Commit b086b7da9e

Andrew Kelley <andrew@ziglang.org>
2023-04-07 16:51:39
zig cc: complete the -wrap flag implementation
* use a set instead of a list * use of this flag currently requires LLD * add documentation * make it only a zig cc compatibility flag for now because I personally think this is an anti-feature.
1 parent 1fdea55
Changed files (4)
src/link/Elf.zig
@@ -1386,7 +1386,7 @@ fn linkWithLLD(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !v
             man.hash.add(stack_size);
             man.hash.add(self.base.options.build_id);
         }
-        man.hash.addListOfBytes(self.base.options.wrap_list);
+        man.hash.addListOfBytes(self.base.options.symbol_wrap_set.keys());
         man.hash.add(self.base.options.skip_linker_dependencies);
         man.hash.add(self.base.options.z_nodelete);
         man.hash.add(self.base.options.z_notext);
@@ -1667,14 +1667,8 @@ fn linkWithLLD(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !v
             }
         }
 
-        // wrap
-        var wrap_table = std.StringHashMap(void).init(self.base.allocator);
-        defer wrap_table.deinit();
-        for (self.base.options.wrap_list) |wrap| {
-            if ((try wrap_table.fetchPut(wrap, {})) == null) {
-                try argv.append("-wrap");
-                try argv.append(wrap);
-            }
+        for (self.base.options.symbol_wrap_set.keys()) |symbol_name| {
+            try argv.appendSlice(&.{ "-wrap", symbol_name });
         }
 
         if (self.base.options.each_lib_rpath) {
src/Compilation.zig
@@ -494,7 +494,7 @@ pub const InitOptions = struct {
     clang_argv: []const []const u8 = &[0][]const u8{},
     lib_dirs: []const []const u8 = &[0][]const u8{},
     rpath_list: []const []const u8 = &[0][]const u8{},
-    wrap_list: []const []const u8 = &[0][]const u8{},
+    symbol_wrap_set: std.StringArrayHashMapUnmanaged(void) = .{},
     c_source_files: []const CSourceFile = &[0]CSourceFile{},
     link_objects: []LinkObject = &[0]LinkObject{},
     framework_dirs: []const []const u8 = &[0][]const u8{},
@@ -826,7 +826,8 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
                 options.output_mode == .Lib or
                 options.linker_script != null or options.version_script != null or
                 options.emit_implib != null or
-                build_id)
+                build_id or
+                options.symbol_wrap_set.count() > 0)
             {
                 break :blk true;
             }
@@ -1439,7 +1440,7 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
             .wasi_emulated_libs = options.wasi_emulated_libs,
             .lib_dirs = options.lib_dirs,
             .rpath_list = options.rpath_list,
-            .wrap_list = options.wrap_list,
+            .symbol_wrap_set = options.symbol_wrap_set,
             .strip = strip,
             .is_native_os = options.is_native_os,
             .is_native_abi = options.is_native_abi,
@@ -2261,7 +2262,7 @@ fn addNonIncrementalStuffToCacheManifest(comp: *Compilation, man: *Cache.Manifes
     man.hash.add(comp.bin_file.options.rdynamic);
     man.hash.addListOfBytes(comp.bin_file.options.lib_dirs);
     man.hash.addListOfBytes(comp.bin_file.options.rpath_list);
-    man.hash.addListOfBytes(comp.bin_file.options.wrap_list);
+    man.hash.addListOfBytes(comp.bin_file.options.symbol_wrap_set.keys());
     man.hash.add(comp.bin_file.options.each_lib_rpath);
     man.hash.add(comp.bin_file.options.build_id);
     man.hash.add(comp.bin_file.options.skip_linker_dependencies);
src/link.zig
@@ -183,12 +183,18 @@ pub const Options = struct {
     wasi_emulated_libs: []const wasi_libc.CRTFile,
     lib_dirs: []const []const u8,
     rpath_list: []const []const u8,
-    wrap_list: []const []const u8,
 
     /// List of symbols forced as undefined in the symbol table
     /// thus forcing their resolution by the linker.
     /// Corresponds to `-u <symbol>` for ELF/MachO and `/include:<symbol>` for COFF/PE.
     force_undefined_symbols: std.StringArrayHashMapUnmanaged(void),
+    /// Use a wrapper function for symbol. Any undefined reference to symbol
+    /// will be resolved to __wrap_symbol. Any undefined reference to
+    /// __real_symbol will be resolved to symbol. This can be used to provide a
+    /// wrapper for a system function. The wrapper function should be called
+    /// __wrap_symbol. If it wishes to call the system function, it should call
+    /// __real_symbol.
+    symbol_wrap_set: std.StringArrayHashMapUnmanaged(void),
 
     version: ?std.builtin.Version,
     compatibility_version: ?std.builtin.Version,
src/main.zig
@@ -487,7 +487,6 @@ const usage_build_generic =
     \\  -fno-compiler-rt               Prevent including compiler-rt symbols in output
     \\  -rdynamic                      Add all symbols to the dynamic symbol table
     \\  -rpath [path]                  Add directory to the runtime library search path
-    \\  -wrap [symbol]                 Override the symbol with the wrapped symbol definition
     \\  -feach-lib-rpath               Ensure adding rpath for each used dynamic library
     \\  -fno-each-lib-rpath            Prevent adding rpath for each used dynamic library
     \\  -fallow-shlib-undefined        Allows undefined symbols in shared libraries
@@ -875,8 +874,7 @@ fn buildOutputType(
     var rpath_list = std.ArrayList([]const u8).init(gpa);
     defer rpath_list.deinit();
 
-    var wrap_list = std.ArrayList([]const u8).init(gpa);
-    defer wrap_list.deinit();
+    var symbol_wrap_set: std.StringArrayHashMapUnmanaged(void) = .{};
 
     var c_source_files = std.ArrayList(Compilation.CSourceFile).init(gpa);
     defer c_source_files.deinit();
@@ -1479,9 +1477,6 @@ fn buildOutputType(
                         try system_libs.put(arg["-needed-l".len..], .{ .needed = true });
                     } else if (mem.startsWith(u8, arg, "-weak-l")) {
                         try system_libs.put(arg["-weak-l".len..], .{ .weak = true });
-                    } else if (mem.eql(u8, arg, "-wrap")){
-                        try wrap_list.append(arg);
-                        try wrap_list.append(args_iter.nextOrFatal());
                     } else if (mem.startsWith(u8, arg, "-D")) {
                         try clang_argv.append(arg);
                     } else if (mem.startsWith(u8, arg, "-I")) {
@@ -2163,11 +2158,8 @@ fn buildOutputType(
                         });
                     };
                 } else if (mem.eql(u8, arg, "-wrap")) {
-                    i += 1;
-                    if (i >= linker_args.items.len) {
-                        fatal("expected linker arg after '{s}'", .{arg});
-                    }
-                    try wrap_list.append(linker_args.items[i]);
+                    const next_arg = linker_args_it.nextOrFatal();
+                    try symbol_wrap_set.put(arena, next_arg, {});
                 } else if (mem.startsWith(u8, arg, "/subsystem:")) {
                     var split_it = mem.splitBackwards(u8, arg, ":");
                     subsystem = try parseSubSystem(split_it.first());
@@ -3052,7 +3044,7 @@ fn buildOutputType(
         .clang_argv = clang_argv.items,
         .lib_dirs = lib_dirs.items,
         .rpath_list = rpath_list.items,
-        .wrap_list = wrap_list.items,
+        .symbol_wrap_set = symbol_wrap_set,
         .c_source_files = c_source_files.items,
         .link_objects = link_objects.items,
         .framework_dirs = framework_dirs.items,