From 02e740c90dcd368f8de9db00ca34ac4923ffc0e6 Mon Sep 17 00:00:00 2001
From: mintsuki <mintsuki@protonmail.com>
Date: Sat, 28 Sep 2019 11:54:38 +0200
Subject: [PATCH] elf/startup: Add __mlibc_run_constructors() function for
 static linking

---
 options/elf/generic/startup.cpp         | 24 ++++++++++++++++++++++++
 options/elf/include/mlibc/elf/startup.h |  2 ++
 2 files changed, 26 insertions(+)

diff --git a/options/elf/generic/startup.cpp b/options/elf/generic/startup.cpp
index 66ff3e5c..c1c4e2e0 100644
--- a/options/elf/generic/startup.cpp
+++ b/options/elf/generic/startup.cpp
@@ -6,6 +6,30 @@
 #include <bits/ensure.h>
 #include <mlibc/elf/startup.h>
 
+extern "C" size_t __init_array_start[];
+extern "C" size_t __init_array_end[];
+
+static int constructors_ran_already = 0;
+
+struct global_constructor_guard {
+    global_constructor_guard() {
+        constructors_ran_already = 1;
+    }
+};
+
+static global_constructor_guard g;
+
+void __mlibc_run_constructors() {
+    if (!constructors_ran_already) {
+        size_t constructor_count = (size_t)__init_array_end - (size_t)__init_array_start;
+        constructor_count /= sizeof(void*);
+        for (size_t i = 0; i < constructor_count; i++) {
+            void (*ptr)(void) = (void(*)(void))(__init_array_start[i]);
+            ptr();
+        }
+    }
+}
+
 namespace mlibc {
 
 void parse_exec_stack(void *opaque_sp, exec_stack_data *data) {
diff --git a/options/elf/include/mlibc/elf/startup.h b/options/elf/include/mlibc/elf/startup.h
index cf29d966..728422b0 100644
--- a/options/elf/include/mlibc/elf/startup.h
+++ b/options/elf/include/mlibc/elf/startup.h
@@ -1,6 +1,8 @@
 #ifndef MLIBC_ELF_STARTUP
 #define MLIBC_ELF_STARTUP
 
+void __mlibc_run_constructors();
+
 namespace mlibc {
 
 struct exec_stack_data {