Add -push-state and -pop-state

commandline.cc

@@ -379,6 +379,10 @@ void parse_nonpositional_args(std::span<std::string_view> args,
       remaining.push_back(arg);
     } else if (read_arg(args, arg, "script") || read_arg(args, arg, "T")) {
       remaining.push_back(arg);
+    } else if (read_flag(args, "push-state")) {
+      remaining.push_back("-push-state");
+    } else if (read_flag(args, "pop-state")) {
+      remaining.push_back("-pop-state");
     } else {
       if (args[0][0] == '-')
         Fatal() << "mold: unknown command line option: " << args[0];

main.cc

@@ -934,6 +934,8 @@ MemoryMappedFile *find_library(std::string name,
 
 static void read_input_files(std::span<std::string_view> args,
                              ReadContext &ctx) {
+  std::vector<std::tuple<bool, bool>> state;
+
   while (!args.empty()) {
     std::string_view arg;
 
@@ -945,6 +947,13 @@ static void read_input_files(std::span<std::string_view> args,
       ctx.whole_archive = true;
     } else if (read_flag(args, "no-whole-archive")) {
       ctx.whole_archive = false;
+    } else if (read_flag(args, "push-state")) {
+      state.push_back({ctx.as_needed, ctx.whole_archive});
+    } else if (read_flag(args, "pop-state")) {
+      if (state.empty())
+        Fatal() << "no state pushed before popping";
+      std::tie(ctx.as_needed, ctx.whole_archive) = state.back();
+      state.pop_back();
     } else if (read_arg(args, arg, "l")) {
       read_file(find_library(std::string(arg), config.library_paths), ctx);
     } else {

test/push-pop-state.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+set -e
+cd $(dirname $0)
+echo -n "Testing $(basename -s .sh $0) ... "
+t=$(pwd)/tmp/$(basename -s .sh $0)
+mkdir -p $t
+
+cat <<EOF | clang -shared -o $t/a.so -xc -
+int foo = 1;
+EOF
+
+cat <<EOF | clang -shared -o $t/b.so -xc -
+int bar = 1;
+EOF
+
+cat <<EOF | clang -c -o $t/c.o -xc -
+int main() {}
+EOF
+
+clang -fuse-ld=`pwd`/../mold -o $t/exe $t/c.o -Wl,-as-needed \
+  -Wl,-push-state -Wl,-no-as-needed $t/a.so -Wl,-pop-state $t/b.so
+
+readelf --dynamic $t/exe > $t/log
+fgrep -q a.so $t/log
+! fgrep -q b.so $t/log
+
+echo OK