[Mach-O] Add -sectcreate

macho/cmdline.cc

@@ -60,10 +60,11 @@ static const char helpmsg[] = R"(
                               Set platform, platform version and SDK version
   -random_uuid                Generate a random LC_UUID load command
   -rpath <PATH>               Add PATH to the runpath search path list
+  -search_dylibs_first
+  -search_paths_first
+  -sectcreate <SEGNAME> <SECTNAME> <FILE>
   -stack_size <SIZE>
   -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)";
 
@@ -300,14 +301,16 @@ std::vector<std::string> parse_nonpositional_args(Context<E> &ctx) {
       ctx.arg.uuid = UUID_RANDOM;
     } else if (read_arg("-rpath")) {
       ctx.arg.rpath.push_back(std::string(arg));
-    } else if (read_hex("-stack_size")) {
-      ctx.arg.stack_size = hex_arg;
-    } 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_arg3("-sectcreate")) {
+      ctx.arg.sectcreate.push_back({arg, arg2, arg3});
+    } else if (read_hex("-stack_size")) {
+      ctx.arg.stack_size = hex_arg;
+    } else if (read_arg("-syslibroot")) {
+      ctx.arg.syslibroot.push_back(std::string(arg));
     } else if (read_flag("-t")) {
       ctx.arg.trace = true;
     } else if (read_flag("-v")) {

macho/main.cc

@@ -495,6 +495,15 @@ static int do_main(int argc, char **argv) {
     Fatal(ctx) << "unknown cputype: " << ctx.arg.arch;
   }
 
+  // Handle -sectcreate
+  for (SectCreateOption arg : ctx.arg.sectcreate) {
+    MappedFile<Context<E>> *mf =
+      MappedFile<Context<E>>::must_open(ctx, std::string(arg.filename));
+    SectCreateSection<E> *sec =
+      new SectCreateSection<E>(ctx, arg.segname, arg.sectname, mf->get_contents());
+    ctx.chunk_pool.emplace_back(sec);
+  }
+
   read_input_files(ctx, file_args);
 
   for (ObjectFile<E> *file : ctx.objs)

macho/mold.h

@@ -673,6 +673,20 @@ class ThreadPtrsSection : public Chunk<E> {
   std::vector<Symbol<E> *> syms;
 };
 
+template <typename E>
+class SectCreateSection : public Chunk<E> {
+public:
+  SectCreateSection(Context<E> &ctx, std::string_view seg, std::string_view sect,
+                    std::string_view contents)
+    : Chunk<E>(ctx, seg, sect), contents(contents) {
+    this->hdr.size = contents.size();
+  }
+
+  void copy_buf(Context<E> &ctx) override;
+
+  std::string_view contents;
+};
+
 //
 // mapfile.cc
 //
@@ -754,6 +768,12 @@ void do_lto(Context<E> &ctx);
 
 enum UuidKind { UUID_NONE, UUID_HASH, UUID_RANDOM };
 
+struct SectCreateOption {
+  std::string_view segname;
+  std::string_view sectname;
+  std::string_view filename;
+};
+
 template <typename E>
 struct Context {
   Context() {
@@ -820,6 +840,7 @@ struct Context {
     std::vector<std::string> mllvm;
     std::vector<std::string> rpath;
     std::vector<std::string> syslibroot;
+    std::vector<SectCreateOption> sectcreate;
   } arg;
 
   std::vector<std::string_view> cmdline_args;
@@ -846,7 +867,7 @@ struct Context {
   tbb::concurrent_vector<std::unique_ptr<DylibFile<E>>> dylib_pool;
   tbb::concurrent_vector<std::unique_ptr<u8[]>> string_pool;
   tbb::concurrent_vector<std::unique_ptr<MappedFile<Context<E>>>> mf_pool;
-  std::vector<std::unique_ptr<OutputSection<E>>> osec_pool;
+  std::vector<std::unique_ptr<Chunk<E>>> chunk_pool;
 
   tbb::concurrent_vector<std::unique_ptr<TimerRecord>> timer_records;
 

macho/output-chunks.cc

@@ -390,7 +390,7 @@ OutputSection<E>::get_instance(Context<E> &ctx, std::string_view segname,
     return osec;
 
   OutputSection<E> *osec = new OutputSection<E>(ctx, segname, sectname);
-  ctx.osec_pool.emplace_back(osec);
+  ctx.chunk_pool.emplace_back(osec);
   return osec;
 }
 
@@ -1335,6 +1335,11 @@ void ThreadPtrsSection<E>::copy_buf(Context<E> &ctx) {
       buf[i] = sym.get_addr(ctx);
 }
 
+template <typename E>
+void SectCreateSection<E>::copy_buf(Context<E> &ctx) {
+  write_string(ctx.buf + this->hdr.offset, contents);
+}
+
 #define INSTANTIATE(E)                                  \
   template class OutputSegment<E>;                      \
   template class OutputMachHeader<E>;                   \
@@ -1354,7 +1359,8 @@ void ThreadPtrsSection<E>::copy_buf(Context<E> &ctx) {
   template class UnwindInfoSection<E>;                  \
   template class GotSection<E>;                         \
   template class LazySymbolPtrSection<E>;               \
-  template class ThreadPtrsSection<E>
+  template class ThreadPtrsSection<E>;                  \
+  template class SectCreateSection<E>
 
 INSTANTIATE_ALL;
 

test/macho/sectcreate.sh

@@ -0,0 +1,29 @@
+#!/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 -
+int main() {}
+EOF
+
+echo 'foobar' > $t/contents
+
+clang --ld-path=./ld64 -o $t/exe $t/a.o -Wl,-sectcreate,__TEXT,__foo,$t/contents
+
+otool -l $t/exe | grep -A3 'sectname __foo' > $t/log
+grep -q 'segname __TEXT' $t/log
+grep -q 'segname __TEXT' $t/log
+grep -q 'size 0x0*7$' $t/log
+
+echo OK