[libcxxabi] r292418 - Revert r286788

[Jonathan Roelofs via cfe-commits]

Author: jroelofs
Date: Wed Jan 18 12:12:39 2017
New Revision: 292418

URL: http://llvm.org/viewvc/llvm-project?rev=292418&view=rev
Log:
Revert r286788

The Itanium ABI [1] specifies that __cxa_demangle accept either:

   1) symbol names, which start with "_Z"
   2) type manglings, which do not start with "_Z"

r286788 erroneously assumes that it should only handle symbols, so this patch
reverts it and adds a counterexample to the testcase.

1: https://mentorembedded.github.io/cxx-abi/abi.html#demangler


Reviewers: zygoloid, EricWF

Modified:
    libcxxabi/trunk/src/cxa_demangle.cpp
    libcxxabi/trunk/test/test_demangle.pass.cpp

Modified: libcxxabi/trunk/src/cxa_demangle.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/cxa_demangle.cpp?rev=292418&r1=292417&r2=292418&view=diff
==============================================================================
--- libcxxabi/trunk/src/cxa_demangle.cpp (original)
+++ libcxxabi/trunk/src/cxa_demangle.cpp Wed Jan 18 12:12:39 2017
@@ -4979,22 +4979,12 @@ __cxa_demangle(const char *mangled_name,
         return nullptr;
     }
 
-    size_t len = std::strlen(mangled_name);
-    if (len < 2 || strncmp(mangled_name, "_Z", 2))
-    {
-        if (len < 4 || strncmp(mangled_name, "___Z", 4))
-        {
-            if (status)
-                *status = invalid_mangled_name;
-            return nullptr;
-        }
-    }
-
     size_t internal_size = buf != nullptr ? *n : 0;
     arena<bs> a;
     Db db(a);
     db.template_param.emplace_back(a);
     int internal_status = success;
+    size_t len = std::strlen(mangled_name);
     demangle(mangled_name, mangled_name + len, db,
              internal_status);
     if (internal_status == success && db.fix_forward_references &&

Modified: libcxxabi/trunk/test/test_demangle.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/test/test_demangle.pass.cpp?rev=292418&r1=292417&r2=292418&view=diff
==============================================================================
--- libcxxabi/trunk/test/test_demangle.pass.cpp (original)
+++ libcxxabi/trunk/test/test_demangle.pass.cpp Wed Jan 18 12:12:39 2017
@@ -29594,6 +29594,9 @@ const char* cases[][2] =
     // NOTE: disable this test since it is a negative test case, you cannot demangle a non-mangled symbol
     // {"\x6D", nullptr}, 	// This use to crash with ASAN
     {"_ZTIU4_farrVKPi", "typeinfo for int* const volatile restrict _far"},
+
+    // mangled names can include type manglings too, which don't start with _Z:
+    {"i", "int"},
 };
 
 const unsigned N = sizeof(cases) / sizeof(cases[0]);