Commit d5bbd74871

Andrew Kelley <andrew@ziglang.org>
2019-02-15 02:04:13
allow C pointers to have alignment
clang/gcc support pointer alignment attribute: https://clang.llvm.org/docs/AttributeReference.html#align-value
master
1 parent cc7060d
Changed files (3)
src
ir.cpp
test
stage1
behavior
type_info.zig
compile_errors.zig
src/ir.cpp
@@ -5057,11 +5057,6 @@ static IrInstruction *ir_gen_pointer_type(IrBuilder *irb, Scope *scope, AstNode
 
     IrInstruction *align_value;
     if (align_expr != nullptr) {
-        if (ptr_len == PtrLenC) {
-            exec_add_error_node(irb->codegen, irb->exec, node,
-                buf_sprintf("[*c] pointers may not have align attribute"));
-            return irb->codegen->invalid_instruction;
-        }
         align_value = ir_gen_node(irb, align_expr, scope);
         if (align_value == irb->codegen->invalid_instruction)
             return align_value;
test/stage1/behavior/type_info.zig
@@ -67,12 +67,12 @@ test "type info: C pointer type info" {
 }
 
 fn testCPtr() void {
-    const ptr_info = @typeInfo([*c]const i8);
+    const ptr_info = @typeInfo([*c]align(4) const i8);
     expect(TypeId(ptr_info) == TypeId.Pointer);
     expect(ptr_info.Pointer.size == TypeInfo.Pointer.Size.C);
     expect(ptr_info.Pointer.is_const);
     expect(!ptr_info.Pointer.is_volatile);
-    expect(ptr_info.Pointer.alignment == 1);
+    expect(ptr_info.Pointer.alignment == 4);
     expect(ptr_info.Pointer.child == i8);
 }
test/compile_errors.zig
@@ -123,12 +123,8 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
         \\export fn a() void {
         \\    const T = [*c]Foo;
         \\}
-        \\export fn b() void {
-        \\    const T = [*c]align(4) u8;
-        \\}
     ,
         ".tmp_source.zig:3:15: error: C pointers cannot point to non-C-ABI-compatible type 'Foo'",
-        ".tmp_source.zig:6:15: error: [*c] pointers may not have align attribute",
     );
 
     cases.addTest(