Unrolled build for #148990

Rollup merge of #148990 - Zalathar:print-kind, r=WaffleLapkin

Exhaustively specify names and stability of `--print` values

While trying to add a new unstable `--print` kind for use by compiletest, I found that the relevant code is quite awkward to work with, for a few reasons:

- It's spread across various parts of a multi-thousand-line source file.
- All newly-added `PrintKind` values are automatically treated as *stable*, unless they are explicitly marked as unstable in a helper function far away.
- Parsing `--print` values relies on a separate table of name/value mappings, but there's no exhaustiveness check for that table.

This PR therefore:
- Extracts the relevant code into its own `print_request` submodule.
- Uses a macro-rules derive to obtain an exhaustive list of values.
- Uses exhaustive matches to associate a name and stability status with each `PrintKind` value.

---

The first commit moves code to a separate module; the second commit contains actual changes.

There should be no change to compiler output.

Author: rust-timer

compiler/rustc_session/src/config.rs

@@ -36,6 +36,7 @@ use tracing::debug;
 
 pub use crate::config::cfg::{Cfg, CheckCfg, ExpectedValues};
 use crate::config::native_libs::parse_native_libs;
+pub use crate::config::print_request::{PrintKind, PrintRequest};
 use crate::errors::FileWriteFail;
 pub use crate::options::*;
 use crate::search_paths::SearchPath;
@@ -45,37 +46,9 @@ use crate::{EarlyDiagCtxt, HashStableContext, Session, filesearch, lint};
 mod cfg;
 mod externs;
 mod native_libs;
+mod print_request;
 pub mod sigpipe;
 
-pub const PRINT_KINDS: &[(&str, PrintKind)] = &[
-    // tidy-alphabetical-start
-    ("all-target-specs-json", PrintKind::AllTargetSpecsJson),
-    ("calling-conventions", PrintKind::CallingConventions),
-    ("cfg", PrintKind::Cfg),
-    ("check-cfg", PrintKind::CheckCfg),
-    ("code-models", PrintKind::CodeModels),
-    ("crate-name", PrintKind::CrateName),
-    ("crate-root-lint-levels", PrintKind::CrateRootLintLevels),
-    ("deployment-target", PrintKind::DeploymentTarget),
-    ("file-names", PrintKind::FileNames),
-    ("host-tuple", PrintKind::HostTuple),
-    ("link-args", PrintKind::LinkArgs),
-    ("native-static-libs", PrintKind::NativeStaticLibs),
-    ("relocation-models", PrintKind::RelocationModels),
-    ("split-debuginfo", PrintKind::SplitDebuginfo),
-    ("stack-protector-strategies", PrintKind::StackProtectorStrategies),
-    ("supported-crate-types", PrintKind::SupportedCrateTypes),
-    ("sysroot", PrintKind::Sysroot),
-    ("target-cpus", PrintKind::TargetCPUs),
-    ("target-features", PrintKind::TargetFeatures),
-    ("target-libdir", PrintKind::TargetLibdir),
-    ("target-list", PrintKind::TargetList),
-    ("target-spec-json", PrintKind::TargetSpecJson),
-    ("target-spec-json-schema", PrintKind::TargetSpecJsonSchema),
-    ("tls-models", PrintKind::TlsModels),
-    // tidy-alphabetical-end
-];
-
 /// The different settings that the `-C strip` flag can have.
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum Strip {
@@ -1015,42 +988,6 @@ impl ExternEntry {
     }
 }
 
-#[derive(Clone, PartialEq, Debug)]
-pub struct PrintRequest {
-    pub kind: PrintKind,
-    pub out: OutFileName,
-}
-
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
-pub enum PrintKind {
-    // tidy-alphabetical-start
-    AllTargetSpecsJson,
-    CallingConventions,
-    Cfg,
-    CheckCfg,
-    CodeModels,
-    CrateName,
-    CrateRootLintLevels,
-    DeploymentTarget,
-    FileNames,
-    HostTuple,
-    LinkArgs,
-    NativeStaticLibs,
-    RelocationModels,
-    SplitDebuginfo,
-    StackProtectorStrategies,
-    SupportedCrateTypes,
-    Sysroot,
-    TargetCPUs,
-    TargetFeatures,
-    TargetLibdir,
-    TargetList,
-    TargetSpecJson,
-    TargetSpecJsonSchema,
-    TlsModels,
-    // tidy-alphabetical-end
-}
-
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq, Default)]
 pub struct NextSolverConfig {
     /// Whether the new trait solver should be enabled in coherence.
@@ -1798,14 +1735,6 @@ The default is {DEFAULT_EDITION} and the latest stable edition is {LATEST_STABLE
     )
 });
 
-static PRINT_HELP: LazyLock<String> = LazyLock::new(|| {
-    format!(
-        "Compiler information to print on stdout (or to a file)\n\
-        INFO may be one of <{}>.",
-        PRINT_KINDS.iter().map(|(name, _)| format!("{name}")).collect::<Vec<_>>().join("|")
-    )
-});
-
 static EMIT_HELP: LazyLock<String> = LazyLock::new(|| {
     let mut result =
         String::from("Comma separated list of types of output for the compiler to emit.\n");
@@ -1872,7 +1801,7 @@ pub fn rustc_optgroups() -> Vec<RustcOptGroup> {
         opt(Stable, Opt, "", "crate-name", "Specify the name of the crate being built", "<NAME>"),
         opt(Stable, Opt, "", "edition", &EDITION_STRING, EDITION_NAME_LIST),
         opt(Stable, Multi, "", "emit", &EMIT_HELP, "<TYPE>[=<FILE>]"),
-        opt(Stable, Multi, "", "print", &PRINT_HELP, "<INFO>[=<FILE>]"),
+        opt(Stable, Multi, "", "print", &print_request::PRINT_HELP, "<INFO>[=<FILE>]"),
         opt(Stable, FlagMulti, "g", "", "Equivalent to -C debuginfo=2", ""),
         opt(Stable, FlagMulti, "O", "", "Equivalent to -C opt-level=3", ""),
         opt(Stable, Opt, "o", "", "Write output to FILENAME", "<FILENAME>"),
@@ -2320,108 +2249,6 @@ fn should_override_cgus_and_disable_thinlto(
     (disable_local_thinlto, codegen_units)
 }
 
-fn collect_print_requests(
-    early_dcx: &EarlyDiagCtxt,
-    cg: &mut CodegenOptions,
-    unstable_opts: &UnstableOptions,
-    matches: &getopts::Matches,
-) -> Vec<PrintRequest> {
-    let mut prints = Vec::<PrintRequest>::new();
-    if cg.target_cpu.as_deref() == Some("help") {
-        prints.push(PrintRequest { kind: PrintKind::TargetCPUs, out: OutFileName::Stdout });
-        cg.target_cpu = None;
-    };
-    if cg.target_feature == "help" {
-        prints.push(PrintRequest { kind: PrintKind::TargetFeatures, out: OutFileName::Stdout });
-        cg.target_feature = String::new();
-    }
-
-    // We disallow reusing the same path in multiple prints, such as `--print
-    // cfg=output.txt --print link-args=output.txt`, because outputs are printed
-    // by disparate pieces of the compiler, and keeping track of which files
-    // need to be overwritten vs appended to is annoying.
-    let mut printed_paths = FxHashSet::default();
-
-    prints.extend(matches.opt_strs("print").into_iter().map(|req| {
-        let (req, out) = split_out_file_name(&req);
-
-        let kind = if let Some((print_name, print_kind)) =
-            PRINT_KINDS.iter().find(|&&(name, _)| name == req)
-        {
-            check_print_request_stability(early_dcx, unstable_opts, (print_name, *print_kind));
-            *print_kind
-        } else {
-            let is_nightly = nightly_options::match_is_nightly_build(matches);
-            emit_unknown_print_request_help(early_dcx, req, is_nightly)
-        };
-
-        let out = out.unwrap_or(OutFileName::Stdout);
-        if let OutFileName::Real(path) = &out {
-            if !printed_paths.insert(path.clone()) {
-                early_dcx.early_fatal(format!(
-                    "cannot print multiple outputs to the same path: {}",
-                    path.display(),
-                ));
-            }
-        }
-
-        PrintRequest { kind, out }
-    }));
-
-    prints
-}
-
-fn check_print_request_stability(
-    early_dcx: &EarlyDiagCtxt,
-    unstable_opts: &UnstableOptions,
-    (print_name, print_kind): (&str, PrintKind),
-) {
-    if !is_print_request_stable(print_kind) && !unstable_opts.unstable_options {
-        early_dcx.early_fatal(format!(
-            "the `-Z unstable-options` flag must also be passed to enable the `{print_name}` \
-                print option"
-        ));
-    }
-}
-
-fn is_print_request_stable(print_kind: PrintKind) -> bool {
-    match print_kind {
-        PrintKind::AllTargetSpecsJson
-        | PrintKind::CheckCfg
-        | PrintKind::CrateRootLintLevels
-        | PrintKind::SupportedCrateTypes
-        | PrintKind::TargetSpecJson
-        | PrintKind::TargetSpecJsonSchema => false,
-        _ => true,
-    }
-}
-
-fn emit_unknown_print_request_help(early_dcx: &EarlyDiagCtxt, req: &str, is_nightly: bool) -> ! {
-    let prints = PRINT_KINDS
-        .iter()
-        .filter_map(|(name, kind)| {
-            // If we're not on nightly, we don't want to print unstable options
-            if !is_nightly && !is_print_request_stable(*kind) {
-                None
-            } else {
-                Some(format!("`{name}`"))
-            }
-        })
-        .collect::<Vec<_>>();
-    let prints = prints.join(", ");
-
-    let mut diag = early_dcx.early_struct_fatal(format!("unknown print request: `{req}`"));
-    #[allow(rustc::diagnostic_outside_of_impl)]
-    diag.help(format!("valid print requests are: {prints}"));
-
-    if req == "lints" {
-        diag.help(format!("use `-Whelp` to print a list of lints"));
-    }
-
-    diag.help(format!("for more information, see the rustc book: https://doc.rust-lang.org/rustc/command-line-arguments.html#--print-print-compiler-information"));
-    diag.emit()
-}
-
 pub fn parse_target_triple(early_dcx: &EarlyDiagCtxt, matches: &getopts::Matches) -> TargetTuple {
     match matches.opt_str("target") {
         Some(target) if target.ends_with(".json") => {
@@ -2846,7 +2673,7 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
         ));
     }
 
-    let prints = collect_print_requests(early_dcx, &mut cg, &unstable_opts, matches);
+    let prints = print_request::collect_print_requests(early_dcx, &mut cg, &unstable_opts, matches);
 
     // -Zretpoline-external-thunk also requires -Zretpoline
     if unstable_opts.retpoline_external_thunk {