During linearization, most kinds of instruction are not generated
if there is no active BB (which mean that these instructions can
never be executed).
However, loads & stores are generated anyway. These dead loads
and stores will then need to be removed which is a bit tricky:
- memops are special and more complex to be removed than
instructions like 'add' and such.
- these instructions exist in 'phantom basic blocks': a BB
which has ia null bb->ep and which doesn't belong to then
entrypoint's ep->bbs. Such blocks are considered as removed
and are never scanned or anything.
Keep things simple and avoid to generate memops in inactive
basic blocks.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
linearize.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/linearize.c b/linearize.c
index 54cdf116f..be0e811f2 100644
--- a/linearize.c
+++ b/linearize.c
@@ -935,6 +935,9 @@ static pseudo_t add_load(struct entrypoint *ep, struct access_data *ad)
struct instruction *insn;
pseudo_t new;
+ if (!ep->active)
+ return VOID;
+
insn = alloc_typed_instruction(OP_LOAD, btype);
new = alloc_pseudo(insn);
@@ -968,6 +971,9 @@ static pseudo_t linearize_store_gen(struct entrypoint *ep,
struct symbol *btype = bitfield_base_type(ctype);
pseudo_t store = value;
+ if (!ep->active)
+ return VOID;
+
if (type_size(btype) != type_size(ctype)) {
unsigned int shift = ctype->bit_offset;
unsigned int size = ctype->bit_size;
@@ -1031,8 +1037,12 @@ static pseudo_t linearize_load_gen(struct entrypoint *ep, struct access_data *ad
{
struct symbol *ctype = ad->type;
struct symbol *btype = bitfield_base_type(ctype);
- pseudo_t new = add_load(ep, ad);
+ pseudo_t new;
+
+ if (!ep->active)
+ return VOID;
+ new = add_load(ep, ad);
if (ctype->bit_offset) {
pseudo_t shift = value_pseudo(ctype->bit_offset);
pseudo_t newval = add_binary_op(ep, btype, OP_LSR, new, shift);
--
2.16.2
--
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