Auto merge of #43107 - michaelwoerister:less-span-info-in-debug, r=ni…

…komatsakis

incr.comp.: Don't include span information in the ICH of type definitions

This should improve some of the `regex` tests on perf.rlo. Not including spans into the ICH is harmless until we also cache warnings. To really solve the problem, we need to do more refactoring (see #43088).

r? @nikomatsakis

src/librustc/ich/impls_hir.rs

@@ -895,25 +895,28 @@ impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for hir::I
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
                                           hasher: &mut StableHasher<W>) {
-        let node_id_hashing_mode = match self.node {
-            hir::ItemExternCrate(..) |
+        let (node_id_hashing_mode, hash_spans) = match self.node {
             hir::ItemStatic(..)      |
             hir::ItemConst(..)       |
-            hir::ItemFn(..)          |
-            hir::ItemMod(..)         |
+            hir::ItemFn(..)          => {
+                (NodeIdHashingMode::Ignore, hcx.hash_spans())
+            }
+            hir::ItemUse(..) => {
+                (NodeIdHashingMode::HashTraitsInScope, false)
+            }
+
+            hir::ItemExternCrate(..) |
             hir::ItemForeignMod(..)  |
             hir::ItemGlobalAsm(..)   |
+            hir::ItemMod(..)         |
+            hir::ItemDefaultImpl(..) |
+            hir::ItemTrait(..)       |
+            hir::ItemImpl(..)        |
             hir::ItemTy(..)          |
             hir::ItemEnum(..)        |
             hir::ItemStruct(..)      |
-            hir::ItemUnion(..)       |
-            hir::ItemTrait(..)       |
-            hir::ItemDefaultImpl(..) |
-            hir::ItemImpl(..)        => {
-                NodeIdHashingMode::Ignore
-            }
-            hir::ItemUse(..) => {
-                NodeIdHashingMode::HashTraitsInScope
+            hir::ItemUnion(..)       => {
+                (NodeIdHashingMode::Ignore, false)
             }
         };
 
@@ -927,14 +930,16 @@ impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for hir::I
         } = *self;
 
         hcx.hash_hir_item_like(attrs, |hcx| {
-            hcx.with_node_id_hashing_mode(node_id_hashing_mode, |hcx| {
-                id.hash_stable(hcx, hasher);
+            hcx.while_hashing_spans(hash_spans, |hcx| {
+                hcx.with_node_id_hashing_mode(node_id_hashing_mode, |hcx| {
+                    id.hash_stable(hcx, hasher);
+                });
+                name.hash_stable(hcx, hasher);
+                attrs.hash_stable(hcx, hasher);
+                node.hash_stable(hcx, hasher);
+                vis.hash_stable(hcx, hasher);
+                span.hash_stable(hcx, hasher);
             });
-            name.hash_stable(hcx, hasher);
-            attrs.hash_stable(hcx, hasher);
-            node.hash_stable(hcx, hasher);
-            vis.hash_stable(hcx, hasher);
-            span.hash_stable(hcx, hasher);
         });
     }
 }

src/librustc_trans/debuginfo/metadata.rs

@@ -14,7 +14,7 @@ use self::MemberDescriptionFactory::*;
 use self::EnumDiscriminantInfo::*;
 
 use super::utils::{debug_context, DIB, span_start, bytes_to_bits, size_and_align_of,
-                   get_namespace_and_span_for_item, create_DIArray, is_node_local_to_unit};
+                   get_namespace_for_item, create_DIArray, is_node_local_to_unit};
 use super::namespace::mangled_name_of_item;
 use super::type_names::compute_debuginfo_type_name;
 use super::{CrateDebugContext};
@@ -421,7 +421,7 @@ fn trait_pointer_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
     let containing_scope = match trait_type.sty {
         ty::TyDynamic(ref data, ..) => if let Some(principal) = data.principal() {
             let def_id = principal.def_id();
-            get_namespace_and_span_for_item(cx, def_id).0
+            get_namespace_for_item(cx, def_id)
         } else {
             NO_SCOPE_METADATA
         },
@@ -971,7 +971,7 @@ fn prepare_struct_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
         _ => bug!("prepare_struct_metadata on a non-ADT")
     };
 
-    let (containing_scope, _) = get_namespace_and_span_for_item(cx, struct_def_id);
+    let containing_scope = get_namespace_for_item(cx, struct_def_id);
 
     let struct_metadata_stub = create_struct_stub(cx,
                                                   struct_llvm_type,
@@ -1096,7 +1096,7 @@ fn prepare_union_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
         _ => bug!("prepare_union_metadata on a non-ADT")
     };
 
-    let (containing_scope, _) = get_namespace_and_span_for_item(cx, union_def_id);
+    let containing_scope = get_namespace_for_item(cx, union_def_id);
 
     let union_metadata_stub = create_union_stub(cx,
                                                 union_llvm_type,
@@ -1483,7 +1483,7 @@ fn prepare_enum_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                                    -> RecursiveTypeDescription<'tcx> {
     let enum_name = compute_debuginfo_type_name(cx, enum_type, false);
 
-    let (containing_scope, _) = get_namespace_and_span_for_item(cx, enum_def_id);
+    let containing_scope = get_namespace_for_item(cx, enum_def_id);
     // FIXME: This should emit actual file metadata for the enum, but we
     // currently can't get the necessary information when it comes to types
     // imported from other crates. Formerly we violated the ODR when performing
@@ -1781,7 +1781,8 @@ pub fn create_global_var_metadata(cx: &CrateContext,
     let tcx = cx.tcx();
 
     let node_def_id = tcx.hir.local_def_id(node_id);
-    let (var_scope, span) = get_namespace_and_span_for_item(cx, node_def_id);
+    let var_scope = get_namespace_for_item(cx, node_def_id);
+    let span = cx.tcx().def_span(node_def_id);
 
     let (file_metadata, line_number) = if span != syntax_pos::DUMMY_SP {
         let loc = span_start(cx, span);

src/librustc_trans/debuginfo/namespace.rs

@@ -10,19 +10,17 @@
 
 // Namespace Handling.
 
-use super::metadata::{file_metadata, unknown_file_metadata, UNKNOWN_LINE_NUMBER};
-use super::utils::{DIB, debug_context, span_start};
+use super::metadata::{unknown_file_metadata, UNKNOWN_LINE_NUMBER};
+use super::utils::{DIB, debug_context};
 
 use llvm;
 use llvm::debuginfo::DIScope;
 use rustc::hir::def_id::DefId;
 use rustc::hir::map::DefPathData;
 use common::CrateContext;
 
-use libc::c_uint;
 use std::ffi::CString;
 use std::ptr;
-use syntax_pos::DUMMY_SP;
 
 pub fn mangled_name_of_item(ccx: &CrateContext, def_id: DefId, extra: &str) -> String {
     fn fill_nested(ccx: &CrateContext, def_id: DefId, extra: &str, output: &mut String) {
@@ -69,21 +67,14 @@ pub fn item_namespace(ccx: &CrateContext, def_id: DefId) -> DIScope {
     };
 
     let namespace_name = CString::new(namespace_name.as_bytes()).unwrap();
-    let span = ccx.tcx().def_span(def_id);
-    let (file, line) = if span != DUMMY_SP {
-        let loc = span_start(ccx, span);
-        (file_metadata(ccx, &loc.file.name, def_id.krate), loc.line as c_uint)
-    } else {
-        (unknown_file_metadata(ccx), UNKNOWN_LINE_NUMBER)
-    };
 
     let scope = unsafe {
         llvm::LLVMRustDIBuilderCreateNameSpace(
             DIB(ccx),
             parent_scope,
             namespace_name.as_ptr(),
-            file,
-            line as c_uint)
+            unknown_file_metadata(ccx),
+            UNKNOWN_LINE_NUMBER)
     };
 
     debug_context(ccx).namespace_map.borrow_mut().insert(def_id, scope);

src/librustc_trans/debuginfo/utils.rs

@@ -73,13 +73,7 @@ pub fn DIB(cx: &CrateContext) -> DIBuilderRef {
     cx.dbg_cx().as_ref().unwrap().builder
 }
 
-pub fn get_namespace_and_span_for_item(cx: &CrateContext, def_id: DefId)
-                                   -> (DIScope, Span) {
-    let containing_scope = item_namespace(cx, cx.tcx().parent(def_id)
-        .expect("get_namespace_and_span_for_item: missing parent?"));
-
-    // Try to get some span information, if we have an inlined item.
-    let definition_span = cx.tcx().def_span(def_id);
-
-    (containing_scope, definition_span)
+pub fn get_namespace_for_item(cx: &CrateContext, def_id: DefId) -> DIScope {
+    item_namespace(cx, cx.tcx().parent(def_id)
+        .expect("get_namespace_for_item: missing parent?"))
 }

src/test/incremental/spans_in_type_debuginfo.rs

@@ -0,0 +1,63 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test that moving a type definition within a source file does not affect
+// re-compilation.
+
+// revisions:rpass1 rpass2
+// compile-flags: -Z query-dep-graph -g
+
+#![rustc_partition_reused(module="spans_in_type_debuginfo", cfg="rpass2")]
+#![rustc_partition_reused(module="spans_in_type_debuginfo-structs", cfg="rpass2")]
+#![rustc_partition_reused(module="spans_in_type_debuginfo-enums", cfg="rpass2")]
+
+#![feature(rustc_attrs)]
+
+mod structs {
+    #[cfg(rpass1)]
+    pub struct X {
+        pub x: u32,
+    }
+
+    #[cfg(rpass2)]
+    pub struct X {
+        pub x: u32,
+    }
+
+    pub fn foo(x: X) -> u32 {
+        x.x
+    }
+}
+
+mod enums {
+    #[cfg(rpass1)]
+    pub enum X {
+        A { x: u32 },
+        B(u32),
+    }
+
+    #[cfg(rpass2)]
+    pub enum X {
+        A { x: u32 },
+        B(u32),
+    }
+
+    pub fn foo(x: X) -> u32 {
+        match x {
+            X::A { x } => x,
+            X::B(x) => x,
+        }
+    }
+}
+
+pub fn main() {
+    let _ = structs::foo(structs::X { x: 1 });
+    let _ = enums::foo(enums::X::A { x: 2 });
+}