commit 2502a60ea1a5d612ce5d0c44a121fe314c3ef930
author Christopher Ferris <cferris@google.com> Mon Oct 23 13:51:54 2017 -0700
committer Christopher Ferris <cferris@google.com> Mon Oct 23 14:55:16 2017 -0700
tree b8f0f043f8762467120b4c1a70d8a4c0ec5c0811
parent 26b614ddf6a135e37ffd5c2b2a619fdf90569de4

If the pc is set to zero, the unwind is done.

Bug: 68047085

Test: Ran new unit tests, verified new unwinder does not show an
Test: extra pc zero frame for arm 32 bit processes.
Change-Id: Ic6532e56fbb786a8b7d41638abae777c2d0f1d59

libunwindstack/tests/ElfInterfaceArmTest.cpp

diff --git a/libunwindstack/tests/ElfInterfaceArmTest.cpp b/libunwindstack/tests/ElfInterfaceArmTest.cpp
index feb24ce..4b621c9 100644
--- a/libunwindstack/tests/ElfInterfaceArmTest.cpp
+++ b/libunwindstack/tests/ElfInterfaceArmTest.cpp
@@ -401,4 +401,40 @@
   ASSERT_EQ(0x1234U, regs.pc());
 }
 
+TEST_F(ElfInterfaceArmTest, StepExidx_pc_zero) {
+  ElfInterfaceArmFake interface(&memory_);
+
+  interface.FakeSetStartOffset(0x1000);
+  interface.FakeSetTotalEntries(1);
+  memory_.SetData32(0x1000, 0x6000);
+  // Set the pc using a pop r15 command.
+  memory_.SetData32(0x1004, 0x808800b0);
+
+  // pc value of zero.
+  process_memory_.SetData32(0x10000, 0);
+
+  RegsArm regs;
+  regs[ARM_REG_SP] = 0x10000;
+  regs[ARM_REG_LR] = 0x20000;
+  regs.set_sp(regs[ARM_REG_SP]);
+  regs.set_pc(0x1234);
+
+  bool finished;
+  ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
+  ASSERT_TRUE(finished);
+  ASSERT_EQ(0U, regs.pc());
+
+  // Now set the pc from the lr register (pop r14).
+  memory_.SetData32(0x1004, 0x808400b0);
+
+  regs[ARM_REG_SP] = 0x10000;
+  regs[ARM_REG_LR] = 0x20000;
+  regs.set_sp(regs[ARM_REG_SP]);
+  regs.set_pc(0x1234);
+
+  ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
+  ASSERT_TRUE(finished);
+  ASSERT_EQ(0U, regs.pc());
+}
+
 }  // namespace unwindstack