llvm-cxxfilt: support `-t` to demangle types

By default c++filt demangles functions, though you can optionally pass
`-t` to have it decode types as well, behaving nearly identical to
`__cxa_demangle`.  Add support for this mode.

llvm-svn: 292576

llvm/test/tools/llvm-cxxfilt/types.test

@@ -0,0 +1,5 @@
+RUN: llvm-cxxfilt -t f i | FileCheck %s
+
+CHECK: float
+CHECK-NEXT: int
+

llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp

@@ -8,29 +8,42 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Demangle/Demangle.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstdlib>
 #include <iostream>
 
 using namespace llvm;
 
+static cl::opt<bool>
+    Types("types",
+          cl::desc("attempt to demangle types as well as function names"),
+          cl::init(false));
+static cl::alias TypesShort("t", cl::desc("alias for --types"),
+                            cl::aliasopt(Types));
+
+static cl::list<std::string>
+Decorated(cl::Positional, cl::desc("<mangled>"), cl::ZeroOrMore);
+
 static void demangle(llvm::raw_ostream &OS, const std::string &Mangled) {
   int Status;
   char *Demangled = nullptr;
-  if ((Mangled.size() >= 2 && Mangled.compare(0, 2, "_Z")) ||
+  if (Types || ((Mangled.size() >= 2 && Mangled.compare(0, 2, "_Z")) ||
-      (Mangled.size() >= 4 && Mangled.compare(0, 4, "___Z")))
+                (Mangled.size() >= 4 && Mangled.compare(0, 4, "___Z"))))
     Demangled = itaniumDemangle(Mangled.c_str(), nullptr, nullptr, &Status);
   OS << (Demangled ? Demangled : Mangled) << '\n';
   free(Demangled);
 }
 
 int main(int argc, char **argv) {
-  if (argc == 1)
+  cl::ParseCommandLineOptions(argc, argv, "llvm symbol table dumper\n");
+
+  if (Decorated.empty())
     for (std::string Mangled; std::getline(std::cin, Mangled);)
       demangle(llvm::outs(), Mangled);
   else
-    for (int I = 1; I < argc; ++I)
+    for (const auto &Symbol : Decorated)
-      demangle(llvm::outs(), argv[I]);
+      demangle(llvm::outs(), Symbol);
 
   return EXIT_SUCCESS;
 }