zig

commit 55a8b7e1fa4d36f5283d1f8655d3baecfefeffa3 (tree)
parent 4ebf483e0da2f85e00918b7900afaf73e111b727
Author: Andrew Kelley <andrew@ziglang.org>
Date:   Fri,  7 Apr 2023 19:58:55 -0400

Merge pull request #15097 from zachcheu/add-wrap-flag

add linker -wrap flag
Diffstat:
M
src/Compilation.zig
 | 
6
+++++-
M
src/link.zig
 | 
7
+++++++
M
src/link/Elf.zig
 | 
6
++++++
M
src/main.zig
 | 
6
++++++

4 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/src/Compilation.zig b/src/Compilation.zig
@@ -494,6 +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{},
+    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{},
@@ -825,7 +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;
             }
@@ -1438,6 +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,
+            .symbol_wrap_set = options.symbol_wrap_set,
             .strip = strip,
             .is_native_os = options.is_native_os,
             .is_native_abi = options.is_native_abi,
@@ -2259,6 +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.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);
diff --git a/src/link.zig b/src/link.zig
@@ -188,6 +188,13 @@ pub const Options = struct {
     /// 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,
diff --git a/src/link/Elf.zig b/src/link/Elf.zig
@@ -1386,6 +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.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);
@@ -1665,6 +1666,11 @@ fn linkWithLLD(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !v
                 try argv.append(rpath);
             }
         }
+
+        for (self.base.options.symbol_wrap_set.keys()) |symbol_name| {
+            try argv.appendSlice(&.{ "-wrap", symbol_name });
+        }
+
         if (self.base.options.each_lib_rpath) {
             var test_path = std.ArrayList(u8).init(self.base.allocator);
             defer test_path.deinit();
diff --git a/src/main.zig b/src/main.zig
@@ -874,6 +874,8 @@ fn buildOutputType(
     var rpath_list = std.ArrayList([]const u8).init(gpa);
     defer rpath_list.deinit();
 
+    var symbol_wrap_set: std.StringArrayHashMapUnmanaged(void) = .{};
+
     var c_source_files = std.ArrayList(Compilation.CSourceFile).init(gpa);
     defer c_source_files.deinit();
 
@@ -2155,6 +2157,9 @@ fn buildOutputType(
                             next_arg,
                         });
                     };
+                } else if (mem.eql(u8, arg, "-wrap")) {
+                    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());
@@ -3039,6 +3044,7 @@ fn buildOutputType(
         .clang_argv = clang_argv.items,
         .lib_dirs = lib_dirs.items,
         .rpath_list = rpath_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,