[libFuzzer] refactor the handling of instrumentation counters so that they are grouped in regions one full page each. Needed for future optimization. NFC
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@352603 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/FuzzerTracePC.h b/FuzzerTracePC.h
index 505b827..2ab75b8 100644
--- a/FuzzerTracePC.h
+++ b/FuzzerTracePC.h
@@ -125,10 +125,38 @@
bool DoPrintNewPCs = false;
size_t NumPrintNewFuncs = 0;
- struct { uint8_t *Start, *Stop; } ModuleCounters[4096];
- size_t NumModulesWithInline8bitCounters; // linker-initialized.
+ // Module represents the array of 8-bit counters split into regions
+ // such that every region, except maybe the first and the last one, is one
+ // full page.
+ struct Module {
+ struct Region {
+ uint8_t *Start, *Stop;
+ bool Enabled;
+ bool OneFullPage;
+ };
+ Region *Regions;
+ size_t NumRegions;
+ uint8_t *Start() { return Regions[0].Start; }
+ uint8_t *Stop() { return Regions[NumRegions - 1].Stop; }
+ size_t Size() { return Stop() - Start(); }
+ size_t Idx(uint8_t *P) {
+ assert(P >= Start() && P < Stop());
+ return P - Start();
+ }
+ };
+
+ Module Modules[4096];
+ size_t NumModules; // linker-initialized.
size_t NumInline8bitCounters;
+ template <class Callback>
+ void IterateCounterRegions(Callback CB) {
+ for (size_t m = 0; m < NumModules; m++)
+ for (size_t r = 0; r < Modules[m].NumRegions; r++)
+ CB(Modules[m].Regions[r]);
+ }
+
+
struct PCTableEntry {
uintptr_t PC, PCFlags;
};
@@ -140,7 +168,7 @@
Set<uintptr_t> ObservedPCs;
std::unordered_map<uintptr_t, uintptr_t> ObservedFuncs; // PC => Counter.
- std::pair<size_t, size_t> FocusFunction = {-1, -1}; // Module and PC IDs.
+ uint8_t *FocusFunctionCounterPtr = nullptr;
ValueBitMap ValueProfileMap;
uintptr_t InitialStack;
@@ -149,7 +177,7 @@
template <class Callback>
// void Callback(size_t FirstFeature, size_t Idx, uint8_t Value);
ATTRIBUTE_NO_SANITIZE_ALL
-void ForEachNonZeroByte(const uint8_t *Begin, const uint8_t *End,
+size_t ForEachNonZeroByte(const uint8_t *Begin, const uint8_t *End,
size_t FirstFeature, Callback Handle8bitCounter) {
typedef uintptr_t LargeType;
const size_t Step = sizeof(LargeType) / sizeof(uint8_t);
@@ -171,6 +199,7 @@
for (; P < End; P++)
if (uint8_t V = *P)
Handle8bitCounter(FirstFeature, P - Begin, V);
+ return End - Begin;
}
// Given a non-zero Counter returns a number in the range [0,7].
@@ -213,17 +242,18 @@
size_t FirstFeature = 0;
- if (NumInline8bitCounters) {
- for (size_t i = 0; i < NumModulesWithInline8bitCounters; i++) {
- ForEachNonZeroByte(ModuleCounters[i].Start, ModuleCounters[i].Stop,
- FirstFeature, Handle8bitCounter);
- FirstFeature += 8 * (ModuleCounters[i].Stop - ModuleCounters[i].Start);
+ for (size_t i = 0; i < NumModules; i++) {
+ for (size_t r = 0; r < Modules[i].NumRegions; r++) {
+ if (!Modules[i].Regions[r].Enabled) continue;
+ FirstFeature += 8 * ForEachNonZeroByte(Modules[i].Regions[r].Start,
+ Modules[i].Regions[r].Stop,
+ FirstFeature, Handle8bitCounter);
}
}
- ForEachNonZeroByte(ExtraCountersBegin(), ExtraCountersEnd(), FirstFeature,
- Handle8bitCounter);
- FirstFeature += (ExtraCountersEnd() - ExtraCountersBegin()) * 8;
+ FirstFeature +=
+ 8 * ForEachNonZeroByte(ExtraCountersBegin(), ExtraCountersEnd(),
+ FirstFeature, Handle8bitCounter);
if (UseValueProfileMask) {
ValueProfileMap.ForEach([&](size_t Idx) {