Re: [PATCHv4 5/5] gdb: Don't store a thread-id for floating varobj

[Simon Marchi <simark at simark dot ca>]

On 2017-10-19 09:27 AM, Andrew Burgess wrote:
> When creating a varobj with -var-create a user can create either fixed
> varobj, or floating varobj.
> 
> A fixed varobj will always be evaluated within the thread/frame/block in
> which the varobj was created, if that thread/frame/block is no longer
> available then the varobj is considered out of scope.
> 
> A floating varobj will always be evaluated within the current
> thread/frame/block.
> 
> Despite never using them GDB was storing the thread/frame/block into a
> floating varobj, and the thread-id would then be displayed when GDB
> reported on the state of the varobj, this could confuse a user into
> thinking that the thread-id was relevant.
> 
> This commit prevents GDB storing the thread/frame/block onto floating
> varobj, and updates the few tests where this impacts the results.
> 
> gdb/ChangeLog:
> 
> 	* varobj.c (varobj_create): Don't set valid_block when creating a
> 	floating varobj.
> 
> gdb/testsuite/ChangeLog:
> 
> 	* gdb.python/py-mi.exp: Don't expect a thread-id for floating
> 	varobj.
> 	* gdb.mi/mi-var-create-rtti.exp: Likewise.
> ---
>  gdb/ChangeLog                               |  5 +++++
>  gdb/testsuite/ChangeLog                     |  6 ++++++
>  gdb/testsuite/gdb.mi/mi-var-create-rtti.exp |  2 +-
>  gdb/testsuite/gdb.python/py-mi.exp          | 12 ++++++------
>  gdb/varobj.c                                |  3 ++-
>  5 files changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/gdb/testsuite/gdb.mi/mi-var-create-rtti.exp b/gdb/testsuite/gdb.mi/mi-var-create-rtti.exp
> index afc9c248ae..85ead72e7b 100644
> --- a/gdb/testsuite/gdb.mi/mi-var-create-rtti.exp
> +++ b/gdb/testsuite/gdb.mi/mi-var-create-rtti.exp
> @@ -52,6 +52,6 @@ mi_gdb_test "-var-create sp1 * ((void*)\$sp)" \
>  	    "\\^done,name=\"sp1\",numchild=\"0\",value=\"$hex\",type=\"void \\*\",thread-id=\"$decimal\",has_more=\"0\"" \
>  	    "-var-create sp1 * \$sp"
>  mi_gdb_test "-var-create sp2 @ ((void*)\$sp)" \
> -	    "\\^done,name=\"sp2\",numchild=\"0\",value=\"$hex\",type=\"void \\*\",thread-id=\"$decimal\",has_more=\"0\"" \
> +	    "\\^done,name=\"sp2\",numchild=\"0\",value=\"$hex\",type=\"void \\*\",has_more=\"0\"" \
>  	    "-var-create sp2 @ \$sp"
>  gdb_exit
> diff --git a/gdb/testsuite/gdb.python/py-mi.exp b/gdb/testsuite/gdb.python/py-mi.exp
> index 736dc7a0d6..aa9a2f12a2 100644
> --- a/gdb/testsuite/gdb.python/py-mi.exp
> +++ b/gdb/testsuite/gdb.python/py-mi.exp
> @@ -101,7 +101,7 @@ mi_varobj_update_dynamic container "varobj update 1" {
>      type_changed false new_num_children 1 dynamic 1 has_more 0
>  } {
>  } {
> -    { name {container.\[0\]} exp {\[0\]} numchild 0 type int thread-id 1 }
> +    { name {container.\[0\]} exp {\[0\]} numchild 0 type int }
>  }
>  
>  mi_next "next over update 2"
> @@ -110,7 +110,7 @@ mi_varobj_update_dynamic container "varobj update 2" {
>      type_changed false new_num_children 2 dynamic 1 has_more 0
>  } {
>  } {
> -    { name {container.\[1\]} exp {\[1\]} numchild 0 type int thread-id 1 }
> +    { name {container.\[1\]} exp {\[1\]} numchild 0 type int }
>  }
>  
>  mi_gdb_test "-var-set-visualizer container None" \
> @@ -129,8 +129,8 @@ mi_varobj_update_dynamic container "varobj update after choosing default" {
>      type_changed false new_num_children 2 dynamic 1 has_more 0
>  } {
>  } {
> -    { name {container.\[0\]} exp {\[0\]} numchild 0 type int thread-id 1 }
> -    { name {container.\[1\]} exp {\[1\]} numchild 0 type int thread-id 1 }
> +    { name {container.\[0\]} exp {\[0\]} numchild 0 type int }
> +    { name {container.\[1\]} exp {\[1\]} numchild 0 type int }
>  }
>  
>  mi_gdb_test "-var-set-visualizer container ContainerPrinter" \
> @@ -142,8 +142,8 @@ mi_varobj_update_dynamic container \
>        type_changed false new_num_children 2 dynamic 1 has_more 0
>    } {
>    } {
> -      { name {container.\[0\]} exp {\[0\]} numchild 0 type int thread-id 1 }
> -      { name {container.\[1\]} exp {\[1\]} numchild 0 type int thread-id 1 }
> +      { name {container.\[0\]} exp {\[0\]} numchild 0 type int }
> +      { name {container.\[1\]} exp {\[1\]} numchild 0 type int }
>    }
>  
>  mi_list_varobj_children_range container 1 2 2 {
> diff --git a/gdb/varobj.c b/gdb/varobj.c
> index d8b927ef4f..ee555b39ac 100644
> --- a/gdb/varobj.c
> +++ b/gdb/varobj.c
> @@ -351,7 +351,8 @@ varobj_create (const char *objname,
>  	}
>  
>        var->format = variable_default_display (var);
> -      var->root->valid_block = innermost_block.block ();
> +      var->root->valid_block =
> +	var->root->floating ? NULL : innermost_block.block ();
>        var->name = expression;
>        /* For a root var, the name and the expr are the same.  */
>        var->path_expr = expression;
> 

This LGTM.

Simon