cranelift: Add heap support to filetest infrastructure (#3154)

* cranelift: Add heap support to filetest infrastructure

* cranelift: Explicit heap pointer placement in filetest annotations

* cranelift: Add documentation about the Heap directive

* cranelift: Clarify that heap filetests pointers must be laid out sequentially

* cranelift: Use wrapping add when computing bound pointer

* cranelift: Better error messages when invalid signatures are found for heap file tests.

cranelift/filetests/src/test_run.rs

@@ -3,8 +3,10 @@
 //! The `run` test command compiles each function on the host machine and executes it
 
 use crate::function_runner::SingleFunctionCompiler;
+use crate::runtest_environment::RuntestEnvironment;
 use crate::subtest::{Context, SubTest};
 use cranelift_codegen::ir;
+use cranelift_codegen::ir::ArgumentPurpose;
 use cranelift_reader::parse_run_command;
 use cranelift_reader::TestCommand;
 use log::trace;
@@ -48,6 +50,8 @@ impl SubTest for TestRun {
         }
         let variant = context.isa.unwrap().variant();
 
+        let test_env = RuntestEnvironment::parse(&context.details.comments[..])?;
+
         let mut compiler = SingleFunctionCompiler::with_host_isa(context.flags.clone(), variant);
         for comment in context.details.comments.iter() {
             if let Some(command) = parse_run_command(comment.text, &func.signature)? {
@@ -60,7 +64,31 @@ impl SubTest for TestRun {
                 // running x86_64 code on aarch64 platforms.
                 let compiled_fn = compiler.compile(func.clone().into_owned())?;
                 command
-                    .run(|_, args| Ok(compiled_fn.call(args)))
+                    .run(|_, run_args| {
+                        let runtime_struct = test_env.runtime_struct();
+
+                        let first_arg_is_vmctx = func
+                            .signature
+                            .params
+                            .first()
+                            .map(|p| p.purpose == ArgumentPurpose::VMContext)
+                            .unwrap_or(false);
+
+                        if !first_arg_is_vmctx && test_env.is_active() {
+                            return Err(concat!(
+                                "This test requests a heap, but the first argument is not `i64 vmctx`.\n",
+                                "See docs/testing.md for more info on using heap annotations."
+                            ).to_string());
+                        }
+
+                        let mut args = Vec::with_capacity(run_args.len());
+                        if test_env.is_active() {
+                            args.push(runtime_struct.pointer(context.isa.unwrap().pointer_type()));
+                        }
+                        args.extend_from_slice(run_args);
+
+                        Ok(compiled_fn.call(&args))
+                    })
                     .map_err(|s| anyhow::anyhow!("{}", s))?;
             }
         }