Mangle __unaligned in Itanium ABI

__unaligned is not currently mangled in any way in the Itanium ABI. This causes
failures when using -fms-extensions and C++ in targets using Itanium ABI.

As suggested by @rsmith the simplest thing to do here is actually mangle the
qualifier as a vendor extension.

This patch also removes the change done in D31976 and updates its test to the
new reality.

This fixes
  https://bugs.llvm.org/show_bug.cgi?id=33080
  https://bugs.llvm.org/show_bug.cgi?id=33178

Differential Revision: https://reviews.llvm.org/D33398

llvm-svn: 304523

1 files changed, 16 insertions, 6 deletions

diff --git a/clang/lib/AST/ItaniumMangle.cpp b/clang/lib/AST/ItaniumMangle.cpp
index 7db0b4d8e4ff..ff55608d3b0e 100644
--- a/clang/lib/AST/ItaniumMangle.cpp
+++ b/clang/lib/AST/ItaniumMangle.cpp
@@ -1459,8 +1459,6 @@ void CXXNameMangler::mangleNestedName(const NamedDecl *ND,
     // We do not consider restrict a distinguishing attribute for overloading
     // purposes so we must not mangle it.
     MethodQuals.removeRestrict();
-    // __unaligned is not currently mangled in any way, so remove it.
-    MethodQuals.removeUnaligned();
     mangleQualifiers(MethodQuals);
     mangleRefQualifier(Method->getRefQualifier());
   }
@@ -2140,7 +2138,8 @@ CXXNameMangler::mangleOperatorName(OverloadedOperatorKind OO, unsigned Arity) {
 }
 
 void CXXNameMangler::mangleQualifiers(Qualifiers Quals) {
-  // Vendor qualifiers come first.
+  // Vendor qualifiers come first and if they are order-insensitive they must
+  // be emitted in reversed alphabetical order, see Itanium ABI 5.1.5.
 
   // Address space qualifiers start with an ordinary letter.
   if (Quals.hasAddressSpace()) {
@@ -2176,17 +2175,28 @@ void CXXNameMangler::mangleQualifiers(Qualifiers Quals) {
   }
 
   // The ARC ownership qualifiers start with underscores.
-  switch (Quals.getObjCLifetime()) {
   // Objective-C ARC Extension:
   //
   //   <type> ::= U "__strong"
   //   <type> ::= U "__weak"
   //   <type> ::= U "__autoreleasing"
+  //
+  // Note: we emit __weak first to preserve the order as
+  // required by the Itanium ABI.
+  if (Quals.getObjCLifetime() == Qualifiers::OCL_Weak)
+    mangleVendorQualifier("__weak");
+
+  // __unaligned (from -fms-extensions)
+  if (Quals.hasUnaligned())
+    mangleVendorQualifier("__unaligned");
+
+  // Remaining ARC ownership qualifiers.
+  switch (Quals.getObjCLifetime()) {
   case Qualifiers::OCL_None:
     break;
     
   case Qualifiers::OCL_Weak:
-    mangleVendorQualifier("__weak");
+    // Do nothing as we already handled this case above.
     break;
     
   case Qualifiers::OCL_Strong:
@@ -4327,7 +4337,7 @@ bool CXXNameMangler::mangleSubstitution(const NamedDecl *ND) {
 /// substitutions.
 static bool hasMangledSubstitutionQualifiers(QualType T) {
   Qualifiers Qs = T.getQualifiers();
-  return Qs.getCVRQualifiers() || Qs.hasAddressSpace();
+  return Qs.getCVRQualifiers() || Qs.hasAddressSpace() || Qs.hasUnaligned();
 }
 
 bool CXXNameMangler::mangleSubstitution(QualType T) {