@@ -650,11 +650,10 @@ void check_access(struct instruction *insn)
static void simplify_one_symbol(struct entrypoint *ep, struct symbol *sym)
{
- pseudo_t pseudo, src;
+ pseudo_t pseudo;
struct pseudo_user *pu;
- struct instruction *def;
unsigned long mod;
- int all, stores, complex;
+ int all;
/* Never used as a symbol? */
pseudo = sym->pseudo;
@@ -670,17 +669,12 @@ static void simplify_one_symbol(struct entrypoint *ep, struct symbol *sym)
if (mod)
goto external_visibility;
- def = NULL;
- stores = 0;
- complex = 0;
FOR_EACH_PTR(pseudo->users, pu) {
/* We know that the symbol-pseudo use is the "src" in the instruction */
struct instruction *insn = pu->insn;
switch (insn->opcode) {
case OP_STORE:
- stores++;
- def = insn;
break;
case OP_LOAD:
break;
@@ -697,37 +691,8 @@ static void simplify_one_symbol(struct entrypoint *ep, struct symbol *sym)
default:
warning(sym->pos, "symbol '%s' pseudo used in unexpected way", show_ident(sym->ident));
}
- complex |= insn->offset;
} END_FOR_EACH_PTR(pu);
- if (complex)
- goto complex_def;
- if (stores > 1)
- goto multi_def;
-
- /*
- * Goodie, we have a single store (if even that) in the whole
- * thing. Replace all loads with moves from the pseudo,
- * replace the store with a def.
- */
- src = VOID;
- if (def)
- src = def->target;
-
- FOR_EACH_PTR(pseudo->users, pu) {
- struct instruction *insn = pu->insn;
- if (insn->opcode == OP_LOAD) {
- check_access(insn);
- convert_load_instruction(insn, src);
- }
- } END_FOR_EACH_PTR(pu);
-
- /* Turn the store into a no-op */
- kill_store(def);
- return;
-
-multi_def:
-complex_def:
external_visibility:
all = 1;
FOR_EACH_PTR_REVERSE(pseudo->users, pu) {
Current sparse code doesn't handle very gracefully code with undefined pseudos. These can occurs, of course because the dev has not initialize them, maybe by error, but they can also occurs when they are only set (and used) in a single path or even worse, hen initiializing a bitfield. The origin of the problem is the single store shortcut in simplify_one_symbol() which doesn't take in account the (absence of) dominance when loads exist without stores. Fix this by removing this single-store shortcut and leave all the work for the general case which handle this situation quite well (and/but set those variables to 0). Warning: this change impact the performance. Note: this will also solve most infinite loops that can happen when processing undefined vars. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> --- flow.c | 39 ++------------------------------------- 1 file changed, 2 insertions(+), 37 deletions(-)