Use flatbuffer of alternate namespace (pytorch#82952)

Summary: Minimal change to make use of flatbuffer with fbsource namespace.

Test Plan: existing unit tests

Differential Revision: D38494999

Pull Request resolved: pytorch#82952
Approved by: https://github.com/cccclai

buckbuild.bzl

@@ -125,8 +125,8 @@ THIRD_PARTY_LIBS = {
     "XNNPACK": ["//xplat/third-party/XNNPACK:XNNPACK", "//third_party:XNNPACK"],
     "clog": ["//xplat/third-party/clog:clog", "//third_party:clog"],
     "cpuinfo": ["//third-party/cpuinfo:cpuinfo", "//third_party:cpuinfo"],
-    "flatbuffers-api": ["//third-party/flatbuffers:flatbuffers-api", "//third_party:flatbuffers-api"],
-    "flatc": ["//third-party/flatbuffers:flatc", "//third_party:flatc"],
+    "flatbuffers-api": ["//third-party/flatbuffers/fbsource_namespace:flatbuffers-api", "//third_party:flatbuffers-api"],
+    "flatc": ["//third-party/flatbuffers/fbsource_namespace:flatc", "//third_party:flatc"],
     "fmt": ["//third-party/fmt:fmt", "//third_party:fmt"],
     "glog": ["//third-party/glog:glog", "//third_party:glog"],
     "gmock": ["//xplat/third-party/gmock:gtest", "//third_party:gmock"],
@@ -1497,8 +1497,6 @@ def define_buck_targets(
             # "torch/csrc/jit/mobile/compatibility/runtime_compatibility.cpp",
             # "torch/csrc/jit/serialization/unpickler.cpp",
             "torch/csrc/jit/mobile/compatibility/model_compatibility.cpp",
-            "torch/csrc/jit/serialization/pickle.cpp",
-            "torch/csrc/jit/serialization/pickler.cpp",
         ],
         header_namespace = "",
         exported_headers = [
@@ -1714,7 +1712,7 @@ def define_buck_targets(
             "-fexceptions",
             "-frtti",
             "-Wno-deprecated-declarations",
-        ],
+        ] + (["-DFB_XPLAT_BUILD"] if not IS_OSS else []),
         visibility = ["PUBLIC"],
         deps = [
             ":torch_mobile_module",
@@ -1743,7 +1741,7 @@ def define_buck_targets(
             # Need this otherwise USE_KINETO is undefed
             # for mobile
             "-DEDGE_PROFILER_USE_KINETO",
-        ],
+        ] + (["-DFB_XPLAT_BUILD"] if not IS_OSS else []),
         extra_flags = {
             "fbandroid_compiler_flags": ["-frtti"],
         },

test/cpp/jit/test_flatbuffer.cpp

@@ -1800,6 +1800,9 @@ TEST(FlatbufferUpgraderTest, DivScalarInplaceIntV2) {
 namespace torch {
 namespace jit {
 
+#if defined(FBCODE_CAFFE2) or defined(FB_XPLAT_BUILD)
+namespace flatbuffers = flatbuffers_fbsource;
+#endif
 /**
  * An Allocator that can only deallocate (using delete []), counting
  * the number of times that it has been asked to deallocate.

torch/csrc/jit/mobile/flatbuffer_loader.cpp

@@ -50,6 +50,11 @@
 #include <cstdlib>
 #endif
 
+#if defined(FBCODE_CAFFE2) or defined(FB_XPLAT_BUILD)
+namespace flatbuffers = flatbuffers_fbsource;
+#define FLATBUFFERS_MAX_ALIGNMENT FLATBUFFERS_FBSOURCE_MAX_ALIGNMENT
+#endif
+
 namespace torch {
 namespace jit {
 

torch/csrc/jit/serialization/flatbuffer_serializer.cpp

@@ -23,6 +23,11 @@
 #include <torch/csrc/jit/serialization/export.h>
 #include <torch/csrc/jit/serialization/mobile_bytecode_generated.h> // NOLINT
 
+#if defined(FBCODE_CAFFE2) or defined(FB_XPLAT_BUILD)
+namespace flatbuffers = flatbuffers_fbsource;
+#define FLATBUFFERS_MAX_ALIGNMENT FLATBUFFERS_FBSOURCE_MAX_ALIGNMENT
+#endif
+
 namespace torch {
 namespace jit {