[PATCH] D65178: WIP: [DWARF] Collect statistics for DW_OP_entry_value

[Eric Christopher via llvm-commits]

I guess? I'm curious what we'd get out of it in general? Is the
thought that we could try to classify how often we have to do more
work to recover parameters? Not against it, just trying to see why :)


On Tue, Jul 23, 2019 at 5:27 PM Vedant Kumar via Phabricator
<reviews at reviews.llvm.org> wrote:
>
> vsk created this revision.
> Herald added subscribers: hiraditya, aprantl.
> Herald added a project: LLVM.
>
> It might be interesting to see how many parameters with entry_value locations there are compared to how many parameters-with-location there are overall.
>
> I can clean up this patch and push it forward if there's general interest. Here are some numbers from a stage2 RelAsserts build of clang.
>
>   ~/src/builds/llvm-project-master-stage2-RA (0) $ ../llvm-project-master-RA/bin/llvm-dwarfdump --statistics ./bin/clang.dSYM | ppjson
>   { 'call site entries': 6113835,
>     'file':  'bin/clang.dSYM/Contents/Resources/DWARF/clang',
>     'formal params with binary location': 5928235,
>     'formal params with binary location containing entry value': 0,
>     'formal params with source location': 4200769,
>     'formal params with type': 8436986,
>     'format':  'Mach-O 64-bit x86-64',
>     'inlined funcs with abstract origins': 5859344,
>     'inlined functions': 5859344,
>     'scope bytes covered': 563026378,
>     'scope bytes total': 969630990,
>     'source functions': 468524,
>     'source functions with location': 468075,
>     'source variables': 10246465,
>     'total formal params': 8436986,
>     'total function size': 65502932,
>     'total inlined function size': 48065586,
>     'total vars': 1142370,
>     'unique source variables': 1408162,
>     'variables with location': 6751342,
>     'vars with binary location': 710703,
>     'vars with source location': 1059166,
>     'vars with type': 1142370,
>     'version': 3}
>
>   (with -femit-debug-entry-values)
>   ~/src/builds/param-entry-vals-stage2 (0) $ ../llvm-project-master-RA/bin/llvm-dwarfdump --statistics ./bin/clang.dSYM | ppjson
>   { 'call site entries': 6471968,
>     'file':  'bin/clang.dSYM/Contents/Resources/DWARF/clang',
>     'formal params with binary location': 5928218,
>     'formal params with binary location containing entry value': 70017,
>     'formal params with source location': 4200754,
>     'formal params with type': 8437413,
>     'format':  'Mach-O 64-bit x86-64',
>     'inlined funcs with abstract origins': 5859331,
>     'inlined functions': 5859331,
>     'scope bytes covered': 580573865,
>     'scope bytes total': 969629704,
>     'source functions': 468520,
>     'source functions with location': 468071,
>     'source variables': 10246437,
>     'total formal params': 8437413,
>     'total function size': 65502621,
>     'total inlined function size': 48065442,
>     'total vars': 1142364,
>     'unique source variables': 1408152,
>     'variables with location': 6751217,
>     'vars with binary location': 710704,
>     'vars with source location': 1059160,
>     'vars with type': 1142364,
>     'version': 3}
>
>
> https://reviews.llvm.org/D65178
>
> Files:
>   llvm/include/llvm/DebugInfo/DWARF/DWARFExpression.h
>   llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp
>   llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
>   llvm/tools/llvm-dwarfdump/Statistics.cpp
>