Rollup merge of rust-lang#138641 - jieyouxu:print-supported-crate-types, r=Urgau

Add unstable `--print=supported-crate-types` option

MCP: rust-lang/compiler-team#836
Tracking issue: rust-lang#138640

### Test coverage

Two tests:

1. `tests/ui/print-request/stability.rs` to check that `--print=supported-crate-types` is `-Zunstable-options`-gated
2. `tests/ui/print-request/supported-crate-types.rs` is added as a basic smoke test. Observe that the compiler stdout corresponds to the below *Example output* section (e.g. `proc-macro` is unsupported on `wasm32-unknown-unknown` currently).

### Example output

<details>
<summary>For `x86_64-unknown-linux-gnu`</summary>

Notice the presence of `{c,}dylib` and `proc-macro`:
```
bin
cdylib
dylib
lib
proc-macro
rlib
staticlib
```
</details>

<details>
<summary>For `wasm32-unknown-unknown`</summary>

Notice the absence of `dylib` and `proc-macro`:
```
bin
cdylib
lib
rlib
staticlib
```
</details>

<details>
<summary>For `x86_64-unknown-linux-musl`</summary>

Notice the absence of `{c,}dylib` but presence of `proc-macro`:
```
bin
lib
proc-macro
rlib
staticlib
```
</details>

### Documentation

I added an entry in the unstable book's print request section to document this `supported-crate-types` print request.

### Unresolved questions

- [ ] (Name bikeshedding) is `supported-crate-types` a good name for the print request? I'm inclined to say it's good enough for an unstable print request, but may be worth revisiting at stabilization time.

### Stability

This print request being added is *unstable* in this PR. A separate stabilization PR following the usual compiler flag stabilization procedure should be filed for stabilization after some baking time.

### Review remarks

Best reviewed commit-by-commit.

r? compiler

Author: compiler-errors

compiler/rustc_driver_impl/src/lib.rs

@@ -20,7 +20,7 @@
 // tidy-alphabetical-end
 
 use std::cmp::max;
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, BTreeSet};
 use std::ffi::OsString;
 use std::fmt::Write as _;
 use std::fs::{self, File};
@@ -61,7 +61,7 @@ use rustc_session::config::{
 };
 use rustc_session::getopts::{self, Matches};
 use rustc_session::lint::{Lint, LintId};
-use rustc_session::output::collect_crate_types;
+use rustc_session::output::{CRATE_TYPES, collect_crate_types, invalid_output_for_target};
 use rustc_session::{EarlyDiagCtxt, Session, config, filesearch};
 use rustc_span::FileName;
 use rustc_target::json::ToJson;
@@ -790,6 +790,16 @@ fn print_crate_info(
                     sess.dcx().fatal("only Apple targets currently support deployment version info")
                 }
             }
+            SupportedCrateTypes => {
+                let supported_crate_types = CRATE_TYPES
+                    .iter()
+                    .filter(|(_, crate_type)| !invalid_output_for_target(&sess, *crate_type))
+                    .map(|(crate_type_sym, _)| *crate_type_sym)
+                    .collect::<BTreeSet<_>>();
+                for supported_crate_type in supported_crate_types {
+                    println_info!("{}", supported_crate_type.as_str());
+                }
+            }
         }
 
         req.out.overwrite(&crate_info, sess);

compiler/rustc_session/src/config.rs

@@ -58,6 +58,7 @@ pub const PRINT_KINDS: &[(&str, PrintKind)] = &[
     ("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),
@@ -888,6 +889,7 @@ pub enum PrintKind {
     RelocationModels,
     SplitDebuginfo,
     StackProtectorStrategies,
+    SupportedCrateTypes,
     Sysroot,
     TargetCPUs,
     TargetFeatures,
@@ -2063,7 +2065,10 @@ fn check_print_request_stability(
     (print_name, print_kind): (&str, PrintKind),
 ) {
     match print_kind {
-        PrintKind::AllTargetSpecsJson | PrintKind::CheckCfg | PrintKind::TargetSpecJson
+        PrintKind::AllTargetSpecsJson
+        | PrintKind::CheckCfg
+        | PrintKind::SupportedCrateTypes
+        | PrintKind::TargetSpecJson
             if !unstable_opts.unstable_options =>
         {
             early_dcx.early_fatal(format!(

src/doc/unstable-book/src/compiler-flags/print-supported-crate-types.md

@@ -0,0 +1,27 @@
+# `print=supported-crate-types`
+
+The tracking issue for this feature is: [#138640](https://github.com/rust-lang/rust/issues/138640).
+
+------------------------
+
+This option of the `--print` flag produces a list of crate types (delimited by newlines) supported for the given target.
+
+The crate type strings correspond to the values accepted by the `--crate-type` flag.
+
+Intended to be used like this:
+
+```bash
+rustc --print=supported-crate-types -Zunstable-options --target=x86_64-unknown-linux-gnu
+```
+
+Example output for `x86_64-unknown-linux-gnu`:
+
+```text
+bin
+cdylib
+dylib
+lib
+proc-macro
+rlib
+staticlib
+```

tests/run-make/rustc-help/help-v.stdout

@@ -29,7 +29,7 @@ Options:
         --emit [asm|llvm-bc|llvm-ir|obj|metadata|link|dep-info|mir]
                         Comma separated list of types of output for the
                         compiler to emit
-        --print [all-target-specs-json|calling-conventions|cfg|check-cfg|code-models|crate-name|deployment-target|file-names|host-tuple|link-args|native-static-libs|relocation-models|split-debuginfo|stack-protector-strategies|sysroot|target-cpus|target-features|target-libdir|target-list|target-spec-json|tls-models]
+        --print [all-target-specs-json|calling-conventions|cfg|check-cfg|code-models|crate-name|deployment-target|file-names|host-tuple|link-args|native-static-libs|relocation-models|split-debuginfo|stack-protector-strategies|supported-crate-types|sysroot|target-cpus|target-features|target-libdir|target-list|target-spec-json|tls-models]
                         Compiler information to print on stdout
     -g                  Equivalent to -C debuginfo=2
     -O                  Equivalent to -C opt-level=3

tests/run-make/rustc-help/help.stdout

@@ -29,7 +29,7 @@ Options:
         --emit [asm|llvm-bc|llvm-ir|obj|metadata|link|dep-info|mir]
                         Comma separated list of types of output for the
                         compiler to emit
-        --print [all-target-specs-json|calling-conventions|cfg|check-cfg|code-models|crate-name|deployment-target|file-names|host-tuple|link-args|native-static-libs|relocation-models|split-debuginfo|stack-protector-strategies|sysroot|target-cpus|target-features|target-libdir|target-list|target-spec-json|tls-models]
+        --print [all-target-specs-json|calling-conventions|cfg|check-cfg|code-models|crate-name|deployment-target|file-names|host-tuple|link-args|native-static-libs|relocation-models|split-debuginfo|stack-protector-strategies|supported-crate-types|sysroot|target-cpus|target-features|target-libdir|target-list|target-spec-json|tls-models]
                         Compiler information to print on stdout
     -g                  Equivalent to -C debuginfo=2
     -O                  Equivalent to -C opt-level=3

tests/ui/invalid-compile-flags/print-without-arg.stderr

@@ -1,5 +1,5 @@
 error: Argument to option 'print' missing
        Usage:
-           --print [all-target-specs-json|calling-conventions|cfg|check-cfg|code-models|crate-name|deployment-target|file-names|host-tuple|link-args|native-static-libs|relocation-models|split-debuginfo|stack-protector-strategies|sysroot|target-cpus|target-features|target-libdir|target-list|target-spec-json|tls-models]
+           --print [all-target-specs-json|calling-conventions|cfg|check-cfg|code-models|crate-name|deployment-target|file-names|host-tuple|link-args|native-static-libs|relocation-models|split-debuginfo|stack-protector-strategies|supported-crate-types|sysroot|target-cpus|target-features|target-libdir|target-list|target-spec-json|tls-models]
                                Compiler information to print on stdout
 

tests/ui/invalid-compile-flags/print.stderr

@@ -1,5 +1,5 @@
 error: unknown print request: `yyyy`
   |
-  = help: valid print requests are: `all-target-specs-json`, `calling-conventions`, `cfg`, `check-cfg`, `code-models`, `crate-name`, `deployment-target`, `file-names`, `host-tuple`, `link-args`, `native-static-libs`, `relocation-models`, `split-debuginfo`, `stack-protector-strategies`, `sysroot`, `target-cpus`, `target-features`, `target-libdir`, `target-list`, `target-spec-json`, `tls-models`
+  = help: valid print requests are: `all-target-specs-json`, `calling-conventions`, `cfg`, `check-cfg`, `code-models`, `crate-name`, `deployment-target`, `file-names`, `host-tuple`, `link-args`, `native-static-libs`, `relocation-models`, `split-debuginfo`, `stack-protector-strategies`, `supported-crate-types`, `sysroot`, `target-cpus`, `target-features`, `target-libdir`, `target-list`, `target-spec-json`, `tls-models`
   = help: for more information, see the rustc book: https://doc.rust-lang.org/rustc/command-line-arguments.html#--print-print-compiler-information
 

tests/ui/print-request/print-lints-help.rs

@@ -0,0 +1,7 @@
+//! Check that we point to `-Whelp` to guide the user to find the list of lints if the user requests
+//! `--print=lints` (which is not a valid print request).
+
+//@ compile-flags: --print lints
+//@ error-pattern: error: unknown print request: `lints`
+//@ error-pattern: help: use `-Whelp` to print a list of lints
+//@ error-pattern: help: for more information, see the rustc book

tests/ui/rustc-print-info-issue-138612.stderr tests/ui/print-request/print-lints-help.stderr

@@ -1,6 +1,6 @@
 error: unknown print request: `lints`
   |
-  = help: valid print requests are: `all-target-specs-json`, `calling-conventions`, `cfg`, `check-cfg`, `code-models`, `crate-name`, `deployment-target`, `file-names`, `host-tuple`, `link-args`, `native-static-libs`, `relocation-models`, `split-debuginfo`, `stack-protector-strategies`, `sysroot`, `target-cpus`, `target-features`, `target-libdir`, `target-list`, `target-spec-json`, `tls-models`
+  = help: valid print requests are: `all-target-specs-json`, `calling-conventions`, `cfg`, `check-cfg`, `code-models`, `crate-name`, `deployment-target`, `file-names`, `host-tuple`, `link-args`, `native-static-libs`, `relocation-models`, `split-debuginfo`, `stack-protector-strategies`, `supported-crate-types`, `sysroot`, `target-cpus`, `target-features`, `target-libdir`, `target-list`, `target-spec-json`, `tls-models`
   = help: use `-Whelp` to print a list of lints
   = help: for more information, see the rustc book: https://doc.rust-lang.org/rustc/command-line-arguments.html#--print-print-compiler-information
 

tests/ui/print-request/stability.rs

@@ -22,6 +22,10 @@
 //@[check_cfg] compile-flags: --print=check-cfg
 //@[check_cfg] error-pattern: the `-Z unstable-options` flag must also be passed
 
+//@ revisions: supported_crate_types
+//@[supported_crate_types] compile-flags: --print=supported-crate-types
+//@[supported_crate_types] error-pattern: the `-Z unstable-options` flag must also be passed
+
 //@ revisions: target_spec_json
 //@[target_spec_json] compile-flags: --print=target-spec-json
 //@[target_spec_json] error-pattern: the `-Z unstable-options` flag must also be passed

tests/ui/print-request/supported-crate-types.linux.stdout

@@ -0,0 +1,7 @@
+bin
+cdylib
+dylib
+lib
+proc-macro
+rlib
+staticlib

tests/ui/print-request/supported-crate-types.musl.stdout

@@ -0,0 +1,5 @@
+bin
+lib
+proc-macro
+rlib
+staticlib

tests/ui/print-request/supported-crate-types.rs

@@ -0,0 +1,20 @@
+//! Basic smoke test for `--print=supported-crate-types`, which should print a newline delimited
+//! list of crate types supported by the given target. This test cherry-picks a few well-known
+//! targets as examples.
+//!
+//! Tracking issue: <https://github.com/rust-lang/rust/issues/138640>
+
+// ignore-tidy-linelength
+
+//@ check-pass
+
+//@ revisions: wasm musl linux
+
+//@[wasm] compile-flags: --target=wasm32-unknown-unknown --print=supported-crate-types -Zunstable-options
+//@[wasm] needs-llvm-components: webassembly
+
+//@[musl] compile-flags: --target=x86_64-unknown-linux-musl --print=supported-crate-types -Zunstable-options
+//@[musl] needs-llvm-components: x86
+
+//@[linux] compile-flags: --target=x86_64-unknown-linux-gnu --print=supported-crate-types -Zunstable-options
+//@[linux] needs-llvm-components: x86

tests/ui/print-request/supported-crate-types.wasm.stdout

@@ -0,0 +1,5 @@
+bin
+cdylib
+lib
+rlib
+staticlib