Fix storing coverage data in cargo projects

kani-driver/src/coverage/cov_session.rs

@@ -18,7 +18,7 @@ impl KaniSession {
     /// Note: Currently, coverage mappings are not included due to technical
     /// limitations. But this is where we should save them.
     pub fn save_coverage_metadata(&self, project: &Project, stamp: &String) -> Result<()> {
-        if self.args.target_dir.is_some() {
+        if project.input.is_none() {
             self.save_coverage_metadata_cargo(project, stamp)
         } else {
             self.save_coverage_metadata_standalone(project, stamp)
@@ -97,7 +97,7 @@ impl KaniSession {
         results: &Vec<HarnessResult>,
         stamp: &String,
     ) -> Result<()> {
-        if self.args.target_dir.is_some() {
+        if project.input.is_none() {
             self.save_coverage_results_cargo(results, stamp)
         } else {
             self.save_coverage_results_standalone(project, results, stamp)

scripts/kani-regression.sh

@@ -60,6 +60,7 @@ TESTS=(
     "cargo-ui cargo-kani"
     "script-based-pre exec"
     "coverage coverage-based"
+    "cargo-coverage cargo-coverage"
     "kani-docs cargo-kani"
     "kani-fixme kani-fixme"
 )

tests/cargo-coverage/simple-lib/Cargo.toml

@@ -0,0 +1,10 @@
+# Copyright Kani Contributors
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+[package]
+name = "simple-lib"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+
+[workspace]

tests/cargo-coverage/simple-lib/src/lib.rs

@@ -0,0 +1,25 @@
+// Copyright Kani Contributors
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+pub mod pair;
+pub use pair::Pair;
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}
+
+#[cfg(kani)]
+mod kani_tests {
+    use super::*;
+
+    #[kani::proof]
+    fn test_sum() {
+        let a: u64 = kani::any();
+        let b: u64 = kani::any();
+        let p = Pair::new(a, b);
+        assert!(p.sum() == a.wrapping_add(b));
+    }
+}

tests/cargo-coverage/simple-lib/src/pair.rs

@@ -0,0 +1,33 @@
+// Copyright Kani Contributors
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+pub struct Pair(pub u64, pub u64);
+
+impl Pair {
+    pub fn new(a: u64, b: u64) -> Self {
+        Pair(a, b)
+    }
+    pub fn sum(&self) -> u64 {
+        self.0.wrapping_add(self.1)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn one_plus_two() {
+        let p = Pair::new(1, 2);
+        assert_eq!(p.sum(), 3);
+    }
+}
+
+#[cfg(kani)]
+mod kani_tests {
+    use super::*;
+
+    #[kani::proof]
+    fn test_one_plus_two() {
+        let p = Pair::new(1, 2);
+        assert!(p.sum() == 3);
+    }
+}

tests/cargo-coverage/simple-lib/test_one_plus_two.expected

@@ -0,0 +1,10 @@
+Source-based code coverage results:
+
+src/pair.rs (pair::Pair::new)\
+ * 6:5 - 8:6 COVERED
+
+src/pair.rs (pair::Pair::sum)\
+ * 9:5 - 11:6 COVERED
+
+src/pair.rs (pair::kani_tests::test_one_plus_two)\
+ * 29:5 - 32:6 COVERED

tests/cargo-coverage/simple-lib/test_sum.expected

@@ -0,0 +1,10 @@
+Source-based code coverage results:
+
+src/lib.rs (kani_tests::test_sum)\
+ * 19:5 - 24:6 COVERED
+
+src/pair.rs (pair::Pair::new)\
+ * 6:5 - 8:6 COVERED
+
+src/pair.rs (pair::Pair::sum)\
+ * 9:5 - 11:6 COVERED

tools/compiletest/src/common.rs

@@ -17,6 +17,7 @@ use test::ColorConfig;
 pub enum Mode {
     Kani,
     KaniFixme,
+    CargoCoverage,
     CargoKani,
     CargoKaniTest, // `cargo kani --tests`. This is temporary and should be removed when s2n-quic moves --tests to `Cargo.toml`.
     CoverageBased,
@@ -34,6 +35,7 @@ impl FromStr for Mode {
             "cargo-kani" => Ok(CargoKani),
             "cargo-kani-test" => Ok(CargoKaniTest),
             "coverage-based" => Ok(CoverageBased),
+            "cargo-coverage" => Ok(CargoCoverage),
             "exec" => Ok(Exec),
             "expected" => Ok(Expected),
             "stub-tests" => Ok(Stub),
@@ -47,6 +49,7 @@ impl fmt::Display for Mode {
         let s = match *self {
             Kani => "kani",
             KaniFixme => "kani-fixme",
+            CargoCoverage => "cargo-coverage",
             CargoKani => "cargo-kani",
             CargoKaniTest => "cargo-kani-test",
             CoverageBased => "coverage-based",

tools/compiletest/src/main.rs

@@ -349,7 +349,7 @@ fn collect_tests_from_dir(
     tests: &mut Vec<test::TestDescAndFn>,
 ) -> io::Result<()> {
     match config.mode {
-        Mode::CargoKani | Mode::CargoKaniTest => {
+        Mode::CargoCoverage | Mode::CargoKani | Mode::CargoKaniTest => {
             collect_expected_tests_from_dir(config, dir, relative_dir_path, inputs, tests)
         }
         Mode::Exec => collect_exec_tests_from_dir(config, dir, relative_dir_path, inputs, tests),
@@ -378,7 +378,11 @@ fn collect_expected_tests_from_dir(
     // output directory corresponding to each to avoid race conditions during
     // the testing phase. We immediately return after adding the tests to avoid
     // treating `*.rs` files as tests.
-    assert!(config.mode == Mode::CargoKani || config.mode == Mode::CargoKaniTest);
+    assert!(
+        config.mode == Mode::CargoCoverage
+            || config.mode == Mode::CargoKani
+            || config.mode == Mode::CargoKaniTest
+    );
 
     let has_cargo_toml = dir.join("Cargo.toml").exists();
     for file in fs::read_dir(dir)? {

tools/compiletest/src/runtest.rs

@@ -8,7 +8,7 @@
 use crate::common::KaniFailStep;
 use crate::common::{output_base_dir, output_base_name};
 use crate::common::{
-    CargoKani, CargoKaniTest, CoverageBased, Exec, Expected, Kani, KaniFixme, Stub,
+    CargoCoverage, CargoKani, CargoKaniTest, CoverageBased, Exec, Expected, Kani, KaniFixme, Stub,
 };
 use crate::common::{Config, TestPaths};
 use crate::header::TestProps;
@@ -74,6 +74,7 @@ impl<'test> TestCx<'test> {
         match self.config.mode {
             Kani => self.run_kani_test(),
             KaniFixme => self.run_kani_test(),
+            CargoCoverage => self.run_cargo_coverage_test(),
             CargoKani => self.run_cargo_kani_test(false),
             CargoKaniTest => self.run_cargo_kani_test(true),
             CoverageBased => self.run_expected_coverage_test(),
@@ -313,7 +314,7 @@ impl<'test> TestCx<'test> {
         self.compose_and_run(kani)
     }
 
-    /// Run coverage based output for kani on a single file
+    /// Run Kani with coverage enabled on a single source file
     fn run_kani_with_coverage(&self) -> ProcRes {
         let mut kani = Command::new("kani");
         if !self.props.compile_flags.is_empty() {
@@ -329,6 +330,34 @@ impl<'test> TestCx<'test> {
         self.compose_and_run(kani)
     }
 
+    /// Run Kani with coverage enabled on a cargo package
+    fn run_cargo_coverage_test(&self) {
+        // We create our own command for the same reasons listed in `run_kani_test` method.
+        let mut cargo = Command::new("cargo");
+        // We run `cargo` on the directory where we found the `*.expected` file
+        let parent_dir = self.testpaths.file.parent().unwrap();
+        // The name of the function to test is the same as the stem of `*.expected` file
+        let function_name = self.testpaths.file.file_stem().unwrap().to_str().unwrap();
+        cargo
+            .arg("kani")
+            .arg("--coverage")
+            .arg("-Zsource-coverage")
+            .arg("--target-dir")
+            .arg(self.output_base_dir().join("target"))
+            .current_dir(parent_dir);
+
+        if "expected" != self.testpaths.file.file_name().unwrap() {
+            cargo.args(["--harness", function_name]);
+        }
+        cargo.args(&self.config.extra_args);
+
+        let proc_res = self.compose_and_run(cargo);
+        self.verify_output(&proc_res, &self.testpaths.file);
+
+        // TODO: We should probably be checking the exit status somehow
+        // See https://github.com/model-checking/kani/issues/1895
+    }
+
     /// Runs an executable file and:
     ///  * Checks the expected output if an expected file is specified
     ///  * Checks the exit code (assumed to be 0 by default)