[ELF] Skip incompatible files specified by linker script GROUP command

Fixes https://github.com/rui314/mold/issues/260

elf/linker-script.cc

@@ -172,12 +172,12 @@ static MappedFile<Context<E>> *resolve_path(Context<E> &ctx, std::string_view to
   if (str.starts_with("-l"))
     return find_library(ctx, str.substr(2));
 
-  if (MappedFile<Context<E>> *mf = MappedFile<Context<E>>::open(ctx, str))
+  if (MappedFile<Context<E>> *mf = open_library(ctx, str))
     return mf;
 
   for (std::string_view dir : ctx.arg.library_paths) {
     std::string path = std::string(dir) + "/" + str;
-    if (MappedFile<Context<E>> *mf = MappedFile<Context<E>>::open(ctx, path))
+    if (MappedFile<Context<E>> *mf = open_library(ctx, path))
       return mf;
   }
 

elf/main.cc

@@ -159,7 +159,7 @@ deduce_machine_type(Context<E> &ctx, std::span<std::string_view> args) {
 }
 
 template <typename E>
-static MappedFile<Context<E>> *open_library(Context<E> &ctx, std::string path) {
+MappedFile<Context<E>> *open_library(Context<E> &ctx, std::string path) {
   MappedFile<Context<E>> *mf = MappedFile<Context<E>>::open(ctx, path);
   if (!mf)
     return nullptr;

elf/mold.h

@@ -1438,6 +1438,9 @@ struct Context {
   Symbol<E> *etext = nullptr;
 };
 
+template <typename E>
+MappedFile<Context<E>> *open_library(Context<E> &ctx, std::string path);
+
 template <typename E>
 MappedFile<Context<E>> *find_library(Context<E> &ctx, std::string path);
 

test/elf/incompatible-libs2.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+export LANG=
+set -e
+CC="${CC:-cc}"
+CXX="${CXX:-c++}"
+testname=$(basename -s .sh "$0")
+echo -n "Testing $testname ... "
+cd "$(dirname "$0")"/../..
+mold="$(pwd)/mold"
+t=out/test/elf/$testname
+mkdir -p $t
+
+echo 'int main() {}' | $CC -m32 -o $t/exe -xc - >& /dev/null \
+  || { echo skipped; exit; }
+
+cat <<EOF | $CC -m32 -c -o $t/a.o -xc -
+char hello[] = "Hello world";
+EOF
+
+mkdir -p $t/lib32
+$CC -m32 -shared -o $t/lib32/libfoo.so $t/a.o
+
+cat <<EOF | $CC -c -o $t/d.o -xc -
+char hello[] = "Hello world";
+EOF
+
+mkdir -p $t/lib64
+$CC -shared -o $t/lib64/libfoo.so $t/d.o
+
+cat <<EOF | $CC -c -o $t/e.o -xc -
+#include <stdio.h>
+
+extern char hello[];
+
+int main() {
+  printf("%s\n", hello);
+}
+EOF
+
+mkdir -p $t/script
+echo 'GROUP(libfoo.so)' > $t/script/libfoo.so
+
+$CC -B. -o $t/exe -L$t/lib32 -L$t/lib64 -lfoo $t/e.o -Wl,-rpath $t/lib64 \
+  >& $t/log
+
+grep -q 'lib32/libfoo.so: skipping incompatible file' $t/log
+$t/exe | grep -q 'Hello world'
+
+echo OK