[pypy-commit] pypy default: Fix for rgc.move_out_of_nursery() in very old GCs like "semispace"

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r89538:df8618e832de
Date: 2017-01-13 12:55 +0100
http://bitbucket.org/pypy/pypy/changeset/df8618e832de/

Log:	Fix for rgc.move_out_of_nursery() in very old GCs like "semispace"

diff --git a/rpython/memory/gctransform/framework.py b/rpython/memory/gctransform/framework.py
--- a/rpython/memory/gctransform/framework.py
+++ b/rpython/memory/gctransform/framework.py
@@ -1601,6 +1601,8 @@
                                       resulttype=llmemory.Address)
             hop.genop("cast_adr_to_ptr", [v_ret],
                       resultvar = hop.spaceop.result)
+        else:
+            hop.rename("same_as")
 
 
 
diff --git a/rpython/rlib/buffer.py b/rpython/rlib/buffer.py
--- a/rpython/rlib/buffer.py
+++ b/rpython/rlib/buffer.py
@@ -112,6 +112,7 @@
 
     def get_raw_address(self):
         from rpython.rtyper.lltypesystem import rffi
+        # may still raise ValueError on some GCs
         return rffi.get_raw_address_of_string(self.value)
 
 class SubBuffer(Buffer):
diff --git a/rpython/rlib/rgc.py b/rpython/rlib/rgc.py
--- a/rpython/rlib/rgc.py
+++ b/rpython/rlib/rgc.py
@@ -542,8 +542,13 @@
         become identical to the one returned.
 
         NOTE: Only use for immutable objects!
+
+        NOTE: Might fail on some GCs!  You have to check again
+        can_move() afterwards.  It should always work with the default
+        GC.  With Boehm, can_move() is always False so
+        move_out_of_nursery() should never be called in the first place.
     """
-    pass
+    return obj
 
 class MoveOutOfNurseryEntry(ExtRegistryEntry):
     _about_ = move_out_of_nursery
diff --git a/rpython/rtyper/lltypesystem/rffi.py b/rpython/rtyper/lltypesystem/rffi.py
--- a/rpython/rtyper/lltypesystem/rffi.py
+++ b/rpython/rtyper/lltypesystem/rffi.py
@@ -1336,6 +1336,8 @@
     as key is alive. If key goes out of scope, the buffer will eventually
     be freed. `string` cannot go out of scope until the RawBytes object
     referencing it goes out of scope.
+
+    NOTE: may raise ValueError on some GCs, but not the default one.
     """
     assert isinstance(string, str)
     from rpython.rtyper.annlowlevel import llstr
@@ -1346,6 +1348,8 @@
     if we_are_translated():
         if rgc.can_move(string):
             string = rgc.move_out_of_nursery(string)
+            if rgc.can_move(string):
+                raise ValueError("cannot make string immovable")
 
         # string cannot move now! return the address
         lldata = llstr(string)
diff --git a/rpython/rtyper/lltypesystem/test/test_ztranslated.py b/rpython/rtyper/lltypesystem/test/test_ztranslated.py
--- a/rpython/rtyper/lltypesystem/test/test_ztranslated.py
+++ b/rpython/rtyper/lltypesystem/test/test_ztranslated.py
@@ -37,7 +37,10 @@
     return ptr
 
 def main(argv=[]):
-    use_str()
+    try:
+        use_str()
+    except ValueError:
+        return 42
     gc.collect()
     mystr = b"12341234aa"*4096*10
     #debug_assert(not rgc.can_move(mystr), "long string can move... why?")
@@ -56,4 +59,15 @@
 
 def test_compiled_incminimark():
     fn = compile(main, [], gcpolicy="incminimark")
-    fn()
+    res = fn()
+    assert res == 0
+
+def test_compiled_semispace():
+    fn = compile(main, [], gcpolicy="semispace")
+    res = fn()
+    assert res == 42    # get_raw_address_of_string() raises ValueError
+
+def test_compiled_boehm():
+    fn = compile(main, [], gcpolicy="boehm")
+    res = fn()
+    assert res == 0