Move demangling function from llvm-objdump to Demangle library

This allows it to be used in an upcoming llvm-readobj change.

A small change in internal behaviour of the function is to always call
the microsoftDemangle function if the string does not have an itanium
encoding prefix, rather than only if it starts with '?'. This is
harmless because the microsoftDemangle function does the same check
already.

Reviewed by: grimar, erik.pilkington

Differential Revision: https://reviews.llvm.org/D56721

llvm-svn: 351448

7 files changed, 62 insertions, 18 deletions

diff --git a/llvm/include/llvm/Demangle/Demangle.h b/llvm/include/llvm/Demangle/Demangle.h
index 4c9dc9569e1..9f3136cfcf4 100644
--- a/llvm/include/llvm/Demangle/Demangle.h
+++ b/llvm/include/llvm/Demangle/Demangle.h
@@ -11,6 +11,7 @@
 #define LLVM_DEMANGLE_DEMANGLE_H
 
 #include <cstddef>
+#include <string>
 
 namespace llvm {
 /// This is a llvm local version of __cxa_demangle. Other than the name and
@@ -36,6 +37,13 @@ enum MSDemangleFlags { MSDF_None = 0, MSDF_DumpBackrefs = 1 << 0 };
 char *microsoftDemangle(const char *mangled_name, char *buf, size_t *n,
                         int *status, MSDemangleFlags Flags = MSDF_None);
 
+/// Attempt to demangle a string using different demangling schemes.
+/// The function uses heuristics to determine which demangling scheme to use.
+/// \param MangledName - reference to string to demangle.
+/// \returns - the demangled string, or a copy of the input string if no
+/// demangling occurred.
+std::string demangle(const std::string &MangledName);
+
 /// "Partial" demangler. This supports demangling a string into an AST
 /// (typically an intermediate stage in itaniumDemangle) and querying certain
 /// properties or partially printing the demangled name.
diff --git a/llvm/lib/Demangle/CMakeLists.txt b/llvm/lib/Demangle/CMakeLists.txt
index a681af979e4..cde1a4c5c28 100644
--- a/llvm/lib/Demangle/CMakeLists.txt
+++ b/llvm/lib/Demangle/CMakeLists.txt
@@ -1,4 +1,5 @@
 add_llvm_library(LLVMDemangle
+  Demangle.cpp
   ItaniumDemangle.cpp
   MicrosoftDemangle.cpp
   MicrosoftDemangleNodes.cpp
diff --git a/llvm/lib/Demangle/Demangle.cpp b/llvm/lib/Demangle/Demangle.cpp
new file mode 100644
index 00000000000..8a37b92fc35
--- /dev/null
+++ b/llvm/lib/Demangle/Demangle.cpp
@@ -0,0 +1,30 @@
+//===-- Demangle.cpp - Common demangling functions ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file contains definitions of common demangling functions.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Demangle/Demangle.h"
+
+std::string llvm::demangle(const std::string &MangledName) {
+  char *Demangled;
+  if (MangledName.compare(0, 2, "_Z") == 0)
+    Demangled = itaniumDemangle(MangledName.c_str(), nullptr, nullptr, nullptr);
+  else
+    Demangled =
+        microsoftDemangle(MangledName.c_str(), nullptr, nullptr, nullptr);
+
+  if (!Demangled)
+    return MangledName;
+
+  std::string Ret = Demangled;
+  free(Demangled);
+  return Ret;
+}
diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 449d10cbb92..a4dbd07612f 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -463,21 +463,6 @@ bool llvm::isRelocAddressLess(RelocationRef A, RelocationRef B) {
   return A.getOffset() < B.getOffset();
 }
 
-static std::string demangle(StringRef Name) {
-  char *Demangled = nullptr;
-  if (Name.startswith("_Z"))
-    Demangled = itaniumDemangle(Name.data(), Demangled, nullptr, nullptr);
-  else if (Name.startswith("?"))
-    Demangled = microsoftDemangle(Name.data(), Demangled, nullptr, nullptr);
-
-  if (!Demangled)
-    return Name;
-
-  std::string Ret = Demangled;
-  free(Demangled);
-  return Ret;
-}
-
 template <class ELFT>
 static std::error_code getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
                                                 const RelocationRef &RelRef,
diff --git a/llvm/tools/llvm-undname/llvm-undname.cpp b/llvm/tools/llvm-undname/llvm-undname.cpp
index 60520c8f7be..5009b94352b 100644
--- a/llvm/tools/llvm-undname/llvm-undname.cpp
+++ b/llvm/tools/llvm-undname/llvm-undname.cpp
@@ -33,7 +33,7 @@ cl::opt<bool> DumpBackReferences("backrefs", cl::Optional,
 cl::list<std::string> Symbols(cl::Positional, cl::desc("<input symbols>"),
                               cl::ZeroOrMore);
 
-static void demangle(const std::string &S) {
+static void msDemangle(const std::string &S) {
   int Status;
   MSDemangleFlags Flags = MSDF_None;
   if (DumpBackReferences)
@@ -75,14 +75,14 @@ int main(int argc, char **argv) {
         outs() << Line << "\n";
         outs().flush();
       }
-      demangle(Line);
+      msDemangle(Line);
       outs() << "\n";
     }
   } else {
     for (StringRef S : Symbols) {
       outs() << S << "\n";
       outs().flush();
-      demangle(S);
+      msDemangle(S);
       outs() << "\n";
     }
   }
diff --git a/llvm/unittests/Demangle/CMakeLists.txt b/llvm/unittests/Demangle/CMakeLists.txt
index 954f3d05eac..c6291bb2a98 100644
--- a/llvm/unittests/Demangle/CMakeLists.txt
+++ b/llvm/unittests/Demangle/CMakeLists.txt
@@ -4,6 +4,7 @@ set(LLVM_LINK_COMPONENTS
 )
 
 add_llvm_unittest(DemangleTests
+  DemangleTest.cpp
   ItaniumDemangleTest.cpp
   PartialDemangleTest.cpp
 )
diff --git a/llvm/unittests/Demangle/DemangleTest.cpp b/llvm/unittests/Demangle/DemangleTest.cpp
new file mode 100644
index 00000000000..f60122cc137
--- /dev/null
+++ b/llvm/unittests/Demangle/DemangleTest.cpp
@@ -0,0 +1,19 @@
+//===-- DemangleTest.cpp --------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Demangle/Demangle.h"
+#include "gmock/gmock.h"
+
+using namespace llvm;
+
+TEST(Demangle, demangleTest) {
+  EXPECT_EQ(demangle("_Z3fooi"), "foo(int)");
+  EXPECT_EQ(demangle("?foo@@YAXH@Z"), "void __cdecl foo(int)");
+  EXPECT_EQ(demangle("foo"), "foo");
+}