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1 : /*------------------------------------------------------------------------- 2 : * 3 : * jit.c 4 : * Provider independent JIT infrastructure. 5 : * 6 : * Code related to loading JIT providers, redirecting calls into JIT providers 7 : * and error handling. No code specific to a specific JIT implementation 8 : * should end up here. 9 : * 10 : * 11 : * Copyright (c) 2016-2023, PostgreSQL Global Development Group 12 : * 13 : * IDENTIFICATION 14 : * src/backend/jit/jit.c 15 : * 16 : *------------------------------------------------------------------------- 17 : */ 18 : #include "postgres.h" 19 : 20 : #include <sys/types.h> 21 : #include <sys/stat.h> 22 : #include <unistd.h> 23 : 24 : #include "executor/execExpr.h" 25 : #include "fmgr.h" 26 : #include "jit/jit.h" 27 : #include "miscadmin.h" 28 : #include "utils/fmgrprotos.h" 29 : #include "utils/resowner_private.h" 30 : 31 : /* GUCs */ 32 : bool jit_enabled = true; 33 : char *jit_provider = NULL; 34 : bool jit_debugging_support = false; 35 : bool jit_dump_bitcode = false; 36 : bool jit_expressions = true; 37 : bool jit_profiling_support = false; 38 : bool jit_tuple_deforming = true; 39 : double jit_above_cost = 100000; 40 : double jit_inline_above_cost = 500000; 41 : double jit_optimize_above_cost = 500000; 42 : 43 : static JitProviderCallbacks provider; 44 : static bool provider_successfully_loaded = false; 45 : static bool provider_failed_loading = false; 46 : 47 : 48 : static bool provider_init(void); 49 : static bool file_exists(const char *name); 50 : 51 : 52 : /* 53 : * SQL level function returning whether JIT is available in the current 54 : * backend. Will attempt to load JIT provider if necessary. 55 : */ 56 : Datum 57 0 : pg_jit_available(PG_FUNCTION_ARGS) 58 : { 59 0 : PG_RETURN_BOOL(provider_init()); 60 : } 61 : 62 : 63 : /* 64 : * Return whether a JIT provider has successfully been loaded, caching the 65 : * result. 66 : */ 67 : static bool 68 10308 : provider_init(void) 69 : { 70 : char path[MAXPGPATH]; 71 : JitProviderInit init; 72 : 73 : /* don't even try to load if not enabled */ 74 10308 : if (!jit_enabled) 75 0 : return false; 76 : 77 : /* 78 : * Don't retry loading after failing - attempting to load JIT provider 79 : * isn't cheap. 80 : */ 81 10308 : if (provider_failed_loading) 82 0 : return false; 83 10308 : if (provider_successfully_loaded) 84 9530 : return true; 85 : 86 : /* 87 : * Check whether shared library exists. We do that check before actually 88 : * attempting to load the shared library (via load_external_function()), 89 : * because that'd error out in case the shlib isn't available. 90 : */ 91 778 : snprintf(path, MAXPGPATH, "%s/%s%s", pkglib_path, jit_provider, DLSUFFIX); 92 778 : elog(DEBUG1, "probing availability of JIT provider at %s", path); 93 778 : if (!file_exists(path)) 94 : { 95 0 : elog(DEBUG1, 96 : "provider not available, disabling JIT for current session"); 97 0 : provider_failed_loading = true; 98 0 : return false; 99 : } 100 : 101 : /* 102 : * If loading functions fails, signal failure. We do so because 103 : * load_external_function() might error out despite the above check if 104 : * e.g. the library's dependencies aren't installed. We want to signal 105 : * ERROR in that case, so the user is notified, but we don't want to 106 : * continually retry. 107 : */ 108 778 : provider_failed_loading = true; 109 : 110 : /* and initialize */ 111 778 : init = (JitProviderInit) 112 778 : load_external_function(path, "_PG_jit_provider_init", true, NULL); 113 778 : init(&provider); 114 : 115 778 : provider_successfully_loaded = true; 116 778 : provider_failed_loading = false; 117 : 118 778 : elog(DEBUG1, "successfully loaded JIT provider in current session"); 119 : 120 778 : return true; 121 : } 122 : 123 : /* 124 : * Reset JIT provider's error handling. This'll be called after an error has 125 : * been thrown and the main-loop has re-established control. 126 : */ 127 : void 128 35384 : jit_reset_after_error(void) 129 : { 130 35384 : if (provider_successfully_loaded) 131 2802 : provider.reset_after_error(); 132 35384 : } 133 : 134 : /* 135 : * Release resources required by one JIT context. 136 : */ 137 : void 138 1670 : jit_release_context(JitContext *context) 139 : { 140 1670 : if (provider_successfully_loaded) 141 1670 : provider.release_context(context); 142 : 143 1670 : ResourceOwnerForgetJIT(context->resowner, PointerGetDatum(context)); 144 1670 : pfree(context); 145 1670 : } 146 : 147 : /* 148 : * Ask provider to JIT compile an expression. 149 : * 150 : * Returns true if successful, false if not. 151 : */ 152 : bool 153 2177170 : jit_compile_expr(struct ExprState *state) 154 : { 155 : /* 156 : * We can easily create a one-off context for functions without an 157 : * associated PlanState (and thus EState). But because there's no executor 158 : * shutdown callback that could deallocate the created function, they'd 159 : * live to the end of the transactions, where they'd be cleaned up by the 160 : * resowner machinery. That can lead to a noticeable amount of memory 161 : * usage, and worse, trigger some quadratic behaviour in gdb. Therefore, 162 : * at least for now, don't create a JITed function in those circumstances. 163 : */ 164 2177170 : if (!state->parent) 165 776716 : return false; 166 : 167 : /* if no jitting should be performed at all */ 168 1400454 : if (!(state->parent->state->es_jit_flags & PGJIT_PERFORM)) 169 1390146 : return false; 170 : 171 : /* or if expressions aren't JITed */ 172 10308 : if (!(state->parent->state->es_jit_flags & PGJIT_EXPR)) 173 0 : return false; 174 : 175 : /* this also takes !jit_enabled into account */ 176 10308 : if (provider_init()) 177 10308 : return provider.compile_expr(state); 178 : 179 0 : return false; 180 : } 181 : 182 : /* Aggregate JIT instrumentation information */ 183 : void 184 96 : InstrJitAgg(JitInstrumentation *dst, JitInstrumentation *add) 185 : { 186 96 : dst->created_functions += add->created_functions; 187 96 : INSTR_TIME_ADD(dst->generation_counter, add->generation_counter); 188 96 : INSTR_TIME_ADD(dst->inlining_counter, add->inlining_counter); 189 96 : INSTR_TIME_ADD(dst->optimization_counter, add->optimization_counter); 190 96 : INSTR_TIME_ADD(dst->emission_counter, add->emission_counter); 191 96 : } 192 : 193 : static bool 194 778 : file_exists(const char *name) 195 : { 196 : struct stat st; 197 : 198 : Assert(name != NULL); 199 : 200 778 : if (stat(name, &st) == 0) 201 778 : return !S_ISDIR(st.st_mode); 202 0 : else if (!(errno == ENOENT || errno == ENOTDIR)) 203 0 : ereport(ERROR, 204 : (errcode_for_file_access(), 205 : errmsg("could not access file \"%s\": %m", name))); 206 : 207 0 : return false; 208 : }