Record coverage using debuggable-module (#2701)

src/agent/Cargo.toml

@@ -1,6 +1,7 @@
 [workspace]
 members = [
     "atexit",
+    "coverage",
     "coverage-legacy",
     "debuggable-module",
     "debugger",

src/agent/coverage/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "coverage"
+version = "0.1.0"
+edition = "2021"
+license = "MIT"
+
+[dependencies]
+anyhow = "1.0"
+debuggable-module = { path = "../debuggable-module" }
+iced-x86 = "1.17"
+log = "0.4.17"
+regex = "1.0"
+symbolic = { version = "10.1", features = ["debuginfo", "demangle", "symcache"] }
+thiserror = "1.0"
+
+[target.'cfg(target_os = "windows")'.dependencies]
+debugger = { path = "../debugger" }
+
+[target.'cfg(target_os = "linux")'.dependencies]
+pete = "0.9"
+# For procfs, opt out of the `chrono` freature; it pulls in an old version
+# of `time`. We do not use the methods that the `chrono` feature enables.
+procfs = { version = "0.12", default-features = false, features=["flate2"] }
+
+[dev-dependencies]
+clap = { version = "4.0", features = ["derive"] }

src/agent/coverage/examples/coverage.rs

@@ -0,0 +1,65 @@
+use std::process::Command;
+use std::time::Duration;
+
+use anyhow::Result;
+use clap::Parser;
+use coverage::allowlist::{AllowList, TargetAllowList};
+use coverage::binary::BinaryCoverage;
+
+#[derive(Parser, Debug)]
+struct Args {
+    #[arg(long)]
+    module_allowlist: Option<String>,
+
+    #[arg(long)]
+    source_allowlist: Option<String>,
+
+    #[arg(short, long)]
+    timeout: Option<u64>,
+
+    command: Vec<String>,
+}
+
+const DEFAULT_TIMEOUT: Duration = Duration::from_secs(5);
+
+fn main() -> Result<()> {
+    let args = Args::parse();
+
+    let timeout = args
+        .timeout
+        .map(Duration::from_millis)
+        .unwrap_or(DEFAULT_TIMEOUT);
+
+    let mut cmd = Command::new(&args.command[0]);
+    if args.command.len() > 1 {
+        cmd.args(&args.command[1..]);
+    }
+
+    let mut allowlist = TargetAllowList::default();
+
+    if let Some(path) = &args.module_allowlist {
+        allowlist.modules = AllowList::load(path)?;
+    }
+
+    if let Some(path) = &args.source_allowlist {
+        allowlist.source_files = AllowList::load(path)?;
+    }
+
+    let coverage = coverage::record::record(cmd, timeout, allowlist)?;
+
+    dump_modoff(coverage)?;
+
+    Ok(())
+}
+
+fn dump_modoff(coverage: BinaryCoverage) -> Result<()> {
+    for (module, coverage) in &coverage.modules {
+        for (offset, count) in coverage.as_ref() {
+            if count.reached() {
+                println!("{}+{offset:x}", module.base_name());
+            }
+        }
+    }
+
+    Ok(())
+}

src/agent/coverage/src/allowlist.rs

@@ -0,0 +1,156 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+use anyhow::Result;
+use regex::{Regex, RegexSet};
+use std::path::Path;
+
+#[derive(Clone, Debug, Default)]
+pub struct TargetAllowList {
+    pub functions: AllowList,
+    pub modules: AllowList,
+    pub source_files: AllowList,
+}
+
+impl TargetAllowList {
+    pub fn new(modules: AllowList, source_files: AllowList) -> Self {
+        // Allow all.
+        let functions = AllowList::default();
+
+        Self {
+            functions,
+            modules,
+            source_files,
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct AllowList {
+    allow: RegexSet,
+    deny: RegexSet,
+}
+
+impl AllowList {
+    pub fn new(allow: RegexSet, deny: RegexSet) -> Self {
+        Self { allow, deny }
+    }
+
+    pub fn load(path: impl AsRef<Path>) -> Result<Self> {
+        let path = path.as_ref();
+        let text = std::fs::read_to_string(path)?;
+        Self::parse(&text)
+    }
+
+    pub fn parse(text: &str) -> Result<Self> {
+        use std::io::{BufRead, BufReader};
+
+        let reader = BufReader::new(text.as_bytes());
+
+        let mut allow = vec![];
+        let mut deny = vec![];
+
+        // We could just collect and pass to the `RegexSet` ctor.
+        //
+        // Instead, check each rule individually for diagnostic purposes.
+        for (index, line) in reader.lines().enumerate() {
+            let line = line?;
+
+            match AllowListLine::parse(&line) {
+                Ok(valid) => {
+                    use AllowListLine::*;
+
+                    match valid {
+                        Blank | Comment => {
+                            // Ignore.
+                        }
+                        Allow(re) => {
+                            allow.push(re);
+                        }
+                        Deny(re) => {
+                            deny.push(re);
+                        }
+                    }
+                }
+                Err(err) => {
+                    // Ignore invalid lines, but warn.
+                    let line_number = index + 1;
+                    warn!("error at line {}: {}", line_number, err);
+                }
+            }
+        }
+
+        let allow = RegexSet::new(allow.iter().map(|re| re.as_str()))?;
+        let deny = RegexSet::new(deny.iter().map(|re| re.as_str()))?;
+        let allowlist = AllowList::new(allow, deny);
+
+        Ok(allowlist)
+    }
+
+    pub fn is_allowed(&self, path: impl AsRef<str>) -> bool {
+        let path = path.as_ref();
+
+        // Allowed if rule-allowed but not excluded by a negative (deny) rule.
+        self.allow.is_match(path) && !self.deny.is_match(path)
+    }
+}
+
+impl Default for AllowList {
+    fn default() -> Self {
+        // Unwrap-safe due to valid constant expr.
+        let allow = RegexSet::new([".*"]).unwrap();
+        let deny = RegexSet::empty();
+
+        AllowList::new(allow, deny)
+    }
+}
+
+pub enum AllowListLine {
+    Blank,
+    Comment,
+    Allow(Regex),
+    Deny(Regex),
+}
+
+impl AllowListLine {
+    pub fn parse(line: &str) -> Result<Self> {
+        let line = line.trim();
+
+        // Allow and ignore blank lines.
+        if line.is_empty() {
+            return Ok(Self::Blank);
+        }
+
+        // Support comments of the form `# <comment>`.
+        if line.starts_with("# ") {
+            return Ok(Self::Comment);
+        }
+
+        // Deny rules are of the form `! <rule>`.
+        if let Some(expr) = line.strip_prefix("! ") {
+            let re = glob_to_regex(expr)?;
+            return Ok(Self::Deny(re));
+        }
+
+        // Try to interpret as allow rule.
+        let re = glob_to_regex(line)?;
+        Ok(Self::Allow(re))
+    }
+}
+
+#[allow(clippy::single_char_pattern)]
+fn glob_to_regex(expr: &str) -> Result<Regex> {
+    // Don't make users escape Windows path separators.
+    let expr = expr.replace(r"\", r"\\");
+
+    // Translate glob wildcards into quantified regexes.
+    let expr = expr.replace("*", ".*");
+
+    // Anchor to line start and end.
+    let expr = format!("^{expr}$");
+
+    Ok(Regex::new(&expr)?)
+}
+
+#[cfg(test)]
+mod tests;

src/agent/coverage/src/allowlist/test-data/allow-all-glob-except-commented.txt

@@ -0,0 +1,3 @@
+a/*
+! a/c
+# c

src/agent/coverage/src/allowlist/test-data/allow-all-glob-except.txt

@@ -0,0 +1,3 @@
+a/*
+! a/c
+c

src/agent/coverage/src/allowlist/test-data/allow-all-glob.txt

@@ -0,0 +1 @@
+*

src/agent/coverage/src/allowlist/test-data/allow-all.txt

@@ -0,0 +1,4 @@
+a
+a/b
+b
+c

src/agent/coverage/src/allowlist/test-data/allow-some.txt

@@ -0,0 +1,2 @@
+a
+b