Commit 7b5fb79b5b

Vexu <git@vexu.eu>
2020-03-07 16:36:17
Translate C: Put an alignCast in c style pointer casts to allow opaque types to cast properly in C macros
Translate C: add test case for aligning opaque types in pointer casts
1 parent b3aef49
Changed files (2)
src-self-hosted
test
src-self-hosted/translate_c.zig
@@ -5519,12 +5519,12 @@ fn parseCPrimaryExpr(c: *Context, it: *CTokenList.Iterator, source: []const u8,
                 return error.ParseError;
             }
 
-            //if (@typeInfo(@TypeOf(x)) == .Pointer)
-            //    @ptrCast(dest, x)
-            //else if (@typeInfo(@TypeOf(x)) == .Int and @typeInfo(dest) == .Pointer)
+            //(  if (@typeInfo(@TypeOf(x)) == .Pointer)
+            //    @ptrCast(dest, @alignCast(@alignOf(dest.Child), x))
+            //else if (@typeInfo(@TypeOf(x)) == .Integer and @typeInfo(dest) == .Pointer))
             //    @intToPtr(dest, x)
             //else
-            //    @as(dest, x)
+            //    @as(dest, x) )
 
             const lparen = try appendToken(c, .LParen, "(");
 
@@ -5546,9 +5546,30 @@ fn parseCPrimaryExpr(c: *Context, it: *CTokenList.Iterator, source: []const u8,
             if_1.condition = &cmp_1.base;
             _ = try appendToken(c, .RParen, ")");
 
+            const period_tok = try appendToken(c, .Period, ".");
+            const child_ident = try transCreateNodeIdentifier(c, "Child");
+            const inner_node_child = try c.a().create(ast.Node.InfixOp);
+            inner_node_child.* = .{
+                .op_token = period_tok,
+                .lhs = inner_node,
+                .op = .Period,
+                .rhs = child_ident,
+            };
+
+            const align_of = try transCreateNodeBuiltinFnCall(c, "@alignOf");
+            try align_of.params.push(&inner_node_child.base);
+            align_of.rparen_token = try appendToken(c, .RParen, ")");
+            // hack to get zig fmt to render a comma in builtin calls
+            _ = try appendToken(c, .Comma, ",");
+
+            const align_cast = try transCreateNodeBuiltinFnCall(c, "@alignCast");
+            try align_cast.params.push(&align_of.base);
+            try align_cast.params.push(node_to_cast);
+            align_cast.rparen_token = try appendToken(c, .RParen, ")");
+
             const ptr_cast = try transCreateNodeBuiltinFnCall(c, "@ptrCast");
             try ptr_cast.params.push(inner_node);
-            try ptr_cast.params.push(node_to_cast);
+            try ptr_cast.params.push(&align_cast.base);
             ptr_cast.rparen_token = try appendToken(c, .RParen, ")");
             if_1.body = &ptr_cast.base;
 
test/translate_c.zig
@@ -1458,7 +1458,7 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
     cases.add("macro pointer cast",
         \\#define NRF_GPIO ((NRF_GPIO_Type *) NRF_GPIO_BASE)
     , &[_][]const u8{
-        \\pub const NRF_GPIO = (if (@typeInfo(@TypeOf(NRF_GPIO_BASE)) == .Pointer) @ptrCast([*c]NRF_GPIO_Type, NRF_GPIO_BASE) else if (@typeInfo(@TypeOf(NRF_GPIO_BASE)) == .Int and @typeInfo([*c]NRF_GPIO_Type) == .Pointer) @intToPtr([*c]NRF_GPIO_Type, NRF_GPIO_BASE) else @as([*c]NRF_GPIO_Type, NRF_GPIO_BASE));
+        \\pub const NRF_GPIO = (if (@typeInfo(@TypeOf(NRF_GPIO_BASE)) == .Pointer) @ptrCast([*c]NRF_GPIO_Type, @alignCast(@alignOf([*c]NRF_GPIO_Type.Child), NRF_GPIO_BASE)) else if (@typeInfo(@TypeOf(NRF_GPIO_BASE)) == .Int and @typeInfo([*c]NRF_GPIO_Type) == .Pointer) @intToPtr([*c]NRF_GPIO_Type, NRF_GPIO_BASE) else @as([*c]NRF_GPIO_Type, NRF_GPIO_BASE));
     });
 
     cases.add("basic macro function",
@@ -2668,11 +2668,11 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
         \\#define FOO(bar) baz((void *)(baz))
         \\#define BAR (void*) a
     , &[_][]const u8{
-        \\pub inline fn FOO(bar: var) @TypeOf(baz((if (@typeInfo(@TypeOf(baz)) == .Pointer) @ptrCast(*c_void, baz) else if (@typeInfo(@TypeOf(baz)) == .Int and @typeInfo(*c_void) == .Pointer) @intToPtr(*c_void, baz) else @as(*c_void, baz)))) {
-        \\    return baz((if (@typeInfo(@TypeOf(baz)) == .Pointer) @ptrCast(*c_void, baz) else if (@typeInfo(@TypeOf(baz)) == .Int and @typeInfo(*c_void) == .Pointer) @intToPtr(*c_void, baz) else @as(*c_void, baz)));
+        \\pub inline fn FOO(bar: var) @TypeOf(baz((if (@typeInfo(@TypeOf(baz)) == .Pointer) @ptrCast(*c_void, @alignCast(@alignOf(*c_void.Child), baz)) else if (@typeInfo(@TypeOf(baz)) == .Int and @typeInfo(*c_void) == .Pointer) @intToPtr(*c_void, baz) else @as(*c_void, baz)))) {
+        \\    return baz((if (@typeInfo(@TypeOf(baz)) == .Pointer) @ptrCast(*c_void, @alignCast(@alignOf(*c_void.Child), baz)) else if (@typeInfo(@TypeOf(baz)) == .Int and @typeInfo(*c_void) == .Pointer) @intToPtr(*c_void, baz) else @as(*c_void, baz)));
         \\}
     ,
-        \\pub const BAR = (if (@typeInfo(@TypeOf(a)) == .Pointer) @ptrCast(*c_void, a) else if (@typeInfo(@TypeOf(a)) == .Int and @typeInfo(*c_void) == .Pointer) @intToPtr(*c_void, a) else @as(*c_void, a));
+        \\pub const BAR = (if (@typeInfo(@TypeOf(a)) == .Pointer) @ptrCast(*c_void, @alignCast(@alignOf(*c_void.Child), a)) else if (@typeInfo(@TypeOf(a)) == .Int and @typeInfo(*c_void) == .Pointer) @intToPtr(*c_void, a) else @as(*c_void, a));
     });
 
     cases.add("macro conditional operator",
@@ -2879,4 +2879,19 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
     , &[_][]const u8{
         \\pub const FOO = 0x61626364;
     });
+
+    cases.add("Make sure casts are grouped",
+        \\typedef struct
+        \\{
+        \\    int i;
+        \\}
+        \\*_XPrivDisplay;
+        \\typedef struct _XDisplay Display;
+        \\#define DefaultScreen(dpy) (((_XPrivDisplay)(dpy))->default_screen)
+        \\
+    , &[_][]const u8{
+        \\pub inline fn DefaultScreen(dpy: var) @TypeOf((if (@typeInfo(@TypeOf(dpy)) == .Pointer) @ptrCast(_XPrivDisplay, @alignCast(@alignOf(_XPrivDisplay.Child), dpy)) else if (@typeInfo(@TypeOf(dpy)) == .Int and @typeInfo(_XPrivDisplay) == .Pointer) @intToPtr(_XPrivDisplay, dpy) else @as(_XPrivDisplay, dpy)).*.default_screen) {
+        \\    return (if (@typeInfo(@TypeOf(dpy)) == .Pointer) @ptrCast(_XPrivDisplay, @alignCast(@alignOf(_XPrivDisplay.Child), dpy)) else if (@typeInfo(@TypeOf(dpy)) == .Int and @typeInfo(_XPrivDisplay) == .Pointer) @intToPtr(_XPrivDisplay, dpy) else @as(_XPrivDisplay, dpy)).*.default_screen;
+        \\}
+    });
 }