Add coverage tracking tool

See sailcov/README.md for a short description

Fix many location info bugs discovered by eyeballing output

3 files changed, 146 insertions, 0 deletions

diff --git a/lib/coverage/Cargo.toml b/lib/coverage/Cargo.toml
new file mode 100644
index 00000000..f4fdf1d7
--- /dev/null
+++ b/lib/coverage/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "sail-coverage"
+version = "0.1.0"
+authors = ["Alasdair <alasdair.armstrong@cl.cam.ac.uk>"]
+edition = "2018"
+
+[dependencies]
+lazy_static = "1.4.0"
+
+[lib]
+crate-type = ["staticlib"]
diff --git a/lib/coverage/Makefile b/lib/coverage/Makefile
new file mode 100644
index 00000000..55ed9fdc
--- /dev/null
+++ b/lib/coverage/Makefile
@@ -0,0 +1,3 @@
+libsail_coverage.a: src/*.rs Cargo.toml Makefile
+	cargo build --release
+	cp target/release/libsail_coverage.a .
diff --git a/lib/coverage/src/lib.rs b/lib/coverage/src/lib.rs
new file mode 100644
index 00000000..003f8b88
--- /dev/null
+++ b/lib/coverage/src/lib.rs
@@ -0,0 +1,132 @@
+extern crate lazy_static;
+use lazy_static::lazy_static;
+
+use std::collections::HashSet;
+use std::ffi::{CStr, CString};
+use std::fs::{OpenOptions, File};
+use std::io::Write;
+use std::os::raw::{c_char, c_int};
+use std::sync::Mutex;
+
+#[derive(Eq, PartialEq, Hash)]
+struct Span {
+    sail_file: CString,
+    line1: i32,
+    char1: i32,
+    line2: i32,
+    char2: i32,
+}
+
+lazy_static! {
+    static ref BRANCHES: Mutex<HashSet<Span>> = Mutex::new(HashSet::new());
+    static ref FUNCTIONS: Mutex<HashSet<Span>> = Mutex::new(HashSet::new());
+}
+
+fn function_entry(_function_name: &CStr, span: Span) {
+    FUNCTIONS.lock().unwrap().insert(span);
+}
+
+fn branch_taken(_branch_id: i32, span: Span) {
+    BRANCHES.lock().unwrap().insert(span);
+}
+
+fn branch_reached(_branch_id: i32, _span: Span) {
+    ()
+}
+
+fn write_locations(file: &mut File, kind: char, spans: &Mutex<HashSet<Span>>) -> bool {
+    for span in spans.lock().unwrap().iter() {
+        let res = write!(
+            file,
+            "{} \"{}\", {}, {}, {}, {}\n",
+            kind,
+            span.sail_file.to_string_lossy(),
+            span.line1,
+            span.char1,
+            span.line2,
+            span.char2,
+        );
+        if res.is_err() {
+            return false;
+        }
+    };
+    true
+}
+
+#[no_mangle]
+pub extern "C" fn sail_coverage_exit() -> c_int {
+    if let Ok(mut file) = OpenOptions::new().create(true).append(true).open("sail_coverage") {
+        if !write_locations(&mut file, 'B', &BRANCHES) {
+            return 1
+        }
+        if !write_locations(&mut file, 'F', &FUNCTIONS) {
+            return 1
+        }
+        0
+    } else {
+        1
+    }
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn sail_function_entry(
+    function_name: *const c_char,
+    sail_file: *const c_char,
+    l1: c_int,
+    c1: c_int,
+    l2: c_int,
+    c2: c_int,
+) {
+    function_entry(
+        CStr::from_ptr(function_name),
+        Span {
+            sail_file: CStr::from_ptr(sail_file).into(),
+            line1: l1 as i32,
+            char1: c1 as i32,
+            line2: l2 as i32,
+            char2: c2 as i32,
+        },
+    )
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn sail_branch_taken(
+    branch_id: c_int,
+    sail_file: *const c_char,
+    l1: c_int,
+    c1: c_int,
+    l2: c_int,
+    c2: c_int,
+) {
+    branch_taken(
+        branch_id as i32,
+        Span {
+            sail_file: CStr::from_ptr(sail_file).into(),
+            line1: l1 as i32,
+            char1: c1 as i32,
+            line2: l2 as i32,
+            char2: c2 as i32,
+        },
+    )
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn sail_branch_reached(
+    branch_id: c_int,
+    sail_file: *const c_char,
+    l1: c_int,
+    c1: c_int,
+    l2: c_int,
+    c2: c_int,
+) {
+    branch_reached(
+        branch_id as i32,
+        Span {
+            sail_file: CStr::from_ptr(sail_file).into(),
+            line1: l1 as i32,
+            char1: c1 as i32,
+            line2: l2 as i32,
+            char2: c2 as i32,
+        },
+    )
+}