[Mach-O] Add -search_paths_first and -search_dylibs_first

macho/cmdline.cc

@@ -54,6 +54,8 @@ Options:
                               Set platform, platform version and SDK version
   -rpath <PATH>               Add PATH to the runpath search path list
   -syslibroot <DIR>           Prepend DIR to library search paths
+  -search_paths_first
+  -search_dylibs_first
   -t                          Print out each file the linker loads
   -v                          Report version information)";
 
@@ -265,11 +267,12 @@ std::vector<std::string> parse_nonpositional_args(Context<E> &ctx) {
       ctx.arg.platform_sdk_version = parse_version(ctx, arg3);
     } else if (read_arg("-rpath")) {
       ctx.arg.rpath.push_back(std::string(arg));
-    } else if (read_flag("-search_dylibs_first")) {
-      Fatal(ctx) << "-search_dylibs_first is not supported";
-    } else if (read_flag("-search_paths_first")) {
     } else if (read_arg("-syslibroot")) {
       ctx.arg.syslibroot.push_back(std::string(arg));
+    } else if (read_flag("-search_paths_first")) {
+      ctx.arg.search_paths_first = true;
+    } else if (read_flag("-search_dylibs_first")) {
+      ctx.arg.search_paths_first = false;
     } else if (read_flag("-t")) {
       ctx.arg.trace = true;
     } else if (read_flag("-v")) {

macho/main.cc

@@ -269,14 +269,25 @@ MappedFile<Context<E>> *find_framework(Context<E> &ctx, std::string name) {
 
 template <typename E>
 MappedFile<Context<E>> *find_library(Context<E> &ctx, std::string name) {
+  auto search = [&](std::vector<std::string> extn) -> MappedFile<Context<E>> * {
     for (std::string dir : ctx.arg.library_paths) {
-    for (std::string ext : {".tbd", ".dylib", ".a"}) {
-      std::string path = dir + "/lib" + name + ext;
+      for (std::string e : extn) {
+        std::string path = dir + "/lib" + name + e;
         if (MappedFile<Context<E>> *mf = MappedFile<Context<E>>::open(ctx, path))
           return mf;
       }
     }
     return nullptr;
+  };
+
+  // -search_paths_first
+  if (ctx.arg.search_paths_first)
+    return search({".tbd", ".dylib", ".a"});
+
+  // -search_dylibs_first
+  if (MappedFile<Context<E>> *mf = search({".tbd", ".dylib"}))
+    return mf;
+  return search({".a"});
 }
 
 template <typename E>

macho/mold.h

@@ -800,6 +800,7 @@ struct Context {
     bool dynamic = true;
     bool fatal_warnings = false;
     bool noinhibit_exec = false;
+    bool search_paths_first = true;
     bool trace = false;
     i64 arch = CPU_TYPE_ARM64;
     i64 headerpad = 256;

test/macho/search-dylibs-first.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+export LC_ALL=C
+set -e
+CC="${TEST_CC:-cc}"
+CXX="${TEST_CXX:-c++}"
+GCC="${TEST_GCC:-gcc}"
+GXX="${TEST_GXX:-g++}"
+OBJDUMP="${OBJDUMP:-objdump}"
+MACHINE="${MACHINE:-$(uname -m)}"
+testname=$(basename "$0" .sh)
+echo -n "Testing $testname ... "
+cd "$(dirname "$0")"/../..
+t=out/test/macho/$testname
+mkdir -p $t
+
+cat <<EOF | $CC -o $t/a.o -c -xc -
+#include <stdio.h>
+void say() {
+  printf("Hello\n");
+}
+EOF
+
+cat <<EOF | $CC -o $t/b.o -c -xc -
+#include <stdio.h>
+void say() {
+  printf("Howdy\n");
+}
+EOF
+
+cat <<EOF | $CC -o $t/c.o -c -xc -
+void say();
+int main() {
+  say();
+}
+EOF
+
+mkdir -p $t/x $t/y
+
+ar rcs $t/x/libfoo.a $t/a.o
+$CC -shared -o $t/y/libfoo.dylib $t/b.o
+
+clang --ld-path=./ld64 -o $t/exe $t/c.o -Wl,-L$t/x -Wl,-L$t/y -lfoo
+$t/exe | grep -q Hello
+
+clang --ld-path=./ld64 -o $t/exe $t/c.o -Wl,-L$t/x -Wl,-L$t/y -lfoo \
+ -Wl,-search_dylibs_first
+$t/exe | grep -q Howdy
+
+echo OK