Small behavioral changes to the unwinder.
- Be a little more lenient when reading the cies/fdes. If next entry data
winds up incorrect, don't fail, simply stop processing the entries. This
only applies when reading all of the cies/fdes at once.
- Fail to init an eh_frame with no entries and fallback to assuming the
eh_frame has no header instead.
- Change the step to always try debug_frame first which has the most
accurate information.
- Add small unit tests and a couple of offline unit tests to verify
this behavior.
These changes are needed to support offline unwinding since it depends
on this new behavior.
Bug: 65682279
Test: Ran new unit tests.
Change-Id: I3529f1b0c8e14cd7409494e5de2f3c9e78d0855e
diff --git a/libunwindstack/tests/DwarfEhFrameWithHdrTest.cpp b/libunwindstack/tests/DwarfEhFrameWithHdrTest.cpp
index 64b325b..ef2fb32 100644
--- a/libunwindstack/tests/DwarfEhFrameWithHdrTest.cpp
+++ b/libunwindstack/tests/DwarfEhFrameWithHdrTest.cpp
@@ -94,7 +94,13 @@
EXPECT_EQ(0x1000U, this->eh_frame_->TestGetEntriesDataOffset());
EXPECT_EQ(0x100aU, this->eh_frame_->TestGetCurEntriesOffset());
+ // Verify a zero fde count fails to init.
+ this->memory_.SetData32(0x1006, 0);
+ ASSERT_FALSE(this->eh_frame_->Init(0x1000, 0x100));
+ ASSERT_EQ(DWARF_ERROR_NO_FDES, this->eh_frame_->last_error());
+
// Verify an unexpected version will cause a fail.
+ this->memory_.SetData32(0x1006, 126);
this->memory_.SetData8(0x1000, 0);
ASSERT_FALSE(this->eh_frame_->Init(0x1000, 0x100));
ASSERT_EQ(DWARF_ERROR_UNSUPPORTED_VERSION, this->eh_frame_->last_error());