Commit Graph

5 Commits

Author SHA1 Message Date
Alastair Donaldson
983b5b4fcc
spirv-fuzz: Use validator to check break/continue dominance conditions (#3089)
The passes that add dead breaks and continues suffer from the
challenge that a new control flow graph edge can change dominance
information, leading to the potenital for definitions to no longer
dominate their uses.  The attempt at guarding against this was known
to be incomplete.  This change calls on the SPIR-V validator to do the
necessary checking: in deciding whether adding such an edge would be
legitimate, we clone the module, add the edge, and use the validator
to check whether the transformed clone is valid.

This strategy is heavy-weight, and should be used sparingly, but seems
like a good option when the validity of transformations is intricate,
to avoid reimplementing swathes of validation logic in the fuzzer.

Fixes #2919.
2019-12-06 16:38:17 +00:00
Alastair Donaldson
7ee8f443ea
Fix add-dead-break and add-dead-continue passes to respect dominance (#2838)
The implementation of these passes had overlooked the fact that adding
a new edge to a control flow graph can change dominance information.
Adding a dead break/continue risks causing uses to no longer be
dominated by their definitions.  This change introduces various tests
to expose such scenarios, and augments the preconditions for these
transformations with checks to guard against the situation.
2019-09-10 14:48:27 +01:00
Alastair Donaldson
1a89ac8b28
Transformation and fuzzer pass to add dead continues (#2758)
Similar to the existing 'add dead breaks' pass, this adds a pass to
add dead continues to blocks in loops where such a transformation is
viable.  Various functionality common to this new pass and 'add dead
breaks' has been factored into 'fuzzer_util', and some small
improvements to 'add dead breaks' that were identified while reviewing
that code again have been applied.

Fixes #2719.
2019-07-25 13:50:33 +01:00
Alastair Donaldson
dfcb5a1e10
Refactor fuzzer transformations (#2694)
Introduced abstract class for transformations, and refactored all transformations to inherit from this abstract class.
2019-06-25 20:49:46 +01:00
Alastair Donaldson
4a00a80c40
Add fuzzer pass to add dead breaks. (#2654)
This pass randomly add breaks to the merge blocks of selection and
loop constructs, such that the breaking edges will not be dynamically
reachable.
2019-06-05 08:02:16 +01:00