[pypy-svn] pypy default: Test and fix: fastpath_malloc_varsize() used to not align the request

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r43443:407d02bfd2a7
Date: 2011-04-18 13:54 +0200
http://bitbucket.org/pypy/pypy/changeset/407d02bfd2a7/

Log:	Test and fix: fastpath_malloc_varsize() used to not align the
	request to a multiple of WORD. This gives unaligned nursery
	pointers :-(

diff --git a/pypy/jit/backend/x86/assembler.py b/pypy/jit/backend/x86/assembler.py
--- a/pypy/jit/backend/x86/assembler.py
+++ b/pypy/jit/backend/x86/assembler.py
@@ -2090,6 +2090,7 @@
 
     def malloc_cond(self, nursery_free_adr, nursery_top_adr, size, tid):
         size = max(size, self.cpu.gc_ll_descr.minimal_size_in_nursery)
+        size = (size + WORD-1) & ~(WORD-1)     # round up
         self.mc.MOV(eax, heap(nursery_free_adr))
         self.mc.LEA_rm(edx.value, (eax.value, size))
         self.mc.CMP(edx, heap(nursery_top_adr))

diff --git a/pypy/jit/backend/x86/test/test_gc_integration.py b/pypy/jit/backend/x86/test/test_gc_integration.py
--- a/pypy/jit/backend/x86/test/test_gc_integration.py
+++ b/pypy/jit/backend/x86/test/test_gc_integration.py
@@ -326,6 +326,8 @@
         ARRAY = lltype.GcArray(lltype.Signed)
         arraydescr = cpu.arraydescrof(ARRAY)
         self.arraydescr = arraydescr
+        ARRAYCHAR = lltype.GcArray(lltype.Char)
+        arraychardescr = cpu.arraydescrof(ARRAYCHAR)
 
         self.namespace = locals().copy()
 
@@ -388,3 +390,24 @@
         finish(p0)
         '''
         py.test.raises(Seen, self.interpret, ops, [])
+
+    def test_malloc_array_of_char(self):
+        # check that fastpath_malloc_varsize() respects the alignment
+        # of the pointer in the nursery
+        ops = '''
+        []
+        p1 = new_array(1, descr=arraychardescr)
+        p2 = new_array(2, descr=arraychardescr)
+        p3 = new_array(3, descr=arraychardescr)
+        p4 = new_array(4, descr=arraychardescr)
+        finish(p1, p2, p3, p4)
+        '''
+        self.interpret(ops, [])
+        p1 = self.getptr(0, llmemory.GCREF)
+        p2 = self.getptr(1, llmemory.GCREF)
+        p3 = self.getptr(2, llmemory.GCREF)
+        p4 = self.getptr(3, llmemory.GCREF)
+        assert p1._obj.intval & (WORD-1) == 0    # aligned
+        assert p2._obj.intval & (WORD-1) == 0    # aligned
+        assert p3._obj.intval & (WORD-1) == 0    # aligned
+        assert p4._obj.intval & (WORD-1) == 0    # aligned