Add "hasSection" flag in the Summary

[mehdi_amini]

Forgot to git add the test

[mehdi_amini]

rebase

[mehdi_amini]

r267329

include/llvm/IR/ModuleSummaryIndex.h

struct GVFlags {
     ///
     /// One use is to flag values that have local linkage types and need to
     /// have module identifier appended before placing into the combined
     /// index, to disambiguate from other values with the same name.
     /// In the future this will be used to update and optimize linkage
     /// types based on global summary-based analysis.
     GlobalValue::LinkageTypes Linkage : 4;
 
+    /// Indicate if the global value is located in a specific section.
+    unsigned HasSection : 1;
+
     /// Convenience Constructors
-    explicit GVFlags(GlobalValue::LinkageTypes Linkage) : Linkage(Linkage) {}
-    GVFlags(const GlobalValue &GV) : Linkage(GV.getLinkage()) {}
+    explicit GVFlags(GlobalValue::LinkageTypes Linkage, bool HasSection)
+        : Linkage(Linkage), HasSection(HasSection) {}
+    GVFlags(const GlobalValue &GV)
+        : Linkage(GV.getLinkage()), HasSection(GV.hasSection()) {}
   };
 
 private:
   /// Kind of summary for use in dyn_cast<> et al.
   SummaryKind Kind;
 
   /// This is the hash of the name of the symbol in the original file. It is
   /// identical to the GUID for global symbols, but differs for local since the
public:
   StringRef modulePath() const { return ModulePath; }
 
   /// Get the flags for this GlobalValue (see \p struct GVFlags).
   GVFlags flags() { return Flags; }
 
   /// Return linkage type recorded for this global value.
   GlobalValue::LinkageTypes linkage() const { return Flags.Linkage; }
 
+  /// Return true if this global value is located in a specific section.
+  bool hasSection() const { return Flags.HasSection; }
+
   /// Record a reference from this global value to the global value identified
   /// by \p RefGUID.
   void addRefEdge(GlobalValue::GUID RefGUID) { RefEdgeList.push_back(RefGUID); }
 
   /// Record a reference from this global value to the global value identified
   /// by \p RefV.
   void addRefEdge(const Value *RefV) { RefEdgeList.push_back(RefV); }
 

lib/Bitcode/Reader/BitcodeReader.cpp

 
 // Decode the flags for GlobalValue in the summary
 static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
                                                             uint64_t Version) {
   // Summary were not emitted before LLVM 3.9, we don't need to upgrade Linkage
   // like getDecodedLinkage() above. Any future change to the linkage enum and
   // to getDecodedLinkage() will need to be taken into account here as above.
   auto Linkage = GlobalValue::LinkageTypes(RawFlags & 0xF); // 4 bits
-  return GlobalValueSummary::GVFlags(Linkage);
+  RawFlags = RawFlags >> 4;
+  auto HasSection = RawFlags & 0x1; // bool
+  return GlobalValueSummary::GVFlags(Linkage, HasSection);
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {
   switch (Val) {
   default: // Map unknown visibilities to default.
   case 0: return GlobalValue::DefaultVisibility;
   case 1: return GlobalValue::HiddenVisibility;
   case 2: return GlobalValue::ProtectedVisibility;

lib/Bitcode/Writer/BitcodeWriter.cpp

 
 static unsigned getEncodedLinkage(const GlobalValue &GV) {
   return getEncodedLinkage(GV.getLinkage());
 }
 
 // Decode the flags for GlobalValue in the summary
 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
   uint64_t RawFlags = 0;
-  // Emit Linkage enum.
-  RawFlags |= Flags.Linkage; // 4 bits
+
+  RawFlags |= Flags.HasSection; // bool
+
+  // Linkage don't need to be remapped at that time for the summary. Any future
+  // change to the getEncodedLinkage() function will need to be taken into
+  // account here as well.
+  RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
+
   return RawFlags;
 }
 
 static unsigned getEncodedVisibility(const GlobalValue &GV) {
   switch (GV.getVisibility()) {
   case GlobalValue::DefaultVisibility:   return 0;
   case GlobalValue::HiddenVisibility:    return 1;
   case GlobalValue::ProtectedVisibility: return 2;

test/Bitcode/thinlto-summary-section.ll

+; Check the linkage types in both the per-module and combined summaries.
+; RUN: opt -module-summary %s -o %t.o
+; RUN: llvm-bcanalyzer -dump %t.o | FileCheck %s
+; RUN: llvm-lto -thinlto -o %t2 %t.o
+; RUN: llvm-bcanalyzer -dump %t2.thinlto.bc | FileCheck %s --check-prefix=COMBINED
+
+; CHECK: <PERMODULE {{.*}} op1=16
+; COMBINED-DAG: <COMBINED {{.*}} op1=16
+define void @functionWithSection() section "some_section" {
+    ret void
+}