[all-commits] [llvm/llvm-project] 3c36d8: Introduce DWARFDataExtractor::getInitialLength

[Pavel Labath via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 3c36d8dad57712f6616a197632e754541e71edf4
      https://github.com/llvm/llvm-project/commit/3c36d8dad57712f6616a197632e754541e71edf4
  Author: Pavel Labath <pavel at labath.sk>
  Date:   2020-02-26 (Wed, 26 Feb 2020)

  Changed paths:
    M llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h
    M llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp
    M llvm/unittests/DebugInfo/DWARF/CMakeLists.txt
    A llvm/unittests/DebugInfo/DWARF/DWARFDataExtractorTest.cpp

  Log Message:
  -----------
  Introduce DWARFDataExtractor::getInitialLength

Summary:
This patch introduces a function to house the code needed to do the
DWARF64 detection dance. The function decodes the initial length field
and returns it as a pair containing the actual length, and the DWARF
encoding.

This patch does _not_ attempt to handle the problem of detecting lengths
which extend past the size of the section, or cases when reads of a
single contribution accidentally escape beyond its specified length, but
I think it's useful in its own right.

Reviewers: dblaikie, jhenderson, ikudrin

Subscribers: hiraditya, probinson, aprantl, JDevlieghere, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74560