| 1 | (* Yoann Padioleau |
| 2 | * |
| 3 | * Copyright (C) 2006, 2007, 2008 Ecole des Mines de Nantes |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License (GPL) |
| 7 | * version 2 as published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * file license.txt for more details. |
| 13 | *) |
| 14 | open Common |
| 15 | |
| 16 | open Ast_c |
| 17 | |
| 18 | (*****************************************************************************) |
| 19 | (* |
| 20 | * There is more information in the CFG we build that in the CFG usually built |
| 21 | * in a compiler. This is because: |
| 22 | * |
| 23 | * - We need later to go back from flow to original ast, because we are |
| 24 | * doing a refactoring tool, so different context. So we have to add |
| 25 | * some nodes for '{' or '}' or goto that normally disapear in a CFG. |
| 26 | * We must keep those entities, in the same way that we must keep the parens |
| 27 | * (ParenExpr, ParenType) in the Ast_c during parsing. |
| 28 | * |
| 29 | * Moreover, the coccier can mention in his semantic patch those entities, |
| 30 | * so we must keep those entities in the CFG. |
| 31 | * |
| 32 | * We also have to add some extra nodes to make the process that goes from |
| 33 | * flow to ast deterministic with for instance the CaseNode, or easier |
| 34 | * with for instance the Fake node. |
| 35 | * |
| 36 | * - The coccinelle engine later transforms some nodes, and we need to rebuild |
| 37 | * the ast from a statement now defined and altered in different nodes. |
| 38 | * So we can't just put all the parsing info (Ast_c.il) in the top node of |
| 39 | * a statement. We have to split those Ast_c.il in different nodes, to |
| 40 | * later reconstruct a full Ast_c.il from different nodes. This is why |
| 41 | * we need the Else node, ... |
| 42 | * |
| 43 | * Note that at the same time, we also need to store the fullstatement |
| 44 | * in the top node, because the CTL engine need to get that information |
| 45 | * when dealing with MetaStatement (statement S; in a Semantic Patch). |
| 46 | * |
| 47 | * |
| 48 | * - The CTL engine needs more information than just the CFG, and we use |
| 49 | * tricks to encode those informations in the nodes: |
| 50 | * |
| 51 | * - We have some TrueNode, FalseNode to know in what branch we are. |
| 52 | * Normally we could achieve this by putting this information in the |
| 53 | * edges, but CTL engine know nothing about edges, it must do |
| 54 | * everything with only nodes information. |
| 55 | * |
| 56 | * - We need to mark each braces with an identifier so that the CTL |
| 57 | * can know if one specific '}' correspond to a specific '{'. |
| 58 | * |
| 59 | * - We add some labels to each node to handle the MetaRuleElem and |
| 60 | * MetaStatement. It allows to groups nodes that belong to the same |
| 61 | * statement. Normally CFG are there to abstract from this, but in |
| 62 | * Coccinelle we need sometimes the CFG view, and sometimes the Ast |
| 63 | * view and the labels allow that. |
| 64 | * |
| 65 | * - We even add nodes. We add '}', not only to be able to go back to AST |
| 66 | * but also because of the CTL engine. So one '}' may in fact be |
| 67 | * represented by multiple nodes, one in each CFG path. |
| 68 | * |
| 69 | * - need After, |
| 70 | * - need FallThrough. |
| 71 | * - Need know if ErrorExit, |
| 72 | * |
| 73 | * choice: Julia proposed that the flow is in fact just |
| 74 | * a view through the Ast, which means just Ocaml ref, so that when we |
| 75 | * modify some nodes, in fact it modifies the ast. But I prefer do it |
| 76 | * the functionnal way. |
| 77 | * |
| 78 | * The node2 type should be as close as possible to Ast_cocci.rule_elem to |
| 79 | * facilitate the job of cocci_vs_c. |
| 80 | * |
| 81 | *) |
| 82 | |
| 83 | (*****************************************************************************) |
| 84 | |
| 85 | |
| 86 | (* ---------------------------------------------------------------------- *) |
| 87 | (* The string is for debugging. Used by Ograph_extended.print_graph. |
| 88 | * The int list are Labels. Trick used for CTL engine. Must not |
| 89 | * transform that in a triple or record because print_graph would |
| 90 | * not work. |
| 91 | *) |
| 92 | type node = node1 * string |
| 93 | and node1 = node2 * nodeinfo |
| 94 | and nodeinfo = { |
| 95 | labels: int list; |
| 96 | bclabels: int list; (* parent of a break or continue node *) |
| 97 | is_loop: bool; |
| 98 | is_fake: bool; |
| 99 | } |
| 100 | and node2 = |
| 101 | |
| 102 | (* ------------------------ *) |
| 103 | (* For CTL to work, we need that some nodes loop over itself. We |
| 104 | * need that every nodes have a successor. Julia also want to go back |
| 105 | * indefinitely. So must tag some nodes as the beginning and end of |
| 106 | * the graph so that some fix_ctl function can easily find those |
| 107 | * nodes. |
| 108 | * |
| 109 | * If have a function, then no need for EndNode; Exit and ErrorExit |
| 110 | * will play that role. |
| 111 | * |
| 112 | * When everything we analyze was a function there was no pb. We used |
| 113 | * FunHeader as a Topnode and Exit for EndNode but now that we also |
| 114 | * analyse #define body, so we need those nodes. |
| 115 | *) |
| 116 | | TopNode |
| 117 | | EndNode |
| 118 | |
| 119 | (* ------------------------ *) |
| 120 | | FunHeader of definition (* but empty body *) |
| 121 | |
| 122 | | Decl of declaration |
| 123 | |
| 124 | (* ------------------------ *) |
| 125 | (* flow_to_ast: cocci: Need the { and } in the control flow graph also |
| 126 | * because the coccier can express patterns containing such { }. |
| 127 | * |
| 128 | * ctl: to make possible the forall (AX, A[...]), have to add more than |
| 129 | * one node sometimes for the same '}' (one in each CFG path) in the graph. |
| 130 | * |
| 131 | * ctl: Morover, the int in the type is here to indicate to what { } |
| 132 | * they correspond. Two pairwise { } share the same number. kind of |
| 133 | * "brace_identifier". Used for debugging or for checks and more importantly, |
| 134 | * needed by CTL engine. |
| 135 | * |
| 136 | * Because of those nodes, there is no equivalent for Compound. |
| 137 | * |
| 138 | * There was a problem with SeqEnd. Some info can be tagged on it |
| 139 | * but there is multiple SeqEnd that correspond to the same '}' even |
| 140 | * if they are in different nodes. Solved by using shared ref |
| 141 | * and allow the "already-tagged" token. |
| 142 | *) |
| 143 | | SeqStart of statement * int * info |
| 144 | | SeqEnd of int * info |
| 145 | |
| 146 | |
| 147 | | ExprStatement of statement * (expression option) wrap |
| 148 | |
| 149 | |
| 150 | | IfHeader of statement * expression wrap |
| 151 | | Else of info |
| 152 | | WhileHeader of statement * expression wrap |
| 153 | | DoHeader of statement * info |
| 154 | | DoWhileTail of expression wrap |
| 155 | | ForHeader of statement * |
| 156 | (exprStatement wrap * exprStatement wrap * exprStatement wrap) |
| 157 | wrap |
| 158 | | SwitchHeader of statement * expression wrap |
| 159 | | MacroIterHeader of statement * (string * argument wrap2 list) wrap |
| 160 | |
| 161 | (* Used to mark the end of if, while, dowhile, for, switch. Later we |
| 162 | * will be able to "tag" some cocci code on this node. |
| 163 | * |
| 164 | * This is because in |
| 165 | * |
| 166 | * - S + foo(); |
| 167 | * |
| 168 | * the S can be anything, including an if, and this is internally |
| 169 | * translated in a series of MetaRuleElem, and the last element is a |
| 170 | * EndStatement, and we must tag foo() to this EndStatement. |
| 171 | * Otherwise, without this last common node, we would tag foo() to 2 |
| 172 | * nodes :( So having a unique node makes it correct, and in |
| 173 | * flow_to_ast we must propagate back this + foo() to the last token |
| 174 | * of an if (maybe a '}', maybe a ';') |
| 175 | * |
| 176 | * The problem is that this stuff should be in transformation.ml, |
| 177 | * but need information available in flow_to_ast, but we dont want |
| 178 | * to polluate both files. |
| 179 | * |
| 180 | * So the choices are |
| 181 | * |
| 182 | * - soluce julia1, extend Ast_c by adding a fake token to the if |
| 183 | * |
| 184 | * - extend Ast with a Skip, and add this next to EndStatement node, |
| 185 | * and do special case in flow_to_ast to start from this node |
| 186 | * (not to get_next EndStatement, but from EndStatement directly) |
| 187 | * and so add a case when have directly a EndStatement node an extract |
| 188 | * the statement from it. |
| 189 | * |
| 190 | * - remonter dans le graphe pour accrocher le foo() non plus au |
| 191 | * EndStatement (qui n'a pas d'equivalent niveau token dans l'ast_c), |
| 192 | * mais au dernier token de la branche Else (ou Then si y'a pas de else). |
| 193 | * |
| 194 | * I first did solution 2 and then when we decided to use ref, |
| 195 | * I use julia'as solution. Have virtual-placeholders, the fakeInfo |
| 196 | * for the if, while, and put this shared ref in the EndStatement. |
| 197 | *) |
| 198 | | EndStatement of info option (* fake_info *) |
| 199 | |
| 200 | | Return of statement * unit wrap |
| 201 | | ReturnExpr of statement * expression wrap |
| 202 | |
| 203 | (* ------------------------ *) |
| 204 | | IfdefHeader of ifdef_directive |
| 205 | | IfdefElse of ifdef_directive |
| 206 | | IfdefEndif of ifdef_directive |
| 207 | |
| 208 | |
| 209 | (* ------------------------ *) |
| 210 | | DefineHeader of string wrap * define_kind |
| 211 | |
| 212 | | DefineExpr of expression |
| 213 | | DefineType of fullType |
| 214 | | DefineDoWhileZeroHeader of unit wrap |
| 215 | | DefineTodo |
| 216 | |
| 217 | | Include of includ |
| 218 | |
| 219 | (* obsolete? *) |
| 220 | | MacroTop of string * argument wrap2 list * il |
| 221 | |
| 222 | (* ------------------------ *) |
| 223 | | Case of statement * expression wrap |
| 224 | | Default of statement * unit wrap |
| 225 | |
| 226 | | Continue of statement * unit wrap |
| 227 | | Break of statement * unit wrap |
| 228 | |
| 229 | (* no counter part in cocci *) |
| 230 | | CaseRange of statement * (expression * expression) wrap |
| 231 | | Label of statement * string wrap |
| 232 | | Goto of statement * string wrap |
| 233 | |
| 234 | |
| 235 | | Asm of statement * asmbody wrap |
| 236 | | MacroStmt of statement * unit wrap |
| 237 | |
| 238 | (* ------------------------ *) |
| 239 | (* some control nodes *) |
| 240 | | Enter |
| 241 | | Exit |
| 242 | |
| 243 | |
| 244 | (* Redundant nodes, often to mark the end of an if/switch. |
| 245 | * That makes it easier to do later the flow_to_ast. |
| 246 | * update: no more used for the end. see Endstatement. Just used |
| 247 | * to mark the start of the function, as required by julia. |
| 248 | * Maybe would be better to use instead a Enter2. |
| 249 | *) |
| 250 | | Fake |
| 251 | |
| 252 | (* flow_to_ast: In this case, I need to know the order between the children |
| 253 | * of the switch in the graph. |
| 254 | *) |
| 255 | | CaseNode of int |
| 256 | |
| 257 | (* ------------------------ *) |
| 258 | (* for ctl: *) |
| 259 | | TrueNode |
| 260 | | FalseNode |
| 261 | | InLoopNode (* almost equivalent to TrueNode but just for loops *) |
| 262 | |
| 263 | | AfterNode |
| 264 | | FallThroughNode |
| 265 | |
| 266 | | ErrorExit |
| 267 | |
| 268 | type edge = Direct (* Normal | Shadow *) |
| 269 | |
| 270 | type cflow = (node, edge) Ograph_extended.ograph_mutable |
| 271 | |
| 272 | |
| 273 | (* ------------------------------------------------------------------------ *) |
| 274 | let unwrap ((node, info), nodestr) = node |
| 275 | let rewrap ((_node, info), nodestr) node = (node, info), nodestr |
| 276 | let extract_labels ((node, info), nodestr) = info.labels |
| 277 | let extract_bclabels ((node, info), nodestr) = info.bclabels |
| 278 | let extract_is_loop ((node, info), nodestr) = info.is_loop |
| 279 | let extract_is_fake ((node, info), nodestr) = info.is_fake |
| 280 | |
| 281 | let mk_any_node is_fake node labels bclabels nodestr = |
| 282 | let nodestr = |
| 283 | if !Flag_parsing_c.show_flow_labels |
| 284 | then nodestr ^ ("[" ^ (labels +> List.map i_to_s +> join ",") ^ "]") |
| 285 | else nodestr |
| 286 | in |
| 287 | ((node, {labels = labels;is_loop=false;bclabels=bclabels;is_fake=is_fake}), |
| 288 | nodestr) |
| 289 | |
| 290 | let mk_node = mk_any_node false |
| 291 | let mk_fake_node = mk_any_node true (* for duplicated braces *) |
| 292 | |
| 293 | (* ------------------------------------------------------------------------ *) |
| 294 | let first_node g = |
| 295 | g#nodes#tolist +> List.find (fun (i, node) -> |
| 296 | match unwrap node with TopNode -> true | _ -> false |
| 297 | ) +> fst |
| 298 | |
| 299 | let find_node f g = |
| 300 | g#nodes#tolist +> List.find (fun (nodei, node) -> |
| 301 | f (unwrap node)) |
| 302 | +> fst |
| 303 | |
| 304 | |
| 305 | (* remove an intermediate node and redirect the connexion *) |
| 306 | let remove_one_node nodei g = |
| 307 | let preds = (g#predecessors nodei)#tolist in |
| 308 | let succs = (g#successors nodei)#tolist in |
| 309 | assert (not (null preds)); |
| 310 | |
| 311 | preds +> List.iter (fun (predi, Direct) -> |
| 312 | g#del_arc ((predi, nodei), Direct); |
| 313 | ); |
| 314 | succs +> List.iter (fun (succi, Direct) -> |
| 315 | g#del_arc ((nodei, succi), Direct); |
| 316 | ); |
| 317 | |
| 318 | g#del_node nodei; |
| 319 | |
| 320 | (* connect in-nodes to out-nodes *) |
| 321 | preds +> List.iter (fun (pred, Direct) -> |
| 322 | succs +> List.iter (fun (succ, Direct) -> |
| 323 | g#add_arc ((pred, succ), Direct); |
| 324 | ); |
| 325 | ) |
| 326 | |
| 327 | |
| 328 | |
| 329 | (* ------------------------------------------------------------------------ *) |
| 330 | |
| 331 | let extract_fullstatement node = |
| 332 | match unwrap node with |
| 333 | | Decl decl -> |
| 334 | (* new policy. no more considered as a statement *) |
| 335 | (* old: Some (Ast_c.Decl decl, []) *) |
| 336 | None |
| 337 | | MacroStmt (st, _) -> Some st |
| 338 | | MacroIterHeader (st, _) -> Some st |
| 339 | |
| 340 | | Include _ |
| 341 | | DefineHeader _ | DefineType _ | DefineExpr _ | DefineDoWhileZeroHeader _ |
| 342 | | DefineTodo |
| 343 | | MacroTop _ |
| 344 | -> None |
| 345 | |
| 346 | | IfdefHeader _ | IfdefElse _ | IfdefEndif _ |
| 347 | -> None |
| 348 | |
| 349 | | SeqStart (st,_,_) |
| 350 | | ExprStatement (st, _) |
| 351 | | IfHeader (st, _) |
| 352 | | WhileHeader (st, _) |
| 353 | | DoHeader (st, _) |
| 354 | | ForHeader (st, _) |
| 355 | | SwitchHeader (st, _) |
| 356 | | Return (st, _) |
| 357 | | ReturnExpr (st, _) |
| 358 | (* no counter part in cocci *) |
| 359 | | Label (st, _) |
| 360 | | Case (st,_) |
| 361 | | CaseRange (st, _) |
| 362 | | Default (st, _) |
| 363 | | Goto (st, _) |
| 364 | | Continue (st, _) |
| 365 | | Break (st, _) |
| 366 | | Asm (st,_) |
| 367 | -> Some st |
| 368 | |
| 369 | | TopNode|EndNode |
| 370 | | FunHeader _ |
| 371 | | SeqEnd _ |
| 372 | | Else _ |
| 373 | | EndStatement _ |
| 374 | | DoWhileTail _ |
| 375 | | Enter |
| 376 | | Exit |
| 377 | | Fake |
| 378 | | CaseNode _ |
| 379 | | TrueNode |
| 380 | | FalseNode |
| 381 | | InLoopNode |
| 382 | | AfterNode |
| 383 | | FallThroughNode |
| 384 | | ErrorExit |
| 385 | -> None |