Add __[_[_]]Z demangling to new common demangle function

This is a follow-up to r351448. It adds support for other _*Z extensions
of the Itanium demanling, to the newly available demangle function
heuristic.

Reviewed by: erik.pilkington, rupprecht, grimar

Differential Revision: https://reviews.llvm.org/D56855

llvm-svn: 351551

1 files changed, 7 insertions, 1 deletions

diff --git a/llvm/lib/Demangle/Demangle.cpp b/llvm/lib/Demangle/Demangle.cpp
index 8a37b92fc35..a2804dfc2c1 100644
--- a/llvm/lib/Demangle/Demangle.cpp
+++ b/llvm/lib/Demangle/Demangle.cpp
@@ -13,9 +13,15 @@
 
 #include "llvm/Demangle/Demangle.h"
 
+static bool isItaniumEncoding(const std::string &MangledName) {
+  size_t Pos = MangledName.find_first_not_of('_');
+  // A valid Itanium encoding requires 1-4 leading underscores, followed by 'Z'.
+  return Pos > 0 && Pos <= 4 && MangledName[Pos] == 'Z';
+}
+
 std::string llvm::demangle(const std::string &MangledName) {
   char *Demangled;
-  if (MangledName.compare(0, 2, "_Z") == 0)
+  if (isItaniumEncoding(MangledName))
     Demangled = itaniumDemangle(MangledName.c_str(), nullptr, nullptr, nullptr);
   else
     Demangled =