[SampleProf] NFC. Expose reusable functionality in SampleProfile.

Summary:
Exposing getOffset and findFunctionSamples as members of
SampleProfile. They are intimately tied to design choices of the
sample profile format - using offsets instead of line numbers, and
traversing inlined functions stack, respectively.

Reviewers: davidxl

Reviewed By: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D43605

llvm-svn: 325747
diff --git a/llvm/lib/Transforms/IPO/SampleProfile.cpp b/llvm/lib/Transforms/IPO/SampleProfile.cpp
index a8d1be7..1cb61ff 100644
--- a/llvm/lib/Transforms/IPO/SampleProfile.cpp
+++ b/llvm/lib/Transforms/IPO/SampleProfile.cpp
@@ -217,7 +217,6 @@
   void buildEdges(Function &F);
   bool propagateThroughEdges(Function &F, bool UpdateBlockCount);
   void computeDominanceAndLoopInfo(Function &F);
-  unsigned getOffset(const DILocation *DIL) const;
   void clearFunctionData();
 
   /// \brief Map basic blocks to their computed weights.
@@ -473,13 +472,6 @@
   CoverageTracker.clear();
 }
 
-/// Returns the line offset to the start line of the subprogram.
-/// We assume that a single function will not exceed 65535 LOC.
-unsigned SampleProfileLoader::getOffset(const DILocation *DIL) const {
-  return (DIL->getLine() - DIL->getScope()->getSubprogram()->getLine()) &
-         0xffff;
-}
-
 #ifndef NDEBUG
 /// \brief Print the weight of edge \p E on stream \p OS.
 ///
@@ -549,7 +541,7 @@
     return 0;
 
   const DILocation *DIL = DLoc;
-  uint32_t LineOffset = getOffset(DIL);
+  uint32_t LineOffset = FunctionSamples::getOffset(DIL);
   uint32_t Discriminator = DIL->getBaseDiscriminator();
   ErrorOr<uint64_t> R = FS->findSamplesAt(LineOffset, Discriminator);
   if (R) {
@@ -649,8 +641,9 @@
   if (FS == nullptr)
     return nullptr;
 
-  return FS->findFunctionSamplesAt(
-      LineLocation(getOffset(DIL), DIL->getBaseDiscriminator()), CalleeName);
+  return FS->findFunctionSamplesAt(LineLocation(FunctionSamples::getOffset(DIL),
+                                                DIL->getBaseDiscriminator()),
+                                   CalleeName);
 }
 
 /// Returns a vector of FunctionSamples that are the indirect call targets
@@ -670,7 +663,7 @@
   if (FS == nullptr)
     return R;
 
-  uint32_t LineOffset = getOffset(DIL);
+  uint32_t LineOffset = FunctionSamples::getOffset(DIL);
   uint32_t Discriminator = DIL->getBaseDiscriminator();
 
   auto T = FS->findCallTargetMapAt(LineOffset, Discriminator);
@@ -678,8 +671,8 @@
   if (T)
     for (const auto &T_C : T.get())
       Sum += T_C.second;
-  if (const FunctionSamplesMap *M = FS->findFunctionSamplesMapAt(
-          LineLocation(getOffset(DIL), DIL->getBaseDiscriminator()))) {
+  if (const FunctionSamplesMap *M = FS->findFunctionSamplesMapAt(LineLocation(
+          FunctionSamples::getOffset(DIL), DIL->getBaseDiscriminator()))) {
     if (M->empty())
       return R;
     for (const auto &NameFS : *M) {
@@ -710,20 +703,7 @@
   if (!DIL)
     return Samples;
 
-  const DILocation *PrevDIL = DIL;
-  for (DIL = DIL->getInlinedAt(); DIL; DIL = DIL->getInlinedAt()) {
-    S.push_back(std::make_pair(
-        LineLocation(getOffset(DIL), DIL->getBaseDiscriminator()),
-        PrevDIL->getScope()->getSubprogram()->getLinkageName()));
-    PrevDIL = DIL;
-  }
-  if (S.size() == 0)
-    return Samples;
-  const FunctionSamples *FS = Samples;
-  for (int i = S.size() - 1; i >= 0 && FS != nullptr; i--) {
-    FS = FS->findFunctionSamplesAt(S[i].first, S[i].second);
-  }
-  return FS;
+  return Samples->findFunctionSamples(DIL);
 }
 
 bool SampleProfileLoader::inlineCallInstruction(Instruction *I) {
@@ -1281,7 +1261,7 @@
           if (!DLoc)
             continue;
           const DILocation *DIL = DLoc;
-          uint32_t LineOffset = getOffset(DIL);
+          uint32_t LineOffset = FunctionSamples::getOffset(DIL);
           uint32_t Discriminator = DIL->getBaseDiscriminator();
 
           const FunctionSamples *FS = findFunctionSamples(I);