Author: Armin Rigo <[email protected]>
Branch: shadowstack-perf-2
Changeset: r84381:94fec9f874f1
Date: 2016-05-11 18:18 +0200
http://bitbucket.org/pypy/pypy/changeset/94fec9f874f1/
Log: in-progress
diff --git a/rpython/memory/gctransform/shadowcolor.py
b/rpython/memory/gctransform/shadowcolor.py
--- a/rpython/memory/gctransform/shadowcolor.py
+++ b/rpython/memory/gctransform/shadowcolor.py
@@ -100,8 +100,35 @@
return regalloc
+def move_pushes_earlier(graph):
+ """gc_push_roots and gc_pop_roots are pushes/pops to the shadowstack,
+ immediately enclosing the operation that needs them (typically a call).
+ Here, we try to move individual pushes earlier, in fact as early as
+ possible under the following conditions: we only move it across vars
+ that are 'interesting_vars'; and we stop when we encounter the
+ operation that produces the value, or when we encounter a gc_pop_roots
+ that pops off the same stack location. In the latter case, if that
+ gc_pop_roots pops the same value out of the same stack location, then
+ success: we can remove the gc_push_root on that path.
+
+ If the process succeeds to remove the gc_push_root along at least
+ one path, we generate it explicitly on the other paths, and we
+ remove the original gc_push_root. If the process doesn't succeed
+ in doing any such removal, we don't do anything.
+
+ Note that it would be possible to do exactly the same in the
+ opposite direction by exchanging the roles of "push/earlier" and
+ "pop/later". I think doing both is pointless---one direction is
+ enough. The direction we chose here keeps gc_pop_roots unmodified.
+ The C compiler should be better at discarding them if unused.
+ """
+
+ x.x.x.x
+
+
def postprocess_graph(gct, graph):
"""Collect information about the gc_push_roots and gc_pop_roots
added in this complete graph, and replace them with real operations.
"""
+ regalloc = allocate_registers(graph)
xxxx
diff --git a/rpython/memory/gctransform/shadowstack.py
b/rpython/memory/gctransform/shadowstack.py
--- a/rpython/memory/gctransform/shadowstack.py
+++ b/rpython/memory/gctransform/shadowstack.py
@@ -33,7 +33,7 @@
return livevars
def pop_roots(self, hop, livevars):
- hop.genop("gc_pop_roots", livevars) # even if len(livevars) == 0
+ hop.genop("gc_pop_roots", list(livevars)) # even if len(livevars) == 0
class ShadowStackRootWalker(BaseRootWalker):
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