Improve READ_BARRIER_MARK_REG for arm32
Use blocked register IP as scratch, avoid pushing in fast path.
Clean up slow path to not have simpler logic and one less memory
write.
Add simple fast path handling for region space TLAB object
allocation.
Test: test-art-target, N6P booting with CC baker
Bug: 30162165
Change-Id: I6594e42d3d6277ffe7bb79df09df8be6bee85eb5
diff --git a/runtime/arch/arm64/quick_entrypoints_arm64.S b/runtime/arch/arm64/quick_entrypoints_arm64.S
index 35f5c56..4289cab 100644
--- a/runtime/arch/arm64/quick_entrypoints_arm64.S
+++ b/runtime/arch/arm64/quick_entrypoints_arm64.S
@@ -2751,7 +2751,7 @@
READ_BARRIER_MARK_REG art_quick_read_barrier_mark_reg13, w13, x13
READ_BARRIER_MARK_REG art_quick_read_barrier_mark_reg14, w14, x14
READ_BARRIER_MARK_REG art_quick_read_barrier_mark_reg15, w15, x15
-READ_BARRIER_MARK_REG art_quick_read_barrier_mark_reg16, w16, x16
+// READ_BARRIER_MARK_REG art_quick_read_barrier_mark_reg16, w16, x16 ip0 is blocked
READ_BARRIER_MARK_REG art_quick_read_barrier_mark_reg17, w17, x17
READ_BARRIER_MARK_REG art_quick_read_barrier_mark_reg18, w18, x18
READ_BARRIER_MARK_REG art_quick_read_barrier_mark_reg19, w19, x19