I've run into this footgun enough times, nearly every time I want
`ensureUnusedCapacity`, not `ensureCapacity`. This commit deprecates
`ensureCapacity` in favor of `ensureTotalCapacity` and introduces
`ensureUnusedCapacity`.
* AstGen: represent compile errors in ZIR rather than returning
`error.AnalysisFail`.
* ZIR: remove decl_ref and decl_val instructions. These are replaced by
`decl_ref_named` and `decl_val_named`, respectively, which will
probably get renamed in the future to the instructions that were just
deleted.
* AstGen: implement `@This()`, `@fence()`, `@returnAddress()`, and
`@src()`.
* AstGen: struct_decl improved to support fields_len=0 but have decls.
* AstGen: fix missing null bytes after compile error messages.
* SrcLoc: no longer depend on `Decl`. Instead have an explicit field
`parent_decl_node` which is an absolute AST Node index.
* Module: `failed_files` table can have null value, in which case the
key, which is a `*Scope.File`, will have ZIR errors in it.
* ZIR: implement text rendering of struct decls.
* CLI: introduce debug_usage and `zig astgen` command which is enabled
when the compiler is built in debug mode.
This was also an experiment to see if it were easier to implement a new
feature when using the instruction encoder.
Verdict: It's not that much easier, but I think it's certainly much more
readable, because the description of the Instruction annotates what each
field means. Right now, precise knowledge of x86_64 instructions is
still required because things like when to set the 64-bit flag, how to
read x86_64 instruction references, etc. are still not automatically
done for you.
In the future, this interface might make it sligtly easier to write an
assembler for x86_64, by abstracting the bit-fiddling aspects of
instruction encoding.
From my very cursory reading, it seems that the register manager doesn't
distinguish between registers that are physically the same but have
different sizes.
In that case, this means that during codegen, we can't rely on
`reg.size()` when determining the width of the operations we have to
perform. Instead, we must use some form of `ty.abiSize(self.target.*)`
to determine the size of the type we're operating with. If this size is
64 bits, then we should enable 64-bit operation.
This fixed a bug in the codegen for spilling instructions, which was
overwriting the previous stack entry with zeroes. See the modified test
case in this commit.
There are parts of it that I didn't modify because the byte
representation was important (e.g. we need to know what the exact
byte position where we store the address into the offset table is)
In std.meta.cast when casting to an enum type from an integer type, first
do a C-style cast from the source value to the tag type of the enum.
This ensures that we don't get an error due to the source value not being
representable by the enum.
In transCCast() use std.meta.cast instead of directly emitting the cast
operation since the enum's underlying type may not be known at translation
time due to an MSVC bug, see https://github.com/ziglang/zig/issues/8003Fixes#6011
See #8516.
* AstGen is now done on whole files at once rather than per Decl.
* Introduce a new wait group for AstGen tasks. `performAllTheWork`
waits for all AstGen tasks to be complete before doing Sema,
single-threaded.
- The C object compilation tasks are moved to be spawned after
AstGen, since they only need to complete by the end of
the function.
With this commit, the codebase compiles, but much more reworking is
needed to get things back into a useful state.
