This PR introduces a new fuzzer pass, which:
- finds all integer vectors or constants
- finds or creates the corresponding constants with opposite
signedness
- records such constants as synonyms of the first ones
- replaces the usages of the original constants with the new ones
if allowed
Fixes#2677.
This fuzzer pass:
For each zero-like constant, either finds the existing definition of
the corresponding toggled one (OpConstantNull becomes zero-valued
scalar OpConstant or vice versa) or creates a new one if it doesn't
exist and records that the two are synonyms
For each use of these constants, probabilistically decides whether to
change it with the corresponding toggled constant id (as described in
#3486 )
Only uses inside blocks of instructions are considered and not, for
example, in instructions declaring other constants.
In this PR, the classes that represent the adjust branch weights
transformation and fuzzer pass were implemented. This transformation
adjusts the branch weights of a OpBranchConditional instruction.
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.
In this PR, the classes that represent the toggle access chain
instruction transformation and fuzzer pass were implemented. This
transformation toggles the instructions OpAccessChain and
OpInBoundsAccessChain between them.
Fixes#3193.
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.
This change adds a fuzzer pass that sprinkles access chain
instructions into a module at random. This allows other passes to
have a richer set of pointers available to them, in particular the
passes that add loads and stores.
Adds a fuzzer pass that inserts function calls into the module at
random. Calls from dead blocks can be arbitrary (so long as they do
not introduce recursion), while calls from other blocks can only be to
livesafe functions.
The change fixes some oversights in transformations to replace
constants with uniforms and to obfuscate constants which testing of
this fuzzer pass identified.
This change adds fuzzer passes that sprinkle loads and stores into a
module at random, with stores restricted to occur in either dead
blocks, or to use pointers for which it is known that the pointee
value does not influence the module's overall behaviour.
The change also generalises the VariableValueIsArbitrary fact to
PointeeValueIsIrrelevant, to allow stores through access chains or
object copies of variables whose values are known to be irrelevant.
The change includes some other minor refactorings.
Adds two new fuzzer passes to add variables to a module: one that adds
Private storage class global variables, another that adds Function
storage class local variables.
Adds a fuzzer pass that randomly adds vector and matrix types not
already present in the module, and randomly adds structs with random
field types and arrays with random base types and sizes. Other passes
will be able to create variables and ids using these types.
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.
This change adds a fuzzer pass that allows code from other SPIR-V
modules to be donated into the module under transformation. It also
changes the command-line options of the tools so that, in fuzzing
mode, a file must be specified that contains the names of available
donor modules.
A new transformation and associated fuzzer pass in spirv-fuzz that
selects single-entry single-exit control flow graph regions and for
each selected region outlines the region into a new function and
replaces the original region with a call to this function.
Adds an option to run the validator on the SPIR-V binary after each
fuzzer pass has been applied, to help identify when the fuzzer has
made the module invalid. Also adds a helper method to allow dumping
of the sequence of transformations that have been applied to a JSON
file.
A new pass that gives spirv-fuzz the ability to adjust the memory
operand masks associated with memory access instructions (such as
OpLoad and OpCopy Memory).
Fixes#2940.
A new pass that allows the fuzzer to change the 'loop control' operand
(and associated literal operands) of OpLoopMerge instructions.
Fixes#2938.
Fixes#2943.
Adds a fuzzer pass and transformation to create a composite (array,
matrix, struct or vector) from available constituent components, and
inform the fact manager that each component of the new composite is
synonymous with the id that was used to construct it. This allows the
"replace id with synonym" pass to then replace uses of said ids with
uses of elements extracted from the composite.
Fixes#2858.
This change to spirv-fuzz uses ideas from "Swarm Testing" (Groce et al. 2012), so that a random subset of fuzzer passes are enabled. These passes are then applied repeatedly in a randomized fashion, with the aggression with which they are applied being randomly chosen per pass.
There is plenty of scope for refining the probabilities introduce in this change; this is just meant to be a reasonable first effort.
If the fuzzer's fact manager knows that ids A and B are synonymous, it
can replace a use of A with a use of B, so long as various conditions
hold (e.g. the definition of B must dominate the use of A, and it is
not legal to replace a use of an OpConstant in a struct's access chain
with a synonym that is not an OpConstant).
This change adds a fuzzer pass to sprinke such synonym replacements
through the module.
A new fuzzer pass that randomly introduces OpCopyObject instructions
that make copies of ids, and uses the fact manager to record the fact
that an id %id is synonymous with an id generated by an OpCopyObject
applied to %id. (A future pass will exploit such synonym facts.)
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.
Adds to spirv-fuzz the option to shrink a sequence of transformations
that lead to an interesting binary to be generated, to find a smaller
sub-sequence of transformations that still lead to an interesting (but
hopefully simpler) binary being generated. The notion of what counts
as "interesting" comes from a user-provided script, the
"interestingness function", similar to the way the spirv-reduce tool
works. The shrinking process will give up after a maximum number of
steps, which can be configured on the command line.
Tests for the combination of fuzzing and shrinking are included, using
a variety of interestingness functions.
Fixes#2621.
Instead of aborting when an invalid input fact is provided, the tool
now warns about the invalid fact and then ignores it. This is
convenient for example if facts are specified about uniforms with
descriptor sets and bindings that happen to not be present in the
input binary.
Adds a new transformation that can replace a constant with a uniform known to have the same value, and adds a fuzzer pass that (a) replaces a boolean with a comparison of literals (e.g. replacing "true" with "42 > 24"), and then (b) obfuscates the literals appearing in this comparison by replacing them with identically-valued uniforms, if available.
The fuzzer_replayer test file has also been updated to allow initial facts to be provided, and to do error checking of the status results returned by the fuzzer and replayer components.
This new pass adds some basic ingredients to a module on which future
passes are likely to depend, such as boolean constants and some
specfic integer and floating-point values. This is not a fuzzer pass
in the true sense in that it does not employ randomization, but it
makes sense to define it as a fuzzer pass since it is the first of a
number of transformations passes that the fuzzer will run on a module.
With this pass, the fuzzer can split blocks in the input module. This
is mainly useful in order to give other (future) transformations more
opportunities to apply.
