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translate-c: fix function prototype decalared inside a function

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* If a function prototype is declarated inside a function, do not
  translate it to a top-level extern function declaration. Similar to
  extern local variable, just wrapped it into a block-local struct.

* Add a new extern_local_fn tag of aro_translate_c node for present
  extern local function declaration.

* When a function body has a C function prototype declaration, it adds
  an extern local function declaration. Subsequent function references
  will look for this function declaration.
This commit is contained in:
Parker Liu 2025-04-03 04:07:41 +08:00 committed by Alex Rønne Petersen
parent 0b4176891c
commit 06fc600aec
No known key found for this signature in database
4 changed files with 78 additions and 20 deletions
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24
lib/compiler/aro_translate_c.zig
View File

@ -1502,19 +1502,29 @@ pub fn ScopeExtra(comptime ScopeExtraContext: type, comptime ScopeExtraType: typ
return scope.base.parent.?.getAlias(name);
}
/// Finds the (potentially) mangled struct name for a locally scoped extern variable given the original declaration name.
/// Finds the (potentially) mangled struct name for a locally scoped extern variable or function given the original declaration name.
///
/// Block scoped extern declarations translate to:
/// const MangledStructName = struct {extern [qualifiers] original_extern_variable_name: [type]};
/// This finds MangledStructName given original_extern_variable_name for referencing correctly in transDeclRefExpr()
pub fn getLocalExternAlias(scope: *Block, name: []const u8) ?[]const u8 {
for (scope.statements.items) |node| {
if (node.tag() == .extern_local_var) {
const parent_node = node.castTag(.extern_local_var).?;
const init_node = parent_node.data.init.castTag(.var_decl).?;
if (std.mem.eql(u8, init_node.data.name, name)) {
return parent_node.data.name;
}
switch (node.tag()) {
.extern_local_var => {
const parent_node = node.castTag(.extern_local_var).?;
const init_node = parent_node.data.init.castTag(.var_decl).?;
if (std.mem.eql(u8, init_node.data.name, name)) {
return parent_node.data.name;
}
},
.extern_local_fn => {
const parent_node = node.castTag(.extern_local_fn).?;
const init_node = parent_node.data.init.castTag(.func).?;
if (std.mem.eql(u8, init_node.data.name.?, name)) {
return parent_node.data.name;
}
},
else => {},
}
}
return null;

20
lib/compiler/aro_translate_c/ast.zig
View File

@ -57,6 +57,8 @@ pub const Node = extern union {
static_local_var,
/// const ExternLocal_name = struct { init }
extern_local_var,
/// const ExternLocal_name = struct { init }
extern_local_fn,
/// var name = init.*
mut_str,
func,
@ -367,7 +369,13 @@ pub const Node = extern union {
.c_pointer, .single_pointer => Payload.Pointer,
.array_type, .null_sentinel_array_type => Payload.Array,
.arg_redecl, .alias, .fail_decl => Payload.ArgRedecl,
.var_simple, .pub_var_simple, .static_local_var, .extern_local_var, .mut_str => Payload.SimpleVarDecl,
.var_simple,
.pub_var_simple,
.static_local_var,
.extern_local_var,
.extern_local_fn,
.mut_str,
=> Payload.SimpleVarDecl,
.enum_constant => Payload.EnumConstant,
.array_filler => Payload.ArrayFiller,
.pub_inline_fn => Payload.PubInlineFn,
@ -1285,8 +1293,11 @@ fn renderNode(c: *Context, node: Node) Allocator.Error!NodeIndex {
},
});
},
.extern_local_var => {
const payload = node.castTag(.extern_local_var).?.data;
.extern_local_var, .extern_local_fn => {
const payload = if (node.tag() == .extern_local_var)
node.castTag(.extern_local_var).?.data
else
node.castTag(.extern_local_fn).?.data;
const const_tok = try c.addToken(.keyword_const, "const");
_ = try c.addIdentifier(payload.name);
@ -2338,7 +2349,7 @@ fn renderNullSentinelArrayType(c: *Context, len: usize, elem_type: Node) !NodeIn
fn addSemicolonIfNeeded(c: *Context, node: Node) !void {
switch (node.tag()) {
.warning => unreachable,
.var_decl, .var_simple, .arg_redecl, .alias, .block, .empty_block, .block_single, .@"switch", .static_local_var, .extern_local_var, .mut_str => {},
.var_decl, .var_simple, .arg_redecl, .alias, .block, .empty_block, .block_single, .@"switch", .static_local_var, .extern_local_var, .extern_local_fn, .mut_str => {},
.while_true => {
const payload = node.castTag(.while_true).?.data;
return addSemicolonIfNotBlock(c, payload);
@ -2435,6 +2446,7 @@ fn renderNodeGrouped(c: *Context, node: Node) !NodeIndex {
.builtin_extern,
.static_local_var,
.extern_local_var,
.extern_local_fn,
.mut_str,
.macro_arithmetic,
=> {

47
src/translate_c.zig
View File

@ -325,7 +325,7 @@ fn declVisitorNamesOnly(c: *Context, decl: *const clang.Decl) Error!void {
fn declVisitor(c: *Context, decl: *const clang.Decl) Error!void {
switch (decl.getKind()) {
.Function => {
return visitFnDecl(c, @as(*const clang.FunctionDecl, @ptrCast(decl)));
return transFnDecl(c, &c.global_scope.base, @as(*const clang.FunctionDecl, @ptrCast(decl)));
},
.Typedef => {
try transTypeDef(c, &c.global_scope.base, @as(*const clang.TypedefNameDecl, @ptrCast(decl)));
@ -367,7 +367,7 @@ fn transFileScopeAsm(c: *Context, scope: *Scope, file_scope_asm: *const clang.Fi
try scope.appendNode(comptime_node);
}
fn visitFnDecl(c: *Context, fn_decl: *const clang.FunctionDecl) Error!void {
fn transFnDecl(c: *Context, scope: *Scope, fn_decl: *const clang.FunctionDecl) Error!void {
const fn_name = try c.str(@as(*const clang.NamedDecl, @ptrCast(fn_decl)).getName_bytes_begin());
if (c.global_scope.sym_table.contains(fn_name))
return; // Avoid processing this decl twice
@ -375,7 +375,7 @@ fn visitFnDecl(c: *Context, fn_decl: *const clang.FunctionDecl) Error!void {
// Skip this declaration if a proper definition exists
if (!fn_decl.isThisDeclarationADefinition()) {
if (fn_decl.getDefinition()) |def|
return visitFnDecl(c, def);
return transFnDecl(c, scope, def);
}
const fn_decl_loc = fn_decl.getLocation();
@ -446,6 +446,9 @@ fn visitFnDecl(c: *Context, fn_decl: *const clang.FunctionDecl) Error!void {
};
if (!decl_ctx.has_body) {
if (scope.id != .root) {
return addLocalExternFnDecl(c, scope, fn_name, Node.initPayload(&proto_node.base));
}
return addTopLevelDecl(c, fn_name, Node.initPayload(&proto_node.base));
}
@ -455,7 +458,7 @@ fn visitFnDecl(c: *Context, fn_decl: *const clang.FunctionDecl) Error!void {
block_scope.return_type = return_qt;
defer block_scope.deinit();
const scope = &block_scope.base;
const top_scope = &block_scope.base;
var param_id: c_uint = 0;
for (proto_node.data.params) |*param| {
@ -508,7 +511,7 @@ fn visitFnDecl(c: *Context, fn_decl: *const clang.FunctionDecl) Error!void {
break :blk;
}
const rhs = transZeroInitExpr(c, scope, fn_decl_loc, return_qt.getTypePtr()) catch |err| switch (err) {
const rhs = transZeroInitExpr(c, top_scope, fn_decl_loc, return_qt.getTypePtr()) catch |err| switch (err) {
error.OutOfMemory => |e| return e,
error.UnsupportedTranslation,
error.UnsupportedType,
@ -1874,7 +1877,7 @@ fn transDeclStmtOne(
try transEnumDecl(c, scope, @as(*const clang.EnumDecl, @ptrCast(decl)));
},
.Function => {
try visitFnDecl(c, @as(*const clang.FunctionDecl, @ptrCast(decl)));
try transFnDecl(c, scope, @as(*const clang.FunctionDecl, @ptrCast(decl)));
},
else => {
const decl_name = try c.str(decl.getDeclKindName());
@ -1903,11 +1906,19 @@ fn transDeclRefExpr(
const name = try c.str(@as(*const clang.NamedDecl, @ptrCast(value_decl)).getName_bytes_begin());
const mangled_name = scope.getAlias(name);
const decl_is_var = @as(*const clang.Decl, @ptrCast(value_decl)).getKind() == .Var;
const potential_local_extern = if (decl_is_var) ((@as(*const clang.VarDecl, @ptrCast(value_decl)).getStorageClass() == .Extern) and (scope.id != .root)) else false;
const storage_class = @as(*const clang.VarDecl, @ptrCast(value_decl)).getStorageClass();
const potential_local_extern = if (decl_is_var) ((storage_class == .Extern) and (scope.id != .root)) else false;
var confirmed_local_extern = false;
var confirmed_local_extern_fn = false;
var ref_expr = val: {
if (cIsFunctionDeclRef(@as(*const clang.Expr, @ptrCast(expr)))) {
if (scope.id != .root) {
if (scope.getLocalExternAlias(name)) |v| {
confirmed_local_extern_fn = true;
break :val try Tag.identifier.create(c.arena, v);
}
}
break :val try Tag.fn_identifier.create(c.arena, mangled_name);
} else if (potential_local_extern) {
if (scope.getLocalExternAlias(name)) |v| {
@ -1934,6 +1945,11 @@ fn transDeclRefExpr(
.field_name = name, // by necessity, name will always == mangled_name
});
}
} else if (confirmed_local_extern_fn) {
ref_expr = try Tag.field_access.create(c.arena, .{
.lhs = ref_expr,
.field_name = name, // by necessity, name will always == mangled_name
});
}
scope.skipVariableDiscard(mangled_name);
return ref_expr;
@ -4213,6 +4229,23 @@ fn addTopLevelDecl(c: *Context, name: []const u8, decl_node: Node) !void {
}
}
/// Add an "extern" function prototype declaration that's been declared within a scoped block.
/// Similar to static local variables, this will be wrapped in a struct to work with Zig's syntax requirements.
///
fn addLocalExternFnDecl(c: *Context, scope: *Scope, name: []const u8, decl_node: Node) !void {
const bs: *Scope.Block = try scope.findBlockScope(c);
// Special naming convention for local extern function wrapper struct,
// this named "ExternLocal_[name]".
const struct_name = try std.fmt.allocPrint(c.arena, "{s}_{s}", .{ Scope.Block.extern_inner_prepend, name });
// Outer Node for the wrapper struct
const node = try Tag.extern_local_fn.create(c.arena, .{ .name = struct_name, .init = decl_node });
try bs.statements.append(node);
try bs.discardVariable(c, struct_name);
}
fn transQualTypeInitializedStringLiteral(c: *Context, elem_ty: Node, string_lit: *const clang.StringLiteral) TypeError!Node {
const string_lit_size = string_lit.getLength();
const array_size = @as(usize, @intCast(string_lit_size));

7
test/translate_c.zig
View File

@ -3537,9 +3537,12 @@ pub fn addCases(cases: *tests.TranslateCContext) void {
\\ return bar(1, 2);
\\}
, &[_][]const u8{
\\pub extern fn bar(c_int, c_int) c_int;
\\pub export fn foo() c_int {
\\ return bar(@as(c_int, 1), @as(c_int, 2));
\\ const ExternLocal_bar = struct {
\\ pub extern fn bar(c_int, c_int) c_int;
\\ };
\\ _ = &ExternLocal_bar;
\\ return ExternLocal_bar.bar(@as(c_int, 1), @as(c_int, 2));
\\}
});