filter/decl.m4

   1 m4_divert(-1)m4_dnl
   2 #
   3 #       BIRD -- Construction of per-instruction structures
   4 #
   5 #       (c) 2018 Maria Matejka <mq@jmq.cz>
   6 #
   7 #       Can be freely distributed and used under the terms of the GNU GPL.
   8 #
   9 #       THIS IS A M4 MACRO FILE GENERATING 3 FILES ALTOGETHER.
  10 #       KEEP YOUR HANDS OFF UNLESS YOU KNOW WHAT YOU'RE DOING.
  11 #       EDITING AND DEBUGGING THIS FILE MAY DAMAGE YOUR BRAIN SERIOUSLY.
  12 #
  13 #       But you're welcome to read and edit and debug if you aren't scared.
  14 #
  15 #       Uncomment the following line to get exhaustive debug output.
  16 #       m4_debugmode(aceflqtx)
  17 #
  18 #       How it works:
  19 #       1) Instruction to code conversion (uses diversions 100..199)
  20 #       2) Code wrapping (uses diversions 1..99)
  21 #       3) Final preparation (uses diversions 200..299)
  22 #       4) Shipout
  23 #
  24 #       See below for detailed description.
  25 #
  26 #
  27 #       1) Instruction to code conversion
  28 #       The code provided in f-inst.c between consecutive INST() calls
  29 #       is interleaved for many different places. It is here processed
  30 #       and split into separate instances where split-by-instruction
  31 #       happens. These parts are stored in temporary diversions listed:
  32 #
  33 #       101     content of per-inst struct
  34 #       102     constructor arguments
  35 #       103     constructor body
  36 #       104     dump line item content
  37 #               (there may be nothing in dump-line content and
  38 #                it must be handled specially in phase 2)
  39 #       105     linearize body
  40 #       106     comparator body
  41 #       107     struct f_line_item content
  42 #       108     interpreter body
  43 #       109     iterator body
  44 #
  45 #       Here are macros to allow you to _divert to the right directions.
  46 m4_define(FID_STRUCT_IN, `m4_divert(101)')
  47 m4_define(FID_NEW_ARGS, `m4_divert(102)')
  48 m4_define(FID_NEW_BODY, `m4_divert(103)')
  49 m4_define(FID_DUMP_BODY, `m4_divert(104)m4_define([[FID_DUMP_BODY_EXISTS]])')
  50 m4_define(FID_LINEARIZE_BODY, `m4_divert(105)')
  51 m4_define(FID_SAME_BODY, `m4_divert(106)')
  52 m4_define(FID_LINE_IN, `m4_divert(107)')
  53 m4_define(FID_INTERPRET_BODY, `m4_divert(108)')
  54 m4_define(FID_ITERATE_BODY, `m4_divert(109)')
  55
  56 #       Sometimes you want slightly different code versions in different
  57 #       outputs.
  58 #       Use FID_HIC(code for inst-gen.h, code for inst-gen.c, code for inst-interpret.c)
  59 #       and put it into [[ ]] quotes if it shall contain commas.
  60 m4_define(FID_HIC, `m4_ifelse(TARGET, [[H]], [[$1]], TARGET, [[I]], [[$2]], TARGET, [[C]], [[$3]])')
  61
  62 #       In interpreter code, this is quite common.
  63 m4_define(FID_INTERPRET_EXEC, `FID_HIC(,[[FID_INTERPRET_BODY()]],[[m4_divert(-1)]])')
  64 m4_define(FID_INTERPRET_NEW,  `FID_HIC(,[[m4_divert(-1)]],[[FID_INTERPRET_BODY()]])')
  65
  66 #       If the instruction is never converted to constant, the interpret
  67 #       code is not produced at all for constructor
  68 m4_define(NEVER_CONSTANT, `m4_define([[INST_NEVER_CONSTANT]])')
  69 m4_define(FID_IFCONST, `m4_ifdef([[INST_NEVER_CONSTANT]],[[$2]],[[$1]])')
  70
  71 #       If the instruction has some attributes (here called members),
  72 #       these are typically carried with the instruction from constructor
  73 #       to interpreter. This yields a line of code everywhere on the path.
  74 #       FID_MEMBER is a macro to help with this task.
  75 m4_define(FID_MEMBER, `m4_dnl
  76 FID_LINE_IN()m4_dnl
  77       $1 $2;
  78 FID_STRUCT_IN()m4_dnl
  79       $1 $2;
  80 FID_NEW_ARGS()m4_dnl
  81   , $1 $2
  82 FID_NEW_BODY()m4_dnl
  83 whati->$2 = $2;
  84 FID_LINEARIZE_BODY()m4_dnl
  85 item->$2 = whati->$2;
  86 m4_ifelse($3,,,[[
  87 FID_SAME_BODY()m4_dnl
  88 if ($3) return 0;
  89 ]])
  90 m4_ifelse($4,,,[[
  91 FID_DUMP_BODY()m4_dnl
  92 debug("%s" $4 "\n", INDENT, $5);
  93 ]])
  94 FID_INTERPRET_EXEC()m4_dnl
  95 const $1 $2 = whati->$2
  96 FID_INTERPRET_BODY')
  97
  98 #       Instruction arguments are needed only until linearization is done.
  99 #       This puts the arguments into the filter line to be executed before
 100 #       the instruction itself.
 101 #
 102 #       To achieve this, ARG_ANY must be called before anything writes into
 103 #       the instruction line as it moves the instruction pointer forward.
 104 m4_define(ARG_ANY, `
 105 FID_STRUCT_IN()m4_dnl
 106       struct f_inst * f$1;
 107 FID_NEW_ARGS()m4_dnl
 108   , struct f_inst * f$1
 109 FID_NEW_BODY()m4_dnl
 110 whati->f$1 = f$1;
 111 for (const struct f_inst *child = f$1; child; child = child->next) {
 112   what->size += child->size;
 113 FID_IFCONST([[
 114   if (child->fi_code != FI_CONSTANT)
 115     constargs = 0;
 116 ]])
 117 }
 118 FID_LINEARIZE_BODY
 119 pos = linearize(dest, whati->f$1, pos);
 120 FID_INTERPRET_BODY()')
 121
 122 #       Some instructions accept variable number of arguments.
 123 m4_define(VARARG, `
 124 FID_NEW_ARGS()m4_dnl
 125   , struct f_inst * fvar
 126 FID_STRUCT_IN()m4_dnl
 127       struct f_inst * fvar;
 128       uint varcount;
 129 FID_LINE_IN()m4_dnl
 130       uint varcount;
 131 FID_NEW_BODY()m4_dnl
 132 whati->varcount = 0;
 133 whati->fvar = fvar;
 134 for (const struct f_inst *child = fvar; child; child = child->next, whati->varcount++) {
 135   what->size += child->size;
 136 FID_IFCONST([[
 137   if (child->fi_code != FI_CONSTANT)
 138     constargs = 0;
 139 ]])
 140 }
 141 FID_IFCONST([[
 142   const struct f_inst **items = NULL;
 143   if (constargs && whati->varcount) {
 144     items = alloca(whati->varcount * sizeof(struct f_inst *));
 145     const struct f_inst *child = fvar;
 146     for (uint i=0; child; i++)
 147       child = (items[i] = child)->next;
 148   }
 149 ]])
 150 FID_LINEARIZE_BODY()m4_dnl
 151   pos = linearize(dest, whati->fvar, pos);
 152   item->varcount = whati->varcount;
 153 FID_DUMP_BODY()m4_dnl
 154   debug("%snumber of varargs %u\n", INDENT, item->varcount);
 155 FID_SAME_BODY()m4_dnl
 156   if (f1->varcount != f2->varcount) return 0;
 157 FID_INTERPRET_BODY()
 158 FID_HIC(,[[
 159   if (fstk->vcnt < whati->varcount) runtime("Stack underflow");
 160   fstk->vcnt -= whati->varcount;
 161 ]],)
 162 ')
 163
 164 #       Some arguments need to check their type. After that, ARG_ANY is called.
 165 m4_define(ARG, `ARG_ANY($1) ARG_TYPE($1,$2)')
 166 m4_define(ARG_TYPE, `ARG_TYPE_STATIC($1,$2) ARG_TYPE_DYNAMIC($1,$2)')
 167
 168 m4_define(ARG_TYPE_STATIC, `
 169 FID_NEW_BODY()m4_dnl
 170 if (f$1->type && (f$1->type != ($2)) && !f_const_promotion(f$1, ($2)))
 171   cf_error("Argument $1 of %s must be of type %s, got type %s",
 172            f_instruction_name(what->fi_code), f_type_name($2), f_type_name(f$1->type));
 173 FID_INTERPRET_BODY()')
 174
 175 m4_define(ARG_TYPE_DYNAMIC, `
 176 FID_INTERPRET_EXEC()m4_dnl
 177 if (v$1.type != ($2))
 178   runtime("Argument $1 of %s must be of type %s, got type %s",
 179            f_instruction_name(what->fi_code), f_type_name($2), f_type_name(v$1.type));
 180 FID_INTERPRET_BODY()')
 181
 182 m4_define(ARG_SAME_TYPE, `
 183 FID_NEW_BODY()m4_dnl
 184 if (f$1->type && f$2->type && (f$1->type != f$2->type) &&
 185    !f_const_promotion(f$2, f$1->type) && !f_const_promotion(f$1, f$2->type))
 186   cf_error("Arguments $1 and $2 of %s must be of the same type", f_instruction_name(what->fi_code));
 187 FID_INTERPRET_BODY()')
 188
 189 #       Executing another filter line. This replaces the recursion
 190 #       that was needed in the former implementation.
 191 m4_define(LINEX, `FID_INTERPRET_EXEC()LINEX_($1)FID_INTERPRET_NEW()return $1 FID_INTERPRET_BODY()')
 192 m4_define(LINEX_, `do {
 193   fstk->estk[fstk->ecnt].pos = 0;
 194   fstk->estk[fstk->ecnt].line = $1;
 195   fstk->estk[fstk->ecnt].ventry = fstk->vcnt;
 196   fstk->estk[fstk->ecnt].vbase = fstk->estk[fstk->ecnt-1].vbase;
 197   fstk->estk[fstk->ecnt].emask = 0;
 198   fstk->ecnt++;
 199 } while (0)')
 200
 201 m4_define(LINE, `
 202 FID_LINE_IN()m4_dnl
 203       const struct f_line * fl$1;
 204 FID_STRUCT_IN()m4_dnl
 205       struct f_inst * f$1;
 206 FID_NEW_ARGS()m4_dnl
 207   , struct f_inst * f$1
 208 FID_NEW_BODY()m4_dnl
 209 whati->f$1 = f$1;
 210 FID_DUMP_BODY()m4_dnl
 211 f_dump_line(item->fl$1, indent + 1);
 212 FID_LINEARIZE_BODY()m4_dnl
 213 item->fl$1 = f_linearize(whati->f$1);
 214 FID_SAME_BODY()m4_dnl
 215 if (!f_same(f1->fl$1, f2->fl$1)) return 0;
 216 FID_ITERATE_BODY()m4_dnl
 217 if (whati->fl$1) BUFFER_PUSH(fit->lines) = whati->fl$1;
 218 FID_INTERPRET_EXEC()m4_dnl
 219 do { if (whati->fl$1) {
 220   LINEX_(whati->fl$1);
 221 } } while(0)
 222 FID_INTERPRET_NEW()m4_dnl
 223 return whati->f$1
 224 FID_INTERPRET_BODY()')
 225
 226 #       Some of the instructions have a result. These constructions
 227 #       state the result and put it to the right place.
 228 m4_define(RESULT, `RESULT_TYPE([[$1]]) RESULT_([[$1]],[[$2]],[[$3]])')
 229 m4_define(RESULT_, `RESULT_VAL([[ (struct f_val) { .type = $1, .val.$2 = $3 } ]])')
 230 m4_define(RESULT_VAL, `FID_HIC(, [[do { res = $1; fstk->vcnt++; } while (0)]],
 231 [[return fi_constant(what, $1)]])')
 232 m4_define(RESULT_VOID, `RESULT_VAL([[ (struct f_val) { .type = T_VOID } ]])')
 233
 234 m4_define(ERROR,
 235        `m4_errprint(m4___file__:m4___line__: $*
 236        )m4_m4exit(1)')
 237
 238 #       This macro specifies result type and makes there are no conflicting definitions
 239 m4_define(RESULT_TYPE,
 240         `m4_ifdef([[INST_RESULT_TYPE]],
 241                   [[m4_ifelse(INST_RESULT_TYPE,$1,,[[ERROR([[Multiple type definitons]])]])]],
 242                   [[m4_define(INST_RESULT_TYPE,$1) RESULT_TYPE_($1)]])')
 243
 244 m4_define(RESULT_TYPE_, `
 245 FID_NEW_BODY()m4_dnl
 246 what->type = $1;
 247 FID_INTERPRET_BODY()')
 248
 249 #       Some common filter instruction members
 250 m4_define(SYMBOL, `FID_MEMBER(struct symbol *, sym, [[strcmp(f1->sym->name, f2->sym->name) || (f1->sym->class != f2->sym->class)]], "symbol %s", item->sym->name)')
 251 m4_define(RTC, `FID_MEMBER(struct rtable_config *, rtc, [[strcmp(f1->rtc->name, f2->rtc->name)]], "route table %s", item->rtc->name)')
 252 m4_define(STATIC_ATTR, `FID_MEMBER(struct f_static_attr, sa, f1->sa.sa_code != f2->sa.sa_code,,)')
 253 m4_define(DYNAMIC_ATTR, `FID_MEMBER(struct f_dynamic_attr, da, f1->da.ea_code != f2->da.ea_code,,)')
 254 m4_define(ACCESS_RTE, `FID_HIC(,[[do { if (!fs->rte) runtime("No route to access"); } while (0)]],NEVER_CONSTANT())')
 255
 256 #       2) Code wrapping
 257 #       The code produced in 1xx temporary diversions is a raw code without
 258 #       any auxiliary commands and syntactical structures around. When the
 259 #       instruction is done, INST_FLUSH is called. More precisely, it is called
 260 #       at the beginning of INST() call and at the end of file.
 261 #
 262 #       INST_FLUSH picks all the temporary diversions, wraps their content
 263 #       into appropriate headers and structures and saves them into global
 264 #       diversions listed:
 265 #
 266 #       4       enum fi_code
 267 #       5       enum fi_code to string
 268 #       6       dump line item
 269 #       7       dump line item callers
 270 #       8       linearize
 271 #       9       same (filter comparator)
 272 #       10      iterate
 273 #       1       union in struct f_inst
 274 #       3       constructors + interpreter
 275 #
 276 #       These global diversions contain blocks of code that can be directly
 277 #       put into the final file, yet it still can't be written out now as
 278 #       every instruction writes to all of these diversions.
 279
 280 #       Code wrapping diversion names. Here we want an explicit newline
 281 #       after the C comment.
 282 m4_define(FID_ZONE, `m4_divert($1) /* $2 for INST_NAME() */
 283 ')
 284 m4_define(FID_INST, `FID_ZONE(1, Instruction structure for config)')
 285 m4_define(FID_LINE, `FID_ZONE(2, Instruction structure for interpreter)')
 286 m4_define(FID_NEW, `FID_ZONE(3, Constructor)')
 287 m4_define(FID_ENUM, `FID_ZONE(4, Code enum)')
 288 m4_define(FID_ENUM_STR, `FID_ZONE(5, Code enum to string)')
 289 m4_define(FID_DUMP, `FID_ZONE(6, Dump line)')
 290 m4_define(FID_DUMP_CALLER, `FID_ZONE(7, Dump line caller)')
 291 m4_define(FID_LINEARIZE, `FID_ZONE(8, Linearize)')
 292 m4_define(FID_SAME, `FID_ZONE(9, Comparison)')
 293 m4_define(FID_ITERATE, `FID_ZONE(10, Iteration)')
 294
 295 #       This macro does all the code wrapping. See inline comments.
 296 m4_define(INST_FLUSH, `m4_ifdef([[INST_NAME]], [[
 297 FID_ENUM()m4_dnl                         Contents of enum fi_code { ... }
 298   INST_NAME(),
 299 FID_ENUM_STR()m4_dnl                     Contents of const char * indexed by enum fi_code
 300   [INST_NAME()] = "INST_NAME()",
 301 FID_INST()m4_dnl                         Anonymous structure inside struct f_inst
 302     struct {
 303 m4_undivert(101)m4_dnl
 304     } i_[[]]INST_NAME();
 305 FID_LINE()m4_dnl                         Anonymous structure inside struct f_line_item
 306     struct {
 307 m4_undivert(107)m4_dnl
 308     } i_[[]]INST_NAME();
 309 FID_NEW()m4_dnl                          Constructor and interpreter code together
 310 FID_HIC(
 311 [[m4_dnl                                 Public declaration of constructor in H file
 312 struct f_inst *f_new_inst_]]INST_NAME()[[(enum f_instruction_code fi_code
 313 m4_undivert(102)m4_dnl
 314 );]],
 315 [[m4_dnl                                 The one case in The Big Switch inside interpreter
 316   case INST_NAME():
 317   #define whati (&(what->i_]]INST_NAME()[[))
 318   m4_ifelse(m4_eval(INST_INVAL() > 0), 1, [[if (fstk->vcnt < INST_INVAL()) runtime("Stack underflow"); fstk->vcnt -= INST_INVAL(); ]])
 319   m4_undivert(108)m4_dnl
 320   #undef whati
 321   break;
 322 ]],
 323 [[m4_dnl                                 Constructor itself
 324 struct f_inst *f_new_inst_]]INST_NAME()[[(enum f_instruction_code fi_code
 325 m4_undivert(102)m4_dnl
 326 )
 327   {
 328     /* Allocate the structure */
 329     struct f_inst *what = fi_new(fi_code);
 330     FID_IFCONST([[uint constargs = 1;]])
 331
 332     /* Initialize all the members */
 333   #define whati (&(what->i_]]INST_NAME()[[))
 334   m4_undivert(103)m4_dnl
 335
 336     /* If not constant, return the instruction itself */
 337     FID_IFCONST([[if (!constargs)]])
 338       return what;
 339
 340     /* Try to pre-calculate the result */
 341     FID_IFCONST([[m4_undivert(108)]])m4_dnl
 342   #undef whati
 343   }
 344 ]])
 345
 346 FID_DUMP_CALLER()m4_dnl                  Case in another big switch used in instruction dumping (debug)
 347 case INST_NAME(): f_dump_line_item_]]INST_NAME()[[(item, indent + 1); break;
 348
 349 FID_DUMP()m4_dnl                         The dumper itself
 350 m4_ifdef([[FID_DUMP_BODY_EXISTS]],
 351 [[static inline void f_dump_line_item_]]INST_NAME()[[(const struct f_line_item *item_, const int indent)]],
 352 [[static inline void f_dump_line_item_]]INST_NAME()[[(const struct f_line_item *item UNUSED, const int indent UNUSED)]])
 353 m4_undefine([[FID_DUMP_BODY_EXISTS]])
 354 {
 355 #define item (&(item_->i_]]INST_NAME()[[))
 356 m4_undivert(104)m4_dnl
 357 #undef item
 358 }
 359
 360 FID_LINEARIZE()m4_dnl                    The linearizer
 361 case INST_NAME(): {
 362 #define whati (&(what->i_]]INST_NAME()[[))
 363 #define item (&(dest->items[pos].i_]]INST_NAME()[[))
 364   m4_undivert(105)m4_dnl
 365 #undef whati
 366 #undef item
 367   dest->items[pos].fi_code = what->fi_code;
 368   dest->items[pos].lineno = what->lineno;
 369   break;
 370 }
 371
 372 FID_SAME()m4_dnl                         This code compares two f_line"s while reconfiguring
 373 case INST_NAME():
 374 #define f1 (&(f1_->i_]]INST_NAME()[[))
 375 #define f2 (&(f2_->i_]]INST_NAME()[[))
 376 m4_undivert(106)m4_dnl
 377 #undef f1
 378 #undef f2
 379 break;
 380
 381 FID_ITERATE()m4_dnl                     The iterator
 382 case INST_NAME():
 383 #define whati (&(what->i_]]INST_NAME()[[))
 384 m4_undivert(109)m4_dnl
 385 #undef whati
 386 break;
 387
 388 m4_divert(-1)FID_FLUSH(101,200)m4_dnl  And finally this flushes all the unused diversions
 389 ]])')
 390
 391 m4_define(INST, `m4_dnl                         This macro is called on beginning of each instruction.
 392 INST_FLUSH()m4_dnl                              First, old data is flushed
 393 m4_define([[INST_NAME]], [[$1]])m4_dnl          Then we store instruction name,
 394 m4_define([[INST_INVAL]], [[$2]])m4_dnl         instruction input value count,
 395 m4_undefine([[INST_NEVER_CONSTANT]])m4_dnl      reset NEVER_CONSTANT trigger,
 396 m4_undefine([[INST_RESULT_TYPE]])m4_dnl         and reset RESULT_TYPE value.
 397 FID_INTERPRET_BODY()m4_dnl                      By default, every code is interpreter code.
 398 ')
 399
 400 #       3) Final preparation
 401 #
 402 #       Now we prepare all the code around the global diversions.
 403 #       It must be here, not in m4wrap, as we want M4 to mark the code
 404 #       by #line directives correctly, not to claim that every single line
 405 #       is at the beginning of the m4wrap directive.
 406 #
 407 #       This part is split by the final file.
 408 #       H for inst-gen.h
 409 #       I for inst-interpret.c
 410 #       C for inst-gen.c
 411 #
 412 #       So we in cycle:
 413 #         A. open a diversion
 414 #         B. send there some code
 415 #         C. close that diversion
 416 #         D. flush a global diversion
 417 #         E. open another diversion and goto B.
 418 #
 419 #       Final diversions
 420 #       200+    completed text before it is flushed to output
 421
 422 #       This is a list of output diversions
 423 m4_define(FID_WR_PUT_LIST)
 424
 425 #       This macro does the steps C to E, see before.
 426 m4_define(FID_WR_PUT_ALSO, `m4_define([[FID_WR_PUT_LIST]],FID_WR_PUT_LIST()[[FID_WR_DPUT(]]FID_WR_DIDX[[)FID_WR_DPUT(]]$1[[)]])m4_define([[FID_WR_DIDX]],m4_eval(FID_WR_DIDX+1))m4_divert(FID_WR_DIDX)')
 427
 428 #       These macros do the splitting between H/I/C
 429 m4_define(FID_WR_DIRECT, `m4_ifelse(TARGET,[[$1]],[[FID_WR_INIT()]],[[FID_WR_STOP()]])')
 430 m4_define(FID_WR_INIT, `m4_define([[FID_WR_DIDX]],200)m4_define([[FID_WR_PUT]],[[FID_WR_PUT_ALSO($]][[@)]])m4_divert(200)')
 431 m4_define(FID_WR_STOP, `m4_define([[FID_WR_PUT]])m4_divert(-1)')
 432
 433 #       Here is the direct code to be put into the output files
 434 #       together with the undiversions, being hidden under FID_WR_PUT()
 435
 436 m4_changequote([[,]])
 437 FID_WR_DIRECT(I)
 438 FID_WR_PUT(3)
 439 FID_WR_DIRECT(C)
 440
 441 #if defined(__GNUC__) && __GNUC__ >= 6
 442 #pragma GCC diagnostic push
 443 #pragma GCC diagnostic ignored "-Wmisleading-indentation"
 444 #endif
 445
 446 #include "nest/bird.h"
 447 #include "filter/filter.h"
 448 #include "filter/f-inst.h"
 449
 450 /* Instruction codes to string */
 451 static const char * const f_instruction_name_str[] = {
 452 FID_WR_PUT(5)
 453 };
 454
 455 const char *
 456 f_instruction_name_(enum f_instruction_code fi)
 457 {
 458   if (fi < (sizeof(f_instruction_name_str) / sizeof(f_instruction_name_str[0])))
 459     return f_instruction_name_str[fi];
 460   else
 461     bug("Got unknown instruction code: %d", fi);
 462 }
 463
 464 static inline struct f_inst *
 465 fi_new(enum f_instruction_code fi_code)
 466 {
 467   struct f_inst *what = cfg_allocz(sizeof(struct f_inst));
 468   what->lineno = ifs->lino;
 469   what->size = 1;
 470   what->fi_code = fi_code;
 471   return what;
 472 }
 473
 474 static inline struct f_inst *
 475 fi_constant(struct f_inst *what, struct f_val val)
 476 {
 477   what->fi_code = FI_CONSTANT;
 478   what->i_FI_CONSTANT.val = val;
 479   return what;
 480 }
 481
 482 static int
 483 f_const_promotion(struct f_inst *arg, enum f_type want)
 484 {
 485   if (arg->fi_code != FI_CONSTANT)
 486     return 0;
 487
 488   struct f_val *c = &arg->i_FI_CONSTANT.val;
 489
 490   if ((c->type == T_IP) && ipa_is_ip4(c->val.ip) && (want == T_QUAD)) {
 491     *c = (struct f_val) {
 492       .type = T_QUAD,
 493       .val.i = ipa_to_u32(c->val.ip),
 494     };
 495     return 1;
 496   }
 497
 498   return 0;
 499 }
 500
 501 #define v1 whati->f1->i_FI_CONSTANT.val
 502 #define v2 whati->f2->i_FI_CONSTANT.val
 503 #define v3 whati->f3->i_FI_CONSTANT.val
 504 #define vv(i) items[i]->i_FI_CONSTANT.val
 505 #define runtime(fmt, ...) cf_error("filter preevaluation, line %d: " fmt, ifs->lino, ##__VA_ARGS__)
 506 #define fpool cfg_mem
 507 #define falloc(size) cfg_alloc(size)
 508 /* Instruction constructors */
 509 FID_WR_PUT(3)
 510 #undef v1
 511 #undef v2
 512 #undef v3
 513 #undef vv
 514
 515 /* Line dumpers */
 516 #define INDENT (((const char *) f_dump_line_indent_str) + sizeof(f_dump_line_indent_str) - (indent) - 1)
 517 static const char f_dump_line_indent_str[] = "                                ";
 518
 519 FID_WR_PUT(6)
 520
 521 void f_dump_line(const struct f_line *dest, uint indent)
 522 {
 523   if (!dest) {
 524     debug("%sNo filter line (NULL)\n", INDENT);
 525     return;
 526   }
 527   debug("%sFilter line %p (len=%u)\n", INDENT, dest, dest->len);
 528   for (uint i=0; i<dest->len; i++) {
 529     const struct f_line_item *item = &dest->items[i];
 530     debug("%sInstruction %s at line %u\n", INDENT, f_instruction_name_(item->fi_code), item->lineno);
 531     switch (item->fi_code) {
 532 FID_WR_PUT(7)
 533       default: bug("Unknown instruction %x in f_dump_line", item->fi_code);
 534     }
 535   }
 536   debug("%sFilter line %p dump done\n", INDENT, dest);
 537 }
 538
 539 /* Linearize */
 540 static uint
 541 linearize(struct f_line *dest, const struct f_inst *what, uint pos)
 542 {
 543   for ( ; what; what = what->next) {
 544     switch (what->fi_code) {
 545 FID_WR_PUT(8)
 546     }
 547     pos++;
 548   }
 549   return pos;
 550 }
 551
 552 struct f_line *
 553 f_linearize_concat(const struct f_inst * const inst[], uint count)
 554 {
 555   uint len = 0;
 556   for (uint i=0; i<count; i++)
 557     for (const struct f_inst *what = inst[i]; what; what = what->next)
 558       len += what->size;
 559
 560   struct f_line *out = cfg_allocz(sizeof(struct f_line) + sizeof(struct f_line_item)*len);
 561
 562   for (uint i=0; i<count; i++)
 563     out->len = linearize(out, inst[i], out->len);
 564
 565 #ifdef LOCAL_DEBUG
 566   f_dump_line(out, 0);
 567 #endif
 568   return out;
 569 }
 570
 571 /* Filter line comparison */
 572 int
 573 f_same(const struct f_line *fl1, const struct f_line *fl2)
 574 {
 575   if ((!fl1) && (!fl2))
 576     return 1;
 577   if ((!fl1) || (!fl2))
 578     return 0;
 579   if (fl1->len != fl2->len)
 580     return 0;
 581   for (uint i=0; i<fl1->len; i++) {
 582 #define f1_ (&(fl1->items[i]))
 583 #define f2_ (&(fl2->items[i]))
 584     if (f1_->fi_code != f2_->fi_code)
 585       return 0;
 586     if (f1_->flags != f2_->flags)
 587       return 0;
 588
 589     switch(f1_->fi_code) {
 590 FID_WR_PUT(9)
 591     }
 592   }
 593 #undef f1_
 594 #undef f2_
 595   return 1;
 596 }
 597
 598
 599 /* Part of FI_SWITCH filter iterator */
 600 static void
 601 f_add_tree_lines(const struct f_tree *t, void *fit_)
 602 {
 603   struct filter_iterator * fit = fit_;
 604
 605   if (t->data)
 606     BUFFER_PUSH(fit->lines) = t->data;
 607 }
 608
 609 /* Filter line iterator */
 610 void
 611 f_add_lines(const struct f_line_item *what, struct filter_iterator *fit)
 612 {
 613   switch(what->fi_code) {
 614 FID_WR_PUT(10)
 615   }
 616 }
 617
 618
 619 #if defined(__GNUC__) && __GNUC__ >= 6
 620 #pragma GCC diagnostic pop
 621 #endif
 622
 623 FID_WR_DIRECT(H)
 624 /* Filter instruction codes */
 625 enum f_instruction_code {
 626 FID_WR_PUT(4)m4_dnl
 627 } PACKED;
 628
 629 /* Filter instruction structure for config */
 630 struct f_inst {
 631   struct f_inst *next;                  /* Next instruction */
 632   enum f_instruction_code fi_code;      /* Instruction code */
 633   enum f_type type;                     /* Type of returned value, if known */
 634   int size;                             /* How many instructions are underneath */
 635   int lineno;                           /* Line number */
 636   union {
 637 FID_WR_PUT(1)m4_dnl
 638   };
 639 };
 640
 641 /* Filter line item */
 642 struct f_line_item {
 643   enum f_instruction_code fi_code;      /* What to do */
 644   enum f_instruction_flags flags;       /* Flags, instruction-specific */
 645   uint lineno;                          /* Where */
 646   union {
 647 FID_WR_PUT(2)m4_dnl
 648   };
 649 };
 650
 651 /* Instruction constructors */
 652 FID_WR_PUT(3)
 653 m4_divert(-1)
 654
 655 #       4) Shipout
 656 #
 657 #       Everything is prepared in FID_WR_PUT_LIST now. Let's go!
 658
 659 m4_changequote(`,')
 660
 661 #       Flusher auxiliary macro
 662 m4_define(FID_FLUSH, `m4_ifelse($1,$2,,[[m4_undivert($1)FID_FLUSH(m4_eval($1+1),$2)]])')
 663
 664 #       Defining the macro used in FID_WR_PUT_LIST
 665 m4_define(FID_WR_DPUT, `m4_undivert($1)')
 666
 667 #       After the code is read and parsed, we:
 668 m4_m4wrap(`INST_FLUSH()m4_divert(0)FID_WR_PUT_LIST()m4_divert(-1)FID_FLUSH(1,200)')
 669
 670 m4_changequote([[,]])
 671 #       And now M4 is going to parse f-inst.c, fill the diversions
 672 #       and after the file is done, the content of m4_m4wrap (see before)
 673 #       is executed.