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Diffstat (limited to 'src/backend/jit/jit.c')
| -rw-r--r-- | src/backend/jit/jit.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/src/backend/jit/jit.c b/src/backend/jit/jit.c new file mode 100644 index 0000000..2da300e --- /dev/null +++ b/src/backend/jit/jit.c @@ -0,0 +1,208 @@ +/*------------------------------------------------------------------------- + * + * jit.c + * Provider independent JIT infrastructure. + * + * Code related to loading JIT providers, redirecting calls into JIT providers + * and error handling. No code specific to a specific JIT implementation + * should end up here. + * + * + * Copyright (c) 2016-2021, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/backend/jit/jit.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> + +#include "executor/execExpr.h" +#include "fmgr.h" +#include "jit/jit.h" +#include "miscadmin.h" +#include "utils/fmgrprotos.h" +#include "utils/resowner_private.h" + +/* GUCs */ +bool jit_enabled = true; +char *jit_provider = NULL; +bool jit_debugging_support = false; +bool jit_dump_bitcode = false; +bool jit_expressions = true; +bool jit_profiling_support = false; +bool jit_tuple_deforming = true; +double jit_above_cost = 100000; +double jit_inline_above_cost = 500000; +double jit_optimize_above_cost = 500000; + +static JitProviderCallbacks provider; +static bool provider_successfully_loaded = false; +static bool provider_failed_loading = false; + + +static bool provider_init(void); +static bool file_exists(const char *name); + + +/* + * SQL level function returning whether JIT is available in the current + * backend. Will attempt to load JIT provider if necessary. + */ +Datum +pg_jit_available(PG_FUNCTION_ARGS) +{ + PG_RETURN_BOOL(provider_init()); +} + + +/* + * Return whether a JIT provider has successfully been loaded, caching the + * result. + */ +static bool +provider_init(void) +{ + char path[MAXPGPATH]; + JitProviderInit init; + + /* don't even try to load if not enabled */ + if (!jit_enabled) + return false; + + /* + * Don't retry loading after failing - attempting to load JIT provider + * isn't cheap. + */ + if (provider_failed_loading) + return false; + if (provider_successfully_loaded) + return true; + + /* + * Check whether shared library exists. We do that check before actually + * attempting to load the shared library (via load_external_function()), + * because that'd error out in case the shlib isn't available. + */ + snprintf(path, MAXPGPATH, "%s/%s%s", pkglib_path, jit_provider, DLSUFFIX); + elog(DEBUG1, "probing availability of JIT provider at %s", path); + if (!file_exists(path)) + { + elog(DEBUG1, + "provider not available, disabling JIT for current session"); + provider_failed_loading = true; + return false; + } + + /* + * If loading functions fails, signal failure. We do so because + * load_external_function() might error out despite the above check if + * e.g. the library's dependencies aren't installed. We want to signal + * ERROR in that case, so the user is notified, but we don't want to + * continually retry. + */ + provider_failed_loading = true; + + /* and initialize */ + init = (JitProviderInit) + load_external_function(path, "_PG_jit_provider_init", true, NULL); + init(&provider); + + provider_successfully_loaded = true; + provider_failed_loading = false; + + elog(DEBUG1, "successfully loaded JIT provider in current session"); + + return true; +} + +/* + * Reset JIT provider's error handling. This'll be called after an error has + * been thrown and the main-loop has re-established control. + */ +void +jit_reset_after_error(void) +{ + if (provider_successfully_loaded) + provider.reset_after_error(); +} + +/* + * Release resources required by one JIT context. + */ +void +jit_release_context(JitContext *context) +{ + if (provider_successfully_loaded) + provider.release_context(context); + + ResourceOwnerForgetJIT(context->resowner, PointerGetDatum(context)); + pfree(context); +} + +/* + * Ask provider to JIT compile an expression. + * + * Returns true if successful, false if not. + */ +bool +jit_compile_expr(struct ExprState *state) +{ + /* + * We can easily create a one-off context for functions without an + * associated PlanState (and thus EState). But because there's no executor + * shutdown callback that could deallocate the created function, they'd + * live to the end of the transactions, where they'd be cleaned up by the + * resowner machinery. That can lead to a noticeable amount of memory + * usage, and worse, trigger some quadratic behaviour in gdb. Therefore, + * at least for now, don't create a JITed function in those circumstances. + */ + if (!state->parent) + return false; + + /* if no jitting should be performed at all */ + if (!(state->parent->state->es_jit_flags & PGJIT_PERFORM)) + return false; + + /* or if expressions aren't JITed */ + if (!(state->parent->state->es_jit_flags & PGJIT_EXPR)) + return false; + + /* this also takes !jit_enabled into account */ + if (provider_init()) + return provider.compile_expr(state); + + return false; +} + +/* Aggregate JIT instrumentation information */ +void +InstrJitAgg(JitInstrumentation *dst, JitInstrumentation *add) +{ + dst->created_functions += add->created_functions; + INSTR_TIME_ADD(dst->generation_counter, add->generation_counter); + INSTR_TIME_ADD(dst->inlining_counter, add->inlining_counter); + INSTR_TIME_ADD(dst->optimization_counter, add->optimization_counter); + INSTR_TIME_ADD(dst->emission_counter, add->emission_counter); +} + +static bool +file_exists(const char *name) +{ + struct stat st; + + AssertArg(name != NULL); + + if (stat(name, &st) == 0) + return S_ISDIR(st.st_mode) ? false : true; + else if (!(errno == ENOENT || errno == ENOTDIR)) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not access file \"%s\": %m", name))); + + return false; +} |