=================================================================^M
^[[1m^[[31m==12975==ERROR: AddressSanitizer: alloc-dealloc-mismatch (malloc vs operator delete) on 0x603000085e40^M
^[[1m^[[0m    #0 0x2b8ce74d15d7 in operator delete(void*) (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x555d7)^M
    #1 0xc13d3c in update_dynamic_varobj_children /home/yao/SourceCode/gnu/gdb/git/gdb/varobj.c:786^M
    #2 0xc1425f in varobj_get_num_children(varobj*) /home/yao/SourceCode/gnu/gdb/git/gdb/varobj.c:846^M
    #3 0x59ffeb in print_varobj /home/yao/SourceCode/gnu/gdb/git/gdb/mi/mi-cmd-var.c:61^M
    #4 0x5a0689 in mi_cmd_var_create(char*, char**, int) /home/yao/SourceCode/gnu/gdb/git/gdb/mi/mi-cmd-var.c:145^M
    #5 0x5b5ac9 in mi_cmd_execute /home/yao/SourceCode/gnu/gdb/git/gdb/mi/mi-main.c:2295^M
    #6 0x5b3de0 in captured_mi_execute_command /home/yao/SourceCode/gnu/gdb/git/gdb/mi/mi-main.c:1997^M
.....
^M
^[[1m^[[32m0x603000085e40 is located 0 bytes inside of 32-byte region [0x603000085e40,0x603000085e60)^M
^[[1m^[[0m^[[1m^[[35mallocated by thread T0 here:^[[1m^[[0m^M
    #0 0x2b8ce74d0862 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x54862)^M
    #1 0x80df7f in xmalloc /home/yao/SourceCode/gnu/gdb/git/gdb/common/common-utils.c:43^M
    #2 0x6364ec in py_varobj_iter_new /home/yao/SourceCode/gnu/gdb/git/gdb/python/py-varobj.c:154^M
    #3 0x636710 in py_varobj_get_iterator(varobj*, _object*) /home/yao/SourceCode/gnu/gdb/git/gdb/python/py-varobj.c:188^M
    #4 0xc13580 in varobj_get_iterator /home/yao/SourceCode/gnu/gdb/git/gdb/varobj.c:712^M
    #5 0xc138fa in update_dynamic_varobj_children /home/yao/SourceCode/gnu/gdb/git/gdb/varobj.c:750^M
    #6 0xc1425f in varobj_get_num_children(varobj*) /home/yao/SourceCode/gnu/gdb/git/gdb/varobj.c:846^M

reverting the change above fixes the error.  We can also C++-fy
varobj_iter, but I'd like to do in another patch.  How is the patch below?

>  	}				       \
>      } while (0)

> diff --git a/gdb/varobj.h b/gdb/varobj.h
> index 6b9a71f..7f4aad2 100644
> --- a/gdb/varobj.h
> +++ b/gdb/varobj.h
> @@ -86,22 +86,22 @@ struct varobj_dynamic;
>  
>  /* Every variable in the system has a structure of this type defined
>     for it.  This structure holds all information necessary to manipulate
> -   a particular object variable.  Members which must be freed are noted.  */
> +   a particular object variable.  */
>  struct varobj
>  {
> -  /* Alloc'd name of the variable for this object.  If this variable is a
> +  /* Name of the variable for this object.  If this variable is a
>       child, then this name will be the child's source name.
>       (bar, not foo.bar).  */
>    /* NOTE: This is the "expression".  */
> -  char *name;
> +  std::string name;
>  
> -  /* Alloc'd expression for this child.  Can be used to create a
> -     root variable corresponding to this child.  */
> -  char *path_expr;
> +  /* Expression for this child.  Can be used to create a root variable
> +     corresponding to this child.  */
> +  std::string path_expr;
>  
> -  /* The alloc'd name for this variable's object.  This is here for
> +  /* The name for this variable's object.  This is here for
>       convenience when constructing this object's children.  */
> -  char *obj_name;
> +  std::string obj_name;
>  
>    /* Index of this variable in its parent or -1.  */
>    int index;
> @@ -137,7 +137,7 @@ struct varobj
>    int updated;
>  
>    /* Last print value.  */
> -  char *print_value;
> +  std::string print_value;
>  
>    /* Is this variable frozen.  Frozen variables are never implicitly
>       updated by -var-update * 
> @@ -170,18 +170,15 @@ struct lang_varobj_ops
>    /* The number of children of PARENT.  */
>    int (*number_of_children) (const struct varobj *parent);
>  
> -  /* The name (expression) of a root varobj.  The returned value must be freed
> -     by the caller.  */
> -  char *(*name_of_variable) (const struct varobj *parent);
> +  /* The name (expression) of a root varobj.  */
> +  std::string (*name_of_variable) (const struct varobj *parent);
>  
> -  /* The name of the INDEX'th child of PARENT.  The returned value must be
> -     freed by the caller.  */
> -  char *(*name_of_child) (const struct varobj *parent, int index);
> +  /* The name of the INDEX'th child of PARENT.  */
> +  std::string (*name_of_child) (const struct varobj *parent, int index);
>  
>    /* Returns the rooted expression of CHILD, which is a variable
> -     obtain that has some parent.  The returned value must be freed by the
> -     caller.  */
> -  char *(*path_expr_of_child) (const struct varobj *child);
> +     obtain that has some parent.  */
> +  std::string (*path_expr_of_child) (const struct varobj *child);
>  
>    /* The ``struct value *'' of the INDEX'th child of PARENT.  */
>    struct value *(*value_of_child) (const struct varobj *parent, int index);
> @@ -189,10 +186,9 @@ struct lang_varobj_ops
>    /* The type of the INDEX'th child of PARENT.  */
>    struct type *(*type_of_child) (const struct varobj *parent, int index);
>  
> -  /* The current value of VAR.  The returned value must be freed by the
> -     caller.  */
> -  char *(*value_of_variable) (const struct varobj *var,
> -			      enum varobj_display_formats format);
> +  /* The current value of VAR.  */
> +  std::string (*value_of_variable) (const struct varobj *var,
> +				    enum varobj_display_formats format);
>  
>    /* Return non-zero if changes in value of VAR must be detected and
>       reported by -var-update.  Return zero if -var-update should never

-- 
Yao (é½å°§)
From 71dc64a061cfb1ec57b753e495c02665827c7a01 Mon Sep 17 00:00:00 2001
From: Yao Qi <yao.qi@linaro.org>
Date: Thu, 23 Feb 2017 09:29:48 +0000
Subject: [PATCH] Use xfree rather than delete for varobj_iter

ASAN reports an error,

-var-create container @ c^M
=================================================================^M
^[[1m^[[31m==21639==ERROR: AddressSanitizer: alloc-dealloc-mismatch (malloc vs operator delete) on 0x6030000805c0^M
^[[1m^[[0m    #0 0x7f2449b01b2a in operator delete(void*) (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x99b2a)^M
    #1 0xbb601d in update_dynamic_varobj_children ../../binutils-gdb/gdb/varobj.c:794^M
    #2 0xbb6556 in varobj_get_num_children(varobj*) ../../binutils-gdb/gdb/varobj.c:854^M
    #3 0x580cb4 in print_varobj ../../binutils-gdb/gdb/mi/mi-cmd-var.c:61^M
    #4 0x58138b in mi_cmd_var_create(char*, char**, int) ../../binutils-gdb/gdb/mi/mi-cmd-var.c:145^M
    #5 0x5967ce in mi_cmd_execute ../../binutils-gdb/gdb/mi/mi-main.c:2301^M
    #6 0x594b05 in captured_mi_execute_command ../../binutils-gdb/gdb/mi/mi-main.c:2001
....
^M
^[[1m^[[32m0x6030000805c0 is located 0 bytes inside of 32-byte region [0x6030000805c0,0x6030000805e0)^M
^[[1m^[[0m^[[1m^[[35mallocated by thread T0 here:^[[1m^[[0m^M
    #0 0x7f2449b00602 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x98602)^M
    #1 0x7d1596 in xmalloc ../../binutils-gdb/gdb/common/common-utils.c:43^M
    #2 0x604176 in py_varobj_iter_new ../../binutils-gdb/gdb/python/py-varobj.c:159^M
    #3 0x6042da in py_varobj_get_iterator(varobj*, _object*) ../../binutils-gdb/gdb/python/py-varobj.c:198^M
    #4 0xbb5806 in varobj_get_iterator ../../binutils-gdb/gdb/varobj.c:720^M
    #5 0xbb5b9b in update_dynamic_varobj_children ../../binutils-gdb/gdb/varobj.c:758^M

gdb:

2017-02-23  Yao Qi  <yao.qi@linaro.org>

	* varobj-iter.h (varobj_iter_delete): Call xfree instead of
	delete.

diff --git a/gdb/varobj-iter.h b/gdb/varobj-iter.h
index 34182e0..7eed4f1 100644
--- a/gdb/varobj-iter.h
+++ b/gdb/varobj-iter.h
@@ -67,6 +67,6 @@ struct varobj_iter_ops
       if ((ITER) != NULL)		       \
 	{				       \
 	  (ITER)->ops->dtor (ITER);	       \
-	  delete (ITER);		       \
+	  xfree (ITER);		       \
 	}				       \
     } while (0)
