Hi,
On Wed, Jan 02, 2008 at 06:13:37PM -0500, Rob Johnson wrote:
> I'm experimenting with the gimple plugin infrastructure and I'm having
> trouble instrumenting code in a way that is compatible with the optimizer.
> Here's a simple example that is intended to insert the function call
> "__memcheck_register_argv(argc, argv)" at the beginning of main. The code
> runs during pass_plugin_gimple (which comes right after pass_apply_inline
> in passes.c) and works great with -O0, but causes the compiler to crash
> with -O1 or higher.
>
> -------------------------------------
> tree argv_registrar_type;
> tree argv_registrar;
> tree argv_registrar_call;
>
> argv_registrar_type = build_function_type_list (void_type_node,
> integer_type_node,
> build_pointer_type
> (build_pointer_type
> (char_type_node)),
> NULL_TREE);
> argv_registrar = build_fn_decl ("__memcheck_register_argv",
> argv_registrar_type);
> argv_registrar_call = build_call_expr (argv_registrar, 2,
> DECL_ARGUMENTS (cfun->decl),
> TREE_CHAIN (DECL_ARGUMENTS
> (cfun->decl)));
DECL_ARGUMENTS is a tree chain of PARM_DECLs and in SSA GIMPLE, scalar
operands (integers and pointer are both scalar, is_gimple_reg()
predicate is there to identify variables that need to be converted to
SSA) need to be SSA_NAMEs of declarations (PARM_DECLs and VAR_DECLs in
particular).
Therefore I suspect you need to create a different chain of respective
SSA_NAMES and pass that to build_call_expr(). You can get the default
SSA_NAME by calling gimple_default_def().
> bsi_insert_before (&iter, argv_registrar_call, BSI_SAME_STMT);
> ---------------------------------------
>
> With -O1, I get the compiler failure
>
> ---------------
> test.c: In function 'main':
> test.c:2: error: expected an SSA_NAME object
> test.c:2: error: in statement
> __memcheck_register_argv (argc, argv);
> test.c:2: internal compiler error: verify_ssa failed
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <URL:http://gcc.gnu.org/bugs.html> for instructions.
> ----------------
>
> when attempting to compile the code
>
> -----------------
> int main(int argc, char **argv)
> {
> return 0;
> }
> -----------------
>
>
HTH
Martin
