1 /* A type-safe hash table template. 2 Copyright (C) 2012-2020 Free Software Foundation, Inc. 3 Contributed by Lawrence Crowl <crowl@google.com> 4 5 This file is part of GCC. 6 7 GCC is free software; you can redistribute it and/or modify it under 8 the terms of the GNU General Public License as published by the Free 9 Software Foundation; either version 3, or (at your option) any later 10 version. 11 12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 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 22 /* This file implements a typed hash table. 23 The implementation borrows from libiberty's hashtab. */ 24 25 #ifdef GENERATOR_FILE 26 #include "bconfig.h" 27 #else 28 #include "config.h" 29 #endif 30 #include "system.h" 31 #include "coretypes.h" 32 #include "hash-table.h" 33 34 /* Table of primes and multiplicative inverses. 35 36 Note that these are not minimally reduced inverses. Unlike when generating 37 code to divide by a constant, we want to be able to use the same algorithm 38 all the time. All of these inverses (are implied to) have bit 32 set. 39 40 For the record, here's the function that computed the table; it's a 41 vastly simplified version of the function of the same name from gcc. */ 42 43 struct prime_ent const prime_tab[] = { 44 { 7, 0x24924925, 0x9999999b, 2 }, 45 { 13, 0x3b13b13c, 0x745d1747, 3 }, 46 { 31, 0x08421085, 0x1a7b9612, 4 }, 47 { 61, 0x0c9714fc, 0x15b1e5f8, 5 }, 48 { 127, 0x02040811, 0x0624dd30, 6 }, 49 { 251, 0x05197f7e, 0x073260a5, 7 }, 50 { 509, 0x01824366, 0x02864fc8, 8 }, 51 { 1021, 0x00c0906d, 0x014191f7, 9 }, 52 { 2039, 0x0121456f, 0x0161e69e, 10 }, 53 { 4093, 0x00300902, 0x00501908, 11 }, 54 { 8191, 0x00080041, 0x00180241, 12 }, 55 { 16381, 0x000c0091, 0x00140191, 13 }, 56 { 32749, 0x002605a5, 0x002a06e6, 14 }, 57 { 65521, 0x000f00e2, 0x00110122, 15 }, 58 { 131071, 0x00008001, 0x00018003, 16 }, 59 { 262139, 0x00014002, 0x0001c004, 17 }, 60 { 524287, 0x00002001, 0x00006001, 18 }, 61 { 1048573, 0x00003001, 0x00005001, 19 }, 62 { 2097143, 0x00004801, 0x00005801, 20 }, 63 { 4194301, 0x00000c01, 0x00001401, 21 }, 64 { 8388593, 0x00001e01, 0x00002201, 22 }, 65 { 16777213, 0x00000301, 0x00000501, 23 }, 66 { 33554393, 0x00001381, 0x00001481, 24 }, 67 { 67108859, 0x00000141, 0x000001c1, 25 }, 68 { 134217689, 0x000004e1, 0x00000521, 26 }, 69 { 268435399, 0x00000391, 0x000003b1, 27 }, 70 { 536870909, 0x00000019, 0x00000029, 28 }, 71 { 1073741789, 0x0000008d, 0x00000095, 29 }, 72 { 2147483647, 0x00000003, 0x00000007, 30 }, 73 /* Avoid "decimal constant so large it is unsigned" for 4294967291. */ 74 { 0xfffffffb, 0x00000006, 0x00000008, 31 } 75 }; 76 77 /* Limit number of comparisons when calling hash_table<>::verify. */ 78 unsigned int hash_table_sanitize_eq_limit; 79 80 /* The following function returns an index into the above table of the 81 nearest prime number which is at least N, and near a power of two. */ 82 83 unsigned int 84 hash_table_higher_prime_index (unsigned long n) 85 { 86 unsigned int low = 0; 87 unsigned int high = sizeof (prime_tab) / sizeof (prime_tab[0]); 88 89 while (low != high) 90 { 91 unsigned int mid = low + (high - low) / 2; 92 if (n > prime_tab[mid].prime) 93 low = mid + 1; 94 else 95 high = mid; 96 } 97 98 /* If we've run out of primes, abort. */ 99 gcc_assert (n <= prime_tab[low].prime); 100 101 return low; 102 } 103 104 /* Return a reference to the lazily initialized hash-table usage description. 105 This needs to be a function rather than a simple global variable so that it 106 is reliably initialized before hash table variables in other files such as 107 sem_item::m_type_hash_cache. */ 108 mem_alloc_description<mem_usage>& 109 hash_table_usage () 110 { 111 static mem_alloc_description<mem_usage> usage; 112 return usage; 113 } 114 115 /* Support function for statistics. */ 116 void dump_hash_table_loc_statistics (void) 117 { 118 if (!GATHER_STATISTICS) 119 return; 120 121 for (unsigned i = HASH_TABLE_ORIGIN; i <= HASH_SET_ORIGIN; i++) 122 { 123 mem_alloc_origin origin = (mem_alloc_origin) i; 124 hash_table_usage ().dump (origin); 125 } 126 } 127 128 /* Report a hash table checking error. */ 129 130 ATTRIBUTE_NORETURN ATTRIBUTE_COLD 131 void 132 hashtab_chk_error () 133 { 134 fprintf (stderr, "hash table checking failed: " 135 "equal operator returns true for a pair " 136 "of values with a different hash value\n"); 137 gcc_unreachable (); 138 } 139