spirv-fuzz: Fixes to pass management (#4011)
diff --git a/source/fuzz/fuzzer.cpp b/source/fuzz/fuzzer.cpp
index 5424afc..40da497 100644
--- a/source/fuzz/fuzzer.cpp
+++ b/source/fuzz/fuzzer.cpp
@@ -383,10 +383,19 @@
// Stop because we have reached the transformation limit.
return false;
}
+ // If we have applied T transformations so far, and the limit on the number of
+ // transformations to apply is L (where T < L), the chance that we will
+ // continue fuzzing is:
+ //
+ // 1 - T/(2*L)
+ //
+ // That is, the chance of continuing decreases as more transformations are
+ // applied. Using 2*L instead of L increases the number of transformations
+ // that are applied on average.
auto chance_of_continuing = static_cast<uint32_t>(
- 100.0 *
- (1.0 - (static_cast<double>(transformations_applied_so_far) /
- static_cast<double>(fuzzer_context_->GetTransformationLimit()))));
+ 100.0 * (1.0 - (static_cast<double>(transformations_applied_so_far) /
+ (2.0 * static_cast<double>(
+ fuzzer_context_->GetTransformationLimit())))));
if (!fuzzer_context_->ChoosePercentage(chance_of_continuing)) {
// We have probabilistically decided to stop.
return false;
diff --git a/source/fuzz/fuzzer_context.cpp b/source/fuzz/fuzzer_context.cpp
index 7f9efb7..47bf4e2 100644
--- a/source/fuzz/fuzzer_context.cpp
+++ b/source/fuzz/fuzzer_context.cpp
@@ -29,10 +29,10 @@
// Default <minimum, maximum> pairs of probabilities for applying various
// transformations. All values are percentages. Keep them in alphabetical order.
const std::pair<uint32_t, uint32_t>
- kChanceOfAcceptingRepeatedPassRecommendation = {70, 100};
+ kChanceOfAcceptingRepeatedPassRecommendation = {50, 80};
const std::pair<uint32_t, uint32_t> kChanceOfAddingAccessChain = {5, 50};
-const std::pair<uint32_t, uint32_t> kChanceOfAddingAnotherPassToPassLoop = {85,
- 95};
+const std::pair<uint32_t, uint32_t> kChanceOfAddingAnotherPassToPassLoop = {50,
+ 90};
const std::pair<uint32_t, uint32_t> kChanceOfAddingAnotherStructField = {20,
90};
const std::pair<uint32_t, uint32_t> kChanceOfAddingArrayOrStructType = {20, 90};
diff --git a/source/fuzz/pass_management/repeated_pass_manager_random_with_recommendations.cpp b/source/fuzz/pass_management/repeated_pass_manager_random_with_recommendations.cpp
index 920d13f..6d77f25 100644
--- a/source/fuzz/pass_management/repeated_pass_manager_random_with_recommendations.cpp
+++ b/source/fuzz/pass_management/repeated_pass_manager_random_with_recommendations.cpp
@@ -53,6 +53,8 @@
result = recommended_passes_.front();
recommended_passes_.pop_front();
}
+ assert(result != nullptr && "A pass must have been chosen.");
+ last_pass_choice_ = result;
return result;
}
