mcstreamerize .no_dead_strip and .reference for static ctors/dtors.

llvm-svn: 94290

include/llvm/MC/MCAsmInfo.h

@@ -209,10 +209,9 @@ namespace llvm {
     /// .file directive, this is true for ELF targets.
     bool HasSingleParameterDotFile;          // Defaults to true.
 
-    /// UsedDirective - This directive, if non-null, is used to declare a global
-    /// as being used somehow that the assembler can't see.  This prevents dead
-    /// code elimination on some targets.
-    const char *UsedDirective;               // Defaults to NULL.
+    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
+    /// directive.
+    bool HasNoDeadStrip;                     // Defaults to false.
 
     /// WeakRefDirective - This directive, if non-null, is used to declare a
     /// global as being a weak undefined symbol.
@@ -410,15 +409,9 @@ namespace llvm {
     bool getCOMMDirectiveTakesAlignment() const {
       return COMMDirectiveTakesAlignment;
     }
-    bool hasDotTypeDotSizeDirective() const {
-      return HasDotTypeDotSizeDirective;
-    }
-    bool hasSingleParameterDotFile() const {
-      return HasSingleParameterDotFile;
-    }
-    const char *getUsedDirective() const {
-      return UsedDirective;
-    }
+    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
+    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
+    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
     const char *getWeakRefDirective() const { return WeakRefDirective; }
     const char *getWeakDefDirective() const { return WeakDefDirective; }
     const char *getLinkOnceDirective() const { return LinkOnceDirective; }

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -313,7 +313,7 @@ bool AsmPrinter::doFinalization(Module &M) {
   }
 
   if (MAI->getSetDirective()) {
-    O << '\n';
+    OutStreamer.AddBlankLine();
     for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
          I != E; ++I) {
       MCSymbol *Name = GetGlobalValueSymbol(I);
@@ -563,7 +563,7 @@ void AsmPrinter::printPICJumpTableEntry(const MachineJumpTableInfo *MJTI,
   } else {
     O << *GetMBBSymbol(MBB->getNumber());
     // If the arch uses custom Jump Table directives, don't calc relative to
-    // JT
+    // JT.
     if (!HadJTEntryDirective) 
       O << '-' << *GetJTISymbol(uid);
   }
@@ -575,7 +575,7 @@ void AsmPrinter::printPICJumpTableEntry(const MachineJumpTableInfo *MJTI,
 /// do nothing and return false.
 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
   if (GV->getName() == "llvm.used") {
-    if (MAI->getUsedDirective() != 0)    // No need to emit this at all.
+    if (MAI->hasNoDeadStrip())    // No need to emit this at all.
       EmitLLVMUsedList(GV->getInitializer());
     return true;
   }
@@ -597,8 +597,11 @@ bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
     EmitXXStructorList(GV->getInitializer());
     
     if (TM.getRelocationModel() == Reloc::Static &&
-        MAI->hasStaticCtorDtorReferenceInStaticMode())
-      O << ".reference .constructors_used\n";
+        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
+      StringRef Sym(".constructors_used");
+      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
+                                      MCStreamer::Reference);
+    }
     return true;
   } 
   
@@ -608,8 +611,11 @@ bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
     EmitXXStructorList(GV->getInitializer());
 
     if (TM.getRelocationModel() == Reloc::Static &&
-        MAI->hasStaticCtorDtorReferenceInStaticMode())
-      O << ".reference .destructors_used\n";
+        MAI->hasStaticCtorDtorReferenceInStaticMode()) {
+      StringRef Sym(".destructors_used");
+      OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
+                                      MCStreamer::Reference);
+    }
     return true;
   }
   
@@ -620,8 +626,6 @@ bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
 /// global in the specified llvm.used list for which emitUsedDirectiveFor
 /// is true, as being used with this directive.
 void AsmPrinter::EmitLLVMUsedList(Constant *List) {
-  const char *Directive = MAI->getUsedDirective();
-
   // Should be an array of 'i8*'.
   ConstantArray *InitList = dyn_cast<ConstantArray>(List);
   if (InitList == 0) return;
@@ -629,11 +633,9 @@ void AsmPrinter::EmitLLVMUsedList(Constant *List) {
   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
     const GlobalValue *GV =
       dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
-    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang)) {
-      O << Directive;
-      EmitConstantValueOnly(InitList->getOperand(i));
-      O << '\n';
-    }
+    if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
+      OutStreamer.EmitSymbolAttribute(GetGlobalValueSymbol(GV),
+                                      MCStreamer::NoDeadStrip);
   }
 }
 
@@ -1584,6 +1586,7 @@ void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
   // Print the main label for the block.
   if (MBB->pred_empty() || MBB->isOnlyReachableByFallthrough()) {
     if (VerboseAsm) {
+      // NOTE: Want this comment at start of line.
       O << MAI->getCommentString() << " BB#" << MBB->getNumber() << ':';
       if (const BasicBlock *BB = MBB->getBasicBlock())
         if (BB->hasName())

lib/CodeGen/AsmPrinter/DwarfException.cpp

@@ -245,8 +245,9 @@ void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
     // This name has no connection to the function, so it might get
     // dead-stripped when the function is not, erroneously.  Prohibit
     // dead-stripping unconditionally.
-    if (const char *UsedDirective = MAI->getUsedDirective())
-      O << UsedDirective << *EHFrameInfo.FunctionEHSym << "\n\n";
+    if (MAI->hasNoDeadStrip())
+      Asm->OutStreamer.EmitSymbolAttribute(EHFrameInfo.FunctionEHSym,
+                                           MCStreamer::NoDeadStrip);
   } else {
     O << *EHFrameInfo.FunctionEHSym << ":\n";
 
@@ -313,8 +314,9 @@ void DwarfException::EmitFDE(const FunctionEHFrameInfo &EHFrameInfo) {
     // on unused functions (calling undefined externals) being dead-stripped to
     // link correctly.  Yes, there really is.
     if (MMI->isUsedFunction(EHFrameInfo.function))
-      if (const char *UsedDirective = MAI->getUsedDirective())
-        O << UsedDirective << *EHFrameInfo.FunctionEHSym << "\n\n";
+      if (MAI->hasNoDeadStrip())
+        Asm->OutStreamer.EmitSymbolAttribute(EHFrameInfo.FunctionEHSym,
+                                             MCStreamer::NoDeadStrip);
   }
   Asm->O << '\n';
 }
@@ -982,7 +984,7 @@ void DwarfException::EndFunction() {
   EmitLabel("eh_func_end", SubprogramCount);
   EmitExceptionTable();
 
-  const MCSymbol *FunctionEHSym =
+  MCSymbol *FunctionEHSym =
     Asm->GetSymbolWithGlobalValueBase(MF->getFunction(), ".eh",
                                       Asm->MAI->is_EHSymbolPrivate());
   

lib/CodeGen/AsmPrinter/DwarfException.h

@@ -34,7 +34,7 @@ class raw_ostream;
 ///
 class DwarfException : public DwarfPrinter {
   struct FunctionEHFrameInfo {
-    const MCSymbol *FunctionEHSym;  // L_foo.eh
+    MCSymbol *FunctionEHSym;  // L_foo.eh
     unsigned Number;
     unsigned PersonalityIndex;
     bool hasCalls;
@@ -42,7 +42,7 @@ class DwarfException : public DwarfPrinter {
     std::vector<MachineMove> Moves;
     const Function *function;
 
-    FunctionEHFrameInfo(const MCSymbol *EHSym, unsigned Num, unsigned P,
+    FunctionEHFrameInfo(MCSymbol *EHSym, unsigned Num, unsigned P,
                         bool hC, bool hL,
                         const std::vector<MachineMove> &M,
                         const Function *f):

lib/MC/MCAsmInfo.cpp

@@ -57,7 +57,7 @@ MCAsmInfo::MCAsmInfo() {
   COMMDirectiveTakesAlignment = true;
   HasDotTypeDotSizeDirective = true;
   HasSingleParameterDotFile = true;
-  UsedDirective = 0;
+  HasNoDeadStrip = false;
   WeakRefDirective = 0;
   WeakDefDirective = 0;
   LinkOnceDirective = 0;

lib/MC/MCAsmInfoDarwin.cpp

@@ -39,7 +39,7 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() {
   SetDirective = "\t.set";
   ProtectedDirective = "\t.globl\t";
   HasDotTypeDotSizeDirective = false;
-  UsedDirective = "\t.no_dead_strip\t";
+  HasNoDeadStrip = true;
   // Note: Even though darwin has the .lcomm directive, it is just a synonym for
   // zerofill, so we prefer to use .zerofill.
 

lib/MC/MCMachOStreamer.cpp

@@ -234,6 +234,7 @@ void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
   case MCStreamer::Internal:
   case MCStreamer::Protected:
   case MCStreamer::Weak:
+  case MCStreamer::Local:
     assert(0 && "Invalid symbol attribute for Mach-O!");
     break;