {
     const ptr2 = @ptrCast([*]const f32, ptr);
     try expect(ptr2[0] == 1.0);