create sections with MCSection::Create instead of Context->getOrCreateSection.

This is needed to allow polymorphic sections.

llvm-svn: 77680

llvm/include/llvm/MC/MCContext.h

@@ -42,12 +42,14 @@ namespace llvm {
     /// objects.
     BumpPtrAllocator Allocator;
 
+    friend class MCSection;
   public:
     MCContext();
     ~MCContext();
 
-    /// GetSection - Get or create a new section with the given @param Name.
-    MCSection *GetSection(const StringRef &Name);
+    /// GetSection - Look up a section with the given @param Name, returning
+    /// null if it doesn't exist.
+    MCSection *GetSection(const StringRef &Name) const;
     
     /// CreateSymbol - Create a new symbol with the specified @param Name.
     ///

llvm/include/llvm/MC/MCSection.h

@@ -25,13 +25,13 @@ namespace llvm {
   class MCSection {
     std::string Name;
   private:
-    friend class MCContext;
-    MCSection(const StringRef &_Name) : Name(_Name) {}
-    
     MCSection(const MCSection&);      // DO NOT IMPLEMENT
     void operator=(const MCSection&); // DO NOT IMPLEMENT
+    MCSection(const StringRef &_Name, MCContext &Ctx);
   public:
 
+    static MCSection *Create(const StringRef &_Name, MCContext &Ctx);
+    
     const std::string &getName() const { return Name; }
   };
 

llvm/lib/MC/MCContext.cpp

@@ -14,22 +14,29 @@
 #include "llvm/MC/MCValue.h"
 using namespace llvm;
 
-MCContext::MCContext()
-{
+MCContext::MCContext() {
 }
 
 MCContext::~MCContext() {
 }
 
-MCSection *MCContext::GetSection(const StringRef &Name) {
-  MCSection *&Entry = Sections[Name];
-  
-  if (!Entry)
-    Entry = new (*this) MCSection(Name);
-
-  return Entry;
+MCSection *MCContext::GetSection(const StringRef &Name) const {
+  StringMap<MCSection*>::const_iterator I = Sections.find(Name);
+  return I != Sections.end() ? I->second : 0;
 }
 
+
+MCSection::MCSection(const StringRef &_Name, MCContext &Ctx) : Name(_Name) {
+  MCSection *&Entry = Ctx.Sections[Name];
+  assert(Entry == 0 && "Multiple sections with the same name created");
+  Entry = this;
+}
+
+MCSection *MCSection::Create(const StringRef &Name, MCContext &Ctx) {
+  return new (Ctx) MCSection(Name, Ctx);
+}
+
+
 MCSymbol *MCContext::CreateSymbol(const StringRef &Name) {
   assert(Name[0] != '\0' && "Normal symbols cannot be unnamed!");