Always use consteval to codegen caller_location.

Author: anp

src/librustc/query/mod.rs

@@ -466,6 +466,12 @@ rustc_queries! {
             no_force
             desc { "extract field of const" }
         }
+
+        query const_caller_location(key: (syntax_pos::Symbol, u32, u32)) -> &'tcx ty::Const<'tcx> {
+            eval_always
+            no_force
+            desc { "get a &core::panic::Location referring to a span" }
+        }
     }
 
     TypeChecking {

src/librustc/ty/query/keys.rs

@@ -208,3 +208,13 @@ impl<'tcx, T> Key for Canonical<'tcx, T> {
         DUMMY_SP
     }
 }
+
+impl Key for (Symbol, u32, u32) {
+    fn query_crate(&self) -> CrateNum {
+        LOCAL_CRATE
+    }
+
+    fn default_span(&self, _tcx: TyCtxt<'_>) -> Span {
+        DUMMY_SP
+    }
+}

src/librustc_codegen_llvm/builder.rs

@@ -2,7 +2,6 @@ use crate::llvm::{AtomicRmwBinOp, AtomicOrdering, SynchronizationScope};
 use crate::llvm::{self, False, BasicBlock};
 use crate::common::Funclet;
 use crate::context::CodegenCx;
-use crate::syntax_pos::Pos;
 use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
@@ -24,7 +23,6 @@ use std::ffi::CStr;
 use std::ops::{Deref, Range};
 use std::ptr;
 use std::iter::TrustedLen;
-use syntax::symbol::Symbol;
 
 // All Builders must have an llfn associated with them
 #[must_use]
@@ -1068,20 +1066,6 @@ impl StaticBuilderMethods for Builder<'a, 'll, 'tcx> {
         // Forward to the `get_static` method of `CodegenCx`
         self.cx().get_static(def_id)
     }
-
-    fn static_panic_location(&mut self, loc: &syntax::source_map::Loc) -> Self::Value {
-        let filename = Symbol::intern(&loc.file.name.to_string());
-        let filename = self.const_str(filename);
-        let line = self.const_u32(loc.line as u32);
-        let col = self.const_u32(loc.col.to_usize() as u32 + 1);
-        let struct_ = self.const_struct(&[filename.0, filename.1, line, col], false);
-
-        let align = self.tcx.data_layout.aggregate_align.abi
-            .max(self.tcx.data_layout.i32_align.abi)
-            .max(self.tcx.data_layout.pointer_align.abi);
-        // FIXME(eddyb) move this into miri, it can be correct if e.g. field order changes
-        self.static_addr_of(struct_, align, Some("panic_loc"))
-    }
 }
 
 impl Builder<'a, 'll, 'tcx> {

src/librustc_codegen_ssa/mir/block.rs

@@ -15,7 +15,7 @@ use crate::traits::*;
 
 use std::borrow::Cow;
 
-use syntax::symbol::Symbol;
+use syntax::{source_map::Span, symbol::Symbol};
 
 use super::{FunctionCx, LocalRef};
 use super::place::PlaceRef;
@@ -420,8 +420,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         self.set_debug_loc(&mut bx, terminator.source_info);
 
         // Get the location information.
-        let loc = bx.sess().source_map().lookup_char_pos(span.lo());
-        let location = bx.static_panic_location(&loc);
+        let location = self.get_caller_location(&mut bx, span).immediate();
 
         // Put together the arguments to the panic entry point.
         let (lang_item, args) = match msg {
@@ -534,11 +533,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             let ty = instance.unwrap().substs.type_at(0);
             let layout = bx.layout_of(ty);
             if layout.abi.is_uninhabited() {
-                let loc = bx.sess().source_map().lookup_char_pos(span.lo());
-
                 let msg_str = format!("Attempted to instantiate uninhabited type {}", ty);
                 let msg = bx.const_str(Symbol::intern(&msg_str));
-                let location = bx.static_panic_location(&loc);
+                let location = self.get_caller_location(&mut bx, span).immediate();
 
                 // Obtain the panic entry point.
                 let def_id =
@@ -584,13 +581,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
         if intrinsic == Some("caller_location") {
             if let Some((_, target)) = destination.as_ref() {
-                let loc = bx.sess().source_map().lookup_char_pos(span.lo());
-                let location = bx.static_panic_location(&loc);
+                let location = self.get_caller_location(&mut bx, span);
 
                 if let ReturnDest::IndirectOperand(tmp, _) = ret_dest {
-                    Immediate(location).store(&mut bx, tmp);
+                    location.val.store(&mut bx, tmp);
                 }
-                self.store_return(&mut bx, ret_dest, &fn_ty.ret, location);
+                self.store_return(&mut bx, ret_dest, &fn_ty.ret, location.immediate());
 
                 helper.maybe_sideeffect(self.mir, &mut bx, &[*target]);
                 helper.funclet_br(self, &mut bx, *target);
@@ -994,6 +990,20 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         }
     }
 
+    fn get_caller_location(
+        &mut self,
+        bx: &mut Bx,
+        span: Span,
+    ) -> OperandRef<'tcx, Bx::Value> {
+        let caller = bx.tcx().sess.source_map().lookup_char_pos(span.lo());
+        let const_loc = bx.tcx().const_caller_location((
+            Symbol::intern(&caller.file.name.to_string()),
+            caller.line as u32,
+            caller.col_display as u32 + 1,
+        ));
+        OperandRef::from_const(bx, const_loc)
+    }
+
     fn get_personality_slot(
         &mut self,
         bx: &mut Bx

src/librustc_codegen_ssa/traits/statics.rs

@@ -1,5 +1,4 @@
 use super::BackendTypes;
-use syntax::source_map::Loc;
 use rustc::hir::def_id::DefId;
 use rustc::ty::layout::Align;
 
@@ -10,5 +9,4 @@ pub trait StaticMethods: BackendTypes {
 
 pub trait StaticBuilderMethods: BackendTypes {
     fn get_static(&mut self, def_id: DefId) -> Self::Value;
-    fn static_panic_location(&mut self, loc: &Loc) -> Self::Value;
 }

src/librustc_mir/const_eval.rs

@@ -18,7 +18,7 @@ use rustc::traits::Reveal;
 use rustc_data_structures::fx::FxHashMap;
 use crate::interpret::eval_nullary_intrinsic;
 
-use syntax::source_map::{Span, DUMMY_SP};
+use syntax::{source_map::{Span, DUMMY_SP}, symbol::Symbol};
 
 use crate::interpret::{self,
     PlaceTy, MPlaceTy, OpTy, ImmTy, Immediate, Scalar, Pointer,
@@ -159,11 +159,7 @@ fn eval_body_using_ecx<'mir, 'tcx>(
     ecx.run()?;
 
     // Intern the result
-    intern_const_alloc_recursive(
-        ecx,
-        cid.instance.def_id(),
-        ret,
-    )?;
+    intern_const_alloc_recursive(ecx, tcx.static_mutability(cid.instance.def_id()), ret)?;
 
     debug!("eval_body_using_ecx done: {:?}", *ret);
     Ok(ret)

src/librustc_mir/interpret/intern.rs

@@ -6,7 +6,6 @@
 use rustc::ty::{Ty, self};
 use rustc::mir::interpret::{InterpResult, ErrorHandled};
 use rustc::hir;
-use rustc::hir::def_id::DefId;
 use super::validity::RefTracking;
 use rustc_data_structures::fx::FxHashSet;
 
@@ -270,12 +269,12 @@ for
 
 pub fn intern_const_alloc_recursive(
     ecx: &mut CompileTimeEvalContext<'mir, 'tcx>,
-    def_id: DefId,
+    // The `mutability` of the place, ignoring the type.
+    place_mut: Option<hir::Mutability>,
     ret: MPlaceTy<'tcx>,
 ) -> InterpResult<'tcx> {
     let tcx = ecx.tcx;
-    // this `mutability` is the mutability of the place, ignoring the type
-    let (base_mutability, base_intern_mode) = match tcx.static_mutability(def_id) {
+    let (base_mutability, base_intern_mode) = match place_mut {
         Some(hir::Mutability::MutImmutable) => (Mutability::Immutable, InternMode::Static),
         // `static mut` doesn't care about interior mutability, it's mutable anyway
         Some(hir::Mutability::MutMutable) => (Mutability::Mutable, InternMode::Static),

src/librustc_mir/interpret/intrinsics.rs

@@ -98,7 +98,13 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         let intrinsic_name = &self.tcx.item_name(instance.def_id()).as_str()[..];
         match intrinsic_name {
             "caller_location" => {
-                self.write_caller_location(span, dest)?;
+                let caller = self.tcx.sess.source_map().lookup_char_pos(span.lo());
+                let location = self.alloc_caller_location(
+                    Symbol::intern(&caller.file.name.to_string()),
+                    caller.line as u32,
+                    caller.col_display as u32 + 1,
+                )?;
+                self.write_scalar(location.ptr, dest)?;
             }
 
             "min_align_of" |

src/librustc_mir/interpret/intrinsics/caller_location.rs

@@ -2,23 +2,19 @@ use rustc::middle::lang_items::PanicLocationLangItem;
 use rustc::mir::interpret::{Pointer, PointerArithmetic, Scalar};
 use rustc::ty::subst::Subst;
 use rustc_target::abi::{LayoutOf, Size};
-use syntax_pos::Span;
+use syntax_pos::Symbol;
 
-use crate::interpret::{
-    MemoryKind,
-    intrinsics::{InterpCx, InterpResult, Machine, PlaceTy},
-};
+use crate::interpret::{MemoryKind, MPlaceTy, intrinsics::{InterpCx, InterpResult, Machine}};
 
 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
-    pub fn write_caller_location(
+    pub fn alloc_caller_location(
         &mut self,
-        span: Span,
-        dest: PlaceTy<'tcx, M::PointerTag>,
-    ) -> InterpResult<'tcx> {
-        let caller = self.tcx.sess.source_map().lookup_char_pos(span.lo());
-        let filename = caller.file.name.to_string();
-        let line = Scalar::from_u32(caller.line as u32);
-        let col = Scalar::from_u32(caller.col_display as u32 + 1);
+        filename: Symbol,
+        line: u32,
+        col: u32,
+    ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
+        let line = Scalar::from_u32(line);
+        let col = Scalar::from_u32(col);
 
         let ptr_size = self.pointer_size();
         let u32_size = Size::from_bits(32);
@@ -27,10 +23,10 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             .subst(*self.tcx, self.tcx.mk_substs([self.tcx.lifetimes.re_static.into()].iter()));
         let loc_layout = self.layout_of(loc_ty)?;
 
-        let file_alloc = self.tcx.allocate_bytes(filename.as_bytes());
+        let file_alloc = self.tcx.allocate_bytes(filename.as_str().as_bytes());
         let file_ptr = Pointer::new(file_alloc, Size::ZERO);
         let file = Scalar::Ptr(self.tag_static_base_pointer(file_ptr));
-        let file_len = Scalar::from_uint(filename.len() as u128, ptr_size);
+        let file_len = Scalar::from_uint(filename.as_str().len() as u128, ptr_size);
 
         let location = self.allocate(loc_layout, MemoryKind::Stack);
 
@@ -48,7 +44,6 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         alloc.write_scalar(layout, line_out, line.into(), u32_size)?;
         alloc.write_scalar(layout, col_out, col.into(), u32_size)?;
 
-        self.write_scalar(location.ptr, dest)?;
-        Ok(())
+        Ok(location)
     }
 }

src/librustc_mir/lib.rs

@@ -58,6 +58,7 @@ pub fn provide(providers: &mut Providers<'_>) {
     providers.const_eval = const_eval::const_eval_provider;
     providers.const_eval_raw = const_eval::const_eval_raw_provider;
     providers.check_match = hair::pattern::check_match;
+    providers.const_caller_location = const_eval::const_caller_location;
     providers.const_field = |tcx, param_env_and_value| {
         let (param_env, (value, field)) = param_env_and_value.into_parts();
         const_eval::const_field(tcx, param_env, None, field, value)