diff --git a/cranelift/src/libreader/lib.rs b/cranelift/src/libreader/lib.rs
index 519fee7eed..d435b4ac3b 100644
--- a/cranelift/src/libreader/lib.rs
+++ b/cranelift/src/libreader/lib.rs
@@ -5,9 +5,11 @@
 
 extern crate cretonne;
 
-pub use parser::{Result, parse_functions};
+pub use parser::{Result, parse_functions, parse_test};
 pub use testcommand::{TestCommand, TestOption};
+pub use testfile::TestFile;
 
 mod lexer;
 mod parser;
 mod testcommand;
+mod testfile;
diff --git a/cranelift/src/libreader/parser.rs b/cranelift/src/libreader/parser.rs
index 2ae1629c80..e9d77c67d7 100644
--- a/cranelift/src/libreader/parser.rs
+++ b/cranelift/src/libreader/parser.rs
@@ -18,6 +18,7 @@ use cretonne::ir::immediates::{Imm64, Ieee32, Ieee64};
 use cretonne::ir::entities::{NO_EBB, NO_VALUE};
 use cretonne::ir::instructions::{InstructionFormat, InstructionData, VariableArgs, JumpData,
                                  BranchData, ReturnData};
+use testfile::TestFile;
 
 pub use lexer::Location;
 
@@ -28,6 +29,14 @@ pub fn parse_functions(text: &str) -> Result<Vec<Function>> {
     Parser::new(text).parse_function_list()
 }
 
+/// Parse the entire `text` as a test case file.
+///
+/// The returned `TestFile` contains direct references to substrings of `text`.
+pub fn parse_test<'a>(text: &'a str) -> Result<TestFile<'a>> {
+    Parser::new(text);
+    unimplemented!()
+}
+
 /// A parse error is returned when the parse failed.
 #[derive(Debug)]
 pub struct Error {
diff --git a/cranelift/src/libreader/testfile.rs b/cranelift/src/libreader/testfile.rs
new file mode 100644
index 0000000000..34eddb4c6b
--- /dev/null
+++ b/cranelift/src/libreader/testfile.rs
@@ -0,0 +1,40 @@
+//! Data structures representing a parsed test file.
+//!
+//! A test file is a `.cton` file which contains test commands and settings for running a
+//! file-based test case.
+//!
+
+use cretonne::ir::Function;
+use cretonne::ir::entities::AnyEntity;
+use testcommand::TestCommand;
+
+/// A parsed test case.
+///
+/// This is the result of parsing a `.cton` file which contains a number of test commands followed
+/// by the functions that should be tested.
+#[derive(Debug)]
+pub struct TestFile<'a> {
+    pub commands: Vec<TestCommand<'a>>,
+    pub functions: Vec<DetailedFunction<'a>>,
+}
+
+/// A function parsed from a text string along with other details that are useful for running
+/// tests.
+#[derive(Debug)]
+pub struct DetailedFunction<'a> {
+    pub function: Function,
+    pub comments: Vec<Comment<'a>>,
+}
+
+/// A comment in a parsed function.
+///
+/// The comment belongs to the immediately preceeding entity, whether that is an EBB header, and
+/// instruction, or one of the preamble declarations.
+///
+/// Comments appearing inside the function but before the preamble, as well as comments appearing
+/// after the function are tagged as `AnyEntity::Function`.
+#[derive(Clone, PartialEq, Eq, Debug)]
+pub struct Comment<'a> {
+    pub entity: AnyEntity,
+    pub text: &'a str,
+}