Line data Source code
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) 2016-2025, 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 "fmgr.h" 25 : #include "jit/jit.h" 26 : #include "miscadmin.h" 27 : #include "nodes/execnodes.h" 28 : #include "portability/instr_time.h" 29 : #include "utils/fmgrprotos.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 : 50 : 51 : /* 52 : * SQL level function returning whether JIT is available in the current 53 : * backend. Will attempt to load JIT provider if necessary. 54 : */ 55 : Datum 56 0 : pg_jit_available(PG_FUNCTION_ARGS) 57 : { 58 0 : PG_RETURN_BOOL(provider_init()); 59 : } 60 : 61 : 62 : /* 63 : * Return whether a JIT provider has successfully been loaded, caching the 64 : * result. 65 : */ 66 : static bool 67 9060 : provider_init(void) 68 : { 69 : char path[MAXPGPATH]; 70 : JitProviderInit init; 71 : 72 : /* don't even try to load if not enabled */ 73 9060 : if (!jit_enabled) 74 0 : return false; 75 : 76 : /* 77 : * Don't retry loading after failing - attempting to load JIT provider 78 : * isn't cheap. 79 : */ 80 9060 : if (provider_failed_loading) 81 0 : return false; 82 9060 : if (provider_successfully_loaded) 83 8584 : return true; 84 : 85 : /* 86 : * Check whether shared library exists. We do that check before actually 87 : * attempting to load the shared library (via load_external_function()), 88 : * because that'd error out in case the shlib isn't available. 89 : */ 90 476 : snprintf(path, MAXPGPATH, "%s/%s%s", pkglib_path, jit_provider, DLSUFFIX); 91 476 : elog(DEBUG1, "probing availability of JIT provider at %s", path); 92 476 : if (!pg_file_exists(path)) 93 : { 94 0 : elog(DEBUG1, 95 : "provider not available, disabling JIT for current session"); 96 0 : provider_failed_loading = true; 97 0 : return false; 98 : } 99 : 100 : /* 101 : * If loading functions fails, signal failure. We do so because 102 : * load_external_function() might error out despite the above check if 103 : * e.g. the library's dependencies aren't installed. We want to signal 104 : * ERROR in that case, so the user is notified, but we don't want to 105 : * continually retry. 106 : */ 107 476 : provider_failed_loading = true; 108 : 109 : /* and initialize */ 110 476 : init = (JitProviderInit) 111 476 : load_external_function(path, "_PG_jit_provider_init", true, NULL); 112 476 : init(&provider); 113 : 114 476 : provider_successfully_loaded = true; 115 476 : provider_failed_loading = false; 116 : 117 476 : elog(DEBUG1, "successfully loaded JIT provider in current session"); 118 : 119 476 : return true; 120 : } 121 : 122 : /* 123 : * Reset JIT provider's error handling. This'll be called after an error has 124 : * been thrown and the main-loop has re-established control. 125 : */ 126 : void 127 41590 : jit_reset_after_error(void) 128 : { 129 41590 : if (provider_successfully_loaded) 130 3998 : provider.reset_after_error(); 131 41590 : } 132 : 133 : /* 134 : * Release resources required by one JIT context. 135 : */ 136 : void 137 1222 : jit_release_context(JitContext *context) 138 : { 139 1222 : if (provider_successfully_loaded) 140 1222 : provider.release_context(context); 141 : 142 1222 : pfree(context); 143 1222 : } 144 : 145 : /* 146 : * Ask provider to JIT compile an expression. 147 : * 148 : * Returns true if successful, false if not. 149 : */ 150 : bool 151 2286218 : jit_compile_expr(struct ExprState *state) 152 : { 153 : /* 154 : * We can easily create a one-off context for functions without an 155 : * associated PlanState (and thus EState). But because there's no executor 156 : * shutdown callback that could deallocate the created function, they'd 157 : * live to the end of the transactions, where they'd be cleaned up by the 158 : * resowner machinery. That can lead to a noticeable amount of memory 159 : * usage, and worse, trigger some quadratic behaviour in gdb. Therefore, 160 : * at least for now, don't create a JITed function in those circumstances. 161 : */ 162 2286218 : if (!state->parent) 163 661046 : return false; 164 : 165 : /* if no jitting should be performed at all */ 166 1625172 : if (!(state->parent->state->es_jit_flags & PGJIT_PERFORM)) 167 1616112 : return false; 168 : 169 : /* or if expressions aren't JITed */ 170 9060 : if (!(state->parent->state->es_jit_flags & PGJIT_EXPR)) 171 0 : return false; 172 : 173 : /* this also takes !jit_enabled into account */ 174 9060 : if (provider_init()) 175 9060 : return provider.compile_expr(state); 176 : 177 0 : return false; 178 : } 179 : 180 : /* Aggregate JIT instrumentation information */ 181 : void 182 96 : InstrJitAgg(JitInstrumentation *dst, JitInstrumentation *add) 183 : { 184 96 : dst->created_functions += add->created_functions; 185 96 : INSTR_TIME_ADD(dst->generation_counter, add->generation_counter); 186 96 : INSTR_TIME_ADD(dst->deform_counter, add->deform_counter); 187 96 : INSTR_TIME_ADD(dst->inlining_counter, add->inlining_counter); 188 96 : INSTR_TIME_ADD(dst->optimization_counter, add->optimization_counter); 189 96 : INSTR_TIME_ADD(dst->emission_counter, add->emission_counter); 190 96 : }