[PATCH v2 13/31] Introduce read_var_value overload

[Tom Tromey <tom@tromey.com>]

This adds an overload of read_var_value that accepts a block_symbol.
The next batch of patches concern rewriting gdb to use this overload,
in the end allowing us to remove a use of value_address.
---
 gdb/compile/compile-c-symbols.c     |  2 +-
 gdb/compile/compile-cplus-symbols.c |  2 +-
 gdb/findvar.c                       | 12 ++++++++++++
 gdb/infrun.c                        |  2 +-
 gdb/valops.c                        | 26 ++++++++++++--------------
 gdb/value.h                         |  3 +++
 6 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/gdb/compile/compile-c-symbols.c b/gdb/compile/compile-c-symbols.c
index 2d49ead249e..40578bf36f4 100644
--- a/gdb/compile/compile-c-symbols.c
+++ b/gdb/compile/compile-c-symbols.c
@@ -155,7 +155,7 @@ convert_one_symbol (compile_c_instance *context,
 			 sym.symbol->print_name ());
 	      }
 
-	    val = read_var_value (sym.symbol, sym.block, frame);
+	    val = read_var_value (sym, frame);
 	    if (val->lval () != lval_memory)
 	      error (_("Symbol \"%s\" cannot be used for compilation "
 		       "evaluation as its address has not been found."),
diff --git a/gdb/compile/compile-cplus-symbols.c b/gdb/compile/compile-cplus-symbols.c
index dec0260bf7a..1288225f08e 100644
--- a/gdb/compile/compile-cplus-symbols.c
+++ b/gdb/compile/compile-cplus-symbols.c
@@ -151,7 +151,7 @@ convert_one_symbol (compile_cplus_instance *instance,
 			 sym.symbol->print_name ());
 	      }
 
-	    val = read_var_value (sym.symbol, sym.block, frame);
+	    val = read_var_value (sym, frame);
 	    if (val->lval () != lval_memory)
 	      error (_("Symbol \"%s\" cannot be used for compilation "
 		       "evaluation as its address has not been found."),
diff --git a/gdb/findvar.c b/gdb/findvar.c
index 4e992ecdcc7..909dca65532 100644
--- a/gdb/findvar.c
+++ b/gdb/findvar.c
@@ -794,6 +794,18 @@ read_var_value (struct symbol *var, const struct block *var_block,
   return lang->read_var_value (var, var_block, frame);
 }
 
+/* Calls VAR's language read_var_value hook with the given arguments.  */
+
+struct value *
+read_var_value (block_symbol var, frame_info_ptr frame)
+{
+  const struct language_defn *lang = language_def (var.symbol->language ());
+
+  gdb_assert (lang != NULL);
+
+  return lang->read_var_value (var.symbol, var.block, frame);
+}
+
 /* Install default attributes for register values.  */
 
 struct value *
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 4fde96800fb..a7cb02c958e 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -8311,7 +8311,7 @@ insert_exception_resume_breakpoint (struct thread_info *tp,
 
       vsym = lookup_symbol_search_name (sym->search_name (),
 					b, VAR_DOMAIN);
-      value = read_var_value (vsym.symbol, vsym.block, frame);
+      value = read_var_value (vsym, frame);
       /* If the value was optimized out, revert to the old behavior.  */
       if (! value->optimized_out ())
 	{
diff --git a/gdb/valops.c b/gdb/valops.c
index 70851cd40b4..b7ed458a649 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -3711,17 +3711,16 @@ value_struct_elt_for_reference (struct type *domain, int offset,
 
 	  if (TYPE_FN_FIELD_STATIC_P (f, j))
 	    {
-	      struct symbol *s = 
-		lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
-			       0, VAR_DOMAIN, 0).symbol;
+	      block_symbol s = lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
+					      0, VAR_DOMAIN, 0);
 
-	      if (s == NULL)
-		return NULL;
+	      if (s.symbol == nullptr)
+		return nullptr;
 
 	      if (want_address)
-		return value_addr (read_var_value (s, 0, 0));
+		return value_addr (read_var_value (s, 0));
 	      else
-		return read_var_value (s, 0, 0);
+		return read_var_value (s, 0);
 	    }
 
 	  if (TYPE_FN_FIELD_VIRTUAL_P (f, j))
@@ -3742,14 +3741,13 @@ value_struct_elt_for_reference (struct type *domain, int offset,
 	    }
 	  else
 	    {
-	      struct symbol *s = 
-		lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
-			       0, VAR_DOMAIN, 0).symbol;
+	      block_symbol s = lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
+					      0, VAR_DOMAIN, 0);
 
-	      if (s == NULL)
-		return NULL;
+	      if (s.symbol == nullptr)
+		return nullptr;
 
-	      struct value *v = read_var_value (s, 0, 0);
+	      struct value *v = read_var_value (s, 0);
 	      if (!want_address)
 		result = v;
 	      else
@@ -4000,7 +3998,7 @@ value_of_this (const struct language_defn *lang)
     error (_("current stack frame does not contain a variable named `%s'"),
 	   lang->name_of_this ());
 
-  return read_var_value (sym.symbol, sym.block, frame);
+  return read_var_value (sym, frame);
 }
 
 /* Return the value of the local variable, if one exists.  Return NULL
diff --git a/gdb/value.h b/gdb/value.h
index e4912717684..b683cbf5f90 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -1140,6 +1140,9 @@ extern struct value *read_var_value (struct symbol *var,
 				     const struct block *var_block,
 				     frame_info_ptr frame);
 
+extern struct value *read_var_value (block_symbol var,
+				     frame_info_ptr frame);
+
 extern struct value *allocate_repeat_value (struct type *type, int count);
 
 extern struct value *value_mark (void);

-- 
2.41.0