Revert "Don't merge types of resources"
This reverts commit f393b0e480, but leaves
the tests that were added. Added new test. These test are the so that,
if someone tries the same change I made, they will see the test that
they need to handle.
Don't run remove duplicates in -O and -Os
Romve duplicates was run to help reduce compile time when looking for
types in the type manager. I've run compile time test on three sets
of shaders, and the compile time does not seem to change.
It should be safe to remove it.
When doing reflection users care about the names of the variable, the
name of the type, and the name of the members. Remove duplicates breaks
this because it removes the names one of the types when merging.
To fix this we have to keep the different types around for each
resource. This commit adds code to remove duplicates to look for the
types uses to describe resources, and make sure they do not get merged.
However, allow merging of a type used in a resource with something not
used in a resource. Was done when the non resource type came second.
This could have a negative effect on compile time, but it was not
expected to be much.
Fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/1372.
The merging types we do not remove other information related to the
types. We simply leave it duplicated, and hope it is removed later.
This is what happens with decorations. They are removed in the next
phase of remove duplicates. However, for OpNames that is not the case.
We end up with two different names for the same id, which does not make
sense.
The solution is to remove the names and decorations for the type being
removed instead of rewriting them to refer to the other type.
Note that it is possible that if the first type does not have a name,
then the types will end up with no name. That is fine because the names
should not have any semantic significance anyway.
The was identified in issue #1372, but this does not fix that issue.
