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translate-c: do not translate macros which use arguments as struct/union/enum names

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Consider this C macro:
```c
#define FOO(x) struct x
```

Previously, translate-c did not detect that the `x` in the body referred
to the argument, so wrongly translated this code as using the
nonexistent `struct_x`. Since undefined identifiers are noticed in
AstGen, this prevents the translated file from being usable at all.

translate-c now instead detects this case and emits an appropriate
compile error in the macro's place.
This commit is contained in:
mlugg 2023-09-16 22:38:47 +01:00
parent 28caaea093
commit 0fa8cf44f6
No known key found for this signature in database
GPG Key ID: 58978E823BDE3EF9
2 changed files with 32 additions and 6 deletions
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32
src/translate_c.zig
View File

@ -5524,22 +5524,38 @@ const MacroCtx = struct {
return MacroSlicer{ .source = self.source, .tokens = self.list };
}
fn containsUndefinedIdentifier(self: *MacroCtx, scope: *Scope, params: []const ast.Payload.Param) ?[]const u8 {
const MacroTranslateError = union(enum) {
undefined_identifier: []const u8,
invalid_arg_usage: []const u8,
};
fn checkTranslatableMacro(self: *MacroCtx, scope: *Scope, params: []const ast.Payload.Param) ?MacroTranslateError {
const slicer = self.makeSlicer();
var last_is_type_kw = false;
var i: usize = 1; // index 0 is the macro name
while (i < self.list.len) : (i += 1) {
const token = self.list[i];
switch (token.id) {
.Period, .Arrow => i += 1, // skip next token since field identifiers can be unknown
.Keyword_struct, .Keyword_union, .Keyword_enum => if (!last_is_type_kw) {
last_is_type_kw = true;
continue;
},
.Identifier => {
const identifier = slicer.slice(token);
const is_param = for (params) |param| {
if (param.name != null and mem.eql(u8, identifier, param.name.?)) break true;
} else false;
if (!scope.contains(identifier) and !isBuiltinDefined(identifier) and !is_param) return identifier;
if (is_param and last_is_type_kw) {
return .{ .invalid_arg_usage = identifier };
}
if (!scope.contains(identifier) and !isBuiltinDefined(identifier) and !is_param) {
return .{ .undefined_identifier = identifier };
}
},
else => {},
}
last_is_type_kw = false;
}
return null;
}
@ -5649,8 +5665,10 @@ fn transPreprocessorEntities(c: *Context, unit: *clang.ASTUnit) Error!void {
fn transMacroDefine(c: *Context, m: *MacroCtx) ParseError!void {
const scope = &c.global_scope.base;
if (m.containsUndefinedIdentifier(scope, &.{})) |ident|
return m.fail(c, "unable to translate macro: undefined identifier `{s}`", .{ident});
if (m.checkTranslatableMacro(scope, &.{})) |err| switch (err) {
.undefined_identifier => |ident| return m.fail(c, "unable to translate macro: undefined identifier `{s}`", .{ident}),
.invalid_arg_usage => unreachable, // no args
};
const init_node = try parseCExpr(c, m, scope);
const last = m.next().?;
@ -5698,8 +5716,10 @@ fn transMacroFnDefine(c: *Context, m: *MacroCtx) ParseError!void {
try m.skip(c, .RParen);
if (m.containsUndefinedIdentifier(scope, fn_params.items)) |ident|
return m.fail(c, "unable to translate macro: undefined identifier `{s}`", .{ident});
if (m.checkTranslatableMacro(scope, fn_params.items)) |err| switch (err) {
.undefined_identifier => |ident| return m.fail(c, "unable to translate macro: undefined identifier `{s}`", .{ident}),
.invalid_arg_usage => |ident| return m.fail(c, "unable to translate macro: untranslatable usage of arg `{s}`", .{ident}),
};
const expr = try parseCExpr(c, m, scope);
const last = m.next().?;

6
test/translate_c.zig
View File

@ -4129,4 +4129,10 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
\\ }) != 0) {}
\\}
});
cases.add("macro using argument as struct name is not translated",
\\#define FOO(x) struct x
, &[_][]const u8{
\\pub const FOO = @compileError("unable to translate macro: untranslatable usage of arg `x`");
});
}