feat: add Succinct target, impl stdlib functionality

Author: nhtyy

compiler/rustc_target/src/spec/mod.rs

@@ -1954,6 +1954,7 @@ supported_targets! {
 
     ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),
     ("riscv32im-risc0-zkvm-elf", riscv32im_risc0_zkvm_elf),
+    ("riscv32im-succinct-zkvm-elf", riscv32im_succinct_zkvm_elf),
     ("riscv32im-unknown-none-elf", riscv32im_unknown_none_elf),
     ("riscv32ima-unknown-none-elf", riscv32ima_unknown_none_elf),
     ("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),

compiler/rustc_target/src/spec/targets/riscv32im_succinct_zkvm_elf.rs

@@ -0,0 +1,42 @@
+use crate::spec::{
+    Cc, LinkerFlavor, Lld, PanicStrategy, RelocModel, Target, TargetMetadata, TargetOptions,
+};
+
+pub(crate) fn target() -> Target {
+    Target {
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S128".into(),
+        llvm_target: "riscv32".into(),
+        metadata: TargetMetadata {
+            description: Some("Succinct's zero-knowledge Virtual Machine (RV32IM ISA)".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(true),
+        },
+        pointer_width: 32,
+        arch: "riscv32".into(),
+
+        options: TargetOptions {
+            os: "succinct-zkvm".into(),
+            vendor: "succinct".into(),
+            linker_flavor: LinkerFlavor::Gnu(Cc::No, Lld::Yes),
+            linker: Some("rust-lld".into()),
+            cpu: "generic-rv32".into(),
+
+            // The zkvm is singlethreaded and all operations are atomic.
+            // The std-lib is compiled with lowered atomicsa and the default Succinct build tools
+            // enforce this on programs.
+            max_atomic_width: Some(64),
+            atomic_cas: true,
+
+            features: "+m".into(),
+            llvm_abiname: "ilp32".into(),
+            executables: true,
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: RelocModel::Static,
+            emit_debug_gdb_scripts: false,
+            eh_frame_header: false,
+            singlethread: true,
+            ..Default::default()
+        },
+    }
+}

library/panic_abort/Cargo.toml

@@ -19,3 +19,10 @@ compiler_builtins = "0.1.0"
 
 [target.'cfg(not(all(windows, target_env = "msvc")))'.dependencies]
 libc = { version = "0.2", default-features = false }
+
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = [
+    'cfg(bootstrap)',
+    'cfg(target_os, values("succinct-zkvm"))'
+]

library/panic_abort/src/lib.rs

@@ -20,7 +20,7 @@
 #[cfg(target_os = "android")]
 mod android;
 
-#[cfg(target_os = "zkvm")]
+#[cfg(any(target_os = "zkvm", target_os = "succinct-zkvm"))]
 mod zkvm;
 
 use core::any::Any;
@@ -40,7 +40,7 @@ pub unsafe fn __rust_start_panic(_payload: &mut dyn PanicPayload) -> u32 {
     unsafe {
         android::android_set_abort_message(_payload);
     }
-    #[cfg(target_os = "zkvm")]
+    #[cfg(any(target_os = "zkvm", target_os = "succinct-zkvm"))]
     unsafe {
         zkvm::zkvm_set_abort_message(_payload);
     }

library/std/Cargo.toml

@@ -163,4 +163,6 @@ check-cfg = [
     # and to the `backtrace` crate which messes-up with Cargo list
     # of declared features, we therefor expect any feature cfg
     'cfg(feature, values(any()))',
+    'cfg(target_os, values("succinct-zkvm"))'
 ]
+

library/std/build.rs

@@ -59,9 +59,9 @@ fn main() {
         || target_os == "uefi"
         || target_os == "teeos"
         || target_os == "zkvm"
+        || target_os == "succinct-zkvm"
         || target_os == "rtems"
         || target_os == "nuttx"
-
         // See src/bootstrap/src/core/build_steps/synthetic_targets.rs
         || env::var("RUSTC_BOOTSTRAP_SYNTHETIC_TARGET").is_ok()
     {

library/std/src/sys/alloc/mod.rs

@@ -88,7 +88,7 @@ cfg_if::cfg_if! {
         mod wasm;
     } else if #[cfg(target_os = "xous")] {
         mod xous;
-    } else if #[cfg(target_os = "zkvm")] {
+    } else if #[cfg(any(target_os = "zkvm", target_os = "succinct-zkvm"))] {
         mod zkvm;
     }
 }

library/std/src/sys/pal/mod.rs

@@ -58,7 +58,7 @@ cfg_if::cfg_if! {
     } else if #[cfg(target_os = "teeos")] {
         mod teeos;
         pub use self::teeos::*;
-    } else if #[cfg(target_os = "zkvm")] {
+    } else if #[cfg(any(target_os = "zkvm", target_os = "succinct-zkvm"))] {
         mod zkvm;
         pub use self::zkvm::*;
     } else {

library/std/src/sys/pal/zkvm/abi.rs

@@ -1,11 +1,6 @@
-//! ABI definitions for symbols exported by risc0-zkvm-platform.
-
-// Included here so we don't have to depend on risc0-zkvm-platform.
-//
-// FIXME: Should we move this to the "libc" crate?  It seems like other
-// architectures put a lot of this kind of stuff there.  But there's
-// currently no risc0 fork of the libc crate, so we'd either have to
-// fork it or upstream it.
+//! ABI definitions for symbols exported by <_>-zkvm targets.
+//! 
+//! Ideally, these should be the minimum viable symbols to support the std-lib.
 
 #![allow(dead_code)]
 pub const DIGEST_WORDS: usize = 8;
@@ -15,9 +10,12 @@ pub mod fileno {
     pub const STDIN: u32 = 0;
     pub const STDOUT: u32 = 1;
     pub const STDERR: u32 = 2;
+
+    #[cfg(target_vendor = "risc0")]
     pub const JOURNAL: u32 = 3;
 }
 
+#[cfg(target_vendor = "risc0")]
 unsafe extern "C" {
     // Wrappers around syscalls provided by risc0-zkvm-platform:
     pub fn sys_halt();
@@ -53,3 +51,27 @@ unsafe extern "C" {
     pub fn sys_alloc_words(nwords: usize) -> *mut u32;
     pub fn sys_alloc_aligned(nwords: usize, align: usize) -> *mut u8;
 }
+
+#[cfg(target_os = "succinct-zkvm")]
+unsafe extern "C" {
+    pub fn sys_halt();
+    pub fn sys_rand(recv_buf: *mut u8, words: usize);
+    pub fn sys_panic(msg_ptr: *const u8, len: usize) -> !;
+    pub fn sys_write(fd: u32, write_buf: *const u8, nbytes: usize);
+    pub fn sys_getenv(
+        recv_buf: *mut u32,
+        words: usize,
+        varname: *const u8,
+        varname_len: usize,
+    ) -> usize;
+    pub fn sys_argv(out_words: *mut u32, out_nwords: usize, arg_index: usize) -> usize;
+    pub fn sys_alloc_aligned(nwords: usize, align: usize) -> *mut u8;
+}
+
+#[cfg(target_os = "succinct-zkvm")]
+// Note: sys_read is not implemented for succinct.
+// However, it is a function used in the standard library, so we need to
+// implement it.
+pub unsafe extern "C" fn sys_read(_: u32, _: *mut u8, _: usize) -> usize {
+    panic!("sys_read not implemented for succinct");
+}

library/std/src/sys/pal/zkvm/args.rs

@@ -1,23 +1,34 @@
-use super::{WORD_SIZE, abi};
 use crate::ffi::OsString;
 use crate::fmt;
-use crate::sys::os_str;
-use crate::sys_common::FromInner;
+
+#[cfg(target_vendor = "risc0")]
+use {
+    super::{WORD_SIZE, abi},
+    crate::sys_common::FromInner,
+    crate::sys::os_str,
+};
 
 pub struct Args {
     i_forward: usize,
     i_back: usize,
     count: usize,
 }
 
+#[cfg(target_vendor = "risc0")]
 pub fn args() -> Args {
     let count = unsafe { abi::sys_argc() };
     Args { i_forward: 0, i_back: 0, count }
 }
 
+#[cfg(target_os = "succinct-zkvm")]
+pub fn args() -> Args {
+    panic!("args not implemented for succinct");
+}
+
 impl Args {
     /// Use sys_argv to get the arg at the requested index. Does not check that i is less than argc
     /// and will not return if the index is out of bounds.
+    #[cfg(target_vendor = "risc0")]
     fn argv(i: usize) -> OsString {
         let arg_len = unsafe { abi::sys_argv(crate::ptr::null_mut(), 0, i) };
 
@@ -36,6 +47,11 @@ impl Args {
             unsafe { crate::slice::from_raw_parts(words.cast() as *const u8, arg_len) };
         OsString::from_inner(os_str::Buf { inner: arg_bytes.to_vec() })
     }
+
+    #[cfg(target_os = "succinct-zkvm")]
+    fn argv(_: usize) -> OsString {
+        panic!("argv not implemented for succinct");
+    }
 }
 
 impl fmt::Debug for Args {

library/std/src/sys/pal/zkvm/mod.rs

@@ -8,8 +8,6 @@
 //! will likely change over time.
 #![forbid(unsafe_op_in_unsafe_fn)]
 
-const WORD_SIZE: usize = size_of::<u32>();
-
 pub mod abi;
 #[path = "../zkvm/args.rs"]
 pub mod args;

library/std/src/sys/pal/zkvm/os.rs

@@ -1,12 +1,17 @@
-use super::{WORD_SIZE, abi, unsupported};
+use super::unsupported;
 use crate::error::Error as StdError;
 use crate::ffi::{OsStr, OsString};
 use crate::marker::PhantomData;
 use crate::path::{self, PathBuf};
-use crate::sys::os_str;
-use crate::sys_common::FromInner;
 use crate::{fmt, io};
 
+#[cfg(target_vendor = "risc0")]
+use {
+    super::{WORD_SIZE, abi},
+    crate::sys::os_str,
+    crate::sys_common::FromInner,
+};
+
 pub fn errno() -> i32 {
     0
 }
@@ -91,6 +96,7 @@ impl fmt::Debug for Env {
     }
 }
 
+#[cfg(target_vendor = "risc0")]
 pub fn getenv(varname: &OsStr) -> Option<OsString> {
     let varname = varname.as_encoded_bytes();
     let nbytes =
@@ -114,6 +120,11 @@ pub fn getenv(varname: &OsStr) -> Option<OsString> {
     Some(OsString::from_inner(os_str::Buf { inner: u8s.to_vec() }))
 }
 
+#[cfg(target_os = "succinct-zkvm")]
+pub fn getenv(_: &OsStr) -> Option<OsString> {
+    panic!("getenv not implemented for succinct");
+}
+
 pub unsafe fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
     Err(io::const_error!(io::ErrorKind::Unsupported, "cannot set env vars on this platform"))
 }

library/std/src/sys/random/mod.rs

@@ -69,7 +69,7 @@ cfg_if::cfg_if! {
     } else if #[cfg(target_os = "wasi")] {
         mod wasi;
         pub use wasi::fill_bytes;
-    } else if #[cfg(target_os = "zkvm")] {
+    } else if #[cfg(any(target_os = "zkvm", target_os = "succinct-zkvm"))] {
         mod zkvm;
         pub use zkvm::fill_bytes;
     } else if #[cfg(any(

library/std/src/sys/random/zkvm.rs

@@ -1,5 +1,6 @@
 use crate::sys::pal::abi;
 
+#[cfg(target_vendor = "risc0")]
 pub fn fill_bytes(bytes: &mut [u8]) {
     let (pre, words, post) = unsafe { bytes.align_to_mut::<u32>() };
     if !words.is_empty() {
@@ -19,3 +20,8 @@ pub fn fill_bytes(bytes: &mut [u8]) {
     pre.copy_from_slice(&buf[..pre.len()]);
     post.copy_from_slice(&buf[pre.len()..pre.len() + post.len()]);
 }
+
+#[cfg(target_vendor = "succinct")]
+pub fn fill_bytes(bytes: &mut [u8]) {
+    unsafe { abi::sys_rand(bytes.as_mut_ptr(), bytes.len()) };
+}

library/std/src/sys/stdio/mod.rs

@@ -28,7 +28,7 @@ cfg_if::cfg_if! {
     } else if #[cfg(target_os = "xous")] {
         mod xous;
         pub use xous::*;
-    } else if #[cfg(target_os = "zkvm")] {
+    } else if #[cfg(any(target_os = "zkvm", target_os = "succinct-zkvm"))] {
         mod zkvm;
         pub use zkvm::*;
     } else {

library/std/src/sys/thread_local/mod.rs

@@ -28,6 +28,7 @@ cfg_if::cfg_if! {
         all(target_family = "wasm", not(target_feature = "atomics")),
         target_os = "uefi",
         target_os = "zkvm",
+        target_os = "succinct-zkvm",
     ))] {
         mod statik;
         pub use statik::{EagerStorage, LazyStorage, thread_local_inner};
@@ -91,6 +92,7 @@ pub(crate) mod guard {
             )),
             target_os = "uefi",
             target_os = "zkvm",
+            target_os = "succinct-zkvm",
         ))] {
             pub(crate) fn enable() {
                 // FIXME: Right now there is no concept of "thread exit" on

library/test/Cargo.toml

@@ -12,3 +12,9 @@ core = { path = "../core", public = true }
 
 [target.'cfg(not(all(windows, target_env = "msvc")))'.dependencies]
 libc = { version = "0.2.150", default-features = false }
+
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = [
+    'cfg(target_os, values("succinct-zkvm"))'
+]

library/test/src/console.rs

@@ -317,7 +317,7 @@ pub fn run_tests_console(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> io::Resu
     // - It's currently not supported for wasm targets without Emscripten nor WASI.
     // - It's currently not supported for zkvm targets.
     let is_instant_unsupported =
-        (cfg!(target_family = "wasm") && cfg!(target_os = "unknown")) || cfg!(target_os = "zkvm");
+        (cfg!(target_family = "wasm") && cfg!(target_os = "unknown")) || cfg!(target_os = "zkvm") || cfg!(target_os = "succinct-zkvm");
 
     let start_time = (!is_instant_unsupported).then(Instant::now);
     run_tests(opts, tests, |x| on_test_event(&x, &mut st, &mut *out))?;

library/test/src/lib.rs

@@ -555,7 +555,7 @@ pub fn run_test(
 
     // Emscripten can catch panics but other wasm targets cannot
     let ignore_because_no_process_support = desc.should_panic != ShouldPanic::No
-        && (cfg!(target_family = "wasm") || cfg!(target_os = "zkvm"))
+        && (cfg!(target_family = "wasm") || cfg!(target_os = "zkvm") || cfg!(target_os = "succinct-zkvm"))
         && !cfg!(target_os = "emscripten");
 
     if force_ignore || desc.ignore || ignore_because_no_process_support {
@@ -604,7 +604,9 @@ pub fn run_test(
             // level.
             let supports_threads = !cfg!(target_os = "emscripten")
                 && !cfg!(target_family = "wasm")
-                && !cfg!(target_os = "zkvm");
+                && !cfg!(target_os = "zkvm")
+                && !cfg!(target_os = "succinct-zkvm");
+
             if supports_threads {
                 let cfg = thread::Builder::new().name(name.as_slice().to_owned());
                 let mut runtest = Arc::new(Mutex::new(Some(runtest)));

src/bootstrap/Cargo.lock

@@ -88,9 +88,8 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.1.22"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9540e661f81799159abee814118cc139a2004b3a3aa3ea37724a1b66530b90e0"
+version = "1.2.0"
+source = "git+https://github.com/nhtyy/cc-rs?branch=n%2Fadd-succinct-target#424acb084e212c330de96e06cab69be0d9df55f4"
 dependencies = [
  "shlex",
 ]

src/bootstrap/Cargo.toml

@@ -39,7 +39,11 @@ test = false
 # otherwise, some targets will fail. That's why these dependencies are explicitly pinned.
 #
 # Do not upgrade this crate unless https://github.com/rust-lang/cc-rs/issues/1317 is fixed.
-cc = "=1.1.22"
+#
+# todo(succinct): remove this change that was explicity against the rules.
+# This just happens to work, and ideally cc-rs will fix the target parsing issue before our target is merged.
+cc = "=1.2.0"
+# cc = "=1.1.22"
 cmake = "=0.1.48"
 
 build_helper = { path = "../build_helper" }
@@ -73,6 +77,9 @@ tracing-chrome = { version = "0.7", optional = true }
 tracing-subscriber = { version = "0.3", optional = true, features = ["env-filter", "fmt", "registry", "std"] }
 tracing-tree = { version = "0.4.0", optional = true }
 
+[patch.crates-io]
+cc = { git = "https://github.com/nhtyy/cc-rs", branch = "n/add-succinct-target" }
+
 [target.'cfg(windows)'.dependencies.junction]
 version = "1.0.0"