Use implicit null checks inside try blocks.

Make implicit null check entrypoint save all registers, use
platform-specific approach to still pass the fault address.
Allow implicit null checks in try blocks.

On Nexus 9, AOSP ToT, the boot.oat size reduction is
  prebuilt multi-part boot image:
    - 32-bit boot.oat: -452KiB (-0.7%)
    - 64-bit boot.oat: -482KiB (-0.7%)
  on-device built single boot image:
    - 32-bit boot.oat: -444KiB (-0.7%)
    - 64-bit boot.oat: -488KiB (-0.7%)

Test: Run ART test suite on host and Nexus 9.
Test: Build aosp_mips64-eng.
Change-Id: I279f3ab57e2e2f338131c5cac45c51b673bdca19
diff --git a/runtime/arch/arm/quick_entrypoints_arm.S b/runtime/arch/arm/quick_entrypoints_arm.S
index a3f053b..3fc83ba 100644
--- a/runtime/arch/arm/quick_entrypoints_arm.S
+++ b/runtime/arch/arm/quick_entrypoints_arm.S
@@ -173,6 +173,29 @@
     /*
      * Macro that sets up the callee save frame to conform with
      * Runtime::CreateCalleeSaveMethod(kSaveEverything)
+     * when core registers are already saved.
+     */
+.macro SETUP_SAVE_EVERYTHING_FRAME_CORE_REGS_SAVED rTemp
+                                        @ 14 words of callee saves and args already saved.
+    vpush {d0-d15}                      @ 32 words, 2 for each of the 16 saved doubles.
+    .cfi_adjust_cfa_offset 128
+    sub sp, #8                          @ 2 words of space, alignment padding and Method*
+    .cfi_adjust_cfa_offset 8
+    RUNTIME_CURRENT1 \rTemp             @ Load Runtime::Current into rTemp.
+    @ Load kSaveEverything Method* into rTemp.
+    ldr \rTemp, [\rTemp, #RUNTIME_SAVE_EVERYTHING_METHOD_OFFSET]
+    str \rTemp, [sp, #0]                @ Place Method* at bottom of stack.
+    str sp, [r9, #THREAD_TOP_QUICK_FRAME_OFFSET]  @ Place sp in Thread::Current()->top_quick_frame.
+
+    // Ugly compile-time check, but we only have the preprocessor.
+#if (FRAME_SIZE_SAVE_EVERYTHING != 56 + 128 + 8)
+#error "FRAME_SIZE_SAVE_EVERYTHING(ARM) size not as expected."
+#endif
+.endm
+
+    /*
+     * Macro that sets up the callee save frame to conform with
+     * Runtime::CreateCalleeSaveMethod(kSaveEverything)
      */
 .macro SETUP_SAVE_EVERYTHING_FRAME rTemp
     push {r0-r12, lr}                   @ 14 words of callee saves and args.
@@ -191,20 +214,7 @@
     .cfi_rel_offset r11, 44
     .cfi_rel_offset ip, 48
     .cfi_rel_offset lr, 52
-    vpush {d0-d15}                      @ 32 words, 2 for each of the 16 saved doubles.
-    .cfi_adjust_cfa_offset 128
-    sub sp, #8                          @ 2 words of space, alignment padding and Method*
-    .cfi_adjust_cfa_offset 8
-    RUNTIME_CURRENT1 \rTemp             @ Load Runtime::Current into rTemp.
-    @ Load kSaveEverything Method* into rTemp.
-    ldr \rTemp, [\rTemp, #RUNTIME_SAVE_EVERYTHING_METHOD_OFFSET]
-    str \rTemp, [sp, #0]                @ Place Method* at bottom of stack.
-    str sp, [r9, #THREAD_TOP_QUICK_FRAME_OFFSET]  @ Place sp in Thread::Current()->top_quick_frame.
-
-    // Ugly compile-time check, but we only have the preprocessor.
-#if (FRAME_SIZE_SAVE_EVERYTHING != 56 + 128 + 8)
-#error "FRAME_SIZE_SAVE_EVERYTHING(ARM) size not as expected."
-#endif
+    SETUP_SAVE_EVERYTHING_FRAME_CORE_REGS_SAVED \rTemp
 .endm
 
 .macro RESTORE_SAVE_EVERYTHING_FRAME
@@ -356,7 +366,34 @@
     /*
      * Call installed by a signal handler to create and deliver a NullPointerException.
      */
-ONE_ARG_RUNTIME_EXCEPTION art_quick_throw_null_pointer_exception_from_signal, artThrowNullPointerExceptionFromSignal
+    .extern art_quick_throw_null_pointer_exception_from_signal
+ENTRY art_quick_throw_null_pointer_exception_from_signal
+    // The fault handler pushes the gc map address, i.e. "return address", to stack
+    // and passes the fault address in LR. So we need to set up the CFI info accordingly.
+    .cfi_def_cfa_offset __SIZEOF_POINTER__
+    .cfi_rel_offset lr, 0
+    push {r0-r12}                   @ 13 words of callee saves and args; LR already saved.
+    .cfi_adjust_cfa_offset 52
+    .cfi_rel_offset r0, 0
+    .cfi_rel_offset r1, 4
+    .cfi_rel_offset r2, 8
+    .cfi_rel_offset r3, 12
+    .cfi_rel_offset r4, 16
+    .cfi_rel_offset r5, 20
+    .cfi_rel_offset r6, 24
+    .cfi_rel_offset r7, 28
+    .cfi_rel_offset r8, 32
+    .cfi_rel_offset r9, 36
+    .cfi_rel_offset r10, 40
+    .cfi_rel_offset r11, 44
+    .cfi_rel_offset ip, 48
+
+    @ save all registers as basis for long jump context
+    SETUP_SAVE_EVERYTHING_FRAME_CORE_REGS_SAVED r1
+    mov r0, lr                      @ pass the fault address stored in LR by the fault handler.
+    mov r1, r9                      @ pass Thread::Current
+    b   artThrowNullPointerExceptionFromSignal  @ (Thread*)
+END art_quick_throw_null_pointer_exception_from_signal
 
     /*
      * Called by managed code to create and deliver an ArithmeticException.