Add options for parsing test files (#942)

* Add options for parsing test files

This change allows adding parsing parameters more easily; e.g. a parameter is needed for setting the default calling convention for functions parsed as a part of the `run` test feature.

* Set default calling convention that of the host for `test run` file tests

Previously `test run` used the parser's hard-coded CallConv::Fast as the default calling convention but with this change any test being `run` will use the default calling convention of the machine running the test. `test run` will now throw an error if the calling convention of the function does not match the host's.

cranelift/src/compile.rs

@@ -6,7 +6,7 @@ use cranelift_codegen::print_errors::pretty_error;
 use cranelift_codegen::settings::FlagsOrIsa;
 use cranelift_codegen::timing;
 use cranelift_codegen::Context;
-use cranelift_reader::parse_test;
+use cranelift_reader::{parse_test, ParseOptions};
 use std::path::Path;
 use std::path::PathBuf;
 
@@ -44,7 +44,8 @@ fn handle_module(
     fisa: FlagsOrIsa,
 ) -> Result<(), String> {
     let buffer = read_to_string(&path).map_err(|e| format!("{}: {}", name, e))?;
-    let test_file = parse_test(&buffer, None, None).map_err(|e| format!("{}: {}", name, e))?;
+    let test_file =
+        parse_test(&buffer, ParseOptions::default()).map_err(|e| format!("{}: {}", name, e))?;
 
     // If we have an isa from the command-line, use that. Otherwise if the
     // file contains a unique isa, use that.