Piotr Caban : msvcrt: Fix _unDName crash when demangling class function pointer.

[Alexandre Julliard]

Module: wine
Branch: stable
Commit: 1d23985d6407746141ace4d160f94452a755ce00
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=1d23985d6407746141ace4d160f94452a755ce00

Author: Piotr Caban <piotr at codeweavers.com>
Date:   Fri Apr 30 20:50:59 2021 +0200

msvcrt: Fix _unDName crash when demangling class function pointer.

Signed-off-by: Piotr Caban <piotr at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>
(cherry picked from commit 7a1e7cbeee94756f3c474ba63b9fe9db8bddde3a)
Signed-off-by: Michael Stefaniuc <mstefani at winehq.org>

---

 dlls/msvcrt/tests/cpp.c | 2 ++
 dlls/msvcrt/undname.c   | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/dlls/msvcrt/tests/cpp.c b/dlls/msvcrt/tests/cpp.c
index 4d3a5f8d96f..5eef5bdd93c 100644
--- a/dlls/msvcrt/tests/cpp.c
+++ b/dlls/msvcrt/tests/cpp.c
@@ -1096,6 +1096,8 @@ static void test_demangle_datatype(void)
             "class CDB_GEN_BIG_ENUM_FLAG<enum CDB_WYSIWYG_BITS_ENUM,32256>",TRUE},
         { "?AV?$CDB_GEN_BIG_ENUM_FLAG at W4CDB_WYSIWYG_BITS_ENUM@@$01@@@",
             "?AV?$CDB_GEN_BIG_ENUM_FLAG at W4CDB_WYSIWYG_BITS_ENUM@@$01@@@", FALSE},
+        { "P8test@@AACXZ", "signed char (__cdecl test::*)(void)", TRUE},
+        { "P8test@@BACXZ", "signed char (__cdecl test::*)(void)const ", TRUE},
     };
     int i, num_test = ARRAY_SIZE(demangle);
 
diff --git a/dlls/msvcrt/undname.c b/dlls/msvcrt/undname.c
index 51ce1d25665..a8e2ef2bd08 100644
--- a/dlls/msvcrt/undname.c
+++ b/dlls/msvcrt/undname.c
@@ -879,7 +879,7 @@ static BOOL demangle_datatype(struct parsed_symbol* sym, struct datatype_t* ct,
                     goto done;
                 if (modifier)
                     modifier = str_printf(sym, "%s %s", modifier, ptr_modif);
-                else if(ptr_modif[0])
+                else if(ptr_modif)
                     modifier = str_printf(sym, " %s", ptr_modif);
                 if (!get_calling_convention(*sym->current++,
                             &call_conv, &exported,