llvm-project/llvm/tools/llvm-dwarfdump
Pavel Labath f65cfff605 dwarfdump --statistics: Use new location list api
Summary:
This patch removes manual location list handling in the statistics code
and replaces it with the new DWARFDie api, which provides access to a
"cooked" location list. This has the following effects:
- the code now properly handles split-dwarf location lists
- it will automatically support dwarf5 location lists once support for
  those is added
- it properly handles location lists with base address selection entries
- it fixes a bug where the location list code was using the first
  DW_AT_ranges range as a "base address" of the compile unit (it should
  have used DW_AT_low_pc instead. The effect of this was that the
  computation of the start address of a variable in its scope was broken
  for these kinds of compile units. This only manifested itself on
  linked files, since in object files the first DW_AT_ranges range
  normally starts at 0.

Since pretty much every kind of location list was broken in some way,
it's hard to verify that the new implementation is correct -- the output
will be different in all non-trivial cases, and mostly with good reason.

Most of the existing statistics tests continue to pass though, and a
visual inspection of the statistics for non-trivial inputs shows that
the data is more "reasonable" now. I have updated the "dwo statistics"
test to include the new numbers, as the previous ones were completely
bogus, and I have added a targeted test for the "base address" bug.

Reviewers: dblaikie, cmtice, vsk

Subscribers: aprantl, SouraVX, JDevlieghere, djtodoro, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70444
2019-11-21 11:55:21 +01:00
..
fuzzer Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
CMakeLists.txt llvm-dwarfdump: Add an option to collect debug info quality metrics. 2017-10-06 20:24:34 +00:00
LLVMBuild.txt Update the file headers across all of the LLVM projects in the monorepo 2019-01-19 08:50:56 +00:00
Statistics.cpp dwarfdump --statistics: Use new location list api 2019-11-21 11:55:21 +01:00
llvm-dwarfdump.cpp [Tools] Mark output of tools as text if it is text 2019-10-08 08:21:20 +00:00