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Re: [RFA] Type inheritance graph analysis & speculative devirtualization, part 4/7, ODR at LTO time

On 08/19/2013 10:01 AM, Jan Hubicka wrote:
+   /* All equivalent types, if more than one.  */
+   vec<tree, va_gc> *types;
+   /* Set of all equivalent types, if NON-NULL.  */
+   pointer_set_t * GTY((skip)) types_set;

Why do you need both a vector and a pointer set? Can't you drop the vector and use pointer_set_traverse for operating on each of the elements?

+ 			     "type %qD violate one definition rule  ",


+ 		    "the type of same name with different memory layout "
+ 		    "defined in other compilation unit");

Is there any way to identify which TUs the definitions come from?

I would adjust the wording to

"a type with the same name but different layout is defined in another translation unit"

+ 		    "the inconsistent type of same name with different bases"
+ 		    " (defined in other compilation unit)");

and "a type with the same name but different base classes is defined in another translation unit"

+   /* When assembler name of virtual table is available, it is
+      easy to compare types for equivalence.
+      FIXME: the code comparing type names consider all instantiations of the
+      same template to have same name.  This is because we have no access
+      to template parameters.  For types with no virtual method tables
+      we thus can return false positives.  At the moment we do not need
+      to compare types in other scenarios than devirtualization.  */

This FIXME doesn't seem to apply to the case where we're comparing the vtable mangled names, so it should move later in the function.

OK with the diagnostic/comment issues fixed.

BTW, if anything asks for the DECL_ASSEMBLER_NAME of the TYPE_NAME, it will get an ODR-unique mangled name for the type. But we don't currently set that during normal compilation because it isn't used in mangling of actual symbols.


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