[Mesa-dev] [PATCH] glsl: Remove unused ast copy constructors.

[Matt Turner]

On Fri, Nov 21, 2014 at 10:52 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Fri, Nov 21, 2014 at 1:47 PM, Matt Turner <mattst88 at gmail.com> wrote:
>> These were added in commits a760c738 and 43757135 to be used in
>> implementing C-style aggregate initializers (commit 1b0d6aef). Paul
>> rewrote that code in commit 0da1a2cc to use GLSL types, rather than
>> AST types, leaving these copy constructors unused.
>>
>> Tested by making them private and providing no definition.
>> ---
>>  src/glsl/ast.h | 29 -----------------------------
>>  1 file changed, 29 deletions(-)
>>
>> diff --git a/src/glsl/ast.h b/src/glsl/ast.h
>> index 15bf086..6995ae8 100644
>> --- a/src/glsl/ast.h
>> +++ b/src/glsl/ast.h
>> @@ -640,19 +640,6 @@ class ast_declarator_list;
>>
>>  class ast_struct_specifier : public ast_node {
>>  public:
>> -   /**
>> -    * \brief Make a shallow copy of an ast_struct_specifier.
>> -    *
>> -    * Use only if the objects are allocated from the same context and will not
>> -    * be modified. Zeros the inherited ast_node's fields.
>> -    */
>> -   ast_struct_specifier(const ast_struct_specifier& that):
>> -      ast_node(), name(that.name), declarations(that.declarations),
>> -      is_declaration(that.is_declaration)
>> -   {
>> -      /* empty */
>> -   }
>> -
>
> Not sure what the style in mesa is, but IME, C++ copy constructors can
> spring up on you at fairly unexpected times, esp implicit ones. It
> will also happily generate a default one for you, which is almost
> never what you want. The style I've usually seen is to create private
> copy constructors without definition to catch such situations.

That's true, but they were added for usage in one place and that one
place has been removed, and we've never needed it anywhere else.