From f49cc7f3fd3db62448959c0ffbf8a9fe0519efe6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Kochma=C5=84ski?= <daniel@turtleware.eu>
Date: Thu, 27 Mar 2025 14:26:57 +0100
Subject: [PATCH] core: the first environment is statically allocated

This is to avoid circularity between the first environment (and interrupts) and
the garbage collector.
---
 src/c/alloc_2.d  | 23 +++++++++--------------
 src/c/main.d     | 26 ++++++++------------------
 src/h/external.h |  1 +
 3 files changed, 18 insertions(+), 32 deletions(-)

diff --git a/src/c/alloc_2.d b/src/c/alloc_2.d
index c52f8f209..ea44b057c 100644
--- a/src/c/alloc_2.d
+++ b/src/c/alloc_2.d
@@ -1183,22 +1183,17 @@ ecl_mark_env(struct cl_env_struct *env)
 static void
 stacks_scanner()
 {
-  cl_env_ptr the_env = ecl_process_env_unsafe();
-  cl_object l;
-  l = cl_core.libraries;
-  if (l) {
-    for (; l != ECL_NIL; l = ECL_CONS_CDR(l)) {
-      cl_object dll = ECL_CONS_CAR(l);
-      if (dll->cblock.locked) {
-        GC_push_conditional((void *)dll, (void *)(&dll->cblock + 1), 1);
-        GC_set_mark_bit((void *)dll);
-      }
+  cl_object l = cl_core.libraries;
+  loop_for_on_unsafe(l) {
+    cl_object dll = ECL_CONS_CAR(l);
+    if (dll->cblock.locked) {
+      GC_push_conditional((void *)dll, (void *)(&dll->cblock + 1), 1);
+      GC_set_mark_bit((void *)dll);
     }
-  }
+  } end_loop_for_on_unsafe(l);
   GC_push_all((void *)(&cl_core), (void *)(&cl_core + 1));
   GC_push_all((void *)cl_symbols, (void *)(cl_symbols + cl_num_symbols_in_core));
-  if (the_env != NULL)
-    ecl_mark_env(the_env);
+  ecl_mark_env(cl_core.first_env);
 #ifdef ECL_THREADS
   l = cl_core.processes;
   if (l != OBJNULL) {
@@ -1207,7 +1202,7 @@ stacks_scanner()
       cl_object process = l->vector.self.t[i];
       if (!Null(process)) {
         cl_env_ptr env = process->process.env;
-        if (env && (env != the_env)) ecl_mark_env(env);
+        if (env && (env != cl_core.first_env)) ecl_mark_env(env);
       }
     }
   }
diff --git a/src/c/main.d b/src/c/main.d
index e7b48ec53..13915a155 100644
--- a/src/c/main.d
+++ b/src/c/main.d
@@ -48,10 +48,8 @@
 
 /******************************* EXPORTS ******************************/
 
-#if !defined(ECL_THREADS)
-cl_env_ptr cl_env_p = NULL;
-#endif
 const char *ecl_self;
+static struct cl_env_struct first_env;
 
 /************************ GLOBAL INITIALIZATION ***********************/
 
@@ -248,20 +246,13 @@ _ecl_alloc_env(cl_env_ptr parent)
     ecl_internal_error("Unable to allocate environment structure.");
 #else
 # if defined(ECL_USE_GUARD_PAGE)
-  output = VirtualAlloc(0, sizeof(*output), MEM_COMMIT,
-                        PAGE_READWRITE);
+  output = VirtualAlloc(0, sizeof(*output), MEM_COMMIT, PAGE_READWRITE);
   if (output == NULL)
     ecl_internal_error("Unable to allocate environment structure.");
 # else
-  static struct cl_env_struct first_env;
-  if (!ecl_option_values[ECL_OPT_BOOTED]) {
-    /* We have not set up any environment. Hence, we cannot call ecl_alloc()
-     * because it will need to stop interrupts and currently we rely on
-     * the environment for that */
-    output = ecl_alloc_unprotected(sizeof(*output));
-  } else {
-    output = ecl_alloc(sizeof(*output));
-  }
+  output = ecl_alloc(sizeof(*output));
+  if (output == NULL)
+    ecl_internal_error("Unable to allocate environment structure.");
 # endif
 #endif
   {
@@ -270,9 +261,7 @@ _ecl_alloc_env(cl_env_ptr parent)
       output->default_sigmask = 0;
     } else if (parent) {
       output->default_sigmask = ecl_alloc_atomic(bytes);
-      memcpy(output->default_sigmask,
-             parent->default_sigmask,
-             bytes);
+      memcpy(output->default_sigmask, parent->default_sigmask, bytes);
     } else {
       output->default_sigmask = cl_core.default_sigmask;
     }
@@ -414,6 +403,7 @@ struct cl_core_struct cl_core = {
 
   .system_properties = ECL_NIL,
 
+  .first_env = &first_env,
 #ifdef ECL_THREADS
   .processes = ECL_NIL,
 #endif
@@ -501,7 +491,7 @@ cl_boot(int argc, char **argv)
   init_unixint(0);
   init_alloc();
   GC_disable();
-  env = _ecl_alloc_env(0);
+  env = cl_core.first_env;
   init_threads(env);
 
   /*
diff --git a/src/h/external.h b/src/h/external.h
index a4161f577..959970b88 100755
--- a/src/h/external.h
+++ b/src/h/external.h
@@ -221,6 +221,7 @@ struct cl_core_struct {
 
         cl_object system_properties;
 
+        cl_env_ptr first_env;
 #ifdef ECL_THREADS
         cl_object processes;
         ecl_mutex_t processes_lock;