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-rw-r--r--compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs43
-rw-r--r--compiler/rustc_codegen_llvm/src/llvm/ffi.rs42
-rw-r--r--compiler/rustc_codegen_ssa/src/coverageinfo/ffi.rs8
-rw-r--r--compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp9
-rw-r--r--compiler/rustc_middle/src/mir/coverage.rs6
5 files changed, 86 insertions, 22 deletions
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
index 6830864ba04..0390caaec33 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
@@ -9,6 +9,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
 use rustc_hir::def_id::{DefId, DefIdSet};
 use rustc_llvm::RustString;
 use rustc_middle::mir::coverage::CodeRegion;
+use rustc_middle::ty::TyCtxt;
 use rustc_span::Symbol;
 
 use std::ffi::CString;
@@ -17,10 +18,11 @@ use tracing::debug;
 
 /// Generates and exports the Coverage Map.
 ///
-/// This Coverage Map complies with Coverage Mapping Format version 4 (zero-based encoded as 3),
-/// as defined at [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format)
-/// and published in Rust's November 2020 fork of LLVM. This version is supported by the LLVM
-/// coverage tools (`llvm-profdata` and `llvm-cov`) bundled with Rust's fork of LLVM.
+/// Rust Coverage Map generation supports LLVM Coverage Mapping Format versions
+/// 5 (LLVM 12, only) and 6 (zero-based encoded as 4 and 5, respectively), as defined at
+/// [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
+/// These versions are supported by the LLVM coverage tools (`llvm-profdata` and `llvm-cov`)
+/// bundled with Rust's fork of LLVM.
 ///
 /// Consequently, Rust's bundled version of Clang also generates Coverage Maps compliant with
 /// the same version. Clang's implementation of Coverage Map generation was referenced when
@@ -30,11 +32,12 @@ use tracing::debug;
 pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
     let tcx = cx.tcx;
 
-    // Ensure LLVM supports Coverage Map Version 4 (encoded as a zero-based value: 3).
-    // If not, the LLVM Version must be less than 11.
+    // Ensure the installed version of LLVM supports at least Coverage Map
+    // Version 5 (encoded as a zero-based value: 4), which was introduced with
+    // LLVM 12.
     let version = coverageinfo::mapping_version();
-    if version != 3 {
-        tcx.sess.fatal("rustc option `-Z instrument-coverage` requires LLVM 11 or higher.");
+    if version < 4 {
+        tcx.sess.fatal("rustc option `-Z instrument-coverage` requires LLVM 12 or higher.");
     }
 
     debug!("Generating coverage map for CodegenUnit: `{}`", cx.codegen_unit.name());
@@ -57,7 +60,7 @@ pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
         return;
     }
 
-    let mut mapgen = CoverageMapGenerator::new();
+    let mut mapgen = CoverageMapGenerator::new(tcx, version);
 
     // Encode coverage mappings and generate function records
     let mut function_data = Vec::new();
@@ -112,8 +115,26 @@ struct CoverageMapGenerator {
 }
 
 impl CoverageMapGenerator {
-    fn new() -> Self {
-        Self { filenames: FxIndexSet::default() }
+    fn new(tcx: TyCtxt<'_>, version: u32) -> Self {
+        let mut filenames = FxIndexSet::default();
+        if version >= 5 {
+            // LLVM Coverage Mapping Format version 6 (zero-based encoded as 5)
+            // requires setting the first filename to the compilation directory.
+            // Since rustc generates coverage maps with relative paths, the
+            // compilation directory can be combined with the the relative paths
+            // to get absolute paths, if needed.
+            let working_dir = tcx
+                .sess
+                .opts
+                .working_dir
+                .remapped_path_if_available()
+                .to_string_lossy()
+                .to_string();
+            let c_filename =
+                CString::new(working_dir).expect("null error converting filename to C string");
+            filenames.insert(c_filename);
+        }
+        Self { filenames }
     }
 
     /// Using the `expressions` and `counter_regions` collected for the current function, generate
diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 6eb0fb56046..2ef4c871825 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -685,7 +685,7 @@ pub type InlineAsmDiagHandlerTy = unsafe extern "C" fn(&SMDiagnostic, *const c_v
 pub mod coverageinfo {
     use super::coverage_map;
 
-    /// Aligns with [llvm::coverage::CounterMappingRegion::RegionKind](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L206-L222)
+    /// Aligns with [llvm::coverage::CounterMappingRegion::RegionKind](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L209-L230)
     #[derive(Copy, Clone, Debug)]
     #[repr(C)]
     pub enum RegionKind {
@@ -704,11 +704,16 @@ pub mod coverageinfo {
         /// A GapRegion is like a CodeRegion, but its count is only set as the
         /// line execution count when its the only region in the line.
         GapRegion = 3,
+
+        /// A BranchRegion represents leaf-level boolean expressions and is
+        /// associated with two counters, each representing the number of times the
+        /// expression evaluates to true or false.
+        BranchRegion = 4,
     }
 
     /// This struct provides LLVM's representation of a "CoverageMappingRegion", encoded into the
     /// coverage map, in accordance with the
-    /// [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
+    /// [LLVM Code Coverage Mapping Format](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#llvm-code-coverage-mapping-format).
     /// The struct composes fields representing the `Counter` type and value(s) (injected counter
     /// ID, or expression type and operands), the source file (an indirect index into a "filenames
     /// array", encoded separately), and source location (start and end positions of the represented
@@ -721,6 +726,10 @@ pub mod coverageinfo {
         /// The counter type and type-dependent counter data, if any.
         counter: coverage_map::Counter,
 
+        /// If the `RegionKind` is a `BranchRegion`, this represents the counter
+        /// for the false branch of the region.
+        false_counter: coverage_map::Counter,
+
         /// An indirect reference to the source filename. In the LLVM Coverage Mapping Format, the
         /// file_id is an index into a function-specific `virtual_file_mapping` array of indexes
         /// that, in turn, are used to look up the filename for this region.
@@ -758,6 +767,7 @@ pub mod coverageinfo {
         ) -> Self {
             Self {
                 counter,
+                false_counter: coverage_map::Counter::zero(),
                 file_id,
                 expanded_file_id: 0,
                 start_line,
@@ -771,6 +781,31 @@ pub mod coverageinfo {
         // This function might be used in the future; the LLVM API is still evolving, as is coverage
         // support.
         #[allow(dead_code)]
+        crate fn branch_region(
+            counter: coverage_map::Counter,
+            false_counter: coverage_map::Counter,
+            file_id: u32,
+            start_line: u32,
+            start_col: u32,
+            end_line: u32,
+            end_col: u32,
+        ) -> Self {
+            Self {
+                counter,
+                false_counter,
+                file_id,
+                expanded_file_id: 0,
+                start_line,
+                start_col,
+                end_line,
+                end_col,
+                kind: RegionKind::BranchRegion,
+            }
+        }
+
+        // This function might be used in the future; the LLVM API is still evolving, as is coverage
+        // support.
+        #[allow(dead_code)]
         crate fn expansion_region(
             file_id: u32,
             expanded_file_id: u32,
@@ -781,6 +816,7 @@ pub mod coverageinfo {
         ) -> Self {
             Self {
                 counter: coverage_map::Counter::zero(),
+                false_counter: coverage_map::Counter::zero(),
                 file_id,
                 expanded_file_id,
                 start_line,
@@ -803,6 +839,7 @@ pub mod coverageinfo {
         ) -> Self {
             Self {
                 counter: coverage_map::Counter::zero(),
+                false_counter: coverage_map::Counter::zero(),
                 file_id,
                 expanded_file_id: 0,
                 start_line,
@@ -826,6 +863,7 @@ pub mod coverageinfo {
         ) -> Self {
             Self {
                 counter,
+                false_counter: coverage_map::Counter::zero(),
                 file_id,
                 expanded_file_id: 0,
                 start_line,
diff --git a/compiler/rustc_codegen_ssa/src/coverageinfo/ffi.rs b/compiler/rustc_codegen_ssa/src/coverageinfo/ffi.rs
index 962c01c2ee7..e288760a02b 100644
--- a/compiler/rustc_codegen_ssa/src/coverageinfo/ffi.rs
+++ b/compiler/rustc_codegen_ssa/src/coverageinfo/ffi.rs
@@ -1,6 +1,6 @@
 use rustc_middle::mir::coverage::{CounterValueReference, MappedExpressionIndex};
 
-/// Aligns with [llvm::coverage::Counter::CounterKind](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L206-L222)
+/// Aligns with [llvm::coverage::Counter::CounterKind](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L95)
 #[derive(Copy, Clone, Debug)]
 #[repr(C)]
 pub enum CounterKind {
@@ -17,7 +17,7 @@ pub enum CounterKind {
 ///     `instrprof.increment()`)
 ///   * For `CounterKind::Expression`, `id` is the index into the coverage map's array of
 ///     counter expressions.
-/// Aligns with [llvm::coverage::Counter](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L99-L100)
+/// Aligns with [llvm::coverage::Counter](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L102-L103)
 /// Important: The Rust struct layout (order and types of fields) must match its C++ counterpart.
 #[derive(Copy, Clone, Debug)]
 #[repr(C)]
@@ -59,7 +59,7 @@ impl Counter {
     }
 }
 
-/// Aligns with [llvm::coverage::CounterExpression::ExprKind](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L147)
+/// Aligns with [llvm::coverage::CounterExpression::ExprKind](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L150)
 #[derive(Copy, Clone, Debug)]
 #[repr(C)]
 pub enum ExprKind {
@@ -67,7 +67,7 @@ pub enum ExprKind {
     Add = 1,
 }
 
-/// Aligns with [llvm::coverage::CounterExpression](https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L148-L149)
+/// Aligns with [llvm::coverage::CounterExpression](https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h#L151-L152)
 /// Important: The Rust struct layout (order and types of fields) must match its C++
 /// counterpart.
 #[derive(Copy, Clone, Debug)]
diff --git a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
index 8cd2bd12450..154f554d607 100644
--- a/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/CoverageMappingWrapper.cpp
@@ -10,6 +10,7 @@ using namespace llvm;
 
 struct LLVMRustCounterMappingRegion {
   coverage::Counter Count;
+  coverage::Counter FalseCount;
   uint32_t FileID;
   uint32_t ExpandedFileID;
   uint32_t LineStart;
@@ -53,7 +54,7 @@ extern "C" void LLVMRustCoverageWriteMappingToBuffer(
   MappingRegions.reserve(NumMappingRegions);
   for (const auto &Region : makeArrayRef(RustMappingRegions, NumMappingRegions)) {
     MappingRegions.emplace_back(
-        Region.Count, Region.FileID, Region.ExpandedFileID,
+        Region.Count, Region.FalseCount, Region.FileID, Region.ExpandedFileID,
         Region.LineStart, Region.ColumnStart, Region.LineEnd, Region.ColumnEnd,
         Region.Kind);
   }
@@ -108,5 +109,9 @@ extern "C" void LLVMRustCoverageWriteMappingVarNameToString(RustStringRef Str) {
 }
 
 extern "C" uint32_t LLVMRustCoverageMappingVersion() {
-  return coverage::CovMapVersion::Version4;
+#if LLVM_VERSION_GE(13, 0)
+  return coverage::CovMapVersion::Version6;
+#else
+  return coverage::CovMapVersion::Version5;
+#endif
 }
diff --git a/compiler/rustc_middle/src/mir/coverage.rs b/compiler/rustc_middle/src/mir/coverage.rs
index ddb1a84fe7b..640d3a5a02b 100644
--- a/compiler/rustc_middle/src/mir/coverage.rs
+++ b/compiler/rustc_middle/src/mir/coverage.rs
@@ -21,9 +21,9 @@ rustc_index::newtype_index! {
 impl ExpressionOperandId {
     /// An expression operand for a "zero counter", as described in the following references:
     ///
-    /// * <https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#counter>
-    /// * <https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#tag>
-    /// * <https://github.com/rust-lang/llvm-project/blob/rustc/11.0-2020-10-12/llvm/docs/CoverageMappingFormat.rst#counter-expressions>
+    /// * <https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#counter>
+    /// * <https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#tag>
+    /// * <https://github.com/rust-lang/llvm-project/blob/rustc/13.0-2021-09-30/llvm/docs/CoverageMappingFormat.rst#counter-expressions>
     ///
     /// This operand can be used to count two or more separate code regions with a single counter,
     /// if they run sequentially with no branches, by injecting the `Counter` in a `BasicBlock` for