Don't show private discriminators in simplified demanglings

These are really long and don't tell you anything interesting
in backtraces. They can also take up quite a bit of valuable
real estate in vertical layouts.

rdar://problem/22982415

Author: bitjammer

include/swift/Basic/Demangle.h

@@ -44,6 +44,7 @@ struct DemangleOptions {
   bool ShortenThunk = false;
   bool ShortenValueWitness = false;
   bool ShortenArchetype = false;
+  bool ShowPrivateDiscriminators = true;
 
   DemangleOptions() {}
 
@@ -62,6 +63,7 @@ struct DemangleOptions {
     Opt.ShortenThunk = true;
     Opt.ShortenValueWitness = true;
     Opt.ShortenArchetype = true;
+    Opt.ShowPrivateDiscriminators = false;
     return Opt;
   };
 };

lib/Basic/Demangle.cpp

@@ -2940,9 +2940,13 @@ void NodePrinter::print(NodePointer pointer, bool asContext, bool suppressType)
     Printer << " #" << (pointer->getChild(0)->getIndex() + 1) << ')';
     return;
   case Node::Kind::PrivateDeclName:
-    Printer << '(';
+    if (Options.ShowPrivateDiscriminators)
+      Printer << '(';
+
     print(pointer->getChild(1));
-    Printer << " in " << pointer->getChild(0)->getText() << ')';
+
+    if (Options.ShowPrivateDiscriminators)
+      Printer << " in " << pointer->getChild(0)->getText() << ')';
     return;
   case Node::Kind::Module:
     if (Options.DisplayModuleNames)

test/Demangle/Inputs/manglings.txt

@@ -214,3 +214,4 @@ _TTRXFo_iT__iT_zoPs13ErrorProtocol__XFo__dT_zoPS___ ---> reabstraction thunk hel
 _TFE1a ---> _TFE1a
 _TF21$__lldb_module_for_E0au3$E0Ps13ErrorProtocol_ ---> $__lldb_module_for_E0.$E0.unsafeMutableAddressor : Swift.ErrorProtocol
 _TMps10Comparable ---> protocol descriptor for Swift.Comparable
+_TFC4testP33_83378C430F65473055F1BD53F3ADCDB71C5doFoofT_T_ ---> test.(C in _83378C430F65473055F1BD53F3ADCDB7).doFoo () -> ()

test/Demangle/Inputs/simplified-manglings.txt

@@ -165,9 +165,9 @@ _TF8manglingX30Proprostnemluvesky_uybCEdmaEBaFT_T_ ---> Pročprostěnemluvíčes
 _TF8manglingXoi7p_qcaDcFTSiSi_Si ---> «+» infix(Int, Int) -> Int
 _TF8manglingoi2qqFTSiSi_T_ ---> ?? infix(Int, Int) -> ()
 _TFE11ext_structAV11def_structA1A4testfT_T_ ---> A.test() -> ()
-_TF13devirt_accessP5_DISC15getPrivateClassFT_CS_P5_DISC12PrivateClass ---> (getPrivateClass in _DISC)() -> (PrivateClass in _DISC)
-_TF4mainP5_mainX3wxaFT_T_ ---> (λ in _main)() -> ()
-_TF4mainP5_main3abcFT_aS_P5_DISC3xyz ---> (abc in _main)() -> (xyz in _DISC)
+_TF13devirt_accessP5_DISC15getPrivateClassFT_CS_P5_DISC12PrivateClass ---> getPrivateClass() -> PrivateClass
+_TF4mainP5_mainX3wxaFT_T_ ---> λ() -> ()
+_TF4mainP5_main3abcFT_aS_P5_DISC3xyz ---> abc() -> xyz
 _TtPMP_ ---> protocol<>.Type
 _TFCs13_NSSwiftArray29canStoreElementsOfDynamicTypefPMP_Sb ---> _NSSwiftArray.canStoreElementsOfDynamicType(protocol<>.Type) -> Bool
 _TFCs13_NSSwiftArrayg17staticElementTypePMP_ ---> _NSSwiftArray.staticElementType.getter
@@ -196,3 +196,4 @@ _TFe27mangling_generic_extensionsR_S_8RunciblerVS_3Foog1aSi ---> Foo<A where ...
 _TFe27mangling_generic_extensionsR_S_8RunciblerVS_3Foog1bx ---> Foo<A where ...>.b.getter
 _TTRXFo_iT__iT_zoPs13ErrorProtocol__XFo__dT_zoPS___ ---> thunk
 _TFE1a ---> _TFE1a
+_TFC4testP33_83378C430F65473055F1BD53F3ADCDB71C5doFoofT_T_ ---> C.doFoo() -> ()