gdb: New API for tracking innermost block

This commit is preparation for a later change, at this point there
should be no user visible change.

We currently maintain a global innermost_block which tracks the most
inner block encountered when parsing an expression.

This commit wraps the innermost_block into a new class, and switches all
direct accesses to the variable to use the class API.

gdb/ChangeLog:

	* ada-exp.y (write_var_from_sym): Switch to innermost_block API.
	* ada-lang.c (resolve_subexp): Likewise.
	* breakpoint.c (set_breakpoint_condition) Likewise.
	(watch_command_1) Likewise.
	* c-exp.y (variable): Likewise.
	* d-exp.y (PrimaryExpression): Likewise.
	* f-exp.y (variable): Likewise.
	* go-exp.y (variable): Likewise.
	* m2-exp.y (variable): Likewise.
	* objfiles.c (objfile::~objfile): Likewise.
	* p-exp.y (variable): Likewise.
	* parse.c (innermost_block): Change type.
	* parser-defs.h (class innermost_block_tracker): New.
	(innermost_block): Change to innermost_block_tracker.
	* printcmd.c (display_command): Switch to innermost_block API.
	(do_one_display): Likewise.
	* rust-exp.y (do_one_display): Likewise.
	* symfile.c (clear_symtab_users): Likewise.
	* varobj.c (varobj_create): Switch to innermost_block API, replace
	use of innermost_block with block stored on varobj object.

1 files changed, 3 insertions, 3 deletions

diff --git a/gdb/varobj.c b/gdb/varobj.c
index 701ef66..20dd09b 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -311,7 +311,7 @@ varobj_create (const char *objname,
 	}
 
       p = expression;
-      innermost_block = NULL;
+      innermost_block.reset ();
       /* Wrap the call to parse expression, so we can 
          return a sensible error.  */
       TRY
@@ -336,7 +336,7 @@ varobj_create (const char *objname,
 	}
 
       var->format = variable_default_display (var.get ());
-      var->root->valid_block = innermost_block;
+      var->root->valid_block = innermost_block.block ();
       var->name = expression;
       /* For a root var, the name and the expr are the same.  */
       var->path_expr = expression;
@@ -345,7 +345,7 @@ varobj_create (const char *objname,
          we must select the appropriate frame before parsing
          the expression, otherwise the value will not be current.
          Since select_frame is so benign, just call it for all cases.  */
-      if (innermost_block)
+      if (var->root->valid_block)
 	{
 	  /* User could specify explicit FRAME-ADDR which was not found but
 	     EXPRESSION is frame specific and we would not be able to evaluate