From f15adebe757b91340c7540dd1618af2aeb0d1fca Mon Sep 17 00:00:00 2001
From: Kostya Serebryany <kcc@google.com>
Date: Mon, 31 Jul 2017 20:20:59 +0000
Subject: [PATCH] [libFuzzer] implement __sanitizer_cov_pcs_init and add
 pc-table to build flags for one test (for now)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309615 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Fuzzer/FuzzerTracePC.cpp                  | 31 ++++++++++++++++---
 lib/Fuzzer/FuzzerTracePC.h                    |  5 +++
 .../test/inline-8bit-counters/CMakeLists.txt  |  2 +-
 3 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/lib/Fuzzer/FuzzerTracePC.cpp b/lib/Fuzzer/FuzzerTracePC.cpp
index bf2a6110e85..1c4c24032fc 100644
--- a/lib/Fuzzer/FuzzerTracePC.cpp
+++ b/lib/Fuzzer/FuzzerTracePC.cpp
@@ -66,6 +66,15 @@ void TracePC::HandleInline8bitCountersInit(uint8_t *Start, uint8_t *Stop) {
   NumInline8bitCounters += Stop - Start;
 }
 
+void TracePC::HandlePCsInit(const uint8_t *Start, const uint8_t *Stop) {
+  const uintptr_t *B = reinterpret_cast<const uintptr_t *>(Start);
+  const uintptr_t *E = reinterpret_cast<const uintptr_t *>(Stop);
+  if (NumPCTables && ModulePCTable[NumPCTables - 1].Start == B) return;
+  assert(NumPCTables < sizeof(ModulePCTable) / sizeof(ModulePCTable[0]));
+  ModulePCTable[NumPCTables++] = {B, E};
+  NumPCsInPCTables = E - B;
+}
+
 void TracePC::HandleInit(uint32_t *Start, uint32_t *Stop) {
   if (Start == Stop || *Start) return;
   assert(NumModules < sizeof(Modules) / sizeof(Modules[0]));
@@ -85,17 +94,28 @@ void TracePC::HandleInit(uint32_t *Start, uint32_t *Stop) {
 }
 
 void TracePC::PrintModuleInfo() {
-  Printf("INFO: Loaded %zd modules (%zd guards): ", NumModules, NumGuards);
-  for (size_t i = 0; i < NumModules; i++)
-    Printf("[%p, %p), ", Modules[i].Start, Modules[i].Stop);
-  Printf("\n");
+  if (NumGuards) {
+    Printf("INFO: Loaded %zd modules (%zd guards): ", NumModules, NumGuards);
+    for (size_t i = 0; i < NumModules; i++)
+      Printf("[%p, %p), ", Modules[i].Start, Modules[i].Stop);
+    Printf("\n");
+  }
   if (NumModulesWithInline8bitCounters) {
-    Printf("INFO: Loaded %zd modules with %zd inline 8-bit counters\n",
+    Printf("INFO: Loaded %zd modules with %zd inline 8-bit counters: ",
            NumModulesWithInline8bitCounters, NumInline8bitCounters);
     for (size_t i = 0; i < NumModulesWithInline8bitCounters; i++)
       Printf("[%p, %p), ", ModuleCounters[i].Start, ModuleCounters[i].Stop);
     Printf("\n");
   }
+  if (NumPCTables) {
+    Printf("INFO: Loaded %zd PC tables,   %zd PCs: ", NumPCTables,
+           NumPCsInPCTables);
+    for (size_t i = 0; i < NumPCTables; i++) {
+      Printf("[%p,%p), ", ModulePCTable[i].Start, ModulePCTable[i].Stop,
+             ModulePCTable[i].Stop - ModulePCTable[i].Start);
+    }
+    Printf("\n");
+  }
 }
 
 ATTRIBUTE_NO_SANITIZE_ALL
@@ -354,6 +374,7 @@ 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) {
+  fuzzer::TPC.HandlePCsInit(pcs_beg, pcs_end);
 }
 
 ATTRIBUTE_INTERFACE
diff --git a/lib/Fuzzer/FuzzerTracePC.h b/lib/Fuzzer/FuzzerTracePC.h
index 28301d17b2c..1ad5cf1d1cc 100644
--- a/lib/Fuzzer/FuzzerTracePC.h
+++ b/lib/Fuzzer/FuzzerTracePC.h
@@ -75,6 +75,7 @@ class TracePC {
 
   void HandleInit(uint32_t *Start, uint32_t *Stop);
   void HandleInline8bitCountersInit(uint8_t *Start, uint8_t *Stop);
+  void HandlePCsInit(const uint8_t *Start, const uint8_t *Stop);
   void HandleCallerCallee(uintptr_t Caller, uintptr_t Callee);
   template <class T> void HandleCmp(uintptr_t PC, T Arg1, T Arg2);
   size_t GetTotalPCCoverage();
@@ -149,6 +150,10 @@ private:
   size_t NumModulesWithInline8bitCounters;  // linker-initialized.
   size_t NumInline8bitCounters;
 
+  struct { const uintptr_t *Start, *Stop; } ModulePCTable[4096];
+  size_t NumPCTables;
+  size_t NumPCsInPCTables;
+
   uint8_t *Counters() const;
   uintptr_t *PCs() const;
 
diff --git a/lib/Fuzzer/test/inline-8bit-counters/CMakeLists.txt b/lib/Fuzzer/test/inline-8bit-counters/CMakeLists.txt
index 088ab04fe6a..6b8bdbb5c5e 100644
--- a/lib/Fuzzer/test/inline-8bit-counters/CMakeLists.txt
+++ b/lib/Fuzzer/test/inline-8bit-counters/CMakeLists.txt
@@ -1,7 +1,7 @@
 # These tests are instrumented with -fsanitize-coverage=inline-8bit-counters
 
 set(CMAKE_CXX_FLAGS
-  "${LIBFUZZER_FLAGS_BASE} -fno-sanitize-coverage=trace-pc-guard -fsanitize-coverage=inline-8bit-counters")
+  "${LIBFUZZER_FLAGS_BASE} -fno-sanitize-coverage=trace-pc-guard -fsanitize-coverage=inline-8bit-counters,pc-table")
 
 set(Inline8bitCounterTests
   SimpleTest
-- 
2.40.0