[PATCH 0/1] MR2932: dbghelp: Better handle very long C++ qualified identifiers in dwarf.

[eric pouech (＠epo)]

This fixes some crashes especially when dealing with very long C++ names
(like template classes).

Fortunately, dwarf internals don't require type lookup by name (eg.
on forward declaration), so the impact of thrashing some names is limited.

It's very likely native doesn't store directly these very long names
(it could either store the qualified mangled name - which can be way shorter
for template classes - or use the names in lexical hierarchy: both boil down
to storing less information, and recompute it (unmangle or class hierarchy
walk) upon request).
But this would need a proper C++ support in dbghelp. Not for today.

Signed-off-by: Eric Pouech

[PATCH 1/1] dbghelp: Better handle very long C++ qualified identifiers in dwarf.

[Eric Pouech]

From: Eric Pouech

This fixes some crashes especially when dealing with very long C++ names
(like template classes).

Fortunately, dwarf internals don't require type lookup by name (eg.
on forward declaration), so the impact of thrashing some names is limited.

It's very likely native doesn't store directly these very long names
(it could either store the qualified mangled name - which can be way shorter
for template classes - or use the names in lexical hierarchy: both boil down
to storing less information, and recompute it (unmangle or class hierarchy
walk) upon request).
But this would need a proper C++ support in dbghelp. Not for today.

Signed-off-by: Eric Pouech 
---
 dlls/dbghelp/dwarf.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/dlls/dbghelp/dwarf.c b/dlls/dbghelp/dwarf.c
index 1402ffcb941..46da2968dbb 100644
--- a/dlls/dbghelp/dwarf.c
+++ b/dlls/dbghelp/dwarf.c
@@ -1177,7 +1177,10 @@ static const char* dwarf2_get_cpp_name(dwarf2_debug_info_t* di, const char* name
     }

if (!di->unit_ctx->cpp_name)
+    {
         di->unit_ctx->cpp_name = pool_alloc(&di->unit_ctx->pool, MAX_SYM_NAME);
+        if (!di->unit_ctx->cpp_name) return name;
+    }
     last = di->unit_ctx->cpp_name + MAX_SYM_NAME - strlen(name) - 1;
     strcpy(last, name);

@@ -1194,7 +1197,11 @@ static const char* dwarf2_get_cpp_name(dwarf2_debug_info_t* di, const char* name
             {
                 size_t  len = strlen(diname.u.string);
                 last -= 2 + len;
-                if (last < di->unit_ctx->cpp_name) return NULL;
+                if (last < di->unit_ctx->cpp_name)
+                {
+                    WARN("Too long C++ qualified identifier for %s... using unqualified identifier\n", name);
+                    return name;
+                }
                 memcpy(last, diname.u.string, len);
                 last[len] = last[len + 1] = ':';
             }