Auto merge of #69833 - Centril:rollup-mh74yue, r=Centril

Rollup of 7 pull requests

Successful merges:

 - #69120 (Don't give invalid suggestion on desugared span.)
 - #69326 (mir-interpret: add method to read wide strings from Memory)
 - #69608 (Expose target libdir information via print command)
 - #69734 (Change DIBuilderCreateEnumerator signature to match LLVM 9)
 - #69800 (Compile address sanitizer test with debuginfo)
 - #69807 (Cleanup E0391 explanation)
 - #69820 (clean up E0392 explanation)

Failed merges:

r? @ghost

15 files changed, 152 insertions, 72 deletions

diff --git a/src/doc/rustc/src/command-line-arguments.md b/src/doc/rustc/src/command-line-arguments.md
index 659f8f65e65..7a7838d965b 100644
--- a/src/doc/rustc/src/command-line-arguments.md
+++ b/src/doc/rustc/src/command-line-arguments.md
@@ -146,6 +146,7 @@ The valid types of print values are:
 - `crate-name` — The name of the crate.
 - `file-names` — The names of the files created by the `link` emit kind.
 - `sysroot` — Path to the sysroot.
+- `target-libdir` - Path to the target libdir.
 - `cfg` — List of cfg values. See [conditional compilation] for more
   information about cfg values.
 - `target-list` — List of known targets. The target may be selected with the
diff --git a/src/librustc/mir/interpret/value.rs b/src/librustc/mir/interpret/value.rs
index 2be60d35af3..9dc0b24cd2f 100644
--- a/src/librustc/mir/interpret/value.rs
+++ b/src/librustc/mir/interpret/value.rs
@@ -613,6 +613,11 @@ impl<'tcx, Tag> ScalarMaybeUndef<Tag> {
     }
 
     #[inline(always)]
+    pub fn to_u16(self) -> InterpResult<'tcx, u16> {
+        self.not_undef()?.to_u16()
+    }
+
+    #[inline(always)]
     pub fn to_u32(self) -> InterpResult<'tcx, u32> {
         self.not_undef()?.to_u32()
     }
@@ -633,6 +638,11 @@ impl<'tcx, Tag> ScalarMaybeUndef<Tag> {
     }
 
     #[inline(always)]
+    pub fn to_i16(self) -> InterpResult<'tcx, i16> {
+        self.not_undef()?.to_i16()
+    }
+
+    #[inline(always)]
     pub fn to_i32(self) -> InterpResult<'tcx, i32> {
         self.not_undef()?.to_i32()
     }
diff --git a/src/librustc_codegen_llvm/debuginfo/metadata.rs b/src/librustc_codegen_llvm/debuginfo/metadata.rs
index 9e52598f2e0..19bd0b6f7e6 100644
--- a/src/librustc_codegen_llvm/debuginfo/metadata.rs
+++ b/src/librustc_codegen_llvm/debuginfo/metadata.rs
@@ -1779,13 +1779,20 @@ fn prepare_enum_metadata(
                 .discriminants(cx.tcx)
                 .zip(&def.variants)
                 .map(|((_, discr), v)| {
-                    let name = SmallCStr::new(&v.ident.as_str());
+                    let name = v.ident.as_str();
+                    let is_unsigned = match discr.ty.kind {
+                        ty::Int(_) => false,
+                        ty::Uint(_) => true,
+                        _ => bug!("non integer discriminant"),
+                    };
                     unsafe {
                         Some(llvm::LLVMRustDIBuilderCreateEnumerator(
                             DIB(cx),
-                            name.as_ptr(),
+                            name.as_ptr().cast(),
+                            name.len(),
                             // FIXME: what if enumeration has i128 discriminant?
-                            discr.val as u64,
+                            discr.val as i64,
+                            is_unsigned,
                         ))
                     }
                 })
@@ -1794,13 +1801,15 @@ fn prepare_enum_metadata(
                 .as_generator()
                 .variant_range(enum_def_id, cx.tcx)
                 .map(|variant_index| {
-                    let name = SmallCStr::new(&substs.as_generator().variant_name(variant_index));
+                    let name = substs.as_generator().variant_name(variant_index);
                     unsafe {
                         Some(llvm::LLVMRustDIBuilderCreateEnumerator(
                             DIB(cx),
-                            name.as_ptr(),
-                            // FIXME: what if enumeration has i128 discriminant?
-                            variant_index.as_usize() as u64,
+                            name.as_ptr().cast(),
+                            name.len(),
+                            // Generators use u32 as discriminant type.
+                            variant_index.as_u32().into(),
+                            true, // IsUnsigned
                         ))
                     }
                 })
diff --git a/src/librustc_codegen_llvm/llvm/ffi.rs b/src/librustc_codegen_llvm/llvm/ffi.rs
index f56647044e0..8b796e0423b 100644
--- a/src/librustc_codegen_llvm/llvm/ffi.rs
+++ b/src/librustc_codegen_llvm/llvm/ffi.rs
@@ -1776,7 +1776,9 @@ extern "C" {
     pub fn LLVMRustDIBuilderCreateEnumerator(
         Builder: &DIBuilder<'a>,
         Name: *const c_char,
-        Val: u64,
+        NameLen: size_t,
+        Value: i64,
+        IsUnsigned: bool,
     ) -> &'a DIEnumerator;
 
     pub fn LLVMRustDIBuilderCreateEnumerationType(
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 789507fb48b..e6c98ad27e8 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -680,6 +680,10 @@ impl RustcDefaultCalls {
                     println!("{}", targets.join("\n"));
                 }
                 Sysroot => println!("{}", sess.sysroot.display()),
+                TargetLibdir => println!(
+                    "{}",
+                    sess.target_tlib_path.as_ref().unwrap_or(&sess.host_tlib_path).dir.display()
+                ),
                 TargetSpec => println!("{}", sess.target.target.to_json().pretty()),
                 FileNames | CrateName => {
                     let input = input.unwrap_or_else(|| {
diff --git a/src/librustc_error_codes/error_codes/E0391.md b/src/librustc_error_codes/error_codes/E0391.md
index 5db9ad16d08..dff50ccaa0b 100644
--- a/src/librustc_error_codes/error_codes/E0391.md
+++ b/src/librustc_error_codes/error_codes/E0391.md
@@ -1,7 +1,6 @@
-This error indicates that some types or traits depend on each other
-and therefore cannot be constructed.
+A type dependency cycle has been encountered.
 
-The following example contains a circular dependency between two traits:
+Erroneous code example:
 
 ```compile_fail,E0391
 trait FirstTrait : SecondTrait {
@@ -12,3 +11,6 @@ trait SecondTrait : FirstTrait {
 
 }
 ```
+
+The previous example contains a circular dependency between two traits:
+`FirstTrait` depends on `SecondTrait` which itself depends on `FirstTrait`.
diff --git a/src/librustc_error_codes/error_codes/E0392.md b/src/librustc_error_codes/error_codes/E0392.md
index 1d93e904e37..f373d89456d 100644
--- a/src/librustc_error_codes/error_codes/E0392.md
+++ b/src/librustc_error_codes/error_codes/E0392.md
@@ -1,5 +1,6 @@
-This error indicates that a type or lifetime parameter has been declared
-but not actually used. Here is an example that demonstrates the error:
+A type or lifetime parameter has been declared but is not actually used.
+
+Erroneous code example:
 
 ```compile_fail,E0392
 enum Foo<T> {
diff --git a/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs b/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
index 5c37faaa82a..76475e70958 100644
--- a/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
+++ b/src/librustc_mir/borrow_check/diagnostics/mutability_errors.rs
@@ -329,40 +329,6 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 if self.body.local_decls[local].is_user_variable() =>
             {
                 let local_decl = &self.body.local_decls[local];
-                let suggestion = match local_decl.local_info {
-                    LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::ImplicitSelf(_))) => {
-                        Some(suggest_ampmut_self(self.infcx.tcx, local_decl))
-                    }
-
-                    LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
-                        mir::VarBindingForm {
-                            binding_mode: ty::BindingMode::BindByValue(_),
-                            opt_ty_info,
-                            ..
-                        },
-                    ))) => Some(suggest_ampmut(
-                        self.infcx.tcx,
-                        self.body,
-                        local,
-                        local_decl,
-                        opt_ty_info,
-                    )),
-
-                    LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
-                        mir::VarBindingForm {
-                            binding_mode: ty::BindingMode::BindByReference(_),
-                            ..
-                        },
-                    ))) => {
-                        let pattern_span = local_decl.source_info.span;
-                        suggest_ref_mut(self.infcx.tcx, pattern_span)
-                            .map(|replacement| (pattern_span, replacement))
-                    }
-
-                    LocalInfo::User(ClearCrossCrate::Clear) => bug!("saw cleared local state"),
-
-                    _ => unreachable!(),
-                };
 
                 let (pointer_sigil, pointer_desc) = if local_decl.ty.is_region_ptr() {
                     ("&", "reference")
@@ -370,17 +336,53 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     ("*const", "pointer")
                 };
 
-                if let Some((err_help_span, suggested_code)) = suggestion {
-                    err.span_suggestion(
-                        err_help_span,
-                        &format!("consider changing this to be a mutable {}", pointer_desc),
-                        suggested_code,
-                        Applicability::MachineApplicable,
-                    );
-                }
-
                 match self.local_names[local] {
                     Some(name) if !local_decl.from_compiler_desugaring() => {
+                        let suggestion = match local_decl.local_info {
+                            LocalInfo::User(ClearCrossCrate::Set(
+                                mir::BindingForm::ImplicitSelf(_),
+                            )) => Some(suggest_ampmut_self(self.infcx.tcx, local_decl)),
+
+                            LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
+                                mir::VarBindingForm {
+                                    binding_mode: ty::BindingMode::BindByValue(_),
+                                    opt_ty_info,
+                                    ..
+                                },
+                            ))) => Some(suggest_ampmut(
+                                self.infcx.tcx,
+                                self.body,
+                                local,
+                                local_decl,
+                                opt_ty_info,
+                            )),
+
+                            LocalInfo::User(ClearCrossCrate::Set(mir::BindingForm::Var(
+                                mir::VarBindingForm {
+                                    binding_mode: ty::BindingMode::BindByReference(_),
+                                    ..
+                                },
+                            ))) => {
+                                let pattern_span = local_decl.source_info.span;
+                                suggest_ref_mut(self.infcx.tcx, pattern_span)
+                                    .map(|replacement| (pattern_span, replacement))
+                            }
+
+                            LocalInfo::User(ClearCrossCrate::Clear) => {
+                                bug!("saw cleared local state")
+                            }
+
+                            _ => unreachable!(),
+                        };
+
+                        if let Some((err_help_span, suggested_code)) = suggestion {
+                            err.span_suggestion(
+                                err_help_span,
+                                &format!("consider changing this to be a mutable {}", pointer_desc),
+                                suggested_code,
+                                Applicability::MachineApplicable,
+                            );
+                        }
                         err.span_label(
                             span,
                             format!(
diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 3c4a1857f96..82a467c7ba9 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -798,6 +798,33 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
         self.get_raw(ptr.alloc_id)?.read_c_str(self, ptr)
     }
 
+    /// Reads a 0x0000-terminated u16-sequence from memory. Returns them as a Vec<u16>.
+    /// Terminator 0x0000 is not included in the returned Vec<u16>.
+    ///
+    /// Performs appropriate bounds checks.
+    pub fn read_wide_str(&self, ptr: Scalar<M::PointerTag>) -> InterpResult<'tcx, Vec<u16>> {
+        let size_2bytes = Size::from_bytes(2);
+        let align_2bytes = Align::from_bytes(2).unwrap();
+        // We need to read at least 2 bytes, so we *need* a ptr.
+        let mut ptr = self.force_ptr(ptr)?;
+        let allocation = self.get_raw(ptr.alloc_id)?;
+        let mut u16_seq = Vec::new();
+
+        loop {
+            ptr = self
+                .check_ptr_access(ptr.into(), size_2bytes, align_2bytes)?
+                .expect("cannot be a ZST");
+            let single_u16 = allocation.read_scalar(self, ptr, size_2bytes)?.to_u16()?;
+            if single_u16 != 0x0000 {
+                u16_seq.push(single_u16);
+                ptr = ptr.offset(size_2bytes, self)?;
+            } else {
+                break;
+            }
+        }
+        Ok(u16_seq)
+    }
+
     /// Writes the given stream of bytes into memory.
     ///
     /// Performs appropriate bounds checks.
diff --git a/src/librustc_session/config.rs b/src/librustc_session/config.rs
index db4412a18a3..c273e7fdbf9 100644
--- a/src/librustc_session/config.rs
+++ b/src/librustc_session/config.rs
@@ -391,6 +391,7 @@ impl ExternEntry {
 pub enum PrintRequest {
     FileNames,
     Sysroot,
+    TargetLibdir,
     CrateName,
     Cfg,
     TargetList,
@@ -912,7 +913,7 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
             "",
             "print",
             "Compiler information to print on stdout",
-            "[crate-name|file-names|sysroot|cfg|target-list|\
+            "[crate-name|file-names|sysroot|target-libdir|cfg|target-list|\
              target-cpus|target-features|relocation-models|\
              code-models|tls-models|target-spec-json|native-static-libs]",
         ),
@@ -1344,6 +1345,7 @@ fn collect_print_requests(
         "crate-name" => PrintRequest::CrateName,
         "file-names" => PrintRequest::FileNames,
         "sysroot" => PrintRequest::Sysroot,
+        "target-libdir" => PrintRequest::TargetLibdir,
         "cfg" => PrintRequest::Cfg,
         "target-list" => PrintRequest::TargetList,
         "target-cpus" => PrintRequest::TargetCPUs,
diff --git a/src/rustllvm/RustWrapper.cpp b/src/rustllvm/RustWrapper.cpp
index 49b6e1bfec3..0e430d3881e 100644
--- a/src/rustllvm/RustWrapper.cpp
+++ b/src/rustllvm/RustWrapper.cpp
@@ -891,10 +891,10 @@ extern "C" LLVMValueRef LLVMRustDIBuilderInsertDeclareAtEnd(
       unwrap(InsertAtEnd)));
 }
 
-extern "C" LLVMMetadataRef
-LLVMRustDIBuilderCreateEnumerator(LLVMRustDIBuilderRef Builder,
-                                  const char *Name, uint64_t Val) {
-  return wrap(Builder->createEnumerator(Name, Val));
+extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateEnumerator(
+    LLVMRustDIBuilderRef Builder, const char *Name, size_t NameLen,
+    int64_t Value, bool IsUnsigned) {
+  return wrap(Builder->createEnumerator({Name, NameLen}, Value, IsUnsigned));
 }
 
 extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateEnumerationType(
diff --git a/src/test/codegen/enum-discriminant-value.rs b/src/test/codegen/enum-discriminant-value.rs
new file mode 100644
index 00000000000..f9da987765f
--- /dev/null
+++ b/src/test/codegen/enum-discriminant-value.rs
@@ -0,0 +1,27 @@
+// Verify that DIEnumerator uses isUnsigned flag when appropriate.
+//
+// compile-flags: -g -C no-prepopulate-passes
+
+#[repr(i64)]
+pub enum I64 {
+    I64Min = std::i64::MIN,
+    I64Max = std::i64::MAX,
+}
+
+#[repr(u64)]
+pub enum U64 {
+    U64Min = std::u64::MIN,
+    U64Max = std::u64::MAX,
+}
+
+fn main() {
+    let _a = I64::I64Min;
+    let _b = I64::I64Max;
+    let _c = U64::U64Min;
+    let _d = U64::U64Max;
+}
+
+// CHECK: !DIEnumerator(name: "I64Min", value: -9223372036854775808)
+// CHECK: !DIEnumerator(name: "I64Max", value: 9223372036854775807)
+// CHECK: !DIEnumerator(name: "U64Min", value: 0, isUnsigned: true)
+// CHECK: !DIEnumerator(name: "U64Max", value: 18446744073709551615, isUnsigned: true)
diff --git a/src/test/ui/async-await/dont-print-desugared-async.stderr b/src/test/ui/async-await/dont-print-desugared-async.stderr
index 2bf1e77f09b..d80467c7fa8 100644
--- a/src/test/ui/async-await/dont-print-desugared-async.stderr
+++ b/src/test/ui/async-await/dont-print-desugared-async.stderr
@@ -2,10 +2,7 @@ error[E0596]: cannot borrow data in a `&` reference as mutable
   --> $DIR/dont-print-desugared-async.rs:5:20
    |
 LL | async fn async_fn(&ref mut s: &[i32]) {}
-   |                   -^^^^^^^^^
-   |                   ||
-   |                   |cannot borrow as mutable through `&` reference
-   |                   help: consider changing this to be a mutable reference: `&mut ref mut s`
+   |                    ^^^^^^^^^ cannot borrow as mutable through `&` reference
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/nll/dont-print-desugared.stderr b/src/test/ui/nll/dont-print-desugared.stderr
index 45d7cbcdfbe..88773def8b7 100644
--- a/src/test/ui/nll/dont-print-desugared.stderr
+++ b/src/test/ui/nll/dont-print-desugared.stderr
@@ -2,10 +2,7 @@ error[E0596]: cannot borrow data in a `&` reference as mutable
   --> $DIR/dont-print-desugared.rs:4:10
    |
 LL |     for &ref mut x in s {}
-   |         -^^^^^^^^^
-   |         ||
-   |         |cannot borrow as mutable through `&` reference
-   |         help: consider changing this to be a mutable reference: `&mut ref mut x`
+   |          ^^^^^^^^^ cannot borrow as mutable through `&` reference
 
 error[E0597]: `y` does not live long enough
   --> $DIR/dont-print-desugared.rs:17:16
diff --git a/src/test/ui/sanitize/address.rs b/src/test/ui/sanitize/address.rs
index d27a30a2dc5..f8650cd86d5 100644
--- a/src/test/ui/sanitize/address.rs
+++ b/src/test/ui/sanitize/address.rs
@@ -1,16 +1,15 @@
 // needs-sanitizer-support
 // only-x86_64
 //
-// compile-flags: -Z sanitizer=address -O
+// compile-flags: -Z sanitizer=address -O -g
 //
 // run-fail
 // error-pattern: AddressSanitizer: stack-buffer-overflow
-// error-pattern: 'xs' <== Memory access at offset
+// error-pattern: 'xs' (line 15) <== Memory access at offset
 
 #![feature(test)]
 
 use std::hint::black_box;
-use std::mem;
 
 fn main() {
     let xs = [0, 1, 2, 3];