Rollup of 11 pull requests

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -432,8 +432,6 @@ impl<'a> Linker for GccLinker<'a> {
         // insert it here.
         if self.sess.target.is_like_osx {
             self.linker_arg("-dead_strip");
-        } else if self.sess.target.is_like_solaris {
-            self.linker_arg("-zignore");
 
         // If we're building a dylib, we don't use --gc-sections because LLVM
         // has already done the best it can do, and we also don't want to
@@ -655,6 +653,10 @@ impl<'a> Linker for GccLinker<'a> {
     fn add_as_needed(&mut self) {
         if self.sess.target.linker_is_gnu {
             self.linker_arg("--as-needed");
+        } else if self.sess.target.is_like_solaris {
+            // -z ignore is the Solaris equivalent to the GNU ld --as-needed option
+            self.linker_arg("-z");
+            self.linker_arg("ignore");
         }
     }
 }

compiler/rustc_expand/src/config.rs

@@ -464,31 +464,9 @@ impl<'a> StripUnconfigured<'a> {
                     return true;
                 }
             };
-            let error = |span, msg, suggestion: &str| {
-                let mut err = self.sess.parse_sess.span_diagnostic.struct_span_err(span, msg);
-                if !suggestion.is_empty() {
-                    err.span_suggestion(
-                        span,
-                        "expected syntax is",
-                        suggestion.into(),
-                        Applicability::MaybeIncorrect,
-                    );
-                }
-                err.emit();
-                true
-            };
-            let span = meta_item.span;
-            match meta_item.meta_item_list() {
-                None => error(span, "`cfg` is not followed by parentheses", "cfg(/* predicate */)"),
-                Some([]) => error(span, "`cfg` predicate is not specified", ""),
-                Some([_, .., l]) => error(l.span(), "multiple `cfg` predicates are specified", ""),
-                Some([single]) => match single.meta_item() {
-                    Some(meta_item) => {
-                        attr::cfg_matches(meta_item, &self.sess.parse_sess, self.features)
-                    }
-                    None => error(single.span(), "`cfg` predicate key cannot be a literal", ""),
-                },
-            }
+            parse_cfg(&meta_item, &self.sess).map_or(true, |meta_item| {
+                attr::cfg_matches(&meta_item, &self.sess.parse_sess, self.features)
+            })
         })
     }
 
@@ -532,6 +510,32 @@ impl<'a> StripUnconfigured<'a> {
     }
 }
 
+pub fn parse_cfg<'a>(meta_item: &'a MetaItem, sess: &Session) -> Option<&'a MetaItem> {
+    let error = |span, msg, suggestion: &str| {
+        let mut err = sess.parse_sess.span_diagnostic.struct_span_err(span, msg);
+        if !suggestion.is_empty() {
+            err.span_suggestion(
+                span,
+                "expected syntax is",
+                suggestion.into(),
+                Applicability::HasPlaceholders,
+            );
+        }
+        err.emit();
+        None
+    };
+    let span = meta_item.span;
+    match meta_item.meta_item_list() {
+        None => error(span, "`cfg` is not followed by parentheses", "cfg(/* predicate */)"),
+        Some([]) => error(span, "`cfg` predicate is not specified", ""),
+        Some([_, .., l]) => error(l.span(), "multiple `cfg` predicates are specified", ""),
+        Some([single]) => match single.meta_item() {
+            Some(meta_item) => Some(meta_item),
+            None => error(single.span(), "`cfg` predicate key cannot be a literal", ""),
+        },
+    }
+}
+
 fn is_cfg(sess: &Session, attr: &Attribute) -> bool {
     sess.check_name(attr, sym::cfg)
 }

compiler/rustc_mir/src/transform/const_goto.rs

@@ -47,7 +47,7 @@ impl<'tcx> MirPass<'tcx> for ConstGoto {
         // if we applied optimizations, we potentially have some cfg to cleanup to
         // make it easier for further passes
         if should_simplify {
-            simplify_cfg(body);
+            simplify_cfg(tcx, body);
             simplify_locals(body, tcx);
         }
     }

compiler/rustc_mir/src/transform/deduplicate_blocks.rs

@@ -26,7 +26,7 @@ impl<'tcx> MirPass<'tcx> for DeduplicateBlocks {
         if has_opts_to_apply {
             let mut opt_applier = OptApplier { tcx, duplicates };
             opt_applier.visit_body(body);
-            simplify_cfg(body);
+            simplify_cfg(tcx, body);
         }
     }
 }

compiler/rustc_mir/src/transform/early_otherwise_branch.rs

@@ -164,7 +164,7 @@ impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
         // Since this optimization adds new basic blocks and invalidates others,
         // clean up the cfg to make it nicer for other passes
         if should_cleanup {
-            simplify_cfg(body);
+            simplify_cfg(tcx, body);
         }
     }
 }

compiler/rustc_mir/src/transform/generator.rs

@@ -964,7 +964,7 @@ fn create_generator_drop_shim<'tcx>(
 
     // Make sure we remove dead blocks to remove
     // unrelated code from the resume part of the function
-    simplify::remove_dead_blocks(&mut body);
+    simplify::remove_dead_blocks(tcx, &mut body);
 
     dump_mir(tcx, None, "generator_drop", &0, &body, |_, _| Ok(()));
 
@@ -1137,7 +1137,7 @@ fn create_generator_resume_function<'tcx>(
 
     // Make sure we remove dead blocks to remove
     // unrelated code from the drop part of the function
-    simplify::remove_dead_blocks(body);
+    simplify::remove_dead_blocks(tcx, body);
 
     dump_mir(tcx, None, "generator_resume", &0, body, |_, _| Ok(()));
 }

compiler/rustc_mir/src/transform/inline.rs

@@ -57,7 +57,7 @@ impl<'tcx> MirPass<'tcx> for Inline {
         if inline(tcx, body) {
             debug!("running simplify cfg on {:?}", body.source);
             CfgSimplifier::new(body).simplify();
-            remove_dead_blocks(body);
+            remove_dead_blocks(tcx, body);
         }
     }
 }

compiler/rustc_mir/src/transform/match_branches.rs

@@ -167,7 +167,7 @@ impl<'tcx> MirPass<'tcx> for MatchBranchSimplification {
         }
 
         if should_cleanup {
-            simplify_cfg(body);
+            simplify_cfg(tcx, body);
         }
     }
 }

compiler/rustc_mir/src/transform/multiple_return_terminators.rs

@@ -38,6 +38,6 @@ impl<'tcx> MirPass<'tcx> for MultipleReturnTerminators {
             }
         }
 
-        simplify::remove_dead_blocks(body)
+        simplify::remove_dead_blocks(tcx, body)
     }
 }

compiler/rustc_mir/src/transform/remove_unneeded_drops.rs

@@ -36,7 +36,7 @@ impl<'tcx> MirPass<'tcx> for RemoveUnneededDrops {
         // if we applied optimizations, we potentially have some cfg to cleanup to
         // make it easier for further passes
         if should_simplify {
-            simplify_cfg(body);
+            simplify_cfg(tcx, body);
         }
     }
 }

compiler/rustc_mir/src/transform/simplify.rs

@@ -29,6 +29,7 @@
 
 use crate::transform::MirPass;
 use rustc_index::vec::{Idx, IndexVec};
+use rustc_middle::mir::coverage::*;
 use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
@@ -46,9 +47,9 @@ impl SimplifyCfg {
     }
 }
 
-pub fn simplify_cfg(body: &mut Body<'_>) {
+pub fn simplify_cfg(tcx: TyCtxt<'tcx>, body: &mut Body<'_>) {
     CfgSimplifier::new(body).simplify();
-    remove_dead_blocks(body);
+    remove_dead_blocks(tcx, body);
 
     // FIXME: Should probably be moved into some kind of pass manager
     body.basic_blocks_mut().raw.shrink_to_fit();
@@ -59,9 +60,9 @@ impl<'tcx> MirPass<'tcx> for SimplifyCfg {
         Cow::Borrowed(&self.label)
     }
 
-    fn run_pass(&self, _tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         debug!("SimplifyCfg({:?}) - simplifying {:?}", self.label, body.source);
-        simplify_cfg(body);
+        simplify_cfg(tcx, body);
     }
 }
 
@@ -286,7 +287,7 @@ impl<'a, 'tcx> CfgSimplifier<'a, 'tcx> {
     }
 }
 
-pub fn remove_dead_blocks(body: &mut Body<'_>) {
+pub fn remove_dead_blocks(tcx: TyCtxt<'tcx>, body: &mut Body<'_>) {
     let reachable = traversal::reachable_as_bitset(body);
     let num_blocks = body.basic_blocks().len();
     if num_blocks == reachable.count() {
@@ -306,6 +307,11 @@ pub fn remove_dead_blocks(body: &mut Body<'_>) {
         }
         used_blocks += 1;
     }
+
+    if tcx.sess.instrument_coverage() {
+        save_unreachable_coverage(basic_blocks, used_blocks);
+    }
+
     basic_blocks.raw.truncate(used_blocks);
 
     for block in basic_blocks {
@@ -315,6 +321,32 @@ pub fn remove_dead_blocks(body: &mut Body<'_>) {
     }
 }
 
+fn save_unreachable_coverage(
+    basic_blocks: &mut IndexVec<BasicBlock, BasicBlockData<'_>>,
+    first_dead_block: usize,
+) {
+    // retain coverage info for dead blocks, so coverage reports will still
+    // report `0` executions for the uncovered code regions.
+    let mut dropped_coverage = Vec::new();
+    for dead_block in first_dead_block..basic_blocks.len() {
+        for statement in basic_blocks[BasicBlock::new(dead_block)].statements.iter() {
+            if let StatementKind::Coverage(coverage) = &statement.kind {
+                if let Some(code_region) = &coverage.code_region {
+                    dropped_coverage.push((statement.source_info, code_region.clone()));
+                }
+            }
+        }
+    }
+    for (source_info, code_region) in dropped_coverage {
+        basic_blocks[START_BLOCK].statements.push(Statement {
+            source_info,
+            kind: StatementKind::Coverage(box Coverage {
+                kind: CoverageKind::Unreachable,
+                code_region: Some(code_region),
+            }),
+        })
+    }
+}
 pub struct SimplifyLocals;
 
 impl<'tcx> MirPass<'tcx> for SimplifyLocals {

compiler/rustc_mir/src/transform/simplify_try.rs

@@ -558,7 +558,7 @@ impl<'tcx> MirPass<'tcx> for SimplifyBranchSame {
 
         if did_remove_blocks {
             // We have dead blocks now, so remove those.
-            simplify::remove_dead_blocks(body);
+            simplify::remove_dead_blocks(tcx, body);
         }
     }
 }

compiler/rustc_mir/src/transform/unreachable_prop.rs

@@ -60,7 +60,7 @@ impl MirPass<'_> for UnreachablePropagation {
         }
 
         if replaced {
-            simplify::remove_dead_blocks(body);
+            simplify::remove_dead_blocks(tcx, body);
         }
     }
 }