gcc/config/sol2.c

   1 /* General Solaris system support.
   2    Copyright (C) 2004-2018 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
  35 tree solaris_pending_aligns, solaris_pending_inits, solaris_pending_finis;
  36
  37 /* Attach any pending attributes for DECL to the list in *ATTRIBUTES.
  38    Pending attributes come from #pragma or _Pragma, so this code is
  39    only useful in the C family front ends, but it is included in
  40    all languages to avoid changing the target machine initializer
  41    depending on the language.  */
  42
  43 void
  44 solaris_insert_attributes (tree decl, tree *attributes)
  45 {
  46   tree *x, next;
  47
  48   if (solaris_pending_aligns != NULL && TREE_CODE (decl) == VAR_DECL)
  49     for (x = &solaris_pending_aligns; *x; x = &TREE_CHAIN (*x))
  50       {
  51         tree name = TREE_PURPOSE (*x);
  52         tree value = TREE_VALUE (*x);
  53         if (DECL_NAME (decl) == name)
  54           {
  55             if (lookup_attribute ("aligned", DECL_ATTRIBUTES (decl))
  56                 || lookup_attribute ("aligned", *attributes))
  57               warning (0, "ignoring %<#pragma align%> for explicitly "
  58                        "aligned %q+D", decl);
  59             else
  60               *attributes = tree_cons (get_identifier ("aligned"), value,
  61                                        *attributes);
  62             next = TREE_CHAIN (*x);
  63             ggc_free (*x);
  64             *x = next;
  65             break;
  66           }
  67       }
  68
  69   if (solaris_pending_inits != NULL && TREE_CODE (decl) == FUNCTION_DECL)
  70     for (x = &solaris_pending_inits; *x; x = &TREE_CHAIN (*x))
  71       {
  72         tree name = TREE_PURPOSE (*x);
  73         if (DECL_NAME (decl) == name)
  74           {
  75             *attributes = tree_cons (get_identifier ("init"), NULL,
  76                                      *attributes);
  77             TREE_USED (decl) = 1;
  78             DECL_PRESERVE_P (decl) = 1;
  79             next = TREE_CHAIN (*x);
  80             ggc_free (*x);
  81             *x = next;
  82             break;
  83           }
  84       }
  85
  86   if (solaris_pending_finis != NULL && TREE_CODE (decl) == FUNCTION_DECL)
  87     for (x = &solaris_pending_finis; *x; x = &TREE_CHAIN (*x))
  88       {
  89         tree name = TREE_PURPOSE (*x);
  90         if (DECL_NAME (decl) == name)
  91           {
  92             *attributes = tree_cons (get_identifier ("fini"), NULL,
  93                                      *attributes);
  94             TREE_USED (decl) = 1;
  95             DECL_PRESERVE_P (decl) = 1;
  96             next = TREE_CHAIN (*x);
  97             ggc_free (*x);
  98             *x = next;
  99             break;
 100           }
 101       }
 102 }
 103
 104 /* Output initializer or finalizer entries for DECL to FILE.  */
 105
 106 void
 107 solaris_output_init_fini (FILE *file, tree decl)
 108 {
 109   if (lookup_attribute ("init", DECL_ATTRIBUTES (decl)))
 110     {
 111       fprintf (file, "\t.pushsection\t" SECTION_NAME_FORMAT "\n", ".init");
 112       ASM_OUTPUT_CALL (file, decl);
 113       fprintf (file, "\t.popsection\n");
 114     }
 115
 116   if (lookup_attribute ("fini", DECL_ATTRIBUTES (decl)))
 117     {
 118       fprintf (file, "\t.pushsection\t" SECTION_NAME_FORMAT "\n", ".fini");
 119       ASM_OUTPUT_CALL (file, decl);
 120       fprintf (file, "\t.popsection\n");
 121     }
 122 }
 123
 124 /* Emit an assembler directive to set symbol for DECL visibility to
 125    the visibility type VIS, which must not be VISIBILITY_DEFAULT.  */
 126
 127 void
 128 solaris_assemble_visibility (tree decl, int vis ATTRIBUTE_UNUSED)
 129 {
 130 #ifdef HAVE_GAS_HIDDEN
 131   /* Sun as uses .symbolic for STV_PROTECTED.  STV_INTERNAL is marked as
 132      `currently reserved', but the linker treats it like STV_HIDDEN.  Sun
 133      Studio 12.1 cc emits .hidden instead.
 134
 135      There are 3 Sun extensions GCC doesn't yet know about: STV_EXPORTED,
 136      STV_SINGLETON, and STV_ELIMINATE.
 137
 138      See Linker and Libraries Guide, Ch. 2, Link-Editor, Defining
 139      Additional Symbols, and Ch. 7, Object-File Format, Symbol Table
 140      Section.  */
 141
 142   static const char * const visibility_types[] = {
 143     NULL, "symbolic", "hidden", "hidden"
 144   };
 145
 146   const char *name, *type;
 147   tree id = DECL_ASSEMBLER_NAME (decl);
 148
 149   while (IDENTIFIER_TRANSPARENT_ALIAS (id))
 150     id = TREE_CHAIN (id);
 151   name = IDENTIFIER_POINTER (id);
 152   type = visibility_types[vis];
 153
 154   fprintf (asm_out_file, "\t.%s\t", type);
 155   assemble_name (asm_out_file, name);
 156   fprintf (asm_out_file, "\n");
 157 #else
 158   if (!DECL_ARTIFICIAL (decl))
 159     warning (OPT_Wattributes, "visibility attribute not supported "
 160                               "in this configuration; ignored");
 161 #endif
 162 }
 163
 164 /* Group section information entry stored in solaris_comdat_htab.  */
 165
 166 typedef struct comdat_entry
 167 {
 168   const char *name;
 169   unsigned int flags;
 170   tree decl;
 171   const char *sig;
 172 } comdat_entry;
 173
 174 /* Helpers for maintaining solaris_comdat_htab.  */
 175
 176 struct comdat_entry_hasher : nofree_ptr_hash <comdat_entry>
 177 {
 178   static inline hashval_t hash (const comdat_entry *);
 179   static inline bool equal (const comdat_entry *, const comdat_entry *);
 180   static inline void remove (comdat_entry *);
 181 };
 182
 183 inline hashval_t
 184 comdat_entry_hasher::hash (const comdat_entry *entry)
 185 {
 186   return htab_hash_string (entry->sig);
 187 }
 188
 189 inline bool
 190 comdat_entry_hasher::equal (const comdat_entry *entry1,
 191                             const comdat_entry *entry2)
 192 {
 193   return strcmp (entry1->sig, entry2->sig) == 0;
 194 }
 195
 196 /* Hash table of group signature symbols.  */
 197
 198 static hash_table<comdat_entry_hasher> *solaris_comdat_htab;
 199
 200 /* Output assembly to switch to COMDAT group section NAME with attributes
 201    FLAGS and group signature symbol DECL, using Sun as syntax.  */
 202
 203 void
 204 solaris_elf_asm_comdat_section (const char *name, unsigned int flags, tree decl)
 205 {
 206   const char *signature;
 207   char *section;
 208   comdat_entry entry, **slot;
 209
 210   if (TREE_CODE (decl) == IDENTIFIER_NODE)
 211     signature = IDENTIFIER_POINTER (decl);
 212   else
 213     signature = IDENTIFIER_POINTER (DECL_COMDAT_GROUP (decl));
 214
 215   /* Sun as requires group sections to be fragmented, i.e. to have names of
 216      the form <section>%<fragment>.  Strictly speaking this is only
 217      necessary to support cc -xF, but is enforced globally in violation of
 218      the ELF gABI.  We keep the section names generated by GCC (generally
 219      of the form .text.<signature>) and append %<signature> to pacify as,
 220      despite the redundancy.  */
 221   section = concat (name, "%", signature, NULL);
 222
 223   /* Clear SECTION_LINKONCE flag so targetm.asm_out.named_section only
 224      emits this as a regular section.  Emit section before .group
 225      directive since Sun as treats undeclared sections as @progbits,
 226      which conflicts with .bss* sections which are @nobits.  */
 227   targetm.asm_out.named_section (section, flags & ~SECTION_LINKONCE, decl);
 228
 229   /* Sun as separates declaration of a group section and of the group
 230      itself, using the .group directive and the #comdat flag.  */
 231   fprintf (asm_out_file, "\t.group\t%s," SECTION_NAME_FORMAT ",#comdat\n",
 232            signature, section);
 233
 234   /* Unlike GNU as, group signature symbols need to be defined explicitly
 235      for Sun as.  With a few exceptions, this is already the case.  To
 236      identify the missing ones without changing the affected frontents,
 237      remember the signature symbols and emit those not marked
 238      TREE_SYMBOL_REFERENCED in solaris_file_end.  */
 239   if (!solaris_comdat_htab)
 240     solaris_comdat_htab = new hash_table<comdat_entry_hasher> (37);
 241
 242   entry.sig = signature;
 243   slot = solaris_comdat_htab->find_slot (&entry, INSERT);
 244
 245   if (*slot == NULL)
 246     {
 247       *slot = XCNEW (comdat_entry);
 248       /* Remember fragmented section name.  */
 249       (*slot)->name = section;
 250       /* Emit as regular section, .group declaration has already been done.  */
 251       (*slot)->flags = flags & ~SECTION_LINKONCE;
 252       (*slot)->decl = decl;
 253       (*slot)->sig = signature;
 254     }
 255 }
 256
 257 /* Define unreferenced COMDAT group signature symbol corresponding to SLOT.  */
 258
 259 int
 260 solaris_define_comdat_signature (comdat_entry **slot,
 261                                  void *aux ATTRIBUTE_UNUSED)
 262 {
 263   comdat_entry *entry = *slot;
 264   tree decl = entry->decl;
 265
 266   if (TREE_CODE (decl) != IDENTIFIER_NODE)
 267     decl = DECL_COMDAT_GROUP (decl);
 268
 269   if (!TREE_SYMBOL_REFERENCED (decl))
 270     {
 271       /* Switch to group section, otherwise Sun as complains
 272          `Group Id symbol defined outside of group'.  */
 273       switch_to_section (get_section (entry->name, entry->flags, entry->decl));
 274
 275       ASM_OUTPUT_LABEL (asm_out_file, entry->sig);
 276     }
 277
 278   /* Continue with scan.  */
 279   return 1;
 280 }
 281
 282 /* Emit unreferenced COMDAT group signature symbols for Sun as.  */
 283
 284 void
 285 solaris_file_end (void)
 286 {
 287   if (!solaris_comdat_htab)
 288     return;
 289
 290   solaris_comdat_htab->traverse <void *, solaris_define_comdat_signature>
 291     (NULL);
 292 }
 293
 294 void
 295 solaris_override_options (void)
 296 {
 297   /* Older versions of Solaris ld cannot handle CIE version 3 in .eh_frame.
 298      Don't emit DWARF3/4 unless specifically selected if so.  */
 299   if (!HAVE_LD_EH_FRAME_CIEV3 && !global_options_set.x_dwarf_version)
 300     dwarf_version = 2;
 301 }