Add an c++ itanium demangler to llvm.

This adds a copy of the demangler in libcxxabi.

The code also has no dependencies on anything else in LLVM. To enforce
that I added it as another library. That way a BUILD_SHARED_LIBS will
fail if anyone adds an use of StringRef for example.

The no llvm dependency combined with the fact that this has to build
on linux, OS X and Windows required a few changes to the code. In
particular:

    No constexpr.
    No alignas

On OS X at least this library has only one global symbol:
__ZN4llvm16itanium_demangleEPKcPcPmPi

My current plan is:

    Commit something like this
    Change lld to use it
    Change lldb to use it as the fallback

    Add a few #ifdefs so that exactly the same file can be used in
    libcxxabi to export abi::__cxa_demangle.

Once the fast demangler in lldb can handle any names this
implementation can be replaced with it and we will have the one true
demangler.

llvm-svn: 280732

5 files changed, 43 insertions, 17 deletions

diff --git a/llvm/tools/llvm-cxxfilt/CMakeLists.txt b/llvm/tools/llvm-cxxfilt/CMakeLists.txt
new file mode 100644
index 0000000..4d0e5b0
--- /dev/null
+++ b/llvm/tools/llvm-cxxfilt/CMakeLists.txt
@@ -0,0 +1,7 @@
+set(LLVM_LINK_COMPONENTS
+  Demangle
+  )
+
+add_llvm_tool(llvm-cxxfilt
+  llvm-cxxfilt.cpp
+  )
diff --git a/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp b/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
new file mode 100644
index 0000000..d2c1ba3
--- /dev/null
+++ b/llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
@@ -0,0 +1,29 @@
+//===-- llvm-c++filt.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 <stdio.h>
+#include <stdlib.h>
+
+using namespace llvm;
+
+int main(int argc, char **argv) {
+  for (int I = 1; I < argc; ++I) {
+    const char *Mangled = argv[I];
+    int Status;
+    char *Demangled = itaniumDemangle(Mangled, nullptr, nullptr, &Status);
+    if (Demangled)
+      printf("%s\n", Demangled);
+    else
+      printf("%s\n", Mangled);
+    free(Demangled);
+  }
+  return 0;
+}
diff --git a/llvm/tools/llvm-objdump/CMakeLists.txt b/llvm/tools/llvm-objdump/CMakeLists.txt
index 73868d8..f1239a2 100644
--- a/llvm/tools/llvm-objdump/CMakeLists.txt
+++ b/llvm/tools/llvm-objdump/CMakeLists.txt
@@ -6,6 +6,7 @@ set(LLVM_LINK_COMPONENTS
   CodeGen
   DebugInfoDWARF
   DebugInfoPDB
+  Demangle
   MC
   MCDisassembler
   Object
diff --git a/llvm/tools/llvm-objdump/LLVMBuild.txt b/llvm/tools/llvm-objdump/LLVMBuild.txt
index 4232873..3a96691 100644
--- a/llvm/tools/llvm-objdump/LLVMBuild.txt
+++ b/llvm/tools/llvm-objdump/LLVMBuild.txt
@@ -19,4 +19,4 @@
 type = Tool
 name = llvm-objdump
 parent = Tools
-required_libraries = DebugInfoDWARF MC MCDisassembler MCParser Object all-targets
+required_libraries = DebugInfoDWARF MC MCDisassembler MCParser Object all-targets Demangle
diff --git a/llvm/tools/llvm-objdump/MachODump.cpp b/llvm/tools/llvm-objdump/MachODump.cpp
index 9782659..2e7a3b2 100644
--- a/llvm/tools/llvm-objdump/MachODump.cpp
+++ b/llvm/tools/llvm-objdump/MachODump.cpp
@@ -20,6 +20,7 @@
 #include "llvm/Config/config.h"
 #include "llvm/DebugInfo/DIContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/Demangle/Demangle.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
@@ -48,10 +49,6 @@
 #include <cstring>
 #include <system_error>
 
-#if HAVE_CXXABI_H
-#include <cxxabi.h>
-#endif
-
 #ifdef HAVE_LIBXAR
 extern "C" {
 #include <xar/xar.h>
@@ -6235,11 +6232,9 @@ static const char *GuessLiteralPointer(uint64_t ReferenceValue,
 // Out type and the ReferenceName will also be set which is added as a comment
 // to the disassembled instruction.
 //
-#if HAVE_CXXABI_H
 // If the symbol name is a C++ mangled name then the demangled name is
 // returned through ReferenceName and ReferenceType is set to
 // LLVMDisassembler_ReferenceType_DeMangled_Name .
-#endif
 //
 // When this is called to get a symbol name for a branch target then the
 // ReferenceType will be LLVMDisassembler_ReferenceType_In_Branch and then
@@ -6274,21 +6269,18 @@ static const char *SymbolizerSymbolLookUp(void *DisInfo,
       method_reference(info, ReferenceType, ReferenceName);
       if (*ReferenceType != LLVMDisassembler_ReferenceType_Out_Objc_Message)
         *ReferenceType = LLVMDisassembler_ReferenceType_Out_SymbolStub;
-    } else
-#if HAVE_CXXABI_H
-        if (SymbolName != nullptr && strncmp(SymbolName, "__Z", 3) == 0) {
+    } else if (SymbolName != nullptr && strncmp(SymbolName, "__Z", 3) == 0) {
       if (info->demangled_name != nullptr)
         free(info->demangled_name);
       int status;
       info->demangled_name =
-          abi::__cxa_demangle(SymbolName + 1, nullptr, nullptr, &status);
+          itaniumDemangle(SymbolName + 1, nullptr, nullptr, &status);
       if (info->demangled_name != nullptr) {
         *ReferenceName = info->demangled_name;
         *ReferenceType = LLVMDisassembler_ReferenceType_DeMangled_Name;
       } else
         *ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
     } else
-#endif
       *ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
   } else if (*ReferenceType == LLVMDisassembler_ReferenceType_In_PCrel_Load) {
     *ReferenceName =
@@ -6377,20 +6369,17 @@ static const char *SymbolizerSymbolLookUp(void *DisInfo,
         GuessLiteralPointer(ReferenceValue, ReferencePC, ReferenceType, info);
     if (*ReferenceName == nullptr)
       *ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
-  }
-#if HAVE_CXXABI_H
-  else if (SymbolName != nullptr && strncmp(SymbolName, "__Z", 3) == 0) {
+  } else if (SymbolName != nullptr && strncmp(SymbolName, "__Z", 3) == 0) {
     if (info->demangled_name != nullptr)
       free(info->demangled_name);
     int status;
     info->demangled_name =
-        abi::__cxa_demangle(SymbolName + 1, nullptr, nullptr, &status);
+        itaniumDemangle(SymbolName + 1, nullptr, nullptr, &status);
     if (info->demangled_name != nullptr) {
       *ReferenceName = info->demangled_name;
       *ReferenceType = LLVMDisassembler_ReferenceType_DeMangled_Name;
     }
   }
-#endif
   else {
     *ReferenceName = nullptr;
     *ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;