From 08e70dd51effb43f143b96e49e89f3754cded340 Mon Sep 17 00:00:00 2001
From: Dave Bort <dbort@meta.com>
Date: Mon, 18 Mar 2024 11:05:26 -0700
Subject: [PATCH 1/2] Fix flatcc + pybindings linking on linux (#2467)

Summary:

On some linux systems, the pybindings build would fail with

`relocation R_X86_64_32 against '.rodata' can not be used when making a shared object; recompile with -fPIC`

Digging into it further, I also noticed that etdump was depending on `libflatcc` (the compiler) instead of `libflatccrt` (the runtime).

Fix that dep, then mark `flatccrt` as positition-independent (thus adding `-fPIC` on appropriate systems) to fix the pybindings build.

Reviewed By: larryliu0820

Differential Revision: D54966723
---
 CMakeLists.txt     | 1 -
 sdk/CMakeLists.txt | 9 +++++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 778b7886ccf..163c1bc0a8a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -453,7 +453,6 @@ if(EXECUTORCH_BUILD_PYBIND)
       etdump
       executorch
       extension_data_loader
-      flatcc
       portable_ops_lib
       util
       torch
diff --git a/sdk/CMakeLists.txt b/sdk/CMakeLists.txt
index 05df3ba6ded..58a0dc52977 100644
--- a/sdk/CMakeLists.txt
+++ b/sdk/CMakeLists.txt
@@ -53,6 +53,11 @@ endforeach()
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/../third-party/flatcc
                  ${CMAKE_BINARY_DIR}/third-party/flatcc)
 
+# Fix for "relocation R_X86_64_32 against `.rodata' can not be used when making
+# a shared object; recompile with -fPIC" when building on some x86 linux
+# systems.
+set_property(TARGET flatccrt PROPERTY POSITION_INDEPENDENT_CODE ON)
+
 # Assume we are cross-compiling and the CMAKE_TOOLCHAIN_FILE is set
 include(ExternalProject)
 
@@ -118,7 +123,7 @@ add_library(etdump ${CMAKE_CURRENT_SOURCE_DIR}/etdump/etdump_flatcc.cpp
 
 target_link_libraries(
   etdump
-  PUBLIC etdump_schema flatcc
+  PUBLIC etdump_schema flatccrt
   PRIVATE executorch)
 
 add_custom_command(
@@ -148,7 +153,7 @@ target_include_directories(
 
 # Install libraries
 install(
-  TARGETS bundled_program etdump flatcc
+  TARGETS bundled_program etdump flatccrt
   DESTINATION ${CMAKE_BINARY_DIR}/lib
   INCLUDES
   DESTINATION ${_common_include_directories})

From 98736c6711fcb7d39571f9b806a3ae36b42eca97 Mon Sep 17 00:00:00 2001
From: Dave Bort <dbort@meta.com>
Date: Mon, 18 Mar 2024 11:05:26 -0700
Subject: [PATCH 2/2] Don't build unnecessary flatbuffers/flatcc targets
 (#2466)

Summary:

We're currently building unnecessary pieces of the flatbuffers and flatcc submodules. I had tried disabling them before for flatbuffers, but didn't do it the right way.

Now do it the right way, saving us some time during the build.

Differential Revision: D54966722
---
 CMakeLists.txt     | 10 +++++-----
 sdk/CMakeLists.txt |  3 +++
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 163c1bc0a8a..43aadfcc9d3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -236,11 +236,11 @@ if(EXECUTORCH_BUILD_FLATC)
     )
   endif()
   set(FLATC_EXECUTABLE flatc)
-  option(FLATBUFFERS_BUILD_FLATC "" ON)
-  option(FLATBUFFERS_BUILD_FLATHASH "" OFF)
-  option(FLATBUFFERS_BUILD_FLATLIB "" OFF)
-  option(FLATBUFFERS_BUILD_TESTS "" OFF)
-  option(FLATBUFFERS_INSTALL "" OFF)
+  set(FLATBUFFERS_BUILD_FLATC ON CACHE BOOL "")
+  set(FLATBUFFERS_BUILD_FLATHASH OFF CACHE BOOL "")
+  set(FLATBUFFERS_BUILD_FLATLIB OFF CACHE BOOL "")
+  set(FLATBUFFERS_BUILD_TESTS OFF CACHE BOOL "")
+  set(FLATBUFFERS_INSTALL OFF CACHE BOOL "")
   add_subdirectory(third-party/flatbuffers)
 endif()
 if(NOT FLATC_EXECUTABLE)
diff --git a/sdk/CMakeLists.txt b/sdk/CMakeLists.txt
index 58a0dc52977..af43434ca29 100644
--- a/sdk/CMakeLists.txt
+++ b/sdk/CMakeLists.txt
@@ -50,6 +50,8 @@ foreach(schema_file ${_bundled_input_schema_names})
        "${CMAKE_CURRENT_SOURCE_DIR}/bundled_program/schema/${schema_file}")
 endforeach()
 
+set(FLATCC_TEST OFF CACHE BOOL "")
+set(FLATCC_REFLECTION OFF CACHE BOOL "")
 add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/../third-party/flatcc
                  ${CMAKE_BINARY_DIR}/third-party/flatcc)
 
@@ -72,6 +74,7 @@ ExternalProject_Add(
   PREFIX ${CMAKE_BINARY_DIR}/_host_build
   SOURCE_DIR ${CMAKE_SOURCE_DIR}/third-party/flatcc
   BINARY_DIR ${CMAKE_BINARY_DIR}/_host_build
+  CMAKE_CACHE_ARGS -DFLATCC_TEST:BOOL=OFF -DFLATCC_REFLECTION:BOOL=OFF
   INSTALL_COMMAND "" # Prevent the install step, modify as needed
 )