These are really answering questions about the Zig compiler's capacity to
provide a libc/libc++ implementation. As such, std.zig.target seems like a more
fitting place for these.
Make shared_objects a StringArrayHashMap so that deduping does not
need to happen in flush. That deduping code also was using an O(N^2)
algorithm, which is not allowed in this codebase. There is another
violation of this rule in resolveSymbols but this commit does not
address it.
This required reworking shared object parsing, breaking it into
independent components so that we could access soname earlier.
Shared object parsing had a few problems that I noticed and fixed in
this commit:
* Many instances of incorrect use of align(1).
* `shnum * @sizeOf(elf.Elf64_Shdr)` can overflow based on user data.
* `@divExact` can cause illegal behavior based on user data.
* Strange versyms logic that wasn't present in mold nor lld. The logic
was not commented and there is no git blame information in ziglang/zig
nor kubkon/zld. I changed it to match mold and lld instead.
* Use of ArrayList for slices of memory that are never resized.
* finding DT_VERDEFNUM in a different loop than finding DT_SONAME.
Ultimately I think we should follow mold's lead and ignore this
integer, relying on null termination instead.
* Doing logic based on VER_FLG_BASE rather than ignoring it like mold
and LLD do. No comment explaining why the behavior is different.
* Mutating the original ELF symbols rather than only storing the mangled
name on the new Symbol struct.
I noticed something that I didn't try to address in this commit: Symbol
stores a lot of redundant information that is already present in the ELF
symbols. I suspect that the codebase could benefit from reworking Symbol
to not store redundant information.
Additionally:
* Add some type safety to std.elf.
* Eliminate 1-3 file system reads for determining the kind of input
files, by taking advantage of file name extension and handling error
codes properly.
* Move more error handling methods to link.Diags and make them
infallible and thread-safe
* Make the data dependencies obvious in the parameters of
parseSharedObject. It's now clear that the first two steps (Header and
Parsed) can be done during the main Compilation pipeline, rather than
waiting for flush().
Embrace the Path abstraction, doing more operations based on directory
handles rather than absolute file paths. Most of the diff noise here
comes from this one.
Fix sorting of crtbegin/crtend atoms. Previously it would look at all
path components for those strings.
Make the C runtime path detection partially a pure function, and move
some logic to glibc.zig where it belongs.
The compiler actually doesn't need any functional changes for this: Sema
does reification based on the tag indices of `std.builtin.Type` already!
So, no zig1.wasm update is necessary.
This change is necessary to disallow name clashes between fields and
decls on a type, which is a prerequisite of #9938.
A compilation build step for which the binary is not required could not
be compiled previously. There were 2 issues that caused this:
- The compiler communicated only the results of the emitted binary and
did not properly communicate the result if the binary was not emitted.
This is fixed by communicating the final hash of the artifact path (the
hash of the corresponding /o/<hash> directory) and communicating this
instead of the entire path. This changes the zig build --listen protocol
to communicate hashes instead of paths, and emit_bin_path is accordingly
renamed to emit_digest.
- There was an error related to the default llvm object path when
CacheUse.Whole was selected. I'm not really sure why this didn't manifest
when the binary is also emitted.
This was fixed by improving the path handling related to flush() and
emitLlvmObject().
In general, this commit also improves some of the path handling throughout
the compiler and standard library.
Simplifies code in docs creation where we used `std.tar.output.Header`.
Writer uses that Header internally and provides higher level interface.
Updates checksum on write, handles long file names, allows setting mtime and file permission mode. Provides handy interface for passing `Dir.WalkerEntry`.
Using --watch I noticed a couple of issues with my initial attempt. 1) The index I used as 'completion key' was not stable over time, when directories are being added/removed the key no longer corresponds with the intended dir. 2) There exists a race condition in which we receive a completion notification for a directory that was removed. My solution is to generate a key value and associate it with each Directory.
* Upgrade from u8 to usize element types.
- WebAssembly assumes u64. It should probably try to be target-aware
instead.
* Move the covered PC bits to after the header so it goes on the same
page with the other rapidly changing memory (the header stats).
depends on the semantics of accepted proposal #19755closes#20994
* libfuzzer: track unique runs instead of deduplicated runs
- easier for consumers to notice when to recheck the covered bits.
* move common definitions to `std.Build.Fuzz.abi`.
build runner sends all the information needed to fuzzer web interface
client needed in order to display inline coverage information along with
source code.
* libfuzzer: close file after mmap
* fuzzer/main.js: connect with EventSource and debug dump the messages.
currently this prints how many fuzzer runs have been attempted to
console.log.
* extract some `std.debug.Info` logic into `std.debug.Coverage`.
Prepares for consolidation across multiple different executables which
share source files, and makes it possible to send all the
PC/SourceLocation mapping data with 4 memcpy'd arrays.
* std.Build.Fuzz:
- spawn a thread to watch the message queue and signal event
subscribers.
- track coverage map data
- respond to /events URL with EventSource messages on a timer
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.
* new .zig-cache subdirectory: 'v'
- stores coverage information with filename of hash of PCs that want
coverage. This hash is a hex encoding of the 64-bit coverage ID.
* build runner
* fixed bug in file system inputs when a compile step has an
overridden zig_lib_dir field set.
* set some std lib options optimized for the build runner
- no side channel mitigations
- no Transport Layer Security
- no crypto fork safety
* add a --port CLI arg for choosing the port the fuzzing web interface
listens on. it defaults to choosing a random open port.
* introduce a web server, and serve a basic single page application
- shares wasm code with autodocs
- assets are created live on request, for convenient development
experience. main.wasm is properly cached if nothing changes.
- sources.tar comes from file system inputs (introduced with the
`--watch` feature)
* receives coverage ID from test runner and sends it on a thread-safe
queue to the WebServer.
* test runner
- takes a zig cache directory argument now, for where to put coverage
information.
- sends coverage ID to parent process
* fuzzer
- puts its logs (in debug mode) in .zig-cache/tmp/libfuzzer.log
- computes coverage_id and makes it available with
`fuzzer_coverage_id` exported function.
- the memory-mapped coverage file is now namespaced by the coverage id
in hex encoding, in `.zig-cache/v`
* tokenizer
- add a fuzz test to check that several properties are upheld
Deprecates std.fs.atomicSymLink and removes the allocator requirement
from the new std.fs.Dir.atomicSymLink. Replaces the two usages of this
within std.
I did not include the TODOs from the original code that were based
off of `switch (err) { ..., else => return err }` not having correct
inference that cases handled in `...` are impossible in the error
union return type because these are not specified in many places but
I can add them back if wanted.
Thank you @squeek502 for help with fixing buffer overflows!
The flag makes compiler_rt and libfuzzer be in debug mode.
Also:
* fuzzer: override debug logs and disable debug logs for frequently
called functions
* std.Build.Fuzz: fix bug of rerunning the old unit test binary
* report errors from rebuilding the unit tests better
* link.Elf: additionally add tsan lib and fuzzer lib to the hash
This flag makes the build runner rebuild unit tests after the pipeline
finishes, if it finds any unit tests.
I did not make this integrate with file system watching yet.
The test runner is updated to detect which tests are fuzz tests.
Run step is updated to track which test indexes are fuzz tests.
* Add -f(no-)sanitize-coverage-trace-pc-guard CLI flag which defaults to
off. This value lowers to TracePCGuard = true (LLVM backend) and -Xclang
-fsanitize-coverage-trace-pc-guard. These settings are not
automatically included with -ffuzz.
* Add `Build.Step.Compile` flag for sanitize_coverage_trace_pc_guard
with appropriate documentation.
* Add `zig cc` integration for the respective flags.
* Avoid crashing in ELF linker code when -ffuzz -femit-llvm-ir used
together.
