From 5c96192c196c3a43f43de26c8256ed9a784f5140 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Wed, 24 Jul 2024 17:38:54 +0200
Subject: [PATCH] start: Add a comment explaining our paranoid stance on ABI
 guarantees.

---
 lib/std/start.zig | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/std/start.zig b/lib/std/start.zig
index 9d4edd16bf..21baacc764 100644
--- a/lib/std/start.zig
+++ b/lib/std/start.zig
@@ -272,6 +272,12 @@ fn _start() callconv(.Naked) noreturn {
             : [tos] "={rax}" (-> *std.os.plan9.Tos),
         );
     }
+
+    // Note that we maintain a very low level of trust with regards to ABI guarantees at this point.
+    // We will redundantly align the stack, clear the link register, etc. While e.g. the Linux
+    // kernel is usually good about upholding the ABI guarantees, the same cannot be said of dynamic
+    // linkers; musl's ldso, for example, opts to not align the stack when invoking the dynamic
+    // linker explicitly.
     asm volatile (switch (native_arch) {
             .x86_64 =>
             \\ xorl %%ebp, %%ebp