diff --git a/dlls/d3d10core/d3d10core_private.h b/dlls/d3d10core/d3d10core_private.h
index 4828ab692b5..3074bdb4497 100644
--- a/dlls/d3d10core/d3d10core_private.h
+++ b/dlls/d3d10core/d3d10core_private.h
@@ -63,13 +63,6 @@ static inline void read_dword(const char **ptr, DWORD *d)
 
 void skip_dword_unknown(const char **ptr, unsigned int count);
 
-static inline void read_tag(const char **ptr, DWORD *t, char t_str[5])
-{
-    read_dword(ptr, t);
-    memcpy(t_str, t, 4);
-    t_str[4] = '\0';
-}
-
 HRESULT parse_dxbc(const char *data, SIZE_T data_size,
         HRESULT (*chunk_handler)(const char *data, DWORD data_size, DWORD tag, void *ctx), void *ctx);
 
diff --git a/dlls/d3d10core/inputlayout.c b/dlls/d3d10core/inputlayout.c
index f6f50bc26a9..69d2173c01a 100644
--- a/dlls/d3d10core/inputlayout.c
+++ b/dlls/d3d10core/inputlayout.c
@@ -27,7 +27,6 @@ WINE_DEFAULT_DEBUG_CHANNEL(d3d10core);
 static HRESULT isgn_handler(const char *data, DWORD data_size, DWORD tag, void *ctx)
 {
     struct wined3d_shader_signature *is = ctx;
-    char tag_str[5];
 
     switch(tag)
     {
@@ -35,9 +34,7 @@ static HRESULT isgn_handler(const char *data, DWORD data_size, DWORD tag, void *
             return shader_parse_signature(data, data_size, is);
 
         default:
-            memcpy(tag_str, &tag, 4);
-            tag_str[4] = '\0';
-            FIXME("Unhandled chunk %s\n", tag_str);
+            FIXME("Unhandled chunk %s.\n", debugstr_an((const char *)&tag, 4));
             return S_OK;
     }
 }
diff --git a/dlls/d3d10core/shader.c b/dlls/d3d10core/shader.c
index 582d2a88010..11e080df833 100644
--- a/dlls/d3d10core/shader.c
+++ b/dlls/d3d10core/shader.c
@@ -27,7 +27,6 @@ WINE_DEFAULT_DEBUG_CHANNEL(d3d10core);
 static HRESULT shdr_handler(const char *data, DWORD data_size, DWORD tag, void *ctx)
 {
     struct d3d10_shader_info *shader_info = ctx;
-    char tag_str[5];
     HRESULT hr;
 
     switch(tag)
@@ -42,9 +41,7 @@ static HRESULT shdr_handler(const char *data, DWORD data_size, DWORD tag, void *
             break;
 
         default:
-            memcpy(tag_str, &tag, 4);
-            tag_str[4] = '\0';
-            FIXME("Unhandled chunk %s\n", tag_str);
+            FIXME("Unhandled chunk %s\n", debugstr_an((const char *)&tag, 4));
             break;
     }
 
@@ -118,8 +115,8 @@ HRESULT shader_parse_signature(const char *data, DWORD data_size, struct wined3d
 
         TRACE("semantic: %s, semantic idx: %u, sysval_semantic %#x, "
                 "type %u, register idx: %u, use_mask %#x, input_mask %#x\n",
-                e[i].semantic_name, e[i].semantic_idx, e[i].sysval_semantic, e[i].component_type,
-                e[i].register_idx, (e[i].mask >> 8) & 0xff, e[i].mask & 0xff);
+                debugstr_a(e[i].semantic_name), e[i].semantic_idx, e[i].sysval_semantic,
+                e[i].component_type, e[i].register_idx, (e[i].mask >> 8) & 0xff, e[i].mask & 0xff);
     }
 
     s->elements = e;
diff --git a/dlls/d3d10core/utils.c b/dlls/d3d10core/utils.c
index 29f1e7a7fb0..206efdfa7b8 100644
--- a/dlls/d3d10core/utils.c
+++ b/dlls/d3d10core/utils.c
@@ -365,12 +365,11 @@ HRESULT parse_dxbc(const char *data, SIZE_T data_size,
     HRESULT hr = S_OK;
     DWORD chunk_count;
     DWORD total_size;
-    char tag_str[5];
     unsigned int i;
     DWORD tag;
 
-    read_tag(&ptr, &tag, tag_str);
-    TRACE("tag: %s\n", tag_str);
+    read_dword(&ptr, &tag);
+    TRACE("tag: %s.\n", debugstr_an((const char *)&tag, 4));
 
     if (tag != TAG_DXBC)
     {