[Demangling] Remangling error handling for the OldRemangler.

First pass at adding error handling to the OldRemangler.  Still pondering
assert() calls.

rdar://79725187

Author: al45tair

include/swift/Demangling/Demangle.h

@@ -535,6 +535,8 @@ struct SWIFT_NODISCARD ManglingError {
     InvalidImplParameterConvention,
     InvalidMetatypeRepresentation,
     MultiByteRelatedEntity,
+    BadValueWitnessKind,
+    NotAContextNode,
   };
 
   Code        code;

include/swift/Demangling/TypeDecoder.h

@@ -1378,7 +1378,8 @@ return {}; // Not Implemented!
         parent = decodeMangledType(parentContext, depth + 1).getType();
         // Remove any generic arguments from the context node, producing a
         // node that references the nominal type declaration.
-        auto unspec = Demangle::getUnspecialized(node, Builder.getNodeFactory());
+        auto unspec =
+            Demangle::getUnspecialized(node, Builder.getNodeFactory());
         if (!unspec.isSuccess())
           return TypeLookupError("Failed to unspecialize type");
         declNode = unspec.result();

lib/Demangling/OldRemangler.cpp

@@ -1 +1 @@
-fatal error: too complex to remangle
+Error: unable to re-mangle $sBf32__t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_tN

test/Demangle/Inputs/bigtype-objcrt.txt

@@ -1 +1 @@
-Can't re-mangle $sBf32__t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_tN
+Error: unable to re-mangle $sBf32__t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_t_tN

test/Demangle/Inputs/bigtype-remangle.txt

@@ -32,8 +32,8 @@ extern "C" SWIFT_CC(swift) void roundTripType(const Metadata *md) {
   // Mangle that
   auto mangling = Demangle::__runtime::mangleNode(nodeTree);
   if (!mangling.isSuccess()) {
-    printf("FAIL: %s (%p) -> mangling error %d\n",
-           mdName.c_str(), md, mangling.errorCode());
+    printf("FAIL: %s (%p) -> mangling error %d\n", mdName.c_str(), md,
+           mangling.errorCode());
     return;
   }
   std::string mangledName = mangling.result();

test/TypeRoundTrip/Inputs/RoundTrip/RoundTrip.cpp

@@ -153,7 +153,7 @@ static void demangle(llvm::raw_ostream &os, llvm::StringRef name,
     } else {
       auto mangling = swift::Demangle::mangleNode(pointer);
       if (!mangling.isSuccess()) {
-        llvm::errs() << "\nError: unable to re-mangle " << name << '\n';
+        llvm::errs() << "Error: unable to re-mangle " << name << '\n';
         exit(1);
       }
       remangled = mangling.result();
@@ -168,7 +168,7 @@ static void demangle(llvm::raw_ostream &os, llvm::StringRef name,
                       remangled.substr(prefixLen);
       }
       if (name != remangled) {
-        llvm::errs() << "\nError: re-mangled name \n  " << remangled
+        llvm::errs() << "Error: re-mangled name \n  " << remangled
                      << "\ndoes not match original name\n  " << name << '\n';
         exit(1);
       }
@@ -181,7 +181,7 @@ static void demangle(llvm::raw_ostream &os, llvm::StringRef name,
     if (pointer) {
       auto mangling = swift::Demangle::mangleNodeOld(pointer);
       if (!mangling.isSuccess()) {
-        llvm::errs() << "\nError: unable to re-mangle " << name << '\n';
+        llvm::errs() << "Error: unable to re-mangle " << name << '\n';
         exit(1);
       }
       remangled = mangling.result();
@@ -192,12 +192,12 @@ static void demangle(llvm::raw_ostream &os, llvm::StringRef name,
   if (!TreeOnly) {
     if (RemangleNew) {
       if (!pointer) {
-        llvm::errs() << "Can't de-mangle " << name << '\n';
+        llvm::errs() << "Error: unable to de-mangle " << name << '\n';
         exit(1);
       }
       auto mangling = swift::Demangle::mangleNode(pointer);
       if (!mangling.isSuccess()) {
-        llvm::errs() << "Can't re-mangle " << name << '\n';
+        llvm::errs() << "Error: unable to re-mangle " << name << '\n';
         exit(1);
       }
       std::string remangled = mangling.result();
@@ -208,7 +208,7 @@ static void demangle(llvm::raw_ostream &os, llvm::StringRef name,
       stripSpecialization(pointer);
       auto mangling = swift::Demangle::mangleNode(pointer);
       if (!mangling.isSuccess()) {
-        llvm::errs() << "Can't re-mangle " << name << '\n';
+        llvm::errs() << "Error: unable to re-mangle " << name << '\n';
         exit(1);
       }
       std::string remangled = mangling.result();