Use internal fork of LLVM

Summary:
Place a fork of LLVM git rev c179d7b006348005d2da228aed4c3c251590baa3
under `external/llvh`(1) and modify the CMake build to use it.

I am calling it a "fork", because it is not all of LLVM. Only the parts
that are used by Hermes are included, which at this time is only parts
of `libLLVMSupporrt`. Most(2) of LLVM build scripts are removed, and it
is treated just as another ordinary library.

(1) Why `llvh`? To be able to coexist with instances of the "real" LLVM,
we must change the namespace, all public symbols containing the `llvm`
string and the include directory name. `llvh` seemed as good a name as
any. I also considered `llvm-h` and `h-llvm`, but the problem is that
they are a superstring of `llvm` so it becomes harder to search for the
`llvm` string.

Note that the actual rename will happen in a follow up diff. It would be
a massive patch.

(2) libLLVMSupport relies on pretty elaborate feature detection scripts,
which would be painful to duplicate, so for now I have preserved them
under external/llvh/cmake.

Unfortunately turning LLVM into an ordinary library is not enough, since
we were implicitly relying on a lot of functionality provided by the
LLVM build scripts. Things like setting default warning flags, easily
turning exceptions on and off, etc.

I attempted to replace it with Hermes equivalents, which are now
provided by `cmake/Hermes.cmake`:
- `add_llvm_library/tool()` is replaced by `add_hermes_library/tool()`.
- Several `LLVM_xxx` variables are replaced my similar `HERMES_xxx`
  ones.

As a result, building Hermes now requires only checking it out, and
running CMake and Ninja. It is a vastly simpler process than before.

== Limitations
- CMake LTO and ASAN builds aren't supported yet.
- The JIT requires the "real" LLVM for disassembly.

Reviewed By: avp

Differential Revision: D19658656

fbshipit-source-id: 5094d2af45e343973b1aab02c550a18b2bf93a06

API/CMakeLists.txt

@@ -3,8 +3,8 @@
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
 
-set(LLVM_REQUIRES_EH ON)
-set(LLVM_REQUIRES_RTTI ON)
+set(HERMES_ENABLE_EH ON)
+set(HERMES_ENABLE_RTTI ON)
 
 include_directories(${CMAKE_CURRENT_SOURCE_DIR})
 include_directories(${HERMES_JSI_DIR})

API/hermes/CMakeLists.txt

@@ -3,7 +3,7 @@
 # This source code is licensed under the MIT license found in the
 # LICENSE file in the root directory of this source tree.
 
-set(LLVM_OPTIONAL_SOURCES
+set(HERMES_OPTIONAL_SOURCES
   hermes.cpp
   hermes_tracing.cpp
   hermes_tracing_compat.cpp
@@ -21,7 +21,7 @@ set(api_sources
   hermes_tracing_compat.cpp
   )
 
-add_llvm_library(hermesapi
+add_hermes_library(hermesapi
         ${api_sources}
         LINK_LIBS jsi hermesVMRuntime)
 
@@ -38,22 +38,19 @@ set_property(TARGET hermesapi APPEND_STRING PROPERTY
 set_property(TARGET hermesapi APPEND_STRING PROPERTY
   COMPILE_DEFINITIONS "JSI_CREATE_SHARED_LIBRARY")
 
-set(LLVM_LINK_COMPONENTS
-  Core
-  Support
-  )
+set(HERMES_LINK_COMPONENTS LLVHSupport)
 
 # Disable EH and RTTI for compileJS
-set(LLVM_REQUIRES_EH OFF)
-set(LLVM_REQUIRES_RTTI OFF)
+set(HERMES_ENABLE_EH OFF)
+set(HERMES_ENABLE_RTTI OFF)
 
-add_llvm_library(compileJS STATIC CompileJS.cpp)
+add_hermes_library(compileJS STATIC CompileJS.cpp)
 
 # Restore EH and RTTI (Note: At the time of writing, there is no usage of
-# add_llvm_library either after this line in this file or in a sub directory.
+# add_hermes_library either after this line in this file or in a sub directory.
 # However, the values are restored anyways for the sake of sanity.)
-set(LLVM_REQUIRES_EH ON)
-set(LLVM_REQUIRES_RTTI ON)
+set(HERMES_ENABLE_EH ON)
+set(HERMES_ENABLE_RTTI ON)
 
 add_library(libhermes SHARED ${api_sources})
 target_link_libraries(libhermes

API/hermes/synthtest/CMakeLists.txt

@@ -5,6 +5,6 @@
 
 # Dummy CMakeLists to avoid a test failure
 
-add_llvm_library(synth_test
+add_hermes_library(synth_test
         Driver.cpp
         )

CMakeLists.txt

@@ -17,19 +17,53 @@ if (POLICY CMP0048)
   cmake_policy(SET CMP0048 NEW)
 endif()
 
+# find_package uses <PackageName>_ROOT variables.
+if (POLICY CMP0074)
+  cmake_policy(SET CMP0074 NEW)
+endif()
 # Include file check macros honor CMAKE_REQUIRED_LIBRARIES.
 if (POLICY CMP0075)
   cmake_policy(SET CMP0075 NEW)
 endif()
 
+# Only interpret if() arguments as variables or keywords when unquoted.
+# CMake emits a warning if this is not set.
+if (POLICY CMP0054)
+  cmake_policy(SET CMP0054 NEW)
+endif()
+
+# Pick up a workaround for a CMake problem from LLVM r282552.
+if(POLICY CMP0057)
+  cmake_policy(SET CMP0057 NEW)
+endif()
+
+# Enable transitive library dependencies
+if(POLICY CMP0022)
+  cmake_policy(SET CMP0022 NEW)
+endif()
+
+# Don't complain about mixing plain and keyword target_link_libraries commands.
+# Keyword style is when you specify whether library symbols are re-exported,
+# e.g. target_link_libraries(target PRIVATE lib).
+# LLVM currently uses plain-style target_link_libraries calls so we must
+# allow mixing.
+if (POLICY CMP0023)
+  cmake_policy(SET CMP0023 OLD)
+endif()
+
+
 # This must be consistent with the release_version in
 # android/build.gradle and npm/package.json
 project(Hermes
         VERSION 0.4.0
         LANGUAGES C CXX)
 
-include(CheckCXXCompilerFlag)
-include(CheckCXXSourceCompiles)
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules/")
+
+set(LLVH_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/external/llvh)
+
+include(Hermes)
+include(Lit)
 
 set(HERMES_RELEASE_VERSION ${PROJECT_VERSION})
 
@@ -126,11 +160,7 @@ set(ANDROID_LINUX_PERF_PATH ""
 set(HERMES_MSVC_MP ON CACHE STRING
   "Enable /MP in MSVC for parallel builds")
 
-# On Android we need an ABI specific version of LLVM.
-# Unfortunately, the build system doesn't allow setting the
-# LLVM_BUILD_DIR per ABI, so we do it here instead.
 if (HERMES_IS_ANDROID)
-  set(LLVM_BUILD_DIR "${LLVM_BUILD_BASE}-${ANDROID_ABI}")
   add_definitions(-DHERMES_PLATFORM_UNICODE=HERMES_PLATFORM_UNICODE_JAVA)
 
   # The toolchain passes -Wa,--noexecstack which is valid for compiling
@@ -151,15 +181,6 @@ if (HERMES_IS_ANDROID)
   endif()
 endif()
 
-# The hermes project is built using CMake and the LLVM's build system.
-# It expects LLVM_SRC_DIR and LLVM_BUILD_DIR to be set. For example:
-#
-# cmake -G Ninja -DLLVM_BUILD_DIR=$XXX -DLLVM_SRC_DIR=$YYY
-#
-file(TO_CMAKE_PATH "${LLVM_BUILD_DIR}" LLVM_BUILD_DIR)
-file(TO_CMAKE_PATH "${LLVM_SRC_DIR}" LLVM_SRC_DIR)
-list(APPEND CMAKE_MODULE_PATH "${LLVM_BUILD_DIR}/lib/cmake/llvm/")
-
 # Enable debug mode by default
 if ((NOT GENERATOR_IS_MULTI_CONFIG) AND CMAKE_BUILD_TYPE STREQUAL "")
     set(CMAKE_BUILD_TYPE Debug)
@@ -256,49 +277,16 @@ if (NOT (ANDROID_LINUX_PERF_PATH STREQUAL ""))
   add_definitions(-DANDROID_LINUX_PERF_PATH="${ANDROID_LINUX_PERF_PATH}")
 endif()
 
-# Build the hermes compiler by default.
-set(LLVM_BUILD_TOOLS ON)
-# Enable warnings.
-set(LLVM_ENABLE_WARNINGS ON)
-
-# Only interpret if() arguments as variables or keywords when unquoted.
-# CMake emits a warning if this is not set.
-if (POLICY CMP0054)
-  cmake_policy(SET CMP0054 NEW)
-endif()
-
 if (HERMES_ENABLE_WERROR)
-  # Turn all warnings into errors on some compilers:
-  if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
-    set(LLVM_ENABLE_WERROR ON)
-  elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU")
-    set(LLVM_ENABLE_WERROR ON)
-  elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "MSVC")
-    # Warn.
+  # Turn all warnings into errors on GCC-compatible compilers.
+  if (GCC_COMPATIBLE)
+    append("-Werror" CMAKE_CXX_FLAGS CMAKE_C_FLAGS)
   endif()
 endif()
 
 # Collect all header files and add them to the IDE.
 file(GLOB_RECURSE ALL_HEADER_FILES "*.h")
 
-# Pick up a workaround for a CMake problem from LLVM r282552.
-if(POLICY CMP0057)
-  cmake_policy(SET CMP0057 NEW)
-endif()
-# Enable transitive library dependencies
-if(POLICY CMP0022)
-    cmake_policy(SET CMP0022 NEW)
-endif()
-
-# Don't complain about mixing plain and keyword target_link_libraries commands.
-# Keyword style is when you specify whether library symbols are re-exported,
-# e.g. target_link_libraries(target PRIVATE lib).
-# LLVM currently uses plain-style target_link_libraries calls so we must
-# allow mixing.
-if (POLICY CMP0023)
-  cmake_policy(SET CMP0023 OLD)
-endif()
-
 if(HERMES_SLOW_DEBUG)
   # Enable HERMES_SLOW_DEBUG in Debug mode
   set_property(DIRECTORY APPEND PROPERTY
@@ -315,17 +303,13 @@ if (NOT (GENERATOR_IS_MULTI_CONFIG OR CMAKE_BUILD_TYPE STREQUAL Debug OR CMAKE_C
     # Enable LTO if we are not multi config generator and not a DEBUG build
     # and not GCC
     # GCC currently fails to link Hermes with LTO (see t16557748)
-    option(LLVM_ENABLE_LTO "Build Hermes with LTO" ON)
+    option(HERMES_ENABLE_LTO "Build Hermes with LTO" ON)
 endif()
 
-if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" OR
-    "${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU")
-  # Supress warnings about unknown warnings
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unknown-warning-option")
-  # Suppress an uninteresting warning about C++17 name mangling changes.
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-noexcept-type")
+if (GCC_COMPATIBLE)
   # Suppress uninteresting warnings about initializing ArrayRef from initializer lists.
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-init-list-lifetime")
+  check_cxx_compiler_flag("-Winit-list-lifetime" INIT_LIST_LIFETIME_FLAG)
+  append_if(INIT_LIST_LIFETIME_FLAG "-Wno-init-list-lifetime" CMAKE_CXX_FLAGS)
   # Don't export symbols unless we explicitly say so
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden")
 elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "MSVC")
@@ -335,6 +319,8 @@ elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "MSVC")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -wd4200")
   # C4201 nonstandard extension used: nameless struct/union
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -wd4201")
+  # C4530 C++ exception handler used, but unwind semantics are not enabled
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -wd4530")
   # Parallelize build
   if (HERMES_MSVC_MP)
     add_definitions( /MP )
@@ -345,17 +331,6 @@ endif()
 # to analyze the source code of the project.
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
-set(LLVM_MAIN_SRC_DIR ${LLVM_SRC_DIR})
-include(LLVMConfig)
-include(AddLLVM)
-include(HandleLLVMOptions)
-
-include_directories("${LLVM_SRC_DIR}/include"
-                    "${LLVM_BUILD_DIR}/include")
-
-link_directories("${LLVM_SRC_DIR}/lib"
-                 "${LLVM_BUILD_DIR}/${CMAKE_CFG_INTDIR}/lib")
-
 # Attempt to use system ICU first, if none specified.
 # Don't need ICU on Apple systems.
 if (APPLE)
@@ -374,7 +349,7 @@ if (NOT ICU_FOUND)
 
   # FindICU uses ICU_ROOT variable as a hint
   # Include 'uc' twice for static libraries that depend on each other.
-  find_package(ICU 52 COMPONENTS uc i18n data uc)
+  find_global_package(ICU 52 COMPONENTS uc i18n data uc)
 
   if (ICU_FOUND)
     foreach(LIB_FILE ${ICU_LIBRARIES})
@@ -431,9 +406,9 @@ else()
   set(CORE_FOUNDATION "")
 endif()
 
-if (CMAKE_SYSTEM_NAME STREQUAL Darwin AND NOT LLVM_BUILD_32_BITS)
+if (CMAKE_SYSTEM_NAME STREQUAL Darwin AND NOT HERMES_BUILD_32_BITS)
   set(LIBFLOWPARSER ${CMAKE_CURRENT_SOURCE_DIR}/external/flowparser/libflowparser-mac.a)
-elseif (CMAKE_SYSTEM_NAME STREQUAL Linux AND NOT LLVM_BUILD_32_BITS)
+elseif (CMAKE_SYSTEM_NAME STREQUAL Linux AND NOT HERMES_BUILD_32_BITS)
   set(LIBFLOWPARSER ${CMAKE_CURRENT_SOURCE_DIR}/external/flowparser/libflowparser-linux.a)
 else()
   set(LIBFLOWPARSER "")
@@ -453,14 +428,6 @@ set(CMAKE_XCODE_ATTRIBUTE_CLANG_CXX_LANGUAGE_STANDARD "c++11")
 set(HERMES_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(HERMES_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
-# Tell LLVM where to place the compiled binaries.
-#
-# NOTE: LLVM also uses this variable to find its own binaries, which can create
-# problems. For now the only LLVM tool we need is llvm-lit, so our short term
-# solution is to just hack that special case (the long term solution would be
-# to stop using add_llvm_tool() for our own tools).
-set(LLVM_RUNTIME_OUTPUT_INTDIR ${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
-
 if(EXISTS ${HERMES_SOURCE_DIR}/API/jsi)
   set(HERMES_JSI_DIR ${HERMES_SOURCE_DIR}/API/jsi)
 elseif(EXISTS ${FBSOURCE_DIR}/xplat/jsi)
@@ -471,6 +438,12 @@ else()
   message(FATAL_ERROR "Unable to find jsi.")
 endif()
 
+include_directories(
+  external/llvh/include
+  external/llvh/gen/include
+  ${CMAKE_CURRENT_BINARY_DIR}/external/llvh/include
+)
+
 include_directories(BEFORE
   ${CMAKE_CURRENT_BINARY_DIR}/include
   ${CMAKE_CURRENT_SOURCE_DIR}/include
@@ -485,7 +458,7 @@ if(HERMES_IS_ANDROID)
   elseif(EXISTS ${FBSOURCE_DIR}/fbandroid/libraries/fbjni/cxx)
     set(FBJNI_PATH ${FBSOURCE_DIR}/fbandroid/libraries/fbjni)
   elseif(EXISTS ${HERMES_SOURCE_DIR}/../../fbandroid/libraries/fbjni/cxx)
-    set(FBJNI_PATH ${HERMES_SOURCE_DIR}/../../fbandroid/libraries/fbjni/cxx)
+    set(FBJNI_PATH ${HERMES_SOURCE_DIR}/../../fbandroid/libraries/fbjni)
   else()
     message(FATAL_ERROR "Unable to find fbjni.")
   endif()
@@ -496,14 +469,25 @@ if(HERMES_IS_ANDROID)
   set(OPTIONAL_JNI_ONLOAD "-Wl,--undefined=JNI_OnLoad")
 endif()
 
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
+add_subdirectory(external/llvh)
+add_subdirectory(utils/hermes-lit)
 add_subdirectory(tools)
 add_subdirectory(include)
 add_subdirectory(lib)
 add_subdirectory(external)
 add_subdirectory(unittests)
-add_subdirectory(${HERMES_JSI_DIR}/jsi ${CMAKE_CURRENT_BINARY_DIR}/jsi)
 add_subdirectory(API)
 
+# Make sure JSI is compiled with PIC
+set(save_CMAKE_POSITION_INDEPENDENT_CODE ${CMAKE_POSITION_INDEPENDENT_CODE})
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+add_subdirectory(${HERMES_JSI_DIR}/jsi ${CMAKE_CURRENT_BINARY_DIR}/jsi)
+set(CMAKE_POSITION_INDEPENDENT_CODE ${save_CMAKE_POSITION_INDEPENDENT_CODE})
+
 if (EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/facebook)
     add_subdirectory(facebook)
 endif()
@@ -522,7 +506,6 @@ list(APPEND HERMES_TEST_DEPS
   hbc-attribute
   hbc-deltaprep
   hbc-diff
-  llvm-config
   )
 
 set(HERMES_LIT_TEST_PARAMS
@@ -532,15 +515,15 @@ set(HERMES_LIT_TEST_PARAMS
   use_flowparser=${HERMES_USE_FLOWPARSER}
   jit_enabled=${HERMESVM_JIT}
   jit_disassembler_enabled=${HERMESVM_JIT_DISASSEMBLER}
-  hbc_deltaprep=${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/hbc-deltaprep
-  FileCheck=${LLVM_BUILD_DIR}/${CMAKE_CFG_INTDIR}/bin/FileCheck
-  hermes=${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/hermes
-  hermesc=${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/hermesc
-  hdb=${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/hdb
-  hbcdump=${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/hbcdump
-  repl=${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/hermes-repl
-  hbc-deltaprep=${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/hbc-deltaprep
-  hbc_diff=${HERMES_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/hbc-diff
+  hbc_deltaprep=${HERMES_TOOLS_OUTPUT_DIR}/hbc-deltaprep
+  FileCheck=${HERMES_TOOLS_OUTPUT_DIR}//FileCheck
+  hermes=${HERMES_TOOLS_OUTPUT_DIR}/hermes
+  hermesc=${HERMES_TOOLS_OUTPUT_DIR}/hermesc
+  hdb=${HERMES_TOOLS_OUTPUT_DIR}/hdb
+  hbcdump=${HERMES_TOOLS_OUTPUT_DIR}/hbcdump
+  repl=${HERMES_TOOLS_OUTPUT_DIR}/hermes-repl
+  hbc-deltaprep=${HERMES_TOOLS_OUTPUT_DIR}/hbc-deltaprep
+  hbc_diff=${HERMES_TOOLS_OUTPUT_DIR}/hbc-diff
   build_mode=${HERMES_ASSUMED_BUILD_MODE_IN_LIT_TEST}
   exception_on_oom_enabled=${HERMESVM_EXCEPTION_ON_OOM}
   serialize_enabled=${HERMESVM_SERIALIZE}
@@ -551,11 +534,7 @@ set(HERMES_LIT_TEST_PARAMS
   ubsan=OFF
   )
 
-set(LLVM_LIT_ARGS "-sv")
-
-# This is a hack to help LLVM find its own llvm-lit tool, since we had to set
-# LLVM_RUNTIME_OUTPUT_INTDIR to our own build dir.
-set(LLVM_LIT_OUTPUT_DIR ${LLVM_BUILD_DIR}/${CMAKE_CFG_INTDIR}/bin)
+set(LLVH_LIT_ARGS "-sv")
 
 add_lit_testsuite(check-hermes "Running the Hermes regression tests"
   ${HERMES_SOURCE_DIR}/test