[Mesa-dev] [PATCH 0/5] glsl: Clean up linker error checking.

[Paul Berry]

I recently discovered a bug in my geometry shader branch wherein we
were responding to certain kinds of link errors by calling
linker_error(), but the program was still linking successfully.  The
root cause turned out to be that during the first half of the
execution of link_shaders(), it was not sufficient to call
linker_error()--the code had to also tell link_shaders() (through
boolean return values) that the link had failed.  During the second
half link_shaders(), calling linker_error() was sufficient.

This patch series cleans things up so that calling linker_error() is
always sufficient to make the link fail, regardless of where execution
is in link_shaders().  The cleanup happens in patch 3/5.

In the process of making this fix, I also discovered one case where we
were flagging the link error by returning false to link_shaders(), but
we weren't calling linker_error().  As a result, the link would fail
(as it should) but there would be no error message in the log.  That
is fixed in patch 2/5.

Patch 1/5 removes some dead code which would have otherwise made the
clean-up harder to follow.  Patch 4/5 improves an error message that
was previously vague because we were calling linker_error() from a
point where we didn't have much information.  Finally, patch 5/5
removes some redundant code.

[PATCH 1/5] glsl: Remove bogus check on return value of link_uniform_blocks().
[PATCH 2/5] glsl: Add error message for intrastage interface block mismatch.
[PATCH 3/5] glsl: Use a consistent technique for tracking link success/failure.
[PATCH 4/5] glsl: Improve error message for interstage interface block mismatch.
[PATCH 5/5] glsl: Remove redundant writes to prog->LinkStatus