Merge pull request #13161 from zerothi/linalg-cblas

BLD: streamlined CBLAS linkage tries, default to try libraries *as-is*

1 files changed, 40 insertions, 20 deletions

diff --git a/numpy/distutils/system_info.py b/numpy/distutils/system_info.py
index 4d923ad26..8a42434ff 100644
--- a/numpy/distutils/system_info.py
+++ b/numpy/distutils/system_info.py
@@ -1689,23 +1689,46 @@ class blas_info(system_info):
         else:
             info['include_dirs'] = self.get_include_dirs()
         if platform.system() == 'Windows':
-            # The check for windows is needed because has_cblas uses the
+            # The check for windows is needed because get_cblas_libs uses the
             # same compiler that was used to compile Python and msvc is
             # often not installed when mingw is being used. This rough
             # treatment is not desirable, but windows is tricky.
             info['language'] = 'f77'  # XXX: is it generally true?
         else:
-            lib = self.has_cblas(info)
+            lib = self.get_cblas_libs(info)
             if lib is not None:
                 info['language'] = 'c'
-                info['libraries'] = [lib]
+                info['libraries'] = lib
                 info['define_macros'] = [('HAVE_CBLAS', None)]
         self.set_info(**info)
 
-    def has_cblas(self, info):
+    def get_cblas_libs(self, info):
+        """ Check whether we can link with CBLAS interface
+
+        This method will search through several combinations of libraries
+        to check whether CBLAS is present:
+
+        1. Libraries in ``info['libraries']``, as is
+        2. As 1. but also explicitly adding ``'cblas'`` as a library
+        3. As 1. but also explicitly adding ``'blas'`` as a library
+        4. Check only library ``'cblas'``
+        5. Check only library ``'blas'``
+
+        Parameters
+        ----------
+        info : dict
+           system information dictionary for compilation and linking
+
+        Returns
+        -------
+        libraries : list of str or None
+            a list of libraries that enables the use of CBLAS interface.
+            Returns None if not found or a compilation error occurs.
+
+            Since 1.17 returns a list.
+        """
         # primitive cblas check by looking for the header and trying to link
         # cblas or blas
-        res = False
         c = customized_ccompiler()
         tmpdir = tempfile.mkdtemp()
         s = """#include <cblas.h>
@@ -1724,29 +1747,26 @@ class blas_info(system_info):
                 # check we can compile (find headers)
                 obj = c.compile([src], output_dir=tmpdir,
                                 include_dirs=self.get_include_dirs())
+            except (distutils.ccompiler.CompileError, distutils.ccompiler.LinkError):
+                return None
 
-                # check we can link (find library)
-                # some systems have separate cblas and blas libs. First
-                # check for cblas lib, and if not present check for blas lib.
+            # check we can link (find library)
+            # some systems have separate cblas and blas libs.
+            for libs in [info['libraries'], ['cblas'] + info['libraries'],
+                         ['blas'] + info['libraries'], ['cblas'], ['blas']]:
                 try:
                     c.link_executable(obj, os.path.join(tmpdir, "a.out"),
-                                      libraries=["cblas"],
+                                      libraries=libs,
                                       library_dirs=info['library_dirs'],
                                       extra_postargs=info.get('extra_link_args', []))
-                    res = "cblas"
+                    return libs
+                    # This breaks the for loop
+                    break
                 except distutils.ccompiler.LinkError:
-                    c.link_executable(obj, os.path.join(tmpdir, "a.out"),
-                                      libraries=["blas"],
-                                      library_dirs=info['library_dirs'],
-                                      extra_postargs=info.get('extra_link_args', []))
-                    res = "blas"
-            except distutils.ccompiler.CompileError:
-                res = None
-            except distutils.ccompiler.LinkError:
-                res = None
+                    pass
         finally:
             shutil.rmtree(tmpdir)
-        return res
+        return None
 
 
 class openblas_info(blas_info):