Update LibFuzzer w.r.t. the new comparisons instrumentation API

[tch1bo]

Summary

Added the _sanitizer_cov_trace_const_cmp[1248] callbacks. For now they are implemented the same way as _sanitizer_cov_trace_cmp[1248].
For more details, please see https://reviews.llvm.org/D36465.

These changes can be implemented separately from the instrumentation patch and should not break anything in LibFuzzer's work.

[glider]

Could you please upload with -U999999?
Also, probably no need to name the patch [RFC] anymore :)

[glider]

Could you please also upload the context?

lib/Fuzzer/FuzzerTracePC.cpp

397

It would be better to replace this declaration with a macro, but looks like the rest of the file is also doing so :(

415

Missing newline

430

Missing newline

[kcc]

LGTM

[glider]

Landed r310592.

lib/Fuzzer/FuzzerTracePC.cpp

 void __sanitizer_cov_trace_cmp8(uint64_t Arg1, uint64_t Arg2) {
   uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
 }
 
 ATTRIBUTE_INTERFACE
 ATTRIBUTE_NO_SANITIZE_ALL
 ATTRIBUTE_TARGET_POPCNT
+// Now the __sanitizer_cov_trace_const_cmp[1248] callbacks just mimic
+// the behaviour of __sanitizer_cov_trace_cmp[1248] ones. This, however,
+// should be changed later to make full use of instrumentation.
+void __sanitizer_cov_trace_const_cmp8(uint64_t Arg1, uint64_t Arg2) {
+  uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
+  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
+}
+
+ATTRIBUTE_INTERFACE
+ATTRIBUTE_NO_SANITIZE_ALL
+ATTRIBUTE_TARGET_POPCNT
 void __sanitizer_cov_trace_cmp4(uint32_t Arg1, uint32_t Arg2) {
   uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
 }
 
 ATTRIBUTE_INTERFACE
 ATTRIBUTE_NO_SANITIZE_ALL
 ATTRIBUTE_TARGET_POPCNT
+void __sanitizer_cov_trace_const_cmp4(uint32_t Arg1, uint32_t Arg2) {
+  uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
+  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
+}
+
+ATTRIBUTE_INTERFACE
+ATTRIBUTE_NO_SANITIZE_ALL
+ATTRIBUTE_TARGET_POPCNT
 void __sanitizer_cov_trace_cmp2(uint16_t Arg1, uint16_t Arg2) {
   uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
 }
 
 ATTRIBUTE_INTERFACE
 ATTRIBUTE_NO_SANITIZE_ALL
 ATTRIBUTE_TARGET_POPCNT
+void __sanitizer_cov_trace_const_cmp2(uint16_t Arg1, uint16_t Arg2) {
+  uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
+  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
+}
+
+ATTRIBUTE_INTERFACE
+ATTRIBUTE_NO_SANITIZE_ALL
+ATTRIBUTE_TARGET_POPCNT
 void __sanitizer_cov_trace_cmp1(uint8_t Arg1, uint8_t Arg2) {
   uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
   fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
 }
 
 ATTRIBUTE_INTERFACE
 ATTRIBUTE_NO_SANITIZE_ALL
 ATTRIBUTE_TARGET_POPCNT
+void __sanitizer_cov_trace_const_cmp1(uint8_t Arg1, uint8_t Arg2) {
+  uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
+  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
+}
+
+ATTRIBUTE_INTERFACE
+ATTRIBUTE_NO_SANITIZE_ALL
+ATTRIBUTE_TARGET_POPCNT
 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 = reinterpret_cast<uintptr_t>(__builtin_return_address(0));