diff options
Diffstat (limited to 'staptree.cxx')
| -rw-r--r-- | staptree.cxx | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/staptree.cxx b/staptree.cxx index 2f62198f..75c2c17d 100644 --- a/staptree.cxx +++ b/staptree.cxx @@ -1495,19 +1495,19 @@ functioncall_traversing_visitor::visit_functioncall (functioncall* e) void varuse_collecting_visitor::visit_embeddedcode (embeddedcode *s) { - // In order to elide unused but correct functions generated to - // get $target variables, we encode our knowledge that such - // functions are side-effect-free. We tell them apart from ordinary - // tapset embedded-C functions by the naming prefix. XXX Something - // apart from this heuristic would be nice. XXX Similarly, some - // tapset embedded-C functions are pure and disposable, like - // substr(). + // We want to elide embedded-C functions when possible. For + // example, each $target variable access is expanded to an + // embedded-C function call. Yet, for safety reasons, we should + // presume that embedded-C functions have intentional side-effects. + // + // To tell these two types of functions apart, we apply a + // Kludge(tm): we look for a magic string within the function body. + // $target variables as rvalues will have this; lvalues won't. + // Also, explicit side-effect-free tapset functions will have this. assert (current_function); // only they get embedded code - string name = current_function->name; - if (name.length() > 10 && name.substr(0, 10) == "_tvar_get_") + if (s->code.find ("/* pure */") != string::npos) return; - // NB: setter functions naturally have side-effects embedded_seen = true; } @@ -1520,7 +1520,12 @@ varuse_collecting_visitor::visit_print_format (print_format* e) // are implemented as statement-expressions containing a // print_format. They have side-effects, but not via the // embedded-code detection method above. - embedded_seen = true; + // + // But sprint and sprintf don't have side-effects. + + if (e->print_to_stream) + embedded_seen = true; // a proxy for "has unknown side-effects" + functioncall_traversing_visitor::visit_print_format (e); } @@ -2185,6 +2190,7 @@ deep_copy_visitor::visit_print_format (print_format* e) n->tok = e->tok; n->print_with_format = e->print_with_format; n->print_to_stream = e->print_to_stream; + n->raw_components = e->raw_components; n->components = e->components; for (unsigned i = 0; i < e->args.size(); ++i) { |