Commit graph

60 commits

Author SHA1 Message Date
Andrew Kelley
1792258dc8 std.debug.Dwarf: precompute .debug_line table
yields a 60x speedup for resolveSourceLocations in debug builds
2024-08-07 00:48:32 -07:00
Andrew Kelley
66954e8330 std.debug.FixedBufferReader is fine
it does not need to be deprecated
2024-08-07 00:48:32 -07:00
Andrew Kelley
de47acd732 code coverage dumping tool basic implementation
* std.debug.Dwarf: add `sortCompileUnits` along with a field to track
  the state for the purpose of assertions and correct API usage.
  This makes batch lookups faster.
  - in the future, findCompileUnit should be enhanced to rely on sorted
    compile units as well.
* implement `std.debug.Dwarf.resolveSourceLocations` as well as
  `std.debug.Info.resolveSourceLocations`. It's still pretty slow, since
  it calls getLineNumberInfo for each array element, repeating a lot of
  work unnecessarily.
* integrate these APIs with `std.Progress` to understand what is taking
  so long.

The output I'm seeing from this tool shows a lot of missing source
locations. In particular, the main area of interest is missing for my
tokenizer fuzzing example.
2024-08-07 00:48:32 -07:00
Andrew Kelley
2e12b45d8b introduce tool for dumping coverage file
with debug info resolved.

begin efforts of providing `std.debug.Info`, a cross-platform
abstraction for loading debug information into an in-memory format that
supports queries such as "what is the source location of this virtual
memory address?"

Unlike `std.debug.SelfInfo`, this API does not assume the debug
information in question happens to match the host CPU architecture, OS,
or other target properties.
2024-08-07 00:48:32 -07:00
Andrew Kelley
6d606cc38b reintroduce std.Dwarf.abi.supportsUnwinding
There are two concepts here: one for whether dwarf supports unwinding on
that target, and another for whether the Zig standard library
implements it yet.
2024-08-02 14:15:03 -07:00
Andrew Kelley
975c185b92 fix compilation on powerpc GNU systems
...which have a ucontext_t but not a PC register. The current stack
unwinding implementation does not yet support this architecture.

Also fix name of `std.debug.SelfInfo.openSelf` to remove redundancy.

Also removed this hook into root providing an "openSelfDebugInfo"
function. Sorry, this debugging code is not of sufficient quality to
offer a plugin API right now.
2024-08-02 14:14:59 -07:00
Andrew Kelley
48d584e3a3 std.debug: reorg and clarify API goals
After this commit:

`std.debug.SelfInfo` is a cross-platform abstraction for the current
executable's own debug information, with a goal of minimal code bloat
and compilation speed penalty.

`std.debug.Dwarf` does not assume the current executable is itself the
thing being debugged, however, it does assume the debug info has the
same CPU architecture and OS as the current executable. It is planned to
remove this limitation.
2024-08-01 23:11:59 -07:00
Andrew Kelley
290966c249 std.debug: rename Info to SelfInfo
This code has the hard-coded goal of supporting the executable's own
debug information and makes design choices along that goal, such as
memory-mapping the inputs, using dl_iterate_phdr, and doing conditional
compilation on the host target.

A more general-purpose implementation of debug information may be able
to share code with this, but there are some fundamental
incompatibilities. For example, the "SelfInfo" implementation wants to
avoid bloating the binary with PDB on POSIX systems, and likewise DWARF
on Windows systems, while a general-purpose implementation needs to
support both PDB and DWARF from the same binary. It might, for example,
inspect the debug information from a cross-compiled binary.

`SourceLocation` now lives at `std.debug.SourceLocation` and is
documented.

Deprecate `std.debug.runtime_safety` because it returns the optimization
mode of the standard library, when the caller probably wants to use the
optimization mode of their own module.

`std.pdb.Pdb` is moved to `std.debug.Pdb`, mirroring the recent
extraction of `std.debug.Dwarf` from `std.dwarf`.

I have no idea why we have both Module (with a Windows-specific
definition) and WindowsModule. I left some passive aggressive doc
comments to express my frustration.
2024-08-01 22:11:35 -07:00
Andrew Kelley
1ba6b56c81 std.debug.Info: extract to separate file 2024-08-01 22:11:23 -07:00
Andrew Kelley
e5b46eab3b std: dwarf namespace reorg
std.debug.Dwarf is the parsing/decoding logic. std.dwarf remains the
unopinionated types and bits alone.

If you look at this diff you can see a lot less redundancy in
namespaces.
2024-08-01 13:56:12 -07:00