Summary:
The bit order of the has_vec and longtbtable bits in the traceback table generated by the XL compiler flipped at some point after v12.1. This is different from the definition is the AIX header debug.h. The change in the XL compiler that caused the deviation from the OS header definition was unintentional. Since both orderings are extant and the XL compiler runtime also expects the ordering defined by the OS, we will correct the output from LLVM to match the defined ordering given by the OS (which is also consistent with the Assembler Language Reference). Mitigation for traceback tables encoded with the wrong ordering is required for either ordering.
Reviewers: XingXue, HubertTong
Differential Revision: https://reviews.llvm.org/D105487
.byte supports string, so if the whole byte list are printable,
we can actually print the string for readability and LIT tests maintainence.
.byte 'H,'e,'l,'l,'o,',,' ,'w,'o,'r,'l,'d
->
.byte "Hello, world"
Reviewed By: hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D102814
Once the default for SimplifyCFG flips, we can no longer pass nullptr
instead of DomTree to SimplifyCFG, so we need to propagate it here.
We don't strictly need to actually preserve DomTree in DwarfEHPrepare,
but we might as well do it, since it's trivial.
SUMMARY:
In order for the runtime on AIX to find the compact unwind section(EHInfo table),
we would need to set the following on the traceback table:
The 6th byte's longtbtable field to true to signal there is an Extended TB Table Flag.
The Extended TB Table Flag to be 0x08 to signal there is an exception handling info presents.
Emit the offset between ehinfo TC entry and TOC base after all other optional portions of traceback table.
The patch is authored by Jason Liu.
Reviewers: David Tenty, Digger Lin
Differential Revision: https://reviews.llvm.org/D92766
Summary:
Not all system assembler supports `.uleb128 label2 - label1` form.
When the target do not support this form, we have to take
alternative manual calculation to get the offsets from them.
Reviewed By: hubert.reinterpretcast
Diffierential Revision: https://reviews.llvm.org/D92058
Summary:
AIX uses the existing EH infrastructure in clang and llvm.
The major differences would be
1. AIX do not have CFI instructions.
2. AIX uses a new personality routine, named __xlcxx_personality_v1.
It doesn't use the GCC personality rountine, because the
interoperability is not there yet on AIX.
3. AIX do not use eh_frame sections. Instead, it would use a eh_info
section (compat unwind section) to store the information about
personality routine and LSDA data address.
Reviewed By: daltenty, hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D91455
zhijian