Only pass --[no-]gc-sections if linker is GNU ld.
Fixes a regression from #84468 where linking now fails with solaris linkers. LinkerFlavor::Gcc does not always mean GNU ld specifically. And in the case of at least the solaris ld in illumos, that flag is unrecognized and will cause the linking step to fail.
Even though removing the `is_like_solaris` branch from `gc_sections` in #84468 made sense as `-z ignore/record` are more analogous to the `--[no-]-as-needed` flags, it inadvertently caused solaris linkers to be passed the `--gc-sections` flag. So let's just change it to be more explicit about when we pass those flags.
Remove CrateNum parameter for queries that only work on local crate
The pervasive `CrateNum` parameter is a remnant of the multi-crate rustc idea.
Using `()` as query key in those cases avoids having to worry about the validity of the query key.
Use the object crate for metadata reading
This allows sharing the metadata reader between cg_llvm, cg_clif and other codegen backends.
This is not currently useful for rlib reading with cg_spirv ([rust-gpu](https://github.com/EmbarkStudios/rust-gpu/)) as it uses tar rather than ar as .rlib format, but it is useful for dylib reading required for loading proc macros. (cc `@eddyb)`
The object crate is already trusted as dependency of libstd through backtrace. As far as I know it supports reading all object file formats used by targets for which we support rust dylibs with crate metadata, but I am not certain. If this happens to not be the case, I could keep using LLVM for reading dylib metadata.
Marked as WIP for a perf run and as it is based on #83637.
LinkerFlavor::Gcc does not always mean GNU ld specifically. And in the
case of at least the solaris ld in illumos, that flag is unrecognized
and will cause the linking step to fail.
Under some conditions, the toolchain will produce a sequence of linker
arguments that result in a NEEDED list that puts libc before libgcc_s;
e.g.,
[0] NEEDED 0x2046ba libc.so.1
[1] NEEDED 0x204723 libm.so.2
[2] NEEDED 0x204736 libsocket.so.1
[3] NEEDED 0x20478b libumem.so.1
[4] NEEDED 0x204763 libgcc_s.so.1
Both libc and libgcc_s provide an unwinder implementation, but libgcc_s
provides some extra symbols upon which Rust directly depends. If libc
is first in the NEEDED list we will find some of those symbols in libc
but others in libgcc_s, resulting in undefined behaviour as the two
implementations do not use compatible interior data structures.
This solution is not perfect, but is the simplest way to produce correct
binaries on illumos for now.
Fix#84467 linker_args with --target=sparcv9-sun-solaris
Trying to cross-compile for sparcv9-sun-solaris
getting a error message for -zignore
Introduced when -z -ignore was seperated here
22d0ab0
No formatting done
Reproduce
``` bash
rustup target add sparcv9-sun-solaris
cargo new --bin hello && cd hello && cargo run --target=sparcv9-sun-solaris
```
config.toml
[target.sparcv9-sun-solaris]
linker = "gcc"
This commit implements both the native linking modifiers infrastructure
as well as an initial attempt at the individual modifiers from the RFC.
It also introduces a feature flag for the general syntax along with
individual feature flags for each modifier.
Moved -z ignore to add_as_needed
Trying to cross-compile for sparcv9-sun-solaris
getting an error message for -zignore
Introduced when -z -ignore was separated here
22d0ab0
No formatting done
Reproduce
``` bash
rustup target add sparcv9-sun-solaris
cargo new --bin hello && cd hello && cargo run --target=sparcv9-sun-solaris
```
config.toml
[target.sparcv9-sun-solaris]
linker = "gcc"
Use FromStr trait for number option parsing
Replace `parse_uint` with generic `parse_number` based on `FromStr`.
Use it for parsing inlining threshold to avoid casting later.
Add an Mmap wrapper to rustc_data_structures
This wrapper implements StableAddress and falls back to directly reading the file on wasm32.
Taken from #83640, which I will close due to the perf regression.
Adjusted LLVM codegen for code compiled with `-Zinstrument-coverage` to
address multiple, somewhat related issues.
Fixed a significant flaw in prior coverage solution: Every counter
generated a new counter variable, but there should have only been one
counter variable per function. This appears to have bloated .profraw
files significantly. (For a small program, it increased the size by
about 40%. I have not tested large programs, but there is anecdotal
evidence that profraw files were way too large. This is a good fix,
regardless, but hopefully it also addresses related issues.
Fixes: #82144
Invalid LLVM coverage data produced when compiled with -C opt-level=1
Existing tests now work up to at least `opt-level=3`. This required a
detailed analysis of the LLVM IR, comparisons with Clang C++ LLVM IR
when compiled with coverage, and a lot of trial and error with codegen
adjustments.
The biggest hurdle was figuring out how to continue to support coverage
results for unused functions and generics. Rust's coverage results have
three advantages over Clang's coverage results:
1. Rust's coverage map does not include any overlapping code regions,
making coverage counting unambiguous.
2. Rust generates coverage results (showing zero counts) for all unused
functions, including generics. (Clang does not generate coverage for
uninstantiated template functions.)
3. Rust's unused functions produce minimal stubbed functions in LLVM IR,
sufficient for including in the coverage results; while Clang must
generate the complete LLVM IR for each unused function, even though
it will never be called.
This PR removes the previous hack of attempting to inject coverage into
some other existing function instance, and generates dedicated instances
for each unused function. This change, and a few other adjustments
(similar to what is required for `-C link-dead-code`, but with lower
impact), makes it possible to support LLVM optimizations.
Fixes: #79651
Coverage report: "Unexecuted instantiation:..." for a generic function
from multiple crates
Fixed by removing the aforementioned hack. Some "Unexecuted
instantiation" notices are unavoidable, as explained in the
`used_crate.rs` test, but `-Zinstrument-coverage` has new options to
back off support for either unused generics, or all unused functions,
which avoids the notice, at the cost of less coverage of unused
functions.
Fixes: #82875
Invalid LLVM coverage data produced with crate brotli_decompressor
Fixed by disabling the LLVM function attribute that forces inlining, if
`-Z instrument-coverage` is enabled. This attribute is applied to
Rust functions with `#[inline(always)], and in some cases, the forced
inlining breaks coverage instrumentation and reports.
