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rustc_target: Refactor internal linker flavors

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In accordance with the design from https://github.com/rust-lang/rust/pull/96827#issuecomment-1208441595
This commit is contained in:
Vadim Petrochenkov
2022-08-06 21:08:46 +03:00
parent 4bd30785eb
commit 572b6a9c60
104 changed files with 569 additions and 438 deletions
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229
compiler/rustc_target/src/spec/mod.rs
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@@ -90,17 +90,73 @@ mod windows_msvc_base;
mod windows_uwp_gnu_base;
mod windows_uwp_msvc_base;
/// Linker is called through a C/C++ compiler.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum Cc {
Yes,
No,
}
/// Linker is LLD.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum Lld {
Yes,
No,
}
/// All linkers have some kinds of command line interfaces and rustc needs to know which commands
/// to use with each of them. So we cluster all such interfaces into a (somewhat arbitrary) number
/// of classes that we call "linker flavors".
///
/// Technically, it's not even necessary, we can nearly always infer the flavor from linker name
/// and target properties like `is_like_windows`/`is_like_osx`/etc. However, the PRs originally
/// introducing `-Clinker-flavor` (#40018 and friends) were aiming to reduce this kind of inference
/// and provide something certain and explicitly specified instead, and that design goal is still
/// relevant now.
///
/// The second goal is to keep the number of flavors to the minimum if possible.
/// LLD somewhat forces our hand here because that linker is self-sufficent only if its executable
/// (`argv[0]`) is named in specific way, otherwise it doesn't work and requires a
/// `-flavor LLD_FLAVOR` argument to choose which logic to use. Our shipped `rust-lld` in
/// particular is not named in such specific way, so it needs the flavor option, so we make our
/// linker flavors sufficiently fine-grained to satisfy LLD without inferring its flavor from other
/// target properties, in accordance with the first design goal.
///
/// The first component of the flavor is tightly coupled with the compilation target,
/// while the `Cc` and `Lld` flags can vary withing the same target.
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum LinkerFlavor {
Gcc,
Ld,
Lld(LldFlavor),
Msvc,
/// Unix-like linker with GNU extensions (both naked and compiler-wrapped forms).
/// Besides similar "default" Linux/BSD linkers this also includes Windows/GNU linker,
/// which is somewhat different because it doesn't produce ELFs.
Gnu(Cc, Lld),
/// Unix-like linker for Apple targets (both naked and compiler-wrapped forms).
/// Extracted from the "umbrella" `Unix` flavor due to its corresponding LLD flavor.
Darwin(Cc, Lld),
/// Unix-like linker for Wasm targets (both naked and compiler-wrapped forms).
/// Extracted from the "umbrella" `Unix` flavor due to its corresponding LLD flavor.
/// Non-LLD version does not exist, so the lld flag is currently hardcoded here.
WasmLld(Cc),
/// Basic Unix-like linker for "any other Unix" targets (Solaris/illumos, L4Re, MSP430, etc),
/// possibly with non-GNU extensions (both naked and compiler-wrapped forms).
/// LLD doesn't support any of these.
Unix(Cc),
/// MSVC-style linker for Windows and UEFI, LLD supports it.
Msvc(Lld),
/// Emscripten Compiler Frontend, a wrapper around `WasmLld(Cc::Yes)` that has a different
/// interface and produces some additional JavaScript output.
EmCc,
// Below: other linker-like tools with unique interfaces for exotic targets.
/// Linker tool for BPF.
Bpf,
/// Linker tool for Nvidia PTX.
Ptx,
}
/// Linker flavors available externally through command line (`-Clinker-flavor`)
/// or json target specifications.
/// FIXME: This set has accumulated historically, bring it more in line with the internal
/// linker flavors (`LinkerFlavor`).
#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)]
pub enum LinkerFlavorCli {
Gcc,
@@ -148,12 +204,32 @@ impl ToJson for LldFlavor {
}
impl LinkerFlavor {
pub fn from_cli(cli: LinkerFlavorCli) -> LinkerFlavor {
pub fn from_cli(cli: LinkerFlavorCli, target: &TargetOptions) -> LinkerFlavor {
Self::from_cli_impl(cli, target.linker_flavor.lld_flavor(), target.linker_flavor.is_gnu())
}
/// The passed CLI flavor is preferred over other args coming from the default target spec,
/// so this function can produce a flavor that is incompatible with the current target.
/// FIXME: Produce errors when `-Clinker-flavor` is set to something incompatible
/// with the current target.
fn from_cli_impl(cli: LinkerFlavorCli, lld_flavor: LldFlavor, is_gnu: bool) -> LinkerFlavor {
match cli {
LinkerFlavorCli::Gcc => LinkerFlavor::Gcc,
LinkerFlavorCli::Ld => LinkerFlavor::Ld,
LinkerFlavorCli::Lld(lld_flavor) => LinkerFlavor::Lld(lld_flavor),
LinkerFlavorCli::Msvc => LinkerFlavor::Msvc,
LinkerFlavorCli::Gcc => match lld_flavor {
LldFlavor::Ld if is_gnu => LinkerFlavor::Gnu(Cc::Yes, Lld::No),
LldFlavor::Ld64 => LinkerFlavor::Darwin(Cc::Yes, Lld::No),
LldFlavor::Wasm => LinkerFlavor::WasmLld(Cc::Yes),
LldFlavor::Ld | LldFlavor::Link => LinkerFlavor::Unix(Cc::Yes),
},
LinkerFlavorCli::Ld => match lld_flavor {
LldFlavor::Ld if is_gnu => LinkerFlavor::Gnu(Cc::No, Lld::No),
LldFlavor::Ld64 => LinkerFlavor::Darwin(Cc::No, Lld::No),
LldFlavor::Ld | LldFlavor::Wasm | LldFlavor::Link => LinkerFlavor::Unix(Cc::No),
},
LinkerFlavorCli::Lld(LldFlavor::Ld) => LinkerFlavor::Gnu(Cc::No, Lld::Yes),
LinkerFlavorCli::Lld(LldFlavor::Ld64) => LinkerFlavor::Darwin(Cc::No, Lld::Yes),
LinkerFlavorCli::Lld(LldFlavor::Wasm) => LinkerFlavor::WasmLld(Cc::No),
LinkerFlavorCli::Lld(LldFlavor::Link) => LinkerFlavor::Msvc(Lld::Yes),
LinkerFlavorCli::Msvc => LinkerFlavor::Msvc(Lld::No),
LinkerFlavorCli::Em => LinkerFlavor::EmCc,
LinkerFlavorCli::BpfLinker => LinkerFlavor::Bpf,
LinkerFlavorCli::PtxLinker => LinkerFlavor::Ptx,
@@ -162,15 +238,40 @@ impl LinkerFlavor {
fn to_cli(self) -> LinkerFlavorCli {
match self {
LinkerFlavor::Gcc => LinkerFlavorCli::Gcc,
LinkerFlavor::Ld => LinkerFlavorCli::Ld,
LinkerFlavor::Lld(lld_flavor) => LinkerFlavorCli::Lld(lld_flavor),
LinkerFlavor::Msvc => LinkerFlavorCli::Msvc,
LinkerFlavor::Gnu(Cc::Yes, _)
| LinkerFlavor::Darwin(Cc::Yes, _)
| LinkerFlavor::WasmLld(Cc::Yes)
| LinkerFlavor::Unix(Cc::Yes) => LinkerFlavorCli::Gcc,
LinkerFlavor::Gnu(_, Lld::Yes) => LinkerFlavorCli::Lld(LldFlavor::Ld),
LinkerFlavor::Darwin(_, Lld::Yes) => LinkerFlavorCli::Lld(LldFlavor::Ld64),
LinkerFlavor::WasmLld(..) => LinkerFlavorCli::Lld(LldFlavor::Wasm),
LinkerFlavor::Gnu(..) | LinkerFlavor::Darwin(..) | LinkerFlavor::Unix(..) => {
LinkerFlavorCli::Ld
}
LinkerFlavor::Msvc(Lld::Yes) => LinkerFlavorCli::Lld(LldFlavor::Link),
LinkerFlavor::Msvc(..) => LinkerFlavorCli::Msvc,
LinkerFlavor::EmCc => LinkerFlavorCli::Em,
LinkerFlavor::Bpf => LinkerFlavorCli::BpfLinker,
LinkerFlavor::Ptx => LinkerFlavorCli::PtxLinker,
}
}
pub fn lld_flavor(self) -> LldFlavor {
match self {
LinkerFlavor::Gnu(..)
| LinkerFlavor::Unix(..)
| LinkerFlavor::EmCc
| LinkerFlavor::Bpf
| LinkerFlavor::Ptx => LldFlavor::Ld,
LinkerFlavor::Darwin(..) => LldFlavor::Ld64,
LinkerFlavor::WasmLld(..) => LldFlavor::Wasm,
LinkerFlavor::Msvc(..) => LldFlavor::Link,
}
}
pub fn is_gnu(self) -> bool {
matches!(self, LinkerFlavor::Gnu(..))
}
}
macro_rules! linker_flavor_cli_impls {
@@ -1258,16 +1359,11 @@ pub struct TargetOptions {
/// Linker to invoke
pub linker: Option<StaticCow<str>>,
/// Default linker flavor used if `-C linker-flavor` or `-C linker` are not passed
/// on the command line. Defaults to `LinkerFlavor::Gcc`.
/// on the command line. Defaults to `LinkerFlavor::Gnu(Cc::Yes, Lld::No)`.
pub linker_flavor: LinkerFlavor,
linker_flavor_json: LinkerFlavorCli,
/// LLD flavor used if `lld` (or `rust-lld`) is specified as a linker
/// without clarifying its flavor in any way.
/// FIXME: Merge this into `LinkerFlavor`.
pub lld_flavor: LldFlavor,
/// Whether the linker support GNU-like arguments such as -O. Defaults to true.
/// FIXME: Merge this into `LinkerFlavor`.
pub linker_is_gnu: bool,
lld_flavor_json: LldFlavor,
linker_is_gnu_json: bool,
/// Objects to link before and after all other object code.
pub pre_link_objects: CrtObjects,
@@ -1300,7 +1396,7 @@ pub struct TargetOptions {
/// Optional link script applied to `dylib` and `executable` crate types.
/// This is a string containing the script, not a path. Can only be applied
/// to linkers where `linker_is_gnu` is true.
/// to linkers where linker flavor matches `LinkerFlavor::Gnu(..)`.
pub link_script: Option<StaticCow<str>>,
/// Environment variables to be set for the linker invocation.
pub link_env: StaticCow<[(StaticCow<str>, StaticCow<str>)]>,
@@ -1575,22 +1671,38 @@ pub struct TargetOptions {
/// Add arguments for the given flavor and also for its "twin" flavors
/// that have a compatible command line interface.
fn add_link_args(link_args: &mut LinkArgs, flavor: LinkerFlavor, args: &[&'static str]) {
let mut insert = |flavor| {
link_args.entry(flavor).or_default().extend(args.iter().copied().map(Cow::Borrowed))
};
fn add_link_args_iter(
link_args: &mut LinkArgs,
flavor: LinkerFlavor,
args: impl Iterator<Item = StaticCow<str>> + Clone,
) {
let mut insert = |flavor| link_args.entry(flavor).or_default().extend(args.clone());
insert(flavor);
match flavor {
LinkerFlavor::Ld => insert(LinkerFlavor::Lld(LldFlavor::Ld)),
LinkerFlavor::Msvc => insert(LinkerFlavor::Lld(LldFlavor::Link)),
LinkerFlavor::Lld(LldFlavor::Ld64) | LinkerFlavor::Lld(LldFlavor::Wasm) => {}
LinkerFlavor::Lld(lld_flavor) => {
panic!("add_link_args: use non-LLD flavor for {:?}", lld_flavor)
LinkerFlavor::Gnu(cc, lld) => {
assert_eq!(lld, Lld::No);
insert(LinkerFlavor::Gnu(cc, Lld::Yes));
}
LinkerFlavor::Gcc | LinkerFlavor::EmCc | LinkerFlavor::Bpf | LinkerFlavor::Ptx => {}
LinkerFlavor::Darwin(cc, lld) => {
assert_eq!(lld, Lld::No);
insert(LinkerFlavor::Darwin(cc, Lld::Yes));
}
LinkerFlavor::Msvc(lld) => {
assert_eq!(lld, Lld::No);
insert(LinkerFlavor::Msvc(Lld::Yes));
}
LinkerFlavor::WasmLld(..)
| LinkerFlavor::Unix(..)
| LinkerFlavor::EmCc
| LinkerFlavor::Bpf
| LinkerFlavor::Ptx => {}
}
}
fn add_link_args(link_args: &mut LinkArgs, flavor: LinkerFlavor, args: &[&'static str]) {
add_link_args_iter(link_args, flavor, args.iter().copied().map(Cow::Borrowed))
}
impl TargetOptions {
fn link_args(flavor: LinkerFlavor, args: &[&'static str]) -> LinkArgs {
let mut link_args = LinkArgs::new();
@@ -1607,7 +1719,11 @@ impl TargetOptions {
}
fn update_from_cli(&mut self) {
self.linker_flavor = LinkerFlavor::from_cli(self.linker_flavor_json);
self.linker_flavor = LinkerFlavor::from_cli_impl(
self.linker_flavor_json,
self.lld_flavor_json,
self.linker_is_gnu_json,
);
for (args, args_json) in [
(&mut self.pre_link_args, &self.pre_link_args_json),
(&mut self.late_link_args, &self.late_link_args_json),
@@ -1615,15 +1731,28 @@ impl TargetOptions {
(&mut self.late_link_args_static, &self.late_link_args_static_json),
(&mut self.post_link_args, &self.post_link_args_json),
] {
*args = args_json
.iter()
.map(|(flavor, args)| (LinkerFlavor::from_cli(*flavor), args.clone()))
.collect();
args.clear();
for (flavor, args_json) in args_json {
// Cannot use `from_cli` due to borrow checker.
let linker_flavor = LinkerFlavor::from_cli_impl(
*flavor,
self.lld_flavor_json,
self.linker_is_gnu_json,
);
match linker_flavor {
LinkerFlavor::Gnu(_, Lld::Yes)
| LinkerFlavor::Darwin(_, Lld::Yes)
| LinkerFlavor::Msvc(Lld::Yes) => {}
_ => add_link_args_iter(args, linker_flavor, args_json.iter().cloned()),
}
}
}
}
fn update_to_cli(&mut self) {
self.linker_flavor_json = self.linker_flavor.to_cli();
self.lld_flavor_json = self.linker_flavor.lld_flavor();
self.linker_is_gnu_json = self.linker_flavor.is_gnu();
for (args, args_json) in [
(&self.pre_link_args, &mut self.pre_link_args_json),
(&self.late_link_args, &mut self.late_link_args_json),
@@ -1650,10 +1779,10 @@ impl Default for TargetOptions {
abi: "".into(),
vendor: "unknown".into(),
linker: option_env!("CFG_DEFAULT_LINKER").map(|s| s.into()),
linker_flavor: LinkerFlavor::Gcc,
linker_flavor: LinkerFlavor::Gnu(Cc::Yes, Lld::No),
linker_flavor_json: LinkerFlavorCli::Gcc,
lld_flavor: LldFlavor::Ld,
linker_is_gnu: true,
lld_flavor_json: LldFlavor::Ld,
linker_is_gnu_json: true,
link_script: None,
asm_args: cvs![],
cpu: "generic".into(),
@@ -1922,6 +2051,12 @@ impl Target {
base.$key_name = s;
}
} );
($key_name:ident = $json_name:expr, bool) => ( {
let name = $json_name;
if let Some(s) = obj.remove(name).and_then(|b| b.as_bool()) {
base.$key_name = s;
}
} );
($key_name:ident, u64) => ( {
let name = (stringify!($key_name)).replace("_", "-");
if let Some(s) = obj.remove(&name).and_then(|j| Json::as_u64(&j)) {
@@ -2093,9 +2228,9 @@ impl Target {
.map(|s| s.to_string().into());
}
} );
($key_name:ident, LldFlavor) => ( {
let name = (stringify!($key_name)).replace("_", "-");
obj.remove(&name).and_then(|o| o.as_str().and_then(|s| {
($key_name:ident = $json_name:expr, LldFlavor) => ( {
let name = $json_name;
obj.remove(name).and_then(|o| o.as_str().and_then(|s| {
if let Some(flavor) = LldFlavor::from_str(&s) {
base.$key_name = flavor;
} else {
@@ -2289,8 +2424,8 @@ impl Target {
key!(vendor);
key!(linker, optional);
key!(linker_flavor_json = "linker-flavor", LinkerFlavor)?;
key!(lld_flavor, LldFlavor)?;
key!(linker_is_gnu, bool);
key!(lld_flavor_json = "lld-flavor", LldFlavor)?;
key!(linker_is_gnu_json = "linker-is-gnu", bool);
key!(pre_link_objects = "pre-link-objects", link_objects);
key!(post_link_objects = "post-link-objects", link_objects);
key!(pre_link_objects_self_contained = "pre-link-objects-fallback", link_objects);
@@ -2539,8 +2674,8 @@ impl ToJson for Target {
target_option_val!(vendor);
target_option_val!(linker);
target_option_val!(linker_flavor_json, "linker-flavor");
target_option_val!(lld_flavor);
target_option_val!(linker_is_gnu);
target_option_val!(lld_flavor_json, "lld-flavor");
target_option_val!(linker_is_gnu_json, "linker-is-gnu");
target_option_val!(pre_link_objects);
target_option_val!(post_link_objects);
target_option_val!(pre_link_objects_self_contained, "pre-link-objects-fallback");