diff --git a/dlls/d3dcompiler_42/Makefile.in b/dlls/d3dcompiler_42/Makefile.in
index 109538423df..d30aad9a73b 100644
--- a/dlls/d3dcompiler_42/Makefile.in
+++ b/dlls/d3dcompiler_42/Makefile.in
@@ -1,6 +1,24 @@
 MODULE    = d3dcompiler_42.dll
+IMPORTS   = dxguid uuid
+EXTRALIBS = -lwpp
+EXTRADEFS = -DD3D_COMPILER_VERSION=42
+PARENTSRC = ../d3dcompiler_43
 
 C_SRCS = \
-	d3dcompiler_42_main.c
+	asmparser.c \
+	blob.c \
+	bytecodewriter.c \
+	compiler.c \
+	main.c \
+	reflection.c \
+	utils.c
+
+LEX_SRCS = \
+	asmshader.l \
+	hlsl.l
+
+BISON_SRCS = \
+	asmshader.y \
+	hlsl.y
 
 RC_SRCS = version.rc
diff --git a/dlls/d3dcompiler_42/d3dcompiler_42.spec b/dlls/d3dcompiler_42/d3dcompiler_42.spec
index 84adee3084c..e5127bc4ab9 100644
--- a/dlls/d3dcompiler_42/d3dcompiler_42.spec
+++ b/dlls/d3dcompiler_42/d3dcompiler_42.spec
@@ -1,13 +1,13 @@
-@ stdcall D3DAssemble(ptr long str ptr ptr long ptr ptr) d3dcompiler_43.D3DAssemble
+@ stdcall D3DAssemble(ptr long str ptr ptr long ptr ptr)
 @ stub DebugSetMute
-@ stdcall D3DCompile(ptr long str ptr ptr str str long long ptr ptr) d3dcompiler_43.D3DCompile
-@ stdcall D3DDisassemble10Effect(ptr long ptr) d3dcompiler_43.D3DDisassemble10Effect
-@ stdcall D3DDisassemble(ptr long long ptr ptr) d3dcompiler_43.D3DDisassemble
-@ stdcall D3DGetDebugInfo(ptr long ptr) d3dcompiler_43.D3DGetDebugInfo
-@ stdcall D3DGetInputAndOutputSignatureBlob(ptr long ptr) d3dcompiler_43.D3DGetInputAndOutputSignatureBlob
-@ stdcall D3DGetInputSignatureBlob(ptr long ptr) d3dcompiler_43.D3DGetInputSignatureBlob
-@ stdcall D3DGetOutputSignatureBlob(ptr long ptr) d3dcompiler_43.D3DGetOutputSignatureBlob
-@ stdcall D3DPreprocess(ptr long str ptr ptr ptr ptr) d3dcompiler_43.D3DPreprocess
-@ stdcall D3DReflect(ptr long ptr ptr) d3dcompiler_43.D3DReflect
+@ stdcall D3DCompile(ptr long str ptr ptr str str long long ptr ptr)
+@ stub D3DDisassemble10Effect(ptr long ptr)
+@ stdcall D3DDisassemble(ptr long long ptr ptr)
+@ stdcall D3DGetDebugInfo(ptr long ptr)
+@ stdcall D3DGetInputAndOutputSignatureBlob(ptr long ptr)
+@ stdcall D3DGetInputSignatureBlob(ptr long ptr)
+@ stdcall D3DGetOutputSignatureBlob(ptr long ptr)
+@ stdcall D3DPreprocess(ptr long str ptr ptr ptr ptr)
+@ stdcall D3DReflect(ptr long ptr ptr)
 @ stub D3DReturnFailure1
-@ stdcall D3DStripShader(ptr long long ptr) d3dcompiler_43.D3DStripShader
+@ stdcall D3DStripShader(ptr long long ptr)
diff --git a/dlls/d3dcompiler_42/d3dcompiler_42_main.c b/dlls/d3dcompiler_42/d3dcompiler_42_main.c
deleted file mode 100644
index 4453ead0031..00000000000
--- a/dlls/d3dcompiler_42/d3dcompiler_42_main.c
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * Direct3D shader compiler main file
- *
- * Copyright 2010 Matteo Bruni for CodeWeavers
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
- *
- */
-
-#include "config.h"
-#include "wine/port.h"
-
-#include <stdarg.h>
-
-#include "windef.h"
-#include "winbase.h"
-
-BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
-{
-    switch (fdwReason)
-    {
-        case DLL_WINE_PREATTACH:
-            return FALSE;    /* prefer native version */
-        case DLL_PROCESS_ATTACH:
-            DisableThreadLibraryCalls(hinstDLL);
-            break;
-    }
-
-    return TRUE;
-}
diff --git a/tools/make_specfiles b/tools/make_specfiles
index 448d813c322..4fe71b00b56 100755
--- a/tools/make_specfiles
+++ b/tools/make_specfiles
@@ -111,7 +111,6 @@ my @dll_groups =
   "d3dcompiler_43",
   "d3dcompiler_47",
   "d3dcompiler_46",
-  "d3dcompiler_42",
   "d3dcompiler_41",
   "d3dcompiler_40",
   "d3dcompiler_39",