macOS: macho ld64.lld fixes

* bring `construct_linker_job_macho` to parity with
   `construct_linker_job_elf`
 * macho now sets `-error-limit`
 * macho on macOS now sets `-macosx_version_min` and `-sdk_version`
   to `10.13` when running `zig0`
 * macho now detects when `-l` prefix is not needed
 * macho on macOS detects system libraries in a case-insensitive manner
 * macho now ads user-specified libraries to linker command-line args
   when condition `is_native_os != true`
 * re-ordered some macho args positions to match elf positions

closes #5059
closes #5067

src-self-hosted/stage2.zig

@@ -1271,3 +1271,5 @@ export fn stage2_clang_arg_next(it: *ClangArgIterator) Error {
     };
     return .None;
 }
+
+export const stage2_is_zig0 = false;

src/link.cpp

@@ -2002,6 +2002,7 @@ static void construct_linker_job_elf(LinkJob *lj) {
         lj->args.append(buf_ptr(compiler_rt_o_path));
     }
 
+    // libraries
     for (size_t i = 0; i < g->link_libs_list.length; i += 1) {
         LinkLib *link_lib = g->link_libs_list.at(i);
         if (buf_eql_str(link_lib->name, "c")) {
@@ -2662,8 +2663,8 @@ static void construct_linker_job_coff(LinkJob *lj) {
 static void construct_linker_job_macho(LinkJob *lj) {
     CodeGen *g = lj->codegen;
 
-    // LLD MACH-O has no error limit option.
-    //lj->args.append("-error-limit=0");
+    lj->args.append("-error-limit");
+    lj->args.append("0");
     lj->args.append("-demangle");
 
     switch (g->linker_gc_sections) {
@@ -2736,6 +2737,7 @@ static void construct_linker_job_macho(LinkJob *lj) {
                 lj->args.append("-iphoneos_version_min");
             }
         }
+
         Buf *version_string = buf_sprintf("%d.%d.%d",
             g->zig_target->glibc_or_darwin_version->major,
             g->zig_target->glibc_or_darwin_version->minor,
@@ -2744,6 +2746,12 @@ static void construct_linker_job_macho(LinkJob *lj) {
 
         lj->args.append("-sdk_version");
         lj->args.append(buf_ptr(version_string));
+    } else if (stage2_is_zig0 && g->zig_target->os == OsMacOSX) {
+        // running `zig0`; `-pie` requires versions >= 10.5; select 10.13
+        lj->args.append("-macosx_version_min");
+        lj->args.append("10.13");
+        lj->args.append("-sdk_version");
+        lj->args.append("10.13");
     }
 
     if (g->out_type == OutTypeExe) {
@@ -2773,45 +2781,74 @@ static void construct_linker_job_macho(LinkJob *lj) {
         lj->args.append(lib_dir);
     }
 
+    // .o files
     for (size_t i = 0; i < g->link_objects.length; i += 1) {
         lj->args.append((const char *)buf_ptr(g->link_objects.at(i)));
     }
 
-    // libc++ dep
-    if (g->libcpp_link_lib != nullptr && g->out_type != OutTypeObj) {
-        lj->args.append(build_libcxxabi(g, lj->build_dep_prog_node));
-        lj->args.append(build_libcxx(g, lj->build_dep_prog_node));
-    }
-
     // compiler_rt on darwin is missing some stuff, so we still build it and rely on LinkOnce
     if (g->out_type == OutTypeExe || is_dyn_lib) {
         Buf *compiler_rt_o_path = build_compiler_rt(g, OutTypeLib, lj->build_dep_prog_node);
         lj->args.append(buf_ptr(compiler_rt_o_path));
     }
 
-    if (g->zig_target->is_native_os) {
-        for (size_t lib_i = 0; lib_i < g->link_libs_list.length; lib_i += 1) {
-            LinkLib *link_lib = g->link_libs_list.at(lib_i);
-            if (target_is_libc_lib_name(g->zig_target, buf_ptr(link_lib->name))) {
-                // handled by libSystem
-                continue;
-            }
-            if (strchr(buf_ptr(link_lib->name), '/') == nullptr) {
-                Buf *arg = buf_sprintf("-l%s", buf_ptr(link_lib->name));
-                lj->args.append(buf_ptr(arg));
-            } else {
-                lj->args.append(buf_ptr(link_lib->name));
-            }
+    // libraries
+    for (size_t lib_i = 0; lib_i < g->link_libs_list.length; lib_i += 1) {
+        LinkLib *link_lib = g->link_libs_list.at(lib_i);
+        if (buf_eql_str(link_lib->name, "c")) {
+            // libc is linked specially
+            continue;
         }
+        if (target_is_libcpp_lib_name(g->zig_target, buf_ptr(link_lib->name))) {
+            // libc++ is linked specially
+            continue;
+        }
+        if (g->zig_target->is_native_os && target_is_libc_lib_name(g->zig_target, buf_ptr(link_lib->name))) {
+            // libSystem is linked specially
+            continue;
+        }
+
+        Buf *arg;
+        if (buf_starts_with_str(link_lib->name, "/") || buf_ends_with_str(link_lib->name, ".a") ||
+            buf_ends_with_str(link_lib->name, ".dylib"))
+        {
+            arg = link_lib->name;
+        } else {
+            arg = buf_sprintf("-l%s", buf_ptr(link_lib->name));
+        }
+        lj->args.append(buf_ptr(arg));
+    }
+
+    // libc++ dep
+    if (g->libcpp_link_lib != nullptr && g->out_type != OutTypeObj) {
+        lj->args.append(build_libcxxabi(g, lj->build_dep_prog_node));
+        lj->args.append(build_libcxx(g, lj->build_dep_prog_node));
+    }
+
+    // libc dep
+    if (g->zig_target->is_native_os || stage2_is_zig0) {
         // on Darwin, libSystem has libc in it, but also you have to use it
         // to make syscalls because the syscall numbers are not documented
         // and change between versions.
         // so we always link against libSystem
         lj->args.append("-lSystem");
     }
+
+    for (size_t i = 0; i < g->framework_dirs.length; i += 1) {
+        const char *framework_dir = g->framework_dirs.at(i);
+        lj->args.append("-F");
+        lj->args.append(framework_dir);
+    }
+
+    for (size_t i = 0; i < g->darwin_frameworks.length; i += 1) {
+        lj->args.append("-framework");
+        lj->args.append(buf_ptr(g->darwin_frameworks.at(i)));
+    }
+
     switch (g->linker_allow_shlib_undefined) {
         case OptionalBoolNull:
-            if (!g->zig_target->is_native_os) {
+            if (!g->zig_target->is_native_os && !stage2_is_zig0) {
+                // TODO https://github.com/ziglang/zig/issues/5059
                 lj->args.append("-undefined");
                 lj->args.append("dynamic_lookup");
             }
@@ -2831,18 +2868,6 @@ static void construct_linker_job_macho(LinkJob *lj) {
             lj->args.append("-Bsymbolic");
             break;
     }
-
-    for (size_t i = 0; i < g->framework_dirs.length; i += 1) {
-        const char *framework_dir = g->framework_dirs.at(i);
-        lj->args.append("-F");
-        lj->args.append(framework_dir);
-    }
-
-    for (size_t i = 0; i < g->darwin_frameworks.length; i += 1) {
-        lj->args.append("-framework");
-        lj->args.append(buf_ptr(g->darwin_frameworks.at(i)));
-    }
-
 }
 
 static void construct_linker_job(LinkJob *lj) {
@@ -2920,7 +2945,6 @@ void codegen_link(CodeGen *g) {
 
     construct_linker_job(&lj);
 
-
     if (g->verbose_link) {
         for (size_t i = 0; i < lj.args.length; i += 1) {
             const char *space = (i != 0) ? " " : "";

src/stage2.cpp

@@ -322,3 +322,5 @@ enum Error stage2_clang_arg_next(struct Stage2ClangArgIterator *it) {
     const char *msg = "stage0 called stage2_clang_arg_next";
     stage2_panic(msg, strlen(msg));
 }
+
+const bool stage2_is_zig0 = true;

src/stage2.h

@@ -379,4 +379,7 @@ ZIG_EXTERN_C void stage2_clang_arg_iterator(struct Stage2ClangArgIterator *it,
 // ABI warning
 ZIG_EXTERN_C enum Error stage2_clang_arg_next(struct Stage2ClangArgIterator *it);
 
+// ABI warning
+ZIG_EXTERN_C const bool stage2_is_zig0;
+
 #endif

src/target.cpp

@@ -1209,39 +1209,46 @@ const char *target_libc_generic_name(const ZigTarget *target) {
 }
 
 bool target_is_libc_lib_name(const ZigTarget *target, const char *name) {
-    if (strcmp(name, "c") == 0)
+    auto equal = str_eql_str;
+    if (target->os == OsMacOSX)
+        equal = str_eql_str_ignore_case;
+
+    if (equal(name, "c"))
         return true;
 
     if (target_abi_is_gnu(target->abi) && target->os == OsWindows) {
         // mingw-w64
 
-        if (strcmp(name, "m") == 0)
+        if (equal(name, "m"))
             return true;
 
         return false;
     }
 
     if (target_abi_is_gnu(target->abi) || target_abi_is_musl(target->abi) || target_os_is_darwin(target->os)) {
-        if (strcmp(name, "m") == 0)
+        if (equal(name, "m"))
             return true;
-        if (strcmp(name, "rt") == 0)
+        if (equal(name, "rt"))
             return true;
-        if (strcmp(name, "pthread") == 0)
+        if (equal(name, "pthread"))
             return true;
-        if (strcmp(name, "crypt") == 0)
+        if (equal(name, "crypt"))
             return true;
-        if (strcmp(name, "util") == 0)
+        if (equal(name, "util"))
             return true;
-        if (strcmp(name, "xnet") == 0)
+        if (equal(name, "xnet"))
             return true;
-        if (strcmp(name, "resolv") == 0)
+        if (equal(name, "resolv"))
             return true;
-        if (strcmp(name, "dl") == 0)
+        if (equal(name, "dl"))
             return true;
-        if (strcmp(name, "util") == 0)
+        if (equal(name, "util"))
             return true;
     }
 
+    if (target_os_is_darwin(target->os) && equal(name, "System"))
+        return true;
+
     return false;
 }
 

src/util.hpp

@@ -96,6 +96,14 @@ static inline bool mem_eql_str(const char *mem, size_t mem_len, const char *str)
     return mem_eql_mem(mem, mem_len, str, strlen(str));
 }
 
+static inline bool str_eql_str(const char *a, const char* b) {
+    return mem_eql_mem(a, strlen(a), b, strlen(b));
+}
+
+static inline bool str_eql_str_ignore_case(const char *a, const char* b) {
+    return mem_eql_mem_ignore_case(a, strlen(a), b, strlen(b));
+}
+
 static inline bool is_power_of_2(uint64_t x) {
     return x != 0 && ((x & (~x + 1)) == x);
 }