Auto merge of rust-lang#122303 - matthiaskrgr:rollup-ieokhnz, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#121754 ([bootstrap] Move the `split-debuginfo` setting to the per-target section)
 - rust-lang#122205 (ensure that sysroot is properly set for cross-targets)
 - rust-lang#122275 (disable OOM test in Miri)
 - rust-lang#122276 (io::Read trait: make it more clear when we are adressing implementations vs callers)
 - rust-lang#122286 (use Instance::expect_resolve() instead of unwraping Instance::resolve())
 - rust-lang#122290 (MIR printing: print the path of uneval'd const)
 - rust-lang#122293 (diagnostics: Do not suggest using `#[unix_sigpipe]` without a value)
 - rust-lang#122297 (bootstrap: document what the triples in 'Build' mean)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_codegen_cranelift/src/main_shim.rs

@@ -115,14 +115,12 @@ pub(crate) fn maybe_create_entry_wrapper(
                         termination_trait,
                     )
                     .unwrap();
-                let report = Instance::resolve(
+                let report = Instance::expect_resolve(
                     tcx,
                     ParamEnv::reveal_all(),
                     report.def_id,
                     tcx.mk_args(&[GenericArg::from(main_ret_ty)]),
                 )
-                .unwrap()
-                .unwrap()
                 .polymorphize(tcx);
 
                 let report_name = tcx.symbol_name(report).name;
@@ -142,14 +140,12 @@ pub(crate) fn maybe_create_entry_wrapper(
                 }
             } else if is_main_fn {
                 let start_def_id = tcx.require_lang_item(LangItem::Start, None);
-                let start_instance = Instance::resolve(
+                let start_instance = Instance::expect_resolve(
                     tcx,
                     ParamEnv::reveal_all(),
                     start_def_id,
                     tcx.mk_args(&[main_ret_ty.into()]),
                 )
-                .unwrap()
-                .unwrap()
                 .polymorphize(tcx);
                 let start_func_id = import_function(tcx, m, start_instance);
 

compiler/rustc_codegen_gcc/src/context.rs

@@ -473,14 +473,12 @@ impl<'gcc, 'tcx> MiscMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         let tcx = self.tcx;
         let func = match tcx.lang_items().eh_personality() {
             Some(def_id) if !wants_msvc_seh(self.sess()) => {
-                let instance = ty::Instance::resolve(
+                let instance = ty::Instance::expect_resolve(
                     tcx,
                     ty::ParamEnv::reveal_all(),
                     def_id,
                     ty::List::empty(),
-                )
-                .unwrap()
-                .unwrap();
+                );
 
                 let symbol_name = tcx.symbol_name(instance).name;
                 let fn_abi = self.fn_abi_of_instance(instance, ty::List::empty());

compiler/rustc_codegen_llvm/src/context.rs

@@ -558,11 +558,12 @@ impl<'ll, 'tcx> MiscMethods<'tcx> for CodegenCx<'ll, 'tcx> {
 
         let tcx = self.tcx;
         let llfn = match tcx.lang_items().eh_personality() {
-            Some(def_id) if name.is_none() => self.get_fn_addr(
-                ty::Instance::resolve(tcx, ty::ParamEnv::reveal_all(), def_id, ty::List::empty())
-                    .unwrap()
-                    .unwrap(),
-            ),
+            Some(def_id) if name.is_none() => self.get_fn_addr(ty::Instance::expect_resolve(
+                tcx,
+                ty::ParamEnv::reveal_all(),
+                def_id,
+                ty::List::empty(),
+            )),
             _ => {
                 let name = name.unwrap_or("rust_eh_personality");
                 if let Some(llfn) = self.get_declared_value(name) {

compiler/rustc_codegen_ssa/src/base.rs

@@ -467,16 +467,12 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
         let (start_fn, start_ty, args) = if let EntryFnType::Main { sigpipe } = entry_type {
             let start_def_id = cx.tcx().require_lang_item(LangItem::Start, None);
-            let start_fn = cx.get_fn_addr(
-                ty::Instance::resolve(
-                    cx.tcx(),
-                    ty::ParamEnv::reveal_all(),
-                    start_def_id,
-                    cx.tcx().mk_args(&[main_ret_ty.into()]),
-                )
-                .unwrap()
-                .unwrap(),
-            );
+            let start_fn = cx.get_fn_addr(ty::Instance::expect_resolve(
+                cx.tcx(),
+                ty::ParamEnv::reveal_all(),
+                start_def_id,
+                cx.tcx().mk_args(&[main_ret_ty.into()]),
+            ));
 
             let i8_ty = cx.type_i8();
             let arg_sigpipe = bx.const_u8(sigpipe);

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -67,7 +67,7 @@ fn eval_body_using_ecx<'mir, 'tcx>(
     trace!(
         "eval_body_using_ecx: pushing stack frame for global: {}{}",
         with_no_trimmed_paths!(ecx.tcx.def_path_str(cid.instance.def_id())),
-        cid.promoted.map_or_else(String::new, |p| format!("::promoted[{p:?}]"))
+        cid.promoted.map_or_else(String::new, |p| format!("::{p:?}"))
     );
 
     ecx.push_stack_frame(

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -243,14 +243,12 @@ impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> {
         } else if Some(def_id) == self.tcx.lang_items().panic_fmt() {
             // For panic_fmt, call const_panic_fmt instead.
             let const_def_id = self.tcx.require_lang_item(LangItem::ConstPanicFmt, None);
-            let new_instance = ty::Instance::resolve(
+            let new_instance = ty::Instance::expect_resolve(
                 *self.tcx,
                 ty::ParamEnv::reveal_all(),
                 const_def_id,
                 instance.args,
-            )
-            .unwrap()
-            .unwrap();
+            );
 
             return Ok(Some(new_instance));
         } else if Some(def_id) == self.tcx.lang_items().align_offset_fn() {

compiler/rustc_feature/src/builtin_attrs.rs

@@ -389,7 +389,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
 
     // Entry point:
-    gated!(unix_sigpipe, Normal, template!(Word, NameValueStr: "inherit|sig_ign|sig_dfl"), ErrorFollowing, experimental!(unix_sigpipe)),
+    gated!(unix_sigpipe, Normal, template!(NameValueStr: "inherit|sig_ign|sig_dfl"), ErrorFollowing, experimental!(unix_sigpipe)),
     ungated!(start, Normal, template!(Word), WarnFollowing, @only_local: true),
     ungated!(no_start, CrateLevel, template!(Word), WarnFollowing, @only_local: true),
     ungated!(no_main, CrateLevel, template!(Word), WarnFollowing, @only_local: true),

compiler/rustc_middle/src/mir/consts.rs

@@ -7,6 +7,7 @@ use rustc_target::abi::{HasDataLayout, Size};
 
 use crate::mir::interpret::{alloc_range, AllocId, ConstAllocation, ErrorHandled, Scalar};
 use crate::mir::{pretty_print_const_value, Promoted};
+use crate::ty::print::with_no_trimmed_paths;
 use crate::ty::GenericArgsRef;
 use crate::ty::ScalarInt;
 use crate::ty::{self, print::pretty_print_const, Ty, TyCtxt};
@@ -489,9 +490,18 @@ impl<'tcx> Display for Const<'tcx> {
             Const::Ty(c) => pretty_print_const(c, fmt, true),
             Const::Val(val, ty) => pretty_print_const_value(val, ty, fmt),
             // FIXME(valtrees): Correctly print mir constants.
-            Const::Unevaluated(..) => {
-                fmt.write_str("_")?;
-                Ok(())
+            Const::Unevaluated(c, _ty) => {
+                ty::tls::with(move |tcx| {
+                    let c = tcx.lift(c).unwrap();
+                    // Matches `GlobalId` printing.
+                    let instance =
+                        with_no_trimmed_paths!(tcx.def_path_str_with_args(c.def, c.args));
+                    write!(fmt, "{instance}")?;
+                    if let Some(promoted) = c.promoted {
+                        write!(fmt, "::{promoted:?}")?;
+                    }
+                    Ok(())
+                })
             }
         }
     }

compiler/rustc_middle/src/mir/pretty.rs

@@ -496,7 +496,7 @@ fn write_mir_sig(tcx: TyCtxt<'_>, body: &Body<'_>, w: &mut dyn io::Write) -> io:
         _ => tcx.is_closure_like(def_id),
     };
     match (kind, body.source.promoted) {
-        (_, Some(i)) => write!(w, "{i:?} in ")?,
+        (_, Some(_)) => write!(w, "const ")?, // promoteds are the closest to consts
         (DefKind::Const | DefKind::AssocConst, _) => write!(w, "const ")?,
         (DefKind::Static(hir::Mutability::Not), _) => write!(w, "static ")?,
         (DefKind::Static(hir::Mutability::Mut), _) => write!(w, "static mut ")?,
@@ -509,6 +509,9 @@ fn write_mir_sig(tcx: TyCtxt<'_>, body: &Body<'_>, w: &mut dyn io::Write) -> io:
         // see notes on #41697 elsewhere
         write!(w, "{}", tcx.def_path_str(def_id))?
     }
+    if let Some(p) = body.source.promoted {
+        write!(w, "::{p:?}")?;
+    }
 
     if body.source.promoted.is_none() && is_function {
         write!(w, "(")?;

compiler/rustc_monomorphize/src/collector.rs

@@ -1339,14 +1339,12 @@ impl<'v> RootCollector<'_, 'v> {
             main_ret_ty.no_bound_vars().unwrap(),
         );
 
-        let start_instance = Instance::resolve(
+        let start_instance = Instance::expect_resolve(
             self.tcx,
             ty::ParamEnv::reveal_all(),
             start_def_id,
             self.tcx.mk_args(&[main_ret_ty.into()]),
-        )
-        .unwrap()
-        .unwrap();
+        );
 
         self.output.push(create_fn_mono_item(self.tcx, start_instance, DUMMY_SP));
     }

compiler/rustc_passes/src/entry.rs

@@ -156,13 +156,13 @@ fn sigpipe(tcx: TyCtxt<'_>, def_id: DefId) -> u8 {
             (Some(sym::inherit), None) => sigpipe::INHERIT,
             (Some(sym::sig_ign), None) => sigpipe::SIG_IGN,
             (Some(sym::sig_dfl), None) => sigpipe::SIG_DFL,
-            (_, Some(_)) => {
-                // Keep going so that `fn emit_malformed_attribute()` can print
-                // an excellent error message
+            (Some(_), None) => {
+                tcx.dcx().emit_err(UnixSigpipeValues { span: attr.span });
                 sigpipe::DEFAULT
             }
             _ => {
-                tcx.dcx().emit_err(UnixSigpipeValues { span: attr.span });
+                // Keep going so that `fn emit_malformed_attribute()` can print
+                // an excellent error message
                 sigpipe::DEFAULT
             }
         }

config.example.toml

@@ -543,23 +543,15 @@
 # FIXME(#61117): Some tests fail when this option is enabled.
 #debuginfo-level-tests = 0
 
-# Should rustc be build with split debuginfo? Default is platform dependent.
-# Valid values are the same as those accepted by `-C split-debuginfo`
-# (`off`/`unpacked`/`packed`).
+# Should rustc and the standard library be built with split debuginfo? Default
+# is platform dependent.
 #
-# On Linux, split debuginfo is disabled by default.
+# This field is deprecated, use `target.<triple>.split-debuginfo` instead.
 #
-# On Apple platforms, unpacked split debuginfo is used by default. Unpacked
-# debuginfo does not run `dsymutil`, which packages debuginfo from disparate
-# object files into a single `.dSYM` file. `dsymutil` adds time to builds for
-# no clear benefit, and also makes it more difficult for debuggers to find
-# debug info. The compiler currently defaults to running `dsymutil` to preserve
-# its historical default, but when compiling the compiler itself, we skip it by
-# default since we know it's safe to do so in that case.
+# The value specified here is only used when targeting the `build.build` triple,
+# and is overridden by `target.<triple>.split-debuginfo` if specified.
 #
-# On Windows platforms, packed debuginfo is the only supported option,
-# producing a `.pdb` file.
-#split-debuginfo = if linux { off } else if windows { packed } else if apple { unpacked }
+#split-debuginfo = see target.<triple>.split-debuginfo
 
 # Whether or not `panic!`s generate backtraces (RUST_BACKTRACE)
 #backtrace = true
@@ -769,6 +761,26 @@
 # Setting this will override the `use-lld` option for Rust code when targeting MSVC.
 #linker = "cc" (path)
 
+# Should rustc and the standard library be built with split debuginfo? Default
+# is platform dependent.
+#
+# Valid values are the same as those accepted by `-C split-debuginfo`
+# (`off`/`unpacked`/`packed`).
+#
+# On Linux, split debuginfo is disabled by default.
+#
+# On Apple platforms, unpacked split debuginfo is used by default. Unpacked
+# debuginfo does not run `dsymutil`, which packages debuginfo from disparate
+# object files into a single `.dSYM` file. `dsymutil` adds time to builds for
+# no clear benefit, and also makes it more difficult for debuggers to find
+# debug info. The compiler currently defaults to running `dsymutil` to preserve
+# its historical default, but when compiling the compiler itself, we skip it by
+# default since we know it's safe to do so in that case.
+#
+# On Windows platforms, packed debuginfo is the only supported option,
+# producing a `.pdb` file.
+#split-debuginfo = if linux { off } else if windows { packed } else if apple { unpacked }
+
 # Path to the `llvm-config` binary of the installation of a custom LLVM to link
 # against. Note that if this is specified we don't compile LLVM at all for this
 # target.

library/std/src/io/mod.rs

@@ -692,10 +692,9 @@ pub trait Read {
     /// Callers have to ensure that no unchecked out-of-bounds accesses are possible even if
     /// `n > buf.len()`.
     ///
-    /// No guarantees are provided about the contents of `buf` when this
-    /// function is called, so implementations cannot rely on any property of the
-    /// contents of `buf` being true. It is recommended that *implementations*
-    /// only write data to `buf` instead of reading its contents.
+    /// *Implementations* of this method can make no assumptions about the contents of `buf` when
+    /// this function is called. It is recommended that implementations only write data to `buf`
+    /// instead of reading its contents.
     ///
     /// Correspondingly, however, *callers* of this method in unsafe code must not assume
     /// any guarantees about how the implementation uses `buf`. The trait is safe to implement,
@@ -901,12 +900,10 @@ pub trait Read {
     /// This function reads as many bytes as necessary to completely fill the
     /// specified buffer `buf`.
     ///
-    /// No guarantees are provided about the contents of `buf` when this
-    /// function is called, so implementations cannot rely on any property of the
-    /// contents of `buf` being true. It is recommended that implementations
-    /// only write data to `buf` instead of reading its contents. The
-    /// documentation on [`read`] has a more detailed explanation on this
-    /// subject.
+    /// *Implementations* of this method can make no assumptions about the contents of `buf` when
+    /// this function is called. It is recommended that implementations only write data to `buf`
+    /// instead of reading its contents. The documentation on [`read`] has a more detailed
+    /// explanation of this subject.
     ///
     /// # Errors
     ///

library/std/src/io/tests.rs

@@ -694,6 +694,8 @@ fn read_buf_full_read() {
 }
 
 #[test]
+// Miri does not support signalling OOM
+#[cfg_attr(miri, ignore)]
 // 64-bit only to be sure the allocator will fail fast on an impossible to satsify size
 #[cfg(target_pointer_width = "64")]
 fn try_oom_error() {

src/bootstrap/src/core/build_steps/test.rs

@@ -2580,6 +2580,12 @@ impl Step for Crate {
         // we're working with automatically.
         let compiler = builder.compiler_for(compiler.stage, compiler.host, target);
 
+        // During cross compilations, sysroot for the target may not be available.
+        // Ensure that it is prepared.
+        if builder.config.build != target {
+            builder.ensure(compile::Rustc::new(compiler, target));
+        }
+
         let mut cargo = builder::Cargo::new(
             builder,
             compiler,

src/bootstrap/src/core/builder.rs

@@ -1730,15 +1730,16 @@ impl<'a> Builder<'a> {
             },
         );
 
+        let split_debuginfo = self.config.split_debuginfo(target);
         let split_debuginfo_is_stable = target.contains("linux")
             || target.contains("apple")
-            || (target.is_msvc() && self.config.rust_split_debuginfo == SplitDebuginfo::Packed)
-            || (target.is_windows() && self.config.rust_split_debuginfo == SplitDebuginfo::Off);
+            || (target.is_msvc() && split_debuginfo == SplitDebuginfo::Packed)
+            || (target.is_windows() && split_debuginfo == SplitDebuginfo::Off);
 
         if !split_debuginfo_is_stable {
             rustflags.arg("-Zunstable-options");
         }
-        match self.config.rust_split_debuginfo {
+        match split_debuginfo {
             SplitDebuginfo::Packed => rustflags.arg("-Csplit-debuginfo=packed"),
             SplitDebuginfo::Unpacked => rustflags.arg("-Csplit-debuginfo=unpacked"),
             SplitDebuginfo::Off => rustflags.arg("-Csplit-debuginfo=off"),