Add branch trace information to struct thread_info.

Add functions to enable, disable, clear, and fetch a thread's branch trace.

gdb/
	* target.h: Include btrace.h.
	(struct target_ops) <to_supports_btrace, to_enable_btrace,
	to_disable_btrace, to_teardown_btrace, to_read_btrace>: New.
	* target.c (target_supports_btrace): New function.
	(target_enable_btrace): New function.
	(target_disable_btrace): New function.
	(target_teardown_btrace): New function.
	(target_read_btrace): New function.
	* btrace.h: New file.
	* btrace.c: New file.
	* Makefile.in: Add btrace.c.
	* gdbthread.h: Include btrace.h.
	(struct thread_info): Add btrace field.
	* thread.c: Include btrace.h.
	(clear_thread_inferior_resources): Call target_teardown_btrace.
	* common/btrace-common.h: New file.

1 files changed, 449 insertions, 0 deletions

diff --git a/gdb/btrace.c b/gdb/btrace.c
new file mode 100644
index 0000000..2acecbe
--- /dev/null
+++ b/gdb/btrace.c
@@ -0,0 +1,449 @@
+/* Branch trace support for GDB, the GNU debugger.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   Contributed by Intel Corp. <markus.t.metzger@intel.com>
+
+   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 3 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, see <http://www.gnu.org/licenses/>.  */
+
+#include "btrace.h"
+#include "gdbthread.h"
+#include "exceptions.h"
+#include "inferior.h"
+#include "target.h"
+#include "record.h"
+#include "symtab.h"
+#include "disasm.h"
+#include "source.h"
+#include "filenames.h"
+
+/* Print a record debug message.  Use do ... while (0) to avoid ambiguities
+   when used in if statements.  */
+
+#define DEBUG(msg, args...)						\
+  do									\
+    {									\
+      if (record_debug != 0)						\
+        fprintf_unfiltered (gdb_stdlog,					\
+			    "[btrace] " msg "\n", ##args);		\
+    }									\
+  while (0)
+
+#define DEBUG_FTRACE(msg, args...) DEBUG ("[ftrace] " msg, ##args)
+
+/* Initialize the instruction iterator.  */
+
+static void
+btrace_init_insn_iterator (struct btrace_thread_info *btinfo)
+{
+  DEBUG ("init insn iterator");
+
+  btinfo->insn_iterator.begin = 1;
+  btinfo->insn_iterator.end = 0;
+}
+
+/* Initialize the function iterator.  */
+
+static void
+btrace_init_func_iterator (struct btrace_thread_info *btinfo)
+{
+  DEBUG ("init func iterator");
+
+  btinfo->func_iterator.begin = 1;
+  btinfo->func_iterator.end = 0;
+}
+
+/* Compute the instruction trace from the block trace.  */
+
+static VEC (btrace_inst_s) *
+compute_itrace (VEC (btrace_block_s) *btrace)
+{
+  VEC (btrace_inst_s) *itrace;
+  struct gdbarch *gdbarch;
+  unsigned int b;
+
+  DEBUG ("compute itrace");
+
+  itrace = NULL;
+  gdbarch = target_gdbarch ();
+  b = VEC_length (btrace_block_s, btrace);
+
+  while (b-- != 0)
+    {
+      btrace_block_s *block;
+      CORE_ADDR pc;
+
+      block = VEC_index (btrace_block_s, btrace, b);
+      pc = block->begin;
+
+      /* Add instructions for this block.  */
+      for (;;)
+	{
+	  btrace_inst_s *inst;
+	  int size;
+
+	  /* We should hit the end of the block.  Warn if we went too far.  */
+	  if (block->end < pc)
+	    {
+	      warning (_("Recorded trace may be corrupted."));
+	      break;
+	    }
+
+	  inst = VEC_safe_push (btrace_inst_s, itrace, NULL);
+	  inst->pc = pc;
+
+	  /* We're done once we pushed the instruction at the end.  */
+	  if (block->end == pc)
+	    break;
+
+	  size = gdb_insn_length (gdbarch, pc);
+
+	  /* Make sure we terminate if we fail to compute the size.  */
+	  if (size <= 0)
+	    {
+	      warning (_("Recorded trace may be incomplete."));
+	      break;
+	    }
+
+	  pc += size;
+	}
+    }
+
+  return itrace;
+}
+
+/* Return the function name of a recorded function segment for printing.
+   This function never returns NULL.  */
+
+static const char *
+ftrace_print_function_name (struct btrace_func *bfun)
+{
+  struct minimal_symbol *msym;
+  struct symbol *sym;
+
+  msym = bfun->msym;
+  sym = bfun->sym;
+
+  if (sym != NULL)
+    return SYMBOL_PRINT_NAME (sym);
+
+  if (msym != NULL)
+    return SYMBOL_PRINT_NAME (msym);
+
+  return "<unknown>";
+}
+
+/* Return the file name of a recorded function segment for printing.
+   This function never returns NULL.  */
+
+static const char *
+ftrace_print_filename (struct btrace_func *bfun)
+{
+  struct symbol *sym;
+  const char *filename;
+
+  sym = bfun->sym;
+
+  if (sym != NULL)
+    filename = symtab_to_filename_for_display (sym->symtab);
+  else
+    filename = "<unknown>";
+
+  return filename;
+}
+
+/* Print an ftrace debug status message.  */
+
+static void
+ftrace_debug (struct btrace_func *bfun, const char *prefix)
+{
+  DEBUG_FTRACE ("%s: fun = %s, file = %s, lines = [%d; %d], insn = [%u; %u]",
+		prefix, ftrace_print_function_name (bfun),
+		ftrace_print_filename (bfun), bfun->lbegin, bfun->lend,
+		bfun->ibegin, bfun->iend);
+}
+
+/* Initialize a recorded function segment.  */
+
+static void
+ftrace_init_func (struct btrace_func *bfun, struct minimal_symbol *mfun,
+		  struct symbol *fun, unsigned int idx)
+{
+  bfun->msym = mfun;
+  bfun->sym = fun;
+  bfun->lbegin = INT_MAX;
+  bfun->lend = 0;
+  bfun->ibegin = idx;
+  bfun->iend = idx;
+}
+
+/* Check whether the function has changed.  */
+
+static int
+ftrace_function_switched (struct btrace_func *bfun,
+			  struct minimal_symbol *mfun, struct symbol *fun)
+{
+  struct minimal_symbol *msym;
+  struct symbol *sym;
+
+  /* The function changed if we did not have one before.  */
+  if (bfun == NULL)
+    return 1;
+
+  msym = bfun->msym;
+  sym = bfun->sym;
+
+  /* If the minimal symbol changed, we certainly switched functions.  */
+  if (mfun != NULL && msym != NULL
+      && strcmp (SYMBOL_LINKAGE_NAME (mfun), SYMBOL_LINKAGE_NAME (msym)) != 0)
+    return 1;
+
+  /* If the symbol changed, we certainly switched functions.  */
+  if (fun != NULL && sym != NULL)
+    {
+      const char *bfname, *fname;
+
+      /* Check the function name.  */
+      if (strcmp (SYMBOL_LINKAGE_NAME (fun), SYMBOL_LINKAGE_NAME (sym)) != 0)
+	return 1;
+
+      /* Check the location of those functions, as well.  */
+      bfname = symtab_to_fullname (sym->symtab);
+      fname = symtab_to_fullname (fun->symtab);
+      if (filename_cmp (fname, bfname) != 0)
+	return 1;
+    }
+
+  return 0;
+}
+
+/* Check if we should skip this file when generating the function call
+   history.  We would want to do that if, say, a macro that is defined
+   in another file is expanded in this function.  */
+
+static int
+ftrace_skip_file (struct btrace_func *bfun, const char *filename)
+{
+  struct symbol *sym;
+  const char *bfile;
+
+  sym = bfun->sym;
+
+  if (sym != NULL)
+    bfile = symtab_to_fullname (sym->symtab);
+  else
+    bfile = "";
+
+  if (filename == NULL)
+    filename = "";
+
+  return (filename_cmp (bfile, filename) != 0);
+}
+
+/* Compute the function trace from the instruction trace.  */
+
+static VEC (btrace_func_s) *
+compute_ftrace (VEC (btrace_inst_s) *itrace)
+{
+  VEC (btrace_func_s) *ftrace;
+  struct btrace_inst *binst;
+  struct btrace_func *bfun;
+  unsigned int idx;
+
+  DEBUG ("compute ftrace");
+
+  ftrace = NULL;
+  bfun = NULL;
+
+  for (idx = 0; VEC_iterate (btrace_inst_s, itrace, idx, binst); ++idx)
+    {
+      struct symtab_and_line sal;
+      struct minimal_symbol *mfun;
+      struct symbol *fun;
+      const char *filename;
+      CORE_ADDR pc;
+
+      pc = binst->pc;
+
+      /* Try to determine the function we're in.  We use both types of symbols
+	 to avoid surprises when we sometimes get a full symbol and sometimes
+	 only a minimal symbol.  */
+      fun = find_pc_function (pc);
+      mfun = lookup_minimal_symbol_by_pc (pc);
+
+      if (fun == NULL && mfun == NULL)
+	{
+	  DEBUG_FTRACE ("no symbol at %u, pc=%s", idx,
+			core_addr_to_string_nz (pc));
+	  continue;
+	}
+
+      /* If we're switching functions, we start over.  */
+      if (ftrace_function_switched (bfun, mfun, fun))
+	{
+	  bfun = VEC_safe_push (btrace_func_s, ftrace, NULL);
+
+	  ftrace_init_func (bfun, mfun, fun, idx);
+	  ftrace_debug (bfun, "init");
+	}
+
+      /* Update the instruction range.  */
+      bfun->iend = idx;
+      ftrace_debug (bfun, "update insns");
+
+      /* Let's see if we have source correlation, as well.  */
+      sal = find_pc_line (pc, 0);
+      if (sal.symtab == NULL || sal.line == 0)
+	{
+	  DEBUG_FTRACE ("no lines at %u, pc=%s", idx,
+			core_addr_to_string_nz (pc));
+	  continue;
+	}
+
+      /* Check if we switched files.  This could happen if, say, a macro that
+	 is defined in another file is expanded here.  */
+      filename = symtab_to_fullname (sal.symtab);
+      if (ftrace_skip_file (bfun, filename))
+	{
+	  DEBUG_FTRACE ("ignoring file at %u, pc=%s, file=%s", idx,
+			core_addr_to_string_nz (pc), filename);
+	  continue;
+	}
+
+      /* Update the line range.  */
+      bfun->lbegin = min (bfun->lbegin, sal.line);
+      bfun->lend = max (bfun->lend, sal.line);
+      ftrace_debug (bfun, "update lines");
+    }
+
+  return ftrace;
+}
+
+/* See btrace.h.  */
+
+void
+btrace_enable (struct thread_info *tp)
+{
+  if (tp->btrace.target != NULL)
+    return;
+
+  if (!target_supports_btrace ())
+    error (_("Target does not support branch tracing."));
+
+  DEBUG ("enable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
+
+  tp->btrace.target = target_enable_btrace (tp->ptid);
+}
+
+/* See btrace.h.  */
+
+void
+btrace_disable (struct thread_info *tp)
+{
+  struct btrace_thread_info *btp = &tp->btrace;
+  int errcode = 0;
+
+  if (btp->target == NULL)
+    return;
+
+  DEBUG ("disable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
+
+  target_disable_btrace (btp->target);
+  btp->target = NULL;
+
+  btrace_clear (tp);
+}
+
+/* See btrace.h.  */
+
+void
+btrace_teardown (struct thread_info *tp)
+{
+  struct btrace_thread_info *btp = &tp->btrace;
+  int errcode = 0;
+
+  if (btp->target == NULL)
+    return;
+
+  DEBUG ("teardown thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
+
+  target_teardown_btrace (btp->target);
+  btp->target = NULL;
+
+  btrace_clear (tp);
+}
+
+/* See btrace.h.  */
+
+void
+btrace_fetch (struct thread_info *tp)
+{
+  struct btrace_thread_info *btinfo;
+  VEC (btrace_block_s) *btrace;
+
+  DEBUG ("fetch thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
+
+  btinfo = &tp->btrace;
+  if (btinfo->target == NULL)
+    return;
+
+  btrace = target_read_btrace (btinfo->target, btrace_read_new);
+  if (VEC_empty (btrace_block_s, btrace))
+    return;
+
+  btrace_clear (tp);
+
+  btinfo->btrace = btrace;
+  btinfo->itrace = compute_itrace (btinfo->btrace);
+  btinfo->ftrace = compute_ftrace (btinfo->itrace);
+
+  /* Initialize branch trace iterators.  */
+  btrace_init_insn_iterator (btinfo);
+  btrace_init_func_iterator (btinfo);
+}
+
+/* See btrace.h.  */
+
+void
+btrace_clear (struct thread_info *tp)
+{
+  struct btrace_thread_info *btinfo;
+
+  DEBUG ("clear thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
+
+  btinfo = &tp->btrace;
+
+  VEC_free (btrace_block_s, btinfo->btrace);
+  VEC_free (btrace_inst_s, btinfo->itrace);
+  VEC_free (btrace_func_s, btinfo->ftrace);
+
+  btinfo->btrace = NULL;
+  btinfo->itrace = NULL;
+  btinfo->ftrace = NULL;
+}
+
+/* See btrace.h.  */
+
+void
+btrace_free_objfile (struct objfile *objfile)
+{
+  struct thread_info *tp;
+
+  DEBUG ("free objfile");
+
+  ALL_THREADS (tp)
+    btrace_clear (tp);
+}