[libFuzzer] improve support for inline-8bit-counters (make it more correct and faster)

llvm-svn: 309443

3 files changed, 21 insertions, 3 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerTracePC.cpp b/llvm/lib/Fuzzer/FuzzerTracePC.cpp
index 07be441244c..bf2a6110e85 100644
--- a/llvm/lib/Fuzzer/FuzzerTracePC.cpp
+++ b/llvm/lib/Fuzzer/FuzzerTracePC.cpp
@@ -309,6 +309,14 @@ static size_t InternalStrnlen2(const char *S1, const char *S2) {
   return Len;
 }
 
+void TracePC::ClearInlineCounters() {
+  for (size_t i = 0; i < NumModulesWithInline8bitCounters; i++) {
+    uint8_t *Beg = ModuleCounters[i].Start;
+    size_t Size = ModuleCounters[i].Stop - Beg;
+    memset(Beg, 0, Size);
+  }
+}
+
 } // namespace fuzzer
 
 extern "C" {
@@ -345,6 +353,10 @@ void __sanitizer_cov_8bit_counters_init(uint8_t *Start, uint8_t *Stop) {
 }
 
 ATTRIBUTE_INTERFACE
+void __sanitizer_cov_pcs_init(const uint8_t *pcs_beg, const uint8_t *pcs_end) {
+}
+
+ATTRIBUTE_INTERFACE
 ATTRIBUTE_NO_SANITIZE_ALL
 void __sanitizer_cov_trace_pc_indir(uintptr_t Callee) {
   uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
diff --git a/llvm/lib/Fuzzer/FuzzerTracePC.h b/llvm/lib/Fuzzer/FuzzerTracePC.h
index fac2b2b9cc8..28301d17b2c 100644
--- a/llvm/lib/Fuzzer/FuzzerTracePC.h
+++ b/llvm/lib/Fuzzer/FuzzerTracePC.h
@@ -87,8 +87,11 @@ class TracePC {
     ValueProfileMap.Reset();
     memset(Counters(), 0, GetNumPCs());
     ClearExtraCounters();
+    ClearInlineCounters();
   }
 
+  void ClearInlineCounters();
+
   void UpdateFeatureSet(size_t CurrentElementIdx, size_t CurrentElementSize);
   void PrintFeatureSet();
 
@@ -201,8 +204,11 @@ void TracePC::CollectFeatures(Callback HandleFeature) const {
   };
 
   size_t FirstFeature = 0;
-  ForEachNonZeroByte(Counters, Counters + N, FirstFeature, Handle8bitCounter);
-  FirstFeature += N * 8;
+  if (!NumInline8bitCounters) {
+    ForEachNonZeroByte(Counters, Counters + N, FirstFeature, Handle8bitCounter);
+    FirstFeature += N * 8;
+  }
+
   for (size_t i = 0; i < NumModulesWithInline8bitCounters; i++) {
     ForEachNonZeroByte(ModuleCounters[i].Start, ModuleCounters[i].Stop,
                        FirstFeature, Handle8bitCounter);
diff --git a/llvm/lib/Fuzzer/test/fuzzer-traces-hooks.test b/llvm/lib/Fuzzer/test/fuzzer-traces-hooks.test
index 77ca4b47bd0..3f9f89e461f 100644
--- a/llvm/lib/Fuzzer/test/fuzzer-traces-hooks.test
+++ b/llvm/lib/Fuzzer/test/fuzzer-traces-hooks.test
@@ -3,7 +3,7 @@
 UNSUPPORTED: windows
 CHECK: BINGO
 
-RUN: not LLVMFuzzer-MemcmpTest               -seed=1 -runs=2000000   2>&1 | FileCheck %s
+RUN: not LLVMFuzzer-MemcmpTest               -seed=1 -runs=10000000   2>&1 | FileCheck %s
 RUN: not LLVMFuzzer-StrncmpTest              -seed=1 -runs=2000000   2>&1 | FileCheck %s
 RUN: not LLVMFuzzer-StrcmpTest               -seed=1 -runs=2000000   2>&1 | FileCheck %s
 RUN: not LLVMFuzzer-StrstrTest               -seed=1 -runs=2000000   2>&1 | FileCheck %s