Add CompileStep APIs to Build.Module.

build.zig

@@ -35,9 +35,13 @@ pub fn build(b: *std.Build) !void {
     const skip_install_lib_files = b.option(bool, "no-lib", "skip copying of lib/ files and langref to installation prefix. Useful for development") orelse deprecated_skip_install_lib_files;
     const skip_install_langref = b.option(bool, "no-langref", "skip copying of langref to the installation prefix") orelse skip_install_lib_files;
 
+    const docgen_module = b.createModule(.{
+        .source_file = .{ .path = "doc/docgen.zig" },
+    });
+
     const docgen_exe = b.addExecutable(.{
         .name = "docgen",
-        .root_source_file = .{ .path = "doc/docgen.zig" },
+        .main_module = docgen_module,
         .target = .{},
         .optimize = .Debug,
     });
@@ -64,9 +68,12 @@ pub fn build(b: *std.Build) !void {
     legacy_write_to_cache.addCopyFileToSource(langref_file, "zig-cache/langref.html");
     docs_step.dependOn(&legacy_write_to_cache.step);
 
+    const check_case_mod = b.createModule(.{
+        .source_file = .{ .path = "test/src/Cases.zig" },
+    });
     const check_case_exe = b.addExecutable(.{
         .name = "check-case",
-        .root_source_file = .{ .path = "test/src/Cases.zig" },
+        .main_module = check_case_mod,
         .optimize = optimize,
     });
     check_case_exe.main_pkg_path = ".";
@@ -537,9 +544,12 @@ fn addCompilerStep(
     optimize: std.builtin.OptimizeMode,
     target: std.zig.CrossTarget,
 ) *std.Build.CompileStep {
+    const exe_mod = b.createModule(.{
+        .source_file = .{ .path = "src/main.zig" },
+    });
     const exe = b.addExecutable(.{
         .name = "zig",
-        .root_source_file = .{ .path = "src/main.zig" },
+        .main_module = exe_mod,
         .target = target,
         .optimize = optimize,
     });

lib/std/Build.zig

@@ -20,6 +20,7 @@ const Sha256 = std.crypto.hash.sha2.Sha256;
 const Build = @This();
 
 pub const Cache = @import("Build/Cache.zig");
+pub const Module = @import("Build/Module.zig");
 
 /// deprecated: use `CompileStep`.
 pub const LibExeObjStep = CompileStep;
@@ -448,7 +449,7 @@ pub fn addOptions(self: *Build) *OptionsStep {
 
 pub const ExecutableOptions = struct {
     name: []const u8,
-    root_source_file: ?FileSource = null,
+    main_module: *Module,
     version: ?std.builtin.Version = null,
     target: CrossTarget = .{},
     optimize: std.builtin.Mode = .Debug,
@@ -463,7 +464,7 @@ pub const ExecutableOptions = struct {
 pub fn addExecutable(b: *Build, options: ExecutableOptions) *CompileStep {
     return CompileStep.create(b, .{
         .name = options.name,
-        .root_source_file = options.root_source_file,
+        .main_module = options.main_module,
         .version = options.version,
         .target = options.target,
         .optimize = options.optimize,
@@ -479,7 +480,7 @@ pub fn addExecutable(b: *Build, options: ExecutableOptions) *CompileStep {
 
 pub const ObjectOptions = struct {
     name: []const u8,
-    root_source_file: ?FileSource = null,
+    main_module: *Module,
     target: CrossTarget,
     optimize: std.builtin.Mode,
     max_rss: usize = 0,
@@ -492,7 +493,7 @@ pub const ObjectOptions = struct {
 pub fn addObject(b: *Build, options: ObjectOptions) *CompileStep {
     return CompileStep.create(b, .{
         .name = options.name,
-        .root_source_file = options.root_source_file,
+        .main_module = options.main_module,
         .target = options.target,
         .optimize = options.optimize,
         .kind = .obj,
@@ -506,7 +507,7 @@ pub fn addObject(b: *Build, options: ObjectOptions) *CompileStep {
 
 pub const SharedLibraryOptions = struct {
     name: []const u8,
-    root_source_file: ?FileSource = null,
+    main_module: *Module,
     version: ?std.builtin.Version = null,
     target: CrossTarget,
     optimize: std.builtin.Mode,
@@ -520,7 +521,7 @@ pub const SharedLibraryOptions = struct {
 pub fn addSharedLibrary(b: *Build, options: SharedLibraryOptions) *CompileStep {
     return CompileStep.create(b, .{
         .name = options.name,
-        .root_source_file = options.root_source_file,
+        .main_module = options.main_module,
         .kind = .lib,
         .linkage = .dynamic,
         .version = options.version,
@@ -536,7 +537,7 @@ pub fn addSharedLibrary(b: *Build, options: SharedLibraryOptions) *CompileStep {
 
 pub const StaticLibraryOptions = struct {
     name: []const u8,
-    root_source_file: ?FileSource = null,
+    main_module: *Module,
     target: CrossTarget,
     optimize: std.builtin.Mode,
     version: ?std.builtin.Version = null,
@@ -550,7 +551,7 @@ pub const StaticLibraryOptions = struct {
 pub fn addStaticLibrary(b: *Build, options: StaticLibraryOptions) *CompileStep {
     return CompileStep.create(b, .{
         .name = options.name,
-        .root_source_file = options.root_source_file,
+        .main_module = options.main_module,
         .kind = .lib,
         .linkage = .static,
         .version = options.version,
@@ -566,7 +567,7 @@ pub fn addStaticLibrary(b: *Build, options: StaticLibraryOptions) *CompileStep {
 
 pub const TestOptions = struct {
     name: []const u8 = "test",
-    root_source_file: FileSource,
+    main_module: *Module,
     target: CrossTarget = .{},
     optimize: std.builtin.Mode = .Debug,
     version: ?std.builtin.Version = null,
@@ -583,7 +584,7 @@ pub fn addTest(b: *Build, options: TestOptions) *CompileStep {
     return CompileStep.create(b, .{
         .name = options.name,
         .kind = .@"test",
-        .root_source_file = options.root_source_file,
+        .main_module = options.main_module,
         .target = options.target,
         .optimize = options.optimize,
         .max_rss = options.max_rss,
@@ -621,40 +622,44 @@ pub fn addAssembly(b: *Build, options: AssemblyOptions) *CompileStep {
 /// it available to other packages which depend on this one.
 /// `createModule` can be used instead to create a private module.
 pub fn addModule(b: *Build, name: []const u8, options: CreateModuleOptions) *Module {
-    const module = b.createModule(options);
+    const module = Module.create(b, name, options);
     b.modules.put(b.dupe(name), module) catch @panic("OOM");
     return module;
 }
 
+pub const CSourceFiles = struct {
+    files: []const []const u8,
+    flags: []const []const u8,
+};
+
+pub const CSourceFile = struct {
+    source: FileSource,
+    args: []const []const u8,
+
+    pub fn dupe(self: CSourceFile, b: *std.Build) CSourceFile {
+        return .{
+            .source = self.source.dupe(b),
+            .args = b.dupeStrings(self.args),
+        };
+    }
+};
+
 pub const ModuleDependency = struct {
     name: []const u8,
     module: *Module,
 };
 
 pub const CreateModuleOptions = struct {
-    source_file: FileSource,
+    source_file: ?FileSource = null,
+    c_source_files: ?CSourceFiles = null,
     dependencies: []const ModuleDependency = &.{},
 };
 
 /// This function creates a private module, to be used by the current package,
 /// but not exposed to other packages depending on this one.
 /// `addModule` can be used instead to create a public module.
 pub fn createModule(b: *Build, options: CreateModuleOptions) *Module {
-    const module = b.allocator.create(Module) catch @panic("OOM");
-    module.* = .{
-        .builder = b,
-        .source_file = options.source_file,
-        .dependencies = moduleDependenciesToArrayHashMap(b.allocator, options.dependencies),
-    };
-    return module;
-}
-
-fn moduleDependenciesToArrayHashMap(arena: Allocator, deps: []const ModuleDependency) std.StringArrayHashMap(*Module) {
-    var result = std.StringArrayHashMap(*Module).init(arena);
-    for (deps) |dep| {
-        result.put(dep.name, dep.module) catch @panic("OOM");
-    }
-    return result;
+    return Module.create(b, null, options);
 }
 
 /// Initializes a RunStep with argv, which must at least have the path to the
@@ -1548,15 +1553,6 @@ pub fn runBuild(b: *Build, build_zig: anytype) anyerror!void {
     }
 }
 
-pub const Module = struct {
-    builder: *Build,
-    /// This could either be a generated file, in which case the module
-    /// contains exactly one file, or it could be a path to the root source
-    /// file of directory of files which constitute the module.
-    source_file: FileSource,
-    dependencies: std.StringArrayHashMap(*Module),
-};
-
 /// A file that is generated by a build step.
 /// This struct is an interface that is meant to be used with `@fieldParentPtr` to implement the actual path logic.
 pub const GeneratedFile = struct {