On Mon, Jun 19, 2017 at 03:50:42PM +0200, Martin Liška wrote:
> @@ -858,6 +862,117 @@ sanitize_asan_mark_poison (void)
> }
> }
>
Missing function comment.
> +static tree
> +rewrite_usage_of_param (tree *op, int *walk_subtrees, void *data)
> +{
> + struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
> + std::pair<tree, tree> *replacement = (std::pair<tree, tree> *)wi->info;
Missing space after )
> +
> + if (*op == replacement->first)
> + {
> + *op = replacement->second;
> + *walk_subtrees = 0;
> + }
> +
> + return NULL;
> +}
> +static void
> +sanitize_rewrite_addressable_params (function *fun)
> +{
> + basic_block entry_bb = NULL;
> +
> + for (tree arg = DECL_ARGUMENTS (current_function_decl);
> + arg; arg = DECL_CHAIN (arg))
> + {
> + if (TREE_ADDRESSABLE (arg) && !TREE_ADDRESSABLE (TREE_TYPE (arg)))
> + {
> + /* The parameter is no longer addressable. */
> + tree type = TREE_TYPE (arg);
> + TREE_ADDRESSABLE (arg) = 0;
> +
> + /* Create a new automatic variable. */
> + tree var = build_decl (DECL_SOURCE_LOCATION (arg),
> + VAR_DECL, DECL_NAME (arg), type);
> + TREE_ADDRESSABLE (var) = 1;
> + DECL_ARTIFICIAL (var) = 1;
> + DECL_SEEN_IN_BIND_EXPR_P (var) = 0;
I think it is highly inefficient to walk the whole IL for every addressable
argument. Can't you first find out what PARM_DECLs you need to change,
stick the corresponding VAR_DECL somewhere (dunno, e.g. a vector with pairs
perhaps sorted by DECL_UID, or stick it into DECL_VALUE_EXPR or whatever),
then if you create at least one, walk whole IL and replace all the
PARM_DECLs you want to replace, then finally clear the TREE_ADDRESSABLE
flag for all of them and emit the initialization sequence?
Then something needs to be done for debugging too. If it is without VTA,
then probably just having DECL_VALUE_EXPR is good enough, otherwise
(VTA) you probably don't want that (or can reset it at that point), but
instead emit after the initialization stmt a debug stmt that the variable
value now lives in a different var. Though ideally we want the debugger
to be able to also change the value of the var, that might be harder.
With DECL_VALUE_EXPR on the other side the debug info will be incorrect in
the prologue until it is assigned to the slot.
> +
> + gimple_add_tmp_var (var);
> +
> + if (dump_file)
> + fprintf (dump_file,
> + "Rewritting parameter whos address is taken: %s\n",
> + IDENTIFIER_POINTER (DECL_NAME (arg)));
s/tting/ting/, s/whos/whose/
> +
> + gimple_seq stmts = NULL;
> +
> + /* Assign value of parameter to newly created variable. */
> + if ((TREE_CODE (type) == COMPLEX_TYPE
> + || TREE_CODE (type) == VECTOR_TYPE))
> + {
> + /* We need to create a SSA name that will be used for the
> + assignment. */
> + tree tmp = make_ssa_name (type);
> + gimple *g = gimple_build_assign (tmp, arg);
> + gimple_set_location (g, DECL_SOURCE_LOCATION (arg));
> + gimple_seq_add_stmt (&stmts, g);
> + g = gimple_build_assign (var, tmp);
> + gimple_set_location (g, DECL_SOURCE_LOCATION (arg));
> + gimple_seq_add_stmt (&stmts, g);
> + }
> + else
> + {
> + gimple *g = gimple_build_assign (var, arg);
> + gimple_set_location (g, DECL_SOURCE_LOCATION (arg));
> + gimple_seq_add_stmt (&stmts, g);
> + }
I don't understand the distinction. If you turn the original parm
for complex/vector DECL_GIMPLE_REG_P, you should need the exact same code
(but I think it would be better to use the default SSA_NAME of the PARM_DECL
if it is a gimple reg type, rather than use the PARM_DECL itself
and wait for update_ssa).
Jakub
