Sema: only ABI sized packed structs are extern compatible

5 files changed, 42 insertions, 75 deletions

diff --git a/test/c_abi/cfuncs.c b/test/c_abi/cfuncs.c
index 391e87fc67..439de8bbae 100644
--- a/test/c_abi/cfuncs.c
+++ b/test/c_abi/cfuncs.c
@@ -86,24 +86,8 @@ struct MedStructMixed {
 void zig_med_struct_mixed(struct MedStructMixed);
 struct MedStructMixed zig_ret_med_struct_mixed();
 
-struct SmallPackedStruct {
-    uint8_t a: 2;
-    uint8_t b: 2;
-    uint8_t c: 2;
-    uint8_t d: 2;
-    uint8_t e: 1;
-};
-
-struct BigPackedStruct {
-    uint64_t a: 64;
-    uint64_t b: 64;
-    uint64_t c: 64;
-    uint64_t d: 64;
-    uint8_t e: 8;
-};
-
-//void zig_small_packed_struct(struct SmallPackedStruct); // #1481
-void zig_big_packed_struct(struct BigPackedStruct);
+void zig_small_packed_struct(uint8_t);
+void zig_big_packed_struct(__int128);
 
 struct SplitStructInts {
     uint64_t a;
@@ -176,13 +160,19 @@ void run_c_tests(void) {
     }
 
     {
-        struct BigPackedStruct s = {1, 2, 3, 4, 5};
+        __int128 s = 0;
+        s |= 1 << 0;
+        s |= (__int128)2 << 64;
         zig_big_packed_struct(s);
     }
 
     {
-        struct SmallPackedStruct s = {0, 1, 2, 3, 1};
-        //zig_small_packed_struct(s);
+        uint8_t s = 0;
+        s |= 0 << 0;
+        s |= 1 << 2;
+        s |= 2 << 4;
+        s |= 3 << 6;
+        zig_small_packed_struct(s);
     }
 
     {
@@ -378,42 +368,32 @@ void c_split_struct_mixed(struct SplitStructMixed x) {
     assert_or_panic(y.c == 1337.0f);
 }
 
-struct SmallPackedStruct c_ret_small_packed_struct() {
-    struct SmallPackedStruct s = {
-        .a = 0,
-        .b = 1,
-        .c = 2,
-        .d = 3,
-        .e = 1,
-    };
+uint8_t c_ret_small_packed_struct() {
+    uint8_t s = 0;
+    s |= 0 << 0;
+    s |= 1 << 2;
+    s |= 2 << 4;
+    s |= 3 << 6;
     return s;
 }
 
-void c_small_packed_struct(struct SmallPackedStruct x) {
-    assert_or_panic(x.a == 0);
-    assert_or_panic(x.a == 1);
-    assert_or_panic(x.a == 2);
-    assert_or_panic(x.a == 3);
-    assert_or_panic(x.e == 1);
+void c_small_packed_struct(uint8_t x) {
+    assert_or_panic(((x >> 0) & 0x3) == 0);
+    assert_or_panic(((x >> 2) & 0x3) == 1);
+    assert_or_panic(((x >> 4) & 0x3) == 2);
+    assert_or_panic(((x >> 6) & 0x3) == 3);
 }
 
-struct BigPackedStruct c_ret_big_packed_struct() {
-    struct BigPackedStruct s = {
-        .a = 1,
-        .b = 2,
-        .c = 3,
-        .d = 4,
-        .e = 5,
-    };
+__int128 c_ret_big_packed_struct() {
+    __int128 s = 0;
+    s |= 1 << 0;
+    s |= (__int128)2 << 64;
     return s;
 }
 
-void c_big_packed_struct(struct BigPackedStruct x) {
-    assert_or_panic(x.a == 1);
-    assert_or_panic(x.b == 2);
-    assert_or_panic(x.c == 3);
-    assert_or_panic(x.d == 4);
-    assert_or_panic(x.e == 5);
+void c_big_packed_struct(__int128 x) {
+    assert_or_panic(((x >> 0) & 0xFFFFFFFFFFFFFFFF) == 1);
+    assert_or_panic(((x >> 64) & 0xFFFFFFFFFFFFFFFF) == 2);
 }
 
 struct SplitStructMixed c_ret_split_struct_mixed() {
diff --git a/test/c_abi/main.zig b/test/c_abi/main.zig
index 145bbc384a..a34e4eda8f 100644
--- a/test/c_abi/main.zig
+++ b/test/c_abi/main.zig
@@ -263,37 +263,30 @@ const SmallPackedStruct = packed struct {
     b: u2,
     c: u2,
     d: u2,
-    e: bool,
 };
-const c_small_packed_struct: fn (SmallPackedStruct) callconv(.C) void = @compileError("TODO: #1481");
+extern fn c_small_packed_struct(SmallPackedStruct) void;
 extern fn c_ret_small_packed_struct() SmallPackedStruct;
 
-// waiting on #1481
-//export fn zig_small_packed_struct(x: SmallPackedStruct) void {
-//    expect(x.a == 0) catch @panic("test failure");
-//    expect(x.b == 1) catch @panic("test failure");
-//    expect(x.c == 2) catch @panic("test failure");
-//    expect(x.d == 3) catch @panic("test failure");
-//    expect(x.e) catch @panic("test failure");
-//}
+export fn zig_small_packed_struct(x: SmallPackedStruct) void {
+    expect(x.a == 0) catch @panic("test failure");
+    expect(x.b == 1) catch @panic("test failure");
+    expect(x.c == 2) catch @panic("test failure");
+    expect(x.d == 3) catch @panic("test failure");
+}
 
 test "C ABI small packed struct" {
-    var s = SmallPackedStruct{ .a = 0, .b = 1, .c = 2, .d = 3, .e = true };
-    _ = s; //c_small_packed_struct(s); // waiting on #1481
+    var s = SmallPackedStruct{ .a = 0, .b = 1, .c = 2, .d = 3 };
+    c_small_packed_struct(s);
     var s2 = c_ret_small_packed_struct();
     try expect(s2.a == 0);
     try expect(s2.b == 1);
     try expect(s2.c == 2);
     try expect(s2.d == 3);
-    try expect(s2.e);
 }
 
 const BigPackedStruct = packed struct {
     a: u64,
     b: u64,
-    c: u64,
-    d: u64,
-    e: u8,
 };
 extern fn c_big_packed_struct(BigPackedStruct) void;
 extern fn c_ret_big_packed_struct() BigPackedStruct;
@@ -301,20 +294,14 @@ extern fn c_ret_big_packed_struct() BigPackedStruct;
 export fn zig_big_packed_struct(x: BigPackedStruct) void {
     expect(x.a == 1) catch @panic("test failure");
     expect(x.b == 2) catch @panic("test failure");
-    expect(x.c == 3) catch @panic("test failure");
-    expect(x.d == 4) catch @panic("test failure");
-    expect(x.e == 5) catch @panic("test failure");
 }
 
 test "C ABI big packed struct" {
-    var s = BigPackedStruct{ .a = 1, .b = 2, .c = 3, .d = 4, .e = 5 };
+    var s = BigPackedStruct{ .a = 1, .b = 2 };
     c_big_packed_struct(s);
     var s2 = c_ret_big_packed_struct();
     try expect(s2.a == 1);
     try expect(s2.b == 2);
-    try expect(s2.c == 3);
-    try expect(s2.d == 4);
-    try expect(s2.e == 5);
 }
 
 const SplitStructInt = extern struct {
diff --git a/test/cases/compile_errors/C_pointer_pointing_to_non_C_ABI_compatible_type_or_has_align_attr.zig b/test/cases/compile_errors/C_pointer_pointing_to_non_C_ABI_compatible_type_or_has_align_attr.zig
index 1b9118aa64..1472c7d5ba 100644
--- a/test/cases/compile_errors/C_pointer_pointing_to_non_C_ABI_compatible_type_or_has_align_attr.zig
+++ b/test/cases/compile_errors/C_pointer_pointing_to_non_C_ABI_compatible_type_or_has_align_attr.zig
@@ -10,5 +10,5 @@ export fn a() void {
 // target=native
 //
 // :3:19: error: C pointers cannot point to non-C-ABI-compatible type 'tmp.Foo'
-// :3:19: note: only structs with packed or extern layout are extern compatible
+// :3:19: note: only extern structs and ABI sized packed structs are extern compatible
 // :1:13: note: struct declared here
diff --git a/test/cases/compile_errors/function_with_non-extern_non-packed_struct_parameter.zig b/test/cases/compile_errors/function_with_non-extern_non-packed_struct_parameter.zig
index 0007a2014e..55ee277641 100644
--- a/test/cases/compile_errors/function_with_non-extern_non-packed_struct_parameter.zig
+++ b/test/cases/compile_errors/function_with_non-extern_non-packed_struct_parameter.zig
@@ -10,5 +10,5 @@ export fn entry(foo: Foo) void { _ = foo; }
 // target=native
 //
 // :6:17: error: parameter of type 'tmp.Foo' not allowed in function with calling convention 'C'
-// :6:17: note: only structs with packed or extern layout are extern compatible
+// :6:17: note: only extern structs and ABI sized packed structs are extern compatible
 // :1:13: note: struct declared here
diff --git a/test/cases/compile_errors/function_with_non-extern_non-packed_union_parameter.zig b/test/cases/compile_errors/function_with_non-extern_non-packed_union_parameter.zig
index 001d235e18..f848392c90 100644
--- a/test/cases/compile_errors/function_with_non-extern_non-packed_union_parameter.zig
+++ b/test/cases/compile_errors/function_with_non-extern_non-packed_union_parameter.zig
@@ -10,5 +10,5 @@ export fn entry(foo: Foo) void { _ = foo; }
 // target=native
 //
 // :6:17: error: parameter of type 'tmp.Foo' not allowed in function with calling convention 'C'
-// :6:17: note: only unions with packed or extern layout are extern compatible
+// :6:17: note: only extern unions and ABI sized packed unions are extern compatible
 // :1:13: note: union declared here