These names aren't matching any formal specification; they're mostly
just ripped from LLVM code. Therefore, we should definitely follow Zig
naming conventions here.
Most of these changes seem like improvements. The PDB thing had a TODO
saying it used to crash; I anticipate it works now, we'll see what CI
does.
The `std.os.uefi` field renames are a notable breaking change.
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.
Grepping for `NO_THUMB` in glibc suggests that glibc does not actually support
pure Thumb-2 mode. This is the mode that is implied by these target triples;
mixed Arm/Thumb mode should just use the regular `arm*-linux-gnueabi*` triples.
Implements the accepted proposal to introduce `@branchHint`. This
builtin is permitted as the first statement of a block if that block is
the direct body of any of the following:
* a function (*not* a `test`)
* either branch of an `if`
* the RHS of a `catch` or `orelse`
* a `switch` prong
* an `or` or `and` expression
It lowers to the ZIR instruction `extended(branch_hint(...))`. When Sema
encounters this instruction, it sets `sema.branch_hint` appropriately,
and `zirCondBr` etc are expected to reset this value as necessary. The
state is on `Sema` rather than `Block` to make it automatically
propagate up non-conditional blocks without special handling. If
`@panic` is reached, the branch hint is set to `.cold` if none was
already set; similarly, error branches get a hint of `.unlikely` if no
hint is explicitly provided. If a condition is comptime-known, `cold`
hints from the taken branch are allowed to propagate up, but other hints
are discarded. This is because a `likely`/`unlikely` hint just indicates
the direction this branch is likely to go, which is redundant
information when the branch is known at comptime; but `cold` hints
indicate that control flow is unlikely to ever reach this branch,
meaning if the branch is always taken from its parent, then the parent
is also unlikely to ever be reached.
This branch information is stored in AIR `cond_br` and `switch_br`. In
addition, `try` and `try_ptr` instructions have variants `try_cold` and
`try_ptr_cold` which indicate that the error case is cold (rather than
just unlikely); this is reachable through e.g. `errdefer unreachable` or
`errdefer @panic("")`.
A new API `unwrapSwitch` is introduced to `Air` to make it more
convenient to access `switch_br` instructions. In time, I plan to update
all AIR instructions to be accessed via an `unwrap` method which returns
a convenient tagged union a la `InternPool.indexToKey`.
The LLVM backend lowers branch hints for conditional branches and
switches as follows:
* If any branch is marked `unpredictable`, the instruction is marked
`!unpredictable`.
* Any branch which is marked as `cold` gets a
`llvm.assume(i1 true) [ "cold"() ]` call to mark the code path cold.
* If any branch is marked `likely` or `unlikely`, branch weight metadata
is attached with `!prof`. Likely branches get a weight of 2000, and
unlikely branches a weight of 1. In `switch` statements, un-annotated
branches get a weight of 1000 as a "middle ground" hint, since there
could be likely *and* unlikely *and* un-annotated branches.
For functions, a `cold` hint corresponds to the `cold` function
attribute, and other hints are currently ignored -- as far as I can tell
LLVM doesn't really have a way to lower them. (Ideally, we would want
the branch hint given in the function to propagate to call sites.)
The compiler and standard library do not yet use this new builtin.
Resolves: #21148
Implements the base that should usually work that is
- Check LD_LIBRARY_PATH if the binary is no setuid setgid binary
- Check /lib, /usr/lib, in that order
The missing parts are:
- DT_RPATH and DT_RUNPATH handling from the calling executable
- Reading /etc/ld.so.cache
For more details check man page of dlopen(3)
This reverts commit cb5a6be41ae0efc30d0b59a41b0763db966e5bf4.
I deeply apologize for the churn.
This change is problematic given that we do not have ranged integers
(yet? see #3806).
In the meantime, this type needs to be `usize`, matching the length and
index types for all std lib data structures.
Users who want to save memory should not use heap-allocated BoundedArray
values, since it is inherently memory-inefficient. Use a different
memory layout instead.
If #3806 is accepted and implemented, the length value can become an
integer with the appropriate range, without the footgun. If that
proposal is not accepted, len type will remain a usize.
Ensures that all runned command are visible when using `--verbose` flag,
for example `pkg-config` from Step.Compile or `git describe` from build.zig.
Signed-off-by: Eric Joldasov <bratishkaerik@landless-city.net>
These are fundamentally incapable of producing accurate information for reasons
I've laid out in #20771. Since our only use of these functions is to check that
object files have the correct machine type, and since #21020 made
`std.Target.to{Coff,Elf}Machine()` more accurate, just switch these checks over
to that and compare the machine type tags instead.
Closes#20771.
* reduce iteration cost by not tracking unused entries
* avoid emitting unused abbrevs to `.debug_abbrev`
* get the compiler executable passing `llvm-dwarfdump --verify`
* make it possible to skip `.debug_line` padding much more quickly
