gcc/d/d-target.cc

   1 /* d-target.cc -- Target interface for the D front end.
   2    Copyright (C) 2013-2024 Free Software Foundation, Inc.
   3
   4 GCC is free software; you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation; either version 3, or (at your option)
   7 any later version.
   8
   9 GCC 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 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with GCC; see the file COPYING3.  If not see
  16 <http://www.gnu.org/licenses/>.  */
  17
  18 #include "config.h"
  19 #include "system.h"
  20 #include "coretypes.h"
  21
  22 #include "dmd/aggregate.h"
  23 #include "dmd/declaration.h"
  24 #include "dmd/expression.h"
  25 #include "dmd/mangle.h"
  26 #include "dmd/mtype.h"
  27 #include "dmd/tokens.h"
  28 #include "dmd/target.h"
  29
  30 #include "tree.h"
  31 #include "memmodel.h"
  32 #include "fold-const.h"
  33 #include "diagnostic.h"
  34 #include "stor-layout.h"
  35 #include "tm.h"
  36 #include "tm_p.h"
  37 #include "target.h"
  38 #include "calls.h"
  39
  40 #include "d-tree.h"
  41 #include "d-target.h"
  42
  43 /* Implements the Target interface defined by the front end.
  44    Used for retrieving target-specific information.  */
  45
  46 /* Internal key handlers for `__traits(getTargetInfo)'.  */
  47 static tree d_handle_target_cpp_std (void);
  48 static tree d_handle_target_cpp_runtime_library (void);
  49 static tree d_handle_target_object_format (void);
  50
  51 /* In [traits/getTargetInfo], a reliable subset of getTargetInfo keys exists
  52    which are always available.  */
  53 static const struct d_target_info_spec d_language_target_info[] =
  54 {
  55   /* { name, handler } */
  56   { "cppStd", d_handle_target_cpp_std },
  57   { "cppRuntimeLibrary", d_handle_target_cpp_runtime_library },
  58   { "floatAbi", NULL },
  59   { "objectFormat", d_handle_target_object_format },
  60   { NULL, NULL },
  61 };
  62
  63 /* Table `__traits(getTargetInfo)' keys.  */
  64 static vec<d_target_info_spec> d_target_info_table;
  65
  66
  67 /* Initialize the floating-point constants for TYPE.  */
  68
  69 template <typename T>
  70 static void
  71 define_float_constants (T &f, tree type)
  72 {
  73   const double log10_2 = 0.30102999566398119521;
  74   char buf[128];
  75
  76   /* Get back-end real mode format.  */
  77   const machine_mode mode = TYPE_MODE (type);
  78   const real_format *fmt = REAL_MODE_FORMAT (mode);
  79
  80   /* The largest representable value that's not infinity.  */
  81   get_max_float (fmt, buf, sizeof (buf), false);
  82   real_from_string (&f.max.rv (), buf);
  83
  84   /* The smallest representable normalized value that's not 0.  */
  85   snprintf (buf, sizeof (buf), "0x1p%d", fmt->emin - 1);
  86   real_from_string (&f.min_normal.rv (), buf);
  87
  88   /* Floating-point NaN.  */
  89   real_nan (&f.nan.rv (), "", 1, mode);
  90
  91   /* Floating-point +Infinity if the target supports infinities.  */
  92   real_inf (&f.infinity.rv ());
  93
  94   /* The smallest increment to the value 1.  */
  95   if (fmt->pnan < fmt->p)
  96     snprintf (buf, sizeof (buf), "0x1p%d", fmt->emin - fmt->p);
  97   else
  98     snprintf (buf, sizeof (buf), "0x1p%d", 1 - fmt->p);
  99   real_from_string (&f.epsilon.rv (), buf);
 100
 101   /* The number of decimal digits of precision.  */
 102   f.dig = (fmt->p - 1) * log10_2;
 103
 104   /* The number of bits in mantissa.  */
 105   f.mant_dig = fmt->p;
 106
 107   /* The maximum int value such that 2** (value-1) is representable.  */
 108   f.max_exp = fmt->emax;
 109
 110   /* The minimum int value such that 2** (value-1) is representable as a
 111      normalized value.  */
 112   f.min_exp = fmt->emin;
 113
 114   /* The maximum int value such that 10**value is representable.  */
 115   f.max_10_exp = fmt->emax * log10_2;
 116
 117   /* The minimum int value such that 10**value is representable as a
 118      normalized value.  */
 119   f.min_10_exp = (fmt->emin - 1) * log10_2;
 120 }
 121
 122 /* Initialize all variables of the Target structure.  */
 123
 124 void
 125 Target::_init (const Param &)
 126 {
 127   /* Map D frontend type and sizes to GCC back-end types.  */
 128   this->ptrsize = (POINTER_SIZE / BITS_PER_UNIT);
 129   this->realsize = int_size_in_bytes (long_double_type_node);
 130   this->realpad = (this->realsize -
 131                    (TYPE_PRECISION (long_double_type_node) / BITS_PER_UNIT));
 132   this->realalignsize = TYPE_ALIGN_UNIT (long_double_type_node);
 133
 134   /* Much of the dmd front-end uses ints for sizes and offsets, and cannot
 135      handle any larger data type without some pervasive rework.  */
 136   this->maxStaticDataSize = tree_to_shwi (TYPE_MAX_VALUE (integer_type_node));
 137
 138   /* Define what type to use for size_t, ptrdiff_t.  */
 139   if (this->ptrsize == 8)
 140     {
 141       this->isLP64 = true;
 142       Type::tsize_t = Type::basic[(int)TY::Tuns64];
 143       Type::tptrdiff_t = Type::basic[(int)TY::Tint64];
 144     }
 145   else if (this->ptrsize == 4)
 146     {
 147       Type::tsize_t = Type::basic[(int)TY::Tuns32];
 148       Type::tptrdiff_t = Type::basic[(int)TY::Tint32];
 149     }
 150   else if (this->ptrsize == 2)
 151     {
 152       Type::tsize_t = Type::basic[(int)TY::Tuns16];
 153       Type::tptrdiff_t = Type::basic[(int)TY::Tint16];
 154     }
 155   else
 156     sorry ("D does not support pointers on this target.");
 157
 158   Type::thash_t = Type::tsize_t;
 159
 160   /* Set-up target C ABI.  */
 161   this->c.boolsize = (BOOL_TYPE_SIZE / BITS_PER_UNIT);
 162   this->c.shortsize = (SHORT_TYPE_SIZE / BITS_PER_UNIT);
 163   this->c.intsize = (INT_TYPE_SIZE / BITS_PER_UNIT);
 164   this->c.longsize = (LONG_TYPE_SIZE / BITS_PER_UNIT);
 165   this->c.long_longsize = (LONG_LONG_TYPE_SIZE / BITS_PER_UNIT);
 166   this->c.long_doublesize = (LONG_DOUBLE_TYPE_SIZE / BITS_PER_UNIT);
 167   this->c.wchar_tsize = (WCHAR_TYPE_SIZE / BITS_PER_UNIT);
 168
 169   this->c.bitFieldStyle = targetm.ms_bitfield_layout_p (unknown_type_node)
 170     ? TargetC::BitFieldStyle::MS : TargetC::BitFieldStyle::Gcc_Clang;
 171
 172   /* Set-up target C++ ABI.  */
 173   this->cpp.reverseOverloads = false;
 174   this->cpp.exceptions = true;
 175   this->cpp.twoDtorInVtable = true;
 176
 177   /* Set-up target Objective-C ABI.  */
 178   this->objc.supported = false;
 179
 180   /* Set-up environmental settings.  */
 181   this->obj_ext = "o";
 182   this->lib_ext = "a";
 183   this->dll_ext = "so";
 184   this->run_noext = true;
 185
 186   /* Initialize all compile-time properties for floating-point types.
 187      Should ensure that our real_t type is able to represent real_value.  */
 188   gcc_assert (sizeof (real_t) >= sizeof (real_value));
 189
 190   define_float_constants (this->FloatProperties, float_type_node);
 191   define_float_constants (this->DoubleProperties, double_type_node);
 192   define_float_constants (this->RealProperties, long_double_type_node);
 193
 194   /* Commonly used floating-point constants.  */
 195   const machine_mode mode = TYPE_MODE (long_double_type_node);
 196   real_convert (&CTFloat::zero.rv (), mode, &dconst0);
 197   real_convert (&CTFloat::one.rv (), mode, &dconst1);
 198   real_convert (&CTFloat::minusone.rv (), mode, &dconstm1);
 199   real_convert (&CTFloat::half.rv (), mode, &dconsthalf);
 200
 201   /* Initialize target info tables, the keys required by the language are added
 202      last, so that the OS and CPU handlers can override.  */
 203   targetdm.d_register_cpu_target_info ();
 204   targetdm.d_register_os_target_info ();
 205   d_add_target_info_handlers (d_language_target_info);
 206 }
 207
 208 /* Return GCC memory alignment size for type TYPE.  */
 209
 210 unsigned
 211 Target::alignsize (Type *type)
 212 {
 213   gcc_assert (type->isTypeBasic ());
 214   return min_align_of_type (build_ctype (type));
 215 }
 216
 217 /* Return GCC field alignment size for type TYPE.  */
 218
 219 unsigned
 220 Target::fieldalign (Type *type)
 221 {
 222   /* Work out the correct alignment for the field decl.  */
 223   unsigned int align = type->alignsize () * BITS_PER_UNIT;
 224
 225 #ifdef BIGGEST_FIELD_ALIGNMENT
 226   align = MIN (align, (unsigned) BIGGEST_FIELD_ALIGNMENT);
 227 #endif
 228
 229 #ifdef ADJUST_FIELD_ALIGN
 230   if (type->isTypeBasic ())
 231     align = ADJUST_FIELD_ALIGN (NULL_TREE, build_ctype (type), align);
 232 #endif
 233
 234   /* Also controlled by -fpack-struct=  */
 235   if (maximum_field_alignment)
 236     align = MIN (align, maximum_field_alignment);
 237
 238   return align / BITS_PER_UNIT;
 239 }
 240
 241 /* Returns a Type for the va_list type of the target.  */
 242
 243 Type *
 244 Target::va_listType (const Loc &, Scope *)
 245 {
 246   if (this->tvalist)
 247     return this->tvalist;
 248
 249   /* Build the "standard" abi va_list.  */
 250   this->tvalist = build_frontend_type (va_list_type_node);
 251   if (!this->tvalist)
 252     sorry ("cannot represent built-in %<va_list%> type in D");
 253
 254   /* Map the va_list type to the D frontend Type.  This is to prevent both
 255      errors in gimplification or an ICE in targetm.canonical_va_list_type.  */
 256   this->tvalist->ctype = va_list_type_node;
 257   TYPE_LANG_SPECIFIC (va_list_type_node) = build_lang_type (this->tvalist);
 258
 259   return this->tvalist;
 260 }
 261
 262 /* Checks whether the target supports a vector type with total size SZ
 263    (in bytes) and element type TYPE.  */
 264
 265 int
 266 Target::isVectorTypeSupported (int sz, Type *type)
 267 {
 268   /* Size must be greater than zero, and a power of two.  */
 269   if (sz <= 0 || sz & (sz - 1))
 270     return 3;
 271
 272   /* __vector(void[]) is treated same as __vector(ubyte[])  */
 273   if (type == Type::tvoid)
 274     type = Type::tuns8;
 275
 276   /* No support for non-trivial types, complex types, or booleans.  */
 277   if (!type->isTypeBasic () || type->iscomplex () || type->ty == TY::Tbool)
 278     return 2;
 279
 280   /* In [simd/vector extensions], which vector types are supported depends on
 281      the target.  The implementation is expected to only support the vector
 282      types that are implemented in the target's hardware.  */
 283   unsigned HOST_WIDE_INT nunits = sz / type->size ();
 284   tree ctype = build_vector_type (build_ctype (type), nunits);
 285
 286   if (!targetm.vector_mode_supported_p (TYPE_MODE (ctype)))
 287     return 2;
 288
 289   return 0;
 290 }
 291
 292 /* Checks whether the target supports operation OP for vectors of type TYPE.
 293    For binary ops T2 is the type of the right-hand operand.
 294    Returns true if the operation is supported or type is not a vector.  */
 295
 296 bool
 297 Target::isVectorOpSupported (Type *type, EXP op, Type *)
 298 {
 299   if (type->ty != TY::Tvector)
 300     return true;
 301
 302   /* Don't support if type is non-scalar, such as __vector(void[]).  */
 303   if (!type->isscalar ())
 304     return false;
 305
 306   /* Don't support if expression cannot be represented.  */
 307   switch (op)
 308     {
 309     case EXP::pow:
 310     case EXP::powAssign:
 311       /* pow() is lowered as a function call.  */
 312       return false;
 313
 314     case EXP::mod:
 315     case EXP::modAssign:
 316       /* fmod() is lowered as a function call.  */
 317       if (type->isfloating ())
 318         return false;
 319       break;
 320
 321     case EXP::andAnd:
 322     case EXP::orOr:
 323       /* Logical operators must have a result type of bool.  */
 324       return false;
 325
 326     default:
 327       break;
 328     }
 329
 330   return true;
 331 }
 332
 333 /* Return the symbol mangling of S for C++ linkage.  */
 334
 335 const char *
 336 TargetCPP::toMangle (Dsymbol *s)
 337 {
 338   return toCppMangleItanium (s);
 339 }
 340
 341 /* Return the symbol mangling of CD for C++ linkage.  */
 342
 343 const char *
 344 TargetCPP::typeInfoMangle (ClassDeclaration *cd)
 345 {
 346   return cppTypeInfoMangleItanium (cd);
 347 }
 348
 349 /* Get mangle name of a this-adjusting thunk to the function declaration FD
 350    at call offset OFFSET for C++ linkage.  */
 351
 352 const char *
 353 TargetCPP::thunkMangle (FuncDeclaration *fd, int offset)
 354 {
 355   return cppThunkMangleItanium (fd, offset);
 356 }
 357
 358 /* For a vendor-specific type, return a string containing the C++ mangling.
 359    In all other cases, return NULL.  */
 360
 361 const char *
 362 TargetCPP::typeMangle (Type *type)
 363 {
 364   if (type->isTypeBasic () || type->ty == TY::Tvector
 365       || type->ty == TY::Tstruct)
 366     {
 367       tree ctype = build_ctype (type);
 368       return targetm.mangle_type (ctype);
 369     }
 370
 371   return NULL;
 372 }
 373
 374 /* Return the type that will really be used for passing the given parameter
 375    ARG to an extern(C++) function.  */
 376
 377 Type *
 378 TargetCPP::parameterType (Type *type)
 379 {
 380   /* Could be a va_list, which we mangle as a pointer.  */
 381   Type *tvalist = target.va_listType (Loc (), NULL);
 382   if (type->ty == TY::Tsarray && tvalist->ty == TY::Tsarray)
 383     {
 384       Type *tb = type->toBasetype ()->mutableOf ();
 385       if (tb == tvalist)
 386         {
 387           tb = type->nextOf ()->pointerTo ();
 388           type = tb->castMod (type->mod);
 389         }
 390     }
 391
 392   return type;
 393 }
 394
 395 /* Checks whether TYPE is a vendor-specific fundamental type.  Stores the result
 396    in IS_FUNDAMENTAL and returns true if the parameter was set.  */
 397
 398 bool
 399 TargetCPP::fundamentalType (const Type *, bool &)
 400 {
 401   return false;
 402 }
 403
 404 /* Get the starting offset position for fields of an `extern(C++)` class
 405    that is derived from the given BASE_CLASS.  */
 406
 407 unsigned
 408 TargetCPP::derivedClassOffset(ClassDeclaration *base_class)
 409 {
 410   return base_class->structsize;
 411 }
 412
 413 /* Return the default `extern (System)' linkage for the target.  */
 414
 415 LINK
 416 Target::systemLinkage (void)
 417 {
 418   unsigned link_system, link_windows;
 419
 420   if (targetdm.d_has_stdcall_convention (&link_system, &link_windows))
 421     {
 422       /* In [attribute/linkage], `System' is the same as `Windows' on Windows
 423          platforms, and `C' on other platforms.  */
 424       if (link_system)
 425         return LINK::windows;
 426     }
 427
 428   return LINK::c;
 429 }
 430
 431 /* Generate a TypeTuple of the equivalent types used to determine if a
 432    function argument of the given type can be passed in registers.
 433    The results of this are highly platform dependent, and intended
 434    primarly for use in implementing va_arg() with RTTI.  */
 435
 436 TypeTuple *
 437 Target::toArgTypes (Type *)
 438 {
 439   /* Not implemented, however this is not currently used anywhere.  */
 440   return NULL;
 441 }
 442
 443 /* Determine return style of function, whether in registers or through a
 444    hidden pointer to the caller's stack.  */
 445
 446 bool
 447 Target::isReturnOnStack (TypeFunction *tf, bool)
 448 {
 449   /* Need the back-end type to determine this, but this is called from the
 450      frontend before semantic processing is finished.  An accurate value
 451      is not currently needed anyway.  */
 452   if (tf->isref ())
 453     return false;
 454
 455   Type *tn = tf->next->toBasetype ();
 456   if (tn->size () == SIZE_INVALID)
 457     return false;
 458
 459   return (tn->ty == TY::Tstruct || tn->ty == TY::Tsarray);
 460 }
 461
 462 /* Add all target info in HANDLERS to D_TARGET_INFO_TABLE for use by
 463    Target::getTargetInfo().  */
 464
 465 void
 466 d_add_target_info_handlers (const d_target_info_spec *handlers)
 467 {
 468   gcc_assert (handlers != NULL);
 469
 470   if (d_target_info_table.is_empty ())
 471     d_target_info_table.create (8);
 472
 473   for (size_t i = 0; handlers[i].name != NULL; i++)
 474     d_target_info_table.safe_push (handlers[i]);
 475 }
 476
 477 /* Handle a call to `__traits(getTargetInfo, "cppStd")'.  */
 478
 479 tree
 480 d_handle_target_cpp_std (void)
 481 {
 482   return build_integer_cst (global.params.cplusplus);
 483 }
 484
 485 /* Handle a call to `__traits(getTargetInfo, "cppRuntimeLibrary")'.  */
 486
 487 tree
 488 d_handle_target_cpp_runtime_library (void)
 489 {
 490   /* The driver only ever optionally links to libstdc++.  */
 491   const char *libstdcxx = "libstdc++";
 492   return build_string_literal (strlen (libstdcxx) + 1, libstdcxx);
 493 }
 494
 495 /* Handle a call to `__traits(getTargetInfo, "objectFormat")'.  */
 496
 497 tree
 498 d_handle_target_object_format (void)
 499 {
 500   const char *objfmt;
 501
 502 #ifdef OBJECT_FORMAT_ELF
 503   objfmt = "elf";
 504 #else
 505   if (TARGET_COFF || TARGET_PECOFF)
 506     objfmt = "coff";
 507   else
 508     objfmt = "";
 509 #endif
 510
 511   return build_string_literal (strlen (objfmt) + 1, objfmt);
 512 }
 513
 514 /* Look up the target info KEY in the available getTargetInfo tables, and return
 515    the result as an Expression, or NULL if KEY is not found.  When the key must
 516    always exist, but is not supported, an empty string expression is returned.
 517    LOC is the location to use for the returned expression.  */
 518
 519 Expression *
 520 Target::getTargetInfo (const char *key, const Loc &loc)
 521 {
 522   unsigned ix;
 523   d_target_info_spec *spec;
 524
 525   FOR_EACH_VEC_ELT (d_target_info_table, ix, spec)
 526     {
 527       tree result;
 528
 529       if (strcmp (key, spec->name) != 0)
 530         continue;
 531
 532       /* Get the requested information, or empty string if unhandled.  */
 533       if (spec->handler)
 534         {
 535           result = (spec->handler) ();
 536           /* Handler didn't return a result, meaning it really does not support
 537              the key in the current target configuration.  Check whether there
 538              are any other handlers which may recognize the key.  */
 539           if (result == NULL_TREE)
 540             continue;
 541         }
 542       else
 543         result = build_string_literal (1, "");
 544
 545       gcc_assert (result);
 546       return d_eval_constant_expression (loc, result);
 547     }
 548
 549   return NULL;
 550 }
 551
 552 /* Returns true if the callee invokes destructors for arguments.  */
 553
 554 bool
 555 Target::isCalleeDestroyingArgs (TypeFunction *tf)
 556 {
 557   return tf->linkage == LINK::d;
 558 }
 559
 560 /* Returns true if the implementation for object monitors is always defined
 561    in the D runtime library (rt/monitor_.d).  */
 562
 563 bool
 564 Target::libraryObjectMonitors (FuncDeclaration *, Statement *)
 565 {
 566   return true;
 567 }
 568
 569 /* Returns true if the target supports `pragma(linkerDirective)'.  */
 570
 571 bool
 572 Target::supportsLinkerDirective (void) const
 573 {
 574   return false;
 575 }
 576
 577 /* Decides whether an `in' parameter of the specified POD type PARAM_TYPE is to
 578    be passed by reference or by valie.  This is used only when compiling with
 579    `-fpreview=in' enabled.  */
 580
 581 bool
 582 Target::preferPassByRef (Type *param_type)
 583 {
 584   if (param_type->size () == SIZE_INVALID)
 585     return false;
 586
 587   tree type = build_ctype (param_type);
 588
 589   /* Prefer a `ref' if the type is an aggregate, and its size is greater than
 590      its alignment.  */
 591   if (AGGREGATE_TYPE_P (type)
 592       && (!valid_constant_size_p (TYPE_SIZE_UNIT (type))
 593           || compare_tree_int (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type)) > 0))
 594     return true;
 595
 596   /* If the back-end is always going to pass this by invisible reference.  */
 597   if (pass_by_reference (NULL, function_arg_info (type, true)))
 598     return true;
 599
 600   /* If returning the parameter means the caller will do RVO.  */
 601   if (targetm.calls.return_in_memory (type, NULL_TREE))
 602     return true;
 603
 604   return false;
 605 }