Remove the LLVM/bindgen/cmake dependencies from wasmtime-runtime

.azure-pipelines.yml

@@ -63,12 +63,6 @@ jobs:
       submodules: true
     - template: ci/azure-install-rust.yml
 
-    - script: |
-        powershell -Command "$ProgressPreference = 'SilentlyContinue'; iwr -outf %TEMP%\LLVM-8.0.0-win64.exe https://rust-lang-ci2.s3.amazonaws.com/rust-ci-mirror/LLVM-8.0.0-win64.exe"
-        %TEMP%\LLVM-8.0.0-win64.exe /S /NCRC
-      condition: eq(variables['Agent.OS'], 'Windows_NT')
-      displayName: Install clang (Windows)
-
     - script: cargo fetch
       displayName: Fetch cargo dependencies
 
@@ -118,12 +112,6 @@ jobs:
     - bash: echo "##vso[task.setvariable variable=RUSTC_VERSION;]`rustc --version`"
       displayName: Set rustc version string for caching
 
-    - script: |
-        powershell -Command "$ProgressPreference = 'SilentlyContinue'; iwr -outf %TEMP%\LLVM-8.0.0-win64.exe https://rust-lang-ci2.s3.amazonaws.com/rust-ci-mirror/LLVM-8.0.0-win64.exe"
-        %TEMP%\LLVM-8.0.0-win64.exe /S /NCRC
-      condition: eq(variables['Agent.OS'], 'Windows_NT')
-      displayName: Install clang (Windows)
-
     # - bash: |
     #     set -e
     #     curl -Lfo sccache.tar.gz https://github.com/mozilla/sccache/releases/download/0.2.9/sccache-0.2.9-x86_64-apple-darwin.tar.gz

README.md

@@ -22,9 +22,11 @@ obtain a full checkout, like this:
 git clone --recurse-submodules https://github.com/CraneStation/wasmtime.git
 ```
 
-To build Wasmtime, install cmake and clang, and then build with cargo, such
-as with "cargo build --release". For information on installing clang, see
-[rust-bindgen's documentation](https://github.com/rust-lang/rust-bindgen/blob/master/book/src/requirements.md).
+To build an optimized version of Wasmtime, use Cargo:
+
+```
+cargo build --release
+```
 
 There are Rust, C, and C++ toolchains that can compile programs with WASI. See
 the [WASI intro][WASI intro] for more information, and the [WASI tutorial][WASI tutorial]

wasmtime-runtime/Cargo.toml

@@ -29,9 +29,7 @@ indexmap = "1.0.2"
 winapi = { version = "0.3.6", features = ["winbase", "memoryapi"] }
 
 [build-dependencies]
-cmake = "0.1.35"
-bindgen = "0.51.0"
-regex = "1.0.6"
+cc = "1.0"
 
 [features]
 default = ["std"]

wasmtime-runtime/build.rs

@@ -1,37 +1,20 @@
-extern crate bindgen;
-extern crate cmake;
-extern crate regex;
-
-use cmake::Config;
-use regex::Regex;
-use std::env;
-use std::path::PathBuf;
-
 fn main() {
-    let dst = Config::new("signalhandlers").build();
-
-    println!("cargo:rustc-link-search=native={}", dst.display());
-    println!("cargo:rustc-link-lib=static=SignalHandlers");
-
-    let mut bindings_builder = bindgen::Builder::default()
-        .header("signalhandlers/SignalHandlers.hpp")
-        .whitelist_type("TrapContext")
-        .whitelist_type("jmp_buf")
-        .whitelist_function("EnsureEagerSignalHandlers");
-
-    // If we're compiling for Darwin, compile in extra Darwin support routines.
-    if Regex::new(r"-darwin[[:digit:].]*$")
-        .unwrap()
-        .is_match(&env::var("TARGET").unwrap())
-    {
-        bindings_builder = bindings_builder.whitelist_function("EnsureDarwinMachPorts");
+    println!("cargo:rerun-if-changed=signalhandlers/SignalHandlers.cpp");
+    println!("cargo:rerun-if-changed=signalhandlers/SignalHandlers.hpp");
+    println!("cargo:rerun-if-changed=signalhandlers/Trampolines.cpp");
+    let target = std::env::var("TARGET").unwrap();
+    let mut build = cc::Build::new();
+    build
+        .cpp(true)
+        .warnings(false)
+        .file("signalhandlers/SignalHandlers.cpp")
+        .file("signalhandlers/Trampolines.cpp");
+    if !target.contains("windows") {
+        build
+            .flag("-std=c++11")
+            .flag("-fno-exceptions")
+            .flag("-fno-rtti");
     }
 
-    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
-
-    bindings_builder
-        .generate()
-        .expect("Unable to generate bindings")
-        .write_to_file(out_path.join("signalhandlers.rs"))
-        .expect("Couldn't write bindings!");
+    build.compile("signalhandlers");
 }

wasmtime-runtime/signalhandlers/SignalHandlers.cpp

@@ -668,7 +668,7 @@ WasmTrapHandler(int signum, siginfo_t* info, void* context)
 extern "C" MFBT_API bool IsSignalHandlingBroken();
 #endif
 
-bool
+int
 EnsureEagerSignalHandlers()
 {
 #if defined(ANDROID) && defined(MOZ_LINKER)
@@ -765,7 +765,7 @@ EnsureEagerSignalHandlers()
     return true;
 }
 
-bool
+int
 EnsureDarwinMachPorts()
 {
 #ifdef USE_APPLE_MACH_PORTS

wasmtime-runtime/signalhandlers/SignalHandlers.hpp

@@ -14,15 +14,11 @@ extern "C" {
 // Record the Trap code and wasm bytecode offset in TLS somewhere
 void RecordTrap(const uint8_t* pc);
 
-// Initiate an unwind.
+void* EnterScope(void*);
+void LeaveScope(void*);
+void* GetScope(void);
 void Unwind(void);
 
-// Trap initialization state.
-struct TrapContext {
-    bool triedToInstallSignalHandlers;
-    bool haveSignalHandlers;
-};
-
 // This function performs the low-overhead signal handler initialization that we
 // want to do eagerly to ensure a more-deterministic global process state. This
 // is especially relevant for signal handlers since handler ordering depends on
@@ -31,14 +27,14 @@ struct TrapContext {
 // called at the end of the startup process, after other handlers have been
 // installed. This function can thus be called multiple times, having no effect
 // after the first call.
-bool
+int
 EnsureEagerSignalHandlers(void);
 
 // Assuming EnsureEagerProcessSignalHandlers() has already been called,
 // this function performs the full installation of signal handlers which must
 // be performed per-thread. This operation may incur some overhead and
 // so should be done only when needed to use wasm.
-bool
+int
 EnsureDarwinMachPorts(void);
 
 #ifdef __cplusplus

wasmtime-runtime/signalhandlers/Trampolines.cpp

@@ -0,0 +1,37 @@
+#include <setjmp.h>
+
+#include "SignalHandlers.hpp"
+
+extern "C"
+int WasmtimeCallTrampoline(void *vmctx, void (*body)(void*, void*), void *args) {
+  jmp_buf buf;
+  void *volatile prev;
+  if (setjmp(buf) != 0) {
+    LeaveScope(prev);
+    return 0;
+  }
+  prev = EnterScope(&buf);
+  body(vmctx, args);
+  LeaveScope(prev);
+  return 1;
+}
+
+extern "C"
+int WasmtimeCall(void *vmctx, void (*body)(void*)) {
+  jmp_buf buf;
+  void *volatile prev;
+  if (setjmp(buf) != 0) {
+    LeaveScope(prev);
+    return 0;
+  }
+  prev = EnterScope(&buf);
+  body(vmctx);
+  LeaveScope(prev);
+  return 1;
+}
+
+extern "C"
+void Unwind() {
+  jmp_buf *buf = (jmp_buf*) GetScope();
+  longjmp(*buf, 1);
+}

wasmtime-runtime/src/signalhandlers.rs

@@ -6,10 +6,20 @@
 
 use crate::vmcontext::VMContext;
 use core::borrow::{Borrow, BorrowMut};
-use core::cell::RefCell;
+use core::cell::Cell;
 use std::sync::RwLock;
 
-include!(concat!(env!("OUT_DIR"), "/signalhandlers.rs"));
+#[derive(Default)]
+struct TrapContext {
+    tried_to_install_signal_handlers: Cell<bool>,
+    have_signal_handlers: Cell<bool>,
+}
+
+extern "C" {
+    fn EnsureEagerSignalHandlers() -> libc::c_int;
+    #[cfg(any(target_os = "macos", target_os = "ios"))]
+    fn EnsureDarwinMachPorts() -> libc::c_int;
+}
 
 struct InstallState {
     tried: bool,
@@ -50,16 +60,15 @@ pub extern "C" fn wasmtime_init_eager() {
     state.tried = true;
     assert!(!state.success);
 
-    if !unsafe { EnsureEagerSignalHandlers() } {
+    if unsafe { EnsureEagerSignalHandlers() == 0 } {
         return;
     }
 
     state.success = true;
 }
 
 thread_local! {
-    static TRAP_CONTEXT: RefCell<TrapContext> =
-        RefCell::new(TrapContext { triedToInstallSignalHandlers: false, haveSignalHandlers: false });
+    static TRAP_CONTEXT: TrapContext = TrapContext::default();
 }
 
 /// Assuming `EnsureEagerProcessSignalHandlers` has already been called,
@@ -68,10 +77,10 @@ thread_local! {
 /// so should be done only when needed to use wasm.
 #[no_mangle]
 pub extern "C" fn wasmtime_init_finish(vmctx: &mut VMContext) {
-    if !TRAP_CONTEXT.with(|cx| cx.borrow().triedToInstallSignalHandlers) {
+    if !TRAP_CONTEXT.with(|cx| cx.tried_to_install_signal_handlers.get()) {
         TRAP_CONTEXT.with(|cx| {
-            cx.borrow_mut().triedToInstallSignalHandlers = true;
-            assert!(!cx.borrow().haveSignalHandlers);
+            cx.tried_to_install_signal_handlers.set(true);
+            assert!(!cx.have_signal_handlers.get());
         });
 
         {
@@ -90,12 +99,12 @@ pub extern "C" fn wasmtime_init_finish(vmctx: &mut VMContext) {
         ensure_darwin_mach_ports();
 
         TRAP_CONTEXT.with(|cx| {
-            cx.borrow_mut().haveSignalHandlers = true;
+            cx.have_signal_handlers.set(true);
         })
     }
 
     let instance = unsafe { vmctx.instance() };
-    let have_signal_handlers = TRAP_CONTEXT.with(|cx| cx.borrow().haveSignalHandlers);
+    let have_signal_handlers = TRAP_CONTEXT.with(|cx| cx.have_signal_handlers.get());
     if !have_signal_handlers && instance.needs_signal_handlers() {
         panic!("failed to install signal handlers");
     }
@@ -113,7 +122,7 @@ fn ensure_darwin_mach_ports() {
     state.tried = true;
     assert!(!state.success);
 
-    if !unsafe { EnsureDarwinMachPorts() } {
+    if unsafe { EnsureDarwinMachPorts() != 0 } {
         return;
     }