Commit graph

7 commits

Author SHA1 Message Date
Christopher Ferris
c8bec5aa91 Use new unwinder for offline in libbacktrace.
libbbacktrace changes:
- Completely rewrite the BacktraceOffline class to use the new unwinder.
- Modify the test data to save ucontext_t data instead of unw_context data.
- Convert the previous tests from unw_context data to ucontext_t data.

Bug: 65682279

Test: New unit tests pass in libunwindstack.
Test: All offline tests continue to pass.
Change-Id: I540345c304b20199d46deeb0349a0638a0f3ab2f
2018-01-29 10:41:11 -08:00
Yabin Cui
9879137720 libBacktraceOffline: improve unwinding callchains.
1. Extend MAX_BACKTRACE_FRAMES to 256, as we can have callchains
   with length near 256 when recording Android applications.

2. .eh_frame and .ARM.exidx doesn't know how to unwind from instructions
   setting up or destroying stack frames. It can lead to wrong callchains,
   which may contain pcs outside executable mapping areas. Stop unwinding
   once this is detected.

3. Some CIE entries in .eh_frame/.debug_frame suggest unwinder reading
   personality routine from memory. However, that is not available in
   offline unwinding, and leads to ACCESS_MEM_FAILED error. Work around
   this by returning all zero data when failed to read data for some
   addresses.

4. Some libraries have empty .eh_frame_hdr but valid .eh_frame.
   Work around this by building eh_frame_hdr manually.

5. Prefer to use .debug_frame than .eh_frame. Because the former
   can unwind instructions setting up and destroying stack frames.

Bug: http://b/69383534
Test: run backtrace_test.
Test: run simpleperf on some apps.

Change-Id: I62dddda3865dd567c6be150ce5527dc2d3516256
2017-12-18 18:20:44 -08:00
Yabin Cui
0ca49b09ad libBacktraceOffline: try both .debug_frame and .ARM.exidx on arm.
Currently, libBacktraceOffline doesn't try .ARM.exidx if a function
appears in .debug_frame. This make it can't unwind through functions
appear in both .debug_frame and .ARM.exidx, but having dwarf instructions
not accepted by libunwind.
This patch fixes this by trying first .debug_frame then .ARM.exidx on arm.

Bug: http://b/69383534
Test: run libbacktrace_test on arm.

Change-Id: Ib95dd56d5cc123a20948e880b51b28ddc04b4a6e
2017-12-10 18:00:35 -08:00
Yabin Cui
4a26eaf1f1 libBacktraceOffline: fix using debug frame with load bias.
Bug: http://b/69383534
Test: run backtrace_test.
Change-Id: I295d9dc8f3e5b628f179b2eaeac21fa93de130b0
2017-12-06 11:27:06 -08:00
Christopher Ferris
458cc66b07 Update the tests.
- Change all load_base to load_bias in the test files.
- Add the test files to the backtrace_test.
- Add a function to get the path to the test libraries.
- Change aarch64 to arm64 for offline test code.
- Modify the offline tests so that they can be easily updated when
  unwinding on any arch for any other arch is possible.
- Add tests of CreateNew for remote debugging.

Test: Ran unit tests on host and angler.
Change-Id: Id6c5afe73aeb2ac22463dd81f061799fcb1c178b
2017-08-28 18:08:52 -07:00
Yabin Cui
c4a480e423 libbacktraceoffline: choose correct debug section for a given address.
1. In /system/lib/libart.so, the ranges of functions covered by .eh_frame
and .ARM.exidx overlap with each other. Currently, we don't check .eh_frame
if the address is in the ranges of functions covered by .ARM.exidx. It leads
to a wrong unwinding result. So change the logic to first try .eh_frame and
.debug_frame, if it fails, then try .ARM.exidx.
2. Add test for Item 1.

Bug: http://b/35251937
Test: run backtrace_test.

Change-Id: Ic412705617c300bc69b4ece178cc2e1bb3eb765b
2017-02-10 17:51:16 -08:00
Yabin Cui
5d991bc351 libbacktrace_offline: support .ARM.exidx.
1. Read .ARM.exidx and .ARM.extab, provides these data to libunwind
through AccessMem.
2. In FindProcInfo, search .ARM.exidx for the idx entry of function
containing ip.
3. Add structures to store .ARM.exidx info in DebugFrameInfo, and
clean up the structure.
4. Add tests to test each unwind information (.eh_frame, .debug_frame,
.gnu_debugdata, .ARM.exidx) separately.

Bug: http://b/30974693
Test: run backtrace_test.
Test: run simpleperf runtest.py.
Change-Id: I9377a54379158bd35860efcf0e011423be7350d4
2016-12-07 10:25:33 -08:00