[PATCH] D55685: Update Microsoft name mangling scheme for exception specifiers in the type system

[Zachary Henkel via Phabricator via cfe-commits]

zahen created this revision.
zahen added reviewers: zturner, rnk.
Herald added a subscriber: cfe-commits.

The msvc exception specifier for noexcept function types has changed from the 
prior default of "Z" to "_E" if the function cannot throw when compiling with 
/std:C++17.


Repository:
  rC Clang

https://reviews.llvm.org/D55685

Files:
  lib/AST/MicrosoftMangle.cpp
  test/CodeGenCXX/mangle-ms-exception-spec.cpp


Index: test/CodeGenCXX/mangle-ms-exception-spec.cpp
===================================================================
--- test/CodeGenCXX/mangle-ms-exception-spec.cpp
+++ test/CodeGenCXX/mangle-ms-exception-spec.cpp
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -std=c++11 -fms-extensions -emit-llvm %s -o - -triple=x86_64-pc-win32 -Wno-noexcept-type | FileCheck %s --check-prefix=CHECK --check-prefix=CXX11
+// RUN: %clang_cc1 -std=c++17 -fms-extensions -emit-llvm %s -o - -triple=x86_64-pc-win32 | FileCheck %s --check-prefix=CHECK --check-prefix=CXX17
+
+// CXX11-DAG: @"?a@@YAXP6AHXZ@Z"
+// CXX17-DAG: @"?a@@YAXP6AHX_E@Z"
+void a(int() noexcept) {}
+// CHECK-DAG: @"?b@@YAXP6AHXZ@Z"
+void b(int() noexcept(false)) {}
+// CXX11-DAG: @"?c@@YAXP6AHXZ@Z"
+// CXX17-DAG: @"?c@@YAXP6AHX_E@Z"
+void c(int() noexcept(true)) {}
+// CHECK-DAG: @"?d@@YAXP6AHXZ@Z"
+void d(int()) {}
+
+template <typename T>
+class e;
+template <typename T, typename... U>
+class e<T(U...) noexcept> {
+  // CXX11-DAG: @"?ee@?$e@$$A6AXXZ@@EEAAXXZ"
+  // CXX17-DAG: @"?ee@?$e@$$A6AXX_E@@EEAAXXZ"
+  virtual T ee(U &&...) noexcept {};
+};
+
+e<void() noexcept> e1;
+
+template <typename T>
+class f;
+template <typename T, typename... U>
+class f<T(U...)> {
+  // CHECK-DAG: @"?ff@?$f@$$A6AXXZ@@EEAAXXZ"
+  virtual T ff(U &&...) noexcept {};
+};
+
+f<void()> f1;
Index: lib/AST/MicrosoftMangle.cpp
===================================================================
--- lib/AST/MicrosoftMangle.cpp
+++ lib/AST/MicrosoftMangle.cpp
@@ -315,7 +315,8 @@
                   QualifierMangleMode QMM = QMM_Mangle);
   void mangleFunctionType(const FunctionType *T,
                           const FunctionDecl *D = nullptr,
-                          bool ForceThisQuals = false);
+                          bool ForceThisQuals = false,
+                          bool MangleExceptionSpec = true);
   void mangleNestedName(const NamedDecl *ND);
 
 private:
@@ -512,7 +513,7 @@
 
     mangleFunctionClass(FD);
 
-    mangleFunctionType(FT, FD);
+    mangleFunctionType(FT, FD, false, false);
   } else {
     Out << '9';
   }
@@ -2061,7 +2062,8 @@
 
 void MicrosoftCXXNameMangler::mangleFunctionType(const FunctionType *T,
                                                  const FunctionDecl *D,
-                                                 bool ForceThisQuals) {
+                                                 bool ForceThisQuals,
+                                                 bool MangleExceptionSpec) {
   // <function-type> ::= <this-cvr-qualifiers> <calling-convention>
   //                     <return-type> <argument-list> <throw-spec>
   const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(T);
@@ -2194,7 +2196,10 @@
       Out << '@';
   }
 
-  mangleThrowSpecification(Proto);
+    if (getASTContext().getLangOpts().CPlusPlus17 && MangleExceptionSpec)
+      mangleThrowSpecification(Proto);
+    else
+      Out << 'Z';
 }
 
 void MicrosoftCXXNameMangler::mangleFunctionClass(const FunctionDecl *FD) {
@@ -2301,13 +2306,12 @@
 }
 void MicrosoftCXXNameMangler::mangleThrowSpecification(
                                                 const FunctionProtoType *FT) {
-  // <throw-spec> ::= Z # throw(...) (default)
-  //              ::= @ # throw() or __declspec/__attribute__((nothrow))
-  //              ::= <type>+
-  // NOTE: Since the Microsoft compiler ignores throw specifications, they are
-  // all actually mangled as 'Z'. (They're ignored because their associated
-  // functionality isn't implemented, and probably never will be.)
-  Out << 'Z';
+  // <throw-spec> ::= Z # (default)
+  //              ::= _E # noexcept
+  if (FT->canThrow())
+    Out << 'Z';
+  else
+    Out << "_E";
 }
 
 void MicrosoftCXXNameMangler::mangleType(const UnresolvedUsingType *T,

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