Rollup merge of #73684 - richkadel:llvm-coverage-map-gen-2, r=wesleywiser

add spans to injected coverage counters, extract with CoverageData query

This is the next iteration on the Rust Coverage implementation, and follows PR #73488

@tmandry @wesleywiser

I came up with an approach for coverage spans, pushing them through the Call terminator as additional args so they can be extracted by the CoverageData query.

I'm using an IndexVec to store them in CoverageData such that there can be only one per index (even if parts of the MIR get duplicated during optimization).

If this approach works for you, I can quickly expand on this to build a separate IndexVec for counter expressions, using a separate call that will be ignored during code generation, but from which I can extract the counter expression values.

Let me know your thoughts. Thanks!

r? @tmandry

Rust compiler MCP rust-lang/compiler-team#278
Relevant issue: #34701 - Implement support for LLVMs code coverage instrumentation

1 files changed, 34 insertions, 1 deletions

diff --git a/src/libcore/intrinsics.rs b/src/libcore/intrinsics.rs
index 7206cbd198f..aff4e4a8d98 100644
--- a/src/libcore/intrinsics.rs
+++ b/src/libcore/intrinsics.rs
@@ -1958,7 +1958,40 @@ extern "rust-intrinsic" {
     /// generation.
     #[cfg(not(bootstrap))]
     #[lang = "count_code_region"]
-    pub fn count_code_region(index: u32);
+    pub fn count_code_region(index: u32, start_byte_pos: u32, end_byte_pos: u32);
+
+    /// Internal marker for code coverage expressions, injected into the MIR when the
+    /// "instrument-coverage" option is enabled. This intrinsic is not converted into a
+    /// backend intrinsic call, but its arguments are extracted during the production of a
+    /// "coverage map", which is injected into the generated code, as additional data.
+    /// This marker identifies a code region and two other counters or counter expressions
+    /// whose sum is the number of times the code region was executed.
+    #[cfg(not(bootstrap))]
+    pub fn coverage_counter_add(
+        index: u32,
+        left_index: u32,
+        right_index: u32,
+        start_byte_pos: u32,
+        end_byte_pos: u32,
+    );
+
+    /// This marker identifies a code region and two other counters or counter expressions
+    /// whose difference is the number of times the code region was executed.
+    /// (See `coverage_counter_add` for more information.)
+    #[cfg(not(bootstrap))]
+    pub fn coverage_counter_subtract(
+        index: u32,
+        left_index: u32,
+        right_index: u32,
+        start_byte_pos: u32,
+        end_byte_pos: u32,
+    );
+
+    /// This marker identifies a code region to be added to the "coverage map" to indicate source
+    /// code that can never be reached.
+    /// (See `coverage_counter_add` for more information.)
+    #[cfg(not(bootstrap))]
+    pub fn coverage_unreachable(start_byte_pos: u32, end_byte_pos: u32);
 
     /// See documentation of `<*const T>::guaranteed_eq` for details.
     #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]