[libcxxabi] r217459 - Implement post-review comments for r216730
Jonathan Roelofs
jonathan at codesourcery.com
Tue Sep 9 13:20:52 PDT 2014
Author: jroelofs
Date: Tue Sep 9 15:20:52 2014
New Revision: 217459
URL: http://llvm.org/viewvc/llvm-project?rev=217459&view=rev
Log:
Implement post-review comments for r216730
Feedback was 'this could use better comments'.
Modified:
libcxxabi/trunk/src/Unwind/Unwind-EHABI.cpp
Modified: libcxxabi/trunk/src/Unwind/Unwind-EHABI.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/Unwind/Unwind-EHABI.cpp?rev=217459&r1=217458&r2=217459&view=diff
==============================================================================
--- libcxxabi/trunk/src/Unwind/Unwind-EHABI.cpp (original)
+++ libcxxabi/trunk/src/Unwind/Unwind-EHABI.cpp Tue Sep 9 15:20:52 2014
@@ -218,11 +218,25 @@ extern "C" const uint32_t*
decode_eht_entry(const uint32_t* data, size_t* off, size_t* len) {
if ((*data & 0x80000000) == 0) {
// 6.2: Generic Model
- *off = 1; // First byte is size data.
- *len = (((data[1] >> 24) & 0xff) + 1) * 4;
+ // EHT entry is a prel31 pointing to the PR, followed by data understood only
+ // by the personality routine. Since EHABI doesn't guarantee the location or
+ // availability of the unwind opcodes in the generic model, we have to check
+ // for them on a case-by-case basis:
+ _Unwind_Reason_Code __gxx_personality_v0(int version, _Unwind_Action actions,
+ uint64_t exceptionClass,
+ _Unwind_Exception* unwind_exception,
+ _Unwind_Context* context);
+ void *PR = (void*)signExtendPrel31(*data);
+ if (PR == &__gxx_personality_v0) {
+ *off = 1; // First byte is size data.
+ *len = (((data[1] >> 24) & 0xff) + 1) * 4;
+ } else
+ return nullptr;
data++; // Skip the first word, which is the prel31 offset.
} else {
// 6.3: ARM Compact Model
+ // EHT entries here correspond to the __aeabi_unwind_cpp_pr[012] PRs indeded
+ // by format:
Descriptor::Format format =
static_cast<Descriptor::Format>((*data & 0x0f000000) >> 24);
switch (format) {
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