[PGO] Disable value profiling on Fuchsia

[paulkirth]

Summary

Fuchsia currently does not support value profiling, so disable it
similar to how ProfileCounterRelocations are enabled for it by default.

[paulkirth]

I don't think we need this for Fuchsia anymore.

llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp

if (!BlockColors.empty()) {
       assert(CV.size() == 1 && "non-unique color for block!");
       Instruction *EHPad = CV.front()->getFirstNonPHI();
       if (EHPad->isEHPad())
         OpBundles.emplace_back("funclet", EHPad);
     }
   }
 }
 
+static bool isValueProfilingDisabled(const Module *M) {
+  Triple TT(M->getTargetTriple());
+  // Fuchsia uses runtime counter relocation by default.
+  return TT.isOSFuchsia() || DisableValueProfiling;
+}
+
 // Visit all edge and instrument the edges not in MST, and do value profiling.
 // Critical edges will be split.
 static void instrumentOneFunc(
     Function &F, Module *M, TargetLibraryInfo &TLI, BranchProbabilityInfo *BPI,
     BlockFrequencyInfo *BFI,
     std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers,
     bool IsCS) {
   // Split indirectbr critical edges here before computing the MST rather than
Builder.CreateCall(
         {Name, CFGHash, Builder.getInt32(NumCounters), Builder.getInt32(I++)});
   }
 
   // Now instrument select instructions:
   FuncInfo.SIVisitor.instrumentSelects(F, &I, NumCounters, FuncInfo.FuncNameVar,
                                        FuncInfo.FunctionHash);
   assert(I == NumCounters);
 
-  if (DisableValueProfiling)
+  if (isValueProfilingDisabled(M))
     return;
 
   NumOfPGOICall += FuncInfo.ValueSites[IPVK_IndirectCallTarget].size();
 
   // Intrinsic function calls do not have funclet operand bundles needed for
   // Windows exception handling attached to them. However, if value profiling is
   // inserted for one of these calls, then a funclet value will need to be set
   // on the instrumentation call based on the funclet coloring.
case VM_annotate:
     return;
   }
 
   llvm_unreachable("Unknown visiting mode");
 }
 
 // Traverse all valuesites and annotate the instructions for all value kind.
 void PGOUseFunc::annotateValueSites() {
-  if (DisableValueProfiling)
+  if (isValueProfilingDisabled(M))
     return;
 
   // Create the PGOFuncName meta data.
   createPGOFuncNameMetadata(F, FuncInfo.FuncName);
 
   for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
     annotateValueSites(Kind);
 }