Add wasm32-wasmer-wasi-dl target, add WASIX dylib support

Arshia001 · Arshia001 · commit 9d6e3b8ee59b · 2025-06-23T10:00:20.000Z
diff --git a/build-wasix.sh b/build-wasix.sh
@@ -0,0 +1,18 @@
+#!/bin/bash
+
+set -euo pipefail
+
+cd src/llvm-project
+git status | grep WebAssemblyISelLowering.cpp &> /dev/null
+if [ $? -ne 0 ]; then
+    git apply ../../wasix-llvm.patch
+fi
+cd ../..
+
+./x.py build --target=wasm32-wasmer-wasi --stage 2
+./x.py build --target=wasm32-wasmer-wasi-dl --stage 2
+
+rustup toolchain uninstall wasix-dev
+rustup toolchain link wasix-dev ./build/host/stage2
+
+echo Done
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -1,3 +1,4 @@
+use core::iter::Iterator;
 use std::collections::BTreeSet;
 use std::ffi::OsString;
 use std::fs::{File, OpenOptions, read};
@@ -1116,16 +1117,22 @@ fn link_natively(
     if sess.target.is_like_osx {
         let stripcmd = "rust-objcopy";
         match (strip, crate_type) {
-            (Strip::Debuginfo, _) => {
-                strip_symbols_with_external_utility(sess, stripcmd, out_filename, Some("--strip-debug"))
-            }
+            (Strip::Debuginfo, _) => strip_symbols_with_external_utility(
+                sess,
+                stripcmd,
+                out_filename,
+                Some("--strip-debug"),
+            ),
             // Per the manpage, `-x` is the maximum safe strip level for dynamic libraries. (#93988)
             (Strip::Symbols, CrateType::Dylib | CrateType::Cdylib | CrateType::ProcMacro) => {
                 strip_symbols_with_external_utility(sess, stripcmd, out_filename, Some("-x"))
             }
-            (Strip::Symbols, _) => {
-                strip_symbols_with_external_utility(sess, stripcmd, out_filename, Some("--strip-all"))
-            }
+            (Strip::Symbols, _) => strip_symbols_with_external_utility(
+                sess,
+                stripcmd,
+                out_filename,
+                Some("--strip-all"),
+            ),
             (Strip::None, _) => {}
         }
     }
@@ -2986,6 +2993,11 @@ fn add_dynamic_crate(cmd: &mut dyn Linker, sess: &Session, cratepath: &Path) {
 }
 
 fn relevant_lib(sess: &Session, lib: &NativeLib) -> bool {
+    if sess.target.is_like_wasm && lib.name.as_str() == "c" {
+        // For wasm targets, WasmLd decides whether to link libc based on
+        // the output kind, so we skip it here.
+        return false;
+    }
     match lib.cfg {
         Some(ref cfg) => rustc_attr::cfg_matches(cfg, sess, CRATE_NODE_ID, None),
         None => true,
diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -1278,7 +1278,7 @@ impl<'a> WasmLd<'a> {
         //      symbols are how the TLS segments are initialized and configured.
         let mut wasm_ld = WasmLd { cmd, sess };
         if sess.target_features.contains(&sym::atomics) {
-            wasm_ld.link_args(&["--shared-memory", "--max-memory=1073741824", "--import-memory"]);
+            wasm_ld.link_args(&["--shared-memory", "--max-memory=4294967296", "--import-memory"]);
             if sess.target.os == "unknown" || sess.target.os == "none" {
                 wasm_ld.link_args(&[
                     "--export=__wasm_init_tls",
@@ -1304,11 +1304,38 @@ impl<'a> Linker for WasmLd<'a> {
         _out_filename: &Path,
     ) {
         match output_kind {
-            LinkOutputKind::DynamicNoPicExe
-            | LinkOutputKind::DynamicPicExe
-            | LinkOutputKind::StaticNoPicExe
-            | LinkOutputKind::StaticPicExe => {}
-            LinkOutputKind::DynamicDylib | LinkOutputKind::StaticDylib => {
+            LinkOutputKind::DynamicNoPicExe | LinkOutputKind::StaticNoPicExe => {}
+            LinkOutputKind::StaticPicExe | LinkOutputKind::DynamicPicExe => {
+                // FIXME: The wasm32-wasmer-wasi-dl toolchain produces broken executables
+                // right now, because the start function isn't linked correctly. Instead of
+                // _start calling the rust main function, it calls __main_void from libc,
+                // which is broken because rustc does not generate a __main_argc_argv.
+                // ... probably because we're linking in libc's _start and overriding rustc's?
+
+                self.link_args(["-pie", "--export-all", "--no-gc-sections"]);
+
+                // We link and export all of libc, as well as all of rust's stdlib into dynamic
+                // executables, so that side modules can just link against the existing code at
+                // runtime. This has two benefits:
+                //  * Reduced code size for side modules
+                //  * More importantly, static and thread-local variables will exist only once.
+                //    This is especially important for libc, which stores things such as the
+                //    state of its memory allocator (malloc et al.) in static variables.
+                let whole_archive = true;
+                let verbatim = false; // No effect for WasmLd
+                self.link_staticlib_by_name("c", verbatim, whole_archive);
+                self.link_staticlib_by_name("resolv", verbatim, whole_archive);
+                self.link_staticlib_by_name("rt", verbatim, whole_archive);
+                self.link_staticlib_by_name("m", verbatim, whole_archive);
+                self.link_staticlib_by_name("pthread", verbatim, whole_archive);
+                self.link_staticlib_by_name("util", verbatim, whole_archive);
+                self.link_staticlib_by_name("wasi-emulated-mman", verbatim, whole_archive);
+                self.link_staticlib_by_name("common-tag-stubs", verbatim, whole_archive);
+            }
+            LinkOutputKind::DynamicDylib => {
+                self.link_args(["--no-entry", "-shared", "--unresolved-symbols=import-dynamic"]);
+            }
+            LinkOutputKind::StaticDylib => {
                 self.link_arg("--no-entry");
             }
             LinkOutputKind::WasiReactorExe => {
@@ -1394,7 +1421,7 @@ impl<'a> Linker for WasmLd<'a> {
 
     fn no_default_libraries(&mut self) {}
 
-    fn export_symbols(&mut self, _tmpdir: &Path, _crate_type: CrateType, symbols: &[String]) {
+    fn export_symbols(&mut self, _tmpdir: &Path, crate_type: CrateType, symbols: &[String]) {
         for sym in symbols {
             self.link_args(&["--export", sym]);
         }
@@ -1403,7 +1430,23 @@ impl<'a> Linker for WasmLd<'a> {
         // symbols explicitly passed via the `--export` flags above and hides all
         // others. Various bits and pieces of wasm32-unknown-unknown tooling use
         // this, so be sure these symbols make their way out of the linker as well.
-        self.link_args(&["--export=__heap_base", "--export=__data_end", "--export=__stack_pointer"]);
+        self.link_args(&[
+            "--export=__wasm_init_tls",
+            "--export=__tls_size",
+            "--export=__tls_align",
+            "--export=__tls_base",
+            "--export=__wasm_call_ctors",
+            "--export=__wasm_signal",
+            "--export-if-defined=__wasm_apply_data_relocs",
+        ]);
+
+        if matches!(crate_type, CrateType::Executable) {
+            self.link_args(&[
+                "--export-if-defined=__stack_pointer",
+                "--export-if-defined=__heap_base",
+                "--export-if-defined=__data_end",
+            ]);
+        }
     }
 
     fn subsystem(&mut self, _subsystem: &str) {}
diff --git a/compiler/rustc_target/src/spec/crt_objects.rs b/compiler/rustc_target/src/spec/crt_objects.rs
@@ -115,6 +115,8 @@ pub(super) fn pre_wasi_self_contained() -> CrtObjects {
         (LinkOutputKind::DynamicPicExe, &["crt1-command.o"]),
         (LinkOutputKind::StaticNoPicExe, &["crt1-command.o"]),
         (LinkOutputKind::StaticPicExe, &["crt1-command.o"]),
+        (LinkOutputKind::DynamicDylib, &["scrt1.o"]),
+        (LinkOutputKind::StaticDylib, &["scrt1.o"]),
         (LinkOutputKind::WasiReactorExe, &["crt1-reactor.o"]),
     ])
 }
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
@@ -1333,9 +1333,9 @@ impl StackProbeType {
                     .and_then(|o| o.as_array())
                     .ok_or_else(|| "expected `min-llvm-version-for-inline` to be an array")?;
                 let mut iter = min_version.into_iter().map(|v| {
-                    let int = v.as_u64().ok_or_else(|| {
-                        "expected `min-llvm-version-for-inline` values to be integers"
-                    })?;
+                    let int = v.as_u64().ok_or_else(
+                        || "expected `min-llvm-version-for-inline` values to be integers",
+                    )?;
                     u32::try_from(int)
                         .map_err(|_| "`min-llvm-version-for-inline` values don't convert to u32")
                 });
@@ -1809,6 +1809,7 @@ supported_targets! {
     ("wasm32-wasip2", wasm32_wasip2),
     ("wasm32-wasip1-threads", wasm32_wasip1_threads),
     ("wasm32-wasmer-wasi", wasm32_wasmer_wasi),
+    ("wasm32-wasmer-wasi-dl", wasm32_wasmer_wasi_dl),
     ("wasm64-unknown-emscripten", wasm64_unknown_emscripten),
     ("wasm64-unknown-unknown", wasm64_unknown_unknown),
     ("wasm64-wasmer-wasi", wasm64_wasmer_wasi),
@@ -3462,10 +3463,10 @@ impl Target {
 
         // Each field should have been read using `Json::remove` so any keys remaining are unused.
         let remaining_keys = obj.keys();
-        Ok((base, TargetWarnings {
-            unused_fields: remaining_keys.cloned().collect(),
-            incorrect_type,
-        }))
+        Ok((
+            base,
+            TargetWarnings { unused_fields: remaining_keys.cloned().collect(), incorrect_type },
+        ))
     }
 
     /// Load a built-in target
diff --git a/compiler/rustc_target/src/spec/targets/wasm32_wasmer_wasi.rs b/compiler/rustc_target/src/spec/targets/wasm32_wasmer_wasi.rs
@@ -71,22 +71,31 @@
 //! best we can with this target. Don't start relying on too much here unless
 //! you know what you're getting in to!
 
-use crate::spec::{base, crt_objects, Cc, LinkSelfContainedDefault, LinkerFlavor, Target};
+use crate::spec::{Cc, LinkSelfContainedDefault, LinkerFlavor, Target, base, crt_objects};
 
 pub(crate) fn target() -> Target {
+    macro_rules! args {
+        ($prefix:literal) => {
+            &[
+                // We need shared memory for multithreading
+                concat!($prefix, "--shared-memory"),
+                concat!($prefix, "--import-memory"),
+                concat!($prefix, "--export-dynamic"),
+                concat!($prefix, "--no-check-features"),
+                concat!($prefix, "-mllvm"),
+                concat!($prefix, "--wasm-enable-sjlj"),
+            ]
+        };
+    }
+
     let mut options = base::wasm::options();
 
     options.os = "wasi".into();
     options.vendor = "wasmer".into();
-    options.add_pre_link_args(
-        LinkerFlavor::WasmLld(Cc::Yes),
-        &[
-            "--target=wasm32-wasi",
-            // We need shared memory for multithreading
-            "--shared-memory",
-            "--no-check-features",
-        ],
-    );
+    options.add_pre_link_args(LinkerFlavor::WasmLld(Cc::Yes), &["--target=wasm32-wasi"]);
+
+    options.add_pre_link_args(LinkerFlavor::WasmLld(Cc::Yes), args!("-Wl,"));
+    options.add_pre_link_args(LinkerFlavor::WasmLld(Cc::No), args!(""));
 
     options.pre_link_objects_self_contained = crt_objects::pre_wasi_self_contained();
     options.post_link_objects_self_contained = crt_objects::post_wasi_self_contained();
diff --git a/compiler/rustc_target/src/spec/targets/wasm32_wasmer_wasi_dl.rs b/compiler/rustc_target/src/spec/targets/wasm32_wasmer_wasi_dl.rs
@@ -0,0 +1,19 @@
+//! `wasm32-wasmer-wasi` with support for dynamic linking.
+
+use crate::spec::{RelocModel, Target, TlsModel};
+
+pub(crate) fn target() -> Target {
+    let mut target = super::wasm32_wasmer_wasi::target();
+
+    target.env = "dl".into();
+
+    target.options.dll_prefix = "lib".into();
+    target.options.dll_suffix = ".so".into();
+
+    target.options.relocation_model = RelocModel::Pic;
+    target.options.tls_model = TlsModel::GeneralDynamic;
+    target.options.crt_static_default = false;
+    target.options.position_independent_executables = true;
+
+    target
+}
diff --git a/config.toml b/config.toml
@@ -1,9 +1,9 @@
 change-id = 125535
 
 [build]
-target = ["wasm32-wasmer-wasi", "wasm64-wasmer-wasi"]
+target = ["wasm32-wasmer-wasi", "wasm32-wasmer-wasi-dl"]
 extended = true
-tools = [ "clippy", "rustfmt" ]
+tools = ["cargo", "clippy", "rustfmt"]
 configure-args = []
 
 [rust]
@@ -14,7 +14,7 @@ llvm-tools = true
 download-ci-llvm = false
 
 [target.wasm32-wasmer-wasi]
-wasi-root = "../wasix-libc/sysroot32"
+wasi-root = "../wasix-libc/sysroot32-eh"
 
-[target.wasm64-wasmer-wasi]
-wasi-root = "../wasix-libc/sysroot64"
+[target.wasm32-wasmer-wasi-dl]
+wasi-root = "../wasix-libc/sysroot32-ehpic"
diff --git a/library/std/Cargo.toml b/library/std/Cargo.toml
@@ -34,7 +34,9 @@ miniz_oxide = { version = "0.7.0", optional = true, default-features = false }
 addr2line = { version = "0.22.0", optional = true, default-features = false }
 
 [target.'cfg(not(all(windows, target_env = "msvc")))'.dependencies]
-libc = { git = "https://github.com/wasix-org/libc.git", branch = "wasix-0.2.164", version = "0.2.164", default-features = false, features = ['rustc-dep-of-std'], public = true }
+libc = { git = "https://github.com/wasix-org/libc.git", branch = "wasix-0.2.164", version = "0.2.164", default-features = false, features = [
+    'rustc-dep-of-std',
+], public = true }
 
 [target.'cfg(all(not(target_os = "aix"), not(all(windows, target_env = "msvc", not(target_vendor = "uwp")))))'.dependencies]
 object = { version = "0.36.0", default-features = false, optional = true, features = [
@@ -80,10 +82,19 @@ wasi = { version = "0.11.0", features = [
 ], default-features = false }
 
 [target.wasm32-wasmer-wasi.dependencies]
-wasi = { package = "wasix", version = "0.13.0", features = ['rustc-dep-of-std'], default-features = false, public = true }
+wasi = { package = "wasix", version = "0.13.0", features = [
+    'rustc-dep-of-std',
+], default-features = false, public = true }
+
+[target.wasm32-wasmer-wasi-dl.dependencies]
+wasi = { package = "wasix", version = "0.13.0", features = [
+    'rustc-dep-of-std',
+], default-features = false, public = true }
 
 [target.wasm64-wasmer-wasi.dependencies]
-wasi = { package = "wasix", version = "0.13.0", features = ['rustc-dep-of-std'], default-features = false, public = true }
+wasi = { package = "wasix", version = "0.13.0", features = [
+    'rustc-dep-of-std',
+], default-features = false, public = true }
 
 [target.'cfg(target_os = "uefi")'.dependencies]
 r-efi = { version = "4.5.0", features = ['rustc-dep-of-std'] }
@@ -145,6 +156,7 @@ check-cfg = [
     'cfg(bootstrap)',
     'cfg(target_arch, values("xtensa"))',
     'cfg(target_vendor, values("wasmer"))',
+    'cfg(target_env, values("dl"))',
     # std use #[path] imports to portable-simd `std_float` crate
     # and to the `backtrace` crate which messes-up with Cargo list
     # of declared features, we therefor expect any feature cfg
diff --git a/src/bootstrap/src/core/build_steps/compile.rs b/src/bootstrap/src/core/build_steps/compile.rs
@@ -392,7 +392,28 @@ fn copy_self_contained_objects(
                 target.triple
             )
         });
-        for &obj in &["libc.a", "crt1-command.o", "crt1-reactor.o"] {
+        let mut files = vec!["libc.a", "crt1-command.o", "crt1-reactor.o"];
+        if target.contains("-dl") {
+            files.extend([
+                // Needed for DL side modules.
+                "scrt1.o",
+                // Need to bring these over for DL main module builds, so we can embed them.
+                "libcommon-tag-stubs.a",
+                "libcrypt.a",
+                "libwasi-emulated-mman.a",
+                "libresolv.a",
+                "librt.a",
+                "libm.a",
+                "libpthread.a",
+                "libutil.a",
+                // We don't link c++ libs in, but we bring them over anyway so that, when
+                // a rust program needs to load C++-based dylibs, the user can link these
+                // in manually via linker flags.
+                "libc++.a",
+                "libc++abi.a",
+            ]);
+        }
+        for obj in files {
             copy_and_stamp(
                 builder,
                 &libdir_self_contained,
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
diff --git a/wasix-llvm.patch b/wasix-llvm.patch

Original file line number	Diff line number	Diff line change
`@@ -115,6 +115,8 @@ pub(super) fn pre_wasi_self_contained() -> CrtObjects {`
`115`	`115`	`(LinkOutputKind::DynamicPicExe, &["crt1-command.o"]),`
`116`	`116`	`(LinkOutputKind::StaticNoPicExe, &["crt1-command.o"]),`
`117`	`117`	`(LinkOutputKind::StaticPicExe, &["crt1-command.o"]),`
	`118`	`+ (LinkOutputKind::DynamicDylib, &["scrt1.o"]),`
	`119`	`+ (LinkOutputKind::StaticDylib, &["scrt1.o"]),`
`118`	`120`	`(LinkOutputKind::WasiReactorExe, &["crt1-reactor.o"]),`
`119`	`121`	`])`
`120`	`122`	`}`