diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index 7fe2e6257d9e..7691f5c32b21 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -9,7 +9,7 @@ use std::str::FromStr;
 
 use crate::util::{add_dylib_path, PathBufExt};
 use lazycell::LazyCell;
-use test::ColorConfig;
+use test::{ColorConfig, OutputFormat};
 
 #[derive(Clone, Copy, PartialEq, Debug)]
 pub enum Mode {
@@ -337,7 +337,7 @@ pub struct Config {
     pub verbose: bool,
 
     /// Print one character per test instead of one line
-    pub quiet: bool,
+    pub format: OutputFormat,
 
     /// Whether to use colors in test.
     pub color: ColorConfig,
diff --git a/src/tools/compiletest/src/main.rs b/src/tools/compiletest/src/main.rs
index 1760c29ec66b..167cd5c5dc17 100644
--- a/src/tools/compiletest/src/main.rs
+++ b/src/tools/compiletest/src/main.rs
@@ -114,6 +114,7 @@ pub fn parse_config(args: Vec<String>) -> Config {
         )
         .optflag("", "quiet", "print one character per test instead of one line")
         .optopt("", "color", "coloring: auto, always, never", "WHEN")
+        .optflag("", "json", "emit json output instead of plaintext output")
         .optopt("", "logfile", "file to log test execution to", "FILE")
         .optopt("", "target", "the target to build for", "TARGET")
         .optopt("", "host", "the host to build for", "HOST")
@@ -281,7 +282,12 @@ pub fn parse_config(args: Vec<String>) -> Config {
             && !opt_str2(matches.opt_str("adb-test-dir")).is_empty(),
         lldb_python_dir: matches.opt_str("lldb-python-dir"),
         verbose: matches.opt_present("verbose"),
-        quiet: matches.opt_present("quiet"),
+        format: match (matches.opt_present("quiet"), matches.opt_present("json")) {
+            (true, true) => panic!("--quiet and --json are incompatible"),
+            (true, false) => test::OutputFormat::Terse,
+            (false, true) => test::OutputFormat::Json,
+            (false, false) => test::OutputFormat::Pretty,
+        },
         only_modified: matches.opt_present("only-modified"),
         color,
         remote_test_client: matches.opt_str("remote-test-client").map(PathBuf::from),
@@ -339,7 +345,7 @@ pub fn log_config(config: &Config) {
     logv(c, format!("ar: {}", config.ar));
     logv(c, format!("linker: {:?}", config.linker));
     logv(c, format!("verbose: {}", config.verbose));
-    logv(c, format!("quiet: {}", config.quiet));
+    logv(c, format!("format: {:?}", config.format));
     logv(c, "\n".to_string());
 }
 
@@ -501,7 +507,7 @@ pub fn test_opts(config: &Config) -> test::TestOpts {
         filters: config.filters.clone(),
         filter_exact: config.filter_exact,
         run_ignored: if config.run_ignored { test::RunIgnored::Yes } else { test::RunIgnored::No },
-        format: if config.quiet { test::OutputFormat::Terse } else { test::OutputFormat::Pretty },
+        format: config.format,
         logfile: config.logfile.clone(),
         run_tests: true,
         bench_benchmarks: true,