Update.

2002-01-03  Jakub Jelinek  <jakub@redhat.com>

	* elf/Makefile (routines, shared-only-routines): Add
	unwind-dw2-fde-glibc instead of unwind-dw2-fde.
	* elf/elf.h (PT_GNU_EH_FRAME): Define.
	* sysdeps/generic/unwind-dw2-fde-glibc.c: New file.
	* sysdeps/generic/unwind-dw2-fde.c (__register_frame_info_bases):
	Optimize if .eh_frame section contains no FDEs.
	(__register_frame, __deregister_frame_info_bases,
	__deregister_frame): Likewise.
	* sysdeps/generic/unwind-dw2.c (execute_cfa_program): Fix
	DW_CFA_restore handling.

2002-01-07  Stephen L Moshier  <moshier@mediaone.net>

3 files changed, 301 insertions, 6 deletions

diff --git a/sysdeps/generic/unwind-dw2-fde-glibc.c b/sysdeps/generic/unwind-dw2-fde-glibc.c
new file mode 100644
index 0000000..05344cb
--- /dev/null
+++ 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
diff --git a/sysdeps/generic/unwind-dw2-fde.c b/sysdeps/generic/unwind-dw2-fde.c
index 54a0dc1..3d19318 100644
--- a/sysdeps/generic/unwind-dw2-fde.c
+++ b/sysdeps/generic/unwind-dw2-fde.c
@@ -101,6 +101,10 @@ void
 __register_frame_info_bases (void *begin, struct object *ob,
 			     void *tbase, void *dbase)
 {
+  /* If .eh_frame is empty, don't register at all.  */
+  if (*(uword *)begin == 0)
+    return;
+
   ob->pc_begin = (void *)-1;
   ob->tbase = tbase;
   ob->dbase = dbase;
@@ -126,7 +130,13 @@ __register_frame_info (void *begin, struct object *ob)
 void
 __register_frame (void *begin)
 {
-  struct object *ob = (struct object *) malloc (sizeof (struct object));
+  struct object *ob;
+
+  /* If .eh_frame is empty, don't register at all.  */
+  if (*(uword *)begin == 0)
+    return;
+
+  ob = (struct object *) malloc (sizeof (struct object));
   __register_frame_info (begin, ob);
 }
 
@@ -186,6 +196,10 @@ __deregister_frame_info_bases (void *begin)
   struct object **p;
   struct object *ob = 0;
 
+  /* If .eh_frame is empty, we haven't registered.  */
+  if (*(uword *)begin == 0)
+    return ob;
+
   init_object_mutex_once ();
   __gthread_mutex_lock (&object_mutex);
 
@@ -235,7 +249,9 @@ __deregister_frame_info (void *begin)
 void
 __deregister_frame (void *begin)
 {
-  free (__deregister_frame_info (begin));
+  /* If .eh_frame is empty, we haven't registered.  */
+  if (*(uword *)begin != 0)
+    free (__deregister_frame_info (begin));
 }
 
 
@@ -968,7 +984,7 @@ _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
   __gthread_mutex_lock (&object_mutex);
 
   /* Linear search through the classified objects, to find the one
-     containing the pc.  Note that pc_begin is sorted decending, and
+     containing the pc.  Note that pc_begin is sorted descending, and
      we expect objects to be non-overlapping.  */
   for (ob = seen_objects; ob; ob = ob->next)
     if (pc >= ob->pc_begin)
diff --git a/sysdeps/generic/unwind-dw2.c b/sysdeps/generic/unwind-dw2.c
index ac56e7c..ca02994 100644
--- a/sysdeps/generic/unwind-dw2.c
+++ b/sysdeps/generic/unwind-dw2.c
@@ -721,9 +721,9 @@ execute_cfa_program (const unsigned char *insn_ptr,
       _Unwind_Sword offset;
       _Unwind_Ptr ptrtmp;
 
-      if (insn & DW_CFA_advance_loc)
+      if ((insn & 0xc0) == DW_CFA_advance_loc)
 	fs->pc += (insn & 0x3f) * fs->code_align;
-      else if (insn & DW_CFA_offset)
+      else if ((insn & 0xc0) == DW_CFA_offset)
 	{
 	  reg = insn & 0x3f;
 	  insn_ptr = read_uleb128 (insn_ptr, &ptrtmp);
@@ -731,7 +731,7 @@ execute_cfa_program (const unsigned char *insn_ptr,
 	  fs->regs.reg[reg].how = REG_SAVED_OFFSET;
 	  fs->regs.reg[reg].loc.offset = offset;
 	}
-      else if (insn & DW_CFA_restore)
+      else if ((insn & 0xc0) == DW_CFA_restore)
 	{
 	  reg = insn & 0x3f;
 	  fs->regs.reg[reg].how = REG_UNSAVED;