Add a new unwind method on error.
If a function crashes by jumping into unexecutable code, the old method
could not unwind through that. Add a fallback method to set the pc from
the default return address location.
In addition, add a new finished check for steps. This will provide a method
to indicate that this step is the last step. This prevents cases where
the fallback method might be triggered incorrectly.
Update the libbacktrace code to unwind using the new methodology.
Update the unwind tool to use the new unwind methodology.
Add a new option to crasher that calls through a null function.
Create a new object, Unwinder, that encapsulates the a basic unwind. For now,
libbacktrace will still use the custom code.
Added new unit tests to cover the new cases. Also add a test that
crashes calling a nullptr as a function, and then has call frames in
the signal stack.
Bug: 65842173
Test: Pass all unit tests, verify crasher dumps properly.
Change-Id: Ia18430ab107e9f7bdf0e14a9b74710b1280bd7f4
diff --git a/libunwindstack/ElfInterface.cpp b/libunwindstack/ElfInterface.cpp
index be4f88a..46a3f3f 100644
--- a/libunwindstack/ElfInterface.cpp
+++ b/libunwindstack/ElfInterface.cpp
@@ -348,7 +348,7 @@
return false;
}
-bool ElfInterface::Step(uint64_t pc, Regs* regs, Memory* process_memory) {
+bool ElfInterface::Step(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished) {
// Need to subtract off the load_bias to get the correct pc.
if (pc < load_bias_) {
return false;
@@ -357,16 +357,15 @@
// Try the eh_frame first.
DwarfSection* eh_frame = eh_frame_.get();
- if (eh_frame != nullptr && eh_frame->Step(pc, regs, process_memory)) {
+ if (eh_frame != nullptr && eh_frame->Step(pc, regs, process_memory, finished)) {
return true;
}
// Try the debug_frame next.
DwarfSection* debug_frame = debug_frame_.get();
- if (debug_frame != nullptr && debug_frame->Step(pc, regs, process_memory)) {
+ if (debug_frame != nullptr && debug_frame->Step(pc, regs, process_memory, finished)) {
return true;
}
-
return false;
}