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| author | Frank Ch. Eigler <fche@elastic.org> | 2010-02-23 20:31:00 -0500 |
|---|---|---|
| committer | Frank Ch. Eigler <fche@elastic.org> | 2010-02-23 20:31:00 -0500 |
| commit | 30263a7389d5c2712536b74656193708bbc64d49 (patch) | |
| tree | b10b72dd3db455abf95a8ab21c540069c0143860 /elaborate.cxx | |
| parent | d6c273473f7bea4d696c95ca48d55ca26e25ab2f (diff) | |
| download | systemtap-steved-30263a7389d5c2712536b74656193708bbc64d49.tar.gz systemtap-steved-30263a7389d5c2712536b74656193708bbc64d49.tar.xz systemtap-steved-30263a7389d5c2712536b74656193708bbc64d49.zip | |
PR11005: @defined($tvar) predicate, part 1
* staptree.h (defined_op): New class.
* all files: Extend all visitors as appropriate, mostly
dummy/pass-through implementation.
* parse.cxx (parse_target_symbol): New function, factored out
of parse_symbol().
(parse_define_op): New function.
* NEWS: Mention it.
* parse.h: Corresponding changes.
* tapsets.cxx (var_expanding_visitor::visit_defined_op):
Implement @defined() semantics.
(dwarf_var_expanding_visitor::visit_target_symbol): Adjust.
* tapset-utrace.c (visit_target_symbol_arg): Avoid crashes
on $argZZZ.
* tapsets.cxx (sdt_var_expanding_visitor): Ditto.
* semok/thirtysix.stp: New test.
Diffstat (limited to 'elaborate.cxx')
| -rw-r--r-- | elaborate.cxx | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/elaborate.cxx b/elaborate.cxx index 88a856c2..127e0bda 100644 --- a/elaborate.cxx +++ b/elaborate.cxx @@ -1243,6 +1243,7 @@ semantic_pass_symbols (systemtap_session& s) } + // Keep unread global variables for probe end value display. void add_global_var_display (systemtap_session& s) { @@ -2609,6 +2610,7 @@ struct void_statement_reducer: public update_visitor void visit_print_format (print_format* e); void visit_target_symbol (target_symbol* e); void visit_cast_op (cast_op* e); + void visit_defined_op (defined_op* e); // these are a bit hairy to grok due to the intricacies of indexables and // stats, so I'm chickening out and skipping them... @@ -2947,6 +2949,23 @@ void_statement_reducer::visit_cast_op (cast_op* e) } +void +void_statement_reducer::visit_defined_op (defined_op* e) +{ + // When the result of a @defined operation isn't needed, just elide + // it entirely. Its operand $expression must already be + // side-effect-free. + + if (session.verbose>2) + clog << "Eliding unused check " << *e->tok << endl; + + relaxed_p = false; + e = 0; + provide (e); +} + + + void semantic_pass_opt5 (systemtap_session& s, bool& relaxed_p) { // Let's simplify statements with unused computed values. @@ -3576,6 +3595,13 @@ typeresolution_info::visit_target_symbol (target_symbol* e) void +typeresolution_info::visit_defined_op (defined_op* e) +{ + throw semantic_error("unexpected @defined", e->tok); +} + + +void typeresolution_info::visit_cast_op (cast_op* e) { // Like target_symbol, a cast_op shouldn't survive this far |