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) 2016-2023, 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             : }