Enable jitdump profiling support by default (#1310)

* Enable jitdump profiling support by default

This the result of some of the investigation I was doing for #1017. I've
done a number of refactorings here which culminated in a number of
changes that all amount to what I think should result in jitdump support being
enabled by default:

* Pass in a list of finished functions instead of just a range to
  ensure that we're emitting jit dump data for a specific module rather
  than a whole `CodeMemory` which may have other modules.
* Define `ProfilingStrategy` in the `wasmtime` crate to have everything
  locally-defined
* Add support to the C API to enable profiling
* Documentation added for profiling with jitdump to the book
* Split out supported/unsupported files in `jitdump.rs` to avoid having
  lots of `#[cfg]`.
* Make dependencies optional that are only used for `jitdump`.
* Move initialization up-front to `JitDumpAgent::new()` instead of
  deferring it to the first module.
* Pass around `Arc<dyn ProfilingAgent>` instead of
  `Option<Arc<Mutex<Box<dyn ProfilingAgent>>>>`

The `jitdump` Cargo feature is now enabled by default which means that
our published binaries, C API artifacts, and crates will support
profiling at runtime by default. The support I don't think is fully
fleshed out and working but I think it's probably in a good enough spot
we can get users playing around with it!

tests/instantiate.rs

@@ -1,40 +0,0 @@
-use more_asserts::assert_gt;
-use std::path::PathBuf;
-use wasmtime_environ::settings;
-use wasmtime_environ::settings::Configurable;
-use wasmtime_environ::CacheConfig;
-use wasmtime_jit::{instantiate, native, CompilationStrategy, Compiler, NullResolver};
-
-const PATH_MODULE_RS2WASM_ADD_FUNC: &str = r"tests/wasm/rs2wasm-add-func.wat";
-
-/// Simple test reading a wasm-file and translating to binary representation.
-#[test]
-fn test_environ_translate() {
-    let path = PathBuf::from(PATH_MODULE_RS2WASM_ADD_FUNC);
-    let data = wat::parse_file(path).expect("expecting valid wat-file");
-    assert_gt!(data.len(), 0);
-
-    let mut flag_builder = settings::builder();
-    flag_builder.enable("enable_verifier").unwrap();
-
-    let isa_builder = native::builder();
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
-
-    let mut resolver = NullResolver {};
-    let cache_config = CacheConfig::new_cache_disabled();
-    let mut compiler = Compiler::new(isa, CompilationStrategy::Auto, cache_config);
-    unsafe {
-        let instance = instantiate(
-            &mut compiler,
-            &data,
-            &mut resolver,
-            // Bulk memory.
-            false,
-            // Debug info.
-            false,
-            // Profiler.
-            None,
-        );
-        assert!(instance.is_ok());
-    }
-}

tests/misc_testsuite/rs2wasm-add-func.wast

@@ -0,0 +1,20 @@
+(module
+  (type (;0;) (func))
+  (type (;1;) (func (param i32 i32) (result i32)))
+  (func $add (type 1) (param i32 i32) (result i32)
+    get_local 1
+    get_local 0
+    i32.add)
+  (func $start (type 0))
+  (table (;0;) 1 1 anyfunc)
+  (memory (;0;) 17)
+  (global (;0;) i32 (i32.const 1049114))
+  (global (;1;) i32 (i32.const 1049114))
+  (export "memory" (memory 0))
+  (export "__indirect_function_table" (table 0))
+  (export "__heap_base" (global 0))
+  (export "__data_end" (global 1))
+  (export "add" (func $add))
+  (export "start" (func $start))
+  (data (i32.const 1048576) "\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00")
+  (data (i32.const 1049092) "invalid malloc request"))