Make HeaderLineno a local variable.

[danielcdh]

Summary

As we are using hierarchical profile, there is no need to keep HeaderLineno a member variable.

[dnovillo]

LGTM. Could you update the commit message to clarify a bit why having a hierarchical profile means we don't need to keep the head line number around? Useful for future reference.

Thanks.

lib/Transforms/IPO/SampleProfile.cpp

void findEquivalencesFor(BasicBlock *BB1,
                            SmallVector<BasicBlock *, 8> Descendants,
                            DominatorTreeBase<BasicBlock> *DomTree);
   void propagateWeights(Function &F);
   unsigned visitEdge(Edge E, unsigned *NumUnknownEdges, Edge *UnknownEdge);
   void buildEdges(Function &F);
   bool propagateThroughEdges(Function &F);
   void computeDominanceAndLoopInfo(Function &F);
 
-  /// \brief Line number for the function header. Used to compute absolute
-  /// line numbers from the relative line numbers found in the profile.
-  unsigned HeaderLineno;
-
   /// \brief Map basic blocks to their computed weights.
   ///
   /// The weight of a basic block is defined to be the maximum
   /// of all the instruction weights in that block.
   BlockWeightMap BlockWeights;
 
   /// \brief Map edges to their computed weights.
   ///

 ///
 /// \returns the weight of \p Inst.
 ErrorOr<unsigned>
 SampleProfileLoader::getInstWeight(const Instruction &Inst) const {
   DebugLoc DLoc = Inst.getDebugLoc();
   if (!DLoc)
     return std::error_code();
 
-  unsigned Lineno = DLoc.getLine();
-  if (Lineno < HeaderLineno)
+  const FunctionSamples *FS = findFunctionSamples(Inst);
+  if (!FS)
     return std::error_code();
 
   const DILocation *DIL = DLoc;
-  const FunctionSamples *FS = findFunctionSamples(Inst);
-  if (!FS)
+  unsigned Lineno = DLoc.getLine();
+  unsigned HeaderLineno = DIL->getScope()->getSubprogram()->getLine();
+  if (Lineno < HeaderLineno)
     return std::error_code();
+
   ErrorOr<unsigned> R =
       FS->findSamplesAt(Lineno - HeaderLineno, DIL->getDiscriminator());
   if (R)
     DEBUG(dbgs() << "    " << Lineno << "." << DIL->getDiscriminator() << ":"
                  << Inst << " (line offset: " << Lineno - HeaderLineno << "."
                  << DIL->getDiscriminator() << " - weight: " << R.get()
                  << ")\n");
   return R;

 /// metadata on BB using the computed values for each of its branches.
 ///
 /// \param F The function to query.
 ///
 /// \returns true if \p F was modified. Returns false, otherwise.
 bool SampleProfileLoader::emitAnnotations(Function &F) {
   bool Changed = false;
 
-  // Initialize invariants used during computation and propagation.
-  HeaderLineno = getFunctionLoc(F);
-  if (HeaderLineno == 0)
+  if (getFunctionLoc(F) == 0)
     return false;
 
   DEBUG(dbgs() << "Line number for the first instruction in " << F.getName()
-               << ": " << HeaderLineno << "\n");
+               << ": " << getFunctionLoc(F) << "\n");
 
   Changed |= inlineHotFunctions(F);
 
   // Compute basic block weights.
   Changed |= computeBlockWeights(F);
 
   if (Changed) {
     // Compute dominance and loop info needed for propagation.