The backing allocator may return a block that's actually bigger than the
one required by the user, use the correct quantity when keeping track of
the allocation ceiling.
Closes#6049
This is a temporary debugging trick you can use to turn segfaults into more helpful
logged error messages with stack trace details. The downside is that every allocation
will be leaked!
`std.builtin.StackTrace` gains a `format` function.
GeneralPurposeAllocator uses `std.log.err` instead of directly printing
to stderr. Some errors are recoverable.
The test runner is modified to fail the test run if any log messages of
"err" or worse severity are encountered.
self-hosted is modified to always print log messages of "err" severity
or worse even if they have not been explicitly enabled.
This makes GeneralPurposeAllocator available on the freestanding target.
We don't pass no-omit-frame-pointer in release safe by default, so it
also makes sense to not try to collect stack trace frames by default in
release safe mode.
This makes `@returnAddress()` return 0 for WebAssembly (when not using
the Emscripten OS) and avoids trying to capture stack traces for the
general purpose allocator on that target.
The high level Allocator interface API functions will now do a
`@returnAddress()` so that stack traces captured by allocator
implementations have a return address that does not include the
Allocator overhead functions. This makes `4` a more reasonable default
for how many stack frames to capture.
* std.Mutex API is improved to not have init() deinit(). This API is
designed to support static initialization and does not require any
resource cleanup. This also happens to work around some kind of
stage1 behavior that wasn't letting the new allocator mutex code
get compiled.
* the general purpose allocator now returns a bool from deinit()
which tells if there were any leaks. This value is used by the test
runner to fail the tests if there are any.
* self-hosted compiler is updated to use the general purpose allocator
when not linking against libc.
`std.GeneralPurposeAllocator` is now available. It is a function that
takes a configuration struct (with default field values) and returns an
allocator. There is a detailed description of this allocator in the
doc comments at the top of the new file.
The main feature of this allocator is that it is *safe*. It
prevents double-free, use-after-free, and detects leaks.
Some deprecation compile errors are removed.
The Allocator interface gains `old_align` as a new parameter to
`resizeFn`. This is useful to quickly look up allocations.
`std.heap.page_allocator` is improved to use mmap address hints to avoid
obtaining the same virtual address pages when unmapping and mapping
pages. The new general purpose allocator uses the page allocator as its
backing allocator by default.
`std.testing.allocator` is replaced with usage of this new allocator,
which does leak checking, and so the LeakCheckAllocator is retired.
stage1 is improved so that the `@typeInfo` of a pointer has a lazy value
for the alignment of the child type, to avoid false dependency loops
when dealing with pointers to async function frames.
The `std.mem.Allocator` interface is refactored to be in its own file.
`std.Mutex` now exposes the dummy mutex with `std.Mutex.Dummy`.
This allocator is great for debug mode, however it needs some work to
have better performance in release modes. The next step will be setting
up a series of tests in ziglang/gotta-go-fast and then making
improvements to the implementation.
