llvm-cxxfilt: filter out invalid manglings

c++filt does not attempt to demangle symbols which do not match its
expected format.  This means that the symbol must start with _Z or ___Z
(block invocation function extension).  Any other symbols are returned
as is.  Note that this is different from the behaviour of __cxa_demangle
which will demangle fragments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292467 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 3 deletions

diff --git a/tools/llvm-cxxfilt/llvm-cxxfilt.cpp b/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
index 80a54bbf63d..1e2797ba333 100644
--- a/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
+++ b/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
@@ -14,9 +14,12 @@
 
 using namespace llvm;
 
-static void demangle(llvm::raw_ostream &OS, const char *Mangled) {
+static void demangle(llvm::raw_ostream &OS, const std::string &Mangled) {
   int Status;
-  char *Demangled = itaniumDemangle(Mangled, nullptr, nullptr, &Status);
+  char *Demangled = nullptr;
+  if ((Mangled.size() >= 2 && Mangled.compare(0, 2, "_Z")) ||
+      (Mangled.size() >= 4 && Mangled.compare(0, 4, "___Z")))
+    Demangled = itaniumDemangle(Mangled.c_str(), nullptr, nullptr, &Status);
   OS << (Demangled ? Demangled : Mangled) << '\n';
   free(Demangled);
 }
@@ -24,7 +27,7 @@ static void demangle(llvm::raw_ostream &OS, const char *Mangled) {
 int main(int argc, char **argv) {
   if (argc == 1)
     for (std::string Mangled; std::getline(std::cin, Mangled);)
-      demangle(llvm::outs(), Mangled.c_str());
+      demangle(llvm::outs(), Mangled);
   else
     for (int I = 1; I < argc; ++I)
       demangle(llvm::outs(), argv[I]);