Make AsmStreamer maintain a notion of the current section, pushing it up from the

MCAsmStreamer.  Based on this, eliminate the current section from AsmPrinter.

While I'm at it, clean up the last of the horrible "switch to null section" stuff
and add an assert.  This change is in preparation for completely eliminating 
asmprinter::switchtosection.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79324 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/AsmPrinter.h

@@ -62,10 +62,6 @@ namespace llvm {
     typedef gcp_map_type::iterator gcp_iterator;
     gcp_map_type GCMetadataPrinters;
 
-    /// CurrentSection - The current section we are emitting to.  This is
-    /// controlled and used by the SwitchToSection method.
-    const MCSection *CurrentSection;
-    
     /// If ExuberantAsm is set, a pointer to the loop info for this
     /// function.
     ///
@@ -127,7 +123,7 @@ namespace llvm {
     std::string CurrentFnName;
     
     /// getCurrentSection() - Return the current section we are emitting to.
-    const MCSection *getCurrentSection() const { return CurrentSection; }
+    const MCSection *getCurrentSection() const;
     
 
     /// VerboseAsm - Emit comments in assembly output if this is true.

include/llvm/MC/MCStreamer.h

@@ -69,6 +69,9 @@ namespace llvm {
   protected:
     MCStreamer(MCContext &Ctx);
 
+    /// CurSection - This is the current section code is being emitted to, it is
+    /// kept up to date by SwitchSection.
+    const MCSection *CurSection;
   public:
     virtual ~MCStreamer();
 
@@ -78,11 +81,16 @@ namespace llvm {
     /// @{
 
     /// SwitchSection - Set the current section where code is being emitted to
-    /// @param Section.
+    /// @param Section.  This is required to update CurSection.
     ///
     /// This corresponds to assembler directives like .section, .text, etc.
     virtual void SwitchSection(const MCSection *Section) = 0;
 
+    
+    /// getCurrentSection - Return the current seciton that the streamer is
+    /// emitting code to.
+    const MCSection *getCurrentSection() const { return CurSection; }
+    
     /// EmitLabel - Emit a label for @param Symbol into the current section.
     ///
     /// This corresponds to an assembler statement such as:

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -63,7 +63,6 @@ AsmPrinter::AsmPrinter(formatted_raw_ostream &o, TargetMachine &tm,
 
     LastMI(0), LastFn(0), Counter(~0U),
     PrevDLT(0, ~0U, ~0U) {
-  CurrentSection = 0;
   DW = 0; MMI = 0;
   switch (AsmVerbose) {
   case cl::BOU_UNSET: VerboseAsm = VDef;  break;
@@ -91,19 +90,18 @@ TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
 }
 
 /// SwitchToSection - Switch to the specified section of the executable if we
-/// are not already in it!  If "NS" is null, then this causes us to exit the
-/// current section and not reenter another one.  This is generally used for
-/// asmprinter hacks.
-///
-/// FIXME: Remove support for null sections.
-///
+/// are not already in it!
 void AsmPrinter::SwitchToSection(const MCSection *NS) {
-  CurrentSection = NS;
-  // FIXME: Remove support for null sections!
-  if (NS)
-    OutStreamer.SwitchSection(NS);
+  assert(NS != 0 && "Must specify a section to switch to");
+  OutStreamer.SwitchSection(NS);
 }
 
+/// getCurrentSection() - Return the current section we are emitting to.
+const MCSection *AsmPrinter::getCurrentSection() const {
+  return OutStreamer.getCurrentSection();
+}
+
+
 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesAll();
   MachineFunctionPass::getAnalysisUsage(AU);
@@ -143,8 +141,6 @@ bool AsmPrinter::doInitialization(Module &M) {
       << '\n' << TAI->getCommentString()
       << " End of file scope inline assembly\n";
 
-  SwitchToSection(0);   // Reset back to no section to close off sections.
-  
   if (TAI->doesSupportDebugInformation() ||
       TAI->doesSupportExceptionHandling()) {
     MMI = getAnalysisIfAvailable<MachineModuleInfo>();
@@ -174,7 +170,6 @@ bool AsmPrinter::doFinalization(Module &M) {
     // to stuff that is actually used.  Note that doing so would require targets
     // to notice uses in operands (due to constant exprs etc).  This should
     // happen with the MC stuff eventually.
-    SwitchToSection(0);
 
     // Print out module-level global variables here.
     for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
@@ -776,7 +771,7 @@ void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV,
   if (TAI->getAlignmentIsInBytes()) NumBits = 1 << NumBits;
   O << TAI->getAlignDirective() << NumBits;
 
-  if (CurrentSection && CurrentSection->getKind().isText())
+  if (getCurrentSection()->getKind().isText())
     if (unsigned FillValue = TAI->getTextAlignFillValue()) {
       O << ',';
       PrintHex(FillValue);

lib/MC/MCAsmStreamer.cpp

@@ -24,12 +24,10 @@ class MCAsmStreamer : public MCStreamer {
   raw_ostream &OS;
   const TargetAsmInfo &TAI;
   AsmPrinter *Printer;
-  const MCSection *CurSection;
 public:
   MCAsmStreamer(MCContext &Context, raw_ostream &_OS, const TargetAsmInfo &tai,
                 AsmPrinter *_AsmPrinter)
-    : MCStreamer(Context), OS(_OS), TAI(tai), Printer(_AsmPrinter),
-      CurSection(0) {}
+    : MCStreamer(Context), OS(_OS), TAI(tai), Printer(_AsmPrinter) {}
   ~MCAsmStreamer() {}
 
   /// @name MCStreamer Interface

lib/MC/MCStreamer.cpp

@@ -11,7 +11,7 @@
 
 using namespace llvm;
 
-MCStreamer::MCStreamer(MCContext &_Context) : Context(_Context) {
+MCStreamer::MCStreamer(MCContext &_Context) : Context(_Context), CurSection(0) {
 }
 
 MCStreamer::~MCStreamer() {