The function kill_dead_stores() is somehow hard to understand.
Let's add some explanation for it.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
flow.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/flow.c b/flow.c
index 32e30670c..2732b922d 100644
--- a/flow.c
+++ b/flow.c
@@ -551,6 +551,20 @@ found:
}
/* Kill a pseudo that is dead on exit from the bb */
+// The context is:
+// * the variable is not global but may have its address used (local/non-local)
+// * the stores are only needed by others functions which would do some
+// loads via the escaped address
+// We start by the terminating BB (normal exit BB + no-return/unreachable)
+// We walkup the BB' intruction backward
+// * we're only concerned by loads, stores & calls
+// * if we reach a call -> we have to stop if var is non-local
+// * if we reach a load of our var -> we have to stop
+// * if we reach a store of our var -> we can kill it, it's dead
+// * we can ignore other stores & loads if the var is local
+// * if we reach another store or load done via non-symbol access
+// (so done via some address calculation) -> we have to stop
+// If we reach the top of the BB we can recurse into the parents BBs.
static void kill_dead_stores(pseudo_t pseudo, unsigned long generation, struct basic_block *bb, int local)
{
struct instruction *insn;
--
2.16.2
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