ladybird/Userland/Libraries/LibC/sys/internals.h
Daniel Bertalan ad9e674fa0 LibC+LibELF: Support loading shared libraries compiled with dynamic TLS
This is a prerequisite for upstreaming our LLVM patches, as our current
hack forcing `-ftls-model=initial-exec` in the Clang driver is not
acceptable upstream.

Currently, our kernel-managed TLS implementation limits us to only
having a single block of storage for all thread-local variables that's
initialized at load time. This PR merely implements the dynamic TLS
interface (`__tls_get_addr` and TLSDESC) on top of our static TLS
infrastructure. The current model's limitations still stand:
- a single static TLS block is reserved at load time, `dlopen()`-ing
  shared libraries that define thread-local variables might cause us to
  run out of space.
- the initial TLS image is not changeable post-load, so `dlopen()`-ing
  libraries with non-zero-initialized TLS variables is not supported.

The way we repurpose `ti_module` to mean "offset within static TLS
block" instead of "module index" is not ABI-compliant.
2023-08-18 16:20:13 +02:00

39 lines
957 B
C

/*
* Copyright (c) 2020-2023, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <sys/cdefs.h>
#include <sys/types.h>
__BEGIN_DECLS
typedef void (*AtExitFunction)(void*);
extern void __libc_init(void);
extern void __malloc_init(void);
extern void __stdio_init(void);
extern void __begin_atexit_locking(void);
extern void _init(void);
extern bool __environ_is_malloced;
extern bool __stdio_is_initialized;
extern bool __heap_is_stable;
extern void* __auxiliary_vector;
int __cxa_atexit(AtExitFunction exit_function, void* parameter, void* dso_handle);
void __cxa_finalize(void* dso_handle);
__attribute__((noreturn)) void __cxa_pure_virtual(void) __attribute__((weak));
__attribute__((noreturn)) void __stack_chk_fail(void);
__attribute__((noreturn)) void __stack_chk_fail_local(void);
struct __tls_index {
size_t ti_module;
size_t ti_offset;
};
void* __tls_get_addr(__tls_index*);
__END_DECLS