inline_threshold mark deprecated

Author: klensy

compiler/rustc_driver_impl/src/lib.rs

@@ -1128,10 +1128,6 @@ pub fn describe_flag_categories(early_dcx: &EarlyDiagCtxt, matches: &Matches) ->
         early_dcx.early_warn("the `-Cno-stack-check` flag is deprecated and does nothing");
     }
 
-    if cg_flags.iter().any(|x| x.starts_with("inline-threshold")) {
-        early_dcx.early_warn("the `-Cinline-threshold` flag is deprecated and does nothing (consider using `-Cllvm-args=--inline-threshold=...`)");
-    }
-
     if cg_flags.iter().any(|x| *x == "passes=list") {
         let backend_name = debug_flags.iter().find_map(|x| x.strip_prefix("codegen-backend="));
 

compiler/rustc_session/src/options.rs

@@ -336,7 +336,12 @@ fn build_options<O: Default>(
 
         let option_to_lookup = key.replace('-', "_");
         match descrs.iter().find(|(name, ..)| *name == option_to_lookup) {
-            Some((_, setter, type_desc, _, _)) => {
+            Some((_, setter, type_desc, opt_desc, deprecated_do_nothing)) => {
+                if *deprecated_do_nothing {
+                    // deprecation works for prefixed options only
+                    assert!(!prefix.is_empty());
+                    early_dcx.early_warn(format!("`-{prefix} {key}`: {opt_desc}"));
+                }
                 if !setter(&mut op, value) {
                     match value {
                         None => early_dcx.early_fatal(
@@ -1582,7 +1587,8 @@ options! {
     #[rustc_lint_opt_deny_field_access("documented to do nothing")]
     inline_threshold: Option<u32> = (None, parse_opt_number, [TRACKED],
         "this option is deprecated and does nothing \
-        (consider using `-Cllvm-args=--inline-threshold=...`)"),
+        (consider using `-Cllvm-args=--inline-threshold=...`)",
+        deprecated_do_nothing: true),
     #[rustc_lint_opt_deny_field_access("use `Session::instrument_coverage` instead of this field")]
     instrument_coverage: InstrumentCoverage = (InstrumentCoverage::No, parse_instrument_coverage, [TRACKED],
         "instrument the generated code to support LLVM source-based code coverage reports \

tests/ui/deprecation/deprecated_inline_threshold.stderr

@@ -1,2 +1,2 @@
-warning: the `-Cinline-threshold` flag is deprecated and does nothing (consider using `-Cllvm-args=--inline-threshold=...`)
+warning: `-C inline-threshold`: this option is deprecated and does nothing (consider using `-Cllvm-args=--inline-threshold=...`)
 

tests/ui/deprecation/deprecated_inline_threshold_bad_val.rs

@@ -0,0 +1,5 @@
+//@ check-fail
+//@ compile-flags: -Cinline-threshold=asd
+// Tests that deprecated option with wrong value still emit deprecation warning.
+
+fn main() {}

tests/ui/deprecation/deprecated_inline_threshold_bad_val.stderr

@@ -0,0 +1,4 @@
+warning: `-C inline-threshold`: this option is deprecated and does nothing (consider using `-Cllvm-args=--inline-threshold=...`)
+
+error: incorrect value `asd` for codegen option `inline-threshold` - a number was expected
+

tests/ui/deprecation/deprecated_inline_threshold_no_val.rs

@@ -0,0 +1,5 @@
+//@ check-fail
+//@ compile-flags: -Cinline-threshold
+// Tests that deprecated option with wrong(empty) value still emit deprecation warning.
+
+fn main() {}

tests/ui/deprecation/deprecated_inline_threshold_no_val.stderr

@@ -0,0 +1,4 @@
+warning: `-C inline-threshold`: this option is deprecated and does nothing (consider using `-Cllvm-args=--inline-threshold=...`)
+
+error: codegen option `inline-threshold` requires a number (C inline-threshold=<value>)
+