Commit Graph

8 Commits

Author SHA1 Message Date
Alastair Donaldson
9c4481419e
spirv-fuzz: Allow inapplicable transformations to be ignored (#4407)
spirv-fuzz features transformations that should be applicable by
construction. Assertions are used to detect when such transformations
turn out to be inapplicable. Failures of such assertions indicate bugs
in the fuzzer. However, when using the fuzzer at scale (e.g. in
ClusterFuzz) reports of these assertion failures create noise, and
cause the fuzzer to exit early. This change adds an option whereby
inapplicable transformations can be ignored. This reduces noise and
allows fuzzing to continue even when a transformation that should be
applicable but is not has been erroneously created.
2021-07-28 22:59:37 +01:00
Alastair Donaldson
22eb528f17
spirv-fuzz: Do not add too many dead blocks (#4217)
Profiling has shown that adding large numbers of dead block
transformations can be expensive because each on requires dominator
analysis information, and each one invalidates this information. There
is currently no obvious mechanism for incrementally updating the
dominator analysis. This change restricts the number of these
transformations that a single fuzzer pass will apply, to restrict this
performance bottleneck.
2021-03-27 10:30:23 +00:00
Alastair Donaldson
c0833ce620
spirv-fuzz: Remove destructors from FuzzerPass subclasses (#4209)
Subclasses of FuzzerPass no longer needlessly override the default
destructor of FuzzerPass.
2021-03-23 13:31:27 +00:00
Vasyl Teliman
d6306537dc
spirv-fuzz: Don't use default parameters (#3583)
Fixes #3177.
2020-07-24 07:57:49 +01:00
Stefano Milizia
7dfd9b8680
spirv-fuzz: Implement MaybeApplyTransformation helper function (#3540)
This function can be used to apply a transformation only if it is
applicable and use it wherever this pattern is used.

Fixes #3530.
2020-07-17 13:01:35 +01:00
Vasyl Teliman
2f69ea849a
spirv-fuzz: Remove FuzzerPassAddUsefulConstructs (#3341)
Fixes #3318.
2020-05-19 15:54:55 +01:00
Alastair Donaldson
8d4261bc44
spirv-fuzz: Introduce TransformationContext (#3272)
Some transformations (e.g. TransformationAddFunction) rely on running
the validator to decide whether the transformation is applicable.  A
recent change allowed spirv-fuzz to take validator options, to cater
for the case where a module should be considered valid under
particular conditions.  However, validation during the checking of
transformations had no access to these validator options.

This change introduced TransformationContext, which currently consists
of a fact manager and a set of validator options, but could in the
future have other fields corresponding to other objects that it is
useful to have access to when applying transformations.  Now, instead
of checking and applying transformations in the context of a
FactManager, a TransformationContext is used.  This gives access to
the fact manager as before, and also access to the validator options
when they are needed.
2020-04-02 15:54:46 +01:00
Alastair Donaldson
8013d477ae
spirv-fuzz: add dead blocks (#3135)
This adds a new kind of fact to the fact manager that knows whether a
block is dead - i.e. guaranteed to be statically unreachable - and a
new transformation for adding a selection construct to a CFG that
conditionally branches to a fresh, dead block, such that the branch
will never be dynamically taken. Transformations that may create new
blocks ('split block' and 'outline function') are updated to propagate
dead block facts to newly-created blocks where appropriate. A fuzzer
pass randomly adds dead blocks to the module.

Future transformations will be able to exploit the fact that such
blocks are known to be dead.
2020-01-13 22:04:01 +00:00