diff options
Diffstat (limited to 'REORG.TODO/sysdeps/generic/unwind-dw2-fde-glibc.c')
| -rw-r--r-- | REORG.TODO/sysdeps/generic/unwind-dw2-fde-glibc.c | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/generic/unwind-dw2-fde-glibc.c b/REORG.TODO/sysdeps/generic/unwind-dw2-fde-glibc.c new file mode 100644 index 0000000000..9d698d575b --- /dev/null +++ b/REORG.TODO/sysdeps/generic/unwind-dw2-fde-glibc.c @@ -0,0 +1,279 @@ +/* Copyright (C) 2001-2017 Free Software Foundation, Inc. + Contributed by Jakub Jelinek <jakub@redhat.com>. + + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +/* Locate the FDE entry for a given address, using PT_GNU_EH_FRAME ELF + segment and dl_iterate_phdr to avoid register/deregister calls at + DSO load/unload. */ + +#ifdef _LIBC +# include <shlib-compat.h> +#endif + +#if !defined _LIBC || SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_2_5) + +#include <link.h> +#include <stddef.h> + +#define _Unwind_Find_FDE _Unwind_Find_registered_FDE + +#include <unwind-dw2-fde.c> + +#undef _Unwind_Find_FDE + +extern fde * _Unwind_Find_registered_FDE (void *pc, + struct dwarf_eh_bases *bases); +extern fde * _Unwind_Find_FDE (void *, struct dwarf_eh_bases *); + +struct unw_eh_callback_data +{ + _Unwind_Ptr pc; + void *tbase; + void *dbase; + void *func; + fde *ret; +}; + +struct unw_eh_frame_hdr +{ + unsigned char version; + unsigned char eh_frame_ptr_enc; + unsigned char fde_count_enc; + unsigned char table_enc; +}; + +/* Like base_of_encoded_value, but take the base from a struct object + instead of an _Unwind_Context. */ + +static _Unwind_Ptr +base_from_cb_data (unsigned char encoding, struct unw_eh_callback_data *data) +{ + if (encoding == DW_EH_PE_omit) + return 0; + + switch (encoding & 0x70) + { + case DW_EH_PE_absptr: + case DW_EH_PE_pcrel: + case DW_EH_PE_aligned: + return 0; + + case DW_EH_PE_textrel: + return (_Unwind_Ptr) data->tbase; + case DW_EH_PE_datarel: + return (_Unwind_Ptr) data->dbase; + } + abort (); +} + +static int +_Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr) +{ + struct unw_eh_callback_data *data = (struct unw_eh_callback_data *) ptr; + const ElfW(Phdr) *phdr, *p_eh_frame_hdr; + const ElfW(Phdr) *p_dynamic __attribute__ ((unused)); + long n, match; + _Unwind_Ptr load_base; + const unsigned char *p; + const struct unw_eh_frame_hdr *hdr; + _Unwind_Ptr eh_frame; + struct object ob; + + /* Make sure struct dl_phdr_info is at least as big as we need. */ + if (size < offsetof (struct dl_phdr_info, dlpi_phnum) + + sizeof (info->dlpi_phnum)) + return -1; + + match = 0; + phdr = info->dlpi_phdr; + load_base = info->dlpi_addr; + p_eh_frame_hdr = NULL; + p_dynamic = NULL; + + /* See if PC falls into one of the loaded segments. Find the eh_frame + segment at the same time. */ + for (n = info->dlpi_phnum; --n >= 0; phdr++) + { + if (phdr->p_type == PT_LOAD) + { + _Unwind_Ptr vaddr = phdr->p_vaddr + load_base; + if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz) + match = 1; + } + else if (phdr->p_type == PT_GNU_EH_FRAME) + p_eh_frame_hdr = phdr; + else if (phdr->p_type == PT_DYNAMIC) + p_dynamic = phdr; + } + if (!match || !p_eh_frame_hdr) + return 0; + + /* Read .eh_frame_hdr header. */ + hdr = (const struct unw_eh_frame_hdr *) + (p_eh_frame_hdr->p_vaddr + load_base); + if (hdr->version != 1) + return 1; + +#ifdef CRT_GET_RFIB_DATA +# ifdef __i386__ + data->dbase = NULL; + if (p_dynamic) + { + /* For dynamicly linked executables and shared libraries, + DT_PLTGOT is the gp value for that object. */ + ElfW(Dyn) *dyn = (ElfW(Dyn) *)(p_dynamic->p_vaddr + load_base); + for (; dyn->d_tag != DT_NULL ; dyn++) + if (dyn->d_tag == DT_PLTGOT) + { + /* On IA-32, _DYNAMIC is writable and GLIBC has relocated it. */ + data->dbase = (void *) dyn->d_un.d_ptr; + break; + } + } +# else +# error What is DW_EH_PE_datarel base on this platform? +# endif +#endif +#ifdef CRT_GET_RFIB_TEXT +# error What is DW_EH_PE_textrel base on this platform? +#endif + + p = read_encoded_value_with_base (hdr->eh_frame_ptr_enc, + base_from_cb_data (hdr->eh_frame_ptr_enc, + data), + (const unsigned char *) (hdr + 1), + &eh_frame); + + /* We require here specific table encoding to speed things up. + Also, DW_EH_PE_datarel here means using PT_GNU_EH_FRAME start + as base, not the processor specific DW_EH_PE_datarel. */ + if (hdr->fde_count_enc != DW_EH_PE_omit + && hdr->table_enc == (DW_EH_PE_datarel | DW_EH_PE_sdata4)) + { + _Unwind_Ptr fde_count; + + p = read_encoded_value_with_base (hdr->fde_count_enc, + base_from_cb_data (hdr->fde_count_enc, + data), + p, &fde_count); + /* Shouldn't happen. */ + if (fde_count == 0) + return 1; + if ((((_Unwind_Ptr) p) & 3) == 0) + { + struct fde_table { + signed initial_loc __attribute__ ((mode (SI))); + signed fde __attribute__ ((mode (SI))); + }; + const struct fde_table *table = (const struct fde_table *) p; + size_t lo, hi, mid; + _Unwind_Ptr data_base = (_Unwind_Ptr) hdr; + fde *f; + unsigned int f_enc, f_enc_size; + _Unwind_Ptr range; + + mid = fde_count - 1; + if (data->pc < table[0].initial_loc + data_base) + return 1; + else if (data->pc < table[mid].initial_loc + data_base) + { + lo = 0; + hi = mid; + + while (lo < hi) + { + mid = (lo + hi) / 2; + if (data->pc < table[mid].initial_loc + data_base) + hi = mid; + else if (data->pc >= table[mid + 1].initial_loc + data_base) + lo = mid + 1; + else + break; + } + + if (lo >= hi) + __gxx_abort (); + } + + f = (fde *) (table[mid].fde + data_base); + f_enc = get_fde_encoding (f); + f_enc_size = size_of_encoded_value (f_enc); + read_encoded_value_with_base (f_enc & 0x0f, 0, + &f->pc_begin[f_enc_size], &range); + if (data->pc < table[mid].initial_loc + data_base + range) + data->ret = f; + data->func = (void *) (table[mid].initial_loc + data_base); + return 1; + } + } + + /* We have no sorted search table, so need to go the slow way. + As soon as GLIBC will provide API so to notify that a library has been + removed, we could cache this (and thus use search_object). */ + ob.pc_begin = NULL; + ob.tbase = data->tbase; + ob.dbase = data->dbase; + ob.u.single = (fde *) eh_frame; + ob.s.i = 0; + ob.s.b.mixed_encoding = 1; /* Need to assume worst case. */ + data->ret = linear_search_fdes (&ob, (fde *) eh_frame, (void *) data->pc); + if (data->ret != NULL) + { + unsigned int encoding = get_fde_encoding (data->ret); + _Unwind_Ptr func; + read_encoded_value_with_base (encoding, + base_from_cb_data (encoding, data), + data->ret->pc_begin, &func); + data->func = (void *) func; + } + return 1; +} + +# ifdef _LIBC +# define dl_iterate_phdr __dl_iterate_phdr +# endif + +fde * +_Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases) +{ + struct unw_eh_callback_data data; + fde *ret; + + ret = _Unwind_Find_registered_FDE (pc, bases); + if (ret != NULL) + return ret; + + data.pc = (_Unwind_Ptr) pc; + data.tbase = NULL; + data.dbase = NULL; + data.func = NULL; + data.ret = NULL; + + if (dl_iterate_phdr (_Unwind_IteratePhdrCallback, &data) < 0) + return NULL; + + if (data.ret) + { + bases->tbase = data.tbase; + bases->dbase = data.dbase; + bases->func = data.func; + } + return data.ret; +} + +#endif |