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https://github.com/KhronosGroup/SPIRV-Tools
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8d4261bc44
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.
119 lines
5.2 KiB
C++
119 lines
5.2 KiB
C++
// Copyright (c) 2019 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "source/fuzz/fuzzer_pass_adjust_loop_controls.h"
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#include "source/fuzz/transformation_set_loop_control.h"
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namespace spvtools {
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namespace fuzz {
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FuzzerPassAdjustLoopControls::FuzzerPassAdjustLoopControls(
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opt::IRContext* ir_context, TransformationContext* transformation_context,
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FuzzerContext* fuzzer_context,
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protobufs::TransformationSequence* transformations)
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: FuzzerPass(ir_context, transformation_context, fuzzer_context,
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transformations) {}
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FuzzerPassAdjustLoopControls::~FuzzerPassAdjustLoopControls() = default;
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void FuzzerPassAdjustLoopControls::Apply() {
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// Consider every merge instruction in the module (via looking through all
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// functions and blocks).
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for (auto& function : *GetIRContext()->module()) {
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for (auto& block : function) {
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if (auto merge_inst = block.GetMergeInst()) {
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// Ignore the instruction if it is not a loop merge.
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if (merge_inst->opcode() != SpvOpLoopMerge) {
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continue;
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}
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// Decide randomly whether to adjust this loop merge.
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if (!GetFuzzerContext()->ChoosePercentage(
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GetFuzzerContext()->GetChanceOfAdjustingLoopControl())) {
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continue;
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}
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uint32_t existing_mask = merge_inst->GetSingleWordOperand(
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TransformationSetLoopControl::kLoopControlMaskInOperandIndex);
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// First, set the new mask to one of None, Unroll or DontUnroll.
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std::vector<uint32_t> basic_masks = {SpvLoopControlMaskNone,
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SpvLoopControlUnrollMask,
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SpvLoopControlDontUnrollMask};
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uint32_t new_mask =
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basic_masks[GetFuzzerContext()->RandomIndex(basic_masks)];
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// For the loop controls that depend on guarantees about what the loop
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// does, check which of these were present in the existing mask and
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// randomly decide whether to keep them. They are just hints, so
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// removing them should not change the semantics of the module.
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for (auto mask_bit :
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{SpvLoopControlDependencyInfiniteMask,
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SpvLoopControlDependencyLengthMask,
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SpvLoopControlMinIterationsMask, SpvLoopControlMaxIterationsMask,
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SpvLoopControlIterationMultipleMask}) {
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if ((existing_mask & mask_bit) && GetFuzzerContext()->ChooseEven()) {
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// The mask bits we are considering are not available in all SPIR-V
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// versions. However, we only include a mask bit if it was present
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// in the original loop control mask, and we work under the
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// assumption that we are transforming a valid module, thus we don't
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// need to actually check whether the SPIR-V version being used
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// supports these loop control mask bits.
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new_mask |= mask_bit;
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}
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}
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// We use 0 for peel count and partial count in the case that we choose
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// not to set these controls.
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uint32_t peel_count = 0;
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uint32_t partial_count = 0;
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// PeelCount and PartialCount are not compatible with DontUnroll, so
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// we check whether DontUnroll is set.
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if (!(new_mask & SpvLoopControlDontUnrollMask)) {
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// If PeelCount is supported by this SPIR-V version, randomly choose
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// whether to set it. If it was set in the original mask and is not
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// selected for setting here, that amounts to dropping it.
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if (TransformationSetLoopControl::PeelCountIsSupported(
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GetIRContext()) &&
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GetFuzzerContext()->ChooseEven()) {
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new_mask |= SpvLoopControlPeelCountMask;
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// The peel count is chosen randomly - if PeelCount was already set
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// this will overwrite whatever peel count was previously used.
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peel_count = GetFuzzerContext()->GetRandomLoopControlPeelCount();
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}
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// Similar, but for PartialCount.
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if (TransformationSetLoopControl::PartialCountIsSupported(
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GetIRContext()) &&
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GetFuzzerContext()->ChooseEven()) {
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new_mask |= SpvLoopControlPartialCountMask;
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partial_count =
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GetFuzzerContext()->GetRandomLoopControlPartialCount();
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}
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}
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// Apply the transformation and add it to the output transformation
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// sequence.
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TransformationSetLoopControl transformation(block.id(), new_mask,
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peel_count, partial_count);
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ApplyTransformation(transformation);
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}
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}
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}
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}
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} // namespace fuzz
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} // namespace spvtools
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