translate _Static_asserts

Author: Vexu

src/Translator.zig

@@ -469,6 +469,7 @@ pub fn translate(
         context.decl_table.deinit(gpa);
         context.alias_list.deinit();
         context.global_names.deinit(gpa);
+        context.weak_global_names.deinit(gpa);
         context.opaque_demotes.deinit(gpa);
         context.unnamed_typedefs.deinit(gpa);
         context.typedefs.deinit(gpa);
@@ -610,7 +611,9 @@ fn transDecl(c: *Context, scope: *Scope, decl: NodeIndex) !void {
         => {
             try transVarDecl(c, decl);
         },
-        .static_assert => try warn(c, &c.global_scope.base, c.tokenIndex(decl) orelse 0, "ignoring _Static_assert declaration", .{}),
+        .static_assert => {
+            try transStaticAssert(c, &c.global_scope.base, decl);
+        },
         else => unreachable,
     }
 }
@@ -991,6 +994,40 @@ fn transEnumDecl(c: *Context, scope: *Scope, enum_decl: *const Type.Enum, field_
     }
 }
 
+fn transStaticAssert(c: *Context, scope: *Scope, static_assert_node: NodeIndex) Error!void {
+    const node_data = c.tree.nodes.items(.data)[@intFromEnum(static_assert_node)];
+
+    const condition = c.transExpr(node_data.bin.lhs, .used) catch |err| switch (err) {
+        error.UnsupportedTranslation, error.UnsupportedType => {
+            return try warn(c, &c.global_scope.base, c.tokenIndex(node_data.bin.lhs).?, "unable to translate _Static_assert condition", .{});
+        },
+        error.OutOfMemory => |e| return e,
+    };
+
+    // generate @compileError message that matches C compiler output
+    const diagnostic = if (node_data.bin.rhs != .none) str: {
+        // Aro guarantees this to be a string literal.
+        const str_val = c.tree.value_map.get(node_data.bin.rhs).?;
+        const str_ty = c.tree.nodes.items(.ty)[@intFromEnum(node_data.bin.rhs)];
+
+        const bytes = c.comp.interner.get(str_val.ref()).bytes;
+        var buf = std.ArrayList(u8).init(c.gpa);
+        defer buf.deinit();
+
+        try buf.appendSlice("\"static assertion failed \\");
+
+        try buf.ensureUnusedCapacity(bytes.len);
+        try aro.Value.printString(bytes, str_ty, c.comp, buf.writer());
+        _ = buf.pop(); // printString adds a terminating " so we need to remove it
+        try buf.appendSlice("\\\"\"");
+
+        break :str try ZigTag.string_literal.create(c.arena, try c.arena.dupe(u8, buf.items));
+    } else try ZigTag.string_literal.create(c.arena, "\"static assertion failed\"");
+
+    const assert_node = try ZigTag.static_assert.create(c.arena, .{ .lhs = condition, .rhs = diagnostic });
+    try scope.appendNode(assert_node);
+}
+
 fn getTypeStr(c: *Context, ty: Type) ![]const u8 {
     var buf: std.ArrayListUnmanaged(u8) = .empty;
     defer buf.deinit(c.gpa);
@@ -1316,16 +1353,21 @@ fn transFnType(
     return ZigNode.initPayload(&payload.base);
 }
 
-fn transStmt(c: *Context, node: NodeIndex) TransError!ZigNode {
-    _ = c;
-    _ = node;
-    return error.UnsupportedTranslation;
+fn transStmt(c: *Context, scope: *Scope, stmt: NodeIndex) TransError!ZigNode {
+    const node_tags = c.tree.nodes.items(.tag);
+    switch (node_tags[@intFromEnum(stmt)]) {
+        .static_assert => {
+            try transStaticAssert(c, scope, stmt);
+            return ZigTag.declaration.init();
+        },
+        else => return fail(c, error.UnsupportedTranslation, c.tokenIndex(stmt).?, "TODO implement translation of stmt {s}", .{@tagName(node_tags[@intFromEnum(stmt)])}),
+    }
 }
 
 fn transCompoundStmtInline(c: *Context, compound: NodeIndex, block: *Scope.Block) TransError!void {
     const stmts = c.tree.childNodes(compound);
     for (stmts) |stmt| {
-        const result = try transStmt(c, stmt);
+        const result = try transStmt(c, &block.base, stmt);
         switch (result.tag()) {
             .declaration, .empty_block => {},
             else => try block.statements.append(result),

src/ast.zig

@@ -227,6 +227,9 @@ pub const Node = extern union {
         /// [1]type{val} ** count
         array_filler,
 
+        /// comptime { if (!(lhs)) @compileError(rhs); }
+        static_assert,
+
         pub const last_no_payload_tag = Tag.@"break";
         pub const no_payload_count = @intFromEnum(last_no_payload_tag) + 1;
 
@@ -336,6 +339,7 @@ pub const Node = extern union {
                 .div_exact,
                 .offset_of,
                 .helpers_cast,
+                .static_assert,
                 => Payload.BinOp,
 
                 .integer_literal,
@@ -753,7 +757,7 @@ pub const Payload = struct {
 /// Converts the nodes into a Zig Ast.
 /// Caller must free the source slice.
 pub fn render(gpa: Allocator, nodes: []const Node) !std.zig.Ast {
-    var ctx = Context{
+    var ctx: Context = .{
         .gpa = gpa,
         .buf = std.ArrayList(u8).init(gpa),
     };
@@ -803,7 +807,7 @@ pub fn render(gpa: Allocator, nodes: []const Node) !std.zig.Ast {
         .start = @as(u32, @intCast(ctx.buf.items.len)),
     });
 
-    return std.zig.Ast{
+    return .{
         .source = try ctx.buf.toOwnedSliceSentinel(0),
         .tokens = ctx.tokens.toOwnedSlice(),
         .nodes = ctx.nodes.toOwnedSlice(),
@@ -2127,6 +2131,61 @@ fn renderNode(c: *Context, node: Node) Allocator.Error!NodeIndex {
                 },
             };
         },
+        .static_assert => {
+            const payload = node.castTag(.static_assert).?.data;
+            const comptime_tok = try c.addToken(.keyword_comptime, "comptime");
+            const l_brace = try c.addToken(.l_brace, "{");
+
+            const if_tok = try c.addToken(.keyword_if, "if");
+            _ = try c.addToken(.l_paren, "(");
+            const cond = try c.addNode(.{
+                .tag = .bool_not,
+                .main_token = try c.addToken(.bang, "!"),
+                .data = .{
+                    .lhs = try renderNodeGrouped(c, payload.lhs),
+                    .rhs = undefined,
+                },
+            });
+            _ = try c.addToken(.r_paren, ")");
+
+            const compile_error_tok = try c.addToken(.builtin, "@compileError");
+            _ = try c.addToken(.l_paren, "(");
+            const err_msg = try renderNode(c, payload.rhs);
+            _ = try c.addToken(.r_paren, ")");
+            const compile_error = try c.addNode(.{
+                .tag = .builtin_call_two,
+                .main_token = compile_error_tok,
+                .data = .{ .lhs = err_msg, .rhs = 0 },
+            });
+
+            const if_node = try c.addNode(.{
+                .tag = .if_simple,
+                .main_token = if_tok,
+                .data = .{
+                    .lhs = cond,
+                    .rhs = compile_error,
+                },
+            });
+            _ = try c.addToken(.semicolon, ";");
+            _ = try c.addToken(.r_brace, "}");
+            const block_node = try c.addNode(.{
+                .tag = .block_two_semicolon,
+                .main_token = l_brace,
+                .data = .{
+                    .lhs = if_node,
+                    .rhs = 0,
+                },
+            });
+
+            return c.addNode(.{
+                .tag = .@"comptime",
+                .main_token = comptime_tok,
+                .data = .{
+                    .lhs = block_node,
+                    .rhs = undefined,
+                },
+            });
+        },
         .@"anytype" => unreachable, // Handled in renderParams
     }
 }
@@ -2527,6 +2586,7 @@ fn renderNodeGrouped(c: *Context, node: Node) !NodeIndex {
         .assign,
         .helpers_macro,
         .import_c_builtin,
+        .static_assert,
         => {
             // these should never appear in places where grouping might be needed.
             unreachable;

src/main.zig

@@ -86,8 +86,12 @@ fn translate(d: *aro.Driver, args: []const []const u8) !void {
         return;
     }
 
+    // TODO this should probably pass an arraylist for the generated source.
     var zig_tree = try Translator.translate(gpa, d.comp, c_tree);
-    defer zig_tree.deinit(gpa);
+    defer {
+        gpa.free(zig_tree.source);
+        zig_tree.deinit(gpa);
+    }
 
     const formatted = try zig_tree.render(gpa);
     defer gpa.free(formatted);

test/cases/translate/_Static_assert.c

@@ -2,5 +2,6 @@ _Static_assert(1 == 1, "");
 
 // translate
 // target=x86_64-linux
+// expect=fail
 //
 // tmp.c:1:1: warning: ignoring _Static_assert declaration