staptree.h

   1 // -*- C++ -*-
   2 // Copyright (C) 2005-2011 Red Hat Inc.
   3 // Copyright (C) 2006 Intel Corporation.
   4 //
   5 // This file is part of systemtap, and is free software.  You can
   6 // redistribute it and/or modify it under the terms of the GNU General
   7 // Public License (GPL); either version 2, or (at your option) any
   8 // later version.
   9
  10 #ifndef STAPTREE_H
  11 #define STAPTREE_H
  12
  13 #include <map>
  14 #include <stack>
  15 #include <set>
  16 #include <string>
  17 #include <vector>
  18 #include <iostream>
  19 #include <stdexcept>
  20 #include <cassert>
  21 extern "C" {
  22 #include <stdint.h>
  23 }
  24
  25 struct token; // parse.h
  26 struct systemtap_session; // session.h
  27
  28 struct semantic_error: public std::runtime_error
  29 {
  30   const token* tok1;
  31   std::string msg2;
  32   const token* tok2;
  33   semantic_error *chain;
  34
  35   ~semantic_error () throw () {}
  36   semantic_error (const std::string& msg, const token* t1=0):
  37     runtime_error (msg), tok1 (t1), tok2 (0), chain (0) {}
  38   semantic_error (const std::string& msg, const token* t1,
  39                   const std::string& m2, const token* t2):
  40     runtime_error (msg), tok1 (t1), msg2 (m2), tok2 (t2), chain (0) {}
  41 };
  42
  43 // ------------------------------------------------------------------------
  44
  45 /* struct statistic_decl moved to session.h */
  46
  47 // ------------------------------------------------------------------------
  48
  49 enum exp_type
  50   {
  51     pe_unknown,
  52     pe_long,   // int64_t
  53     pe_string, // std::string
  54     pe_stats
  55   };
  56
  57 std::ostream& operator << (std::ostream& o, const exp_type& e);
  58
  59 struct token;
  60 struct visitor;
  61 struct update_visitor;
  62
  63 struct expression
  64 {
  65   exp_type type;
  66   const token* tok;
  67   expression ();
  68   virtual ~expression ();
  69   virtual void print (std::ostream& o) const = 0;
  70   virtual void visit (visitor* u) = 0;
  71 };
  72
  73 std::ostream& operator << (std::ostream& o, const expression& k);
  74
  75
  76 struct literal: public expression
  77 {
  78 };
  79
  80
  81 struct literal_string: public literal
  82 {
  83   std::string value;
  84   literal_string (const std::string& v);
  85   void print (std::ostream& o) const;
  86   void visit (visitor* u);
  87 };
  88
  89
  90 struct literal_number: public literal
  91 {
  92   int64_t value;
  93   bool print_hex;
  94   literal_number (int64_t v, bool hex=false);
  95   void print (std::ostream& o) const;
  96   void visit (visitor* u);
  97 };
  98
  99
 100 struct embedded_expr: public expression
 101 {
 102   std::string code;
 103   void print (std::ostream& o) const;
 104   void visit (visitor* u);
 105 };
 106
 107
 108 struct binary_expression: public expression
 109 {
 110   expression* left;
 111   std::string op;
 112   expression* right;
 113   void print (std::ostream& o) const;
 114   void visit (visitor* u);
 115 };
 116
 117
 118 struct unary_expression: public expression
 119 {
 120   std::string op;
 121   expression* operand;
 122   void print (std::ostream& o) const;
 123   void visit (visitor* u);
 124 };
 125
 126
 127 struct pre_crement: public unary_expression
 128 {
 129   void visit (visitor* u);
 130 };
 131
 132
 133 struct post_crement: public unary_expression
 134 {
 135   void print (std::ostream& o) const;
 136   void visit (visitor* u);
 137 };
 138
 139
 140 struct logical_or_expr: public binary_expression
 141 {
 142   void visit (visitor* u);
 143 };
 144
 145
 146 struct logical_and_expr: public binary_expression
 147 {
 148   void visit (visitor* u);
 149 };
 150
 151
 152 struct arrayindex;
 153 struct array_in: public expression
 154 {
 155   arrayindex* operand;
 156   void print (std::ostream& o) const;
 157   void visit (visitor* u);
 158 };
 159
 160
 161 struct comparison: public binary_expression
 162 {
 163   void visit (visitor* u);
 164 };
 165
 166
 167 struct concatenation: public binary_expression
 168 {
 169   void visit (visitor* u);
 170 };
 171
 172
 173 struct ternary_expression: public expression
 174 {
 175   expression* cond;
 176   expression* truevalue;
 177   expression* falsevalue;
 178   void print (std::ostream& o) const;
 179   void visit (visitor* u);
 180 };
 181
 182
 183 struct assignment: public binary_expression
 184 {
 185   void visit (visitor* u);
 186 };
 187
 188 struct symbol;
 189 struct hist_op;
 190 struct indexable
 191 {
 192   // This is a helper class which, type-wise, acts as a disjoint union
 193   // of symbols and histograms. You can ask it whether it's a
 194   // histogram or a symbol, and downcast accordingly.
 195   void print_indexable (std::ostream& o) const;
 196   void visit_indexable (visitor* u);
 197   virtual bool is_symbol(symbol *& sym_out);
 198   virtual bool is_hist_op(hist_op *& hist_out);
 199   virtual bool is_const_symbol(const symbol *& sym_out) const;
 200   virtual bool is_const_hist_op(const hist_op *& hist_out) const;
 201   virtual const token *get_tok() const = 0;
 202   virtual ~indexable() {}
 203 };
 204
 205 // Perform a downcast to one out-value and NULL the other, throwing an
 206 // exception if neither downcast succeeds. This is (sadly) about the
 207 // best we can accomplish in C++.
 208 void
 209 classify_indexable(indexable* ix,
 210                    symbol *& array_out,
 211                    hist_op *& hist_out);
 212
 213 void
 214 classify_const_indexable(const indexable* ix,
 215                          symbol const *& array_out,
 216                          hist_op const *& hist_out);
 217
 218 class vardecl;
 219 struct symbol:
 220   public expression,
 221   public indexable
 222 {
 223   std::string name;
 224   vardecl *referent;
 225   symbol ();
 226   void print (std::ostream& o) const;
 227   void visit (visitor* u);
 228   // overrides of type 'indexable'
 229   const token *get_tok() const;
 230   bool is_const_symbol(const symbol *& sym_out) const;
 231   bool is_symbol(symbol *& sym_out);
 232 };
 233
 234
 235 struct target_symbol: public symbol
 236 {
 237   enum component_type
 238     {
 239       comp_struct_member,
 240       comp_literal_array_index,
 241       comp_expression_array_index,
 242       comp_pretty_print, // must be final
 243     };
 244
 245   struct component
 246     {
 247       const token* tok;
 248       component_type type;
 249       std::string member; // comp_struct_member, comp_pretty_print
 250       int64_t num_index; // comp_literal_array_index
 251       expression* expr_index; // comp_expression_array_index
 252
 253       component(const token* t, const std::string& m, bool pprint=false):
 254         tok(t),
 255         type(pprint ? comp_pretty_print : comp_struct_member),
 256         member(m), num_index(0), expr_index(0)
 257       {}
 258       component(const token* t, int64_t n):
 259         tok(t), type(comp_literal_array_index), num_index(n),
 260         expr_index(0) {}
 261       component(const token* t, expression* e):
 262         tok(t), type(comp_expression_array_index), num_index(0),
 263          expr_index(e) {}
 264       void print (std::ostream& o) const;
 265     };
 266
 267   bool addressof;
 268   std::vector<component> components;
 269   semantic_error* saved_conversion_error; // hand-made linked list
 270   target_symbol(): addressof(false), saved_conversion_error (0) {}
 271   void chain (const semantic_error& er);
 272   void print (std::ostream& o) const;
 273   void visit (visitor* u);
 274   void visit_components (visitor* u);
 275   void visit_components (update_visitor* u);
 276   void assert_no_components(const std::string& tapset, bool pretty_ok=false);
 277 };
 278
 279 std::ostream& operator << (std::ostream& o, const target_symbol::component& c);
 280
 281
 282 struct cast_op: public target_symbol
 283 {
 284   expression *operand;
 285   std::string type_name, module;
 286   void print (std::ostream& o) const;
 287   void visit (visitor* u);
 288 };
 289
 290
 291 struct defined_op: public expression
 292 {
 293   target_symbol *operand;
 294   void print (std::ostream& o) const;
 295   void visit (visitor* u);
 296 };
 297
 298
 299 struct entry_op: public expression
 300 {
 301   expression *operand;
 302   void print (std::ostream& o) const;
 303   void visit (visitor* u);
 304 };
 305
 306
 307 struct arrayindex: public expression
 308 {
 309   std::vector<expression*> indexes;
 310   indexable *base;
 311   arrayindex ();
 312   void print (std::ostream& o) const;
 313   void visit (visitor* u);
 314 };
 315
 316
 317 class functiondecl;
 318 struct functioncall: public expression
 319 {
 320   std::string function;
 321   std::vector<expression*> args;
 322   functiondecl *referent;
 323   functioncall ();
 324   void print (std::ostream& o) const;
 325   void visit (visitor* u);
 326 };
 327
 328
 329 struct print_format: public expression
 330 {
 331   bool print_to_stream;
 332   bool print_with_format;
 333   bool print_with_delim;
 334   bool print_with_newline;
 335   bool print_char;
 336
 337   // XXX match runtime/vsprintf.c's print_flag
 338   // ... for use with number() & number_size()
 339   enum format_flag
 340     {
 341       fmt_flag_zeropad = 1,
 342       fmt_flag_sign = 2,
 343       fmt_flag_plus = 4,
 344       fmt_flag_space = 8,
 345       fmt_flag_left = 16,
 346       fmt_flag_special = 32,
 347       fmt_flag_large = 64,
 348     };
 349
 350   enum conversion_type
 351     {
 352       conv_unspecified,
 353       conv_pointer,
 354       conv_number,
 355       conv_string,
 356       conv_char,
 357       conv_memory,
 358       conv_memory_hex,
 359       conv_literal,
 360       conv_binary
 361     };
 362
 363   enum width_type
 364     {
 365       width_unspecified,
 366       width_static,
 367       width_dynamic
 368     };
 369
 370   enum precision_type
 371     {
 372       prec_unspecified,
 373       prec_static,
 374       prec_dynamic
 375     };
 376
 377   struct format_component
 378   {
 379     unsigned long flags;
 380     unsigned base;
 381     unsigned width;
 382     unsigned precision;
 383     width_type widthtype;
 384     precision_type prectype;
 385     conversion_type type;
 386     std::string literal_string;
 387     bool is_empty() const
 388     {
 389       return flags == 0
 390         && widthtype == width_unspecified
 391         && prectype == prec_unspecified
 392         && type == conv_unspecified
 393         && literal_string.empty();
 394     }
 395     void clear()
 396     {
 397       flags = 0;
 398       widthtype = width_unspecified;
 399       prectype = prec_unspecified;
 400       type = conv_unspecified;
 401       literal_string.clear();
 402     }
 403     inline void set_flag(format_flag f) { flags |= f; }
 404     inline bool test_flag(format_flag f) const { return flags & f; }
 405   };
 406
 407   std::string raw_components;
 408   std::vector<format_component> components;
 409   format_component delimiter;
 410   std::vector<expression*> args;
 411   hist_op *hist;
 412
 413   static std::string components_to_string(std::vector<format_component> const & components);
 414   static std::vector<format_component> string_to_components(std::string const & str);
 415   static print_format* create(const token *t);
 416
 417   void print (std::ostream& o) const;
 418   void visit (visitor* u);
 419
 420 private:
 421   print_format(bool stream, bool format, bool delim, bool newline, bool _char):
 422     print_to_stream(stream), print_with_format(format),
 423     print_with_delim(delim), print_with_newline(newline),
 424     print_char(_char), hist(NULL)
 425   {}
 426 };
 427
 428
 429 enum stat_component_type
 430   {
 431     sc_average,
 432     sc_count,
 433     sc_sum,
 434     sc_min,
 435     sc_max,
 436   };
 437
 438 struct stat_op: public expression
 439 {
 440   stat_component_type ctype;
 441   expression* stat;
 442   void print (std::ostream& o) const;
 443   void visit (visitor* u);
 444 };
 445
 446 enum histogram_type
 447   {
 448     hist_linear,
 449     hist_log
 450   };
 451
 452 struct hist_op: public indexable
 453 {
 454   const token* tok;
 455   histogram_type htype;
 456   expression* stat;
 457   std::vector<int64_t> params;
 458   void print (std::ostream& o) const;
 459   void visit (visitor* u);
 460   // overrides of type 'indexable'
 461   const token *get_tok() const;
 462   bool is_const_hist_op(const hist_op *& hist_out) const;
 463   bool is_hist_op(hist_op *& hist_out);
 464 };
 465
 466 // ------------------------------------------------------------------------
 467
 468
 469 struct symboldecl // unique object per (possibly implicit)
 470                   // symbol declaration
 471 {
 472   const token* tok;
 473   const token* systemtap_v_conditional; //checking systemtap compatibility
 474   std::string name;
 475   exp_type type;
 476   symboldecl ();
 477   virtual ~symboldecl ();
 478   virtual void print (std::ostream &o) const = 0;
 479   virtual void printsig (std::ostream &o) const = 0;
 480 };
 481
 482
 483 std::ostream& operator << (std::ostream& o, const symboldecl& k);
 484
 485
 486 struct vardecl: public symboldecl
 487 {
 488   void print (std::ostream& o) const;
 489   void printsig (std::ostream& o) const;
 490   vardecl ();
 491   void set_arity (int arity, const token* t);
 492   bool compatible_arity (int a);
 493   const token* arity_tok; // site where arity was first resolved
 494   int arity; // -1: unknown; 0: scalar; >0: array
 495   int maxsize; // upperbound on size for arrays
 496   std::vector<exp_type> index_types; // for arrays only
 497   literal *init; // for global scalars only
 498   bool skip_init; // for probe locals only, don't init on entry
 499   bool wrap;
 500 };
 501
 502
 503 struct vardecl_builtin: public vardecl
 504 {
 505 };
 506
 507
 508 struct statement;
 509 struct functiondecl: public symboldecl
 510 {
 511   std::vector<vardecl*> formal_args;
 512   std::vector<vardecl*> locals;
 513   std::vector<vardecl*> unused_locals;
 514   statement* body;
 515   bool synthetic;
 516   functiondecl ();
 517   void print (std::ostream& o) const;
 518   void printsig (std::ostream& o) const;
 519   void join (systemtap_session& s); // for synthetic functions only
 520 };
 521
 522
 523 // ------------------------------------------------------------------------
 524
 525
 526 struct statement
 527 {
 528   virtual void print (std::ostream& o) const = 0;
 529   virtual void visit (visitor* u) = 0;
 530   const token* tok;
 531   statement ();
 532   statement (const token* tok);
 533   virtual ~statement ();
 534 };
 535
 536 std::ostream& operator << (std::ostream& o, const statement& k);
 537
 538
 539 struct embeddedcode: public statement
 540 {
 541   std::string code;
 542   void print (std::ostream& o) const;
 543   void visit (visitor* u);
 544 };
 545
 546
 547 struct block: public statement
 548 {
 549   std::vector<statement*> statements;
 550   void print (std::ostream& o) const;
 551   void visit (visitor* u);
 552   block () {}
 553   block (statement* car, statement* cdr);
 554   virtual ~block () {}
 555 };
 556
 557
 558 struct try_block: public statement
 559 {
 560   statement* try_block; // may be 0
 561   statement* catch_block; // may be 0
 562   symbol* catch_error_var; // may be 0
 563   void print (std::ostream& o) const;
 564   void visit (visitor* u);
 565 };
 566
 567
 568 struct expr_statement;
 569 struct for_loop: public statement
 570 {
 571   expr_statement* init; // may be 0
 572   expression* cond;
 573   expr_statement* incr; // may be 0
 574   statement* block;
 575   void print (std::ostream& o) const;
 576   void visit (visitor* u);
 577 };
 578
 579
 580 struct foreach_loop: public statement
 581 {
 582   // this part is a specialization of arrayindex
 583   std::vector<symbol*> indexes;
 584   indexable *base;
 585   int sort_direction; // -1: decreasing, 0: none, 1: increasing
 586   unsigned sort_column; // 0: value, 1..N: index
 587   symbol* value; // optional iteration value
 588   expression* limit; // optional iteration limit
 589
 590   statement* block;
 591   void print (std::ostream& o) const;
 592   void visit (visitor* u);
 593 };
 594
 595
 596 struct null_statement: public statement
 597 {
 598   void print (std::ostream& o) const;
 599   void visit (visitor* u);
 600   null_statement (const token* tok);
 601 };
 602
 603
 604 struct expr_statement: public statement
 605 {
 606   expression* value;  // executed for side-effects
 607   void print (std::ostream& o) const;
 608   void visit (visitor* u);
 609 };
 610
 611
 612 struct if_statement: public statement
 613 {
 614   expression* condition;
 615   statement* thenblock;
 616   statement* elseblock; // may be 0
 617   void print (std::ostream& o) const;
 618   void visit (visitor* u);
 619 };
 620
 621
 622 struct return_statement: public expr_statement
 623 {
 624   void print (std::ostream& o) const;
 625   void visit (visitor* u);
 626 };
 627
 628
 629 struct delete_statement: public expr_statement
 630 {
 631   void print (std::ostream& o) const;
 632   void visit (visitor* u);
 633 };
 634
 635
 636 struct break_statement: public statement
 637 {
 638   void print (std::ostream& o) const;
 639   void visit (visitor* u);
 640 };
 641
 642
 643 struct continue_statement: public statement
 644 {
 645   void print (std::ostream& o) const;
 646   void visit (visitor* u);
 647 };
 648
 649
 650 struct next_statement: public statement
 651 {
 652   void print (std::ostream& o) const;
 653   void visit (visitor* u);
 654 };
 655
 656
 657 struct probe;
 658 struct derived_probe;
 659 struct probe_alias;
 660 struct embeddedcode;
 661 struct stapfile
 662 {
 663   std::string name;
 664   std::vector<probe*> probes;
 665   std::vector<probe_alias*> aliases;
 666   std::vector<functiondecl*> functions;
 667   std::vector<vardecl*> globals;
 668   std::vector<embeddedcode*> embeds;
 669   std::string file_contents;
 670   bool privileged;
 671   stapfile (): file_contents (""),
 672     privileged (false) {}
 673   void print (std::ostream& o) const;
 674 };
 675
 676
 677 struct probe_point
 678 {
 679   struct component // XXX: sort of a restricted functioncall
 680   {
 681     std::string functor;
 682     literal* arg; // optional
 683     component ();
 684     const token* tok; // points to component's functor
 685     component(std::string const & f, literal * a = NULL);
 686   };
 687   std::vector<component*> components;
 688   bool optional;
 689   bool sufficient;
 690   expression* condition;
 691   void print (std::ostream& o, bool print_extras=true) const;
 692   probe_point ();
 693   probe_point(const probe_point& pp);
 694   probe_point(std::vector<component*> const & comps);
 695   std::string str(bool print_extras=true) const;
 696 };
 697
 698 std::ostream& operator << (std::ostream& o, const probe_point& k);
 699
 700
 701 struct probe
 702 {
 703   std::vector<probe_point*> locations;
 704   statement* body;
 705   const token* tok;
 706   const token* systemtap_v_conditional; //checking systemtap compatibility
 707   std::vector<vardecl*> locals;
 708   std::vector<vardecl*> unused_locals;
 709   static unsigned last_probeidx;
 710   probe ();
 711   probe (const probe& p, probe_point *l);
 712   void print (std::ostream& o) const;
 713   virtual void printsig (std::ostream &o) const;
 714   virtual void collect_derivation_chain (std::vector<probe*> &probes_list);
 715   virtual void collect_derivation_pp_chain (std::vector<probe_point*> &) {}
 716   virtual const probe_alias *get_alias () const { return 0; }
 717   virtual probe* create_alias(probe_point* l, probe_point* a);
 718   virtual const probe* basest () const { return this; }
 719   virtual const probe* almost_basest () const { return 0; }
 720   virtual ~probe() {}
 721   bool privileged;
 722   std::string name;
 723 };
 724
 725 struct probe_alias: public probe
 726 {
 727   probe_alias(std::vector<probe_point*> const & aliases);
 728   std::vector<probe_point*> alias_names;
 729   virtual void printsig (std::ostream &o) const;
 730   bool epilogue_style;
 731 };
 732
 733
 734 // A derived visitor instance is used to visit the entire
 735 // statement/expression tree.
 736 struct visitor
 737 {
 738   // Machinery for differentiating lvalue visits from non-lvalue.
 739   std::vector<expression *> active_lvalues;
 740   bool is_active_lvalue(expression *e);
 741   void push_active_lvalue(expression *e);
 742   void pop_active_lvalue();
 743
 744   virtual ~visitor () {}
 745   virtual void visit_block (block *s) = 0;
 746   virtual void visit_try_block (try_block *s) = 0;
 747   virtual void visit_embeddedcode (embeddedcode *s) = 0;
 748   virtual void visit_null_statement (null_statement *s) = 0;
 749   virtual void visit_expr_statement (expr_statement *s) = 0;
 750   virtual void visit_if_statement (if_statement* s) = 0;
 751   virtual void visit_for_loop (for_loop* s) = 0;
 752   virtual void visit_foreach_loop (foreach_loop* s) = 0;
 753   virtual void visit_return_statement (return_statement* s) = 0;
 754   virtual void visit_delete_statement (delete_statement* s) = 0;
 755   virtual void visit_next_statement (next_statement* s) = 0;
 756   virtual void visit_break_statement (break_statement* s) = 0;
 757   virtual void visit_continue_statement (continue_statement* s) = 0;
 758   virtual void visit_literal_string (literal_string* e) = 0;
 759   virtual void visit_literal_number (literal_number* e) = 0;
 760   virtual void visit_embedded_expr (embedded_expr* e) = 0;
 761   virtual void visit_binary_expression (binary_expression* e) = 0;
 762   virtual void visit_unary_expression (unary_expression* e) = 0;
 763   virtual void visit_pre_crement (pre_crement* e) = 0;
 764   virtual void visit_post_crement (post_crement* e) = 0;
 765   virtual void visit_logical_or_expr (logical_or_expr* e) = 0;
 766   virtual void visit_logical_and_expr (logical_and_expr* e) = 0;
 767   virtual void visit_array_in (array_in* e) = 0;
 768   virtual void visit_comparison (comparison* e) = 0;
 769   virtual void visit_concatenation (concatenation* e) = 0;
 770   virtual void visit_ternary_expression (ternary_expression* e) = 0;
 771   virtual void visit_assignment (assignment* e) = 0;
 772   virtual void visit_symbol (symbol* e) = 0;
 773   virtual void visit_target_symbol (target_symbol* e) = 0;
 774   virtual void visit_arrayindex (arrayindex* e) = 0;
 775   virtual void visit_functioncall (functioncall* e) = 0;
 776   virtual void visit_print_format (print_format* e) = 0;
 777   virtual void visit_stat_op (stat_op* e) = 0;
 778   virtual void visit_hist_op (hist_op* e) = 0;
 779   virtual void visit_cast_op (cast_op* e) = 0;
 780   virtual void visit_defined_op (defined_op* e) = 0;
 781   virtual void visit_entry_op (entry_op* e) = 0;
 782 };
 783
 784
 785 // A simple kind of visitor, which travels down to the leaves of the
 786 // statement/expression tree, up to but excluding following vardecls
 787 // and functioncalls.
 788 struct traversing_visitor: public visitor
 789 {
 790   void visit_block (block *s);
 791   void visit_try_block (try_block *s);
 792   void visit_embeddedcode (embeddedcode *s);
 793   void visit_null_statement (null_statement *s);
 794   void visit_expr_statement (expr_statement *s);
 795   void visit_if_statement (if_statement* s);
 796   void visit_for_loop (for_loop* s);
 797   void visit_foreach_loop (foreach_loop* s);
 798   void visit_return_statement (return_statement* s);
 799   void visit_delete_statement (delete_statement* s);
 800   void visit_next_statement (next_statement* s);
 801   void visit_break_statement (break_statement* s);
 802   void visit_continue_statement (continue_statement* s);
 803   void visit_literal_string (literal_string* e);
 804   void visit_literal_number (literal_number* e);
 805   void visit_embedded_expr (embedded_expr* e);
 806   void visit_binary_expression (binary_expression* e);
 807   void visit_unary_expression (unary_expression* e);
 808   void visit_pre_crement (pre_crement* e);
 809   void visit_post_crement (post_crement* e);
 810   void visit_logical_or_expr (logical_or_expr* e);
 811   void visit_logical_and_expr (logical_and_expr* e);
 812   void visit_array_in (array_in* e);
 813   void visit_comparison (comparison* e);
 814   void visit_concatenation (concatenation* e);
 815   void visit_ternary_expression (ternary_expression* e);
 816   void visit_assignment (assignment* e);
 817   void visit_symbol (symbol* e);
 818   void visit_target_symbol (target_symbol* e);
 819   void visit_arrayindex (arrayindex* e);
 820   void visit_functioncall (functioncall* e);
 821   void visit_print_format (print_format* e);
 822   void visit_stat_op (stat_op* e);
 823   void visit_hist_op (hist_op* e);
 824   void visit_cast_op (cast_op* e);
 825   void visit_defined_op (defined_op* e);
 826   void visit_entry_op (entry_op* e);
 827 };
 828
 829
 830 // A kind of traversing visitor, which also follows function calls.
 831 // It uses an internal set object to prevent infinite recursion.
 832 struct functioncall_traversing_visitor: public traversing_visitor
 833 {
 834   std::set<functiondecl*> traversed;
 835   functiondecl* current_function;
 836   functioncall_traversing_visitor(): current_function(0) {}
 837   void visit_functioncall (functioncall* e);
 838 };
 839
 840
 841 // A kind of traversing visitor, which also follows function calls,
 842 // and stores the vardecl* referent of each variable read and/or
 843 // written and other such sundry side-effect data.  It's used by
 844 // the elaboration-time optimizer pass.
 845 struct varuse_collecting_visitor: public functioncall_traversing_visitor
 846 {
 847   systemtap_session& session;
 848   std::set<vardecl*> read;
 849   std::set<vardecl*> written;
 850   std::set<vardecl*> used;
 851   bool embedded_seen;
 852   bool current_lvalue_read;
 853   expression* current_lvalue;
 854   expression* current_lrvalue;
 855   varuse_collecting_visitor(systemtap_session& s):
 856     session (s),
 857     embedded_seen (false),
 858     current_lvalue_read (false),
 859     current_lvalue(0),
 860     current_lrvalue(0) {}
 861   void visit_embeddedcode (embeddedcode *s);
 862   void visit_embedded_expr (embedded_expr *e);
 863   void visit_try_block (try_block *s);
 864   void visit_delete_statement (delete_statement *s);
 865   void visit_print_format (print_format *e);
 866   void visit_assignment (assignment *e);
 867   void visit_arrayindex (arrayindex *e);
 868   void visit_target_symbol (target_symbol *e);
 869   void visit_symbol (symbol *e);
 870   void visit_pre_crement (pre_crement *e);
 871   void visit_post_crement (post_crement *e);
 872   void visit_foreach_loop (foreach_loop *s);
 873   void visit_cast_op (cast_op* e);
 874   void visit_defined_op (defined_op* e);
 875   void visit_entry_op (entry_op* e);
 876
 877   bool side_effect_free ();
 878   bool side_effect_free_wrt (const std::set<vardecl*>& vars);
 879 };
 880
 881
 882
 883 // A kind of visitor that throws an semantic_error exception
 884 // whenever a non-overridden method is called.
 885 struct throwing_visitor: public visitor
 886 {
 887   std::string msg;
 888   throwing_visitor (const std::string& m);
 889   throwing_visitor ();
 890
 891   virtual void throwone (const token* t);
 892
 893   void visit_block (block *s);
 894   void visit_try_block (try_block *s);
 895   void visit_embeddedcode (embeddedcode *s);
 896   void visit_null_statement (null_statement *s);
 897   void visit_expr_statement (expr_statement *s);
 898   void visit_if_statement (if_statement* s);
 899   void visit_for_loop (for_loop* s);
 900   void visit_foreach_loop (foreach_loop* s);
 901   void visit_return_statement (return_statement* s);
 902   void visit_delete_statement (delete_statement* s);
 903   void visit_next_statement (next_statement* s);
 904   void visit_break_statement (break_statement* s);
 905   void visit_continue_statement (continue_statement* s);
 906   void visit_literal_string (literal_string* e);
 907   void visit_literal_number (literal_number* e);
 908   void visit_embedded_expr (embedded_expr* e);
 909   void visit_binary_expression (binary_expression* e);
 910   void visit_unary_expression (unary_expression* e);
 911   void visit_pre_crement (pre_crement* e);
 912   void visit_post_crement (post_crement* e);
 913   void visit_logical_or_expr (logical_or_expr* e);
 914   void visit_logical_and_expr (logical_and_expr* e);
 915   void visit_array_in (array_in* e);
 916   void visit_comparison (comparison* e);
 917   void visit_concatenation (concatenation* e);
 918   void visit_ternary_expression (ternary_expression* e);
 919   void visit_assignment (assignment* e);
 920   void visit_symbol (symbol* e);
 921   void visit_target_symbol (target_symbol* e);
 922   void visit_arrayindex (arrayindex* e);
 923   void visit_functioncall (functioncall* e);
 924   void visit_print_format (print_format* e);
 925   void visit_stat_op (stat_op* e);
 926   void visit_hist_op (hist_op* e);
 927   void visit_cast_op (cast_op* e);
 928   void visit_defined_op (defined_op* e);
 929   void visit_entry_op (entry_op* e);
 930 };
 931
 932 // A visitor similar to a traversing_visitor, but with the ability to rewrite
 933 // parts of the tree through require/provide.
 934
 935 struct update_visitor: public visitor
 936 {
 937   template <typename T> T* require (T* src, bool clearok=false)
 938   {
 939     T* dst = NULL;
 940     if (src != NULL)
 941       {
 942         src->visit(this);
 943         assert(!targets.empty());
 944         dst = static_cast<T*>(targets.top()); // XXX: danger will robinson: not typesafe!
 945         targets.pop();
 946         assert(clearok || dst);
 947       }
 948     return dst;
 949   }
 950
 951   template <typename T> void provide (T* src)
 952   {
 953     targets.push(static_cast<void*>(src)); // XXX: not typesafe!
 954   }
 955
 956   template <typename T> void replace (T*& src, bool clearok=false)
 957   {
 958     src = require(src, clearok);
 959   }
 960
 961   virtual ~update_visitor() { assert(targets.empty()); }
 962
 963   virtual void visit_block (block *s);
 964   virtual void visit_try_block (try_block *s);
 965   virtual void visit_embeddedcode (embeddedcode *s);
 966   virtual void visit_null_statement (null_statement *s);
 967   virtual void visit_expr_statement (expr_statement *s);
 968   virtual void visit_if_statement (if_statement* s);
 969   virtual void visit_for_loop (for_loop* s);
 970   virtual void visit_foreach_loop (foreach_loop* s);
 971   virtual void visit_return_statement (return_statement* s);
 972   virtual void visit_delete_statement (delete_statement* s);
 973   virtual void visit_next_statement (next_statement* s);
 974   virtual void visit_break_statement (break_statement* s);
 975   virtual void visit_continue_statement (continue_statement* s);
 976   virtual void visit_literal_string (literal_string* e);
 977   virtual void visit_literal_number (literal_number* e);
 978   virtual void visit_embedded_expr (embedded_expr* e);
 979   virtual void visit_binary_expression (binary_expression* e);
 980   virtual void visit_unary_expression (unary_expression* e);
 981   virtual void visit_pre_crement (pre_crement* e);
 982   virtual void visit_post_crement (post_crement* e);
 983   virtual void visit_logical_or_expr (logical_or_expr* e);
 984   virtual void visit_logical_and_expr (logical_and_expr* e);
 985   virtual void visit_array_in (array_in* e);
 986   virtual void visit_comparison (comparison* e);
 987   virtual void visit_concatenation (concatenation* e);
 988   virtual void visit_ternary_expression (ternary_expression* e);
 989   virtual void visit_assignment (assignment* e);
 990   virtual void visit_symbol (symbol* e);
 991   virtual void visit_target_symbol (target_symbol* e);
 992   virtual void visit_arrayindex (arrayindex* e);
 993   virtual void visit_functioncall (functioncall* e);
 994   virtual void visit_print_format (print_format* e);
 995   virtual void visit_stat_op (stat_op* e);
 996   virtual void visit_hist_op (hist_op* e);
 997   virtual void visit_cast_op (cast_op* e);
 998   virtual void visit_defined_op (defined_op* e);
 999   virtual void visit_entry_op (entry_op* e);
1000
1001 private:
1002   std::stack<void *> targets;
1003 };
1004
1005 template <> indexable*
1006 update_visitor::require <indexable> (indexable* src, bool clearok);
1007
1008 // A visitor which performs a deep copy of the root node it's applied
1009 // to. NB: It does not copy any of the variable or function
1010 // declarations; those fields are set to NULL, assuming you want to
1011 // re-infer the declarations in a new context (the one you're copying
1012 // to).
1013
1014 struct deep_copy_visitor: public update_visitor
1015 {
1016   template <typename T> static T* deep_copy (T* e)
1017   {
1018     deep_copy_visitor v;
1019     return v.require (e);
1020   }
1021
1022   virtual void visit_block (block *s);
1023   virtual void visit_try_block (try_block *s);
1024   virtual void visit_embeddedcode (embeddedcode *s);
1025   virtual void visit_null_statement (null_statement *s);
1026   virtual void visit_expr_statement (expr_statement *s);
1027   virtual void visit_if_statement (if_statement* s);
1028   virtual void visit_for_loop (for_loop* s);
1029   virtual void visit_foreach_loop (foreach_loop* s);
1030   virtual void visit_return_statement (return_statement* s);
1031   virtual void visit_delete_statement (delete_statement* s);
1032   virtual void visit_next_statement (next_statement* s);
1033   virtual void visit_break_statement (break_statement* s);
1034   virtual void visit_continue_statement (continue_statement* s);
1035   virtual void visit_literal_string (literal_string* e);
1036   virtual void visit_literal_number (literal_number* e);
1037   virtual void visit_embedded_expr (embedded_expr* e);
1038   virtual void visit_binary_expression (binary_expression* e);
1039   virtual void visit_unary_expression (unary_expression* e);
1040   virtual void visit_pre_crement (pre_crement* e);
1041   virtual void visit_post_crement (post_crement* e);
1042   virtual void visit_logical_or_expr (logical_or_expr* e);
1043   virtual void visit_logical_and_expr (logical_and_expr* e);
1044   virtual void visit_array_in (array_in* e);
1045   virtual void visit_comparison (comparison* e);
1046   virtual void visit_concatenation (concatenation* e);
1047   virtual void visit_ternary_expression (ternary_expression* e);
1048   virtual void visit_assignment (assignment* e);
1049   virtual void visit_symbol (symbol* e);
1050   virtual void visit_target_symbol (target_symbol* e);
1051   virtual void visit_arrayindex (arrayindex* e);
1052   virtual void visit_functioncall (functioncall* e);
1053   virtual void visit_print_format (print_format* e);
1054   virtual void visit_stat_op (stat_op* e);
1055   virtual void visit_hist_op (hist_op* e);
1056   virtual void visit_cast_op (cast_op* e);
1057   virtual void visit_defined_op (defined_op* e);
1058   virtual void visit_entry_op (entry_op* e);
1059 };
1060
1061 #endif // STAPTREE_H
1062
1063 /* vim: set sw=2 ts=8 cino=>4,n-2,{2,^-2,t0,(0,u0,w1,M1 : */