[libFuzzer] Diff 46 - Expose Sanitizer Coverage's functions that are rewritten with a different implementation.

[mpividori]

Summary

Hi,
We need to expose Sanitizer Coverage's functions that are rewritten with a different implementation, so compiler-rt's libraries have access to it.
In particular, for windows, asan dll needs to access to the new implementation, when doing interception as explained in https://reviews.llvm.org/D28600 .
Thanks,
Marcos

[kcc]

LGTM

llvm/trunk/lib/Fuzzer/FuzzerDefs.h

 #ifdef __clang__  // avoid gcc warning.
 #  define ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize("memory")))
 #  define ALWAYS_INLINE __attribute__((always_inline))
 #else
 #  define ATTRIBUTE_NO_SANITIZE_MEMORY
 #  define ALWAYS_INLINE
 #endif // __clang__
 
+#if LIBFUZZER_WINDOWS
+#define ATTRIBUTE_INTERFACE __declspec(dllexport)
+#else
+#define ATTRIBUTE_INTERFACE __attribute__((visibility("default")))
+#endif
+
 namespace fuzzer {
 
 template <class T> T Min(T a, T b) { return a < b ? a : b; }
 template <class T> T Max(T a, T b) { return a > b ? a : b; }
 
 class Random;
 class Dictionary;
 class DictionaryEntry;

llvm/trunk/lib/Fuzzer/FuzzerTracePC.cpp

inline ALWAYS_INLINE uintptr_t GetPreviousInstructionPc(void* pc) {
   // TODO: this implementation is x86 only.
   // see sanitizer_common GetPreviousInstructionPc for full implementation.
   return reinterpret_cast<uintptr_t>(pc) - 1;
 }
 
 } // namespace fuzzer
 
 extern "C" {
-__attribute__((visibility("default")))
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_pc_guard(uint32_t *Guard) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleTrace(Guard, PC);
 }
 
-__attribute__((visibility("default")))
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_pc_guard_init(uint32_t *Start, uint32_t *Stop) {
   fuzzer::TPC.HandleInit(Start, Stop);
 }
 
-__attribute__((visibility("default")))
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_pc_indir(uintptr_t Callee) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleCallerCallee(PC, Callee);
 }
 
-__attribute__((visibility("default")))
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_cmp8(uint64_t Arg1, uint64_t Arg2) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
 }
-__attribute__((visibility("default")))
+
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_cmp4(uint32_t Arg1, uint32_t Arg2) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
 }
-__attribute__((visibility("default")))
+
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_cmp2(uint16_t Arg1, uint16_t Arg2) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
 }
-__attribute__((visibility("default")))
+
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_cmp1(uint8_t Arg1, uint8_t Arg2) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
 }
 
-__attribute__((visibility("default")))
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_switch(uint64_t Val, uint64_t *Cases) {
   uint64_t N = Cases[0];
   uint64_t ValSizeInBits = Cases[1];
   uint64_t *Vals = Cases + 2;
   // Skip the most common and the most boring case.
   if (Vals[N - 1]  < 256 && Val < 256)
     return;
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   size_t i;
   uint64_t Token = 0;
   for (i = 0; i < N; i++) {
     Token = Val ^ Vals[i];
     if (Val < Vals[i])
       break;
   }
 
   if (ValSizeInBits == 16)
     fuzzer::TPC.HandleCmp(PC + i, static_cast<uint16_t>(Token), (uint16_t)(0));
   else if (ValSizeInBits == 32)
     fuzzer::TPC.HandleCmp(PC + i, static_cast<uint32_t>(Token), (uint32_t)(0));
   else
     fuzzer::TPC.HandleCmp(PC + i, Token, (uint64_t)(0));
 }
 
-__attribute__((visibility("default")))
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_div4(uint32_t Val) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Val, (uint32_t)0);
 }
-__attribute__((visibility("default")))
+
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_div8(uint64_t Val) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Val, (uint64_t)0);
 }
-__attribute__((visibility("default")))
+
+ATTRIBUTE_INTERFACE
 void __sanitizer_cov_trace_gep(uintptr_t Idx) {
   uintptr_t PC = fuzzer::GetPreviousInstructionPc(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Idx, (uintptr_t)0);
 }
-
 }  // extern "C"