[CMAKE] Plumb include_directories() into tablegen()

Previously, the tablegen() cmake command, which defines custom
commands for running tablegen, included several hardcoded paths.  This
becomes unwieldy as there are more users for which these paths are
insufficient.  For most targets, cmake uses include_directories() and
the INCLUDE_DIRECTORIES directory property to specify include paths.
This change picks up the INCLUDE_DIRECTORIES property and adds it
to the include path used when running tablegen.  As a side effect, this
allows us to remove several hard coded paths to tablegen that are redundant
with specified include_directories().

I haven't removed the hardcoded path to CMAKE_CURRENT_SOURCE_DIR, which
seems generically useful.  There are several users in clang which apparently
don't have the current directory as an include_directories().  This could
be considered separately.

The new version of this path uses list APPEND rather than list TRANSFORM,
in order to be compatible with cmake 3.4.3. If we update to cmake 3.12 then
we can use list TRANSFORM instead.

Differential Revision: https://reviews.llvm.org/D77156
diff --git a/clang/cmake/modules/AddClang.cmake b/clang/cmake/modules/AddClang.cmake
index 577cc11..c1bb386 100644
--- 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
index 632f69a..65e31d0 100644
--- 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
index 2adb8f2..7449f54 100644
--- 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
index 4dab5e4..ef70dcb 100644
--- 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
index 3589b10..ae30a69 100644
--- 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
index 798d0df..7f60477 100644
--- 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
index c3627cf1..ba3a88e 100644
--- 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
index aaa9328..e8bd1fc 100644
--- 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
index 5d39a9a..be797c6 100644
--- 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
index aecf11f..c6adf5a 100644
--- 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
index 760052e..9a9f335 100644
--- 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
index fa30bd2..43eb23b 100644
--- 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)