commit 11e96fe48a74e6ab97d4de899684d3a61a9d1129
author Yabin Cui <yabinc@google.com> Wed Mar 14 18:16:22 2018 -0700
committer Christopher Ferris <cferris@google.com> Fri Mar 16 23:38:07 2018 -0700
tree 6a056073b680ed6fe25fb406e5f2b316b991ee3e
parent a411fc65d1fc4c2c1c44d5d0860b31a018b8c9fd

Always set the sp reg to the cfa for DWARF.

There are a few places where it is assumed that this register is
set to the cfa value when interpreting DWARF information.

Add a testcase for unwinding art_quick_osr_stub on ARM.

Bug: 73954823

Test: Ran libunwindstack/libbacktrace unit tests.
Test: Random debuggerd -b of process on a hikey.
Test: Ran the 137 art test on host.
Change-Id: Ida6ccdc38c3cfeea6b57fe861a0cc127b150b790

libunwindstack/ElfInterfaceArm.cpp

diff --git a/libunwindstack/ElfInterfaceArm.cpp b/libunwindstack/ElfInterfaceArm.cpp
index a5afc7e..f93baeb 100644
--- a/libunwindstack/ElfInterfaceArm.cpp
+++ b/libunwindstack/ElfInterfaceArm.cpp
@@ -127,13 +127,9 @@
   if (arm.ExtractEntryData(entry_offset) && arm.Eval()) {
     // If the pc was not set, then use the LR registers for the PC.
     if (!arm.pc_set()) {
-      regs_arm->set_pc((*regs_arm)[ARM_REG_LR]);
-      (*regs_arm)[ARM_REG_PC] = regs_arm->pc();
-    } else {
-      regs_arm->set_pc((*regs_arm)[ARM_REG_PC]);
+      (*regs_arm)[ARM_REG_PC] = (*regs_arm)[ARM_REG_LR];
     }
-    regs_arm->set_sp(arm.cfa());
-    (*regs_arm)[ARM_REG_SP] = regs_arm->sp();
+    (*regs_arm)[ARM_REG_SP] = arm.cfa();
     return_value = true;
 
     // If the pc was set to zero, consider this the final frame.