From e056d880e7faa1fba41d9342cf71c9dbcf3e128e Mon Sep 17 00:00:00 2001
From: Karuboniru <yanqiyu01@gmail.com>
Date: Mon, 21 Oct 2024 21:39:05 +0800
Subject: [PATCH] increase file limit when hit the ulimit

---
 lib/mapped-file-unix.cc | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/lib/mapped-file-unix.cc b/lib/mapped-file-unix.cc
index 918e6c5dc3..121a4f2fac 100644
--- a/lib/mapped-file-unix.cc
+++ b/lib/mapped-file-unix.cc
@@ -1,9 +1,21 @@
 #include "common.h"
 
+// for getrlimit, setrlimit
+#include <sys/resource.h>
+
 namespace mold {
 
 MappedFile *open_file_impl(const std::string &path, std::string &error) {
   i64 fd = ::open(path.c_str(), O_RDONLY);
+  // increase rlimit when EMFILE. This is required for llvm lto, since llvm
+  // plugin requires keeping input files open
+  if (fd == -1 && errno == EMFILE) {
+    if (struct rlimit rlim{}; getrlimit(RLIMIT_NOFILE, &rlim) == 0) {
+      rlim.rlim_cur = rlim.rlim_max;
+      setrlimit(RLIMIT_NOFILE, &rlim);
+      fd = ::open(path.c_str(), O_RDONLY);
+    }
+  }
   if (fd == -1) {
     if (errno != ENOENT)
       error = "opening " + path + " failed: " + errno_string();