Pass --allow-unknown-exports to wasmtime

Also skip exporting non-function symbols when we're building a WASI command using the stage2 llvm backend.

lib/std/build.zig

@@ -2659,6 +2659,8 @@ pub const LibExeObjStep = struct {
                         try zig_args.append(bin_name);
                         try zig_args.append("--test-cmd");
                         try zig_args.append("--dir=.");
+                        try zig_args.append("--test-cmd");
+                        try zig_args.append("--allow-unknown-exports"); // TODO: Remove when stage2 is default compiler
                         try zig_args.append("--test-cmd-bin");
                     } else {
                         try zig_args.append("--test-no-exec");

src/Compilation.zig

@@ -1882,9 +1882,9 @@ pub fn destroy(self: *Compilation) void {
     self.astgen_wait_group.deinit();
 
     for (self.export_symbol_names.items) |symbol_name| {
-        self.gpa.free(symbol_name);
+        gpa.free(symbol_name);
     }
-    self.export_symbol_names.deinit(self.gpa);
+    self.export_symbol_names.deinit(gpa);
 
     // This destroys `self`.
     self.arena_state.promote(gpa).deinit();

src/link/Wasm.zig

@@ -1256,8 +1256,15 @@ fn linkWithLLD(self: *Wasm, comp: *Compilation) !void {
                         try argv.append(try std.fmt.allocPrint(arena, "--export={s}", .{symbol_name}));
                     }
                 } else {
+                    const skip_export_non_fn = target.os.tag == .wasi and
+                        self.base.options.wasi_exec_model == .command;
                     for (module.decl_exports.values()) |exports| {
                         for (exports) |exprt| {
+                            if (skip_export_non_fn and exprt.exported_decl.ty.zigTypeTag() != .Fn) {
+                                // skip exporting symbols when we're building a WASI command
+                                // and the symbol is not a function
+                                continue;
+                            }
                             const symbol_name = exprt.exported_decl.name;
                             const arg = try std.fmt.allocPrint(arena, "--export={s}", .{symbol_name});
                             try argv.append(arg);

src/stage1.zig

@@ -468,13 +468,9 @@ export fn stage2_fetch_file(
     return contents.ptr;
 }
 
-export fn stage2_append_symbol(stage1: *Module, name_ptr: ?[*:0]const u8) Error {
+export fn stage2_append_symbol(stage1: *Module, name_ptr: [*c]const u8, name_len: usize) Error {
+    if (name_len == 0) return Error.None;
     const comp = @intToPtr(*Compilation, stage1.userdata);
-
-    if (name_ptr) |unwrapped_name| {
-        const symbol_name = std.mem.sliceTo(unwrapped_name, 0);
-        if (symbol_name.len == 0) return Error.None;
-        comp.export_symbol_names.append(comp.gpa, symbol_name) catch return Error.OutOfMemory;
-    }
+    comp.export_symbol_names.append(comp.gpa, name_ptr[0..name_len]) catch return Error.OutOfMemory;
     return Error.None;
 }

src/stage1/codegen.cpp

@@ -9912,7 +9912,7 @@ void codegen_build_object(CodeGen *g) {
         auto export_it = g->exported_symbol_names.entry_iterator();
         decltype(g->exported_symbol_names)::Entry *curr_entry = nullptr;
         while ((curr_entry = export_it.next()) != nullptr) {
-            if ((err = stage2_append_symbol(&g->stage1, buf_ptr(curr_entry->key)))) {
+            if ((err = stage2_append_symbol(&g->stage1, buf_ptr(curr_entry->key), buf_len(curr_entry->key)))) {
                 fprintf(stderr, "Unable to export symbol '%s': %s\n", buf_ptr(curr_entry->key), err_str(err));
             }
         }

src/stage1/stage2.h

@@ -183,6 +183,6 @@ ZIG_EXTERN_C const char *stage2_add_link_lib(struct ZigStage1 *stage1,
         const char *symbol_name_ptr, size_t symbol_name_len);
 
 // ABI warning
-ZIG_EXTERN_C enum Error stage2_append_symbol(struct ZigStage1 *stage1, const char *name_ptr);
+ZIG_EXTERN_C enum Error stage2_append_symbol(struct ZigStage1 *stage1, const char *name_ptr, size_t name_len);
 
 #endif

src/stage1/zig0.cpp

@@ -555,7 +555,7 @@ struct Stage2SemVer stage2_version(void) {
     return {ZIG_VERSION_MAJOR, ZIG_VERSION_MINOR, ZIG_VERSION_PATCH};
 }
 
-Error stage2_append_symbol(struct ZigStage1 *stage1, const char *name_ptr)
+Error stage2_append_symbol(struct ZigStage1 *stage1, const char *name_ptr, size_t name_len)
 {
     return ErrorNone;
 }