1 files changed, 69 insertions, 0 deletions
diff --git a/shared/debug.go b/shared/debug.go
new file mode 100644
index 000000000..5392f2b79
--- /dev/null
+++ b/shared/debug.go
@@ -0,0 +1,69 @@
+package shared
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"syscall"
+)
+
+var (
+	isDebugging bool
+)
+
+// Finds the Delve binary to use. Either uses the SOONG_DELVE_PATH environment
+// variable or if that is unset, looks at $PATH.
+func ResolveDelveBinary() string {
+	result := os.Getenv("SOONG_DELVE_PATH")
+	if result == "" {
+		result, _ = exec.LookPath("dlv")
+	}
+
+	return result
+}
+
+// Returns whether the current process is running under Delve due to
+// ReexecWithDelveMaybe().
+func IsDebugging() bool {
+	return isDebugging
+}
+
+// Re-executes the binary in question under the control of Delve when
+// delveListen is not the empty string. delvePath gives the path to the Delve.
+func ReexecWithDelveMaybe(delveListen, delvePath string) {
+	isDebugging = os.Getenv("SOONG_DELVE_REEXECUTED") == "true"
+	if isDebugging || delveListen == "" {
+		return
+	}
+
+	if delvePath == "" {
+		fmt.Fprintln(os.Stderr, "Delve debugging requested but failed to find dlv")
+		os.Exit(1)
+	}
+
+	soongDelveEnv := []string{}
+	for _, env := range os.Environ() {
+		idx := strings.IndexRune(env, '=')
+		if idx != -1 {
+			soongDelveEnv = append(soongDelveEnv, env)
+		}
+	}
+
+	soongDelveEnv = append(soongDelveEnv, "SOONG_DELVE_REEXECUTED=true")
+
+	dlvArgv := []string{
+		delvePath,
+		"--listen=:" + delveListen,
+		"--headless=true",
+		"--api-version=2",
+		"exec",
+		os.Args[0],
+		"--",
+	}
+
+	dlvArgv = append(dlvArgv, os.Args[1:]...)
+	syscall.Exec(delvePath, dlvArgv, soongDelveEnv)
+	fmt.Fprintln(os.Stderr, "exec() failed while trying to reexec with Delve")
+	os.Exit(1)
+}