* Deleted decls are deleted; unused decls are also detected as deleted.
Cycles are not yet detected.
* Re-analysis is smarter and will not cause a re-analysis of dependants
when only a function body is changed.
The binary file abstraction changed its struct named "Decl" to
"TextBlock" and it now represents an allocated slice of memory in
the .text section. It has two new fields: prev and next, making it
a linked list node. This allows a TextBlock to find its neighbors.
The ElfFile struct now has free_list and last_text_block fields.
Doc comments for free_list are reproduced here:
A list of text blocks that have surplus capacity. This list can have false
positives, as functions grow and shrink over time, only sometimes being added
or removed from the freelist.
A text block has surplus capacity when its overcapacity value is greater than
minimum_text_block_size * alloc_num / alloc_den. That is, when it has so
much extra capacity, that we could fit a small new symbol in it, itself with
ideal_capacity or more.
Ideal capacity is defined by size * alloc_num / alloc_den.
Overcapacity is measured by actual_capacity - ideal_capacity. Note that
overcapacity can be negative. A simple way to have negative overcapacity is to
allocate a fresh text block, which will have ideal capacity, and then grow it
by 1 byte. It will then have -1 overcapacity.
The last_text_block keeps track of the end of the .text section.
Allocation, freeing, and resizing decls are all now more sophisticated,
and participate in the virtual address allocation scheme. There is no
longer the possibility for virtual address collisions.
However there does not appear to be an x86 encoding for calling an
immediate address. So there's no point of setting this up. We should
just emit an indirect call to the got addr.
* add TypedValue.Managed which represents a Type, a Value, and some
kind of memory management strategy.
* introduce an analysis queue
* flesh out how incremental compilation works with respect to exports
* ir.text.Module is only capable of one error message during parsing
* link.zig no longer has a decl table map and instead has structs that
exist directly on ir.Module.Decl and ir.Module.Export
* implement primitive .text block allocation
* implement linker code for updating Decls and Exports
* implement null Type
Some supporting std lib changes:
* add std.ArrayList.appendSliceAssumeCapacity
* add std.fs.File.copyRange and copyRangeAll
* fix std.HashMap having modification safety on in ReleaseSmall builds
* add std.HashMap.putAssumeCapacityNoClobber
* introduce std.ArrayListUnmanaged for when you have the allocator
stored elsewhere
* move std.heap.ArenaAllocator implementation to its own file. extract
the main state into std.heap.ArenaAllocator.State, which can be
stored as an alternative to storing the entire ArenaAllocator, saving
24 bytes per ArenaAllocator on 64 bit targets.
* std.LinkedList.Node pointer field now defaults to being null
initialized.
* Rework self-hosted compiler Package API
* Delete almost all the bitrotted self-hosted compiler code. The only bit
rotted code left is in main.zig and compilation.zig
* Add call instruction to ZIR
* self-hosted compiler ir API and link API are reworked to support
a long-running compiler that incrementally updates declarations
* Introduce the concept of scopes to ZIR semantic analysis
* ZIR text format supports referencing named decls that are declared
later in the file
* Figure out how memory management works for the long-running compiler
and incremental compilation. The main roots are top level
declarations. There is a table of decls. The key is a cryptographic
hash of the fully qualified decl name. Each decl has an arena
allocator where all of the memory related to that decl is stored.
Each code block has its own arena allocator for the lifetime of
the block. Values that want to survive when going out of scope in
a block must get copied into the outer block. Finally, values must
get copied into the Decl arena to be long-lived.
* Delete the unused MemoryCell struct. Instead, comptime pointers are
based on references to Decl structs.
* Figure out how caching works. Each Decl will store a set of other
Decls which must be recompiled when it changes.
This branch is still work-in-progress; this commit breaks the build.
Jonathan S writes:
On common systems with a 022 umask, this will still result in a
file created with 755 permissions, but it works appropriately if the
system is configured more leniently. (As another data point, C's fopen
seems to open files with the 666 mode.)
This new name (and the fact that it is a function returning a type) will
make it more clear which use cases are better suited for ArrayList and
which are better suited for ArrayListSentineled.
Also for consistency with ArrayList,
* `append` => `appendSlice`
* `appendByte` => `append`
Thanks daurnimator for pointing out the confusion of std.Buffer.
closes#4682
The self-hosted compiler is still bit rotted and still not compiling
successfully yet. I have a more serious rework of the code in a
different branch.
* re-introduce `std.build.Target` which is distinct from `std.Target`.
`std.build.Target` wraps `std.Target` so that it can be annotated as
"the native target" or an explicitly specified target.
* `std.Target.Os` is moved to `std.Target.Os.Tag`. The former is now a
struct which has the tag as well as version range information.
* `std.elf` gains some more ELF header constants.
* `std.Target.parse` gains the ability to parse operating system
version ranges as well as glibc version.
* Added `std.Target.isGnuLibC()`.
* self-hosted dynamic linker detection and glibc version detection.
This also adds the improved logic using `/usr/bin/env` rather than
invoking the system C compiler to find the dynamic linker when zig
is statically linked. Related: #2084
Note: this `/usr/bin/env` code is work-in-progress.
* `-target-glibc` CLI option is removed in favor of the new `-target`
syntax. Example: `-target x86_64-linux-gnu.2.27`
closes#1907
The new plan to support hobby operating systems is #3784.
And what kind of name is "Zen" anyway? There's already a
[Zen programming language](http://zenlang.sourceforge.net/)
and that's just confusing.
this also deletes C string literals from the language, and then makes
the std lib changes and compiler changes necessary to get the behavior
tests and std lib tests passing again.
Andrew Kelley
Michaël Larouche
LemonBoy
David Cao
Vexu
Vexu