Use -O1 when compiling internal C-Blosc sources. Fixes #110.

RELEASE_NOTES.rst

@@ -13,8 +13,11 @@
 Changes from 1.3.0 to 1.3.1
 ===========================
 
-- Added a protection to avoid using BITSHUFLE with C-Blosc < 1.8.0.
+- Use the -O1 flag for compiling the included C-Blosc sources.  This
+  represents slower performance, but fixes the nasty issue #110.  Also,
+  it prints a warning for using an external C-Blosc library.
 
+- Added a protection to avoid using BITSHUFLE with C-Blosc < 1.8.0.
 
 - Restored old symbols for backward compatibility with pre 1.3.0:
     BLOSC_VERSION_STRING

setup.py

@@ -9,6 +9,8 @@
 
 # flake8: noqa
 
+from __future__ import print_function
+
 import os
 import platform
 import re
@@ -78,8 +80,13 @@ def exit_with_error(message):
     inc_dirs += [os.path.join(BLOSC_DIR, 'include')]
     libs += ['blosc']
 else:
-    # Compiling everything from sources
-    # Blosc + BloscLZ sources
+    # Compiling everything from included C-Blosc sources
+    print("*******************************************************\n"
+          "**Warning:** Compiling with included C-Blosc sources.  \n"
+          "For performance reasons, consider to use the --blosc   \n"
+          "flag for passing an external C-Blosc library location. \n"
+          "*******************************************************\n")
+    # Warn about the convenience to use the shared library
     # We still have to figure out how to detect AVX2 in Python,
     # so no AVX2 support for the time being
     sources += [f for f in glob.glob('c-blosc/blosc/*.c') if 'avx2' not in f]
@@ -94,19 +101,25 @@ def exit_with_error(message):
     inc_dirs += glob.glob('c-blosc/internal-complibs/*')
     # ...and the macros for all the compressors supported
     def_macros += [('HAVE_LZ4', 1), ('HAVE_SNAPPY', 1), ('HAVE_ZLIB', 1)]
-    if os.name == 'nt':
+
+    if platform.system() == "Linux":
+        # Compiling with more than -O2 can cause segfaults; see:
+        # https://github.com/Blosc/python-blosc/issues/110
+        CFLAGS.append('-O1')
+
+    if os.name == 'posix':
+        if re.match("i.86", platform.machine()) is not None:
+            # Add -msse2 flag for optimizing shuffle in Blosc
+            # (only necessary for 32-bit Intel architectures)
+            CFLAGS.append("-msse2")
+    elif os.name == 'nt':
         # Windows always should have support for SSE2
         # (present in all x86/amd64 architectures since 2003)
         def_macros += [('__SSE2__', 1)]
 
-if os.name == 'posix':
     if re.match("i.86|x86", platform.machine()) is not None:
         # Always enable SSE2 for AMD/Intel machines
-        CFLAGS.append('-DSHUFFLE_SSE2_ENABLED')
-    if re.match("i.86", platform.machine()) is not None:
-        # Add -msse2 flag for optimizing shuffle in Blosc
-        # (only necessary for 32-bit Intel architectures)
-        CFLAGS.append("-msse2")
+        def_macros += [('SHUFFLE_SSE2_ENABLED', 1)]
 
 classifiers = """\
 Development Status :: 5 - Production/Stable