Auto merge of rust-lang#116835 - oli-obk:evaluated_static_in_metadata2, r=<try>

Various const eval cleanups

This pulls out the pure refactorings from rust-lang#116564

r? `@RalfJung`

Author: bors

compiler/rustc_const_eval/src/const_eval/error.rs

@@ -117,7 +117,7 @@ where
 /// This will use the `mk` function for creating the error which will get passed labels according to
 /// the `InterpError` and the span and a stacktrace of current execution according to
 /// `get_span_and_frames`.
-pub(super) fn report<'tcx, C, F, E>(
+pub(crate) fn report<'tcx, C, F, E>(
     tcx: TyCtxt<'tcx>,
     error: InterpError<'tcx>,
     span: Option<Span>,

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -3,8 +3,7 @@ use std::mem;
 use either::{Left, Right};
 
 use rustc_hir::def::DefKind;
-use rustc_middle::mir::interpret::{ErrorHandled, InterpErrorInfo};
-use rustc_middle::mir::pretty::write_allocation_bytes;
+use rustc_middle::mir::interpret::ErrorHandled;
 use rustc_middle::mir::{self, ConstAlloc, ConstValue};
 use rustc_middle::traits::Reveal;
 use rustc_middle::ty::layout::LayoutOf;
@@ -19,8 +18,8 @@ use crate::errors;
 use crate::errors::ConstEvalError;
 use crate::interpret::eval_nullary_intrinsic;
 use crate::interpret::{
-    intern_const_alloc_recursive, CtfeValidationMode, GlobalId, Immediate, InternKind, InterpCx,
-    InterpError, InterpResult, MPlaceTy, MemoryKind, OpTy, RefTracking, StackPopCleanup,
+    intern_const_alloc_recursive, GlobalId, Immediate, InternKind, InterpCx, InterpResult,
+    MPlaceTy, MemoryKind, OpTy, StackPopCleanup,
 };
 
 // Returns a pointer to where the result lives
@@ -285,15 +284,22 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
     let def = cid.instance.def.def_id();
     let is_static = tcx.is_static(def);
 
-    let mut ecx = InterpCx::new(
+    let ecx = InterpCx::new(
         tcx,
         tcx.def_span(def),
         key.param_env,
         // Statics (and promoteds inside statics) may access other statics, because unlike consts
         // they do not have to behave "as if" they were evaluated at runtime.
         CompileTimeInterpreter::new(CanAccessStatics::from(is_static), CheckAlignment::Error),
     );
+    eval_in_interpreter(ecx, cid, is_static)
+}
 
+pub fn eval_in_interpreter<'mir, 'tcx>(
+    mut ecx: InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>>,
+    cid: GlobalId<'tcx>,
+    is_static: bool,
+) -> ::rustc_middle::mir::interpret::EvalToAllocationRawResult<'tcx> {
     let res = ecx.load_mir(cid.instance.def, cid.promoted);
     match res.and_then(|body| eval_body_using_ecx(&mut ecx, cid, &body)) {
         Err(error) => {
@@ -306,7 +312,7 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
                 // If the current item has generics, we'd like to enrich the message with the
                 // instance and its args: to show the actual compile-time values, in addition to
                 // the expression, leading to the const eval error.
-                let instance = &key.value.instance;
+                let instance = &cid.instance;
                 if !instance.args.is_empty() {
                     let instance = with_no_trimmed_paths!(instance.to_string());
                     ("const_with_path", instance)
@@ -331,60 +337,15 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
         Ok(mplace) => {
             // Since evaluation had no errors, validate the resulting constant.
             // This is a separate `try` block to provide more targeted error reporting.
-            let validation: Result<_, InterpErrorInfo<'_>> = try {
-                let mut ref_tracking = RefTracking::new(mplace.clone());
-                let mut inner = false;
-                while let Some((mplace, path)) = ref_tracking.todo.pop() {
-                    let mode = match tcx.static_mutability(cid.instance.def_id()) {
-                        Some(_) if cid.promoted.is_some() => {
-                            // Promoteds in statics are allowed to point to statics.
-                            CtfeValidationMode::Const { inner, allow_static_ptrs: true }
-                        }
-                        Some(_) => CtfeValidationMode::Regular, // a `static`
-                        None => CtfeValidationMode::Const { inner, allow_static_ptrs: false },
-                    };
-                    ecx.const_validate_operand(&mplace.into(), path, &mut ref_tracking, mode)?;
-                    inner = true;
-                }
-            };
-            let alloc_id = mplace.ptr().provenance.unwrap();
+            let validation = ecx.const_validate_mplace(&mplace, is_static, cid.promoted.is_some());
 
-            // Validation failed, report an error.
-            if let Err(error) = validation {
-                let (error, backtrace) = error.into_parts();
-                backtrace.print_backtrace();
-
-                let ub_note = matches!(error, InterpError::UndefinedBehavior(_)).then(|| {});
-
-                let alloc = ecx.tcx.global_alloc(alloc_id).unwrap_memory().inner();
-                let mut bytes = String::new();
-                if alloc.size() != abi::Size::ZERO {
-                    bytes = "\n".into();
-                    // FIXME(translation) there might be pieces that are translatable.
-                    write_allocation_bytes(*ecx.tcx, alloc, &mut bytes, "    ").unwrap();
-                }
-                let raw_bytes = errors::RawBytesNote {
-                    size: alloc.size().bytes(),
-                    align: alloc.align.bytes(),
-                    bytes,
-                };
+            let alloc_id = mplace.ptr().provenance.unwrap();
 
-                Err(super::report(
-                    *ecx.tcx,
-                    error,
-                    None,
-                    || super::get_span_and_frames(&ecx),
-                    move |span, frames| errors::UndefinedBehavior {
-                        span,
-                        ub_note,
-                        frames,
-                        raw_bytes,
-                    },
-                ))
-            } else {
+            validation
+                // Validation failed, report an error.
+                .map_err(|error| ecx.const_report_error(error, alloc_id))
                 // Convert to raw constant
-                Ok(ConstAlloc { alloc_id, ty: mplace.layout.ty })
-            }
+                .map(|()| ConstAlloc { alloc_id, ty: mplace.layout.ty })
         }
     }
 }

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -7,7 +7,7 @@ use hir::CRATE_HIR_ID;
 use rustc_hir::{self as hir, def_id::DefId, definitions::DefPathData};
 use rustc_index::IndexVec;
 use rustc_middle::mir;
-use rustc_middle::mir::interpret::{ErrorHandled, InvalidMetaKind, ReportedErrorInfo};
+use rustc_middle::mir::interpret::{alloc_range, ErrorHandled, InvalidMetaKind, ReportedErrorInfo};
 use rustc_middle::query::TyCtxtAt;
 use rustc_middle::ty::layout::{
     self, FnAbiError, FnAbiOfHelpers, FnAbiRequest, LayoutError, LayoutOf, LayoutOfHelpers,
@@ -17,6 +17,7 @@ use rustc_middle::ty::{self, GenericArgsRef, ParamEnv, Ty, TyCtxt, TypeFoldable,
 use rustc_mir_dataflow::storage::always_storage_live_locals;
 use rustc_session::Limit;
 use rustc_span::Span;
+use rustc_target::abi::{self, Abi};
 use rustc_target::abi::{call::FnAbi, Align, HasDataLayout, Size, TargetDataLayout};
 
 use super::{
@@ -1069,23 +1070,33 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         })
     }
 
-    pub fn eval_global(
+    pub fn eval_global_scalar(
         &self,
         instance: ty::Instance<'tcx>,
-    ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::Provenance>> {
+    ) -> InterpResult<'tcx, Scalar<M::Provenance>> {
         let gid = GlobalId { instance, promoted: None };
-        // For statics we pick `ParamEnv::reveal_all`, because statics don't have generics
-        // and thus don't care about the parameter environment. While we could just use
-        // `self.param_env`, that would mean we invoke the query to evaluate the static
-        // with different parameter environments, thus causing the static to be evaluated
-        // multiple times.
-        let param_env = if self.tcx.is_static(gid.instance.def_id()) {
-            ty::ParamEnv::reveal_all()
+        let (alloc_id, alloc) = if self.tcx.is_static(gid.instance.def_id()) {
+            (
+                self.tcx.reserve_and_set_static_alloc(gid.instance.def_id()),
+                self.ctfe_query(|tcx| tcx.eval_static_initializer(gid.instance.def_id()))?,
+            )
         } else {
-            self.param_env
+            let val = self.ctfe_query(|tcx| tcx.eval_to_allocation_raw(self.param_env.and(gid)))?;
+            (val.alloc_id, self.tcx.global_alloc(val.alloc_id).unwrap_memory())
         };
-        let val = self.ctfe_query(|tcx| tcx.eval_to_allocation_raw(param_env.and(gid)))?;
-        self.raw_const_to_mplace(val)
+
+        let ty = instance.ty(self.tcx.tcx, self.param_env);
+        let layout = self.layout_of(ty)?;
+        let read_provenance = matches!(
+            layout.abi,
+            Abi::Scalar(abi::Scalar::Initialized { value: abi::Primitive::Pointer(..), .. })
+        );
+
+        let scalar = alloc
+            .inner()
+            .read_scalar(self, alloc_range(Size::ZERO, layout.size), read_provenance)
+            .map_err(|err| err.to_interp_error(alloc_id))?;
+        self.adjust_const_scalar(scalar)
     }
 
     pub fn eval_mir_constant(

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -723,19 +723,23 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         Ok(op)
     }
 
+    pub(super) fn adjust_const_scalar(
+        &self,
+        scalar: Scalar,
+    ) -> InterpResult<'tcx, Scalar<M::Provenance>> {
+        Ok(match scalar {
+            Scalar::Ptr(ptr, size) => Scalar::Ptr(self.global_base_pointer(ptr)?, size),
+            Scalar::Int(int) => Scalar::Int(int),
+        })
+    }
+
     pub(crate) fn const_val_to_op(
         &self,
         val_val: mir::ConstValue<'tcx>,
         ty: Ty<'tcx>,
         layout: Option<TyAndLayout<'tcx>>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
         // Other cases need layout.
-        let adjust_scalar = |scalar| -> InterpResult<'tcx, _> {
-            Ok(match scalar {
-                Scalar::Ptr(ptr, size) => Scalar::Ptr(self.global_base_pointer(ptr)?, size),
-                Scalar::Int(int) => Scalar::Int(int),
-            })
-        };
         let layout = from_known_layout(self.tcx, self.param_env, layout, || self.layout_of(ty))?;
         let imm = match val_val {
             mir::ConstValue::Indirect { alloc_id, offset } => {
@@ -744,7 +748,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let ptr = self.global_base_pointer(Pointer::new(alloc_id, offset))?;
                 return Ok(self.ptr_to_mplace(ptr.into(), layout).into());
             }
-            mir::ConstValue::Scalar(x) => adjust_scalar(x)?.into(),
+            mir::ConstValue::Scalar(x) => self.adjust_const_scalar(x)?.into(),
             mir::ConstValue::ZeroSized => Immediate::Uninit,
             mir::ConstValue::Slice { data, meta } => {
                 // We rely on mutability being set correctly in `data` to prevent writes

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -13,18 +13,21 @@ use rustc_ast::Mutability;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_middle::mir::interpret::{
-    ExpectedKind, InterpError, InvalidMetaKind, Misalignment, PointerKind, ValidationErrorInfo,
-    ValidationErrorKind, ValidationErrorKind::*,
+    ErrorHandled, ExpectedKind, InterpError, InterpErrorInfo, InvalidMetaKind, Misalignment,
+    PointerKind, ValidationErrorInfo, ValidationErrorKind, ValidationErrorKind::*,
 };
+use rustc_middle::mir::pretty::write_allocation_bytes;
 use rustc_middle::ty;
 use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
 use rustc_span::symbol::{sym, Symbol};
 use rustc_target::abi::{
-    Abi, FieldIdx, Scalar as ScalarAbi, Size, VariantIdx, Variants, WrappingRange,
+    self, Abi, FieldIdx, Scalar as ScalarAbi, Size, VariantIdx, Variants, WrappingRange,
 };
 
 use std::hash::Hash;
 
+use crate::errors;
+
 use super::{
     AllocId, CheckInAllocMsg, GlobalAlloc, ImmTy, Immediate, InterpCx, InterpResult, MPlaceTy,
     Machine, MemPlaceMeta, OpTy, Pointer, Projectable, Scalar, ValueVisitor,
@@ -929,7 +932,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     /// - no pointers to statics.
     /// - no `UnsafeCell` or non-ZST `&mut`.
     #[inline(always)]
-    pub fn const_validate_operand(
+    fn const_validate_operand(
         &self,
         op: &OpTy<'tcx, M::Provenance>,
         path: Vec<PathElem>,
@@ -939,6 +942,64 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         self.validate_operand_internal(op, path, Some(ref_tracking), Some(ctfe_mode))
     }
 
+    #[inline(always)]
+    pub fn const_validate_mplace(
+        &self,
+        mplace: &MPlaceTy<'tcx, M::Provenance>,
+        is_static: bool,
+        is_promoted: bool,
+    ) -> InterpResult<'tcx> {
+        let mut ref_tracking = RefTracking::new(mplace.clone());
+        let mut inner = false;
+        while let Some((mplace, path)) = ref_tracking.todo.pop() {
+            let mode = if is_static {
+                if is_promoted {
+                    // Promoteds in statics are allowed to point to statics.
+                    CtfeValidationMode::Const { inner, allow_static_ptrs: true }
+                } else {
+                    // a `static`
+                    CtfeValidationMode::Regular
+                }
+            } else {
+                CtfeValidationMode::Const { inner, allow_static_ptrs: false }
+            };
+            self.const_validate_operand(&mplace.into(), path, &mut ref_tracking, mode)?;
+            inner = true;
+        }
+
+        Ok(())
+    }
+
+    #[inline(always)]
+    pub fn const_report_error(
+        &self,
+        error: InterpErrorInfo<'tcx>,
+        alloc_id: AllocId,
+    ) -> ErrorHandled {
+        let (error, backtrace) = error.into_parts();
+        backtrace.print_backtrace();
+
+        let ub_note = matches!(error, InterpError::UndefinedBehavior(_)).then(|| {});
+
+        let alloc = self.tcx.global_alloc(alloc_id).unwrap_memory().inner();
+        let mut bytes = String::new();
+        if alloc.size() != abi::Size::ZERO {
+            bytes = "\n".into();
+            // FIXME(translation) there might be pieces that are translatable.
+            write_allocation_bytes(*self.tcx, alloc, &mut bytes, "    ").unwrap();
+        }
+        let raw_bytes =
+            errors::RawBytesNote { size: alloc.size().bytes(), align: alloc.align.bytes(), bytes };
+
+        crate::const_eval::report(
+            *self.tcx,
+            error,
+            None,
+            || crate::const_eval::get_span_and_frames(self),
+            move |span, frames| errors::UndefinedBehavior { span, ub_note, frames, raw_bytes },
+        )
+    }
+
     /// This function checks the data at `op` to be runtime-valid.
     /// `op` is assumed to cover valid memory if it is an indirect operand.
     /// It will error if the bits at the destination do not match the ones described by the layout.

src/tools/miri/src/helpers.rs

@@ -141,11 +141,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
         let this = self.eval_context_ref();
         let instance = this.resolve_path(path, Namespace::ValueNS);
         // We don't give a span -- this isn't actually used directly by the program anyway.
-        let const_val = this.eval_global(instance).unwrap_or_else(|err| {
+        this.eval_global_scalar(instance).unwrap_or_else(|err| {
             panic!("failed to evaluate required Rust item: {path:?}\n{err:?}")
-        });
-        this.read_scalar(&const_val)
-            .unwrap_or_else(|err| panic!("failed to read required Rust item: {path:?}\n{err:?}"))
+        })
     }
 
     /// Helper function to get a `libc` constant as a `Scalar`.