Rollup merge of #80408 - bjorn3:sync_cg_clif-2020-12-27, r=bjorn3

Sync rustc_codegen_cranelift

The highlight of this sync are two JIT mode improvements. The first is that it is now possible to use JIT mode when using `-Zcodegen-backend` instead of the custom driver using `-Cllvm-args=mode=jit`. The second one is a new JIT mode that lazily compiles functions when they are called the first time: https://github.com/bjorn3/rustc_codegen_cranelift/pull/1120

In addition this includes a few small runtime performance improvements and various fixes for rustc changes that didn't cause compilation to fail.

r? ``@ghost``

``@rustbot`` label +A-codegen +A-cranelift +T-compiler

Author: Dylan-DPC

compiler/rustc_codegen_cranelift/.vscode/settings.json

@@ -1,6 +1,7 @@
 {
     // source for rustc_* is not included in the rust-src component; disable the errors about this
     "rust-analyzer.diagnostics.disabled": ["unresolved-extern-crate"],
+    "rust-analyzer.assist.importMergeBehaviour": "last",
     "rust-analyzer.cargo.loadOutDirsFromCheck": true,
     "rust-analyzer.linkedProjects": [
         "./Cargo.toml",

compiler/rustc_codegen_cranelift/Cargo.lock

@@ -50,15 +50,15 @@ checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 [[package]]
 name = "cranelift-bforest"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 dependencies = [
  "cranelift-entity",
 ]
 
 [[package]]
 name = "cranelift-codegen"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 dependencies = [
  "byteorder",
  "cranelift-bforest",
@@ -76,7 +76,7 @@ dependencies = [
 [[package]]
 name = "cranelift-codegen-meta"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 dependencies = [
  "cranelift-codegen-shared",
  "cranelift-entity",
@@ -85,28 +85,46 @@ dependencies = [
 [[package]]
 name = "cranelift-codegen-shared"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 
 [[package]]
 name = "cranelift-entity"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 
 [[package]]
 name = "cranelift-frontend"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 dependencies = [
  "cranelift-codegen",
  "log",
  "smallvec",
  "target-lexicon",
 ]
 
+[[package]]
+name = "cranelift-jit"
+version = "0.68.0"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
+dependencies = [
+ "anyhow",
+ "cranelift-codegen",
+ "cranelift-entity",
+ "cranelift-module",
+ "cranelift-native",
+ "errno",
+ "libc",
+ "log",
+ "region",
+ "target-lexicon",
+ "winapi",
+]
+
 [[package]]
 name = "cranelift-module"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 dependencies = [
  "anyhow",
  "cranelift-codegen",
@@ -118,7 +136,7 @@ dependencies = [
 [[package]]
 name = "cranelift-native"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 dependencies = [
  "cranelift-codegen",
  "raw-cpuid",
@@ -128,7 +146,7 @@ dependencies = [
 [[package]]
 name = "cranelift-object"
 version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
+source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#8f7f8ee0b4c5007ace6de29b45505c360450b1bb"
 dependencies = [
  "anyhow",
  "cranelift-codegen",
@@ -138,23 +156,6 @@ dependencies = [
  "target-lexicon",
 ]
 
-[[package]]
-name = "cranelift-simplejit"
-version = "0.68.0"
-source = "git+https://github.com/bytecodealliance/wasmtime/?branch=main#19640367dbf0da7093e61add3306c8d092644fb3"
-dependencies = [
- "cranelift-codegen",
- "cranelift-entity",
- "cranelift-module",
- "cranelift-native",
- "errno",
- "libc",
- "log",
- "region",
- "target-lexicon",
- "winapi",
-]
-
 [[package]]
 name = "crc32fast"
 version = "1.2.1"
@@ -325,9 +326,9 @@ dependencies = [
  "ar",
  "cranelift-codegen",
  "cranelift-frontend",
+ "cranelift-jit",
  "cranelift-module",
  "cranelift-object",
- "cranelift-simplejit",
  "gimli",
  "indexmap",
  "libloading",

compiler/rustc_codegen_cranelift/Cargo.toml

@@ -12,7 +12,7 @@ crate-type = ["dylib"]
 cranelift-codegen = { git = "https://github.com/bytecodealliance/wasmtime/", branch = "main", features = ["unwind"] }
 cranelift-frontend = { git = "https://github.com/bytecodealliance/wasmtime/", branch = "main" }
 cranelift-module = { git = "https://github.com/bytecodealliance/wasmtime/", branch = "main" }
-cranelift-simplejit = { git = "https://github.com/bytecodealliance/wasmtime/", branch = "main", optional = true }
+cranelift-jit = { git = "https://github.com/bytecodealliance/wasmtime/", branch = "main", optional = true }
 cranelift-object = { git = "https://github.com/bytecodealliance/wasmtime/", branch = "main" }
 target-lexicon = "0.11.0"
 gimli = { version = "0.23.0", default-features = false, features = ["write"]}
@@ -27,15 +27,15 @@ libloading = { version = "0.6.0", optional = true }
 #cranelift-codegen = { path = "../wasmtime/cranelift/codegen" }
 #cranelift-frontend = { path = "../wasmtime/cranelift/frontend" }
 #cranelift-module = { path = "../wasmtime/cranelift/module" }
-#cranelift-simplejit = { path = "../wasmtime/cranelift/simplejit" }
+#cranelift-jit = { path = "../wasmtime/cranelift/jit" }
 #cranelift-object = { path = "../wasmtime/cranelift/object" }
 
 #[patch.crates-io]
 #gimli = { path = "../" }
 
 [features]
 default = ["jit", "inline_asm"]
-jit = ["cranelift-simplejit", "libloading"]
+jit = ["cranelift-jit", "libloading"]
 inline_asm = []
 
 [profile.dev]

compiler/rustc_codegen_cranelift/Readme.md

@@ -2,7 +2,7 @@
 
 > ⚠⚠⚠ Certain kinds of FFI don't work yet. ⚠⚠⚠
 
-The goal of this project is to create an alternative codegen backend for the rust compiler based on [Cranelift](https://github.com/bytecodealliance/wasmtime/blob/master/cranelift).
+The goal of this project is to create an alternative codegen backend for the rust compiler based on [Cranelift](https://github.com/bytecodealliance/wasmtime/blob/main/cranelift).
 This has the potential to improve compilation times in debug mode.
 If your project doesn't use any of the things listed under "Not yet supported", it should work fine.
 If not please open an issue.
@@ -68,7 +68,15 @@ $ $cg_clif_dir/build/cargo.sh jit
 or
 
 ```bash
-$ $cg_clif_dir/build/bin/cg_clif --jit my_crate.rs
+$ $cg_clif_dir/build/bin/cg_clif -Cllvm-args=mode=jit -Cprefer-dynamic my_crate.rs
+```
+
+There is also an experimental lazy jit mode. In this mode functions are only compiled once they are
+first called. It currently does not work with multi-threaded programs. When a not yet compiled
+function is called from another thread than the main thread, you will get an ICE.
+
+```bash
+$ $cg_clif_dir/build/cargo.sh lazy-jit
 ```
 
 ### Shell
@@ -77,7 +85,7 @@ These are a few functions that allow you to easily run rust code from the shell
 
 ```bash
 function jit_naked() {
-    echo "$@" | $cg_clif_dir/build/bin/cg_clif - --jit
+    echo "$@" | $cg_clif_dir/build/bin/cg_clif - -Cllvm-args=mode=jit -Cprefer-dynamic
 }
 
 function jit() {

compiler/rustc_codegen_cranelift/build_sysroot/Cargo.lock

@@ -47,9 +47,9 @@ checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
 [[package]]
 name = "cc"
-version = "1.0.65"
+version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "95752358c8f7552394baf48cd82695b345628ad3f170d607de3ca03b8dacca15"
+checksum = "4c0496836a84f8d0495758516b8621a622beb77c0fed418570e50764093ced48"
 
 [[package]]
 name = "cfg-if"
@@ -141,9 +141,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.80"
+version = "0.2.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4d58d1b70b004888f764dfbf6a26a3b0342a1632d33968e4a179d8011c760614"
+checksum = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
 dependencies = [
  "rustc-std-workspace-core",
 ]

compiler/rustc_codegen_cranelift/build_sysroot/Cargo.toml

@@ -5,13 +5,14 @@ version = "0.0.0"
 
 [dependencies]
 core = { path = "./sysroot_src/library/core" }
-compiler_builtins = "0.1"
 alloc = { path = "./sysroot_src/library/alloc" }
 std = { path = "./sysroot_src/library/std", features = ["panic_unwind", "backtrace"] }
 test = { path = "./sysroot_src/library/test" }
 
 alloc_system = { path = "./alloc_system" }
 
+compiler_builtins = { version = "=0.1.36", default-features = false }
+
 [patch.crates-io]
 rustc-std-workspace-core = { path = "./sysroot_src/library/rustc-std-workspace-core" }
 rustc-std-workspace-alloc = { path = "./sysroot_src/library/rustc-std-workspace-alloc" }

compiler/rustc_codegen_cranelift/example/std_example.rs

@@ -15,6 +15,8 @@ fn main() {
     let stderr = ::std::io::stderr();
     let mut stderr = stderr.lock();
 
+    // FIXME support lazy jit when multi threading
+    #[cfg(not(lazy_jit))]
     std::thread::spawn(move || {
         println!("Hello from another thread!");
     });

compiler/rustc_codegen_cranelift/rust-toolchain

@@ -1 +1 @@
-nightly-2020-11-27
+nightly-2020-12-23

compiler/rustc_codegen_cranelift/scripts/cargo.sh

@@ -10,7 +10,9 @@ cmd=$1
 shift || true
 
 if [[ "$cmd" = "jit" ]]; then
-cargo "+${TOOLCHAIN}" rustc "$@" -- --jit
+cargo "+${TOOLCHAIN}" rustc "$@" -- -Cllvm-args=mode=jit -Cprefer-dynamic
+elif [[ "$cmd" = "lazy-jit" ]]; then
+cargo "+${TOOLCHAIN}" rustc "$@" -- -Cllvm-args=mode=jit-lazy -Cprefer-dynamic
 else
 cargo "+${TOOLCHAIN}" "$cmd" "$@"
 fi

compiler/rustc_codegen_cranelift/scripts/filter_profile.rs

@@ -4,7 +4,7 @@
 pushd $(dirname "$0")/../
 source build/config.sh
 popd
-PROFILE=$1 OUTPUT=$2 exec $RUSTC $RUSTFLAGS --jit $0
+PROFILE=$1 OUTPUT=$2 exec $RUSTC $RUSTFLAGS -Cllvm-args=mode=jit -Cprefer-dynamic $0
 #*/
 
 //! This program filters away uninteresting samples and trims uninteresting frames for stackcollapse

compiler/rustc_codegen_cranelift/scripts/tests.sh

@@ -15,7 +15,10 @@ function no_sysroot_tests() {
 
     if [[ "$JIT_SUPPORTED" = "1" ]]; then
         echo "[JIT] mini_core_hello_world"
-        CG_CLIF_JIT_ARGS="abc bcd" $MY_RUSTC --jit example/mini_core_hello_world.rs --cfg jit --target "$HOST_TRIPLE"
+        CG_CLIF_JIT_ARGS="abc bcd" $MY_RUSTC -Cllvm-args=mode=jit -Cprefer-dynamic example/mini_core_hello_world.rs --cfg jit --target "$HOST_TRIPLE"
+
+        echo "[JIT-lazy] mini_core_hello_world"
+        CG_CLIF_JIT_ARGS="abc bcd" $MY_RUSTC -Cllvm-args=mode=jit-lazy -Cprefer-dynamic example/mini_core_hello_world.rs --cfg jit --target "$HOST_TRIPLE"
     else
         echo "[JIT] mini_core_hello_world (skipped)"
     fi
@@ -37,7 +40,10 @@ function base_sysroot_tests() {
 
     if [[ "$JIT_SUPPORTED" = "1" ]]; then
         echo "[JIT] std_example"
-        $MY_RUSTC --jit example/std_example.rs --target "$HOST_TRIPLE"
+        $MY_RUSTC -Cllvm-args=mode=jit -Cprefer-dynamic example/std_example.rs --target "$HOST_TRIPLE"
+
+        echo "[JIT-lazy] std_example"
+        $MY_RUSTC -Cllvm-args=mode=jit-lazy -Cprefer-dynamic example/std_example.rs --cfg lazy_jit --target "$HOST_TRIPLE"
     else
         echo "[JIT] std_example (skipped)"
     fi

compiler/rustc_codegen_cranelift/src/backend.rs

@@ -162,7 +162,7 @@ impl AddConstructor for ObjectProduct {
 }
 
 pub(crate) fn with_object(sess: &Session, name: &str, f: impl FnOnce(&mut Object)) -> Vec<u8> {
-    let triple = crate::build_isa(sess, true).triple().clone();
+    let triple = crate::build_isa(sess).triple().clone();
 
     let binary_format = match triple.binary_format {
         target_lexicon::BinaryFormat::Elf => object::BinaryFormat::Elf,
@@ -193,7 +193,7 @@ pub(crate) fn with_object(sess: &Session, name: &str, f: impl FnOnce(&mut Object
 
 pub(crate) fn make_module(sess: &Session, name: String) -> ObjectModule {
     let mut builder = ObjectBuilder::new(
-        crate::build_isa(sess, true),
+        crate::build_isa(sess),
         name + ".o",
         cranelift_module::default_libcall_names(),
     )

compiler/rustc_codegen_cranelift/src/base.rs

@@ -118,6 +118,8 @@ pub(crate) fn codegen_fn<'tcx>(
     context.eliminate_unreachable_code(cx.module.isa()).unwrap();
     context.dce(cx.module.isa()).unwrap();
 
+    context.want_disasm = crate::pretty_clif::should_write_ir(tcx);
+
     // Define function
     let module = &mut cx.module;
     tcx.sess.time("define function", || {
@@ -140,6 +142,16 @@ pub(crate) fn codegen_fn<'tcx>(
         &clif_comments,
     );
 
+    if let Some(mach_compile_result) = &context.mach_compile_result {
+        if let Some(disasm) = &mach_compile_result.disasm {
+            crate::pretty_clif::write_ir_file(
+                tcx,
+                &format!("{}.vcode", tcx.symbol_name(instance).name),
+                |file| file.write_all(disasm.as_bytes()),
+            )
+        }
+    }
+
     // Define debuginfo for function
     let isa = cx.module.isa();
     let debug_context = &mut cx.debug_context;
@@ -307,7 +319,9 @@ fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, impl Module>) {
             } => {
                 let discr = codegen_operand(fx, discr).load_scalar(fx);
 
-                if switch_ty.kind() == fx.tcx.types.bool.kind() {
+                let use_bool_opt = switch_ty.kind() == fx.tcx.types.bool.kind()
+                    || (targets.iter().count() == 1 && targets.iter().next().unwrap().0 == 0);
+                if use_bool_opt {
                     assert_eq!(targets.iter().count(), 1);
                     let (then_value, then_block) = targets.iter().next().unwrap();
                     let then_block = fx.get_block(then_block);
@@ -325,12 +339,22 @@ fn codegen_fn_content(fx: &mut FunctionCx<'_, '_, impl Module>) {
                     let discr = crate::optimize::peephole::maybe_unwrap_bint(&mut fx.bcx, discr);
                     let discr =
                         crate::optimize::peephole::make_branchable_value(&mut fx.bcx, discr);
-                    if test_zero {
-                        fx.bcx.ins().brz(discr, then_block, &[]);
-                        fx.bcx.ins().jump(else_block, &[]);
+                    if let Some(taken) = crate::optimize::peephole::maybe_known_branch_taken(
+                        &fx.bcx, discr, test_zero,
+                    ) {
+                        if taken {
+                            fx.bcx.ins().jump(then_block, &[]);
+                        } else {
+                            fx.bcx.ins().jump(else_block, &[]);
+                        }
                     } else {
-                        fx.bcx.ins().brnz(discr, then_block, &[]);
-                        fx.bcx.ins().jump(else_block, &[]);
+                        if test_zero {
+                            fx.bcx.ins().brz(discr, then_block, &[]);
+                            fx.bcx.ins().jump(else_block, &[]);
+                        } else {
+                            fx.bcx.ins().brnz(discr, then_block, &[]);
+                            fx.bcx.ins().jump(else_block, &[]);
+                        }
                     }
                 } else {
                     let mut switch = ::cranelift_frontend::Switch::new();