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-rw-r--r--sysdeps/generic/unwind-dw2-fde-glibc.c279
1 files changed, 279 insertions, 0 deletions
diff --git a/sysdeps/generic/unwind-dw2-fde-glibc.c b/sysdeps/generic/unwind-dw2-fde-glibc.c
new file mode 100644
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+++ b/sysdeps/generic/unwind-dw2-fde-glibc.c
@@ -0,0 +1,279 @@
+/* Copyright (C) 2001 Free Software Foundation, Inc.
+ Contributed by Jakub Jelinek <jakub@redhat.com>.
+
+ This file is part of GNU CC.
+
+ GNU CC is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ GNU CC 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with GNU CC; see the file COPYING. If not, write to
+ the Free Software Foundation, 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+/* As a special exception, if you link this library with other files,
+ some of which are compiled with GCC, to produce an executable,
+ this library does not by itself cause the resulting executable
+ to be covered by the GNU General Public License.
+ This exception does not however invalidate any other reasons why
+ the executable file might be covered by the GNU General Public License. */
+
+/* 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
+
+fde * _Unwind_Find_registered_FDE (void *pc, struct dwarf_eh_bases *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, *p_dynamic;
+ 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);
+ read_encoded_value_with_base (encoding,
+ base_from_cb_data (encoding, data),
+ data->ret->pc_begin,
+ (_Unwind_Ptr *)&data->func);
+ }
+ return 1;
+}
+
+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
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