diff --git a/clang/cmake/modules/AddClang.cmake b/clang/cmake/modules/AddClang.cmake
--- a/clang/cmake/modules/AddClang.cmake
+++ b/clang/cmake/modules/AddClang.cmake
@@ -17,7 +17,7 @@
     message(FATAL_ERROR "SOURCE source-file required by clang_tablegen")
   endif()
 
-  set( CLANG_TABLEGEN_ARGUMENTS -I ${CLANG_SOURCE_DIR}/include )
+  set( CLANG_TABLEGEN_ARGUMENTS "" )
   set( LLVM_TARGET_DEFINITIONS ${CTG_SOURCE} )
   tablegen(CLANG ${CTG_UNPARSED_ARGUMENTS} ${CLANG_TABLEGEN_ARGUMENTS})
 
diff --git a/llvm/cmake/modules/TableGen.cmake b/llvm/cmake/modules/TableGen.cmake
--- a/llvm/cmake/modules/TableGen.cmake
+++ b/llvm/cmake/modules/TableGen.cmake
@@ -2,10 +2,6 @@
 # Extra parameters for `tblgen' may come after `ofn' parameter.
 # Adds the name of the generated file to TABLEGEN_OUTPUT.
 
-if(LLVM_MAIN_INCLUDE_DIR)
-  set(LLVM_TABLEGEN_FLAGS -I ${LLVM_MAIN_INCLUDE_DIR})
-endif()
-
 function(tablegen project ofn)
   # Validate calling context.
   if(NOT ${project}_TABLEGEN_EXE)
@@ -75,6 +71,14 @@
     set(tblgen_change_flag "--write-if-changed")
   endif()
 
+  # With CMake 3.12 this can be reduced to:
+  # get_directory_property(tblgen_includes "INCLUDE_DIRECTORIES")
+  # list(TRANSFORM tblgen_includes PREPEND -I)
+  set(tblgen_includes)
+  get_directory_property(includes "INCLUDE_DIRECTORIES")
+  foreach(include ${includes})
+    list(APPEND tblgen_includes -I ${include})
+  endforeach()
   # We need both _TABLEGEN_TARGET and _TABLEGEN_EXE in the  DEPENDS list
   # (both the target and the file) to have .inc files rebuilt on
   # a tablegen change, as cmake does not propagate file-level dependencies
@@ -86,6 +90,7 @@
   # but lets us having smaller and cleaner code here.
   add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
     COMMAND ${${project}_TABLEGEN_EXE} ${ARGN} -I ${CMAKE_CURRENT_SOURCE_DIR}
+    ${tblgen_includes}
     ${LLVM_TABLEGEN_FLAGS}
     ${LLVM_TARGET_DEFINITIONS_ABSOLUTE}
     ${tblgen_change_flag}
diff --git a/mlir/cmake/modules/AddMLIR.cmake b/mlir/cmake/modules/AddMLIR.cmake
--- a/mlir/cmake/modules/AddMLIR.cmake
+++ b/mlir/cmake/modules/AddMLIR.cmake
@@ -1,5 +1,5 @@
 function(mlir_tablegen ofn)
-  tablegen(MLIR ${ARGV} "-I${MLIR_MAIN_SRC_DIR}" "-I${MLIR_INCLUDE_DIR}")
+  tablegen(MLIR ${ARGV})
   set(TABLEGEN_OUTPUT ${TABLEGEN_OUTPUT} ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
       PARENT_SCOPE)
 endfunction()
diff --git a/mlir/examples/toy/Ch3/CMakeLists.txt b/mlir/examples/toy/Ch3/CMakeLists.txt
--- a/mlir/examples/toy/Ch3/CMakeLists.txt
+++ b/mlir/examples/toy/Ch3/CMakeLists.txt
@@ -1,3 +1,4 @@
+include_directories(include)
 add_subdirectory(include)
 
 set(LLVM_LINK_COMPONENTS
@@ -5,7 +6,7 @@
   )
 
 set(LLVM_TARGET_DEFINITIONS mlir/ToyCombine.td)
-mlir_tablegen(ToyCombine.inc -gen-rewriters "-I${CMAKE_CURRENT_SOURCE_DIR}/include")
+mlir_tablegen(ToyCombine.inc -gen-rewriters)
 add_public_tablegen_target(ToyCh3CombineIncGen)
 
 add_toy_chapter(toyc-ch3
@@ -20,7 +21,6 @@
   ToyCh3CombineIncGen
   )
 
-include_directories(include/)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 include_directories(${CMAKE_CURRENT_BINARY_DIR}/include/)
 target_link_libraries(toyc-ch3
diff --git a/mlir/examples/toy/Ch4/CMakeLists.txt b/mlir/examples/toy/Ch4/CMakeLists.txt
--- a/mlir/examples/toy/Ch4/CMakeLists.txt
+++ b/mlir/examples/toy/Ch4/CMakeLists.txt
@@ -1,3 +1,4 @@
+include_directories(include)
 add_subdirectory(include)
 
 set(LLVM_LINK_COMPONENTS
@@ -5,7 +6,7 @@
   )
 
 set(LLVM_TARGET_DEFINITIONS mlir/ToyCombine.td)
-mlir_tablegen(ToyCombine.inc -gen-rewriters "-I${CMAKE_CURRENT_SOURCE_DIR}/include")
+mlir_tablegen(ToyCombine.inc -gen-rewriters)
 add_public_tablegen_target(ToyCh4CombineIncGen)
 
 add_toy_chapter(toyc-ch4
@@ -22,7 +23,6 @@
   ToyCh4CombineIncGen
   )
 
-include_directories(include/)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 include_directories(${CMAKE_CURRENT_BINARY_DIR}/include/)
 target_link_libraries(toyc-ch4
diff --git a/mlir/examples/toy/Ch4/include/toy/CMakeLists.txt b/mlir/examples/toy/Ch4/include/toy/CMakeLists.txt
--- a/mlir/examples/toy/Ch4/include/toy/CMakeLists.txt
+++ b/mlir/examples/toy/Ch4/include/toy/CMakeLists.txt
@@ -1,6 +1,6 @@
 set(LLVM_TARGET_DEFINITIONS Ops.td)
-mlir_tablegen(Ops.h.inc -gen-op-decls "-I${CMAKE_CURRENT_SOURCE_DIR}/..")
-mlir_tablegen(Ops.cpp.inc -gen-op-defs "-I${CMAKE_CURRENT_SOURCE_DIR}/..")
+mlir_tablegen(Ops.h.inc -gen-op-decls)
+mlir_tablegen(Ops.cpp.inc -gen-op-defs)
 add_public_tablegen_target(ToyCh4OpsIncGen)
 
 set(LLVM_TARGET_DEFINITIONS ShapeInferenceInterface.td)
diff --git a/mlir/examples/toy/Ch5/CMakeLists.txt b/mlir/examples/toy/Ch5/CMakeLists.txt
--- a/mlir/examples/toy/Ch5/CMakeLists.txt
+++ b/mlir/examples/toy/Ch5/CMakeLists.txt
@@ -1,3 +1,4 @@
+include_directories(include)
 add_subdirectory(include)
 
 set(LLVM_LINK_COMPONENTS
@@ -5,7 +6,7 @@
   )
 
 set(LLVM_TARGET_DEFINITIONS mlir/ToyCombine.td)
-mlir_tablegen(ToyCombine.inc -gen-rewriters "-I${CMAKE_CURRENT_SOURCE_DIR}/include")
+mlir_tablegen(ToyCombine.inc -gen-rewriters)
 add_public_tablegen_target(ToyCh5CombineIncGen)
 
 add_toy_chapter(toyc-ch5
@@ -23,7 +24,6 @@
   ToyCh5CombineIncGen
   )
 
-include_directories(include/)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 include_directories(${CMAKE_CURRENT_BINARY_DIR}/include/)
 get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
diff --git a/mlir/examples/toy/Ch5/include/toy/CMakeLists.txt b/mlir/examples/toy/Ch5/include/toy/CMakeLists.txt
--- a/mlir/examples/toy/Ch5/include/toy/CMakeLists.txt
+++ b/mlir/examples/toy/Ch5/include/toy/CMakeLists.txt
@@ -1,6 +1,6 @@
 set(LLVM_TARGET_DEFINITIONS Ops.td)
-mlir_tablegen(Ops.h.inc -gen-op-decls "-I${CMAKE_CURRENT_SOURCE_DIR}/..")
-mlir_tablegen(Ops.cpp.inc -gen-op-defs "-I${CMAKE_CURRENT_SOURCE_DIR}/..")
+mlir_tablegen(Ops.h.inc -gen-op-decls)
+mlir_tablegen(Ops.cpp.inc -gen-op-defs)
 add_public_tablegen_target(ToyCh5OpsIncGen)
 
 set(LLVM_TARGET_DEFINITIONS ShapeInferenceInterface.td)
diff --git a/mlir/examples/toy/Ch6/CMakeLists.txt b/mlir/examples/toy/Ch6/CMakeLists.txt
--- a/mlir/examples/toy/Ch6/CMakeLists.txt
+++ b/mlir/examples/toy/Ch6/CMakeLists.txt
@@ -1,3 +1,4 @@
+include_directories(include)
 add_subdirectory(include)
 
 set(LLVM_LINK_COMPONENTS
@@ -6,7 +7,7 @@
   )
 
 set(LLVM_TARGET_DEFINITIONS mlir/ToyCombine.td)
-mlir_tablegen(ToyCombine.inc -gen-rewriters "-I${CMAKE_CURRENT_SOURCE_DIR}/include")
+mlir_tablegen(ToyCombine.inc -gen-rewriters)
 add_public_tablegen_target(ToyCh6CombineIncGen)
 
 add_toy_chapter(toyc-ch6
@@ -25,7 +26,6 @@
   ToyCh6CombineIncGen
   )
 
-include_directories(include/)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 include_directories(${CMAKE_CURRENT_BINARY_DIR}/include/)
 get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
diff --git a/mlir/examples/toy/Ch6/include/toy/CMakeLists.txt b/mlir/examples/toy/Ch6/include/toy/CMakeLists.txt
--- a/mlir/examples/toy/Ch6/include/toy/CMakeLists.txt
+++ b/mlir/examples/toy/Ch6/include/toy/CMakeLists.txt
@@ -1,6 +1,6 @@
 set(LLVM_TARGET_DEFINITIONS Ops.td)
-mlir_tablegen(Ops.h.inc -gen-op-decls "-I${CMAKE_CURRENT_SOURCE_DIR}/..")
-mlir_tablegen(Ops.cpp.inc -gen-op-defs "-I${CMAKE_CURRENT_SOURCE_DIR}/..")
+mlir_tablegen(Ops.h.inc -gen-op-decls)
+mlir_tablegen(Ops.cpp.inc -gen-op-defs)
 add_public_tablegen_target(ToyCh6OpsIncGen)
 
 set(LLVM_TARGET_DEFINITIONS ShapeInferenceInterface.td)
diff --git a/mlir/examples/toy/Ch7/CMakeLists.txt b/mlir/examples/toy/Ch7/CMakeLists.txt
--- a/mlir/examples/toy/Ch7/CMakeLists.txt
+++ b/mlir/examples/toy/Ch7/CMakeLists.txt
@@ -1,3 +1,4 @@
+include_directories(include)
 add_subdirectory(include)
 
 set(LLVM_LINK_COMPONENTS
@@ -6,7 +7,7 @@
   )
 
 set(LLVM_TARGET_DEFINITIONS mlir/ToyCombine.td)
-mlir_tablegen(ToyCombine.inc -gen-rewriters "-I${CMAKE_CURRENT_SOURCE_DIR}/include")
+mlir_tablegen(ToyCombine.inc -gen-rewriters)
 add_public_tablegen_target(ToyCh7CombineIncGen)
 
 add_toy_chapter(toyc-ch7
@@ -25,7 +26,6 @@
   ToyCh7CombineIncGen
   )
 
-include_directories(include/)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 include_directories(${CMAKE_CURRENT_BINARY_DIR}/include/)
 get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
diff --git a/mlir/examples/toy/Ch7/include/toy/CMakeLists.txt b/mlir/examples/toy/Ch7/include/toy/CMakeLists.txt
--- a/mlir/examples/toy/Ch7/include/toy/CMakeLists.txt
+++ b/mlir/examples/toy/Ch7/include/toy/CMakeLists.txt
@@ -1,6 +1,6 @@
 set(LLVM_TARGET_DEFINITIONS Ops.td)
-mlir_tablegen(Ops.h.inc -gen-op-decls "-I${CMAKE_CURRENT_SOURCE_DIR}/..")
-mlir_tablegen(Ops.cpp.inc -gen-op-defs "-I${CMAKE_CURRENT_SOURCE_DIR}/..")
+mlir_tablegen(Ops.h.inc -gen-op-decls)
+mlir_tablegen(Ops.cpp.inc -gen-op-defs)
 add_public_tablegen_target(ToyCh7OpsIncGen)
 
 set(LLVM_TARGET_DEFINITIONS ShapeInferenceInterface.td)