2004-03-23 Andrew Cagney <cagney@redhat.com>

* tramp-frame.h, tramp-frame.h: New files.
	* Makefile.in (SFILES, tramp_frame_h, COMMON_OBS, tramp-frame.o):
	Update rules to include "tramp-frame.h" and "tramp-frame.c".

gdb/ChangeLog

@@ -1,5 +1,9 @@
 2004-03-23  Andrew Cagney  <cagney@redhat.com>
 
+	* tramp-frame.h, tramp-frame.h: New files.
+	* Makefile.in (SFILES, tramp_frame_h, COMMON_OBS, tramp-frame.o):
+	Update rules to include "tramp-frame.h" and "tramp-frame.c".
+
 	* Makefile.in: Update all dependencies.
 
 2004-03-23  Andrew Cagney  <cagney@redhat.com>

gdb/Makefile.in

@@ -541,6 +541,7 @@ SFILES = ada-exp.y ada-lang.c ada-typeprint.c ada-valprint.c ada-tasks.c \
 	stabsread.c stack.c std-regs.c symfile.c symmisc.c symtab.c \
 	target.c thread.c top.c tracepoint.c \
 	trad-frame.c \
+	tramp-frame.c \
 	typeprint.c \
 	ui-out.c utils.c ui-file.h ui-file.c \
 	user-regs.c \
@@ -757,6 +758,7 @@ terminal_h = terminal.h
 top_h = top.h
 tracepoint_h = tracepoint.h
 trad_frame_h = trad-frame.h $(frame_h)
+tramp_frame_h = tramp-frame.h
 typeprint_h = typeprint.h
 ui_file_h = ui-file.h
 ui_out_h = ui-out.h
@@ -905,7 +907,8 @@ COMMON_OBS = $(DEPFILES) $(YYOBJ) \
 	gnu-v2-abi.o gnu-v3-abi.o hpacc-abi.o cp-abi.o cp-support.o \
 	cp-namespace.o \
 	reggroups.o \
-	trad-frame.o
+	trad-frame.o \
+	tramp-frame.o
 
 TSOBS = inflow.o
 
@@ -2444,6 +2447,9 @@ tracepoint.o: tracepoint.c $(defs_h) $(symtab_h) $(frame_h) $(gdbtypes_h) \
 	$(readline_history_h)
 trad-frame.o: trad-frame.c $(defs_h) $(frame_h) $(trad_frame_h) \
 	$(regcache_h)
+tramp-frame.o: tramp-frame.c $(defs_h) $(tramp_frame_h) $(frame_unwind_h) \
+	$(gdbcore_h) $(symtab_h) $(objfiles_h) $(target_h) $(trad_frame_h) \
+	$(frame_base_h)
 typeprint.o: typeprint.c $(defs_h) $(gdb_obstack_h) $(bfd_h) $(symtab_h) \
 	$(gdbtypes_h) $(expression_h) $(value_h) $(gdbcore_h) $(command_h) \
 	$(gdbcmd_h) $(target_h) $(language_h) $(cp_abi_h) $(typeprint_h) \

gdb/tramp-frame.c

@@ -0,0 +1,162 @@
+/* Signal trampoline unwinder, for GDB the GNU Debugger.
+
+   Copyright 2004 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program 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 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "tramp-frame.h"
+#include "frame-unwind.h"
+#include "gdbcore.h"
+#include "symtab.h"
+#include "objfiles.h"
+#include "target.h"
+#include "trad-frame.h"
+#include "frame-base.h"
+
+struct frame_data
+{
+  const struct tramp_frame *tramp_frame;
+};
+
+struct tramp_frame_cache
+{
+  CORE_ADDR func;
+  const struct tramp_frame *tramp_frame;
+  struct trad_frame_cache *trad_cache;
+};
+
+static struct trad_frame_cache *
+tramp_frame_cache (struct frame_info *next_frame,
+		   void **this_cache)
+{
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  struct tramp_frame_cache *tramp_cache = (*this_cache);
+  if (tramp_cache->trad_cache == NULL)
+    {
+      tramp_cache->trad_cache = trad_frame_cache_zalloc (next_frame);
+      tramp_cache->tramp_frame->init (tramp_cache->tramp_frame,
+				      next_frame,
+				      tramp_cache->trad_cache,
+				      tramp_cache->func);
+    }
+  return tramp_cache->trad_cache;
+}
+
+static void
+tramp_frame_this_id (struct frame_info *next_frame,
+		     void **this_cache,
+		     struct frame_id *this_id)
+{
+  struct trad_frame_cache *trad_cache
+    = tramp_frame_cache (next_frame, this_cache);
+  trad_frame_get_id (trad_cache, this_id);
+}
+
+static void
+tramp_frame_prev_register (struct frame_info *next_frame,
+			   void **this_cache,
+			   int prev_regnum,
+			   int *optimizedp,
+			   enum lval_type * lvalp,
+			   CORE_ADDR *addrp,
+			   int *realnump, void *valuep)
+{
+  struct trad_frame_cache *trad_cache
+    = tramp_frame_cache (next_frame, this_cache);
+  trad_frame_get_register (trad_cache, next_frame, prev_regnum, optimizedp,
+			   lvalp, addrp, realnump, valuep);
+}
+
+static CORE_ADDR
+tramp_frame_start (CORE_ADDR pc, const struct tramp_frame *tramp)
+{
+  int ti;
+  /* Search through the trampoline for one that matches the
+     instruction sequence around PC.  */
+  for (ti = 0; tramp->insn[ti] != 0; ti++)
+    {
+      CORE_ADDR func = pc - tramp->insn_size * ti;
+      int i;
+      for (i = 0; 1; i++)
+	{
+	  bfd_byte buf[sizeof (LONGEST)];
+	  CORE_ADDR insn;
+	  if (tramp->insn[i] == 0)
+	    return func;
+	  if (target_read_memory (func + i * tramp->insn_size, buf,
+				  tramp->insn_size) != 0)
+	    break;
+	  insn = extract_unsigned_integer (buf, tramp->insn_size);
+	  if (tramp->insn[i] != insn)
+	    break;
+	}
+    }
+  /* Trampoline doesn't match.  */
+  return 0;
+}
+
+static int
+tramp_frame_sniffer (const struct frame_unwind *self,
+		     struct frame_info *next_frame,
+		     void **this_cache)
+{
+  const struct tramp_frame *tramp = self->unwind_data->tramp_frame;
+  CORE_ADDR pc = frame_pc_unwind (next_frame);
+  CORE_ADDR func;
+  char *name;
+  struct tramp_frame_cache *tramp_cache;
+
+  /* If the function has a valid symbol name, it isn't a
+     trampoline.  */
+  find_pc_partial_function (pc, &name, NULL, NULL);
+  if (name != NULL)
+    return 0;
+  /* If the function lives in a valid section (even without a starting
+     point) it isn't a trampoline.  */
+  if (find_pc_section (pc) != NULL)
+    return 0;
+  /* Finally, check that the trampoline matches at PC.  */
+  func = tramp_frame_start (pc, tramp);
+  if (func == 0)
+    return 0;
+  tramp_cache = FRAME_OBSTACK_ZALLOC (struct tramp_frame_cache);
+  tramp_cache->func = func;
+  tramp_cache->tramp_frame = tramp;
+  (*this_cache) = tramp_cache;
+  return 1;
+}
+
+void
+tramp_frame_append (struct gdbarch *gdbarch,
+		    const struct tramp_frame *tramp_frame)
+{
+  struct frame_data *data;
+  struct frame_unwind *unwinder;
+
+  data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data);
+  unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind);
+
+  data->tramp_frame = tramp_frame;
+  unwinder->type = SIGTRAMP_FRAME;
+  unwinder->unwind_data = data;
+  unwinder->sniffer = tramp_frame_sniffer;
+  unwinder->this_id = tramp_frame_this_id;
+  unwinder->prev_register = tramp_frame_prev_register;
+  frame_unwind_register_unwinder (gdbarch, unwinder);
+}

gdb/tramp-frame.h

@@ -0,0 +1,64 @@
+/* Signal trampoline unwinder, for GDB the GNU Debugger.
+
+   Copyright 2004 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program 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 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#ifndef TRAMP_FRAME_H
+#define TRAMP_FRAME_H
+
+struct trad_frame;
+struct frame_info;
+struct trad_frame_cache;
+
+/* A trampoline consists of a small sequence of instructions placed at
+   an unspecified location in the inferior's address space.  The only
+   identifying attribute of the trampoline's address is that it does
+   not fall inside an object file's section.
+
+   The only way to identify a trampoline is to perform a brute force
+   examination of the instructions at and around the PC.
+
+   This module provides a convent interface for performing that
+   operation.  */
+
+/* A trampoline descriptor.  */
+
+struct tramp_frame
+{
+  /* The trampoline's entire instruction sequence.  Search for this in
+     the inferior at or around the frame's PC.  It is assumed that the
+     PC is INSN_SIZE aligned, and that each element of TRAMP contains
+     one INSN_SIZE instruction.  It is also assumed that TRAMP[0]
+     contains the first instruction of the trampoline and hence the
+     address of the instruction matching TRAMP[0] is the trampoline's
+     "func" address.  */
+  int insn_size;
+  ULONGEST insn[8];
+  /* Initialize a trad-frame cache corresponding to the tramp-frame.
+     FUNC is the address of the instruction TRAMP[0] in memory.  */
+  void (*init) (const struct tramp_frame *self,
+		struct frame_info *next_frame,
+		struct trad_frame_cache *this_cache,
+		CORE_ADDR func);
+};
+
+void tramp_frame_append (struct gdbarch *gdbarch,
+			 const struct tramp_frame *tramp);
+
+#endif