From 163f29e51ba656b3a7d275c3e252345878a00958 Mon Sep 17 00:00:00 2001
From: YAMAMOTO Takashi <yamamoto@midokura.com>
Date: Wed, 1 May 2024 16:15:17 +0900
Subject: [PATCH] Add some more comments on WASM_STACK_GUARD_SIZE (#3380)

---
 core/config.h | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/core/config.h b/core/config.h
index 0a77ec94..87427666 100644
--- a/core/config.h
+++ b/core/config.h
@@ -470,8 +470,23 @@
  *     200 bytes (release build, macOS/amd64)
  *     2600 bytes (debug build, macOS/amd64)
  *
- *   libc snprintf (used by eg. wasm_runtime_set_exception) consumes about
- *   1600 bytes stack on macOS/amd64, about 2000 bytes on Ubuntu amd64 20.04.
+ * - platform-provided functions (eg. libc)
+ *
+ *   the following are examples of the stack consumptions observed for
+ *   host APIs.
+ *
+ *   snprintf: (used by eg. wasm_runtime_set_exception)
+ *   - about 1600 bytes on macOS/amd64
+ *   - about 2000 bytes on Ubuntu amd64 20.04
+ *
+ *   gethostbyname:
+ *   - 3KB-6KB on macOS/amd64
+ *   - 10KB on Ubuntu amd64 20.04
+ *
+ *   getaddrinfo:
+ *   - 4KB-17KB on macOS/amd64
+ *   - 12KB on Ubuntu amd64 20.04
+ *   - 0.3-1.5KB on NuttX/esp32s3
  *
  * - stack check wrapper functions generated by the aot compiler
  *   (--stack-bounds-checks=1)
@@ -480,6 +495,9 @@
  *   "precheck functions themselves consume relatively large amount of stack"
  *   when it detects wrapper functions requiring more than 1KB.
  *
+ * - the ABI-defined red zone. eg. 128 bytes for SYSV x86-64 ABI.
+ *   cf. https://en.wikipedia.org/wiki/Red_zone_(computing)
+ *
  * Note: on platforms with lazy function binding, don't forget to consider
  * the symbol resolution overhead on the first call. For example,
  * on Ubuntu amd64 20.04, it seems to consume about 1500 bytes.