From 6ffc0fd601de20a961367357f74295902d7c7869 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dani=C3=ABl=20de=20Kok?= <me@danieldk.eu>
Date: Wed, 5 Aug 2020 20:51:05 +0200
Subject: [PATCH] python3Packages.pytorch: fix Darwin build by disabling GCD

PyTorch 1.6.0 has updated the vendored pthreadpool library, which has recently
added support for Grand Central Dispatch. Unfortunately, it uses functionality
(DISPATCH_APPLY_AUTO) that is only available since macOS 10.13, whereas we are
still using 10.12 libraries.

We can't directly pass through option to vendored libraries, since the setup.py
scripts creates/filters the options that are passed to CMake. So, instead, this
adds a small patch that disables the GCD functionality in pthreadpool.
---
 .../python-modules/pytorch/default.nix        |  7 +++
 .../pytorch/pthreadpool-disable-gcd.diff      | 45 +++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 pkgs/development/python-modules/pytorch/pthreadpool-disable-gcd.diff

diff --git a/pkgs/development/python-modules/pytorch/default.nix b/pkgs/development/python-modules/pytorch/default.nix
index 4eabaf26f772..da7da4ca38fc 100644
--- a/pkgs/development/python-modules/pytorch/default.nix
+++ b/pkgs/development/python-modules/pytorch/default.nix
@@ -135,6 +135,13 @@ in buildPythonPackage rec {
       url = "https://github.com/pytorch/pytorch/commit/7676682584d0caf9243bce74ea0a88711ec4a807.diff";
       sha256 = "13spncaqlpsp8qk2850yly7xqwmhhfwznhmzkk8jgpslkbx75vgq";
     })
+  ] ++ lib.optionals stdenv.isDarwin [
+    # pthreadpool added support for Grand Central Dispatch in April
+    # 2020. However, this relies on functionality (DISPATCH_APPLY_AUTO)
+    # that is available starting with macOS 10.13. However, our current
+    # base is 10.12. Until we upgrade, we can fall back on the older
+    # pthread support.
+    ./pthreadpool-disable-gcd.diff
   ];
 
   preConfigure = lib.optionalString cudaSupport ''
diff --git a/pkgs/development/python-modules/pytorch/pthreadpool-disable-gcd.diff b/pkgs/development/python-modules/pytorch/pthreadpool-disable-gcd.diff
new file mode 100644
index 000000000000..eddd45723f8b
--- /dev/null
+++ b/pkgs/development/python-modules/pytorch/pthreadpool-disable-gcd.diff
@@ -0,0 +1,45 @@
+diff --git a/third_party/pthreadpool/CMakeLists.txt b/third_party/pthreadpool/CMakeLists.txt
+index 0db3264..1ba91c4 100644
+--- a/third_party/pthreadpool/CMakeLists.txt
++++ b/third_party/pthreadpool/CMakeLists.txt
+@@ -74,9 +74,7 @@ IF(EMSCRIPTEN)
+   LIST(APPEND PTHREADPOOL_SRCS src/shim.c)
+ ELSE()
+   LIST(APPEND PTHREADPOOL_SRCS src/portable-api.c src/memory.c)
+-  IF(APPLE AND (PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "default" OR PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "gcd"))
+-    LIST(APPEND PTHREADPOOL_SRCS src/gcd.c)
+-  ELSEIF(CMAKE_SYSTEM_NAME MATCHES "^(Windows|CYGWIN|MSYS)$" AND (PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "default" OR PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "event"))
++  IF(CMAKE_SYSTEM_NAME MATCHES "^(Windows|CYGWIN|MSYS)$" AND (PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "default" OR PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "event"))
+     LIST(APPEND PTHREADPOOL_SRCS src/windows.c)
+   ELSE()
+     LIST(APPEND PTHREADPOOL_SRCS src/pthreads.c)
+@@ -111,10 +109,6 @@ ELSEIF(PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "futex")
+   TARGET_COMPILE_DEFINITIONS(pthreadpool PRIVATE PTHREADPOOL_USE_FUTEX=1)
+   TARGET_COMPILE_DEFINITIONS(pthreadpool PRIVATE PTHREADPOOL_USE_GCD=0)
+   TARGET_COMPILE_DEFINITIONS(pthreadpool PRIVATE PTHREADPOOL_USE_EVENT=0)
+-ELSEIF(PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "gcd")
+-  TARGET_COMPILE_DEFINITIONS(pthreadpool PRIVATE PTHREADPOOL_USE_FUTEX=0)
+-  TARGET_COMPILE_DEFINITIONS(pthreadpool PRIVATE PTHREADPOOL_USE_GCD=1)
+-  TARGET_COMPILE_DEFINITIONS(pthreadpool PRIVATE PTHREADPOOL_USE_EVENT=0)
+ ELSEIF(PTHREADPOOL_SYNC_PRIMITIVE STREQUAL "event")
+   TARGET_COMPILE_DEFINITIONS(pthreadpool PRIVATE PTHREADPOOL_USE_FUTEX=0)
+   TARGET_COMPILE_DEFINITIONS(pthreadpool PRIVATE PTHREADPOOL_USE_GCD=0)
+diff --git a/third_party/pthreadpool/src/threadpool-common.h b/third_party/pthreadpool/src/threadpool-common.h
+index ca84744..244d0ca 100644
+--- a/third_party/pthreadpool/src/threadpool-common.h
++++ b/third_party/pthreadpool/src/threadpool-common.h
+@@ -14,14 +14,6 @@
+ 	#endif
+ #endif
+ 
+-#ifndef PTHREADPOOL_USE_GCD
+-	#if defined(__APPLE__)
+-		#define PTHREADPOOL_USE_GCD 1
+-	#else
+-		#define PTHREADPOOL_USE_GCD 0
+-	#endif
+-#endif
+-
+ #ifndef PTHREADPOOL_USE_EVENT
+ 	#if defined(_WIN32) || defined(__CYGWIN__)
+ 		#define PTHREADPOOL_USE_EVENT 1