[libFuzzer] remove the experimental support for clang coverage instrumentation. This mode has not been used and our experiments with https://github.com/google/fuzzer-test-suite show that this signal is weaker than the SanitizerCoverage

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@332034 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 49 deletions

diff --git a/lib/fuzzer/FuzzerClangCounters.cpp b/lib/fuzzer/FuzzerClangCounters.cpp
deleted file mode 100644
index f69e922cf..000000000
--- a/lib/fuzzer/FuzzerClangCounters.cpp
+++ /dev/null
@@ -1,49 +0,0 @@
-//===- FuzzerExtraCounters.cpp - Extra coverage counters ------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-// Coverage counters from Clang's SourceBasedCodeCoverage.
-//===----------------------------------------------------------------------===//
-
-// Support for SourceBasedCodeCoverage is experimental:
-// * Works only for the main binary, not DSOs yet.
-// * Works only on Linux.
-// * Does not implement print_pcs/print_coverage yet.
-// * Is not fully evaluated for performance and sensitivity.
-//   We expect large performance drop due to 64-bit counters,
-//   and *maybe* better sensitivity due to more fine-grained counters.
-//   Preliminary comparison on a single benchmark (RE2) shows
-//   a bit worse sensitivity though.
-
-#include "FuzzerDefs.h"
-
-#if LIBFUZZER_LINUX
-__attribute__((weak)) extern uint64_t __start___llvm_prf_cnts;
-__attribute__((weak)) extern uint64_t __stop___llvm_prf_cnts;
-namespace fuzzer {
-uint64_t *ClangCountersBegin() { return &__start___llvm_prf_cnts; }
-uint64_t *ClangCountersEnd() { return &__stop___llvm_prf_cnts; }
-}  // namespace fuzzer
-#else
-// TODO: Implement on Mac (if the data shows it's worth it).
-//__attribute__((visibility("hidden")))
-//extern uint64_t CountersStart __asm("section$start$__DATA$__llvm_prf_cnts");
-//__attribute__((visibility("hidden")))
-//extern uint64_t CountersEnd __asm("section$end$__DATA$__llvm_prf_cnts");
-namespace fuzzer {
-uint64_t *ClangCountersBegin() { return nullptr; }
-uint64_t *ClangCountersEnd() { return  nullptr; }
-}  // namespace fuzzer
-#endif
-
-namespace fuzzer {
-ATTRIBUTE_NO_SANITIZE_ALL
-void ClearClangCounters() {  // hand-written memset, don't asan-ify.
-  for (auto P = ClangCountersBegin(); P < ClangCountersEnd(); P++)
-    *P = 0;
-}
-}