[SampleFDO] Add profile remapping support for profile on-demand loading used

by ExtBinary format profile

Profile on-demand loading was added for ExtBinary format profile in rL374233,
but currently profile on-demand loading doesn't work well with profile
remapping. The patch adds the support.

Suppose a function in the current module has outline instance in the profile.
The function name in the module is different from the name of the outline
instance, but remapper knows the two names are equal. When loading profile
on-demand, the outline instance has to be loaded with remapper's help.

At the same time SampleProfileReaderItaniumRemapper is changed from a proxy
of SampleProfileReader to a helper member in SampleProfileReader.

Differential Revision: https://reviews.llvm.org/D68901

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375295 91177308-0d34-0410-b5e6-96231b3b80d8

Author: wmi-11

include/llvm/ProfileData/SampleProfReader.h

@@ -235,6 +235,62 @@ class raw_ostream;
 
 namespace sampleprof {
 
+class SampleProfileReader;
+
+/// SampleProfileReaderItaniumRemapper remaps the profile data from a
+/// sample profile data reader, by applying a provided set of equivalences
+/// between components of the symbol names in the profile.
+class SampleProfileReaderItaniumRemapper {
+public:
+  SampleProfileReaderItaniumRemapper(std::unique_ptr<MemoryBuffer> B,
+                                     std::unique_ptr<SymbolRemappingReader> SRR,
+                                     SampleProfileReader &R)
+      : Buffer(std::move(B)), Remappings(std::move(SRR)), Reader(R) {
+    assert(Remappings && "Remappings cannot be nullptr");
+  }
+
+  /// Create a remapper from the given remapping file. The remapper will
+  /// be used for profile read in by Reader.
+  static ErrorOr<std::unique_ptr<SampleProfileReaderItaniumRemapper>>
+  create(const std::string Filename, SampleProfileReader &Reader,
+         LLVMContext &C);
+
+  /// Create a remapper from the given Buffer. The remapper will
+  /// be used for profile read in by Reader.
+  static ErrorOr<std::unique_ptr<SampleProfileReaderItaniumRemapper>>
+  create(std::unique_ptr<MemoryBuffer> &B, SampleProfileReader &Reader,
+         LLVMContext &C);
+
+  /// Apply remappings to the profile read by Reader.
+  void applyRemapping(LLVMContext &Ctx);
+
+  bool hasApplied() { return RemappingApplied; }
+
+  /// Insert function name into remapper.
+  void insert(StringRef FunctionName) { Remappings->insert(FunctionName); }
+
+  /// Query whether there is equivalent in the remapper which has been
+  /// inserted.
+  bool exist(StringRef FunctionName) {
+    return Remappings->lookup(FunctionName);
+  }
+
+  /// Return the samples collected for function \p F if remapper knows
+  /// it is present in SampleMap.
+  FunctionSamples *getSamplesFor(StringRef FunctionName);
+
+private:
+  // The buffer holding the content read from remapping file.
+  std::unique_ptr<MemoryBuffer> Buffer;
+  std::unique_ptr<SymbolRemappingReader> Remappings;
+  DenseMap<SymbolRemappingReader::Key, FunctionSamples *> SampleMap;
+  // The Reader the remapper is servicing.
+  SampleProfileReader &Reader;
+  // Indicate whether remapping has been applied to the profile read
+  // by Reader -- by calling applyRemapping.
+  bool RemappingApplied = false;
+};
+
 /// Sample-based profile reader.
 ///
 /// Each profile contains sample counts for all the functions
@@ -273,8 +329,17 @@ class SampleProfileReader {
   /// Read and validate the file header.
   virtual std::error_code readHeader() = 0;
 
-  /// Read sample profiles from the associated file.
-  virtual std::error_code read() = 0;
+  /// The interface to read sample profiles from the associated file.
+  std::error_code read() {
+    if (std::error_code EC = readImpl())
+      return EC;
+    if (Remapper)
+      Remapper->applyRemapping(Ctx);
+    return sampleprof_error::success;
+  }
+
+  /// The implementaion to read sample profiles from the associated file.
+  virtual std::error_code readImpl() = 0;
 
   /// Print the profile for \p FName on stream \p OS.
   void dumpFunctionProfile(StringRef FName, raw_ostream &OS = dbgs());
@@ -295,6 +360,10 @@ class SampleProfileReader {
 
   /// Return the samples collected for function \p F.
   virtual FunctionSamples *getSamplesFor(StringRef Fname) {
+    if (Remapper) {
+      if (auto FS = Remapper->getSamplesFor(Fname))
+        return FS;
+    }
     std::string FGUID;
     Fname = getRepInFormat(Fname, getFormat(), FGUID);
     auto It = Profiles.find(Fname);
@@ -313,18 +382,24 @@ class SampleProfileReader {
   }
 
   /// Create a sample profile reader appropriate to the file format.
+  /// Create a remapper underlying if RemapFilename is not empty.
   static ErrorOr<std::unique_ptr<SampleProfileReader>>
-  create(const Twine &Filename, LLVMContext &C);
+  create(const std::string Filename, LLVMContext &C,
+         const std::string RemapFilename = "");
 
   /// Create a sample profile reader from the supplied memory buffer.
+  /// Create a remapper underlying if RemapFilename is not empty.
   static ErrorOr<std::unique_ptr<SampleProfileReader>>
-  create(std::unique_ptr<MemoryBuffer> &B, LLVMContext &C);
+  create(std::unique_ptr<MemoryBuffer> &B, LLVMContext &C,
+         const std::string RemapFilename = "");
 
   /// Return the profile summary.
-  ProfileSummary &getSummary() { return *(Summary.get()); }
+  ProfileSummary &getSummary() const { return *(Summary.get()); }
+
+  MemoryBuffer *getBuffer() const { return Buffer.get(); }
 
   /// \brief Return the profile format.
-  SampleProfileFormat getFormat() { return Format; }
+  SampleProfileFormat getFormat() const { return Format; }
 
   virtual std::unique_ptr<ProfileSymbolList> getProfileSymbolList() {
     return nullptr;
@@ -361,6 +436,8 @@ class SampleProfileReader {
   /// Compute summary for this profile.
   void computeSummary();
 
+  std::unique_ptr<SampleProfileReaderItaniumRemapper> Remapper;
+
   /// \brief The format of sample.
   SampleProfileFormat Format = SPF_None;
 };
@@ -374,7 +451,7 @@ class SampleProfileReaderText : public SampleProfileReader {
   std::error_code readHeader() override { return sampleprof_error::success; }
 
   /// Read sample profiles from the associated file.
-  std::error_code read() override;
+  std::error_code readImpl() override;
 
   /// Return true if \p Buffer is in the format supported by this class.
   static bool hasFormat(const MemoryBuffer &Buffer);
@@ -390,7 +467,7 @@ class SampleProfileReaderBinary : public SampleProfileReader {
   virtual std::error_code readHeader() override;
 
   /// Read sample profiles from the associated file.
-  std::error_code read() override;
+  std::error_code readImpl() override;
 
   /// It includes all the names that have samples either in outline instance
   /// or inline instance.
@@ -512,7 +589,7 @@ class SampleProfileReaderExtBinaryBase : public SampleProfileReaderBinary {
       : SampleProfileReaderBinary(std::move(B), C, Format) {}
 
   /// Read sample profiles in extensible format from the associated file.
-  std::error_code read() override;
+  std::error_code readImpl() override;
 
   /// Get the total size of all \p Type sections.
   uint64_t getSectionSize(SecType Type);
@@ -581,7 +658,7 @@ class SampleProfileReaderCompactBinary : public SampleProfileReaderBinary {
   static bool hasFormat(const MemoryBuffer &Buffer);
 
   /// Read samples only for functions to use.
-  std::error_code read() override;
+  std::error_code readImpl() override;
 
   /// Collect functions to be used when compiling Module \p M.
   void collectFuncsFrom(const Module &M) override;
@@ -612,7 +689,7 @@ class SampleProfileReaderGCC : public SampleProfileReader {
   std::error_code readHeader() override;
 
   /// Read sample profiles from the associated file.
-  std::error_code read() override;
+  std::error_code readImpl() override;
 
   /// Return true if \p Buffer is in the format supported by this class.
   static bool hasFormat(const MemoryBuffer &Buffer);
@@ -640,44 +717,6 @@ class SampleProfileReaderGCC : public SampleProfileReader {
   static const uint32_t GCOVTagAFDOFunction = 0xac000000;
 };
 
-/// A profile data reader proxy that remaps the profile data from another
-/// sample profile data reader, by applying a provided set of equivalences
-/// between components of the symbol names in the profile.
-class SampleProfileReaderItaniumRemapper : public SampleProfileReader {
-public:
-  SampleProfileReaderItaniumRemapper(
-      std::unique_ptr<MemoryBuffer> B, LLVMContext &C,
-      std::unique_ptr<SampleProfileReader> Underlying)
-      : SampleProfileReader(std::move(B), C, Underlying->getFormat()) {
-    Profiles = std::move(Underlying->getProfiles());
-    Summary = takeSummary(*Underlying);
-    // Keep the underlying reader alive; the profile data may contain
-    // StringRefs referencing names in its name table.
-    UnderlyingReader = std::move(Underlying);
-  }
-
-  /// Create a remapped sample profile from the given remapping file and
-  /// underlying samples.
-  static ErrorOr<std::unique_ptr<SampleProfileReader>>
-  create(const Twine &Filename, LLVMContext &C,
-         std::unique_ptr<SampleProfileReader> Underlying);
-
-  /// Read and validate the file header.
-  std::error_code readHeader() override { return sampleprof_error::success; }
-
-  /// Read remapping file and apply it to the sample profile.
-  std::error_code read() override;
-
-  /// Return the samples collected for function \p F.
-  FunctionSamples *getSamplesFor(StringRef FunctionName) override;
-  using SampleProfileReader::getSamplesFor;
-
-private:
-  SymbolRemappingReader Remappings;
-  DenseMap<SymbolRemappingReader::Key, FunctionSamples*> SampleMap;
-  std::unique_ptr<SampleProfileReader> UnderlyingReader;
-};
-
 } // end namespace sampleprof
 
 } // end namespace llvm