From 3475d3dfe84b4f72a246f0406b2b22cc78245b43 Mon Sep 17 00:00:00 2001
From: Zachary Turner <zturner@google.com>
Date: Tue, 8 Jan 2019 21:05:51 +0000
Subject: [PATCH] [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
---
 include/llvm/Demangle/MicrosoftDemangle.h     |  2 +-
 .../llvm/Demangle/MicrosoftDemangleNodes.h    |  3 +++
 lib/Demangle/MicrosoftDemangle.cpp            |  9 ++++---
 lib/Demangle/MicrosoftDemangleNodes.cpp       |  3 +++
 test/Demangle/ms-cxx17-noexcept.test          | 25 +++++++++++++++++++
 5 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 test/Demangle/ms-cxx17-noexcept.test

diff --git a/include/llvm/Demangle/MicrosoftDemangle.h b/include/llvm/Demangle/MicrosoftDemangle.h
index b186758ebe2..97b918fc945 100644
--- a/include/llvm/Demangle/MicrosoftDemangle.h
+++ b/include/llvm/Demangle/MicrosoftDemangle.h
@@ -245,7 +245,7 @@ private:
   FuncClass demangleFunctionClass(StringView &MangledName);
   CallingConv demangleCallingConvention(StringView &MangledName);
   StorageClass demangleVariableStorageClass(StringView &MangledName);
-  void demangleThrowSpecification(StringView &MangledName);
+  bool demangleThrowSpecification(StringView &MangledName);
   wchar_t demangleWcharLiteral(StringView &MangledName);
   uint8_t demangleCharLiteral(StringView &MangledName);
 
diff --git a/include/llvm/Demangle/MicrosoftDemangleNodes.h b/include/llvm/Demangle/MicrosoftDemangleNodes.h
index e4802ae314d..9e3478e9fd2 100644
--- a/include/llvm/Demangle/MicrosoftDemangleNodes.h
+++ b/include/llvm/Demangle/MicrosoftDemangleNodes.h
@@ -323,6 +323,9 @@ struct FunctionSignatureNode : public TypeNode {
 
   // Function parameters
   NodeArrayNode *Params = nullptr;
+
+  // True if the function type is noexcept
+  bool IsNoexcept = false;
 };
 
 struct IdentifierNode : public Node {
diff --git a/lib/Demangle/MicrosoftDemangle.cpp b/lib/Demangle/MicrosoftDemangle.cpp
index cca7bf95a7e..51ffa0bff7f 100644
--- a/lib/Demangle/MicrosoftDemangle.cpp
+++ b/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/lib/Demangle/MicrosoftDemangleNodes.cpp b/lib/Demangle/MicrosoftDemangleNodes.cpp
index 49518ef57d6..622f8e75e35 100644
--- a/lib/Demangle/MicrosoftDemangleNodes.cpp
+++ b/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)
diff --git a/test/Demangle/ms-cxx17-noexcept.test b/test/Demangle/ms-cxx17-noexcept.test
new file mode 100644
index 00000000000..fc60d666d52
--- /dev/null
+++ b/test/Demangle/ms-cxx17-noexcept.test
@@ -0,0 +1,25 @@
+; RUN: llvm-undname < %s | FileCheck %s
+
+; CHECK-NOT: Invalid mangled name
+
+?nochange@@YAXXZ
+; CHECK: void __cdecl nochange(void)
+
+?a@@YAXP6AHXZ@Z
+; CHECK: void __cdecl a(int (__cdecl *)(void))
+?a@@YAXP6AHX_E@Z
+; CHECK: void __cdecl a(int (__cdecl *)(void) noexcept)
+
+?b@@YAXP6AHXZ@Z
+; CHECK: void __cdecl b(int (__cdecl *)(void))
+
+?c@@YAXP6AHXZ@Z
+; CHECK: void __cdecl c(int (__cdecl *)(void))
+?c@@YAXP6AHX_E@Z
+; CHECK: void __cdecl c(int (__cdecl *)(void) noexcept)
+
+?ee@?$e@$$A6AXXZ@@EEAAXXZ
+; CHECK: private: virtual void __cdecl e<void __cdecl(void)>::ee(void)
+
+?ee@?$e@$$A6AXX_E@@EEAAXXZ
+; CHECK: private: virtual void __cdecl e<void __cdecl(void) noexcept>::ee(void)