diff options
| -rw-r--r-- | ChangeLog | 10 | ||||
| -rw-r--r-- | parse.cxx | 124 | ||||
| -rw-r--r-- | parse.h | 4 |
3 files changed, 90 insertions, 48 deletions
@@ -13,6 +13,16 @@ 2008-06-10 Frank Ch. Eigler <fche@elastic.org> PR 6470 + * parse.cxx (scan_pp): Eliminate expand_args argument to control + nested preprocess evaluation. Rewrite to use a combination of + exceptions and non-recursion. + (lexer::scan): Ditto. Interpret "$#" as the argc value in all + cases. + * parse.h: Corresponding decl changes. + +2008-06-10 Frank Ch. Eigler <fche@elastic.org> + + PR 6470 * parse.cxx (eval_comparison): New template function. (eval_pp_conditional): Call it separately for string/string and int64/int64 cases. @@ -291,10 +291,9 @@ bool eval_pp_conditional (systemtap_session& s, } -// expand_args is used to know if we must expand $x and @x identifiers. // Only tokens corresponding to the TRUE statement must be expanded const token* -parser::scan_pp (bool wildcard, bool expand_args) +parser::scan_pp (bool wildcard) { while (true) { @@ -305,7 +304,7 @@ parser::scan_pp (bool wildcard, bool expand_args) return t; } - const token* t = input.scan (wildcard, expand_args); // NB: not recursive! + const token* t = input.scan (wildcard); // NB: not recursive! if (t == 0) // EOF return t; @@ -315,9 +314,9 @@ parser::scan_pp (bool wildcard, bool expand_args) // We have a %( - it's time to throw a preprocessing party! const token *l, *op, *r; - l = input.scan (false, expand_args); // NB: not recursive, though perhaps could be - op = input.scan (false, expand_args); - r = input.scan (false, expand_args); + l = input.scan (false); // NB: not recursive, though perhaps could be + op = input.scan (false); + r = input.scan (false); if (l == 0 || op == 0 || r == 0) throw parse_error ("incomplete condition after '%('", t); // NB: consider generalizing to consume all tokens until %?, and @@ -325,67 +324,102 @@ parser::scan_pp (bool wildcard, bool expand_args) // Do not evaluate the condition if we haven't expanded everything. // This may occur when having several recursive conditionals. - bool result = expand_args && eval_pp_conditional (session, l, op, r); + bool result = eval_pp_conditional (session, l, op, r); delete l; delete op; delete r; - + + /* + clog << "PP eval (" << *t << ") == " << result << endl; + */ + const token *m = input.scan (); // NB: not recursive if (! (m && m->type == tok_operator && m->content == "%?")) throw parse_error ("expected '%?' marker for conditional", t); delete m; // "%?" vector<const token*> my_enqueued_pp; - bool have_token = false; - + + int nesting = 0; while (true) // consume THEN tokens { - m = scan_pp (wildcard, result); // NB: recursive - if (m == 0) - throw parse_error (have_token ? - "incomplete conditional - missing %: or %)" : - "missing THEN tokens for conditional", - t); - - have_token = true; - if (m->type == tok_operator && (m->content == "%:" || // ELSE - m->content == "%)")) // END + try + { + m = result ? scan_pp (wildcard) : input.scan (wildcard); + } + catch (const parse_error &e) + { + if (result) throw e; // propagate errors if THEN branch taken + m = 0; + } + + if (m && m->type == tok_operator && m->content == "%(") // nested %( + nesting ++; + if (nesting == 0 && m && (m->type == tok_operator && (m->content == "%:" || // ELSE + m->content == "%)"))) // END break; - // enqueue token - if (result) + if (nesting && m && m->type == tok_operator && m->content == "%)") // nested %) + nesting --; + + if (result && !m) + throw parse_error ("unexpected end-of-file"); + if (result && m) my_enqueued_pp.push_back (m); - else - delete m; // unused token - // continue + if (!result && !m) + // do nothing; probably a parse error in an unkept THEN token + if (!result && m) + delete m; // do nothing, just dispose of unkept THEN token + + continue; } - have_token = false; if (m && m->type == tok_operator && m->content == "%:") // ELSE { delete m; // "%:" + int nesting = 0; while (true) { - m = scan_pp (wildcard, expand_args && !result); // NB: recursive - if (m == 0) - throw parse_error (have_token ? - "incomplete conditional - missing %)" : - "missing ELSE tokens for conditional", - t); - - have_token = true; - if (m->type == tok_operator && m->content == "%)") // END + try + { + m = result ? input.scan (wildcard) : scan_pp (wildcard); + } + catch (const parse_error& e) + { + if (!result) throw e; // propagate errors if ELSE branch taken + m = 0; + } + + if (m && m->type == tok_operator && m->content == "%(") // nested %( + nesting ++; + if (nesting == 0 && m && m->type == tok_operator && m->content == "%)") // END break; - // enqueue token - if (! result) - my_enqueued_pp.push_back (m); - else - delete m; // unused token - // continue + if (nesting && m && m->type == tok_operator && m->content == "%)") // nested %) + nesting --; + + if (!result && !m) + throw parse_error ("incomplete conditional - missing %)", t); + if (!result && m) + my_enqueued_pp.push_back (m); + if (result && !m) + // do nothing; probably a parse error in an unkept ELSE token + if (result && m) + delete m; // do nothing, just dispose of unkept ELSE token + + continue; } } + + /* + clog << "PP eval (" << *t << ") == " << result << " tokens: " << endl; + for (unsigned k=0; k<my_enqueued_pp.size(); k++) + clog << * my_enqueued_pp[k] << endl; + clog << endl; + */ + delete t; // "%(" delete m; // "%)" + // NB: we transcribe the retained tokens here, and not inside // the THEN/ELSE while loops. If it were done there, each loop // would become infinite (each iteration consuming an ordinary @@ -605,7 +639,7 @@ lexer::input_put (const string& chars) token* -lexer::scan (bool wildcard, bool expand_args) +lexer::scan (bool wildcard) { token* n = new token; n->location.file = input_name; @@ -640,8 +674,7 @@ lexer::scan (bool wildcard, bool expand_args) // characters; @1..@999 are quoted/escaped as strings. // $# and @# expand to the number of arguments, similarly // raw or quoted. - if (expand_args && - (c == '$' || c == '@') && + if ((c == '$' || c == '@') && (c2 == '#')) { input_get(); // swallow '#' @@ -652,8 +685,7 @@ lexer::scan (bool wildcard, bool expand_args) semiskipped_p ++; goto semiskip; } - else if (expand_args && - (c == '$' || c == '@') && + else if ((c == '$' || c == '@') && (isdigit (c2))) { unsigned idx = 0; @@ -69,7 +69,7 @@ struct systemtap_session; class lexer { public: - token* scan (bool wildcard=false, bool expand_args=true); + token* scan (bool wildcard=false); lexer (std::istream&, const std::string&, systemtap_session&); private: @@ -132,7 +132,7 @@ private: // preprocessing subordinate std::vector<const token*> enqueued_pp; - const token* scan_pp (bool wildcard=false, bool expand_args=true); + const token* scan_pp (bool wildcard=false); // scanning state const token* last (); |