[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325747 91177308-0d34-0410-b5e6-96231b3b80d8

Author: mtrofin

include/llvm/ProfileData/SampleProf.h

@@ -383,6 +383,23 @@ class FunctionSamples {
   /// Return the function name.
   const StringRef &getName() const { return Name; }
 
+  /// Returns the line offset to the start line of the subprogram.
+  /// We assume that a single function will not exceed 65535 LOC.
+  static unsigned getOffset(const DILocation *DIL);
+
+  /// \brief Get the FunctionSamples of the inline instance where DIL originates
+  /// from.
+  ///
+  /// The FunctionSamples of the instruction (Machine or IR) associated to
+  /// \p DIL is the inlined instance in which that instruction is coming from.
+  /// We traverse the inline stack of that instruction, and match it with the
+  /// tree nodes in the profile.
+  ///
+  /// \param Inst Instruction to query.
+  ///
+  /// \returns the FunctionSamples pointer to the inlined instance.
+  const FunctionSamples *findFunctionSamples(const DILocation *DIL) const;
+
 private:
   /// Mangled name of the function.
   StringRef Name;

lib/ProfileData/SampleProf.cpp

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/ProfileData/SampleProf.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
@@ -150,6 +151,32 @@ raw_ostream &llvm::sampleprof::operator<<(raw_ostream &OS,
   return OS;
 }
 
+unsigned FunctionSamples::getOffset(const DILocation *DIL) {
+  return (DIL->getLine() - DIL->getScope()->getSubprogram()->getLine()) &
+      0xffff;
+}
+
+const FunctionSamples *
+FunctionSamples::findFunctionSamples(const DILocation *DIL) const {
+  assert(DIL);
+  SmallVector<std::pair<LineLocation, StringRef>, 10> S;
+
+  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 this;
+  const FunctionSamples *FS = this;
+  for (int i = S.size() - 1; i >= 0 && FS != nullptr; i--) {
+    FS = FS->findFunctionSamplesAt(S[i].first, S[i].second);
+  }
+  return FS;
+}
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 LLVM_DUMP_METHOD void FunctionSamples::dump() const { print(dbgs(), 0); }
 #endif

lib/Transforms/IPO/SampleProfile.cpp

@@ -217,7 +217,6 @@ class SampleProfileLoader {
   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 @@ void SampleProfileLoader::clearFunctionData() {
   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 @@ ErrorOr<uint64_t> SampleProfileLoader::getInstWeight(const Instruction &Inst) {
     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 @@ SampleProfileLoader::findCalleeFunctionSamples(const Instruction &Inst) const {
   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
@@ -670,16 +663,16 @@ SampleProfileLoader::findIndirectCallFunctionSamples(
   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);
   Sum = 0;
   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 @@ SampleProfileLoader::findFunctionSamples(const Instruction &Inst) const {
   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 @@ void SampleProfileLoader::propagateWeights(Function &F) {
           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);