[ThinLTO] Rename HasSection to NoRename (NFC)

[tejohnson]

Summary

This is in preparation for a change to utilize this flag for symbols
referenced/defined in either inline or module level assembly.

[mehdi_amini]

LGTM.

Thanks for staging out all the NFC changes!

llvm/trunk/include/llvm/IR/ModuleSummaryIndex.h

 
 /// \brief Function and variable summary information to aid decisions and
 /// implementation of importing.
 class GlobalValueSummary {
 public:
   /// \brief Sububclass discriminator (for dyn_cast<> et al.)
   enum SummaryKind { AliasKind, FunctionKind, GlobalVarKind };
 
-  /// Group flags (Linkage, hasSection, isOptSize, etc.) as a bitfield.
+  /// Group flags (Linkage, noRename, isOptSize, etc.) as a bitfield.
   struct GVFlags {
     /// \brief The linkage type of the associated global value.
     ///
     /// 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.
     unsigned Linkage : 4;
 
-    /// Indicate if the global value is located in a specific section.
-    unsigned HasSection : 1;
+    /// Indicate if the global value cannot be renamed (in a specific section,
+    /// possibly referenced from inline assembly, etc).
+    unsigned NoRename : 1;
 
     /// Indicate if the function is not viable to inline.
     unsigned IsNotViableToInline : 1;
 
     /// Convenience Constructors
-    explicit GVFlags(GlobalValue::LinkageTypes Linkage, bool HasSection,
+    explicit GVFlags(GlobalValue::LinkageTypes Linkage, bool NoRename,
                      bool IsNotViableToInline)
-        : Linkage(Linkage), HasSection(HasSection),
+        : Linkage(Linkage), NoRename(NoRename),
           IsNotViableToInline(IsNotViableToInline) {}
 
     GVFlags(const GlobalValue &GV)
-        : Linkage(GV.getLinkage()), HasSection(GV.hasSection()) {
+        : Linkage(GV.getLinkage()), NoRename(GV.hasSection()) {
       IsNotViableToInline = false;
       if (const auto *F = dyn_cast<Function>(&GV))
         // Inliner doesn't handle variadic functions.
         // FIXME: refactor this to use the same code that inliner is using.
         IsNotViableToInline = F->isVarArg();
     }
   };
 
public:
   }
 
   bool isNotViableToInline() const { return Flags.IsNotViableToInline; }
 
   /// Return true if this summary is for a GlobalValue that needs promotion
   /// to be referenced from another module.
   bool needsRenaming() const { return GlobalValue::isLocalLinkage(linkage()); }
 
-  /// Return true if this global value is located in a specific section.
-  bool hasSection() const { return Flags.HasSection; }
+  /// Return true if this global value cannot be renamed (in a specific section,
+  /// possibly referenced from inline assembly, etc).
+  bool noRename() const { return Flags.NoRename; }
 
   /// 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); }

llvm/trunk/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
   RawFlags = RawFlags >> 4;
-  bool HasSection = RawFlags & 0x1;
+  bool NoRename = RawFlags & 0x1;
   bool IsNotViableToInline = RawFlags & 0x2;
-  return GlobalValueSummary::GVFlags(Linkage, HasSection, IsNotViableToInline);
+  return GlobalValueSummary::GVFlags(Linkage, NoRename, IsNotViableToInline);
 }
 
 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;

llvm/trunk/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;
 
-  RawFlags |= Flags.HasSection; // bool
+  RawFlags |= Flags.NoRename; // bool
   RawFlags |= (Flags.IsNotViableToInline << 1);
   // 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;
 }

llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp

 
 // Return true if the Summary describes a GlobalValue that can be externally
 // referenced, i.e. it does not need renaming (linkage is not local) or renaming
 // is possible (does not have a section for instance).
 static bool canBeExternallyReferenced(const GlobalValueSummary &Summary) {
   if (!Summary.needsRenaming())
     return true;
 
-  if (Summary.hasSection())
-    // Can't rename a global that needs renaming if has a section.
+  if (Summary.noRename())
+    // Can't externally reference a global that needs renaming if has a section
+    // or is referenced from inline assembly, for example.
     return false;
 
   return true;
 }
 
 // Return true if \p GUID describes a GlobalValue that can be externally
 // referenced, i.e. it does not need renaming (linkage is not local) or
 // renaming is possible (does not have a section for instance).