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Make translate-c more robust in handling macro functions.

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Translate-c didn't properly account for C macro functions having parameter names that are C keywords. So something like `#define FOO(float) ((float) + 10)` would've been interpreted as casting `+10` to a `float` type, instead of adding `10` to the parameter `float`.

An example of a real-world macro function like this is SDL3's `SDL_DEFINE_AUDIO_FORMAT` from `SDL_audio.h`, which uses `signed` as a parameter.
This commit is contained in:
Matthew Roush 2025-04-07 16:53:38 -04:00 committed by GitHub
parent f2f36c49c8
commit fb1d4990cb
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GPG Key ID: B5690EEEBB952194
2 changed files with 179 additions and 68 deletions
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69
src/translate_c.zig
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@ -5226,6 +5226,7 @@ const MacroCtx = struct {
loc: clang.SourceLocation,
name: []const u8,
refs_var_decl: bool = false,
fn_params: ?[]const ast.Payload.Param = null,
fn peek(self: *MacroCtx) ?CToken.Id {
if (self.i >= self.list.len) return null;
@ -5298,6 +5299,15 @@ const MacroCtx = struct {
}
return null;
}
fn checkFnParam(self: *MacroCtx, str: []const u8) bool {
if (self.fn_params == null) return false;
for (self.fn_params.?) |param| {
if (mem.eql(u8, param.name.?, str)) return true;
}
return false;
}
};
fn getMacroText(unit: *const clang.ASTUnit, c: *const Context, macro: *const clang.MacroDefinitionRecord) ![]const u8 {
@ -5474,10 +5484,9 @@ fn transMacroFnDefine(c: *Context, m: *MacroCtx) ParseError!void {
defer fn_params.deinit();
while (true) {
switch (m.peek().?) {
.identifier, .extended_identifier => _ = m.next(),
else => break,
}
if (!m.peek().?.isMacroIdentifier()) break;
_ = m.next();
const mangled_name = try block_scope.makeMangledName(c, m.slice());
try fn_params.append(.{
@ -5490,6 +5499,8 @@ fn transMacroFnDefine(c: *Context, m: *MacroCtx) ParseError!void {
_ = m.next();
}
m.fn_params = fn_params.items;
try m.skip(c, .r_paren);
if (m.checkTranslatableMacro(scope, fn_params.items)) |err| switch (err) {
@ -5905,7 +5916,18 @@ fn parseCPrimaryExpr(c: *Context, m: *MacroCtx, scope: *Scope) ParseError!Node {
.pp_num => {
return parseCNumLit(c, m);
},
.identifier, .extended_identifier => {
.l_paren => {
const inner_node = try parseCExpr(c, m, scope);
try m.skip(c, .r_paren);
return inner_node;
},
else => {},
}
// The C preprocessor has no knowledge of C, so C keywords aren't special in macros.
// Thus the current token should be treated like an identifier if its name matches a parameter.
if (tok == .identifier or tok == .extended_identifier or m.checkFnParam(slice)) {
if (c.global_scope.blank_macros.contains(slice)) {
return parseCPrimaryExpr(c, m, scope);
}
@ -5919,14 +5941,8 @@ fn parseCPrimaryExpr(c: *Context, m: *MacroCtx, scope: *Scope) ParseError!Node {
if (!var_decl_node.data.is_const) m.refs_var_decl = true;
}
return identifier;
},
.l_paren => {
const inner_node = try parseCExpr(c, m, scope);
}
try m.skip(c, .r_paren);
return inner_node;
},
else => {
// for handling type macros (EVIL)
// TODO maybe detect and treat type macros as typedefs in parseCSpecifierQualifierList?
m.i -= 1;
@ -5935,8 +5951,6 @@ fn parseCPrimaryExpr(c: *Context, m: *MacroCtx, scope: *Scope) ParseError!Node {
}
try m.fail(c, "unable to translate C expr: unexpected token '{s}'", .{tok.symbol()});
return error.ParseError;
},
}
}
fn macroIntFromBool(c: *Context, node: Node) !Node {
@ -6199,12 +6213,14 @@ fn parseCTypeName(c: *Context, m: *MacroCtx, scope: *Scope, allow_fail: bool) Pa
fn parseCSpecifierQualifierList(c: *Context, m: *MacroCtx, scope: *Scope, allow_fail: bool) ParseError!?Node {
const tok = m.next().?;
const slice = m.slice();
const mangled_name = scope.getAlias(slice);
if (!m.checkFnParam(mangled_name)) {
switch (tok) {
.identifier, .extended_identifier => {
if (c.global_scope.blank_macros.contains(m.slice())) {
return try parseCSpecifierQualifierList(c, m, scope, allow_fail);
}
const mangled_name = scope.getAlias(m.slice());
if (!allow_fail or c.typedefs.contains(mangled_name)) {
if (builtin_typedef_map.get(mangled_name)) |ty| return try Tag.type.create(c.arena, ty);
return try Tag.identifier.create(c.arena, mangled_name);
@ -6227,7 +6243,6 @@ fn parseCSpecifierQualifierList(c: *Context, m: *MacroCtx, scope: *Scope, allow_
},
.keyword_enum, .keyword_struct, .keyword_union => {
// struct Foo will be declared as struct_Foo by transRecordDecl
const slice = m.slice();
try m.skip(c, .identifier);
const name = try std.fmt.allocPrint(c.arena, "{s}_{s}", .{ slice, m.slice() });
@ -6235,6 +6250,14 @@ fn parseCSpecifierQualifierList(c: *Context, m: *MacroCtx, scope: *Scope, allow_
},
else => {},
}
} else {
if (allow_fail) {
m.i -= 1;
return null;
} else {
return try Tag.identifier.create(c.arena, mangled_name);
}
}
if (allow_fail) {
m.i -= 1;
@ -6511,7 +6534,7 @@ fn parseCPostfixExprInner(c: *Context, m: *MacroCtx, scope: *Scope, type_name: ?
}
fn parseCUnaryExpr(c: *Context, m: *MacroCtx, scope: *Scope) ParseError!Node {
switch (m.next().?) {
sw: switch (m.next().?) {
.bang => {
const operand = try macroIntToBool(c, try parseCCastExpr(c, m, scope));
return Tag.not.create(c.arena, operand);
@ -6534,6 +6557,9 @@ fn parseCUnaryExpr(c: *Context, m: *MacroCtx, scope: *Scope) ParseError!Node {
return Tag.address_of.create(c.arena, operand);
},
.keyword_sizeof => {
// 'sizeof' could be used as a parameter to a macro function.
if (m.checkFnParam(m.slice())) break :sw;
const operand = if (m.peek().? == .l_paren) blk: {
_ = m.next();
const inner = (try parseCTypeName(c, m, scope, false)).?;
@ -6544,6 +6570,9 @@ fn parseCUnaryExpr(c: *Context, m: *MacroCtx, scope: *Scope) ParseError!Node {
return Tag.helpers_sizeof.create(c.arena, operand);
},
.keyword_alignof => {
// 'alignof' could be used as a parameter to a macro function.
if (m.checkFnParam(m.slice())) break :sw;
// TODO this won't work if using <stdalign.h>'s
// #define alignof _Alignof
try m.skip(c, .l_paren);
@ -6556,11 +6585,11 @@ fn parseCUnaryExpr(c: *Context, m: *MacroCtx, scope: *Scope) ParseError!Node {
try m.fail(c, "TODO unary inc/dec expr", .{});
return error.ParseError;
},
else => {
else => {},
}
m.i -= 1;
return try parseCPostfixExpr(c, m, scope, null);
},
}
}
fn getContainer(c: *Context, node: Node) ?Node {

82
test/cases/translate_c/c_keywords_as_macro_function_parameters.c Normal file
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@ -0,0 +1,82 @@
#define GUARDED_INT_ADDITION(int) ((int) + 1)
#define UNGUARDED_INT_SUBTRACTION(int) (int - 2)
#define GUARDED_INT_MULTIPLY(int) ((int) * 3)
#define UNGUARDED_INT_DIVIDE(int) (int / 4)
#define WRAPPED_RETURN(return) ((return) % 2)
#define UNWRAPPED_RETURN(return) (return ^ 0x7F)
#define WITH_TWO_PARAMETERS(signed, x) ((signed) + (x) + 9)
#define GUARDED_ALIGNOF(_Alignof) ((_Alignof) & 0x55)
#define UNGUARDED_ALIGNOF(_Alignof) (_Alignof | 0x80)
#define GUARDED_SIZEOF(sizeof) ((sizeof) == 64)
#define UNGUARDED_SIZEOF(sizeof) (sizeof < 64)
#define SIZEOF(x) ((int)sizeof(x))
#define SIZEOF2(x) ((int)sizeof x)
// translate-c
// c_frontend=clang
//
// pub inline fn GUARDED_INT_ADDITION(int: anytype) @TypeOf(int + @as(c_int, 1)) {
// _ = &int;
// return int + @as(c_int, 1);
// }
// pub inline fn UNGUARDED_INT_SUBTRACTION(int: anytype) @TypeOf(int - @as(c_int, 2)) {
// _ = &int;
// return int - @as(c_int, 2);
// }
// pub inline fn GUARDED_INT_MULTIPLY(int: anytype) @TypeOf(int * @as(c_int, 3)) {
// _ = &int;
// return int * @as(c_int, 3);
// }
// pub inline fn UNGUARDED_INT_DIVIDE(int: anytype) @TypeOf(@import("std").zig.c_translation.MacroArithmetic.div(int, @as(c_int, 4))) {
// _ = &int;
// return @import("std").zig.c_translation.MacroArithmetic.div(int, @as(c_int, 4));
// }
// pub inline fn WRAPPED_RETURN(@"return": anytype) @TypeOf(@import("std").zig.c_translation.MacroArithmetic.rem(@"return", @as(c_int, 2))) {
// _ = &@"return";
// return @import("std").zig.c_translation.MacroArithmetic.rem(@"return", @as(c_int, 2));
// }
// pub inline fn UNWRAPPED_RETURN(@"return": anytype) @TypeOf(@"return" ^ @as(c_int, 0x7F)) {
// _ = &@"return";
// return @"return" ^ @as(c_int, 0x7F);
// }
// pub inline fn WITH_TWO_PARAMETERS(signed: anytype, x: anytype) @TypeOf((signed + x) + @as(c_int, 9)) {
// _ = &signed;
// _ = &x;
// return (signed + x) + @as(c_int, 9);
// }
// pub inline fn GUARDED_ALIGNOF(_Alignof: anytype) @TypeOf(_Alignof & @as(c_int, 0x55)) {
// _ = &_Alignof;
// return _Alignof & @as(c_int, 0x55);
// }
// pub inline fn UNGUARDED_ALIGNOF(_Alignof: anytype) @TypeOf(_Alignof | @as(c_int, 0x80)) {
// _ = &_Alignof;
// return _Alignof | @as(c_int, 0x80);
// }
// pub inline fn GUARDED_SIZEOF(sizeof: anytype) @TypeOf(sizeof == @as(c_int, 64)) {
// _ = &sizeof;
// return sizeof == @as(c_int, 64);
// }
// pub inline fn UNGUARDED_SIZEOF(sizeof: anytype) @TypeOf(sizeof < @as(c_int, 64)) {
// _ = &sizeof;
// return sizeof < @as(c_int, 64);
// }
// pub inline fn SIZEOF(x: anytype) c_int {
// _ = &x;
// return @import("std").zig.c_translation.cast(c_int, @import("std").zig.c_translation.sizeof(x));
// }
// pub inline fn SIZEOF2(x: anytype) c_int {
// _ = &x;
// return @import("std").zig.c_translation.cast(c_int, @import("std").zig.c_translation.sizeof(x));
// }