`wasm32v1-none` still creates incorrect object files

[StackOverflowExcept1on]

@alexcrichton

I thought this had been fixed in #145275. But it seems that the problem still exists.

foo.rs

#![no_core]
#![crate_type = "cdylib"]
#![feature(no_core)]

rustc +nightly-2025-08-16 foo.rs --target wasm32v1-none -C linker-plugin-lto=on && wasm-dis foo.wasm

(module $foo.wasm
 (import "env" "memory" (memory $mimport$0 16))
 (global $__stack_pointer (mut i32) (i32.const 1048576))
 (global $global$1 i32 (i32.const 1048576))
 (global $global$2 i32 (i32.const 1048576))
 (export "__data_end" (global $global$1))
 (export "__heap_base" (global $global$2))
 ;; custom section "producers", size 59
 ;; features section: mutable-globals, nontrapping-float-to-int, bulk-memory, sign-ext, reference-types, multivalue
)

target_features should not have anything other than mutable-globals: https://doc.rust-lang.org/rustc/platform-support/wasm32v1-none.html#enabled-webassembly-features

Meta

rustc +nightly-2025-08-16 --version --verbose:

rustc 1.91.0-nightly (cd7cbe818 2025-08-15)
binary: rustc
commit-hash: cd7cbe818e4a66d46fe2df993d1b8518eba8a5cd
commit-date: 2025-08-15
host: x86_64-unknown-linux-gnu
release: 1.91.0-nightly
LLVM version: 21.1.0

[StackOverflowExcept1on]

this case is related to wasm-ld:

RUSTC_LOG="rustc_codegen_ssa::back::link=info" rustc +nightly-2025-08-16 foo.rs --target wasm32v1-none -C linker-plugin-lto=on -C link-arg=--verbose && wasm-dis foo.wasm

 rust-lld: -- populateTargetFeatures
 rust-lld: Allowed feature: call-indirect-overlong
 rust-lld: Allowed feature: nontrapping-fptoint
 rust-lld: Allowed feature: mutable-globals
 rust-lld: Allowed feature: reference-types
 rust-lld: Allowed feature: bulk-memory
 rust-lld: Allowed feature: multivalue
 rust-lld: Allowed feature: sign-ext
 rust-lld: Allowed feature: bulk-memory-opt

[StackOverflowExcept1on]

wat.ll

LLVM version: 20.1.8

target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-S128-ni:1:10:20"
target triple = "wasm32-unknown-unknown"

llvm-as wat.ll
wasm-ld wat.bc -o foo.wasm --no-entry
wasm-dis foo.wasm

(module $foo.wasm
 (global $__stack_pointer (mut i32) (i32.const 66560))
 (memory $0 2)
 (export "memory" (memory $0))
 ;; features section: mutable-globals, nontrapping-float-to-int, bulk-memory, sign-ext, reference-types, multivalue
)

[StackOverflowExcept1on]

foo.rs

#![no_core]
#![crate_type = "lib"]
#![feature(no_core, lang_items, allocator_internals, rustc_attrs)]
#![needs_allocator]
#![allow(internal_features)]

#[rustc_std_internal_symbol]
unsafe fn __rust_alloc(_size: usize, _align: usize) -> *mut u8 {
    0 as *mut u8
}

unsafe extern "Rust" {
    #[rustc_std_internal_symbol]
    fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
}

#[used]
static mut BUF: [u8; 1024] = [0; 1024];

#[unsafe(no_mangle)]
extern "C" fn init() {
    unsafe {
        __rust_alloc_error_handler(0, 0);
    }
}

mod minicore {
    #[lang = "pointee_sized"]
    pub trait PointeeSized {}

    #[lang = "meta_sized"]
    pub trait MetaSized: PointeeSized {}

    #[lang = "sized"]
    pub trait Sized: MetaSized {}

    #[lang = "copy"]
    pub trait Copy {}
    impl Copy for u8 {}

    #[lang = "drop_in_place"]
    fn drop_in_place<T>(_: *mut T) {}
}

bar.rs

#![no_core]
#![crate_type = "cdylib"]
#![feature(no_core)]

extern crate foo;

#[allow(unused_imports)]
pub use foo::*;

rustc +nightly-2025-08-17 foo.rs --target wasm32v1-none
rustc +nightly-2025-08-17 bar.rs --target wasm32v1-none --extern foo=libfoo.rlib -C linker-plugin-lto=on -C link-arg=--import-memory && wasm-dis ./bar.wasm

(module $bar.wasm
 (type $0 (func (param i32 i32)))
 (type $1 (func))
 (import "env" "memory" (memory $mimport$0 17))
 (import "env" "_RNvCs4pED7du1fNF_7___rustc9___rdl_oom" (func $_RNvCs4pED7du1fNF_7___rustc9___rdl_oom (param i32 i32)))
 (global $__stack_pointer (mut i32) (i32.const 1048576))
 (global $global$1 i32 (i32.const 1049600))
 (global $global$2 i32 (i32.const 1049600))
 (export "init" (func $init))
 (export "__data_end" (global $global$1))
 (export "__heap_base" (global $global$2))
 (start $__wasm_init_memory)
 (func $__wasm_init_memory
  (memory.fill
   (i32.const 1048576)
   (i32.const 0)
   (i32.const 1024)
  )
 )
 (func $init
  (local $0 i32)
  (local.set $0
   (i32.const 0)
  )
  (call $_RNvCs4pED7du1fNF_7___rustc26___rust_alloc_error_handler
   (local.get $0)
   (local.get $0)
  )
  (unreachable)
 )
 (func $_RNvCs4pED7du1fNF_7___rustc26___rust_alloc_error_handler (param $0 i32) (param $1 i32)
  (call $_RNvCs4pED7du1fNF_7___rustc9___rdl_oom
   (local.get $0)
   (local.get $1)
  )
 )
 ;; custom section "producers", size 59
 ;; features section: mutable-globals, nontrapping-float-to-int, bulk-memory, sign-ext, reference-types, multivalue
)

[StackOverflowExcept1on]

looks like wasm-ld enabled all features
https://github.com/llvm/llvm-project/blob/71925a90c8b713d8fccbfae496e10c68f80b932b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp#L331-L339

rust-lld -flavor wasm --export=__heap_base --export=__data_end -z stack-size=1048576 --stack-first --allow-undefined --no-demangle --no-entry foo.foo.d830c44fddf33c90-cgu.0.rcgu.o --lto-O0 -L /root/.../rust/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/wasm32v1-none/lib/self-contained -o foo.wasm --gc-sections --no-entry -O0 --verbose

[StackOverflowExcept1on]

@nikic can you please take a look at this? Probably we need some way to set WasmTM->CPU = "mvp" in wasm-ld for wasm32v1-none target. Also I think wasm-ld --mllvm=-mcpu=mvp --mllvm=-mattr=+mutable-globals can solve the problem.