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Rollup merge of #132934 - Zalathar:native-libs, r=jieyouxu
Overhaul the `-l` option parser (for linking to native libs) The current parser for `-l` options has accumulated over time, making it hard to follow. This PR tries to clean it up in several ways. Key changes: - This code now gets its own submodule, to slightly reduce clutter in `rustc_session::config`. - Cleaner division between iterating over multiple `-l` options, and processing each individual one. - Separate “split” step that breaks up the value string into `[KIND[:MODIFIERS]=]NAME[:NEW_NAME]`, but leaves parsing/validating those parts to later steps. - This step also gets its own (disposable) unit test, to make sure it works as expected. - A context struct reduces the burden of parameter passing, and makes it easier to write error messages that adapt to nightly/stable compilers. - Fewer calls to `nightly_options` helper functions, because at this point we can get the same information from `UnstableOptions` and `UnstableFeatures` (which are downstream of earlier calls to those helper functions). There should be no overall change in compiler behaviour.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,192 @@ | ||
| //! Parser for the `-l` command-line option, which links the generated crate to | ||
| //! a native library. | ||
| //! | ||
| //! (There is also a similar but separate syntax for `#[link]` attributes, | ||
| //! which have their own parser in `rustc_metadata`.) | ||
| use rustc_feature::UnstableFeatures; | ||
|
|
||
| use crate::EarlyDiagCtxt; | ||
| use crate::config::UnstableOptions; | ||
| use crate::utils::{NativeLib, NativeLibKind}; | ||
|
|
||
| #[cfg(test)] | ||
| mod tests; | ||
|
|
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| /// Parses all `-l` options. | ||
| pub(crate) fn parse_native_libs( | ||
| early_dcx: &EarlyDiagCtxt, | ||
| unstable_opts: &UnstableOptions, | ||
| unstable_features: UnstableFeatures, | ||
| matches: &getopts::Matches, | ||
| ) -> Vec<NativeLib> { | ||
| let cx = ParseNativeLibCx { | ||
| early_dcx, | ||
| unstable_options_enabled: unstable_opts.unstable_options, | ||
| is_nightly: unstable_features.is_nightly_build(), | ||
| }; | ||
| matches.opt_strs("l").into_iter().map(|value| parse_native_lib(&cx, &value)).collect() | ||
| } | ||
|
|
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| struct ParseNativeLibCx<'a> { | ||
| early_dcx: &'a EarlyDiagCtxt, | ||
| unstable_options_enabled: bool, | ||
| is_nightly: bool, | ||
| } | ||
|
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| impl ParseNativeLibCx<'_> { | ||
| /// If unstable values are not permitted, exits with a fatal error made by | ||
| /// combining the given strings. | ||
| fn on_unstable_value(&self, message: &str, if_nightly: &str, if_stable: &str) { | ||
| if self.unstable_options_enabled { | ||
| return; | ||
| } | ||
|
|
||
| let suffix = if self.is_nightly { if_nightly } else { if_stable }; | ||
| self.early_dcx.early_fatal(format!("{message}{suffix}")); | ||
| } | ||
| } | ||
|
|
||
| /// Parses the value of a single `-l` option. | ||
| fn parse_native_lib(cx: &ParseNativeLibCx<'_>, value: &str) -> NativeLib { | ||
| let NativeLibParts { kind, modifiers, name, new_name } = split_native_lib_value(value); | ||
|
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||
| let kind = kind.map_or(NativeLibKind::Unspecified, |kind| match kind { | ||
| "static" => NativeLibKind::Static { bundle: None, whole_archive: None }, | ||
| "dylib" => NativeLibKind::Dylib { as_needed: None }, | ||
| "framework" => NativeLibKind::Framework { as_needed: None }, | ||
| "link-arg" => { | ||
| cx.on_unstable_value( | ||
| "library kind `link-arg` is unstable", | ||
| ", the `-Z unstable-options` flag must also be passed to use it", | ||
| " and only accepted on the nightly compiler", | ||
| ); | ||
| NativeLibKind::LinkArg | ||
| } | ||
| _ => cx.early_dcx.early_fatal(format!( | ||
| "unknown library kind `{kind}`, expected one of: static, dylib, framework, link-arg" | ||
| )), | ||
| }); | ||
|
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| // Provisionally create the result, so that modifiers can modify it. | ||
| let mut native_lib = NativeLib { | ||
| name: name.to_owned(), | ||
| new_name: new_name.map(str::to_owned), | ||
| kind, | ||
| verbatim: None, | ||
| }; | ||
|
|
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| if let Some(modifiers) = modifiers { | ||
| // If multiple modifiers are present, they are separated by commas. | ||
| for modifier in modifiers.split(',') { | ||
| parse_and_apply_modifier(cx, modifier, &mut native_lib); | ||
| } | ||
| } | ||
|
|
||
| if native_lib.name.is_empty() { | ||
| cx.early_dcx.early_fatal("library name must not be empty"); | ||
| } | ||
|
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| native_lib | ||
| } | ||
|
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| /// Parses one of the comma-separated modifiers (prefixed by `+` or `-`), and | ||
| /// modifies `native_lib` appropriately. | ||
| /// | ||
| /// Exits with a fatal error if a malformed/unknown/inappropriate modifier is | ||
| /// found. | ||
| fn parse_and_apply_modifier(cx: &ParseNativeLibCx<'_>, modifier: &str, native_lib: &mut NativeLib) { | ||
| let early_dcx = cx.early_dcx; | ||
|
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| // Split off the leading `+` or `-` into a boolean value. | ||
| let (modifier, value) = match modifier.split_at_checked(1) { | ||
| Some(("+", m)) => (m, true), | ||
| Some(("-", m)) => (m, false), | ||
| _ => cx.early_dcx.early_fatal( | ||
| "invalid linking modifier syntax, expected '+' or '-' prefix \ | ||
| before one of: bundle, verbatim, whole-archive, as-needed", | ||
| ), | ||
| }; | ||
|
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| // Assigns the value (from `+` or `-`) to an empty `Option<bool>`, or emits | ||
| // a fatal error if the option has already been set. | ||
| let assign_modifier = |opt_bool: &mut Option<bool>| { | ||
| if opt_bool.is_some() { | ||
| let msg = format!("multiple `{modifier}` modifiers in a single `-l` option"); | ||
| early_dcx.early_fatal(msg) | ||
| } | ||
| *opt_bool = Some(value); | ||
| }; | ||
|
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||
| // Check that the modifier is applicable to the native lib kind, and apply it. | ||
| match (modifier, &mut native_lib.kind) { | ||
| ("bundle", NativeLibKind::Static { bundle, .. }) => assign_modifier(bundle), | ||
| ("bundle", _) => early_dcx | ||
| .early_fatal("linking modifier `bundle` is only compatible with `static` linking kind"), | ||
|
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| ("verbatim", _) => assign_modifier(&mut native_lib.verbatim), | ||
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| ("whole-archive", NativeLibKind::Static { whole_archive, .. }) => { | ||
| assign_modifier(whole_archive) | ||
| } | ||
| ("whole-archive", _) => early_dcx.early_fatal( | ||
| "linking modifier `whole-archive` is only compatible with `static` linking kind", | ||
| ), | ||
|
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| ("as-needed", NativeLibKind::Dylib { as_needed }) | ||
| | ("as-needed", NativeLibKind::Framework { as_needed }) => { | ||
| cx.on_unstable_value( | ||
| "linking modifier `as-needed` is unstable", | ||
| ", the `-Z unstable-options` flag must also be passed to use it", | ||
| " and only accepted on the nightly compiler", | ||
| ); | ||
| assign_modifier(as_needed) | ||
| } | ||
| ("as-needed", _) => early_dcx.early_fatal( | ||
| "linking modifier `as-needed` is only compatible with \ | ||
| `dylib` and `framework` linking kinds", | ||
| ), | ||
|
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||
| _ => early_dcx.early_fatal(format!( | ||
| "unknown linking modifier `{modifier}`, expected one \ | ||
| of: bundle, verbatim, whole-archive, as-needed" | ||
| )), | ||
| } | ||
| } | ||
|
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||
| #[derive(Debug, PartialEq, Eq)] | ||
| struct NativeLibParts<'a> { | ||
| kind: Option<&'a str>, | ||
| modifiers: Option<&'a str>, | ||
| name: &'a str, | ||
| new_name: Option<&'a str>, | ||
| } | ||
|
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| /// Splits a string of the form `[KIND[:MODIFIERS]=]NAME[:NEW_NAME]` into those | ||
| /// individual parts. This cannot fail, but the resulting strings require | ||
| /// further validation. | ||
| fn split_native_lib_value(value: &str) -> NativeLibParts<'_> { | ||
| // Split the initial value into `[KIND=]NAME`. | ||
| let name = value; | ||
| let (kind, name) = match name.split_once('=') { | ||
| Some((prefix, name)) => (Some(prefix), name), | ||
| None => (None, name), | ||
| }; | ||
|
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||
| // Split the kind part, if present, into `KIND[:MODIFIERS]`. | ||
| let (kind, modifiers) = match kind { | ||
| Some(kind) => match kind.split_once(':') { | ||
| Some((kind, modifiers)) => (Some(kind), Some(modifiers)), | ||
| None => (Some(kind), None), | ||
| }, | ||
| None => (None, None), | ||
| }; | ||
|
|
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| // Split the name part into `NAME[:NEW_NAME]`. | ||
| let (name, new_name) = match name.split_once(':') { | ||
| Some((name, new_name)) => (name, Some(new_name)), | ||
| None => (name, None), | ||
| }; | ||
|
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| NativeLibParts { kind, modifiers, name, new_name } | ||
| } |
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