Support LLVM trunk (#3907)

* support LLVM trunk

* guard with USE_LLVM in if condition for c++14

* GREATER_EQUAL -> GREATER

CMakeLists.txt

@@ -90,15 +90,13 @@ if(MSVC)
     endforeach(flag_var)
   endif()
 else(MSVC)
-  include(CheckCXXCompilerFlag)
-  check_cxx_compiler_flag("-std=c++11"    SUPPORT_CXX11)
   if ("${CMAKE_BUILD_TYPE}" STREQUAL "Debug")
     message("Build in Debug mode")
     set(CMAKE_C_FLAGS "-O0 -g -Wall -fPIC ${CMAKE_C_FLAGS} -rdynamic")
-    set(CMAKE_CXX_FLAGS "-O0 -g -Wall -fPIC -std=c++11 ${CMAKE_CXX_FLAGS} -rdynamic")
+    set(CMAKE_CXX_FLAGS "-O0 -g -Wall -fPIC ${CMAKE_CXX_FLAGS} -rdynamic")
   else()
     set(CMAKE_C_FLAGS "-O2 -Wall -fPIC ${CMAKE_C_FLAGS}")
-    set(CMAKE_CXX_FLAGS "-O2 -Wall -fPIC -std=c++11 ${CMAKE_CXX_FLAGS}")
+    set(CMAKE_CXX_FLAGS "-O2 -Wall -fPIC ${CMAKE_CXX_FLAGS}")
     if (HIDE_PRIVATE_SYMBOLS)
       message("Hide private symbols...")
       set(CMAKE_C_FLAGS "-fvisibility=hidden ${CMAKE_C_FLAGS}")
@@ -245,6 +243,19 @@ include(cmake/modules/contrib/Sort.cmake)
 include(cmake/modules/contrib/NNPack.cmake)
 include(cmake/modules/contrib/HybridDump.cmake)
 
+if(NOT MSVC)
+  include(CheckCXXCompilerFlag)
+  if(NOT USE_LLVM STREQUAL "OFF" AND TVM_LLVM_VERSION GREATER 91)
+    check_cxx_compiler_flag("-std=c++14"    SUPPORT_CXX14)
+    message(STATUS "Build with c++14")
+    set(CMAKE_CXX_FLAGS "-std=c++14 ${CMAKE_CXX_FLAGS}")
+  else()
+    check_cxx_compiler_flag("-std=c++11"    SUPPORT_CXX11)
+    message(STATUS "Build with c++11")
+    set(CMAKE_CXX_FLAGS "-std=c++11 ${CMAKE_CXX_FLAGS}")
+  endif()
+endif()
+
 add_library(tvm SHARED ${COMPILER_SRCS} ${RUNTIME_SRCS})
 add_library(tvm_topi SHARED ${TOPI_SRCS})
 add_library(tvm_runtime SHARED ${RUNTIME_SRCS})

src/codegen/llvm/codegen_llvm.cc

@@ -423,8 +423,13 @@ void CodeGenLLVM::GetAlignment(Type t,
 
 std::unique_ptr<CodeGenLLVM::DebugInfo>
 CodeGenLLVM::CreateDebugInfo(llvm::Module* module) {
+#if TVM_LLVM_VERSION >= 100
+  auto debug_info = std::make_unique<CodeGenLLVM::DebugInfo>();
+  debug_info->di_builder_ = std::make_unique<llvm::DIBuilder>(*module);
+#else
   auto debug_info = llvm::make_unique<CodeGenLLVM::DebugInfo>();
   debug_info->di_builder_ = llvm::make_unique<llvm::DIBuilder>(*module);
+#endif
   // TODO(tulloch): pass this information through relay::Span classes to the LoweredFunc instance?
   debug_info->file_ = debug_info->di_builder_->createFile("model.tvm", "/tmp/");
   debug_info->compilation_unit_ = debug_info->di_builder_->createCompileUnit(