tsan: don't subtract one from fake PCs

These are fake and not actual PCs, more like function IDs.
Pass them to external symbolizer untouched.

llvm-svn: 224022

compiler-rt/lib/tsan/rtl/tsan_rtl_report.cc

@@ -111,13 +111,14 @@ static ReportStack *SymbolizeStack(StackTrace trace) {
   SymbolizedStack *top = nullptr;
   for (uptr si = 0; si < trace.size; si++) {
     const uptr pc = trace.trace[si];
+    uptr pc1 = pc;
 #ifndef SANITIZER_GO
     // We obtain the return address, but we're interested in the previous
     // instruction.
-    const uptr pc1 = StackTrace::GetPreviousInstructionPc(pc);
+    if ((pc & kExternalPCBit) == 0)
+      pc1 = StackTrace::GetPreviousInstructionPc(pc);
 #else
     // FIXME(dvyukov): Go sometimes uses address of a function as top pc.
-    uptr pc1 = pc;
     if (si != trace.size - 1)
       pc1 -= 1;
 #endif

compiler-rt/lib/tsan/rtl/tsan_symbolize.cc

@@ -36,10 +36,6 @@ void ExitSymbolizer() {
   thr->ignore_interceptors--;
 }
 
-// Denotes fake PC values that come from JIT/JAVA/etc.
-// For such PC values __tsan_symbolize_external() will be called.
-const uptr kExternalPCBit = 1ULL << 60;
-
 // May be overriden by JIT/JAVA/etc,
 // whatever produces PCs marked with kExternalPCBit.
 extern "C" bool __tsan_symbolize_external(uptr pc,

compiler-rt/lib/tsan/rtl/tsan_symbolize.h

@@ -18,6 +18,10 @@
 
 namespace __tsan {
 
+// Denotes fake PC values that come from JIT/JAVA/etc.
+// For such PC values __tsan_symbolize_external() will be called.
+const uptr kExternalPCBit = 1ULL << 60;
+
 void EnterSymbolizer();
 void ExitSymbolizer();
 SymbolizedStack *SymbolizeCode(uptr addr);