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/*-------------------------------------------------------------------------
*
* llvmjit_error.cpp
* LLVM error related handling that requires interfacing with C++
*
* Unfortunately neither (re)setting the C++ new handler, nor the LLVM OOM
* handler are exposed to C. Therefore this file wraps the necessary code.
*
* Copyright (c) 2016-2023, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/backend/jit/llvm/llvmjit_error.cpp
*
*-------------------------------------------------------------------------
*/
extern "C"
{
#include "postgres.h"
}
#include <llvm/Support/ErrorHandling.h>
#include "jit/llvmjit.h"
#include <new>
static int fatal_new_handler_depth = 0;
static std::new_handler old_new_handler = NULL;
static void fatal_system_new_handler(void);
#if LLVM_VERSION_MAJOR > 4
static void fatal_llvm_new_handler(void *user_data, const char *reason, bool gen_crash_diag);
#if LLVM_VERSION_MAJOR < 14
static void fatal_llvm_new_handler(void *user_data, const std::string& reason, bool gen_crash_diag);
#endif
#endif
static void fatal_llvm_error_handler(void *user_data, const char *reason, bool gen_crash_diag);
#if LLVM_VERSION_MAJOR < 14
static void fatal_llvm_error_handler(void *user_data, const std::string& reason, bool gen_crash_diag);
#endif
/*
* Enter a section in which C++ and LLVM errors are treated as FATAL errors.
*
* This is necessary for LLVM as LLVM's error handling for such cases
* (exit()ing, throwing std::bad_alloc() if compiled with exceptions, abort())
* isn't compatible with postgres error handling. Thus in sections where LLVM
* code, not LLVM generated functions!, is executing, standard new, LLVM OOM
* and LLVM fatal errors (some OOM errors masquerade as those) are redirected
* to our own error handlers.
*
* These error handlers use FATAL, because there's no reliable way from within
* LLVM to throw an error that's guaranteed not to corrupt LLVM's state.
*
* To avoid disturbing extensions using C++ and/or LLVM, these handlers are
* unset when not executing LLVM code. There is no need to call
* llvm_leave_fatal_on_oom() when ERRORing out, error recovery resets the
* handlers in that case.
*/
void
llvm_enter_fatal_on_oom(void)
{
if (fatal_new_handler_depth == 0)
{
old_new_handler = std::set_new_handler(fatal_system_new_handler);
#if LLVM_VERSION_MAJOR > 4
llvm::install_bad_alloc_error_handler(fatal_llvm_new_handler);
#endif
llvm::install_fatal_error_handler(fatal_llvm_error_handler);
}
fatal_new_handler_depth++;
}
/*
* Leave fatal error section started with llvm_enter_fatal_on_oom().
*/
void
llvm_leave_fatal_on_oom(void)
{
fatal_new_handler_depth--;
if (fatal_new_handler_depth == 0)
{
std::set_new_handler(old_new_handler);
#if LLVM_VERSION_MAJOR > 4
llvm::remove_bad_alloc_error_handler();
#endif
llvm::remove_fatal_error_handler();
}
}
/*
* Are we currently in a fatal-on-oom section? Useful to skip cleanup in case
* of errors.
*/
bool
llvm_in_fatal_on_oom(void)
{
return fatal_new_handler_depth > 0;
}
/*
* Reset fatal error handling. This should only be called in error recovery
* loops like PostgresMain()'s.
*/
void
llvm_reset_after_error(void)
{
if (fatal_new_handler_depth != 0)
{
std::set_new_handler(old_new_handler);
#if LLVM_VERSION_MAJOR > 4
llvm::remove_bad_alloc_error_handler();
#endif
llvm::remove_fatal_error_handler();
}
fatal_new_handler_depth = 0;
}
void
llvm_assert_in_fatal_section(void)
{
Assert(fatal_new_handler_depth > 0);
}
static void
fatal_system_new_handler(void)
{
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("while in LLVM")));
}
#if LLVM_VERSION_MAJOR > 4
static void
fatal_llvm_new_handler(void *user_data,
const char *reason,
bool gen_crash_diag)
{
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("While in LLVM: %s", reason)));
}
#if LLVM_VERSION_MAJOR < 14
static void
fatal_llvm_new_handler(void *user_data,
const std::string& reason,
bool gen_crash_diag)
{
fatal_llvm_new_handler(user_data, reason.c_str(), gen_crash_diag);
}
#endif
#endif
static void
fatal_llvm_error_handler(void *user_data,
const char *reason,
bool gen_crash_diag)
{
ereport(FATAL,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("fatal llvm error: %s", reason)));
}
#if LLVM_VERSION_MAJOR < 14
static void
fatal_llvm_error_handler(void *user_data,
const std::string& reason,
bool gen_crash_diag)
{
fatal_llvm_error_handler(user_data, reason.c_str(), gen_crash_diag);
}
#endif
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