Don't assume break/continue inside a TRY block works

In C++, this:

	try
	  {
	    break;
	  }
	catch (..)
	  {}

is invalid.  However, because our TRY/CATCH macros support it in C,
the C++ version of those macros support it too.  To catch such
assumptions, this adds a (disabled) hack that maps TRY/CATCH to raw
C++ try/catch.  Then it goes through all instances that building on
x86_64 GNU/Linux trips on, fixing them.

This isn't strictly necessary yet, but I think it's nicer to try to
keep the tree in a state where it's easier to eliminate the TRY/CATCH
macros.

gdb/ChangeLog:
2015-10-29  Pedro Alves  <palves@redhat.com>

	* dwarf2-frame-tailcall.c (dwarf2_tailcall_sniffer_first): Don't
	assume that "break" breaks out of a TRY/CATCH.
	* python/py-framefilter.c (py_print_single_arg): Don't assume
	"continue" breaks out of a TRY/CATCH.
	* python/py-value.c (valpy_binop_throw): New function, factored
	out from ...
	(valpy_binop): ... this.
	(valpy_richcompare_throw): New function, factored
	out from ...
	(valpy_richcompare): ... this.
	* solib.c (solib_read_symbols): Don't assume "break" breaks out
	of a TRY/CATCH.
	* common/common-exceptions.h [USE_RAW_CXX_TRY]
	<TRY/CATCH/END_CATCH>: Define as 1-1 wrappers around try/catch.

6 files changed, 261 insertions, 194 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 7209666..27712b3 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,20 @@
+2015-10-29  Pedro Alves  <palves@redhat.com>
+
+	* dwarf2-frame-tailcall.c (dwarf2_tailcall_sniffer_first): Don't
+	assume that "break" breaks out of a TRY/CATCH.
+	* python/py-framefilter.c (py_print_single_arg): Don't assume
+	"continue" breaks out of a TRY/CATCH.
+	* python/py-value.c (valpy_binop_throw): New function, factored
+	out from ...
+	(valpy_binop): ... this.
+	(valpy_richcompare_throw): New function, factored
+	out from ...
+	(valpy_richcompare): ... this.
+	* solib.c (solib_read_symbols): Don't assume "break" breaks out
+	of a TRY/CATCH.
+	* common/common-exceptions.h [USE_RAW_CXX_TRY]
+	<TRY/CATCH/END_CATCH>: Define as 1-1 wrappers around try/catch.
+
 2015-10-28  Simon Dardis  <Simon.Dardis@imgtec.com>
 
 	* mips-linux-tdep.c (mips_linux_in_dynsym_stub): Recognise 'or'
diff --git a/gdb/common/common-exceptions.h b/gdb/common/common-exceptions.h
index 2e6a6d9..51795b1 100644
--- a/gdb/common/common-exceptions.h
+++ b/gdb/common/common-exceptions.h
@@ -195,6 +195,14 @@ struct exception_try_scope
   void *saved_state;
 };
 
+/* Define this to build with TRY/CATCH mapped directly to raw
+   try/catch.  GDB won't work correctly, but building that way catches
+   code tryin to break/continue out of the try block, along with
+   spurious code between the TRY and the CATCH block.  */
+//#define USE_RAW_CXX_TRY
+
+#ifndef USE_RAW_CXX_TRY
+
 /* We still need to wrap TRY/CATCH in C++ so that cleanups and C++
    exceptions can coexist.  The TRY blocked is wrapped in a
    do/while(0) so that break/continue within the block works the same
@@ -216,6 +224,14 @@ struct exception_try_scope
   {						\
     exception_rethrow ();			\
   }
+#else
+
+#define TRY try
+#define CATCH(EXCEPTION, MASK) \
+  catch (struct gdb_exception ## _ ## MASK &EXCEPTION)
+#define END_CATCH
+
+#endif
 
 /* The exception types client code may catch.  They're just shims
    around gdb_exception that add nothing but type info.  Which is used
diff --git a/gdb/dwarf2-frame-tailcall.c b/gdb/dwarf2-frame-tailcall.c
index 952bc14..613cc34 100644
--- a/gdb/dwarf2-frame-tailcall.c
+++ b/gdb/dwarf2-frame-tailcall.c
@@ -386,13 +386,15 @@ dwarf2_tailcall_sniffer_first (struct frame_info *this_frame,
       /* call_site_find_chain can throw an exception.  */
       chain = call_site_find_chain (prev_gdbarch, prev_pc, this_pc);
 
-      if (entry_cfa_sp_offsetp == NULL)
-	break;
-      sp_regnum = gdbarch_sp_regnum (prev_gdbarch);
-      if (sp_regnum == -1)
-	break;
-      prev_sp = frame_unwind_register_unsigned (this_frame, sp_regnum);
-      prev_sp_p = 1;
+      if (entry_cfa_sp_offsetp != NULL)
+	{
+	  sp_regnum = gdbarch_sp_regnum (prev_gdbarch);
+	  if (sp_regnum != -1)
+	    {
+	      prev_sp = frame_unwind_register_unsigned (this_frame, sp_regnum);
+	      prev_sp_p = 1;
+	    }
+	}
     }
   CATCH (except, RETURN_MASK_ERROR)
     {
diff --git a/gdb/python/py-framefilter.c b/gdb/python/py-framefilter.c
index ac97723..0f8dc62 100644
--- a/gdb/python/py-framefilter.c
+++ b/gdb/python/py-framefilter.c
@@ -448,37 +448,39 @@ py_print_single_arg (struct ui_out *out,
 	    {
 	      retval = EXT_LANG_BT_ERROR;
 	      do_cleanups (cleanups);
-	      continue;
 	    }
 	}
 
-      if (val != NULL)
-	annotate_arg_value (value_type (val));
-
-      /* If the output is to the CLI, and the user option "set print
-	 frame-arguments" is set to none, just output "...".  */
-      if (! ui_out_is_mi_like_p (out) && args_type == NO_VALUES)
-	ui_out_field_string (out, "value", "...");
-      else
+      if (retval != EXT_LANG_BT_ERROR)
 	{
-	  /* Otherwise, print the value for both MI and the CLI, except
-	     for the case of MI_PRINT_NO_VALUES.  */
-	  if (args_type != NO_VALUES)
+	  if (val != NULL)
+	    annotate_arg_value (value_type (val));
+
+	  /* If the output is to the CLI, and the user option "set print
+	     frame-arguments" is set to none, just output "...".  */
+	  if (! ui_out_is_mi_like_p (out) && args_type == NO_VALUES)
+	    ui_out_field_string (out, "value", "...");
+	  else
 	    {
-	      if (val == NULL)
+	      /* Otherwise, print the value for both MI and the CLI, except
+		 for the case of MI_PRINT_NO_VALUES.  */
+	      if (args_type != NO_VALUES)
 		{
-		  gdb_assert (fa != NULL && fa->error != NULL);
-		  ui_out_field_fmt (out, "value",
-				    _("<error reading variable: %s>"),
-				    fa->error);
+		  if (val == NULL)
+		    {
+		      gdb_assert (fa != NULL && fa->error != NULL);
+		      ui_out_field_fmt (out, "value",
+					_("<error reading variable: %s>"),
+					fa->error);
+		    }
+		  else if (py_print_value (out, val, opts, 0, args_type, language)
+			   == EXT_LANG_BT_ERROR)
+		    retval = EXT_LANG_BT_ERROR;
 		}
-	      else if (py_print_value (out, val, opts, 0, args_type, language)
-		       == EXT_LANG_BT_ERROR)
-		retval = EXT_LANG_BT_ERROR;
 	    }
-	}
 
-      do_cleanups (cleanups);
+	  do_cleanups (cleanups);
+	}
     }
   CATCH (except, RETURN_MASK_ERROR)
     {
diff --git a/gdb/python/py-value.c b/gdb/python/py-value.c
index ac6b224..140aaf5 100644
--- a/gdb/python/py-value.c
+++ b/gdb/python/py-value.c
@@ -1018,133 +1018,147 @@ enum valpy_opcode
 #define STRIP_REFERENCE(TYPE) \
   ((TYPE_CODE (TYPE) == TYPE_CODE_REF) ? (TYPE_TARGET_TYPE (TYPE)) : (TYPE))
 
-/* Returns a value object which is the result of applying the operation
-   specified by OPCODE to the given arguments.  Returns NULL on error, with
-   a python exception set.  */
+/* Helper for valpy_binop.  Returns a value object which is the result
+   of applying the operation specified by OPCODE to the given
+   arguments.  Throws a GDB exception on error.  */
+
 static PyObject *
-valpy_binop (enum valpy_opcode opcode, PyObject *self, PyObject *other)
+valpy_binop_throw (enum valpy_opcode opcode, PyObject *self, PyObject *other)
 {
   PyObject *result = NULL;
 
-  TRY
+  struct value *arg1, *arg2;
+  struct cleanup *cleanup = make_cleanup_value_free_to_mark (value_mark ());
+  struct value *res_val = NULL;
+  enum exp_opcode op = OP_NULL;
+  int handled = 0;
+
+  /* If the gdb.Value object is the second operand, then it will be
+     passed to us as the OTHER argument, and SELF will be an entirely
+     different kind of object, altogether.  Because of this, we can't
+     assume self is a gdb.Value object and need to convert it from
+     python as well.  */
+  arg1 = convert_value_from_python (self);
+  if (arg1 == NULL)
     {
-      struct value *arg1, *arg2;
-      struct cleanup *cleanup = make_cleanup_value_free_to_mark (value_mark ());
-      struct value *res_val = NULL;
-      enum exp_opcode op = OP_NULL;
-      int handled = 0;
-
-      /* If the gdb.Value object is the second operand, then it will be passed
-	 to us as the OTHER argument, and SELF will be an entirely different
-	 kind of object, altogether.  Because of this, we can't assume self is
-	 a gdb.Value object and need to convert it from python as well.  */
-      arg1 = convert_value_from_python (self);
-      if (arg1 == NULL)
-	{
-	  do_cleanups (cleanup);
-	  break;
-	}
+      do_cleanups (cleanup);
+      return NULL;
+    }
 
-      arg2 = convert_value_from_python (other);
-      if (arg2 == NULL)
-	{
-	  do_cleanups (cleanup);
-	  break;
-	}
+  arg2 = convert_value_from_python (other);
+  if (arg2 == NULL)
+    {
+      do_cleanups (cleanup);
+      return NULL;
+    }
 
-      switch (opcode)
-	{
-	case VALPY_ADD:
+  switch (opcode)
+    {
+    case VALPY_ADD:
+      {
+	struct type *ltype = value_type (arg1);
+	struct type *rtype = value_type (arg2);
+
+	ltype = check_typedef (ltype);
+	ltype = STRIP_REFERENCE (ltype);
+	rtype = check_typedef (rtype);
+	rtype = STRIP_REFERENCE (rtype);
+
+	handled = 1;
+	if (TYPE_CODE (ltype) == TYPE_CODE_PTR
+	    && is_integral_type (rtype))
+	  res_val = value_ptradd (arg1, value_as_long (arg2));
+	else if (TYPE_CODE (rtype) == TYPE_CODE_PTR
+		 && is_integral_type (ltype))
+	  res_val = value_ptradd (arg2, value_as_long (arg1));
+	else
 	  {
-	    struct type *ltype = value_type (arg1);
-	    struct type *rtype = value_type (arg2);
-
-	    ltype = check_typedef (ltype);
-	    ltype = STRIP_REFERENCE (ltype);
-	    rtype = check_typedef (rtype);
-	    rtype = STRIP_REFERENCE (rtype);
-
-	    handled = 1;
-	    if (TYPE_CODE (ltype) == TYPE_CODE_PTR
-		&& is_integral_type (rtype))
-	      res_val = value_ptradd (arg1, value_as_long (arg2));
-	    else if (TYPE_CODE (rtype) == TYPE_CODE_PTR
-		     && is_integral_type (ltype))
-	      res_val = value_ptradd (arg2, value_as_long (arg1));
-	    else
-	      {
-		handled = 0;
-		op = BINOP_ADD;
-	      }
+	    handled = 0;
+	    op = BINOP_ADD;
 	  }
-	  break;
-	case VALPY_SUB:
+      }
+      break;
+    case VALPY_SUB:
+      {
+	struct type *ltype = value_type (arg1);
+	struct type *rtype = value_type (arg2);
+
+	ltype = check_typedef (ltype);
+	ltype = STRIP_REFERENCE (ltype);
+	rtype = check_typedef (rtype);
+	rtype = STRIP_REFERENCE (rtype);
+
+	handled = 1;
+	if (TYPE_CODE (ltype) == TYPE_CODE_PTR
+	    && TYPE_CODE (rtype) == TYPE_CODE_PTR)
+	  /* A ptrdiff_t for the target would be preferable here.  */
+	  res_val = value_from_longest (builtin_type_pyint,
+					value_ptrdiff (arg1, arg2));
+	else if (TYPE_CODE (ltype) == TYPE_CODE_PTR
+		 && is_integral_type (rtype))
+	  res_val = value_ptradd (arg1, - value_as_long (arg2));
+	else
 	  {
-	    struct type *ltype = value_type (arg1);
-	    struct type *rtype = value_type (arg2);
-
-	    ltype = check_typedef (ltype);
-	    ltype = STRIP_REFERENCE (ltype);
-	    rtype = check_typedef (rtype);
-	    rtype = STRIP_REFERENCE (rtype);
-
-	    handled = 1;
-	    if (TYPE_CODE (ltype) == TYPE_CODE_PTR
-		&& TYPE_CODE (rtype) == TYPE_CODE_PTR)
-	      /* A ptrdiff_t for the target would be preferable here.  */
-	      res_val = value_from_longest (builtin_type_pyint,
-					    value_ptrdiff (arg1, arg2));
-	    else if (TYPE_CODE (ltype) == TYPE_CODE_PTR
-		     && is_integral_type (rtype))
-	      res_val = value_ptradd (arg1, - value_as_long (arg2));
-	    else
-	      {
-		handled = 0;
-		op = BINOP_SUB;
-	      }
+	    handled = 0;
+	    op = BINOP_SUB;
 	  }
-	  break;
-	case VALPY_MUL:
-	  op = BINOP_MUL;
-	  break;
-	case VALPY_DIV:
-	  op = BINOP_DIV;
-	  break;
-	case VALPY_REM:
-	  op = BINOP_REM;
-	  break;
-	case VALPY_POW:
-	  op = BINOP_EXP;
-	  break;
-	case VALPY_LSH:
-	  op = BINOP_LSH;
-	  break;
-	case VALPY_RSH:
-	  op = BINOP_RSH;
-	  break;
-	case VALPY_BITAND:
-	  op = BINOP_BITWISE_AND;
-	  break;
-	case VALPY_BITOR:
-	  op = BINOP_BITWISE_IOR;
-	  break;
-	case VALPY_BITXOR:
-	  op = BINOP_BITWISE_XOR;
-	  break;
-	}
+      }
+      break;
+    case VALPY_MUL:
+      op = BINOP_MUL;
+      break;
+    case VALPY_DIV:
+      op = BINOP_DIV;
+      break;
+    case VALPY_REM:
+      op = BINOP_REM;
+      break;
+    case VALPY_POW:
+      op = BINOP_EXP;
+      break;
+    case VALPY_LSH:
+      op = BINOP_LSH;
+      break;
+    case VALPY_RSH:
+      op = BINOP_RSH;
+      break;
+    case VALPY_BITAND:
+      op = BINOP_BITWISE_AND;
+      break;
+    case VALPY_BITOR:
+      op = BINOP_BITWISE_IOR;
+      break;
+    case VALPY_BITXOR:
+      op = BINOP_BITWISE_XOR;
+      break;
+    }
+
+  if (!handled)
+    {
+      if (binop_user_defined_p (op, arg1, arg2))
+	res_val = value_x_binop (arg1, arg2, op, OP_NULL, EVAL_NORMAL);
+      else
+	res_val = value_binop (arg1, arg2, op);
+    }
 
-      if (!handled)
-	{
-	  if (binop_user_defined_p (op, arg1, arg2))
-	    res_val = value_x_binop (arg1, arg2, op, OP_NULL, EVAL_NORMAL);
-	  else
-	    res_val = value_binop (arg1, arg2, op);
-	}
+  if (res_val)
+    result = value_to_value_object (res_val);
 
-      if (res_val)
-	result = value_to_value_object (res_val);
+  do_cleanups (cleanup);
+  return result;
+}
 
-      do_cleanups (cleanup);
+/* Returns a value object which is the result of applying the operation
+   specified by OPCODE to the given arguments.  Returns NULL on error, with
+   a python exception set.  */
+static PyObject *
+valpy_binop (enum valpy_opcode opcode, PyObject *self, PyObject *other)
+{
+  PyObject *result = NULL;
+
+  TRY
+    {
+      result = valpy_binop_throw (opcode, self, other);
     }
   CATCH (except, RETURN_MASK_ALL)
     {
@@ -1351,6 +1365,63 @@ valpy_xor (PyObject *self, PyObject *other)
   return valpy_binop (VALPY_BITXOR, self, other);
 }
 
+/* Helper for valpy_richcompare.  Implements comparison operations for
+   value objects.  Returns true/false on success.  Returns -1 with a
+   Python exception set if a Python error is detected.  Throws a GDB
+   exception on other errors (memory error, etc.).  */
+
+static int
+valpy_richcompare_throw (PyObject *self, PyObject *other, int op)
+{
+  int result;
+  struct value *value_other;
+  struct value *value_self;
+  struct value *mark = value_mark ();
+  struct cleanup *cleanup;
+
+  value_other = convert_value_from_python (other);
+  if (value_other == NULL)
+    return -1;
+
+  cleanup = make_cleanup_value_free_to_mark (mark);
+
+  value_self = ((value_object *) self)->value;
+
+  switch (op)
+    {
+    case Py_LT:
+      result = value_less (value_self, value_other);
+      break;
+    case Py_LE:
+      result = value_less (value_self, value_other)
+	|| value_equal (value_self, value_other);
+      break;
+    case Py_EQ:
+      result = value_equal (value_self, value_other);
+      break;
+    case Py_NE:
+      result = !value_equal (value_self, value_other);
+      break;
+    case Py_GT:
+      result = value_less (value_other, value_self);
+      break;
+    case Py_GE:
+      result = (value_less (value_other, value_self)
+		|| value_equal (value_self, value_other));
+      break;
+    default:
+      /* Can't happen.  */
+      PyErr_SetString (PyExc_NotImplementedError,
+		       _("Invalid operation on gdb.Value."));
+      result = -1;
+      break;
+    }
+
+  do_cleanups (cleanup);
+  return result;
+}
+
+
 /* Implements comparison operations for value objects.  Returns NULL on error,
    with a python exception set.  */
 static PyObject *
@@ -1379,48 +1450,7 @@ valpy_richcompare (PyObject *self, PyObject *other, int op)
 
   TRY
     {
-      struct value *value_other, *mark = value_mark ();
-      struct cleanup *cleanup;
-
-      value_other = convert_value_from_python (other);
-      if (value_other == NULL)
-	{
-	  result = -1;
-	  break;
-	}
-
-      cleanup = make_cleanup_value_free_to_mark (mark);
-
-      switch (op) {
-        case Py_LT:
-	  result = value_less (((value_object *) self)->value, value_other);
-	  break;
-	case Py_LE:
-	  result = value_less (((value_object *) self)->value, value_other)
-	    || value_equal (((value_object *) self)->value, value_other);
-	  break;
-	case Py_EQ:
-	  result = value_equal (((value_object *) self)->value, value_other);
-	  break;
-	case Py_NE:
-	  result = !value_equal (((value_object *) self)->value, value_other);
-	  break;
-        case Py_GT:
-	  result = value_less (value_other, ((value_object *) self)->value);
-	  break;
-	case Py_GE:
-	  result = value_less (value_other, ((value_object *) self)->value)
-	    || value_equal (((value_object *) self)->value, value_other);
-	  break;
-	default:
-	  /* Can't happen.  */
-	  PyErr_SetString (PyExc_NotImplementedError,
-			   _("Invalid operation on gdb.Value."));
-	  result = -1;
-	  break;
-      }
-
-      do_cleanups (cleanup);
+      result = valpy_richcompare_throw (self, other, op);
     }
   CATCH (except, RETURN_MASK_ALL)
     {
diff --git a/gdb/solib.c b/gdb/solib.c
index ca2c9ab..d715897 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -696,16 +696,16 @@ solib_read_symbols (struct so_list *so, int flags)
 		  && so->objfile->addr_low == so->addr_low)
 		break;
 	    }
-	  if (so->objfile != NULL)
-	    break;
-
-	  sap = build_section_addr_info_from_section_table (so->sections,
-							    so->sections_end);
-	  so->objfile = symbol_file_add_from_bfd (so->abfd, so->so_name,
-						  flags, sap, OBJF_SHARED,
-						  NULL);
-	  so->objfile->addr_low = so->addr_low;
-	  free_section_addr_info (sap);
+	  if (so->objfile == NULL)
+	    {
+	      sap = build_section_addr_info_from_section_table (so->sections,
+								so->sections_end);
+	      so->objfile = symbol_file_add_from_bfd (so->abfd, so->so_name,
+						      flags, sap, OBJF_SHARED,
+						      NULL);
+	      so->objfile->addr_low = so->addr_low;
+	      free_section_addr_info (sap);
+	    }
 
 	  so->symbols_loaded = 1;
 	}