Stop producing func.eh symbols on Darwin.

According Nick Kledzik (http://llvm.org/bugs/show_bug.cgi?id=19430#c2):
"... mach-o no longer needs names in the __eh_frame section (and has not for
years)."

Iain Sandoe confirms it is also unnecessary for their old darwin support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211500 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCObjectFileInfo.h

@@ -33,12 +33,6 @@ protected:
   /// weak_definition of constant 0 for an omitted EH frame.
   bool SupportsWeakOmittedEHFrame;
 
-  /// IsFunctionEHFrameSymbolPrivate - This flag is set to true if the
-  /// "EH_frame" symbol for EH information should be an assembler temporary (aka
-  /// private linkage, aka an L or .L label) or false if it should be a normal
-  /// non-.globl label.  This defaults to true.
-  bool IsFunctionEHFrameSymbolPrivate;
-
   /// SupportsCompactUnwindWithoutEHFrame - True if the target object file
   /// supports emitting a compact unwind section without an associated EH frame
   /// section.
@@ -201,9 +195,6 @@ public:
   void InitMCObjectFileInfo(StringRef TT, Reloc::Model RM, CodeModel::Model CM,
                             MCContext &ctx);
 
-  bool isFunctionEHFrameSymbolPrivate() const {
-    return IsFunctionEHFrameSymbolPrivate;
-  }
   bool getSupportsWeakOmittedEHFrame() const {
     return SupportsWeakOmittedEHFrame;
   }

lib/MC/MCDwarf.cpp

@@ -1459,13 +1459,6 @@ MCSymbol *FrameEmitterImpl::EmitFDE(MCObjectStreamer &streamer,
   const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
   bool verboseAsm = streamer.isVerboseAsm();
 
-  if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
-    MCSymbol *EHSym =
-      context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
-    streamer.EmitEHSymAttributes(frame.Function, EHSym);
-    streamer.EmitLabel(EHSym);
-  }
-
   // Length
   const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
   if (verboseAsm) streamer.AddComment("FDE Length");

lib/MC/MCObjectFileInfo.cpp

@@ -41,7 +41,6 @@ static bool useCompactUnwind(const Triple &T) {
 
 void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
   // MachO
-  IsFunctionEHFrameSymbolPrivate = false;
   SupportsWeakOmittedEHFrame = false;
 
   if (T.isOSDarwin() &&
@@ -802,7 +801,6 @@ void MCObjectFileInfo::InitMCObjectFileInfo(StringRef T, Reloc::Model relocm,
   // Common.
   CommDirectiveSupportsAlignment = true;
   SupportsWeakOmittedEHFrame = true;
-  IsFunctionEHFrameSymbolPrivate = true;
   SupportsCompactUnwindWithoutEHFrame = false;
 
   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =

test/MC/MachO/eh-frame-reloc.s

@@ -24,7 +24,7 @@ _bar:
 
 // OLD64:      Relocations [
 // OLD64-NEXT:   Section __eh_frame {
-// OLD64-NEXT:     0x20 0 3 1 X86_64_RELOC_SUBTRACTOR 0 _bar.eh
+// OLD64-NEXT:     0x20 0 3 0 X86_64_RELOC_SUBTRACTOR 0
 // OLD64-NEXT:     0x20 0 3 1 X86_64_RELOC_UNSIGNED 0 _bar
 // OLD64-NEXT:   }
 // OLD64-NEXT: ]

test/MC/MachO/eh-symbols.s

@@ -1,25 +0,0 @@
-// RUN: llvm-mc -filetype=obj -triple i686-apple-darwin %s  -o - | llvm-readobj -t | FileCheck %s
-
-// Make sure that the exception handling data has the same visibility as the
-// function it's generated for.
-
-	.private_extern	_main
-	.globl	_main
-_main:
-	.cfi_startproc
-	retl
-	.cfi_endproc
-
-"_-[NSString(local) isNullOrNil]":
-	.cfi_startproc
-	retl
-	.cfi_endproc
-
-// CHECK: Name: _-[NSString(local) isNullOrNil].eh
-
-// CHECK:       Name: _main
-// CHECK-NEXT:  PrivateExtern
-
-// CHECK:       Name: _main.eh
-// CHECK-NEXT:  PrivateExtern
-