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1.1 root 1: /* Language-level data type conversion for GNU C++. 1.1.1.5 ! root 2: Copyright (C) 1987, 1988, 1992, 1993 Free Software Foundation, Inc. 1.1 root 3: Hacked by Michael Tiemann ([email protected]) 4: 5: This file is part of GNU CC. 6: 7: GNU CC is free software; you can redistribute it and/or modify 8: it under the terms of the GNU General Public License as published by 9: the Free Software Foundation; either version 2, or (at your option) 10: any later version. 11: 12: GNU CC is distributed in the hope that it will be useful, 13: but WITHOUT ANY WARRANTY; without even the implied warranty of 14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15: GNU General Public License for more details. 16: 17: You should have received a copy of the GNU General Public License 18: along with GNU CC; see the file COPYING. If not, write to 19: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ 20: 21: 22: /* This file contains the functions for converting C expressions 23: to different data types. The only entry point is `convert'. 24: Every language front end must have a `convert' function 25: but what kind of conversions it does will depend on the language. */ 26: 27: #include "config.h" 28: #include "tree.h" 1.1.1.4 root 29: #include "flags.h" 1.1 root 30: #include "cp-tree.h" 1.1.1.5 ! root 31: #include "convert.h" 1.1 root 32: 1.1.1.5 ! root 33: #undef NULL ! 34: #define NULL (char *)0 1.1 root 35: 36: /* Change of width--truncation and extension of integers or reals-- 37: is represented with NOP_EXPR. Proper functioning of many things 38: assumes that no other conversions can be NOP_EXPRs. 39: 40: Conversion between integer and pointer is represented with CONVERT_EXPR. 41: Converting integer to real uses FLOAT_EXPR 42: and real to integer uses FIX_TRUNC_EXPR. 43: 44: Here is a list of all the functions that assume that widening and 45: narrowing is always done with a NOP_EXPR: 46: In c-convert.c, convert_to_integer. 47: In c-typeck.c, build_binary_op_nodefault (boolean ops), 48: and truthvalue_conversion. 49: In expr.c: expand_expr, for operands of a MULT_EXPR. 50: In fold-const.c: fold. 51: In tree.c: get_narrower and get_unwidened. 52: 53: C++: in multiple-inheritance, converting between pointers may involve 54: adjusting them by a delta stored within the class definition. */ 55: 56: /* Subroutines of `convert'. */ 57: 58: static tree 1.1.1.5 ! root 59: cp_convert_to_pointer (type, expr) 1.1 root 60: tree type, expr; 61: { 62: register tree intype = TREE_TYPE (expr); 63: register enum tree_code form = TREE_CODE (intype); 64: 65: if (form == POINTER_TYPE) 66: { 67: intype = TYPE_MAIN_VARIANT (intype); 68: 69: if (TYPE_MAIN_VARIANT (type) != intype 1.1.1.2 root 70: && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE 71: && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) 1.1 root 72: { 73: enum tree_code code = PLUS_EXPR; 74: tree binfo = get_binfo (TREE_TYPE (type), TREE_TYPE (intype), 1); 75: if (binfo == error_mark_node) 76: return error_mark_node; 77: if (binfo == NULL_TREE) 78: { 79: binfo = get_binfo (TREE_TYPE (intype), TREE_TYPE (type), 1); 80: if (binfo == error_mark_node) 81: return error_mark_node; 82: code = MINUS_EXPR; 83: } 84: if (binfo) 85: { 86: if (TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (type)) 87: || TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (intype)) 88: || ! BINFO_OFFSET_ZEROP (binfo)) 89: { 90: /* Need to get the path we took. */ 91: tree path; 92: 93: if (code == PLUS_EXPR) 94: get_base_distance (TREE_TYPE (type), TREE_TYPE (intype), 0, &path); 95: else 96: get_base_distance (TREE_TYPE (intype), TREE_TYPE (type), 0, &path); 97: return build_vbase_path (code, type, expr, path, 0); 98: } 99: } 100: } 101: return build1 (NOP_EXPR, type, expr); 102: } 103: 1.1.1.4 root 104: my_friendly_assert (form != OFFSET_TYPE, 186); 1.1 root 105: 106: if (IS_AGGR_TYPE (intype)) 107: { 108: /* If we cannot convert to the specific pointer type, 109: try to convert to the type `void *'. */ 110: tree rval; 111: rval = build_type_conversion (CONVERT_EXPR, type, expr, 1); 112: if (rval) 113: { 114: if (rval == error_mark_node) 115: error ("ambiguous pointer conversion"); 116: return rval; 117: } 118: } 119: 1.1.1.5 ! root 120: return convert_to_pointer (type, expr); 1.1 root 121: } 122: 123: /* Like convert, except permit conversions to take place which 124: are not normally allowed due to visibility restrictions 125: (such as conversion from sub-type to private super-type). */ 126: static tree 127: convert_to_pointer_force (type, expr) 128: tree type, expr; 129: { 130: register tree intype = TREE_TYPE (expr); 131: register enum tree_code form = TREE_CODE (intype); 132: 133: if (integer_zerop (expr)) 134: { 135: if (type == TREE_TYPE (null_pointer_node)) 136: return null_pointer_node; 137: expr = build_int_2 (0, 0); 138: TREE_TYPE (expr) = type; 139: return expr; 140: } 141: 142: if (form == POINTER_TYPE) 143: { 144: intype = TYPE_MAIN_VARIANT (intype); 145: 146: if (TYPE_MAIN_VARIANT (type) != intype 1.1.1.2 root 147: && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE 148: && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) 1.1 root 149: { 150: enum tree_code code = PLUS_EXPR; 151: tree path; 152: int distance = get_base_distance (TREE_TYPE (type), 153: TREE_TYPE (intype), 0, &path); 154: if (distance == -2) 155: { 156: ambig: 157: error_with_aggr_type (TREE_TYPE (type), "type `%s' is ambiguous baseclass of `%s'", 158: TYPE_NAME_STRING (TREE_TYPE (intype))); 159: return error_mark_node; 160: } 161: if (distance == -1) 162: { 163: distance = get_base_distance (TREE_TYPE (intype), 164: TREE_TYPE (type), 0, &path); 165: if (distance == -2) 166: goto ambig; 167: if (distance < 0) 168: /* Doesn't need any special help from us. */ 169: return build1 (NOP_EXPR, type, expr); 170: 171: code = MINUS_EXPR; 172: } 173: return build_vbase_path (code, type, expr, path, 0); 174: } 175: return build1 (NOP_EXPR, type, expr); 176: } 177: 1.1.1.5 ! root 178: return cp_convert_to_pointer (type, expr); 1.1 root 179: } 180: 181: /* We are passing something to a function which requires a reference. 182: The type we are interested in is in TYPE. The initial 183: value we have to begin with is in ARG. 184: 1.1.1.4 root 185: FLAGS controls how we manage visibility checking. 186: CHECKCONST controls if we report error messages on const subversion. */ 1.1 root 187: static tree 1.1.1.4 root 188: build_up_reference (type, arg, flags, checkconst) 1.1 root 189: tree type, arg; 1.1.1.4 root 190: int flags, checkconst; 1.1 root 191: { 192: tree rval, targ; 193: int literal_flag = 0; 194: tree argtype = TREE_TYPE (arg), basetype = argtype; 195: tree target_type = TREE_TYPE (type); 196: tree binfo = NULL_TREE; 197: 1.1.1.4 root 198: my_friendly_assert (TREE_CODE (type) == REFERENCE_TYPE, 187); 1.1 root 199: if (flags != 0 200: && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) 201: && IS_AGGR_TYPE (argtype) 202: && IS_AGGR_TYPE (target_type)) 203: { 204: binfo = get_binfo (target_type, argtype, 205: (flags & LOOKUP_PROTECTED_OK) ? 3 : 2); 206: if ((flags & LOOKUP_PROTECT) && binfo == error_mark_node) 207: return error_mark_node; 208: if (basetype == NULL_TREE) 1.1.1.5 ! root 209: return (tree) error_not_base_type (target_type, argtype); 1.1 root 210: basetype = BINFO_TYPE (binfo); 211: } 212: 1.1.1.3 root 213: /* Pass along const and volatile down into the type. */ 214: if (TYPE_READONLY (type) || TYPE_VOLATILE (type)) 215: target_type = build_type_variant (target_type, TYPE_READONLY (type), 216: TYPE_VOLATILE (type)); 1.1 root 217: targ = arg; 218: if (TREE_CODE (targ) == SAVE_EXPR) 219: targ = TREE_OPERAND (targ, 0); 220: 221: switch (TREE_CODE (targ)) 222: { 223: case INDIRECT_REF: 224: /* This is a call to a constructor which did not know what it was 225: initializing until now: it needs to initialize a temporary. */ 226: if (TREE_HAS_CONSTRUCTOR (targ)) 227: { 228: tree temp = build_cplus_new (argtype, TREE_OPERAND (targ, 0), 1); 229: TREE_HAS_CONSTRUCTOR (targ) = 0; 1.1.1.4 root 230: return build_up_reference (type, temp, flags, 1); 1.1 root 231: } 232: /* Let &* cancel out to simplify resulting code. 233: Also, throw away intervening NOP_EXPRs. */ 234: arg = TREE_OPERAND (targ, 0); 235: if (TREE_CODE (arg) == NOP_EXPR || TREE_CODE (arg) == NON_LVALUE_EXPR 236: || (TREE_CODE (arg) == CONVERT_EXPR && TREE_REFERENCE_EXPR (arg))) 237: arg = TREE_OPERAND (arg, 0); 238: 1.1.1.3 root 239: /* in doing a &*, we have to get rid of the const'ness on the pointer 240: value. Haven't thought about volatile here. Pointers come to mind 241: here. */ 242: if (TREE_READONLY (arg)) 243: { 244: arg = copy_node (arg); 245: TREE_READONLY (arg) = 0; 246: } 247: 1.1 root 248: rval = build1 (CONVERT_EXPR, type, arg); 249: TREE_REFERENCE_EXPR (rval) = 1; 1.1.1.3 root 250: 251: /* propagate the const flag on something like: 252: 253: class Base { 254: public: 255: int foo; 256: }; 257: 258: class Derived : public Base { 259: public: 260: int bar; 261: }; 262: 263: void func(Base&); 264: 265: void func2(const Derived& d) { 266: func(d); 267: } 268: 269: on the d parameter. The below could have been avoided, if the flags 1.1.1.4 root 270: were down in the tree, not sure why they are not. (mrs) */ 1.1.1.3 root 271: /* The below code may have to be propagated to other parts of this 272: switch. */ 273: if (TREE_READONLY (targ) && !TREE_READONLY (arg) 274: && (TREE_CODE (arg) == PARM_DECL || TREE_CODE (arg) == VAR_DECL) 1.1.1.4 root 275: && TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE 276: && (TYPE_READONLY (target_type) && checkconst)) 1.1.1.3 root 277: { 1.1.1.4 root 278: arg = copy_node (arg); 1.1.1.3 root 279: TREE_READONLY (arg) = TREE_READONLY (targ); 280: } 1.1 root 281: literal_flag = TREE_CONSTANT (arg); 1.1.1.3 root 282: 283: goto done_but_maybe_warn; 1.1 root 284: 285: /* Get this out of a register if we happened to be in one by accident. 286: Also, build up references to non-lvalues it we must. */ 287: /* For &x[y], return (&) x+y */ 288: case ARRAY_REF: 289: if (mark_addressable (TREE_OPERAND (targ, 0)) == 0) 290: return error_mark_node; 291: rval = build_binary_op (PLUS_EXPR, TREE_OPERAND (targ, 0), 1.1.1.5 ! root 292: TREE_OPERAND (targ, 1), 1); 1.1 root 293: TREE_TYPE (rval) = type; 294: if (TREE_CONSTANT (TREE_OPERAND (targ, 1)) 295: && staticp (TREE_OPERAND (targ, 0))) 296: TREE_CONSTANT (rval) = 1; 297: goto done; 298: 299: case SCOPE_REF: 300: /* Could be a reference to a static member. */ 301: { 302: tree field = TREE_OPERAND (targ, 1); 303: if (TREE_STATIC (field)) 304: { 305: rval = build1 (ADDR_EXPR, type, field); 306: literal_flag = 1; 307: goto done; 308: } 309: } 1.1.1.5 ! root 310: ! 311: /* We should have farmed out member pointers above. */ ! 312: my_friendly_abort (188); 1.1 root 313: 314: case COMPONENT_REF: 315: rval = build_component_addr (targ, build_pointer_type (argtype), 316: "attempt to make a reference to bit-field structure member `%s'"); 317: TREE_TYPE (rval) = type; 318: literal_flag = staticp (TREE_OPERAND (targ, 0)); 1.1.1.3 root 319: 1.1 root 320: goto done_but_maybe_warn; 321: 322: /* Anything not already handled and not a true memory reference 323: needs to have a reference built up. Do so silently for 324: things like integers and return values from function, 325: but complain if we need a reference to something declared 326: as `register'. */ 327: 328: case RESULT_DECL: 329: if (staticp (targ)) 330: literal_flag = 1; 331: TREE_ADDRESSABLE (targ) = 1; 332: put_var_into_stack (targ); 333: break; 334: 335: case PARM_DECL: 336: if (targ == current_class_decl) 337: { 338: error ("address of `this' not available"); 1.1.1.4 root 339: #if 0 340: /* This code makes the following core dump the compiler on a sun4, 341: if the code below is used. 342: 343: class e_decl; 344: class a_decl; 345: typedef a_decl* a_ref; 346: 347: class a_s { 348: public: 349: a_s(); 350: void* append(a_ref& item); 351: }; 352: class a_decl { 353: public: 354: a_decl (e_decl *parent); 355: a_s generic_s; 356: a_s decls; 357: e_decl* parent; 358: }; 359: 360: class e_decl { 361: public: 362: e_decl(); 363: a_s implementations; 364: }; 365: 366: void foobar(void *); 367: 368: a_decl::a_decl(e_decl *parent) { 369: parent->implementations.append(this); 370: } 371: */ 372: 1.1 root 373: TREE_ADDRESSABLE (targ) = 1; /* so compiler doesn't die later */ 374: put_var_into_stack (targ); 1.1.1.5 ! root 375: break; 1.1.1.4 root 376: #else 377: return error_mark_node; 378: #endif 1.1 root 379: } 380: /* Fall through. */ 381: case VAR_DECL: 382: case CONST_DECL: 1.1.1.4 root 383: if (DECL_REGISTER (targ) && !TREE_ADDRESSABLE (targ)) 1.1 root 384: warning ("address needed to build reference for `%s', which is declared `register'", 385: IDENTIFIER_POINTER (DECL_NAME (targ))); 386: else if (staticp (targ)) 387: literal_flag = 1; 388: 389: TREE_ADDRESSABLE (targ) = 1; 390: put_var_into_stack (targ); 391: break; 392: 393: case COMPOUND_EXPR: 394: { 395: tree real_reference = build_up_reference (type, TREE_OPERAND (targ, 1), 1.1.1.4 root 396: LOOKUP_PROTECT, checkconst); 1.1 root 397: rval = build (COMPOUND_EXPR, type, TREE_OPERAND (targ, 0), real_reference); 398: TREE_CONSTANT (rval) = staticp (TREE_OPERAND (targ, 1)); 399: return rval; 400: } 401: 402: case MODIFY_EXPR: 403: case INIT_EXPR: 404: { 405: tree real_reference = build_up_reference (type, TREE_OPERAND (targ, 0), 1.1.1.4 root 406: LOOKUP_PROTECT, checkconst); 1.1 root 407: rval = build (COMPOUND_EXPR, type, arg, real_reference); 408: TREE_CONSTANT (rval) = staticp (TREE_OPERAND (targ, 0)); 409: return rval; 410: } 411: 412: case COND_EXPR: 413: return build (COND_EXPR, type, 414: TREE_OPERAND (targ, 0), 1.1.1.4 root 415: build_up_reference (type, TREE_OPERAND (targ, 1), 416: LOOKUP_PROTECT, checkconst), 417: build_up_reference (type, TREE_OPERAND (targ, 2), 418: LOOKUP_PROTECT, checkconst)); 1.1 root 419: 420: case WITH_CLEANUP_EXPR: 421: return build (WITH_CLEANUP_EXPR, type, 1.1.1.4 root 422: build_up_reference (type, TREE_OPERAND (targ, 0), 423: LOOKUP_PROTECT, checkconst), 1.1 root 424: 0, TREE_OPERAND (targ, 2)); 425: 426: case BIND_EXPR: 427: arg = TREE_OPERAND (targ, 1); 428: if (arg == NULL_TREE) 429: { 430: compiler_error ("({ ... }) expression not expanded when needed for reference"); 431: return error_mark_node; 432: } 433: rval = build1 (ADDR_EXPR, type, arg); 434: TREE_REFERENCE_EXPR (rval) = 1; 435: return rval; 436: 437: default: 438: break; 439: } 440: 441: if (TREE_ADDRESSABLE (targ) == 0) 442: { 443: tree temp; 444: 445: if (TREE_CODE (targ) == CALL_EXPR && IS_AGGR_TYPE (argtype)) 446: { 447: temp = build_cplus_new (argtype, targ, 1); 448: rval = build1 (ADDR_EXPR, type, temp); 449: goto done; 450: } 451: else 452: { 453: temp = get_temp_name (argtype, 0); 454: if (global_bindings_p ()) 455: { 456: /* Give this new temp some rtl and initialize it. */ 457: DECL_INITIAL (temp) = targ; 458: TREE_STATIC (temp) = 1; 459: finish_decl (temp, targ, NULL_TREE, 0); 460: /* Do this after declaring it static. */ 461: rval = build_unary_op (ADDR_EXPR, temp, 0); 462: literal_flag = TREE_CONSTANT (rval); 463: goto done; 464: } 465: else 466: { 467: rval = build_unary_op (ADDR_EXPR, temp, 0); 468: /* Put a value into the rtl. */ 469: if (IS_AGGR_TYPE (argtype)) 470: { 471: /* This may produce surprising results, 472: since we commit to initializing the temp 473: when the temp may not actually get used. */ 474: expand_aggr_init (temp, targ, 0); 475: TREE_TYPE (rval) = type; 476: literal_flag = TREE_CONSTANT (rval); 477: goto done; 478: } 479: else 480: { 481: if (binfo && !BINFO_OFFSET_ZEROP (binfo)) 482: rval = convert_pointer_to (target_type, rval); 483: else 484: TREE_TYPE (rval) = type; 485: return build (COMPOUND_EXPR, type, 486: build (MODIFY_EXPR, argtype, temp, arg), rval); 487: } 488: } 489: } 490: } 491: else 492: { 493: if (TREE_CODE (arg) == SAVE_EXPR) 1.1.1.3 root 494: my_friendly_abort (5); 1.1 root 495: rval = build1 (ADDR_EXPR, type, arg); 496: } 497: 498: done_but_maybe_warn: 1.1.1.4 root 499: if (checkconst && TREE_READONLY (arg) && ! TYPE_READONLY (target_type)) 1.1.1.5 ! root 500: readonly_error (arg, "conversion to reference", 1); 1.1 root 501: 502: done: 503: if (TYPE_USES_COMPLEX_INHERITANCE (argtype)) 504: { 505: TREE_TYPE (rval) = TYPE_POINTER_TO (argtype); 506: rval = convert_pointer_to (target_type, rval); 507: TREE_TYPE (rval) = type; 508: } 509: TREE_CONSTANT (rval) = literal_flag; 510: return rval; 511: } 512: 513: /* For C++: Only need to do one-level references, but cannot 514: get tripped up on signed/unsigned differences. 515: 516: If DECL is NULL_TREE it means convert as though casting (by force). 517: If it is ERROR_MARK_NODE, it means the conversion is implicit, 518: and that temporaries may be created. 1.1.1.4 root 519: Make sure the use of user-defined conversion operators is un-ambiguous. 520: Otherwise, DECL is a _DECL node which can be used in error reporting. 521: 522: FNDECL, PARMNUM, and ERRTYPE are only used when checking for use of 523: volatile or const references where they aren't desired. */ 1.1.1.5 ! root 524: 1.1 root 525: tree 1.1.1.4 root 526: convert_to_reference (decl, reftype, expr, fndecl, parmnum, 527: errtype, strict, flags) 1.1.1.5 ! root 528: 1.1 root 529: tree decl; 530: tree reftype, expr; 1.1.1.4 root 531: tree fndecl; 532: int parmnum; 533: char *errtype; 1.1 root 534: int strict, flags; 535: { 536: register tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); 537: register tree intype = TREE_TYPE (expr); 538: register enum tree_code form = TREE_CODE (intype); 1.1.1.4 root 539: tree rval = NULL_TREE; 1.1 root 540: 541: if (form == REFERENCE_TYPE) 542: intype = TREE_TYPE (intype); 543: intype = TYPE_MAIN_VARIANT (intype); 544: 545: /* @@ Probably need to have a check for X(X&) here. */ 546: 547: if (IS_AGGR_TYPE (intype)) 548: { 1.1.1.4 root 549: rval = build_type_conversion (CONVERT_EXPR, reftype, expr, 1); 1.1 root 550: if (rval) 551: { 552: if (rval == error_mark_node) 553: error ("ambiguous pointer conversion"); 554: return rval; 555: } 1.1.1.3 root 556: else if (type != intype 557: && (rval = build_type_conversion (CONVERT_EXPR, type, expr, 1))) 1.1 root 558: { 1.1.1.3 root 559: if (rval == error_mark_node) 560: return rval; 1.1 root 561: if (TYPE_NEEDS_DESTRUCTOR (type)) 562: { 1.1.1.5 ! root 563: rval = convert_to_reference (NULL_TREE, reftype, rval, NULL_TREE, ! 564: -1, (char *)NULL, strict, flags); 1.1 root 565: } 566: else 567: { 568: decl = get_temp_name (type, 0); 569: rval = build (INIT_EXPR, type, decl, rval); 570: rval = build (COMPOUND_EXPR, reftype, rval, 571: convert_to_reference (NULL_TREE, reftype, decl, 1.1.1.5 ! root 572: NULL_TREE, -1, (char*)NULL, 1.1 root 573: strict, flags)); 574: } 575: } 576: 577: if (form == REFERENCE_TYPE 578: && type != intype 579: && TYPE_USES_COMPLEX_INHERITANCE (intype)) 580: { 581: /* If it may move around, build a fresh reference. */ 582: expr = convert_from_reference (expr); 583: form = TREE_CODE (TREE_TYPE (expr)); 584: } 585: } 586: 587: /* @@ Perhaps this should try to go through a constructor first 588: @@ for proper initialization, but I am not sure when that 589: @@ is needed or desirable. 590: 591: @@ The second disjunct is provided to make references behave 1.1.1.5 ! root 592: @@ as some people think they should, i.e., an interconvertibility 1.1 root 593: @@ between references to builtin types (such as short and 594: @@ unsigned short). There should be no conversion between 595: @@ types whose codes are different, or whose sizes are different. */ 596: 597: if (((IS_AGGR_TYPE (type) || IS_AGGR_TYPE (intype)) 598: && comptypes (type, intype, strict)) 599: || (!IS_AGGR_TYPE (type) 600: && TREE_CODE (type) == TREE_CODE (intype) 601: && int_size_in_bytes (type) == int_size_in_bytes (intype))) 602: { 1.1.1.4 root 603: /* Section 13. */ 604: /* Since convert_for_initialization didn't call convert_for_assignment, 605: we have to do this checking here. XXX We should have a common 606: routine between here and convert_for_assignment. */ 607: if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE) 608: { 609: register tree ttl = TREE_TYPE (reftype); 610: register tree ttr = TREE_TYPE (TREE_TYPE (expr)); 611: 612: if (! TYPE_READONLY (ttl) && TYPE_READONLY (ttr)) 613: warn_for_assignment ("%s of non-`const &' reference from `const &'", 614: "reference to const given for argument %d of `%s'", 615: errtype, fndecl, parmnum, pedantic); 616: if (! TYPE_VOLATILE (ttl) && TYPE_VOLATILE (ttr)) 617: warn_for_assignment ("%s of non-`volatile &' reference from `volatile &'", 1.1.1.5 ! root 618: "reference to volatile given for argument %d of `%s'", 1.1.1.4 root 619: errtype, fndecl, parmnum, pedantic); 620: } 621: 1.1 root 622: /* If EXPR is of aggregate type, and is really a CALL_EXPR, 623: then we don't need to convert it to reference type if 624: it is only being used to initialize DECL which is also 625: of the same aggregate type. */ 626: if (form == REFERENCE_TYPE 627: || (decl != NULL_TREE && decl != error_mark_node 628: && IS_AGGR_TYPE (type) 629: && TREE_CODE (expr) == CALL_EXPR 630: && TYPE_MAIN_VARIANT (type) == intype)) 631: { 632: if (decl && decl != error_mark_node) 633: { 634: tree e1 = build (INIT_EXPR, void_type_node, decl, expr); 635: tree e2; 636: 637: TREE_SIDE_EFFECTS (e1) = 1; 638: if (form == REFERENCE_TYPE) 639: e2 = build1 (NOP_EXPR, reftype, decl); 640: else 641: { 642: e2 = build_unary_op (ADDR_EXPR, decl, 0); 643: TREE_TYPE (e2) = reftype; 644: TREE_REFERENCE_EXPR (e2) = 1; 645: } 646: return build_compound_expr (tree_cons (NULL_TREE, e1, 647: build_tree_list (NULL_TREE, e2))); 648: } 649: expr = copy_node (expr); 650: TREE_TYPE (expr) = reftype; 651: return expr; 652: } 653: if (decl == error_mark_node) 654: flags |= LOOKUP_PROTECTED_OK; 1.1.1.4 root 655: return build_up_reference (reftype, expr, flags, decl!=NULL_TREE); 1.1 root 656: } 657: 658: /* Definitely need to go through a constructor here. */ 659: if (TYPE_HAS_CONSTRUCTOR (type)) 660: { 1.1.1.4 root 661: tree init = build_method_call (NULL_TREE, constructor_name (type), 662: build_tree_list (NULL_TREE, expr), 663: TYPE_BINFO (type), LOOKUP_NO_CONVERSION); 664: 665: if (init != error_mark_node) 666: if (rval) 667: { 668: error ("both constructor and type conversion operator apply"); 669: return error_mark_node; 670: } 671: 672: init = build_method_call (NULL_TREE, constructor_name (type), 673: build_tree_list (NULL_TREE, expr), 1.1.1.5 ! root 674: TYPE_BINFO (type), LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); 1.1 root 675: 676: if (init == error_mark_node) 677: return error_mark_node; 678: rval = build_cplus_new (type, init, 1); 679: if (decl == error_mark_node) 680: flags |= LOOKUP_PROTECTED_OK; 1.1.1.4 root 681: return build_up_reference (reftype, rval, flags, decl!=NULL_TREE); 1.1 root 682: } 683: 1.1.1.4 root 684: my_friendly_assert (form != OFFSET_TYPE, 189); 685: 686: /* This is in two pieces for now, because pointer to first becomes 687: invalid once type_as_string is called again. */ 688: error ("cannot convert type `%s'", type_as_string (intype)); 689: error (" to type `%s'", type_as_string (reftype)); 1.1 root 690: 691: return error_mark_node; 692: } 693: 694: /* We are using a reference VAL for its value. Bash that reference all the 695: way down to its lowest form. */ 696: tree 697: convert_from_reference (val) 698: tree val; 699: { 700: tree type = TREE_TYPE (val); 701: 702: if (TREE_CODE (type) == OFFSET_TYPE) 703: type = TREE_TYPE (type); 704: if (TREE_CODE (type) == REFERENCE_TYPE) 705: { 706: tree target_type = TREE_TYPE (type); 1.1.1.5 ! root 707: tree nval; 1.1 root 708: 709: /* This can happen if we cast to a reference type. */ 710: if (TREE_CODE (val) == ADDR_EXPR) 711: { 1.1.1.5 ! root 712: nval = build1 (NOP_EXPR, build_pointer_type (target_type), val); ! 713: nval = build_indirect_ref (nval, 0); ! 714: /* The below was missing, are other important flags missing too? */ ! 715: TREE_SIDE_EFFECTS (nval) = TREE_SIDE_EFFECTS (val); ! 716: return nval; 1.1 root 717: } 718: 1.1.1.5 ! root 719: nval = build1 (INDIRECT_REF, TYPE_MAIN_VARIANT (target_type), val); ! 720: ! 721: TREE_THIS_VOLATILE (nval) = TYPE_VOLATILE (target_type); ! 722: TREE_SIDE_EFFECTS (nval) = TYPE_VOLATILE (target_type); ! 723: TREE_READONLY (nval) = TYPE_READONLY (target_type); ! 724: /* The below was missing, are other important flags missing too? */ ! 725: TREE_SIDE_EFFECTS (nval) = TREE_SIDE_EFFECTS (val); ! 726: return nval; 1.1 root 727: } 728: return val; 729: } 730: 731: /* See if there is a constructor of type TYPE which will convert 732: EXPR. The reference manual seems to suggest (8.5.6) that we need 733: not worry about finding constructors for base classes, then converting 734: to the derived class. 735: 736: MSGP is a pointer to a message that would be an appropriate error 737: string. If MSGP is NULL, then we are not interested in reporting 738: errors. */ 739: tree 740: convert_to_aggr (type, expr, msgp, protect) 741: tree type, expr; 742: char **msgp; 1.1.1.4 root 743: int protect; 1.1 root 744: { 745: tree basetype = type; 746: tree name = TYPE_IDENTIFIER (basetype); 747: tree function, fndecl, fntype, parmtypes, parmlist, result; 748: tree method_name; 749: enum visibility_type visibility; 750: int can_be_private, can_be_protected; 751: 752: if (! TYPE_HAS_CONSTRUCTOR (basetype)) 753: { 754: if (msgp) 755: *msgp = "type `%s' does not have a constructor"; 756: return error_mark_node; 757: } 758: 759: visibility = visibility_public; 760: can_be_private = 0; 761: can_be_protected = IDENTIFIER_CLASS_VALUE (name) || name == current_class_name; 762: 763: parmlist = build_tree_list (NULL_TREE, expr); 764: parmtypes = tree_cons (NULL_TREE, TREE_TYPE (expr), void_list_node); 765: 766: if (TYPE_USES_VIRTUAL_BASECLASSES (basetype)) 767: { 768: parmtypes = tree_cons (NULL_TREE, integer_type_node, parmtypes); 769: parmlist = tree_cons (NULL_TREE, integer_one_node, parmlist); 770: } 771: 772: /* The type of the first argument will be filled in inside the loop. */ 773: parmlist = tree_cons (NULL_TREE, integer_zero_node, parmlist); 774: parmtypes = tree_cons (NULL_TREE, TYPE_POINTER_TO (basetype), parmtypes); 775: 1.1.1.2 root 776: method_name = build_decl_overload (name, parmtypes, 1); 1.1 root 777: 778: /* constructors are up front. */ 779: fndecl = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (basetype), 0); 780: if (TYPE_HAS_DESTRUCTOR (basetype)) 781: fndecl = DECL_CHAIN (fndecl); 782: 783: while (fndecl) 784: { 785: if (DECL_ASSEMBLER_NAME (fndecl) == method_name) 786: { 787: function = fndecl; 788: if (protect) 789: { 790: if (TREE_PRIVATE (fndecl)) 791: { 792: can_be_private = 793: (basetype == current_class_type 794: || is_friend (basetype, current_function_decl) 795: || purpose_member (basetype, DECL_VISIBILITY (fndecl))); 796: if (! can_be_private) 797: goto found; 798: } 799: else if (TREE_PROTECTED (fndecl)) 800: { 801: if (! can_be_protected) 802: goto found; 803: } 804: } 805: goto found_and_ok; 806: } 807: fndecl = DECL_CHAIN (fndecl); 808: } 809: 810: /* No exact conversion was found. See if an approximate 811: one will do. */ 812: fndecl = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (basetype), 0); 813: if (TYPE_HAS_DESTRUCTOR (basetype)) 814: fndecl = DECL_CHAIN (fndecl); 815: 816: { 817: int saw_private = 0; 818: int saw_protected = 0; 819: struct candidate *candidates = 820: (struct candidate *) alloca ((decl_list_length (fndecl)+1) * sizeof (struct candidate)); 821: struct candidate *cp = candidates; 822: 823: while (fndecl) 824: { 825: function = fndecl; 826: cp->harshness = (unsigned short *)alloca (3 * sizeof (short)); 827: compute_conversion_costs (fndecl, parmlist, cp, 2); 828: if (cp->evil == 0) 829: { 830: cp->u.field = fndecl; 831: if (protect) 832: { 833: if (TREE_PRIVATE (fndecl)) 834: visibility = visibility_private; 835: else if (TREE_PROTECTED (fndecl)) 836: visibility = visibility_protected; 837: else 838: visibility = visibility_public; 839: } 840: else 841: visibility = visibility_public; 842: 843: if (visibility == visibility_private 844: ? (basetype == current_class_type 845: || is_friend (basetype, cp->function) 846: || purpose_member (basetype, DECL_VISIBILITY (fndecl))) 847: : visibility == visibility_protected 848: ? (can_be_protected 849: || purpose_member (basetype, DECL_VISIBILITY (fndecl))) 850: : 1) 851: { 852: if (cp->user == 0 && cp->b_or_d == 0 853: && cp->easy <= 1) 854: { 855: goto found_and_ok; 856: } 857: cp++; 858: } 859: else 860: { 861: if (visibility == visibility_private) 862: saw_private = 1; 863: else 864: saw_protected = 1; 865: } 866: } 867: fndecl = DECL_CHAIN (fndecl); 868: } 869: if (cp - candidates) 870: { 871: /* Rank from worst to best. Then cp will point to best one. 872: Private fields have their bits flipped. For unsigned 873: numbers, this should make them look very large. 874: If the best alternate has a (signed) negative value, 875: then all we ever saw were private members. */ 876: if (cp - candidates > 1) 877: qsort (candidates, /* char *base */ 878: cp - candidates, /* int nel */ 879: sizeof (struct candidate), /* int width */ 880: rank_for_overload); /* int (*compar)() */ 881: 882: --cp; 883: if (cp->evil > 1) 884: { 885: if (msgp) 886: *msgp = "ambiguous type conversion possible for `%s'"; 887: return error_mark_node; 888: } 889: 890: function = cp->function; 891: fndecl = cp->u.field; 892: goto found_and_ok; 893: } 894: else if (msgp) 895: { 896: if (saw_private) 897: if (saw_protected) 898: *msgp = "only private and protected conversions apply"; 899: else 900: *msgp = "only private conversions apply"; 901: else if (saw_protected) 902: *msgp = "only protected conversions apply"; 903: } 904: return error_mark_node; 905: } 906: /* NOTREACHED */ 907: 908: not_found: 909: if (msgp) *msgp = "no appropriate conversion to type `%s'"; 910: return error_mark_node; 911: found: 912: if (visibility == visibility_private) 913: if (! can_be_private) 914: { 915: if (msgp) 916: *msgp = TREE_PRIVATE (fndecl) 917: ? "conversion to type `%s' is private" 918: : "conversion to type `%s' is from private base class"; 919: return error_mark_node; 920: } 921: if (visibility == visibility_protected) 922: if (! can_be_protected) 923: { 924: if (msgp) 925: *msgp = TREE_PRIVATE (fndecl) 926: ? "conversion to type `%s' is protected" 927: : "conversion to type `%s' is from protected base class"; 928: return error_mark_node; 929: } 930: function = fndecl; 931: found_and_ok: 932: 933: /* It will convert, but we don't do anything about it yet. */ 934: if (msgp == 0) 935: return NULL_TREE; 936: 937: fntype = TREE_TYPE (function); 1.1.1.4 root 938: if (DECL_INLINE (function) && TREE_CODE (function) == FUNCTION_DECL) 1.1 root 939: function = build1 (ADDR_EXPR, build_pointer_type (fntype), function); 940: else 941: function = default_conversion (function); 942: 943: result = build_nt (CALL_EXPR, function, 944: convert_arguments (NULL_TREE, TYPE_ARG_TYPES (fntype), 945: parmlist, NULL_TREE, LOOKUP_NORMAL), 946: NULL_TREE); 947: TREE_TYPE (result) = TREE_TYPE (fntype); 948: TREE_SIDE_EFFECTS (result) = 1; 949: TREE_RAISES (result) = !! TYPE_RAISES_EXCEPTIONS (fntype); 950: return result; 951: } 952: 953: /* Call this when we know (for any reason) that expr is 954: not, in fact, zero. */ 955: tree 956: convert_pointer_to (binfo, expr) 957: tree binfo, expr; 958: { 959: register tree intype = TREE_TYPE (expr); 960: tree ptr_type; 961: tree type, rval; 962: 963: if (TREE_CODE (binfo) == TREE_VEC) 964: type = BINFO_TYPE (binfo); 965: else if (IS_AGGR_TYPE (binfo)) 966: { 967: type = binfo; 968: binfo = TYPE_BINFO (binfo); 969: } 970: else 971: { 972: type = binfo; 973: binfo = NULL_TREE; 974: } 975: 976: ptr_type = build_pointer_type (type); 977: if (ptr_type == TYPE_MAIN_VARIANT (intype)) 978: return expr; 979: 980: if (intype == error_mark_node) 981: return error_mark_node; 982: 1.1.1.4 root 983: my_friendly_assert (!integer_zerop (expr), 191); 1.1 root 984: 1.1.1.5 ! root 985: if (TREE_CODE (type) == RECORD_TYPE ! 986: && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE 1.1 root 987: && type != TYPE_MAIN_VARIANT (TREE_TYPE (intype))) 988: { 989: tree path; 1.1.1.5 ! root 990: int distance ! 991: = get_base_distance (type, TYPE_MAIN_VARIANT (TREE_TYPE (intype)), ! 992: 0, &path); 1.1 root 993: 1.1.1.3 root 994: /* This function shouldn't be called with unqualified arguments 995: but if it is, give them an error message that they can read. 996: */ 997: if (distance < 0) 998: { 999: error ("cannot convert a pointer of type `%s'", 1000: TYPE_NAME_STRING (TREE_TYPE (intype))); 1001: error_with_aggr_type (type, "to a pointer of type `%s'"); 1002: 1003: return error_mark_node; 1004: } 1.1 root 1005: 1006: return build_vbase_path (PLUS_EXPR, ptr_type, expr, path, 1); 1007: } 1008: rval = build1 (NOP_EXPR, ptr_type, 1009: TREE_CODE (expr) == NOP_EXPR ? TREE_OPERAND (expr, 0) : expr); 1010: TREE_CONSTANT (rval) = TREE_CONSTANT (expr); 1011: return rval; 1012: } 1013: 1014: /* Same as above, but don't abort if we get an "ambiguous" baseclass. 1015: There's only one virtual baseclass we are looking for, and once 1016: we find one such virtual baseclass, we have found them all. */ 1017: 1018: tree 1019: convert_pointer_to_vbase (binfo, expr) 1020: tree binfo; 1021: tree expr; 1022: { 1023: tree intype = TREE_TYPE (TREE_TYPE (expr)); 1024: tree binfos = TYPE_BINFO_BASETYPES (intype); 1025: int i; 1026: 1027: for (i = TREE_VEC_LENGTH (binfos)-1; i >= 0; i--) 1028: { 1029: tree basetype = BINFO_TYPE (TREE_VEC_ELT (binfos, i)); 1030: if (BINFO_TYPE (binfo) == basetype) 1031: return convert_pointer_to (binfo, expr); 1032: if (binfo_member (BINFO_TYPE (binfo), CLASSTYPE_VBASECLASSES (basetype))) 1033: return convert_pointer_to_vbase (binfo, convert_pointer_to (basetype, expr)); 1034: } 1.1.1.3 root 1035: my_friendly_abort (6); 1.1 root 1036: /* NOTREACHED */ 1037: return NULL_TREE; 1038: } 1039: 1040: /* Create an expression whose value is that of EXPR, 1041: converted to type TYPE. The TREE_TYPE of the value 1042: is always TYPE. This function implements all reasonable 1043: conversions; callers should filter out those that are 1044: not permitted by the language being compiled. */ 1045: 1046: tree 1047: convert (type, expr) 1048: tree type, expr; 1049: { 1050: register tree e = expr; 1051: register enum tree_code code = TREE_CODE (type); 1052: 1.1.1.4 root 1053: if (type == TREE_TYPE (expr) 1054: || TREE_CODE (expr) == ERROR_MARK) 1.1 root 1055: return expr; 1.1.1.4 root 1056: if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr))) 1057: return fold (build1 (NOP_EXPR, type, expr)); 1.1 root 1058: if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) 1059: return error_mark_node; 1060: if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE) 1061: { 1062: error ("void value not ignored as it ought to be"); 1063: return error_mark_node; 1064: } 1065: if (code == VOID_TYPE) 1066: { 1067: tree rval = build_type_conversion (NOP_EXPR, type, e, 0); 1068: /* If we can convert to void type via a type conversion, do so. */ 1069: if (rval) 1070: return rval; 1071: return build1 (CONVERT_EXPR, type, e); 1072: } 1073: #if 0 1074: /* This is incorrect. A truncation can't be stripped this way. 1075: Extensions will be stripped by the use of get_unwidened. */ 1076: if (TREE_CODE (expr) == NOP_EXPR) 1077: return convert (type, TREE_OPERAND (expr, 0)); 1078: #endif 1079: 1080: /* Just convert to the type of the member. */ 1081: if (code == OFFSET_TYPE) 1082: { 1083: type = TREE_TYPE (type); 1084: code = TREE_CODE (type); 1085: } 1086: 1087: /* C++ */ 1088: if (code == REFERENCE_TYPE) 1.1.1.4 root 1089: return fold (convert_to_reference (error_mark_node, 1090: type, e, 1091: NULL_TREE, -1, (char *)NULL, 1092: -1, LOOKUP_NORMAL)); 1.1 root 1093: else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) 1094: e = convert_from_reference (e); 1095: 1096: if (code == INTEGER_TYPE || code == ENUMERAL_TYPE) 1.1.1.5 ! root 1097: { ! 1098: tree intype = TREE_TYPE (expr); ! 1099: enum tree_code form = TREE_CODE (intype); ! 1100: if (flag_int_enum_equivalence == 0 ! 1101: && TREE_CODE (type) == ENUMERAL_TYPE ! 1102: && form == INTEGER_TYPE) ! 1103: { ! 1104: if (pedantic) ! 1105: pedwarn ("anachronistic conversion from integer type to enumeral type `%s'", ! 1106: TYPE_NAME_STRING (type)); ! 1107: if (flag_pedantic_errors) ! 1108: return error_mark_node; ! 1109: } ! 1110: if (form == OFFSET_TYPE) ! 1111: error_with_decl (TYPE_NAME (TYPE_OFFSET_BASETYPE (intype)), ! 1112: "pointer-to-member expression object not composed with type `%s' object"); ! 1113: else if (IS_AGGR_TYPE (intype)) ! 1114: { ! 1115: tree rval; ! 1116: rval = build_type_conversion (CONVERT_EXPR, type, expr, 1); ! 1117: if (rval) return rval; ! 1118: error ("aggregate value used where an integer was expected"); ! 1119: return error_mark_node; ! 1120: } ! 1121: return fold (convert_to_integer (type, e)); ! 1122: } 1.1 root 1123: if (code == POINTER_TYPE) 1.1.1.5 ! root 1124: return fold (cp_convert_to_pointer (type, e)); 1.1 root 1125: if (code == REAL_TYPE) 1.1.1.5 ! root 1126: { ! 1127: if (IS_AGGR_TYPE (TREE_TYPE (e))) ! 1128: { ! 1129: tree rval; ! 1130: rval = build_type_conversion (CONVERT_EXPR, type, e, 1); ! 1131: if (rval) ! 1132: return rval; ! 1133: else ! 1134: error ("aggregate value used where a floating point value was expected"); ! 1135: } ! 1136: return fold (convert_to_real (type, e)); ! 1137: } 1.1 root 1138: 1139: /* New C++ semantics: since assignment is now based on 1140: memberwise copying, if the rhs type is derived from the 1141: lhs type, then we may still do a conversion. */ 1142: if (IS_AGGR_TYPE_CODE (code)) 1143: { 1144: tree dtype = TREE_TYPE (e); 1145: 1146: if (TREE_CODE (dtype) == REFERENCE_TYPE) 1147: { 1148: e = convert_from_reference (e); 1149: dtype = TREE_TYPE (e); 1150: } 1151: dtype = TYPE_MAIN_VARIANT (dtype); 1152: 1153: /* Conversion between aggregate types. New C++ semantics allow 1154: objects of derived type to be cast to objects of base type. 1.1.1.2 root 1155: Old semantics only allowed this between pointers. 1.1 root 1156: 1157: There may be some ambiguity between using a constructor 1158: vs. using a type conversion operator when both apply. */ 1159: 1160: if (IS_AGGR_TYPE (dtype)) 1161: { 1162: tree binfo; 1163: 1164: tree conversion = TYPE_HAS_CONVERSION (dtype) 1165: ? build_type_conversion (CONVERT_EXPR, type, e, 1) : NULL_TREE; 1166: 1167: if (TYPE_HAS_CONSTRUCTOR (type)) 1168: { 1.1.1.4 root 1169: tree rval = build_method_call (NULL_TREE, constructor_name (type), 1170: build_tree_list (NULL_TREE, e), 1171: TYPE_BINFO (type), 1.1 root 1172: conversion ? LOOKUP_NO_CONVERSION : 0); 1173: 1174: if (rval != error_mark_node) 1175: { 1176: if (conversion) 1177: { 1178: error ("both constructor and type conversion operator apply"); 1179: return error_mark_node; 1180: } 1181: /* call to constructor successful. */ 1182: rval = build_cplus_new (type, rval, 0); 1183: return rval; 1184: } 1185: } 1186: /* Type conversion successful/applies. */ 1187: if (conversion) 1188: { 1189: if (conversion == error_mark_node) 1190: error ("ambiguous pointer conversion"); 1191: return conversion; 1192: } 1193: 1194: /* now try normal C++ assignment semantics. */ 1195: binfo = TYPE_BINFO (dtype); 1196: if (BINFO_TYPE (binfo) == type 1197: || (binfo = get_binfo (type, dtype, 1))) 1198: { 1199: if (binfo == error_mark_node) 1200: return error_mark_node; 1201: } 1202: if (binfo != NULL_TREE) 1203: { 1204: if (lvalue_p (e)) 1205: { 1206: e = build_unary_op (ADDR_EXPR, e, 0); 1207: 1208: if (! BINFO_OFFSET_ZEROP (binfo)) 1209: e = build (PLUS_EXPR, TYPE_POINTER_TO (type), 1210: e, BINFO_OFFSET (binfo)); 1211: return build1 (INDIRECT_REF, type, e); 1212: } 1213: 1214: sorry ("addressable aggregates"); 1215: return error_mark_node; 1216: } 1217: error ("conversion between incompatible aggregate types requested"); 1218: return error_mark_node; 1219: } 1220: /* conversion from non-aggregate to aggregate type requires constructor. */ 1221: else if (TYPE_HAS_CONSTRUCTOR (type)) 1222: { 1223: tree rval; 1.1.1.4 root 1224: tree init = build_method_call (NULL_TREE, constructor_name (type), 1225: build_tree_list (NULL_TREE, e), 1226: TYPE_BINFO (type), LOOKUP_NORMAL); 1.1 root 1227: if (init == error_mark_node) 1228: { 1229: error_with_aggr_type (type, "in conversion to type `%s'"); 1230: return error_mark_node; 1231: } 1232: rval = build_cplus_new (type, init, 0); 1233: return rval; 1234: } 1235: } 1236: 1237: /* If TYPE or TREE_TYPE (EXPR) is not on the permanent_obstack, 1238: then the it won't be hashed and hence compare as not equal, 1239: even when it is. */ 1240: if (code == ARRAY_TYPE 1241: && TREE_TYPE (TREE_TYPE (expr)) == TREE_TYPE (type) 1242: && index_type_equal (TYPE_DOMAIN (TREE_TYPE (expr)), TYPE_DOMAIN (type))) 1243: return expr; 1244: 1245: error ("conversion to non-scalar type requested"); 1246: return error_mark_node; 1247: } 1248: 1249: /* Like convert, except permit conversions to take place which 1250: are not normally allowed due to visibility restrictions 1251: (such as conversion from sub-type to private super-type). */ 1252: tree 1253: convert_force (type, expr) 1254: tree type; 1255: tree expr; 1256: { 1257: register tree e = expr; 1258: register enum tree_code code = TREE_CODE (type); 1259: 1260: if (code == REFERENCE_TYPE) 1.1.1.4 root 1261: return fold (convert_to_reference (0, type, e, 1262: NULL_TREE, -1, (char *)NULL, 1263: -1, 0)); 1.1 root 1264: else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) 1265: e = convert_from_reference (e); 1266: 1267: if (code == POINTER_TYPE) 1268: return fold (convert_to_pointer_force (type, e)); 1269: 1270: { 1271: int old_equiv = flag_int_enum_equivalence; 1272: flag_int_enum_equivalence = 1; 1273: e = convert (type, e); 1274: flag_int_enum_equivalence = old_equiv; 1275: } 1276: return e; 1277: } 1278: 1279: /* Subroutine of build_type_conversion. */ 1280: static tree 1281: build_type_conversion_1 (xtype, basetype, expr, typename, for_sure) 1282: tree xtype, basetype; 1283: tree expr; 1284: tree typename; 1285: int for_sure; 1286: { 1287: tree first_arg = expr; 1288: tree rval; 1289: int flags; 1290: 1291: if (for_sure == 0) 1292: { 1293: if (! lvalue_p (expr)) 1294: first_arg = build1 (NOP_EXPR, TYPE_POINTER_TO (basetype), integer_zero_node); 1295: flags = LOOKUP_PROTECT; 1296: } 1297: else 1298: flags = LOOKUP_NORMAL; 1299: 1.1.1.4 root 1300: rval = build_method_call (first_arg, constructor_name (typename), 1301: NULL_TREE, NULL_TREE, flags); 1.1 root 1302: if (rval == error_mark_node) 1303: { 1304: if (for_sure == 0) 1305: return NULL_TREE; 1306: return error_mark_node; 1307: } 1308: if (first_arg != expr) 1309: { 1310: expr = build_up_reference (build_reference_type (TREE_TYPE (expr)), expr, 1.1.1.4 root 1311: LOOKUP_COMPLAIN, 1); 1.1 root 1312: TREE_VALUE (TREE_OPERAND (rval, 1)) = build_unary_op (ADDR_EXPR, expr, 0); 1313: } 1314: if (TREE_CODE (TREE_TYPE (rval)) == REFERENCE_TYPE 1315: && TREE_CODE (xtype) != REFERENCE_TYPE) 1316: rval = default_conversion (rval); 1317: 1318: if (pedantic 1319: && TREE_TYPE (xtype) 1320: && (TREE_READONLY (TREE_TYPE (TREE_TYPE (rval))) 1321: > TREE_READONLY (TREE_TYPE (xtype)))) 1322: pedwarn ("user-defined conversion casting away `const'"); 1323: return convert (xtype, rval); 1324: } 1325: 1326: /* Convert an aggregate EXPR to type XTYPE. If a conversion 1327: exists, return the attempted conversion. This may 1328: return ERROR_MARK_NODE if the conversion is not 1329: allowed (references private members, etc). 1330: If no conversion exists, NULL_TREE is returned. 1331: 1332: If (FOR_SURE & 1) is non-zero, then we allow this type conversion 1333: to take place immediately. Otherwise, we build a SAVE_EXPR 1334: which can be evaluated if the results are ever needed. 1335: 1336: If FOR_SURE >= 2, then we only look for exact conversions. 1337: 1338: TYPE may be a reference type, in which case we first look 1339: for something that will convert to a reference type. If 1340: that fails, we will try to look for something of the 1341: reference's target type, and then return a reference to that. */ 1342: tree 1343: build_type_conversion (code, xtype, expr, for_sure) 1344: enum tree_code code; 1345: tree xtype, expr; 1346: int for_sure; 1347: { 1348: /* C++: check to see if we can convert this aggregate type 1349: into the required scalar type. */ 1350: tree type, type_default; 1351: tree typename = build_typename_overload (xtype), *typenames; 1352: int n_variants = 0; 1353: tree basetype, save_basetype; 1354: tree rval; 1355: int exact_conversion = for_sure >= 2; 1356: for_sure &= 1; 1357: 1358: if (expr == error_mark_node) 1359: return error_mark_node; 1360: 1361: basetype = TREE_TYPE (expr); 1362: if (TREE_CODE (basetype) == REFERENCE_TYPE) 1363: basetype = TREE_TYPE (basetype); 1364: 1365: basetype = TYPE_MAIN_VARIANT (basetype); 1366: if (! TYPE_LANG_SPECIFIC (basetype) || ! TYPE_HAS_CONVERSION (basetype)) 1367: return 0; 1368: 1369: if (TREE_CODE (xtype) == POINTER_TYPE 1370: || TREE_CODE (xtype) == REFERENCE_TYPE) 1371: { 1372: /* Prepare to match a variant of this type. */ 1373: type = TYPE_MAIN_VARIANT (TREE_TYPE (xtype)); 1374: for (n_variants = 0; type; type = TYPE_NEXT_VARIANT (type)) 1375: n_variants++; 1376: typenames = (tree *)alloca (n_variants * sizeof (tree)); 1377: for (n_variants = 0, type = TYPE_MAIN_VARIANT (TREE_TYPE (xtype)); 1378: type; n_variants++, type = TYPE_NEXT_VARIANT (type)) 1379: { 1380: if (type == TREE_TYPE (xtype)) 1381: typenames[n_variants] = typename; 1382: else if (TREE_CODE (xtype) == POINTER_TYPE) 1383: typenames[n_variants] = build_typename_overload (build_pointer_type (type)); 1384: else 1385: typenames[n_variants] = build_typename_overload (build_reference_type (type)); 1386: } 1387: } 1388: 1389: save_basetype = basetype; 1390: type = xtype; 1391: 1392: while (TYPE_HAS_CONVERSION (basetype)) 1393: { 1394: int i; 1395: if (lookup_fnfields (TYPE_BINFO (basetype), typename, 0)) 1396: return build_type_conversion_1 (xtype, basetype, expr, typename, for_sure); 1397: for (i = 0; i < n_variants; i++) 1398: if (typenames[i] != typename 1399: && lookup_fnfields (TYPE_BINFO (basetype), typenames[i], 0)) 1400: return build_type_conversion_1 (xtype, basetype, expr, typenames[i], for_sure); 1401: 1402: if (TYPE_BINFO_BASETYPES (basetype)) 1403: basetype = TYPE_BINFO_BASETYPE (basetype, 0); 1404: else break; 1405: } 1406: 1407: if (TREE_CODE (type) == REFERENCE_TYPE) 1408: { 1409: tree first_arg = expr; 1410: type = TYPE_MAIN_VARIANT (TREE_TYPE (type)); 1411: basetype = save_basetype; 1412: 1413: /* May need to build a temporary for this. */ 1414: while (TYPE_HAS_CONVERSION (basetype)) 1415: { 1416: if (lookup_fnfields (TYPE_BINFO (basetype), typename, 0)) 1417: { 1418: int flags; 1419: 1420: if (for_sure == 0) 1421: { 1422: if (! lvalue_p (expr)) 1423: first_arg = build1 (NOP_EXPR, TYPE_POINTER_TO (basetype), integer_zero_node); 1424: flags = LOOKUP_PROTECT; 1425: } 1426: else 1427: flags = LOOKUP_NORMAL; 1.1.1.4 root 1428: rval = build_method_call (first_arg, constructor_name (typename), 1429: NULL_TREE, NULL_TREE, flags); 1.1 root 1430: if (rval == error_mark_node) 1431: { 1432: if (for_sure == 0) 1433: return NULL_TREE; 1434: return error_mark_node; 1435: } 1436: TREE_VALUE (TREE_OPERAND (rval, 1)) = expr; 1437: 1438: if (IS_AGGR_TYPE (type)) 1439: { 1.1.1.4 root 1440: tree init = build_method_call (NULL_TREE, 1441: constructor_name (type), 1442: build_tree_list (NULL_TREE, rval), NULL_TREE, LOOKUP_NORMAL); 1.1 root 1443: tree temp = build_cplus_new (type, init, 1); 1444: return build_up_reference (TYPE_REFERENCE_TO (type), temp, 1.1.1.4 root 1445: LOOKUP_COMPLAIN, 1); 1.1 root 1446: } 1447: return convert (xtype, rval); 1448: } 1449: if (TYPE_BINFO_BASETYPES (basetype)) 1450: basetype = TYPE_BINFO_BASETYPE (basetype, 0); 1451: else break; 1452: } 1453: /* No free conversions for reference types, right?. */ 1454: return NULL_TREE; 1455: } 1456: 1457: if (exact_conversion) 1458: return NULL_TREE; 1459: 1460: /* No perfect match found, try default. */ 1461: if (code == CONVERT_EXPR && TREE_CODE (type) == POINTER_TYPE) 1462: type_default = ptr_type_node; 1463: else if (type == void_type_node) 1464: return NULL_TREE; 1465: else 1466: { 1467: tree tmp = default_conversion (build1 (NOP_EXPR, type, integer_zero_node)); 1468: if (tmp == error_mark_node) 1469: return NULL_TREE; 1470: type_default = TREE_TYPE (tmp); 1471: } 1472: 1473: basetype = save_basetype; 1474: 1475: if (type_default != type) 1476: { 1477: type = type_default; 1478: typename = build_typename_overload (type); 1479: 1480: while (TYPE_HAS_CONVERSION (basetype)) 1481: { 1482: if (lookup_fnfields (TYPE_BINFO (basetype), typename, 0)) 1483: return build_type_conversion_1 (xtype, basetype, expr, typename, for_sure); 1484: if (TYPE_BINFO_BASETYPES (basetype)) 1485: basetype = TYPE_BINFO_BASETYPE (basetype, 0); 1486: else break; 1487: } 1488: } 1489: 1490: try_pointer: 1491: 1492: if (type == ptr_type_node) 1493: { 1494: /* Try converting to some other pointer type 1495: with which void* is compatible, or in situations 1496: in which void* is appropriate (such as &&,||, and !). */ 1497: 1498: while (TYPE_HAS_CONVERSION (basetype)) 1499: { 1500: if (CLASSTYPE_CONVERSION (basetype, ptr_conv) != 0) 1501: { 1502: if (CLASSTYPE_CONVERSION (basetype, ptr_conv) == error_mark_node) 1503: return error_mark_node; 1504: typename = DECL_NAME (CLASSTYPE_CONVERSION (basetype, ptr_conv)); 1505: return build_type_conversion_1 (xtype, basetype, expr, typename, for_sure); 1506: } 1507: if (TYPE_BINFO_BASETYPES (basetype)) 1508: basetype = TYPE_BINFO_BASETYPE (basetype, 0); 1509: else break; 1510: } 1511: } 1512: if (TREE_CODE (type) == POINTER_TYPE 1513: && TYPE_READONLY (TREE_TYPE (type)) 1514: && TYPE_MAIN_VARIANT (TREE_TYPE (type)) == void_type_node) 1515: { 1516: /* Try converting to some other pointer type 1517: with which const void* is compatible. */ 1518: 1519: while (TYPE_HAS_CONVERSION (basetype)) 1520: { 1521: if (CLASSTYPE_CONVERSION (basetype, constptr_conv) != 0) 1522: { 1523: if (CLASSTYPE_CONVERSION (basetype, constptr_conv) == error_mark_node) 1524: return error_mark_node; 1525: typename = DECL_NAME (CLASSTYPE_CONVERSION (basetype, constptr_conv)); 1526: return build_type_conversion_1 (xtype, basetype, expr, typename, for_sure); 1527: } 1528: if (TYPE_BINFO_BASETYPES (basetype)) 1529: basetype = TYPE_BINFO_BASETYPE (basetype, 0); 1530: else break; 1531: } 1532: } 1533: /* Use the longer or shorter conversion that is appropriate. Have 1534: to check against 0 because the conversion may come from a baseclass. */ 1535: if (TREE_CODE (type) == INTEGER_TYPE 1536: && TYPE_HAS_INT_CONVERSION (basetype) 1537: && CLASSTYPE_CONVERSION (basetype, int_conv) != 0 1538: && CLASSTYPE_CONVERSION (basetype, int_conv) != error_mark_node) 1539: { 1540: typename = DECL_NAME (CLASSTYPE_CONVERSION (basetype, int_conv)); 1541: return build_type_conversion_1 (xtype, basetype, expr, typename, for_sure); 1542: } 1543: if (TREE_CODE (type) == REAL_TYPE 1544: && TYPE_HAS_REAL_CONVERSION (basetype) 1545: && CLASSTYPE_CONVERSION (basetype, real_conv) != 0 1546: && CLASSTYPE_CONVERSION (basetype, real_conv) != error_mark_node) 1547: { 1548: typename = DECL_NAME (CLASSTYPE_CONVERSION (basetype, real_conv)); 1549: return build_type_conversion_1 (xtype, basetype, expr, typename, for_sure); 1550: } 1551: 1552: /* THIS IS A KLUDGE. */ 1553: if (TREE_CODE (type) != POINTER_TYPE 1554: && (code == TRUTH_ANDIF_EXPR 1555: || code == TRUTH_ORIF_EXPR 1556: || code == TRUTH_NOT_EXPR)) 1557: { 1558: /* Here's when we can convert to a pointer. */ 1559: type = ptr_type_node; 1560: goto try_pointer; 1561: } 1562: 1563: /* THESE ARE TOTAL KLUDGES. */ 1564: /* Default promotion yields no new alternatives, try 1565: conversions which are anti-default, such as 1566: 1567: double -> float or int -> unsigned or unsigned -> long 1568: 1569: */ 1.1.1.3 root 1570: if (type_default == type 1571: && (TREE_CODE (type) == INTEGER_TYPE || TREE_CODE (type) == REAL_TYPE)) 1.1 root 1572: { 1573: int not_again = 0; 1574: 1575: if (type == double_type_node) 1576: typename = build_typename_overload (float_type_node); 1577: else if (type == integer_type_node) 1578: typename = build_typename_overload (unsigned_type_node); 1579: else if (type == unsigned_type_node) 1580: typename = build_typename_overload (long_integer_type_node); 1581: 1582: again: 1583: basetype = save_basetype; 1584: while (TYPE_HAS_CONVERSION (basetype)) 1585: { 1586: if (lookup_fnfields (TYPE_BINFO (basetype), typename, 0)) 1587: return build_type_conversion_1 (xtype, basetype, expr, typename, for_sure); 1588: if (TYPE_BINFO_BASETYPES (basetype)) 1589: basetype = TYPE_BINFO_BASETYPE (basetype, 0); 1590: else break; 1591: } 1.1.1.2 root 1592: if (! not_again) 1.1 root 1593: { 1.1.1.2 root 1594: if (type == integer_type_node) 1595: { 1596: typename = build_typename_overload (long_integer_type_node); 1597: not_again = 1; 1598: goto again; 1599: } 1600: else 1601: { 1602: typename = build_typename_overload (integer_type_node); 1603: not_again = 1; 1604: goto again; 1605: } 1.1 root 1606: } 1607: } 1608: 1609: /* Now, try C promotions... 1610: 1611: float -> int 1612: int -> float, void * 1613: void * -> int 1614: 1615: Truthvalue conversions let us try to convert 1616: to pointer if we were going for int, and to int 1617: if we were looking for pointer. */ 1618: 1619: basetype = save_basetype; 1620: if (TREE_CODE (type) == REAL_TYPE 1621: || (TREE_CODE (type) == POINTER_TYPE 1622: && (code == TRUTH_ANDIF_EXPR 1623: || code == TRUTH_ORIF_EXPR 1624: || code == TRUTH_NOT_EXPR))) 1625: type = integer_type_node; 1626: else if (TREE_CODE (type) == INTEGER_TYPE) 1627: if (TYPE_HAS_REAL_CONVERSION (basetype)) 1628: type = double_type_node; 1629: else 1630: return NULL_TREE; 1631: else 1632: return NULL_TREE; 1633: 1634: typename = build_typename_overload (type); 1635: while (TYPE_HAS_CONVERSION (basetype)) 1636: { 1637: if (lookup_fnfields (TYPE_BINFO (basetype), typename, 0)) 1638: { 1639: rval = build_type_conversion_1 (xtype, basetype, expr, typename, for_sure); 1640: return rval; 1641: } 1642: if (TYPE_BINFO_BASETYPES (basetype)) 1643: basetype = TYPE_BINFO_BASETYPE (basetype, 0); 1644: else 1645: break; 1646: } 1647: 1648: return NULL_TREE; 1649: } 1650: 1651: /* Must convert two aggregate types to non-aggregate type. 1652: Attempts to find a non-ambiguous, "best" type conversion. 1653: 1654: Return 1 on success, 0 on failure. 1655: 1656: @@ What are the real semantics of this supposed to be??? */ 1657: int 1658: build_default_binary_type_conversion (code, arg1, arg2) 1659: enum tree_code code; 1660: tree *arg1, *arg2; 1661: { 1662: tree type1 = TREE_TYPE (*arg1); 1663: tree type2 = TREE_TYPE (*arg2); 1664: char *name1, *name2; 1665: 1666: if (TREE_CODE (type1) == REFERENCE_TYPE) 1667: type1 = TREE_TYPE (type1); 1668: if (TREE_CODE (type2) == REFERENCE_TYPE) 1669: type2 = TREE_TYPE (type2); 1670: 1671: if (TREE_CODE (TYPE_NAME (type1)) != TYPE_DECL) 1672: { 1673: tree decl = typedecl_for_tag (type1); 1674: if (decl) 1.1.1.2 root 1675: error ("type conversion nonexistent for type `%s'", 1.1 root 1676: IDENTIFIER_POINTER (DECL_NAME (decl))); 1677: else 1.1.1.2 root 1678: error ("type conversion nonexistent for non-C++ type"); 1.1 root 1679: return 0; 1680: } 1681: if (TREE_CODE (TYPE_NAME (type2)) != TYPE_DECL) 1682: { 1683: tree decl = typedecl_for_tag (type2); 1684: if (decl) 1.1.1.2 root 1685: error ("type conversion nonexistent for type `%s'", 1.1 root 1686: IDENTIFIER_POINTER (decl)); 1687: else 1.1.1.2 root 1688: error ("type conversion nonexistent for non-C++ type"); 1.1 root 1689: return 0; 1690: } 1691: 1692: name1 = TYPE_NAME_STRING (type1); 1693: name2 = TYPE_NAME_STRING (type2); 1694: 1695: if (!IS_AGGR_TYPE (type1) || !TYPE_HAS_CONVERSION (type1)) 1696: { 1697: if (!IS_AGGR_TYPE (type2) || !TYPE_HAS_CONVERSION (type2)) 1698: error ("type conversion required for binary operation on types `%s' and `%s'", 1699: name1, name2); 1700: else 1701: error ("type conversion required for type `%s'", name1); 1702: return 0; 1703: } 1704: else if (!IS_AGGR_TYPE (type2) || !TYPE_HAS_CONVERSION (type2)) 1705: { 1706: error ("type conversion required for type `%s'", name2); 1707: return 0; 1708: } 1709: 1710: if (TYPE_HAS_INT_CONVERSION (type1) && TYPE_HAS_REAL_CONVERSION (type1)) 1711: warning ("ambiguous type conversion for type `%s', defaulting to int", name1); 1712: if (TYPE_HAS_INT_CONVERSION (type1)) 1713: { 1714: *arg1 = build_type_conversion (code, integer_type_node, *arg1, 1); 1715: *arg2 = build_type_conversion (code, integer_type_node, *arg2, 1); 1716: } 1717: else if (TYPE_HAS_REAL_CONVERSION (type1)) 1718: { 1719: *arg1 = build_type_conversion (code, double_type_node, *arg1, 1); 1720: *arg2 = build_type_conversion (code, double_type_node, *arg2, 1); 1721: } 1722: else 1723: { 1724: *arg1 = build_type_conversion (code, ptr_type_node, *arg1, 1); 1725: if (*arg1 == error_mark_node) 1726: error ("ambiguous pointer conversion"); 1727: *arg2 = build_type_conversion (code, ptr_type_node, *arg2, 1); 1728: if (*arg1 != error_mark_node && *arg2 == error_mark_node) 1729: error ("ambiguous pointer conversion"); 1730: } 1731: if (*arg1 == 0) 1732: { 1733: if (*arg2 == 0 && type1 != type2) 1734: error ("default type conversion for types `%s' and `%s' failed", 1735: name1, name2); 1736: else 1737: error ("default type conversion for type `%s' failed", name1); 1738: return 0; 1739: } 1740: else if (*arg2 == 0) 1741: { 1742: error ("default type conversion for type `%s' failed", name2); 1743: return 0; 1744: } 1745: return 1; 1746: } 1747: 1748: /* Must convert two aggregate types to non-aggregate type. 1749: Attempts to find a non-ambiguous, "best" type conversion. 1750: 1751: Return 1 on success, 0 on failure. 1752: 1753: The type of the argument is expected to be of aggregate type here. 1754: 1755: @@ What are the real semantics of this supposed to be??? */ 1756: int 1757: build_default_unary_type_conversion (code, arg) 1758: enum tree_code code; 1759: tree *arg; 1760: { 1761: tree type = TREE_TYPE (*arg); 1762: tree id = TREE_CODE (TYPE_NAME (type)) == TYPE_DECL 1763: ? TYPE_IDENTIFIER (type) : TYPE_NAME (type); 1764: char *name = IDENTIFIER_POINTER (id); 1765: 1766: if (! TYPE_HAS_CONVERSION (type)) 1767: { 1768: error ("type conversion required for type `%s'", name); 1769: return 0; 1770: } 1771: 1772: if (TYPE_HAS_INT_CONVERSION (type) && TYPE_HAS_REAL_CONVERSION (type)) 1773: warning ("ambiguous type conversion for type `%s', defaulting to int", name); 1774: if (TYPE_HAS_INT_CONVERSION (type)) 1775: *arg = build_type_conversion (code, integer_type_node, *arg, 1); 1776: else if (TYPE_HAS_REAL_CONVERSION (type)) 1777: *arg = build_type_conversion (code, double_type_node, *arg, 1); 1778: else 1779: { 1780: *arg = build_type_conversion (code, ptr_type_node, *arg, 1); 1781: if (*arg == error_mark_node) 1782: error ("ambiguous pointer conversion"); 1783: } 1784: if (*arg == 0) 1785: { 1786: error ("default type conversion for type `%s' failed", name); 1787: return 0; 1788: } 1789: return 1; 1790: }
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