From 01b55b48f7c121e96b2e0383755089e0795253de Mon Sep 17 00:00:00 2001
From: Mark Wiebe <mwwiebe@gmail.com>
Date: Wed, 29 Aug 2012 13:51:07 -0700
Subject: [PATCH] Add detection of whether LLVM has PTX in the windows build

---
 llvm-config-win32.py | 10 ++++++++--
 llvm/extra.h         |  5 -----
 setup.py             | 18 ++++++++++++++----
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/llvm-config-win32.py b/llvm-config-win32.py
index db9de65..0e70231 100644
--- a/llvm-config-win32.py
+++ b/llvm-config-win32.py
@@ -1,8 +1,8 @@
 import sys, os
 
-def find_path_of(filename):
+def find_path_of(filename, envvar='PATH'):
     """Finds the path from $PATH where the file exists, returns None if not found."""
-    pathlist = os.getenv('PATH').split(os.pathsep)
+    pathlist = os.getenv(envvar).split(os.pathsep)
     for path in pathlist:
         if os.path.exists(os.path.join(path, filename)):
             return os.path.abspath(path)
@@ -50,6 +50,12 @@ Advapi32
 Shell32
 """.split():
         print('-l%s' % lib)
+        # Look for the PTX .lib in %LIBPATH%
+        if find_path_of('LLVMPTXCodeGen.lib', 'LIBPATH') != None:
+            print('-lLLVMPTXAsmPrinter')
+            print('-lLLVMPTXCodeGen')
+            print('-lLLVMPTXDesc')
+            print('-lLLVMPTXInfo')
 elif sys.argv[1] == '--includedir': 
     llvmbin = find_path_of('llvm-tblgen.exe')
     if llvmbin is None:
diff --git a/llvm/extra.h b/llvm/extra.h
index 7182411..4cc3072 100644
--- a/llvm/extra.h
+++ b/llvm/extra.h
@@ -45,15 +45,10 @@
     #define LLVM_HAS_NVPTX 0
 #endif
 
-#if defined(_WIN32)
-    #define LLVM_DISABLE_PTX
-#endif
-
 #include "llvm-c/Transforms/PassManagerBuilder.h"
 
 #include "llvm_c_extra.h"
 
-
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/setup.py b/setup.py
index 611472a..219c8da 100644
--- a/setup.py
+++ b/setup.py
@@ -68,7 +68,10 @@ if dynlink:
     objs_core = []
 else:
     if sys.platform == 'win32':
-        print('PTX is disabled on Win32 at the moment')
+        # XXX: If found, the PTX components are returned by llvm-config-win32.py,
+        #      regardless of whether we ask for them. There should be a better way
+        #      eventually.
+        print('PTX is included on Win32 at if found by llvm-config-win32.py')
         ptx_components = []
     elif llvm_version <= (3, 1): # select between PTX & NVPTX
         print('Using PTX')
@@ -91,13 +94,20 @@ else:
          'asmparser', 'linker', 'support', 'vectorize']
         + ptx_components)
 
+macros = [('__STDC_CONSTANT_MACROS', None),
+          ('__STDC_LIMIT_MACROS', None)]
+if sys.platform == 'win32':
+    # If no PTX lib got added, disable PTX in the build
+    if 'LLVMPTXCodeGen' not in libs_core:
+        macros.append(('LLVM_DISABLE_PTX', None)),
+else:
+    macros.append(('_GNU_SOURCE', None))
+
 extra_link_args = ldflags.split()
 kwds = dict(ext_modules = [Extension(
     name='llvm._core',
     sources=['llvm/_core.cpp', 'llvm/wrap.cpp', 'llvm/extra.cpp'],
-    define_macros = [('__STDC_CONSTANT_MACROS', None),
-                     ('__STDC_LIMIT_MACROS', None),
-                     ('_GNU_SOURCE', None)],
+    define_macros = macros,
     include_dirs = ['/usr/include', incdir],
     library_dirs = [libdir],
     libraries = libs_core,