gcc/config/sol2.cc

   1 /* General Solaris system support.
   2    Copyright (C) 2004-2023 Free Software Foundation, Inc.
   3    Contributed by CodeSourcery, LLC.
   4
   5 This file is part of GCC.
   6
   7 GCC 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 3, or (at your option)
  10 any later version.
  11
  12 GCC 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 GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "target.h"
  25 #include "rtl.h"
  26 #include "tree.h"
  27 #include "memmodel.h"
  28 #include "tm_p.h"
  29 #include "stringpool.h"
  30 #include "attribs.h"
  31 #include "diagnostic-core.h"
  32 #include "varasm.h"
  33 #include "output.h"
  34 #include "opts.h"
  35
  36 tree solaris_pending_aligns, solaris_pending_inits, solaris_pending_finis;
  37
  38 /* Attach any pending attributes for DECL to the list in *ATTRIBUTES.
  39    Pending attributes come from #pragma or _Pragma, so this code is
  40    only useful in the C family front ends, but it is included in
  41    all languages to avoid changing the target machine initializer
  42    depending on the language.  */
  43
  44 void
  45 solaris_insert_attributes (tree decl, tree *attributes)
  46 {
  47   tree *x, next;
  48
  49   if (solaris_pending_aligns != NULL && TREE_CODE (decl) == VAR_DECL)
  50     for (x = &solaris_pending_aligns; *x; x = &TREE_CHAIN (*x))
  51       {
  52         tree name = TREE_PURPOSE (*x);
  53         tree value = TREE_VALUE (*x);
  54         if (DECL_NAME (decl) == name)
  55           {
  56             if (lookup_attribute ("aligned", DECL_ATTRIBUTES (decl))
  57                 || lookup_attribute ("aligned", *attributes))
  58               warning (0, "ignoring %<#pragma align%> for explicitly "
  59                        "aligned %q+D", decl);
  60             else
  61               *attributes = tree_cons (get_identifier ("aligned"), value,
  62                                        *attributes);
  63             next = TREE_CHAIN (*x);
  64             ggc_free (*x);
  65             *x = next;
  66             break;
  67           }
  68       }
  69
  70   if (solaris_pending_inits != NULL && TREE_CODE (decl) == FUNCTION_DECL)
  71     for (x = &solaris_pending_inits; *x; x = &TREE_CHAIN (*x))
  72       {
  73         tree name = TREE_PURPOSE (*x);
  74         if (DECL_NAME (decl) == name)
  75           {
  76             *attributes = tree_cons (get_identifier ("init"), NULL,
  77                                      *attributes);
  78             TREE_USED (decl) = 1;
  79             DECL_PRESERVE_P (decl) = 1;
  80             next = TREE_CHAIN (*x);
  81             ggc_free (*x);
  82             *x = next;
  83             break;
  84           }
  85       }
  86
  87   if (solaris_pending_finis != NULL && TREE_CODE (decl) == FUNCTION_DECL)
  88     for (x = &solaris_pending_finis; *x; x = &TREE_CHAIN (*x))
  89       {
  90         tree name = TREE_PURPOSE (*x);
  91         if (DECL_NAME (decl) == name)
  92           {
  93             *attributes = tree_cons (get_identifier ("fini"), NULL,
  94                                      *attributes);
  95             TREE_USED (decl) = 1;
  96             DECL_PRESERVE_P (decl) = 1;
  97             next = TREE_CHAIN (*x);
  98             ggc_free (*x);
  99             *x = next;
 100             break;
 101           }
 102       }
 103 }
 104
 105 /* Output initializer or finalizer entries for DECL to FILE.  */
 106
 107 void
 108 solaris_output_init_fini (FILE *file, tree decl)
 109 {
 110   if (lookup_attribute ("init", DECL_ATTRIBUTES (decl)))
 111     {
 112       fprintf (file, "\t.pushsection\t" SECTION_NAME_FORMAT "\n", ".init");
 113       ASM_OUTPUT_CALL (file, decl);
 114       fprintf (file, "\t.popsection\n");
 115     }
 116
 117   if (lookup_attribute ("fini", DECL_ATTRIBUTES (decl)))
 118     {
 119       fprintf (file, "\t.pushsection\t" SECTION_NAME_FORMAT "\n", ".fini");
 120       ASM_OUTPUT_CALL (file, decl);
 121       fprintf (file, "\t.popsection\n");
 122     }
 123 }
 124
 125 /* Emit an assembler directive to set symbol for DECL visibility to
 126    the visibility type VIS, which must not be VISIBILITY_DEFAULT.  */
 127
 128 void
 129 solaris_assemble_visibility (tree decl, int vis ATTRIBUTE_UNUSED)
 130 {
 131 #ifdef HAVE_GAS_HIDDEN
 132   /* Sun as uses .symbolic for STV_PROTECTED.  STV_INTERNAL is marked as
 133      `currently reserved', but the linker treats it like STV_HIDDEN.  Sun
 134      Studio 12.1 cc emits .hidden instead.
 135
 136      There are 3 Sun extensions GCC doesn't yet know about: STV_EXPORTED,
 137      STV_SINGLETON, and STV_ELIMINATE.
 138
 139      See Linker and Libraries Guide, Ch. 2, Link-Editor, Defining
 140      Additional Symbols, and Ch. 7, Object-File Format, Symbol Table
 141      Section.  */
 142
 143   static const char * const visibility_types[] = {
 144     NULL, "symbolic", "hidden", "hidden"
 145   };
 146
 147   const char *name, *type;
 148   tree id = DECL_ASSEMBLER_NAME (decl);
 149
 150   while (IDENTIFIER_TRANSPARENT_ALIAS (id))
 151     id = TREE_CHAIN (id);
 152   name = IDENTIFIER_POINTER (id);
 153   type = visibility_types[vis];
 154
 155   fprintf (asm_out_file, "\t.%s\t", type);
 156   assemble_name (asm_out_file, name);
 157   fprintf (asm_out_file, "\n");
 158 #else
 159   if (!DECL_ARTIFICIAL (decl))
 160     warning (OPT_Wattributes, "visibility attribute not supported "
 161                               "in this configuration; ignored");
 162 #endif
 163 }
 164
 165 /* Group section information entry stored in solaris_comdat_htab.  */
 166
 167 typedef struct comdat_entry
 168 {
 169   const char *name;
 170   unsigned int flags;
 171   tree decl;
 172   const char *sig;
 173 } comdat_entry;
 174
 175 /* Helpers for maintaining solaris_comdat_htab.  */
 176
 177 struct comdat_entry_hasher : nofree_ptr_hash <comdat_entry>
 178 {
 179   static inline hashval_t hash (const comdat_entry *);
 180   static inline bool equal (const comdat_entry *, const comdat_entry *);
 181   static inline void remove (comdat_entry *);
 182 };
 183
 184 inline hashval_t
 185 comdat_entry_hasher::hash (const comdat_entry *entry)
 186 {
 187   return htab_hash_string (entry->sig);
 188 }
 189
 190 inline bool
 191 comdat_entry_hasher::equal (const comdat_entry *entry1,
 192                             const comdat_entry *entry2)
 193 {
 194   return strcmp (entry1->sig, entry2->sig) == 0;
 195 }
 196
 197 /* Hash table of group signature symbols.  */
 198
 199 static hash_table<comdat_entry_hasher> *solaris_comdat_htab;
 200
 201 /* Output assembly to switch to COMDAT group section NAME with attributes
 202    FLAGS and group signature symbol DECL, using Sun as syntax.  */
 203
 204 void
 205 solaris_elf_asm_comdat_section (const char *name, unsigned int flags, tree decl)
 206 {
 207   const char *signature;
 208   char *section;
 209   comdat_entry entry, **slot;
 210
 211   if (TREE_CODE (decl) == IDENTIFIER_NODE)
 212     signature = IDENTIFIER_POINTER (decl);
 213   else
 214     signature = IDENTIFIER_POINTER (DECL_COMDAT_GROUP (decl));
 215
 216   /* Sun as requires group sections to be fragmented, i.e. to have names of
 217      the form <section>%<fragment>.  Strictly speaking this is only
 218      necessary to support cc -xF, but is enforced globally in violation of
 219      the ELF gABI.  We keep the section names generated by GCC (generally
 220      of the form .text.<signature>) and append %<signature> to pacify as,
 221      despite the redundancy.  */
 222   section = concat (name, "%", signature, NULL);
 223
 224   /* Clear SECTION_LINKONCE flag so targetm.asm_out.named_section only
 225      emits this as a regular section.  Emit section before .group
 226      directive since Sun as treats undeclared sections as @progbits,
 227      which conflicts with .bss* sections which are @nobits.  */
 228   targetm.asm_out.named_section (section, flags & ~SECTION_LINKONCE, decl);
 229
 230   /* Sun as separates declaration of a group section and of the group
 231      itself, using the .group directive and the #comdat flag.  */
 232   fprintf (asm_out_file, "\t.group\t%s," SECTION_NAME_FORMAT ",#comdat\n",
 233            signature, section);
 234
 235   /* Unlike GNU as, group signature symbols need to be defined explicitly
 236      for Sun as.  With a few exceptions, this is already the case.  To
 237      identify the missing ones without changing the affected frontents,
 238      remember the signature symbols and emit those not marked
 239      TREE_SYMBOL_REFERENCED in solaris_file_end.  */
 240   if (!solaris_comdat_htab)
 241     solaris_comdat_htab = new hash_table<comdat_entry_hasher> (37);
 242
 243   entry.sig = signature;
 244   slot = solaris_comdat_htab->find_slot (&entry, INSERT);
 245
 246   if (*slot == NULL)
 247     {
 248       *slot = XCNEW (comdat_entry);
 249       /* Remember fragmented section name.  */
 250       (*slot)->name = section;
 251       /* Emit as regular section, .group declaration has already been done.  */
 252       (*slot)->flags = flags & ~SECTION_LINKONCE;
 253       (*slot)->decl = decl;
 254       (*slot)->sig = signature;
 255     }
 256 }
 257
 258 /* Define unreferenced COMDAT group signature symbol corresponding to SLOT.  */
 259
 260 int
 261 solaris_define_comdat_signature (comdat_entry **slot,
 262                                  void *aux ATTRIBUTE_UNUSED)
 263 {
 264   comdat_entry *entry = *slot;
 265   tree decl = entry->decl;
 266
 267   if (TREE_CODE (decl) != IDENTIFIER_NODE)
 268     decl = DECL_COMDAT_GROUP (decl);
 269
 270   if (!TREE_SYMBOL_REFERENCED (decl))
 271     {
 272       /* Switch to group section, otherwise Sun as complains
 273          `Group Id symbol defined outside of group'.  */
 274       switch_to_section (get_section (entry->name, entry->flags, entry->decl));
 275
 276       ASM_OUTPUT_LABEL (asm_out_file, entry->sig);
 277     }
 278
 279   /* Continue with scan.  */
 280   return 1;
 281 }
 282
 283 /* Emit unreferenced COMDAT group signature symbols for Sun as.  */
 284
 285 void
 286 solaris_file_end (void)
 287 {
 288   if (!solaris_comdat_htab)
 289     return;
 290
 291   solaris_comdat_htab->traverse <void *, solaris_define_comdat_signature>
 292     (NULL);
 293 }
 294
 295 void
 296 solaris_override_options (void)
 297 {
 298   /* Older versions of Solaris ld cannot handle CIE version 3 in .eh_frame.
 299      Don't emit DWARF3/4 unless specifically selected if so.  */
 300   if (!HAVE_LD_EH_FRAME_CIEV3 && !OPTION_SET_P (dwarf_version))
 301     dwarf_version = 2;
 302 }