1 files changed, 14 insertions, 68 deletions

diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
index 2959f982c43..f7bdda491cb 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
@@ -464,14 +464,13 @@ public:
   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
 
   void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
-    LastMappingSymbols[getPreviousSection().first] = std::move(LastEMSInfo);
+    // We have to keep track of the mapping symbol state of any sections we
+    // use. Each one should start off as EMS_None, which is provided as the
+    // default constructor by DenseMap::lookup.
+    LastMappingSymbols[getPreviousSection().first] = LastEMS;
+    LastEMS = LastMappingSymbols.lookup(Section);
+
     MCELFStreamer::ChangeSection(Section, Subsection);
-    auto LastMappingSymbol = LastMappingSymbols.find(Section);
-    if (LastMappingSymbol != LastMappingSymbols.end()) {
-      LastEMSInfo = std::move(LastMappingSymbol->second);
-      return;
-    }
-    LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
   }
 
   /// This function is the one used to emit instruction data into the ELF
@@ -533,14 +532,6 @@ public:
     MCELFStreamer::EmitBytes(Data);
   }
 
-  void FlushPendingMappingSymbol() {
-    if (!LastEMSInfo->hasInfo())
-      return;
-    ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
-    EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
-    EMS->resetInfo();
-  }
-
   /// This is one of the functions used to emit data into an ELF section, so the
   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
   /// necessary.
@@ -582,54 +573,22 @@ private:
     EMS_Data
   };
 
-  struct ElfMappingSymbolInfo {
-    explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
-        : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
-    void resetInfo() {
-      F = nullptr;
-      Offset = 0;
-    }
-    bool hasInfo() { return F != nullptr; }
-    SMLoc Loc;
-    MCFragment *F;
-    uint64_t Offset;
-    ElfMappingSymbol State;
-  };
-
   void EmitDataMappingSymbol() {
-    if (LastEMSInfo->State == EMS_Data)
-      return;
-    else if (LastEMSInfo->State == EMS_None) {
-      // This is a tentative symbol, it won't really be emitted until it's
-      // actually needed.
-      ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
-      auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
-      if (!DF)
-        return;
-      EMS->Loc = SMLoc();
-      EMS->F = getCurrentFragment();
-      EMS->Offset = DF->getContents().size();
-      LastEMSInfo->State = EMS_Data;
-      return;
-    }
+    if (LastEMS == EMS_Data) return;
     EmitMappingSymbol("$d");
-    LastEMSInfo->State = EMS_Data;
+    LastEMS = EMS_Data;
   }
 
   void EmitThumbMappingSymbol() {
-    if (LastEMSInfo->State == EMS_Thumb)
-      return;
-    FlushPendingMappingSymbol();
+    if (LastEMS == EMS_Thumb) return;
     EmitMappingSymbol("$t");
-    LastEMSInfo->State = EMS_Thumb;
+    LastEMS = EMS_Thumb;
   }
 
   void EmitARMMappingSymbol() {
-    if (LastEMSInfo->State == EMS_ARM)
-      return;
-    FlushPendingMappingSymbol();
+    if (LastEMS == EMS_ARM) return;
     EmitMappingSymbol("$a");
-    LastEMSInfo->State = EMS_ARM;
+    LastEMS = EMS_ARM;
   }
 
   void EmitMappingSymbol(StringRef Name) {
@@ -642,17 +601,6 @@ private:
     Symbol->setExternal(false);
   }
 
-  void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
-                         uint64_t Offset) {
-    auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
-        Name + "." + Twine(MappingSymbolCounter++)));
-    EmitLabel(Symbol, Loc, F);
-    Symbol->setType(ELF::STT_NOTYPE);
-    Symbol->setBinding(ELF::STB_LOCAL);
-    Symbol->setExternal(false);
-    Symbol->setOffset(Offset);
-  }
-
   void EmitThumbFunc(MCSymbol *Func) override {
     getAssembler().setIsThumbFunc(Func);
     EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
@@ -678,10 +626,8 @@ private:
   bool IsThumb;
   int64_t MappingSymbolCounter = 0;
 
-  DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
-      LastMappingSymbols;
-
-  std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
+  DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
+  ElfMappingSymbol LastEMS = EMS_None;
 
   // ARM Exception Handling Frame Information
   MCSymbol *ExTab;