From 55c206216ea93bd84de8f68b81fd903724006b50 Mon Sep 17 00:00:00 2001
From: Alon Zakai <azakai@google.com>
Date: Mon, 26 Feb 2024 17:13:25 -0800
Subject: [PATCH] [Emscripten port] Fix core count logic for
 Emscripten+pthreads (#6350)

Before this all Emscripten builds would use 1 core, but it is important to
allow pthreads builds there to use more.
---
 src/support/threads.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/support/threads.cpp b/src/support/threads.cpp
index e61769a849b..58aa05be481 100644
--- a/src/support/threads.cpp
+++ b/src/support/threads.cpp
@@ -139,15 +139,17 @@ void ThreadPool::initialize(size_t num) {
 }
 
 size_t ThreadPool::getNumCores() {
-#ifdef __EMSCRIPTEN__
+#if defined(__EMSCRIPTEN__) && !defined(__EMSCRIPTEN_PTHREADS__)
+  // In an Emscripten build without pthreads support, avoid the overhead of
+  // including support code for the below runtime checks.
   return 1;
-#else
+#endif
+
   size_t num = std::max(1U, std::thread::hardware_concurrency());
   if (getenv("BINARYEN_CORES")) {
     num = std::stoi(getenv("BINARYEN_CORES"));
   }
   return num;
-#endif
 }
 
 ThreadPool* ThreadPool::get() {