[llvm-undname] Add support for demangling msvc's noexcept types.

Starting in C++17, MSVC introduced a new mangling for function
parameters that are themselves noexcept functions.  This patch
makes llvm-undname properly demangle them.

Patch by Zachary Henkel
Differential Revision: https://reviews.llvm.org/D55769

llvm-svn: 350656

2 files changed, 9 insertions, 3 deletions

diff --git a/llvm/lib/Demangle/MicrosoftDemangle.cpp b/llvm/lib/Demangle/MicrosoftDemangle.cpp
index cca7bf95a7e..51ffa0bff7f 100644
--- a/llvm/lib/Demangle/MicrosoftDemangle.cpp
+++ b/llvm/lib/Demangle/MicrosoftDemangle.cpp
@@ -1681,11 +1681,14 @@ TypeNode *Demangler::demangleType(StringView &MangledName,
   return Ty;
 }
 
-void Demangler::demangleThrowSpecification(StringView &MangledName) {
+bool Demangler::demangleThrowSpecification(StringView &MangledName) {
+  if (MangledName.consumeFront("_E"))
+    return true;
   if (MangledName.consumeFront('Z'))
-    return;
+    return false;
 
   Error = true;
+  return false;
 }
 
 FunctionSignatureNode *Demangler::demangleFunctionType(StringView &MangledName,
@@ -1709,7 +1712,7 @@ FunctionSignatureNode *Demangler::demangleFunctionType(StringView &MangledName,
 
   FTy->Params = demangleFunctionParameterList(MangledName);
 
-  demangleThrowSpecification(MangledName);
+  FTy->IsNoexcept = demangleThrowSpecification(MangledName);
 
   return FTy;
 }
diff --git a/llvm/lib/Demangle/MicrosoftDemangleNodes.cpp b/llvm/lib/Demangle/MicrosoftDemangleNodes.cpp
index 49518ef57d6..622f8e75e35 100644
--- a/llvm/lib/Demangle/MicrosoftDemangleNodes.cpp
+++ b/llvm/lib/Demangle/MicrosoftDemangleNodes.cpp
@@ -423,6 +423,9 @@ void FunctionSignatureNode::outputPost(OutputStream &OS,
   if (Quals & Q_Unaligned)
     OS << " __unaligned";
 
+  if (IsNoexcept)
+    OS << " noexcept";
+
   if (RefQualifier == FunctionRefQualifier::Reference)
     OS << " &";
   else if (RefQualifier == FunctionRefQualifier::RValueReference)