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translate-c: Fix casting of function pointers

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The @ptrCast(X, @alignCast(@alignOf(T), Y)) pattern is only correct if T
is not a function type or a pointer, in that case the @alignOf refers to
the pointer itself and not to the pointee type.
This commit is contained in:
LemonBoy
2021-04-25 16:50:41 +02:00
parent 19cec0db1e
commit ae15022406
3 changed files with 21 additions and 11 deletions
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2
src/translate_c.zig
View File

@@ -3539,7 +3539,7 @@ fn transCPtrCast(
expr
else blk: {
const child_type_node = try transQualType(c, scope, child_type, loc);
const alignof = try Tag.alignof.create(c.arena, child_type_node);
const alignof = try Tag.std_meta_alignment.create(c.arena, child_type_node);
const align_cast = try Tag.align_cast.create(c.arena, .{ .lhs = alignof, .rhs = expr });
break :blk align_cast;
};

12
src/translate_c/ast.zig
View File

@@ -120,8 +120,11 @@ pub const Node = extern union {
std_math_Log2Int,
/// @intCast(lhs, rhs)
int_cast,
/// @rem(lhs, rhs)
/// @import("std").meta.promoteIntLiteral(value, type, radix)
std_meta_promoteIntLiteral,
/// @import("std").meta.alignment(value)
std_meta_alignment,
/// @rem(lhs, rhs)
rem,
/// @divTrunc(lhs, rhs)
div_trunc,
@@ -260,6 +263,7 @@ pub const Node = extern union {
.switch_else,
.block_single,
.std_meta_sizeof,
.std_meta_alignment,
.bool_to_int,
.sizeof,
.alignof,
@@ -876,6 +880,11 @@ fn renderNode(c: *Context, node: Node) Allocator.Error!NodeIndex {
const import_node = try renderStdImport(c, "meta", "promoteIntLiteral");
return renderCall(c, import_node, &.{ payload.type, payload.value, payload.radix });
},
.std_meta_alignment => {
const payload = node.castTag(.std_meta_alignment).?.data;
const import_node = try renderStdImport(c, "meta", "alignment");
return renderCall(c, import_node, &.{payload});
},
.std_meta_sizeof => {
const payload = node.castTag(.std_meta_sizeof).?.data;
const import_node = try renderStdImport(c, "meta", "sizeof");
@@ -2144,6 +2153,7 @@ fn renderNodeGrouped(c: *Context, node: Node) !NodeIndex {
.typeof,
.typeinfo,
.std_meta_sizeof,
.std_meta_alignment,
.std_meta_cast,
.std_meta_promoteIntLiteral,
.std_meta_vector,

18
test/translate_c.zig
View File

@@ -1363,7 +1363,7 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
, &[_][]const u8{
\\pub export fn ptrcast() [*c]f32 {
\\ var a: [*c]c_int = undefined;
\\ return @ptrCast([*c]f32, @alignCast(@alignOf(f32), a));
\\ return @ptrCast([*c]f32, @alignCast(@import("std").meta.alignment(f32), a));
\\}
});
@@ -1387,16 +1387,16 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
\\pub export fn test_ptr_cast() void {
\\ var p: ?*c_void = undefined;
\\ {
\\ var to_char: [*c]u8 = @ptrCast([*c]u8, @alignCast(@alignOf(u8), p));
\\ var to_short: [*c]c_short = @ptrCast([*c]c_short, @alignCast(@alignOf(c_short), p));
\\ var to_int: [*c]c_int = @ptrCast([*c]c_int, @alignCast(@alignOf(c_int), p));
\\ var to_longlong: [*c]c_longlong = @ptrCast([*c]c_longlong, @alignCast(@alignOf(c_longlong), p));
\\ var to_char: [*c]u8 = @ptrCast([*c]u8, @alignCast(@import("std").meta.alignment(u8), p));
\\ var to_short: [*c]c_short = @ptrCast([*c]c_short, @alignCast(@import("std").meta.alignment(c_short), p));
\\ var to_int: [*c]c_int = @ptrCast([*c]c_int, @alignCast(@import("std").meta.alignment(c_int), p));
\\ var to_longlong: [*c]c_longlong = @ptrCast([*c]c_longlong, @alignCast(@import("std").meta.alignment(c_longlong), p));
\\ }
\\ {
\\ var to_char: [*c]u8 = @ptrCast([*c]u8, @alignCast(@alignOf(u8), p));
\\ var to_short: [*c]c_short = @ptrCast([*c]c_short, @alignCast(@alignOf(c_short), p));
\\ var to_int: [*c]c_int = @ptrCast([*c]c_int, @alignCast(@alignOf(c_int), p));
\\ var to_longlong: [*c]c_longlong = @ptrCast([*c]c_longlong, @alignCast(@alignOf(c_longlong), p));
\\ var to_char: [*c]u8 = @ptrCast([*c]u8, @alignCast(@import("std").meta.alignment(u8), p));
\\ var to_short: [*c]c_short = @ptrCast([*c]c_short, @alignCast(@import("std").meta.alignment(c_short), p));
\\ var to_int: [*c]c_int = @ptrCast([*c]c_int, @alignCast(@import("std").meta.alignment(c_int), p));
\\ var to_longlong: [*c]c_longlong = @ptrCast([*c]c_longlong, @alignCast(@import("std").meta.alignment(c_longlong), p));
\\ }
\\}
});