This patch adds an implementation of unwinding using PE EH info. It allows to
get almost ideal call stacks on 64-bit Windows systems (except some epilogue
cases, but I believe that they can be fixed with unwind plan disassembly
augmentation in the future).
To achieve the goal the CallFrameInfo abstraction was made. It is based on the
DWARFCallFrameInfo class interface with a few changes to make it less
DWARF-specific.
To implement the new interface for PECOFF object files the class PECallFrameInfo
was written. It uses the next helper classes:
- UnwindCodesIterator helps to iterate through UnwindCode structures (and
processes chained infos transparently);
- EHProgramBuilder with the use of UnwindCodesIterator constructs EHProgram;
- EHProgram is, by fact, a vector of EHInstructions. It creates an abstraction
over the low-level unwind codes and simplifies work with them. It contains
only the information that is relevant to unwinding in the unified form. Also
the required unwind codes are read from the object file only once with it;
- EHProgramRange allows to take a range of EHProgram and to build an unwind row
for it.
So, PECallFrameInfo builds the EHProgram with EHProgramBuilder, takes the ranges
corresponding to every offset in prologue and builds the rows of the resulted
unwind plan. The resulted plan covers the whole range of the function except the
epilogue.
Reviewers: jasonmolenda, asmith, amccarth, clayborg, JDevlieghere, stella.stamenova, labath, espindola
Reviewed By: jasonmolenda
Subscribers: leonid.mashinskiy, emaste, mgorny, aprantl, arichardson, MaskRay, lldb-commits, llvm-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D67347
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374528
91177308-0d34-0410-b5e6-
96231b3b80d8
projects / llvm / commitdiff