From 76d00595ddabc82e54ea7c55c6ff0333137127ad Mon Sep 17 00:00:00 2001
From: Alexandre Ganea <alexandre.ganea@ubisoft.com>
Date: Tue, 18 Dec 2018 21:03:06 +0000
Subject: [PATCH] Fix MSVC dependency issue between Clang-tablegen and
 LLVM-tablegen

Previously, when compiling Visual Studio targets, one could see random build errors. This was caused by tablegen projects using the same build folders.
This workaround simply chains tablegen projects.

Differential Revision: https://reviews.llvm.org/D54153


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349541 91177308-0d34-0410-b5e6-96231b3b80d8
---
 cmake/modules/TableGen.cmake | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/cmake/modules/TableGen.cmake b/cmake/modules/TableGen.cmake
index d1afcb42f9d..9ac229d84f4 100644
--- a/cmake/modules/TableGen.cmake
+++ b/cmake/modules/TableGen.cmake
@@ -158,6 +158,12 @@ macro(add_tablegen target project)
       llvm_ExternalProject_BuildCmd(tblgen_build_cmd ${target}
                                     ${LLVM_NATIVE_BUILD}
                                     CONFIGURATION Release)
+      # Create an artificial dependency between tablegen projects, because they
+      # compile the same dependencies, thus using the same build folders.
+      # FIXME: A proper fix requires sequentially chaining tablegens.
+      if (NOT ${project} STREQUAL LLVM)
+        add_dependencies(${project}-tablegen-host LLVM-tablegen-host)
+      endif()
       add_custom_command(OUTPUT ${${project}_TABLEGEN_EXE}
         COMMAND ${tblgen_build_cmd}
         DEPENDS CONFIGURE_LLVM_NATIVE ${target}
-- 
2.50.1