Commit Graph

6 Commits

Author SHA1 Message Date
Alastair Donaldson
502e982956
spirv-fuzz: Fix to TransformationInlineFunction (#3913)
This fixes a problem where TransformationInlineFunction could lead to
distinct instructions having identical unique ids. It adds a validity
check to detect this problem in general.

Fixes #3911.
2020-10-16 22:58:09 +01:00
Alastair Donaldson
538512e8e8
spirv-fuzz: Improve the handling of equation facts (#3281)
The management of equation facts suffered from two problems:

(1) The processing of an equation fact required the data descriptors
    used in the equation to be in canonical form.  However, during
    fact processing it can be deduced that certain data descriptors
    are equivalent, causing their equivalence classes to be merged,
    and that could cause previously canonical data descriptors to no
    longer be canonical.

(2) Related to this, if id equations were known about a canonical data
    descriptor dd1, and other id equations known about a different
    canonical data descriptor dd2, the equation facts about these data
    descriptors were not being merged in the event that dd1 and dd2
    were deduced to be equivalent.

This changes solves (1) by not requiring equation facts to be in
canonical form while processing them, but instead always checking
whether (not necessary canonical) data descriptors are equivalent when
looking for corollaries of equation facts, rather than comparing them
using ==.

Problem (2) is solved by adding logic to merge sets of equations when
data descriptors are made equivalent.

In addition, the change also requires elements to be registered in an
equivalence relation before they can be made equivalent, rather than
being added (if not already present) at the point of being made
equivalent.
2020-04-07 17:38:27 +01:00
Alastair Donaldson
044ecc0b2c
spirv-fuzz: Fuzzer pass to add equation instructions (#3202)
This introduces a new fuzzer pass to add instructions to the module
that define equations, and support in the fact manager for recording
equation facts and deducing synonym facts from equation facts.

Initially the only equations that are supported involve OpIAdd,
OpISub, OpSNegate and OpLogicalNot, but there is scope for adding
support for equations over various other operators.
2020-03-04 14:54:08 +00:00
Alastair Donaldson
fb6bac889e
spirv-fuzz: make equivalence classes deterministic (#3011)
An equivalence relation is computed by traversing the tree of values
rooted at the class's representative. Children were represented by
unordered sets, meaning that the order of values in an equivalence
class could be nondeterministic. This change makes things
deterministic by representing children using a vector.

The path compression optimization employed in the implementation of
the underlying union-find data structure has the potential to change
the order in which elements appear in an equivalence class by changing
the structure of the tree, so the guarantee of determinism is limited
to being a deterministic function of the manner in which the
equivalence relation is updated and inspected.
2019-11-05 15:34:05 +00:00
Alastair Donaldson
f1e5cd73f6
spirv-fuzz: improvements to representation of data synonym facts (#3006)
This change fixes a bug in EquivalenceRelation, changes the interface
of EquivalenceRelation to avoid exposing (potentially
nondeterministic) unordered sets, and changes the interface of
FactManager to allow querying data synonyms directly. These interface
changes have required a lot of corresponding changes to client code
and tests.
2019-11-01 17:50:01 +00:00
Alastair Donaldson
b34fa73193
spirv-fuzz: add class to represent equivalence relation (#2988)
Adds a templated class for representing an equivalence relation on a
value data type.  This will be used by spirv-fuzz for representing
sets of distinct pieces of data in a shader that are known to have
equal values.
2019-10-25 12:46:52 +01:00