Merge pull request #21920 from alexrp/nobuiltin

compiler: Improve handling of `-fno-builtin` and compiler-rt options

Author: alexrp

lib/c.zig

@@ -11,16 +11,14 @@ const native_os = builtin.os.tag;
 const native_arch = builtin.cpu.arch;
 const native_abi = builtin.abi;
 
+const linkage: std.builtin.GlobalLinkage = if (builtin.is_test) .internal else .strong;
+
 const is_wasm = switch (native_arch) {
     .wasm32, .wasm64 => true,
     else => false,
 };
-const is_msvc = switch (native_abi) {
-    .msvc => true,
-    else => false,
-};
 const is_freestanding = switch (native_os) {
-    .freestanding => true,
+    .freestanding, .other => true,
     else => false,
 };
 
@@ -30,14 +28,14 @@ comptime {
     }
 
     if (builtin.link_libc) {
-        @export(&strcmp, .{ .name = "strcmp", .linkage = .strong });
-        @export(&strncmp, .{ .name = "strncmp", .linkage = .strong });
-        @export(&strerror, .{ .name = "strerror", .linkage = .strong });
-        @export(&strlen, .{ .name = "strlen", .linkage = .strong });
-        @export(&strcpy, .{ .name = "strcpy", .linkage = .strong });
-        @export(&strncpy, .{ .name = "strncpy", .linkage = .strong });
-        @export(&strcat, .{ .name = "strcat", .linkage = .strong });
-        @export(&strncat, .{ .name = "strncat", .linkage = .strong });
+        @export(&strcmp, .{ .name = "strcmp", .linkage = linkage });
+        @export(&strncmp, .{ .name = "strncmp", .linkage = linkage });
+        @export(&strerror, .{ .name = "strerror", .linkage = linkage });
+        @export(&strlen, .{ .name = "strlen", .linkage = linkage });
+        @export(&strcpy, .{ .name = "strcpy", .linkage = linkage });
+        @export(&strncpy, .{ .name = "strncpy", .linkage = linkage });
+        @export(&strcat, .{ .name = "strcat", .linkage = linkage });
+        @export(&strncat, .{ .name = "strncat", .linkage = linkage });
     }
 }
 

lib/std/Target.zig

@@ -1076,7 +1076,7 @@ pub fn toElfMachine(target: Target) std.elf.EM {
 pub fn toCoffMachine(target: Target) std.coff.MachineType {
     return switch (target.cpu.arch) {
         .arm => .ARM,
-        .thumb => .THUMB,
+        .thumb => .ARMNT,
         .aarch64 => .ARM64,
         .loongarch32 => .LOONGARCH32,
         .loongarch64 => .LOONGARCH64,

src/Compilation.zig

@@ -89,7 +89,6 @@ windows_libs: std.StringArrayHashMapUnmanaged(void),
 version: ?std.SemanticVersion,
 libc_installation: ?*const LibCInstallation,
 skip_linker_dependencies: bool,
-no_builtin: bool,
 function_sections: bool,
 data_sections: bool,
 link_eh_frame_hdr: bool,
@@ -852,6 +851,7 @@ pub const cache_helpers = struct {
         hh.add(mod.fuzz);
         hh.add(mod.unwind_tables);
         hh.add(mod.structured_cfg);
+        hh.add(mod.no_builtin);
         hh.addListOfBytes(mod.cc_argv);
     }
 
@@ -1057,7 +1057,6 @@ pub const CreateOptions = struct {
     want_lto: ?bool = null,
     function_sections: bool = false,
     data_sections: bool = false,
-    no_builtin: bool = false,
     time_report: bool = false,
     stack_report: bool = false,
     link_eh_frame_hdr: bool = false,
@@ -1299,7 +1298,11 @@ pub fn create(gpa: Allocator, arena: Allocator, options: CreateOptions) !*Compil
                 },
                 .fully_qualified_name = "compiler_rt",
                 .cc_argv = &.{},
-                .inherited = .{},
+                .inherited = .{
+                    .stack_check = false,
+                    .stack_protector = 0,
+                    .no_builtin = true,
+                },
                 .global = options.config,
                 .parent = options.root_mod,
                 .builtin_mod = options.root_mod.getBuiltinDependency(),
@@ -1353,7 +1356,6 @@ pub fn create(gpa: Allocator, arena: Allocator, options: CreateOptions) !*Compil
         cache.hash.add(options.config.link_mode);
         cache.hash.add(options.function_sections);
         cache.hash.add(options.data_sections);
-        cache.hash.add(options.no_builtin);
         cache.hash.add(link_libc);
         cache.hash.add(options.config.link_libcpp);
         cache.hash.add(options.config.link_libunwind);
@@ -1490,7 +1492,6 @@ pub fn create(gpa: Allocator, arena: Allocator, options: CreateOptions) !*Compil
             .framework_dirs = options.framework_dirs,
             .llvm_opt_bisect_limit = options.llvm_opt_bisect_limit,
             .skip_linker_dependencies = options.skip_linker_dependencies,
-            .no_builtin = options.no_builtin,
             .job_queued_update_builtin_zig = have_zcu,
             .function_sections = options.function_sections,
             .data_sections = options.data_sections,
@@ -5261,7 +5262,7 @@ pub fn addCCArgs(
         try argv.append("-fdata-sections");
     }
 
-    if (comp.no_builtin) {
+    if (mod.no_builtin) {
         try argv.append("-fno-builtin");
     }
 
@@ -6154,7 +6155,6 @@ fn buildOutputFromZig(
 
     assert(output_mode != .Exe);
 
-    const unwind_tables = comp.link_eh_frame_hdr;
     const strip = comp.compilerRtStrip();
     const optimize_mode = comp.compilerRtOptMode();
 
@@ -6168,7 +6168,6 @@ fn buildOutputFromZig(
         .root_optimize_mode = optimize_mode,
         .root_strip = strip,
         .link_libc = comp.config.link_libc,
-        .any_unwind_tables = unwind_tables,
     });
 
     const root_mod = try Package.Module.create(arena, .{
@@ -6185,10 +6184,11 @@ fn buildOutputFromZig(
             .stack_protector = 0,
             .red_zone = comp.root_mod.red_zone,
             .omit_frame_pointer = comp.root_mod.omit_frame_pointer,
-            .unwind_tables = unwind_tables,
+            .unwind_tables = comp.root_mod.unwind_tables,
             .pic = comp.root_mod.pic,
             .optimize_mode = optimize_mode,
             .structured_cfg = comp.root_mod.structured_cfg,
+            .no_builtin = true,
             .code_model = comp.root_mod.code_model,
         },
         .global = config,
@@ -6237,7 +6237,6 @@ fn buildOutputFromZig(
         },
         .function_sections = true,
         .data_sections = true,
-        .no_builtin = true,
         .emit_h = null,
         .verbose_cc = comp.verbose_cc,
         .verbose_link = comp.verbose_link,
@@ -6262,16 +6261,24 @@ fn buildOutputFromZig(
     comp.queueLinkTaskMode(crt_file.full_object_path, output_mode);
 }
 
+pub const CrtFileOptions = struct {
+    function_sections: ?bool = null,
+    data_sections: ?bool = null,
+    omit_frame_pointer: ?bool = null,
+    pic: ?bool = null,
+    no_builtin: ?bool = null,
+};
+
 pub fn build_crt_file(
     comp: *Compilation,
     root_name: []const u8,
     output_mode: std.builtin.OutputMode,
-    pic: ?bool,
     misc_task_tag: MiscTask,
     prog_node: std.Progress.Node,
     /// These elements have to get mutated to add the owner module after it is
     /// created within this function.
     c_source_files: []CSourceFile,
+    options: CrtFileOptions,
 ) !void {
     const tracy_trace = trace(@src());
     defer tracy_trace.end();
@@ -6316,13 +6323,16 @@ pub fn build_crt_file(
             .sanitize_c = false,
             .sanitize_thread = false,
             .red_zone = comp.root_mod.red_zone,
-            .omit_frame_pointer = comp.root_mod.omit_frame_pointer,
+            // Some libcs (e.g. musl) are opinionated about -fomit-frame-pointer.
+            .omit_frame_pointer = options.omit_frame_pointer orelse comp.root_mod.omit_frame_pointer,
             .valgrind = false,
             .unwind_tables = false,
-            // Some CRT objects (rcrt1.o, Scrt1.o) are opinionated about PIC.
-            .pic = pic orelse comp.root_mod.pic,
+            // Some CRT objects (e.g. musl's rcrt1.o and Scrt1.o) are opinionated about PIC.
+            .pic = options.pic orelse comp.root_mod.pic,
             .optimize_mode = comp.compilerRtOptMode(),
             .structured_cfg = comp.root_mod.structured_cfg,
+            // Some libcs (e.g. musl) are opinionated about -fno-builtin.
+            .no_builtin = options.no_builtin orelse comp.root_mod.no_builtin,
         },
         .global = config,
         .cc_argv = &.{},
@@ -6350,6 +6360,8 @@ pub fn build_crt_file(
             .directory = null, // Put it in the cache directory.
             .basename = basename,
         },
+        .function_sections = options.function_sections orelse false,
+        .data_sections = options.data_sections orelse false,
         .emit_h = null,
         .c_source_files = c_source_files,
         .verbose_cc = comp.verbose_cc,

src/Package/Module.zig

@@ -31,6 +31,7 @@ unwind_tables: bool,
 cc_argv: []const []const u8,
 /// (SPIR-V) whether to generate a structured control flow graph or not
 structured_cfg: bool,
+no_builtin: bool,
 
 /// If the module is an `@import("builtin")` module, this is the `File` that
 /// is preallocated for it. Otherwise this field is null.
@@ -95,6 +96,7 @@ pub const CreateOptions = struct {
         sanitize_thread: ?bool = null,
         fuzz: ?bool = null,
         structured_cfg: ?bool = null,
+        no_builtin: ?bool = null,
     };
 };
 
@@ -298,6 +300,13 @@ pub fn create(arena: Allocator, options: CreateOptions) !*Package.Module {
         };
     };
 
+    const no_builtin = b: {
+        if (options.inherited.no_builtin) |x| break :b x;
+        if (options.parent) |p| break :b p.no_builtin;
+
+        break :b target.cpu.arch.isBpf();
+    };
+
     const llvm_cpu_features: ?[*:0]const u8 = b: {
         if (resolved_target.llvm_cpu_features) |x| break :b x;
         if (!options.global.use_llvm) break :b null;
@@ -350,6 +359,7 @@ pub fn create(arena: Allocator, options: CreateOptions) !*Package.Module {
         .unwind_tables = unwind_tables,
         .cc_argv = options.cc_argv,
         .structured_cfg = structured_cfg,
+        .no_builtin = no_builtin,
         .builtin_file = null,
     };
 
@@ -442,6 +452,7 @@ pub fn create(arena: Allocator, options: CreateOptions) !*Package.Module {
             .unwind_tables = unwind_tables,
             .cc_argv = &.{},
             .structured_cfg = structured_cfg,
+            .no_builtin = no_builtin,
             .builtin_file = new_file,
         };
         new_file.* = .{
@@ -502,6 +513,7 @@ pub fn createLimited(gpa: Allocator, options: LimitedOptions) Allocator.Error!*P
         .unwind_tables = undefined,
         .cc_argv = undefined,
         .structured_cfg = undefined,
+        .no_builtin = undefined,
         .builtin_file = null,
     };
     return mod;

src/codegen/llvm.zig

@@ -3222,8 +3222,6 @@ pub const Object = struct {
         owner_mod: *Package.Module,
         omit_frame_pointer: bool,
     ) Allocator.Error!void {
-        const comp = o.pt.zcu.comp;
-
         if (!owner_mod.red_zone) {
             try attributes.addFnAttr(.noredzone, &o.builder);
         }
@@ -3242,8 +3240,7 @@ pub const Object = struct {
         if (owner_mod.unwind_tables) {
             try attributes.addFnAttr(.{ .uwtable = Builder.Attribute.UwTable.default }, &o.builder);
         }
-        const target = owner_mod.resolved_target.result;
-        if (comp.skip_linker_dependencies or comp.no_builtin or target.cpu.arch.isBpf()) {
+        if (owner_mod.no_builtin) {
             // The intent here is for compiler-rt and libc functions to not generate
             // infinite recursion. For example, if we are compiling the memcpy function,
             // and llvm detects that the body is equivalent to memcpy, it may replace the
@@ -3258,6 +3255,7 @@ pub const Object = struct {
             try attributes.addFnAttr(.minsize, &o.builder);
             try attributes.addFnAttr(.optsize, &o.builder);
         }
+        const target = owner_mod.resolved_target.result;
         if (target.cpu.model.llvm_name) |s| {
             try attributes.addFnAttr(.{ .string = .{
                 .kind = try o.builder.string("target-cpu"),
@@ -5578,6 +5576,10 @@ pub const FuncGen = struct {
         var attributes: Builder.FunctionAttributes.Wip = .{};
         defer attributes.deinit(&o.builder);
 
+        if (self.ng.ownerModule().no_builtin) {
+            try attributes.addFnAttr(.nobuiltin, &o.builder);
+        }
+
         switch (modifier) {
             .auto, .never_tail, .always_tail => {},
             .never_inline => try attributes.addFnAttr(.@"noinline", &o.builder),
@@ -12728,6 +12730,8 @@ fn backendSupportsF16(target: std.Target) bool {
         .mips64,
         .mips64el,
         .s390x,
+        .sparc,
+        .sparc64,
         => false,
         .arm,
         .armeb,

src/glibc.zig

@@ -221,7 +221,7 @@ pub fn buildCrtFile(comp: *Compilation, crt_file: CrtFile, prog_node: std.Progre
                     .owner = comp.root_mod,
                 },
             };
-            return comp.build_crt_file("crti", .Obj, null, .@"glibc crti.o", prog_node, &files);
+            return comp.build_crt_file("crti", .Obj, .@"glibc crti.o", prog_node, &files, .{});
         },
         .crtn_o => {
             var args = std.ArrayList([]const u8).init(arena);
@@ -242,7 +242,7 @@ pub fn buildCrtFile(comp: *Compilation, crt_file: CrtFile, prog_node: std.Progre
                     .owner = undefined,
                 },
             };
-            return comp.build_crt_file("crtn", .Obj, null, .@"glibc crtn.o", prog_node, &files);
+            return comp.build_crt_file("crtn", .Obj, .@"glibc crtn.o", prog_node, &files, .{});
         },
         .scrt1_o => {
             const start_o: Compilation.CSourceFile = blk: {
@@ -295,7 +295,7 @@ pub fn buildCrtFile(comp: *Compilation, crt_file: CrtFile, prog_node: std.Progre
             };
             var files = [_]Compilation.CSourceFile{ start_o, abi_note_o, init_o };
             const basename = if (comp.config.output_mode == .Exe and !comp.config.pie) "crt1" else "Scrt1";
-            return comp.build_crt_file(basename, .Obj, null, .@"glibc Scrt1.o", prog_node, &files);
+            return comp.build_crt_file(basename, .Obj, .@"glibc Scrt1.o", prog_node, &files, .{});
         },
         .libc_nonshared_a => {
             const s = path.sep_str;
@@ -373,7 +373,6 @@ pub fn buildCrtFile(comp: *Compilation, crt_file: CrtFile, prog_node: std.Progre
                     "-fmerge-all-constants",
                     "-frounding-math",
                     "-Wno-unsupported-floating-point-opt", // For targets that don't support -frounding-math.
-                    "-fno-stack-protector",
                     "-fno-common",
                     "-fmath-errno",
                     "-ftls-model=initial-exec",
@@ -413,7 +412,7 @@ pub fn buildCrtFile(comp: *Compilation, crt_file: CrtFile, prog_node: std.Progre
                 files_index += 1;
             }
             const files = files_buf[0..files_index];
-            return comp.build_crt_file("c_nonshared", .Lib, null, .@"glibc libc_nonshared.a", prog_node, files);
+            return comp.build_crt_file("c_nonshared", .Lib, .@"glibc libc_nonshared.a", prog_node, files, .{});
         },
     }
 }

src/libcxx.zig

@@ -195,7 +195,7 @@ pub fn buildLibCXX(comp: *Compilation, prog_node: std.Progress.Node) BuildError!
             .valgrind = false,
             .optimize_mode = optimize_mode,
             .structured_cfg = comp.root_mod.structured_cfg,
-            .pic = comp.root_mod.pic,
+            .pic = if (target_util.supports_fpic(target)) true else null,
         },
         .global = config,
         .cc_argv = &.{},
@@ -278,9 +278,6 @@ pub fn buildLibCXX(comp: *Compilation, prog_node: std.Progress.Node) BuildError!
             try cflags.append("-faligned-allocation");
         }
 
-        if (target_util.supports_fpic(target)) {
-            try cflags.append("-fPIC");
-        }
         try cflags.append("-nostdinc++");
         try cflags.append("-std=c++23");
         try cflags.append("-Wno-user-defined-literals");