add --eh-frame-hdr conditionally

lib/std/build.zig

@@ -40,6 +40,7 @@ pub const Builder = struct {
     verbose_ir: bool,
     verbose_llvm_ir: bool,
     verbose_cimport: bool,
+    link_eh_frame_hdr: bool,
     invalid_user_input: bool,
     zig_exe: []const u8,
     default_step: *Step,
@@ -136,6 +137,7 @@ pub const Builder = struct {
             .verbose_ir = false,
             .verbose_llvm_ir = false,
             .verbose_cimport = false,
+            .link_eh_frame_hdr = false,
             .invalid_user_input = false,
             .allocator = allocator,
             .native_system_lib_paths = ArrayList([]const u8).init(allocator),
@@ -1175,6 +1177,8 @@ pub const LibExeObjStep = struct {
 
     valgrind_support: ?bool = null,
 
+    link_eh_frame_hdr: bool = false,
+
     /// Uses system Wine installation to run cross compiled Windows build artifacts.
     enable_wine: bool = false,
 
@@ -1623,6 +1627,10 @@ pub const LibExeObjStep = struct {
         self.verbose_cc = value;
     }
 
+    pub fn setLinkEhFrameHdr(self: *LibExeObjStep, value: bool) void {
+        self.link_eh_frame_hdr = value;
+    }
+
     pub fn setBuildMode(self: *LibExeObjStep, mode: builtin.Mode) void {
         self.build_mode = mode;
     }
@@ -1908,6 +1916,7 @@ pub const LibExeObjStep = struct {
         if (builder.verbose_llvm_ir) zig_args.append("--verbose-llvm-ir") catch unreachable;
         if (builder.verbose_link or self.verbose_link) zig_args.append("--verbose-link") catch unreachable;
         if (builder.verbose_cc or self.verbose_cc) zig_args.append("--verbose-cc") catch unreachable;
+        if (builder.link_eh_frame_hdr or self.link_eh_frame_hdr) zig_args.append("--eh-frame-hdr") catch unreachable;
 
         if (self.strip) {
             zig_args.append("--strip") catch unreachable;

src-self-hosted/compilation.zig

@@ -170,6 +170,8 @@ pub const Compilation = struct {
     verbose_llvm_ir: bool = false,
     verbose_link: bool = false,
 
+    link_eh_frame_hdr: bool = false,
+
     darwin_version_min: DarwinVersionMin = .None,
 
     test_filters: []const []const u8 = &[_][]const u8{},

src-self-hosted/link.zig

@@ -144,7 +144,9 @@ fn constructLinkerArgsElf(ctx: *Context) !void {
     //    lj->args.append(g->linker_script);
     //}
     try ctx.args.append("--gc-sections");
-    try ctx.args.append("--eh-frame-hdr");
+    if (ctx.comp.link_eh_frame_hdr) {
+        try ctx.args.append("--eh-frame-hdr");
+    }
 
     //lj->args.append("-m");
     //lj->args.append(getLDMOption(&g->zig_target));

src-self-hosted/main.zig

@@ -154,6 +154,7 @@ const usage_build_generic =
     \\  --static                     Output will be statically linked
     \\  --strip                      Exclude debug symbols
     \\  -target [name]               <arch><sub>-<os>-<abi> see the targets command
+    \\  --eh-frame-hdr               enable C++ exception handling by passing --eh-frame-hdr to linker
     \\  --verbose-tokenize           Turn on compiler debug output for tokenization
     \\  --verbose-ast-tree           Turn on compiler debug output for parsing into an AST (tree view)
     \\  --verbose-ast-fmt            Turn on compiler debug output for parsing into an AST (render source)
@@ -207,6 +208,7 @@ fn buildOutputType(allocator: *Allocator, args: []const []const u8, out_type: Co
     var verbose_llvm_ir = false;
     var verbose_cimport = false;
     var linker_rdynamic = false;
+    var link_eh_frame_hdr = false;
     var macosx_version_min: ?[]const u8 = null;
     var ios_version_min: ?[]const u8 = null;
 
@@ -369,6 +371,8 @@ fn buildOutputType(allocator: *Allocator, args: []const []const u8, out_type: Co
                     verbose_ir = true;
                 } else if (mem.eql(u8, arg, "--verbose-llvm-ir")) {
                     verbose_llvm_ir = true;
+                } else if (mem.eql(u8, arg, "--eh-frame-hdr")) {
+                    link_eh_frame_hdr = true;
                 } else if (mem.eql(u8, arg, "--verbose-cimport")) {
                     verbose_cimport = true;
                 } else if (mem.eql(u8, arg, "-rdynamic")) {
@@ -498,6 +502,8 @@ fn buildOutputType(allocator: *Allocator, args: []const []const u8, out_type: Co
     comp.verbose_llvm_ir = verbose_llvm_ir;
     comp.verbose_cimport = verbose_cimport;
 
+    comp.link_eh_frame_hdr = link_eh_frame_hdr;
+
     comp.err_color = color;
 
     comp.linker_rdynamic = linker_rdynamic;

src/all_types.hpp

@@ -2131,6 +2131,7 @@ struct CodeGen {
     bool have_winmain_crt_startup;
     bool have_dllmain_crt_startup;
     bool have_err_ret_tracing;
+    bool link_eh_frame_hdr;
     bool c_want_stdint;
     bool c_want_stdbool;
     bool verbose_tokenize;

src/codegen.cpp

@@ -8629,6 +8629,7 @@ static Error define_builtin_compile_vars(CodeGen *g) {
     cache_bool(&cache_hash, g->have_err_ret_tracing);
     cache_bool(&cache_hash, g->libc_link_lib != nullptr);
     cache_bool(&cache_hash, g->valgrind_support);
+    cache_bool(&cache_hash, g->link_eh_frame_hdr);
     cache_int(&cache_hash, detect_subsystem(g));
 
     Buf digest = BUF_INIT;
@@ -9510,6 +9511,7 @@ Error create_c_object_cache(CodeGen *g, CacheHash **out_cache_hash, bool verbose
     cache_int(cache_hash, g->build_mode);
     cache_bool(cache_hash, g->have_pic);
     cache_bool(cache_hash, g->have_sanitize_c);
+    cache_bool(cache_hash, g->link_eh_frame_hdr);
     cache_bool(cache_hash, want_valgrind_support(g));
     cache_bool(cache_hash, g->function_sections);
     for (size_t arg_i = 0; arg_i < g->clang_argv_len; arg_i += 1) {
@@ -10279,6 +10281,7 @@ static Error check_cache(CodeGen *g, Buf *manifest_dir, Buf *digest) {
         cache_buf_opt(ch, g->test_filter);
         cache_buf_opt(ch, g->test_name_prefix);
     }
+    cache_bool(ch, g->link_eh_frame_hdr);
     cache_bool(ch, g->is_single_threaded);
     cache_bool(ch, g->linker_rdynamic);
     cache_bool(ch, g->each_lib_rpath);

src/link.cpp

@@ -1647,7 +1647,9 @@ static void construct_linker_job_elf(LinkJob *lj) {
         lj->args.append("--gc-sections");
     }
 
-    lj->args.append("--eh-frame-hdr");
+    if (g->link_eh_frame_hdr) {
+        lj->args.append("--eh-frame-hdr");
+    }
 
     lj->args.append("-m");
     lj->args.append(getLDMOption(g->zig_target));

src/main.cpp

@@ -55,6 +55,7 @@ static int print_full_usage(const char *arg0, FILE *file, int return_code) {
         "  --color [auto|off|on]        enable or disable colored error messages\n"
         "  --disable-gen-h              do not generate a C header file (.h)\n"
         "  --disable-valgrind           omit valgrind client requests in debug builds\n"
+        "  --eh-frame-hdr               enable C++ exception handling by passing --eh-frame-hdr to linker\n"
         "  --enable-valgrind            include valgrind client requests release builds\n"
         "  -fstack-check                enable stack probing in unsafe builds\n"
         "  -fno-stack-check             disable stack probing in safe builds\n"
@@ -477,6 +478,7 @@ int main(int argc, char **argv) {
     bool verbose_llvm_ir = false;
     bool verbose_cimport = false;
     bool verbose_cc = false;
+    bool link_eh_frame_hdr = false;
     ErrColor color = ErrColorAuto;
     CacheOpt enable_cache = CacheOptAuto;
     Buf *dynamic_linker = nullptr;
@@ -715,6 +717,8 @@ int main(int argc, char **argv) {
                 valgrind_support = ValgrindSupportEnabled;
             } else if (strcmp(arg, "--disable-valgrind") == 0) {
                 valgrind_support = ValgrindSupportDisabled;
+            } else if (strcmp(arg, "--eh-frame-hdr") == 0) {
+                link_eh_frame_hdr = true;
             } else if (strcmp(arg, "-fPIC") == 0) {
                 want_pic = WantPICEnabled;
             } else if (strcmp(arg, "-fno-PIC") == 0) {
@@ -1191,6 +1195,7 @@ int main(int argc, char **argv) {
                     override_lib_dir, libc, cache_dir_buf, cmd == CmdTest, root_progress_node);
             if (llvm_argv.length >= 2) codegen_set_llvm_argv(g, llvm_argv.items + 1, llvm_argv.length - 2);
             g->valgrind_support = valgrind_support;
+            g->link_eh_frame_hdr = link_eh_frame_hdr;
             g->want_pic = want_pic;
             g->want_stack_check = want_stack_check;
             g->want_sanitize_c = want_sanitize_c;