Better use of @memoize to avoid caching config flag

theano/tensor/blas.py

@@ -529,20 +529,59 @@ ger = Ger(destructive=False)
 ger_destructive = Ger(destructive=True)
 
 
-@utils.memoize
 def ldflags(libs=True, flags=False, libs_dir=False, include_dir=False):
-    """Return a list of libraries against which an Op's object file should be
-    linked to benefit from a BLAS implementation.
+    """Extract a list of compilation flags from config.blas.ldflags.
+
+    Depending on the options, different type of flags will be kept.
+    It returns a list of libraries against which an Op's object file
+    should be linked to benefit from a BLAS implementation.
+
+    :type libs: bool, defaults to True
+    :param libs: extract flags starting with "-l"
+    :type libs_dir: bool, defaults to False
+    :param libs_dir: extract flags starting with "-L"
+    :type include_dir: bool, defaults to False
+    :param include_dir: extract flags starting with "-I"
+    :type flags: bool, defaults to False
+    :param flags: extract all the other flags
+    :rtype: list of strings
+    :returns: extracted flags
+    """
+    ldflags_str = theano.config.blas.ldflags
+    return _ldflags(ldflags_str=ldflags_str,
+                    libs=libs,
+                    flags=flags,
+                    libs_dir=libs_dir,
+                    include_dir=include_dir)
 
-    Default: ['blas'], but configuration variable config.blas.ldflags
-    overrides this.
+
+@utils.memoize
+def _ldflags(ldflags_str, libs, flags, libs_dir, include_dir):
+    """Extract list of compilation flags from a string.
+
+    Depending on the options, different type of flags will be kept.
+
+    :type ldflags_str: string
+    :param ldflags_str: the string to process. Typically, this will
+        be the content of `theano.config.blas.ldflags`
+    :type libs: bool
+    :param libs: extract flags starting with "-l"
+    :type libs_dir: bool
+    :param libs_dir: extract flags starting with "-L"
+    :type include_dir: bool
+    :param include_dir: extract flags starting with "-I"
+    :type flags: bool
+    :param flags: extract all the other flags
+    :rtype: list of strings
+    :returns: extracted flags
     """
     rval = []
     if libs_dir:
         found_dyn = False
-        dirs = [x[2:] for x in config.blas.ldflags.split()
+        dirs = [x[2:] for x in ldflags_str.split()
                 if x.startswith('-L')]
-        l = ldflags()
+        l = _ldflags(ldflags_str=ldflags_str, libs=True,
+                     flags=False, libs_dir=False, include_dir=False)
         for d in dirs:
             for f in os.listdir(d):
                 if (f.endswith('.so') or f.endswith('.dylib') or
@@ -554,7 +593,7 @@ def ldflags(libs=True, flags=False, libs_dir=False, include_dir=False):
                     "library_dir of the library we use for blas. If you use "
                     "ATLAS, make sure to compile it with dynamics library.")
 
-    for t in config.blas.ldflags.split():
+    for t in ldflags_str.split():
         # Remove extra quote.
         if t.startswith("'") or t.startswith('"'):
             t = t[1:]
@@ -565,7 +604,8 @@ def ldflags(libs=True, flags=False, libs_dir=False, include_dir=False):
             t0, t1, t2 = t[0:3]
             assert t0 == '-'
         except Exception:
-            raise ValueError('invalid token in config.blas.ldflags', t)
+            raise ValueError('invalid token "%s" in ldflags_str: "%s"'
+                             % (t, ldflags_str))
         if libs_dir and t1 == 'L':
             rval.append(t[2:])
         elif include_dir and t1 == 'I':