[pypy-commit] pypy release-5.x: advancing the pointer to correctly return the value written from libffi, the reason why this does not happen on e.g. ppc bigendian 64 bit is: libffi ppc casts the return value to the requested type (s390x does not and we have discussed this enough already)

[plan_rich]

Author: Richard Plangger <planri...@gmail.com>
Branch: release-5.x
Changeset: r83396:9d2afadd0b72
Date: 2016-01-21 20:37 +0100
http://bitbucket.org/pypy/pypy/changeset/9d2afadd0b72/

Log:    advancing the pointer to correctly return the value written from
        libffi, the reason why this does not happen on e.g. ppc bigendian 64
        bit is: libffi ppc casts the return value to the requested type
        (s390x does not and we have discussed this enough already) (grafted
        from 08606f22af4a38ecf9d4b5cb2207c5f0b3b32766)

diff --git a/pypy/module/_rawffi/interp_rawffi.py 
b/pypy/module/_rawffi/interp_rawffi.py
--- a/pypy/module/_rawffi/interp_rawffi.py
+++ b/pypy/module/_rawffi/interp_rawffi.py
@@ -1,8 +1,10 @@
+import sys
 from pypy.interpreter.baseobjspace import W_Root
 from pypy.interpreter.error import OperationError, oefmt, wrap_oserror
 from pypy.interpreter.gateway import interp2app, unwrap_spec
 from pypy.interpreter.typedef import TypeDef, GetSetProperty
 
+from rpython.jit.backend.llsupport.symbolic import WORD
 from rpython.rlib.clibffi import *
 from rpython.rtyper.lltypesystem import lltype, rffi
 from rpython.rtyper.tool import rffi_platform
@@ -19,6 +21,8 @@
 from pypy.module._rawffi.buffer import RawFFIBuffer
 from pypy.module._rawffi.tracker import tracker
 
+BIGENDIAN = sys.byteorder == 'big'
+
 TYPEMAP = {
     # XXX A mess with unsigned/signed/normal chars :-/
     'c' : ffi_type_uchar,
@@ -331,10 +335,14 @@
             if tracker.DO_TRACING:
                 ll_buf = rffi.cast(lltype.Signed, self.ll_buffer)
                 tracker.trace_allocation(ll_buf, self)
+        self._ll_buffer = self.ll_buffer
 
     def getbuffer(self, space):
         return space.wrap(rffi.cast(lltype.Unsigned, self.ll_buffer))
 
+    def buffer_advance(self, n):
+        self.ll_buffer = rffi.ptradd(self.ll_buffer, n)
+
     def byptr(self, space):
         from pypy.module._rawffi.array import ARRAY_OF_PTRS
         array = ARRAY_OF_PTRS.allocate(space, 1)
@@ -342,16 +350,17 @@
         return space.wrap(array)
 
     def free(self, space):
-        if not self.ll_buffer:
+        if not self._ll_buffer:
             raise segfault_exception(space, "freeing NULL pointer")
         self._free()
 
     def _free(self):
         if tracker.DO_TRACING:
-            ll_buf = rffi.cast(lltype.Signed, self.ll_buffer)
+            ll_buf = rffi.cast(lltype.Signed, self._ll_buffer)
             tracker.trace_free(ll_buf)
-        lltype.free(self.ll_buffer, flavor='raw')
+        lltype.free(self._ll_buffer, flavor='raw')
         self.ll_buffer = lltype.nullptr(rffi.VOIDP.TO)
+        self._ll_buffer = self.ll_buffer
 
     def buffer_w(self, space, flags):
         return RawFFIBuffer(self)
@@ -497,6 +506,11 @@
                 result = self.resshape.allocate(space, 1, autofree=True)
                 # adjust_return_size() was used here on result.ll_buffer
                 self.ptr.call(args_ll, result.ll_buffer)
+                if BIGENDIAN and result.shape.size < WORD:
+                    # we get a 8 byte value in big endian
+                    n = WORD - result.shape.size
+                    result.buffer_advance(n)
+
                 return space.wrap(result)
             else:
                 self.ptr.call(args_ll, lltype.nullptr(rffi.VOIDP.TO))
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