[Build] (CMakeLists.txt, docs/Disaggregated): default to the split in-process build

[Feat] (Disaggregated): replace MobileGL's monolithic architecture with a disaggregated client/server one

CMakeLists.txt

@@ -14,20 +14,20 @@ option(MOBILEGL_ENABLE_TRACY      "Enable tracy for profiling"
 option(MOBILEGL_BUILD_TRACE_REPLAY "Build desktop apitrace replay runner"            OFF)
 option(MOBILEGL_TRACE_ANGLE_VARIANTS "Enable signed trace-APK ANGLE variant loading" OFF)
 option(MOBILEGL_IOS               "Build MobileGL for iOS instead of macOS when APPLE is set" OFF)
-# The disaggregated (two-process) shape. OFF is the shipping default and OFF
-# must stay byte-comparable to a tree without MG_Remote at all: nothing under
-# MobileGL/MG_Remote/ is compiled, no include path is added, and no library is
-# linked, so `nm --defined-only libMobileGL.so | grep -i MG_Remote` is empty.
-# That emptiness is one of the two byte-level equalities the plan's validation
-# gates keep (section 10.3).
-option(MOBILEGL_BUILD_DISAGGREGATED "Build the MG_Remote transport layer (two-process shape)" OFF)
-# The CI / debugging shape (ARCHITECTURE.md §16): both roles in ONE process, talking over the
-# same SEG_CMD ring and the same G3 codec a spawned server would use. It IMPLIES
-# MOBILEGL_BUILD_DISAGGREGATED (below) and additionally admits the role-isolation shims that
-# only make sense when the two roles share an address space. It is a SUPERSET, never a
-# substitute: MOBILEGL_TRANSPORT=inproc is what selects the shape at run time, and this option
-# only decides whether the shims are compiled in.
-option(MOBILEGL_BUILD_DISAGGREGATED_INPROC "Compile the in-process (one-process, two-role) split shims; implies MOBILEGL_BUILD_DISAGGREGATED" OFF)
+# The disaggregated (two-process) shape, ON by default: the split is the development default and
+# the shipping library configures with -DMOBILEGL_BUILD_DISAGGREGATED=OFF. That OFF build must
+# stay byte-comparable to a tree without MG_Remote at all: nothing under MobileGL/MG_Remote/ is
+# compiled, no include path is added, and no library is linked, so
+# `nm --defined-only libMobileGL.so | grep -i MG_Remote` is empty. That emptiness is one of the
+# two byte-level equalities the plan's validation gates keep (section 10.3).
+option(MOBILEGL_BUILD_DISAGGREGATED "Build the MG_Remote transport layer (two-process shape)" ON)
+# The in-process split shape (ARCHITECTURE.md §16), ON by default with the option above: both
+# roles in ONE process, talking over the same SEG_CMD ring and the same G3 codec a spawned server
+# would use. It IMPLIES MOBILEGL_BUILD_DISAGGREGATED (below) and additionally admits the
+# role-isolation shims that only make sense when the two roles share an address space. It is a
+# SUPERSET, never a substitute: MOBILEGL_TRANSPORT=inproc is what selects the shape at run time,
+# and this option only decides whether the shims are compiled in.
+option(MOBILEGL_BUILD_DISAGGREGATED_INPROC "Compile the in-process (one-process, two-role) split shims; implies MOBILEGL_BUILD_DISAGGREGATED" ON)
 option(MOBILEGL_BUILD_SERVER_SPIKE "Build the P0 spike-A MobileGLServer delivery-chain executable (Android only)" OFF)
 option(MOBILEGL_BUILD_EXTMEM_PROBE "Package tools/spikes/extmem_probe as libMobileGLExtmemProbe.so for the trace APK's exec hook (P11 A3, Android only)" OFF)
 option(MOBILEGL_EXTMEM_PROBE_AS_SERVER "Spike only (P11 B2 step 1): also package the probe as libMobileGLServer.so, the real server as libMobileGLServerReal.so" OFF)

docs/Disaggregated/design/09-build-switches-counters.md

@@ -18,9 +18,9 @@ MobileGL/MG_Remote/          only with MOBILEGL_BUILD_DISAGGREGATED: CONTRACT-*.
               SurfaceControlFrame, ServerDisplay, InProcessServer, DisplayServerJni
 ```
 
-- `MOBILEGL_BUILD_DISAGGREGATED` (default OFF) adds `MG_Remote/**`; when OFF, `MG_Config::Transport` is a `constexpr Monolith`. `MOBILEGL_BUILD_DISAGGREGATED_INPROC` implies the former and adds role isolation: the two roles are separated by the apply thread and the control mailbox, rather than by adding TLS to the 1494 `pGLContext->` read points.
+- `MOBILEGL_BUILD_DISAGGREGATED` (default ON) adds `MG_Remote/**`; when OFF, `MG_Config::Transport` is a `constexpr Monolith`. `MOBILEGL_BUILD_DISAGGREGATED_INPROC` implies the former and adds role isolation: the two roles are separated by the apply thread and the control mailbox, rather than by adding TLS to the 1494 `pGLContext->` read points.
 - `MOBILEGL_TRANSPORT = monolith | inproc | spawn` is the **topology** (G1-relevant); the control plane and data plane are selected by the two variables in §11.9. **A split build with `MOBILEGL_TRANSPORT` unset is the monolith control arm**.
-- Three build flavors (since P13): default (the monolith record arm, with `MG_Remote` not compiled, the shipping shape), verify, and split; Android has two APK flavors (monolith / split). The pull build and the `MOBILEGL_PIPE_PUSH` CMake option are deleted in P13.
+- Three build flavors (since P13): default (the split shape, `MG_Remote` compiled, the in-process shims), verify, and monolith (the shipping shape: configure with `-DMOBILEGL_BUILD_DISAGGREGATED=OFF`, `MG_Remote` not compiled); Android has two APK flavors (monolith / split). The pull build and the `MOBILEGL_PIPE_PUSH` CMake option are deleted in P13.
 - Modules (P13 W7): `SOURCE_FILES` is split into seven OBJECT libraries according to the link ratchet's PARTITION, and `MobileGL` / `MobileGL_s` are assembled from them; in a split build `MobileGL_server_linkcheck` links only the SERVER and SHARED modules with `--no-undefined`, so a frontend reference outside the baseline fails at build time (`scripts/ci/server_link_check.py`). The record arm's server-side code is in `MG_Backend/Record/` (`RecordVerbSink`, `StagedShadow`, `StagedTextureStore`), and client verb emission is in `MG_Impl/Pipe/Verb/`, no longer depending on `MG_Remote`.
 - Test wiring: the ctest `ENVIRONMENT` is built with `mgl_itest_join_environment(...)`; every split / spawn / tcp entry has its own log path, and logs are split per role (`<base>.client.log` / `<base>.server.log`); the spawn and tcp lanes match the split name set (`scripts/ci/spawn_lane_parity.py`), and each entry records its arm proof.
 - CI (`.github/workflows/test.yml`, `apk.yml`): `pipe-gates` (G1–G8, the generator self-test, the symbol report, dirty-surface, field ownership, G5, the documentation-reference lint), `flatc-check`, the include closure, the build / integration / retrace lanes of each flavor, APK + AVD. The `feat/disaggregated` triggers in both workflows are temporary and are removed before merging into `dev`.
@@ -40,7 +40,7 @@ Every lane in `MG_IntegrationTest/CMakeLists.txt` must be able to go red for the
 
 ## Appendix A: switches
 
-CMake: `MOBILEGL_BUILD_DISAGGREGATED` (OFF), `MOBILEGL_BUILD_DISAGGREGATED_INPROC` (OFF, implies the former), `MOBILEGL_PIPE_VERIFY` (OFF, never ships), `MOBILEGL_BUILD_SERVER_SPIKE` (Android spike only), `MOBILEGL_FLATC_EXECUTABLE` (serves `flatc-check` only). `MOBILEGL_PIPE_PUSH` and `MOBILEGL_PIPE_LEGACY_MEMOS` are deleted in P13 (an OFF in an old cache only warns and is ignored).
+CMake: `MOBILEGL_BUILD_DISAGGREGATED` (ON), `MOBILEGL_BUILD_DISAGGREGATED_INPROC` (ON, implies the former), `MOBILEGL_PIPE_VERIFY` (OFF, never ships), `MOBILEGL_BUILD_SERVER_SPIKE` (Android spike only), `MOBILEGL_FLATC_EXECUTABLE` (serves `flatc-check` only). `MOBILEGL_PIPE_PUSH` and `MOBILEGL_PIPE_LEGACY_MEMOS` are deleted in P13 (an OFF in an old cache only warns and is ignored).
 
 At runtime, MGPipe (`MobileGL/Config.h`, `ConfigLoader.cpp`):