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//===-- sanitizer_tls_get_addr.h --------------------------------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// Handle the __tls_get_addr call.
// All this magic is specific to glibc and is required to workaround
// the lack of interface that would tell us about the Dynamic TLS (DTLS).
// The matters get worse because the glibc implementation changed between
// 2.18 and 2.19:
// Before 2.19, every DTLS chunk is allocated with __libc_memalign,
// which we intercept and thus know where is the DTLS.
// Since 2.19, DTLS chunks are allocated with __signal_safe_memalign,
// which is an internal function that wraps a mmap call, neither of which
// we can intercept. Luckily, __signal_safe_memalign has a simple parseable
// header which we can use.
#include "sanitizer_common.h"
namespace __sanitizer {
struct DTLS {
// Array of DTLS chunks for the current Thread.
// If beg == 0, the chunk is unused.
struct DTV {
uptr beg, size;
uptr dtv_size;
DTV *dtv; // dtv_size elements, allocated by MmapOrDie.
// Auxiliary fields, don't access them outside
uptr last_memalign_size;
uptr last_memalign_ptr;
// Returns pointer and size of a linker-allocated TLS block.
// Each block is returned exactly once.
DTLS::DTV *DTLS_on_tls_get_addr(void *arg, void *res, uptr static_tls_begin,
uptr static_tls_end);
void DTLS_on_libc_memalign(void *ptr, uptr size);
void DTLS_Destroy(); // Make sure to call this before the thread is destroyed.
} // namespace __sanitizer