Fix API 30+ in ndk-build for LP64 ABIs.

Test: Targeted API 30, saw compiler get API 30. Targeted API 16, saw
compiler get API 16 for LP32 and 21 for LP64. Once API 30 sysroot is
submitted I can also add a test that builds against API 30.
Bug: android/ndk#1201
Change-Id: I0183d5e803234b25993944df0de9c8c88e7e2004

build/core/setup-abi.mk

@@ -26,17 +26,19 @@ endif
 
 TARGET_OUT := $(NDK_APP_OUT)/$(_app)/$(TARGET_ARCH_ABI)
 
-# For x86 and mips: the minimal platform level is android-9
-TARGET_PLATFORM_SAVED := $(TARGET_PLATFORM)
+TARGET_PLATFORM_LEVEL := $(APP_PLATFORM_LEVEL)
 
-# For 64-bit ABIs: the minimal platform level is android-21
+# 64-bit ABIs were first supported in API 21. Pull up these ABIs if the app has
+# a lower minSdkVersion.
 ifneq ($(filter $(NDK_KNOWN_DEVICE_ABI64S),$(TARGET_ARCH_ABI)),)
-$(foreach _plat,3 4 5 8 9 10 11 12 13 14 15 16 17 18 19 20,\
-    $(eval TARGET_PLATFORM := $$(subst android-$(_plat),android-21,$$(TARGET_PLATFORM)))\
-)
+    ifneq ($(call lt,$(TARGET_PLATFORM_LEVEL),21),)
+        TARGET_PLATFORM_LEVEL := 21
+    endif
 endif
 
-TARGET_PLATFORM_LEVEL := $(strip $(subst android-,,$(TARGET_PLATFORM)))
+# Not used by ndk-build, but are documented for use by Android.mk files.
+TARGET_PLATFORM := android-$(TARGET_PLATFORM_LEVEL)
+TARGET_ABI := $(TARGET_PLATFORM)-$(TARGET_ARCH_ABI)
 
 # If we're targeting a new enough platform version, we don't actually need to
 # cover any gaps in libc for libc++ support. In those cases, save size in the
@@ -82,6 +84,3 @@ ifeq ($(TARGET_ARCH_ABI),x86_64)
 endif
 
 include $(BUILD_SYSTEM)/setup-toolchain.mk
-
-# Restore TARGET_PLATFORM, see above.
-TARGET_PLATFORM := $(TARGET_PLATFORM_SAVED)

build/core/setup-app.mk

@@ -39,9 +39,6 @@ $(foreach __name,$(NDK_APP_VARS),\
 ndk-app-$(_app): $(NDK_APP_MODULES)
 all: ndk-app-$(_app)
 
-# which platform/abi/toolchain are we going to use?
-TARGET_PLATFORM := $(call get,$(_map),APP_PLATFORM)
-
 # The ABI(s) to use
 NDK_APP_ABI := $(subst $(comma),$(space),$(strip $(NDK_APP_ABI)))
 ifndef NDK_APP_ABI

build/core/setup-toolchain.mk

@@ -17,7 +17,7 @@
 # to setup the target toolchain for a given platform/abi combination.
 #
 
-$(call assert-defined,TARGET_PLATFORM TARGET_ARCH TARGET_ARCH_ABI)
+$(call assert-defined,TARGET_PLATFORM_LEVEL TARGET_ARCH TARGET_ARCH_ABI)
 $(call assert-defined,NDK_APPS NDK_APP_STL)
 
 # Check that we have a toolchain that supports the current ABI.
@@ -61,8 +61,6 @@ else # NDK_TOOLCHAIN is not empty
     TARGET_TOOLCHAIN := $(NDK_TOOLCHAIN)
 endif # NDK_TOOLCHAIN is not empty
 
-TARGET_ABI := $(TARGET_PLATFORM)-$(TARGET_ARCH_ABI)
-
 TARGET_PREBUILT_SHARED_LIBRARIES :=
 
 # Define default values for TOOLCHAIN_NAME, this can be overriden in

docs/changelogs/Changelog-r21.md

@@ -62,8 +62,11 @@ For Android Studio issues, follow the docs on the [Android Studio site].
    debugging. The error from gdb that confirms you were affected by this was
    `gdb-8.3/gdb/psymtab.c:316: internal-error: sect_index_text not initialized`.
  * [Issue 1166]: Rehid unwinder symbols all architectures.
+ * [Issue 1201]: Fixed issue in ndk-build that was causing `APP_PLATFORM` to be
+   corrupted for API 30+ with LP64 ABIs.
 
 [Issue 1166]: https://github.com/android/ndk/issues/1166
+[Issue 1201]: https://github.com/android/ndk/issues/1201
 
 ## Changes