Splice the softfp shims before the sysroot leaves for stage 2

CMakeLists.txt

@@ -303,6 +303,27 @@ if(NOT VITASDK_TARGET_ONLY)
 endif()
 include(cmake/recipes/BuildGccFinal.cmake)
 include(cmake/recipes/Provenance.cmake)
+
+# What the target half is made of, named once because two things wait for it:
+# the export that hands stage 2 a sysroot, and the finalize barrier of a build
+# that keeps its own. One of them forgetting a piece is invisible until
+# something reads the result -- the softfp shims were spliced by finalize-sdk
+# and not by the export, so a staged build shipped stage 2 a sysroot whose
+# stub archives had never been patched, and the ABI contract test found it
+# there rather than here.
+set(target_half_dependencies
+    ${gcc_final_barrier}
+    vita-headers
+    newlib
+    pthread-embedded
+    samples
+    ${version_info_file})
+if(VITASDK_FLOAT_ABI STREQUAL "softfp" AND NOT VITASDK_STAGE1_DIR)
+    # Stage 2 imports the archives already spliced; there is nothing to splice
+    # and no softfp-shim target, since the components are not built there.
+    list(APPEND target_half_dependencies softfp-shim)
+endif()
+
 if(VITASDK_TARGET_ONLY)
     include(cmake/recipes/ExportSysroot.cmake)
 else()

cmake/recipes/ExportSysroot.cmake

@@ -43,8 +43,7 @@ add_custom_target(sysroot
         -P ${CMAKE_SOURCE_DIR}/cmake/CopySysroot.cmake
     COMMAND ${CMAKE_COMMAND} -E tar "cfj" ${CMAKE_BINARY_DIR}/${sysroot_tarball} vitasdk
     WORKING_DIRECTORY ${sysroot_root}
-    DEPENDS ${gcc_final_barrier} vita-headers newlib pthread-embedded samples
-        ${version_info_file}
+    DEPENDS ${target_half_dependencies}
     COMMENT "Exporting the target half to ${sysroot_tarball}"
     VERBATIM
     )

cmake/recipes/FinalizeSdk.cmake

@@ -33,22 +33,12 @@ set(finalize_sdk_dependencies
     vita-toolchain_${target_suffix}
     binutils_${target_suffix}
     gdb_${target_suffix}
-    vita-headers
-    newlib
-    pthread-embedded
-    samples
     vdpm
     vita-makepkg
-    ${gcc_final_barrier}
-    ${version_info_file})
+    ${target_half_dependencies})
 if(BUILD_PACMAN_CLIENT)
     list(APPEND finalize_sdk_dependencies package-client-configuration)
 endif()
-if(VITASDK_FLOAT_ABI STREQUAL "softfp")
-    # Splice the softfp shims into the stub archives before finalize-sdk
-    # strips them (cmake/strip_target_objects.cmake), not after.
-    list(APPEND finalize_sdk_dependencies softfp-shim)
-endif()
 
 # Target objects are stripped where they are produced. In stage 2 they arrive
 # already stripped from stage 1, and the objcopy that would do it belongs to

tests/cmake/target-half-dependencies.cmake

@@ -0,0 +1,56 @@
+# The export and the finalize barrier wait for the same target half.
+#
+# They are mutually exclusive -- a producer exports a sysroot for stage 2, any
+# other build finalizes its own -- so a piece added to one and forgotten in the
+# other is invisible until something reads the result. The softfp shims were
+# spliced by finalize-sdk and not by the export, so a staged build handed
+# stage 2 a sysroot whose stub archives had never been patched, and the ABI
+# contract test found it two jobs later.
+
+cmake_minimum_required(VERSION 3.16)
+
+get_filename_component(repository_root "${CMAKE_CURRENT_LIST_DIR}/../.." ABSOLUTE)
+set(failures 0)
+
+function(expect_contains path needle description)
+    file(READ "${repository_root}/${path}" contents)
+    string(FIND "${contents}" "${needle}" position)
+    if(position EQUAL -1)
+        message(SEND_ERROR "FAIL: ${description}")
+        math(EXPR failures "${failures} + 1")
+        set(failures ${failures} PARENT_SCOPE)
+    endif()
+endfunction()
+
+function(expect_absent path needle description)
+    file(READ "${repository_root}/${path}" contents)
+    string(FIND "${contents}" "${needle}" position)
+    if(NOT position EQUAL -1)
+        message(SEND_ERROR "FAIL: ${description}")
+    endif()
+endfunction()
+
+# Both consumers take the list; neither spells the target half out again.
+expect_contains("cmake/recipes/ExportSysroot.cmake"
+    "DEPENDS \${target_half_dependencies}"
+    "the sysroot export does not wait for the target half")
+expect_contains("cmake/recipes/FinalizeSdk.cmake"
+    "\${target_half_dependencies})"
+    "finalize-sdk does not wait for the target half")
+
+# The splice belongs to the list and nowhere else, or the two drift again.
+expect_absent("cmake/recipes/ExportSysroot.cmake" "softfp-shim"
+    "ExportSysroot.cmake names softfp-shim itself instead of taking the list")
+expect_absent("cmake/recipes/FinalizeSdk.cmake" "softfp-shim"
+    "FinalizeSdk.cmake names softfp-shim itself instead of taking the list")
+
+# A softfp world whose shims were never spliced is a toolchain that
+# miscompiles quietly, so the list carries them exactly when the world is one.
+expect_contains("CMakeLists.txt"
+    "list(APPEND target_half_dependencies softfp-shim)"
+    "the softfp splice is not part of the target half")
+expect_contains("CMakeLists.txt"
+    "VITASDK_FLOAT_ABI STREQUAL \"softfp\""
+    "nothing decides when the splice belongs to the target half")
+
+message(STATUS "target half dependency tests passed")