7 files changed, 44 insertions, 20 deletions
diff --git a/compiler/rustc_session/messages.ftl b/compiler/rustc_session/messages.ftl
index 01c371ee498..a4fbab8477b 100644
--- a/compiler/rustc_session/messages.ftl
+++ b/compiler/rustc_session/messages.ftl
@@ -113,6 +113,8 @@ session_split_lto_unit_requires_lto = `-Zsplit-lto-unit` requires `-Clto`, `-Clt
 
 session_target_requires_unwind_tables = target requires unwind tables, they cannot be disabled with `-C force-unwind-tables=no`
 
+session_target_small_data_threshold_not_supported = `-Z small-data-threshold` is not supported for target {$target_triple} and will be ignored
+
 session_target_stack_protector_not_supported = `-Z stack-protector={$stack_protector}` is not supported for target {$target_triple} and will be ignored
 
 session_unleashed_feature_help_named = skipping check for `{$gate}` feature
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index f3e3b36111c..908d50a041e 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -842,11 +842,6 @@ pub struct NextSolverConfig {
     /// This is only `true` if `coherence` is also enabled.
     pub globally: bool,
 }
-impl Default for NextSolverConfig {
-    fn default() -> Self {
-        NextSolverConfig { coherence: true, globally: false }
-    }
-}
 
 #[derive(Clone)]
 pub enum Input {
diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 15bbd4ff7bf..462e2a97c33 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -183,6 +183,12 @@ pub(crate) struct StackProtectorNotSupportedForTarget<'a> {
 }
 
 #[derive(Diagnostic)]
+#[diag(session_target_small_data_threshold_not_supported)]
+pub(crate) struct SmallDataThresholdNotSupportedForTarget<'a> {
+    pub(crate) target_triple: &'a TargetTriple,
+}
+
+#[derive(Diagnostic)]
 #[diag(session_branch_protection_requires_aarch64)]
 pub(crate) struct BranchProtectionRequiresAArch64;
 
diff --git a/compiler/rustc_session/src/filesearch.rs b/compiler/rustc_session/src/filesearch.rs
index d78f4a78de7..e72d4face3c 100644
--- a/compiler/rustc_session/src/filesearch.rs
+++ b/compiler/rustc_session/src/filesearch.rs
@@ -182,7 +182,7 @@ pub fn sysroot_candidates() -> SmallVec<[PathBuf; 2]> {
         }
     }
 
-    return sysroot_candidates;
+    sysroot_candidates
 }
 
 /// Returns the provided sysroot or calls [`get_or_default_sysroot`] if it's none.
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index a57dc80b316..e487a2501e3 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -353,7 +353,7 @@ fn build_options<O: Default>(
             None => early_dcx.early_fatal(format!("unknown {outputname} option: `{key}`")),
         }
     }
-    return op;
+    op
 }
 
 #[allow(non_upper_case_globals)]
@@ -403,7 +403,7 @@ mod desc {
     pub(crate) const parse_unpretty: &str = "`string` or `string=string`";
     pub(crate) const parse_treat_err_as_bug: &str = "either no value or a non-negative number";
     pub(crate) const parse_next_solver_config: &str =
-        "either `globally` (when used without an argument), `coherence` (default) or `no`";
+        "a comma separated list of solver configurations: `globally` (default), and `coherence`";
     pub(crate) const parse_lto: &str =
         "either a boolean (`yes`, `no`, `on`, `off`, etc), `thin`, `fat`, or omitted";
     pub(crate) const parse_linker_plugin_lto: &str =
@@ -1105,16 +1105,27 @@ mod parse {
         }
     }
 
-    pub(crate) fn parse_next_solver_config(slot: &mut NextSolverConfig, v: Option<&str>) -> bool {
+    pub(crate) fn parse_next_solver_config(
+        slot: &mut Option<NextSolverConfig>,
+        v: Option<&str>,
+    ) -> bool {
         if let Some(config) = v {
-            *slot = match config {
-                "no" => NextSolverConfig { coherence: false, globally: false },
-                "coherence" => NextSolverConfig { coherence: true, globally: false },
-                "globally" => NextSolverConfig { coherence: true, globally: true },
-                _ => return false,
-            };
+            let mut coherence = false;
+            let mut globally = true;
+            for c in config.split(',') {
+                match c {
+                    "globally" => globally = true,
+                    "coherence" => {
+                        globally = false;
+                        coherence = true;
+                    }
+                    _ => return false,
+                }
+            }
+
+            *slot = Some(NextSolverConfig { coherence: coherence || globally, globally });
         } else {
-            *slot = NextSolverConfig { coherence: true, globally: true };
+            *slot = Some(NextSolverConfig { coherence: true, globally: true });
         }
 
         true
@@ -1867,7 +1878,7 @@ options! {
         "the size at which the `large_assignments` lint starts to be emitted"),
     mutable_noalias: bool = (true, parse_bool, [TRACKED],
         "emit noalias metadata for mutable references (default: yes)"),
-    next_solver: NextSolverConfig = (NextSolverConfig::default(), parse_next_solver_config, [TRACKED],
+    next_solver: Option<NextSolverConfig> = (None, parse_next_solver_config, [TRACKED],
         "enable and configure the next generation trait solver used by rustc"),
     nll_facts: bool = (false, parse_bool, [UNTRACKED],
         "dump facts from NLL analysis into side files (default: no)"),
@@ -2014,6 +2025,8 @@ written to standard error output)"),
     simulate_remapped_rust_src_base: Option<PathBuf> = (None, parse_opt_pathbuf, [TRACKED],
         "simulate the effect of remap-debuginfo = true at bootstrapping by remapping path \
         to rust's source base directory. only meant for testing purposes"),
+    small_data_threshold: Option<usize> = (None, parse_opt_number, [TRACKED],
+        "Set the threshold for objects to be stored in a \"small data\" section"),
     span_debug: bool = (false, parse_bool, [UNTRACKED],
         "forward proc_macro::Span's `Debug` impl to `Span`"),
     /// o/w tests have closure@path
diff --git a/compiler/rustc_session/src/search_paths.rs b/compiler/rustc_session/src/search_paths.rs
index d65b1b8b3f1..b212f6afa17 100644
--- a/compiler/rustc_session/src/search_paths.rs
+++ b/compiler/rustc_session/src/search_paths.rs
@@ -96,7 +96,7 @@ impl SearchPath {
         Self::new(PathKind::All, make_target_lib_path(sysroot, triple))
     }
 
-    fn new(kind: PathKind, dir: PathBuf) -> Self {
+    pub fn new(kind: PathKind, dir: PathBuf) -> Self {
         // Get the files within the directory.
         let files = match std::fs::read_dir(&dir) {
             Ok(files) => files
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 70430d82ab5..387ae1b78c4 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -30,8 +30,8 @@ use rustc_span::source_map::{FilePathMapping, SourceMap};
 use rustc_span::{FileNameDisplayPreference, RealFileName, Span, Symbol};
 use rustc_target::asm::InlineAsmArch;
 use rustc_target::spec::{
-    CodeModel, DebuginfoKind, PanicStrategy, RelocModel, RelroLevel, SanitizerSet, SplitDebuginfo,
-    StackProtector, Target, TargetTriple, TlsModel,
+    CodeModel, DebuginfoKind, PanicStrategy, RelocModel, RelroLevel, SanitizerSet,
+    SmallDataThresholdSupport, SplitDebuginfo, StackProtector, Target, TargetTriple, TlsModel,
 };
 
 use crate::code_stats::CodeStats;
@@ -1278,6 +1278,14 @@ fn validate_commandline_args_with_session_available(sess: &Session) {
         }
     }
 
+    if sess.opts.unstable_opts.small_data_threshold.is_some() {
+        if sess.target.small_data_threshold_support() == SmallDataThresholdSupport::None {
+            sess.dcx().emit_warn(errors::SmallDataThresholdNotSupportedForTarget {
+                target_triple: &sess.opts.target_triple,
+            })
+        }
+    }
+
     if sess.opts.unstable_opts.branch_protection.is_some() && sess.target.arch != "aarch64" {
         sess.dcx().emit_err(errors::BranchProtectionRequiresAArch64);
     }