Basic 32-bit support for i686

prtest:full

ci/build-test-matrix.js

@@ -36,7 +36,7 @@ function supports32Bit(pkg) {
   if (pkg.indexOf("pulley") !== -1)
     return true;
 
-  return pkg == 'wasmtime-fiber';
+  return pkg == 'wasmtime-fiber' || pkg == 'wasmtime';
 }
 
 // This is the full, unsharded, and unfiltered matrix of what we test on
@@ -231,7 +231,9 @@ async function shard(configs) {
   for (const config of configs) {
     // Special case 32-bit configs. Only some crates, according to
     // `supports32Bit`, run on this target. At this time the set of supported
-    // crates is small enough that they're not sharded.
+    // crates is small enough that they're not sharded. A second shard, however,
+    // is included which runs `--test wast` to run the full `*.wast` test suite
+    // in CI on 32-bit platforms, at this time effectively testing Pulley.
     if (config["32-bit"] === true) {
       sharded.push(Object.assign(
         {},
@@ -242,6 +244,11 @@ async function shard(configs) {
             .join(" "),
         }
       ));
+      sharded.push(Object.assign(
+        {},
+        config,
+        { bucket: '--test wast' },
+      ));
       continue;
     }
 

cranelift/codegen/src/isa/pulley_shared/abi.rs

@@ -1,7 +1,7 @@
 //! Implementation of a standard Pulley ABI.
 
 use super::{inst::*, PulleyFlags, PulleyTargetKind};
-use crate::isa::pulley_shared::PulleyBackend;
+use crate::isa::pulley_shared::{PointerWidth, PulleyBackend};
 use crate::{
     ir::{self, types::*, MemFlags, Signature},
     isa::{self, unwind::UnwindInst},
@@ -533,7 +533,15 @@ where
         _isa_flags: &PulleyFlags,
     ) -> u32 {
         match rc {
-            RegClass::Int => 1,
+            // Spilling an integer register requires spilling 8 bytes, and spill
+            // slots are defined in terms of "word bytes" or the size of a
+            // pointer. That means on 32-bit pulley we need to take up two spill
+            // slots for integers where on 64-bit pulley we need to only take up
+            // one spill slot for integers.
+            RegClass::Int => match P::pointer_width() {
+                PointerWidth::PointerWidth32 => 2,
+                PointerWidth::PointerWidth64 => 1,
+            },
             RegClass::Float => todo!(),
             RegClass::Vector => unreachable!(),
         }

cranelift/jit/src/compiled_blob.rs

@@ -101,6 +101,7 @@ impl CompiledBlob {
                     let what_page = (what as usize) & !0xfff;
                     let at_page = (at as usize) & !0xfff;
                     let pcrel = (what_page as isize).checked_sub(at_page as isize).unwrap();
+                    #[cfg(target_pointer_width = "64")]
                     assert!(
                         (-1 << 32) <= pcrel && pcrel < (1 << 32),
                         "can't reach GOT page with ±4GB `adrp` instruction"

crates/wasi-nn/Cargo.toml

@@ -30,16 +30,18 @@ wasmtime = { workspace = true, features = [
 # These dependencies are necessary for the wasi-nn implementation:
 tracing = { workspace = true }
 thiserror = { workspace = true }
-openvino = { version = "0.8.0", features = [
-    "runtime-linking",
-], optional = true }
 
 ort = { version = "2.0.0-rc.2", default-features = false, features = [
     "copy-dylibs",
     "download-binaries",
 ], optional = true }
 tch = { version = "0.17.0", default-features = false, optional = true}
 
+[target.'cfg(target_pointer_width = "64")'.dependencies]
+openvino = { version = "0.8.0", features = [
+    "runtime-linking",
+], optional = true }
+
 [target.'cfg(windows)'.dependencies.windows]
 version = "0.52"
 features = [

crates/wasi-nn/src/backend/mod.rs

@@ -4,7 +4,7 @@
 
 #[cfg(feature = "onnx")]
 pub mod onnx;
-#[cfg(feature = "openvino")]
+#[cfg(all(feature = "openvino", target_pointer_width = "64"))]
 pub mod openvino;
 #[cfg(feature = "pytorch")]
 pub mod pytorch;
@@ -13,7 +13,7 @@ pub mod winml;
 
 #[cfg(feature = "onnx")]
 use self::onnx::OnnxBackend;
-#[cfg(feature = "openvino")]
+#[cfg(all(feature = "openvino", target_pointer_width = "64"))]
 use self::openvino::OpenvinoBackend;
 #[cfg(feature = "pytorch")]
 use self::pytorch::PytorchBackend;
@@ -31,7 +31,8 @@ use wiggle::GuestError;
 /// Return a list of all available backend frameworks.
 pub fn list() -> Vec<Backend> {
     let mut backends = vec![];
-    #[cfg(feature = "openvino")]
+    let _ = &mut backends; // silence warnings if none are enabled
+    #[cfg(all(feature = "openvino", target_pointer_width = "64"))]
     {
         backends.push(Backend::from(OpenvinoBackend::default()));
     }
@@ -120,6 +121,7 @@ pub enum BackendError {
 }
 
 /// Read a file into a byte vector.
+#[allow(dead_code, reason = "not used on all platforms")]
 fn read(path: &Path) -> anyhow::Result<Vec<u8>> {
     let mut file = File::open(path)?;
     let mut buffer = vec![];

crates/wasmtime/src/engine/serialization.rs

@@ -641,6 +641,8 @@ mod test {
     }
 
     #[test]
+    #[cfg(target_arch = "x86_64")] // test on a platform that is known to use
+                                   // Cranelift
     fn test_os_mismatch() -> Result<()> {
         let engine = Engine::default();
         let mut metadata = Metadata::new(&engine);
@@ -712,6 +714,7 @@ Caused by:
 
     #[test]
     #[cfg_attr(miri, ignore)]
+    #[cfg(target_pointer_width = "64")] // different defaults on 32-bit platforms
     fn test_tunables_int_mismatch() -> Result<()> {
         let engine = Engine::default();
         let mut metadata = Metadata::new(&engine);
@@ -762,6 +765,8 @@ Caused by:
     }
 
     #[test]
+    #[cfg(target_arch = "x86_64")] // test on a platform that is known to
+                                   // implement threads
     fn test_feature_mismatch() -> Result<()> {
         let mut config = Config::new();
         config.wasm_threads(true);

crates/wasmtime/src/runtime/externals/table.rs

@@ -441,6 +441,7 @@ impl Table {
 mod tests {
     use super::*;
     use crate::{Instance, Module, Store};
+    use wasmtime_environ::TripleExt;
 
     #[test]
     fn hash_key_is_stable_across_duplicate_store_data_entries() -> Result<()> {
@@ -452,7 +453,20 @@ mod tests {
                     (table (export "t") 1 1 externref)
                 )
             "#,
-        )?;
+        );
+        // Expect this test to fail on pulley at this time. When pulley supports
+        // externref this should switch back to using `?` on the constructor
+        // above for all platforms.
+        let module = match module {
+            Ok(module) => {
+                assert!(!store.engine().target().is_pulley());
+                module
+            }
+            Err(e) => {
+                assert!(store.engine().target().is_pulley(), "bad error {e:?}");
+                return Ok(());
+            }
+        };
         let instance = Instance::new(&mut store, &module, &[])?;
 
         // Each time we `get_table`, we call `Table::from_wasmtime` which adds

crates/wasmtime/src/runtime/module/registry.rs

@@ -300,6 +300,8 @@ pub fn unregister_code(code: &Arc<CodeMemory>) {
 #[cfg_attr(miri, ignore)]
 fn test_frame_info() -> Result<(), anyhow::Error> {
     use crate::*;
+    use wasmtime_environ::TripleExt;
+
     let mut store = Store::<()>::default();
     let module = Module::new(
         store.engine(),
@@ -314,7 +316,20 @@ fn test_frame_info() -> Result<(), anyhow::Error> {
                 (func (export "rem_u") (param $x i32) (param $y i32) (result i32) (i32.rem_u (local.get $x) (local.get $y)))
             )
          "#,
-    )?;
+    );
+    // Expect this test to fail on pulley at this time. When pulley supports
+    // the instructions above this should switch back to using `?` on the
+    // constructor above for all platforms.
+    let module = match module {
+        Ok(module) => {
+            assert!(!store.engine().target().is_pulley());
+            module
+        }
+        Err(e) => {
+            assert!(store.engine().target().is_pulley(), "bad error {e:?}");
+            return Ok(());
+        }
+    };
     // Create an instance to ensure the frame information is registered.
     Instance::new(&mut store, &module, &[])?;
 

crates/wasmtime/src/runtime/values.rs

@@ -1021,26 +1021,14 @@ mod tests {
     fn size_of_val() {
         // Try to keep tabs on the size of `Val` and make sure we don't grow its
         // size.
-        assert_eq!(
-            std::mem::size_of::<Val>(),
-            if cfg!(any(
-                target_arch = "x86_64",
-                target_arch = "aarch64",
-                target_arch = "riscv64",
-                target_arch = "s390x"
-            )) {
-                24
-            } else {
-                panic!("unsupported architecture")
-            }
-        );
+        assert!(std::mem::size_of::<Val>() <= 24);
     }
 
     #[test]
     fn size_of_ref() {
         // Try to keep tabs on the size of `Ref` and make sure we don't grow its
         // size.
-        assert_eq!(std::mem::size_of::<Ref>(), 24);
+        assert!(std::mem::size_of::<Ref>() <= 24);
     }
 
     #[test]

crates/wasmtime/src/runtime/vm/arch/x86_64.rs → crates/wasmtime/src/runtime/vm/arch/arm.rs

@@ -1,12 +1,12 @@
-//! x86_64-specific definitions of architecture-specific functions in Wasmtime.
+//! arm-specific definitions of architecture-specific functions in Wasmtime.
 
 #[inline]
 #[allow(missing_docs)]
 pub fn get_stack_pointer() -> usize {
     let stack_pointer: usize;
     unsafe {
         core::arch::asm!(
-            "mov {}, rsp",
+            "mov {}, sp",
             out(reg) stack_pointer,
             options(nostack,nomem),
         );
@@ -24,5 +24,5 @@ pub unsafe fn get_next_older_pc_from_fp(fp: usize) -> usize {
 pub const NEXT_OLDER_FP_FROM_FP_OFFSET: usize = 0;
 
 pub fn assert_fp_is_aligned(fp: usize) {
-    assert_eq!(fp % 16, 0, "stack should always be aligned to 16");
+    assert_eq!(fp % 8, 0, "stack should always be aligned to 8");
 }

crates/wasmtime/src/runtime/vm/arch/mod.rs

@@ -8,9 +8,9 @@
 //! crate.
 
 cfg_if::cfg_if! {
-    if #[cfg(target_arch = "x86_64")] {
-        mod x86_64;
-        use x86_64 as imp;
+    if #[cfg(any(target_arch = "x86_64", target_arch = "x86"))] {
+        mod x86;
+        use x86 as imp;
     } else if #[cfg(target_arch = "aarch64")] {
         mod aarch64;
         use aarch64 as imp;
@@ -20,6 +20,9 @@ cfg_if::cfg_if! {
     } else if #[cfg(target_arch = "riscv64")] {
         mod riscv64;
         use riscv64 as imp;
+    } else if #[cfg(target_arch = "arm")] {
+        mod arm;
+        use arm as imp;
     } else {
         mod unsupported;
         use unsupported as imp;

crates/wasmtime/src/runtime/vm/arch/unsupported.rs

@@ -1,15 +1,7 @@
 compile_error!("Wasmtime's runtime is being compiled for an architecture that it does not support");
 
 cfg_if::cfg_if! {
-    if #[cfg(target_arch = "x86")] {
-    compile_error!("\
-the tracking issue for i686 support is https://github.com/bytecodealliance/wasmtime/issues/1980 \
-");
-    } else if #[cfg(target_arch = "arm")] {
-    compile_error!("\
-the tracking issue for arm support is https://github.com/bytecodealliance/wasmtime/issues/1173 \
-");
-    } else if #[cfg(target_arch = "riscv32")] {
+    if #[cfg(target_arch = "riscv32")] {
     compile_error!("\
 the tracking issue for riscv32 support is https://github.com/bytecodealliance/wasmtime/issues/8768 \
 ");

crates/wasmtime/src/runtime/vm/arch/x86.rs

@@ -0,0 +1,39 @@
+//! x86-specific (also x86-64) definitions of architecture-specific functions in
+//! Wasmtime.
+
+#[inline]
+#[allow(missing_docs)]
+pub fn get_stack_pointer() -> usize {
+    let stack_pointer: usize;
+    unsafe {
+        #[cfg(target_pointer_width = "64")]
+        core::arch::asm!(
+            "mov {}, rsp",
+            out(reg) stack_pointer,
+            options(nostack,nomem),
+        );
+        #[cfg(target_pointer_width = "32")]
+        core::arch::asm!(
+            "mov {}, esp",
+            out(reg) stack_pointer,
+            options(nostack,nomem),
+        );
+    }
+    stack_pointer
+}
+
+pub unsafe fn get_next_older_pc_from_fp(fp: usize) -> usize {
+    // The calling convention always pushes the return pointer (aka the PC of
+    // the next older frame) just before this frame.
+    *(fp as *mut usize).offset(1)
+}
+
+// And the current frame pointer points to the next older frame pointer.
+pub const NEXT_OLDER_FP_FROM_FP_OFFSET: usize = 0;
+
+/// Frame pointers are aligned if they're aligned to twice the size of a
+/// pointer.
+pub fn assert_fp_is_aligned(fp: usize) {
+    let align = 2 * size_of::<usize>();
+    assert_eq!(fp % align, 0, "stack should always be aligned to {align}");
+}

crates/wasmtime/src/runtime/vm/gc/enabled/drc.rs

@@ -985,6 +985,7 @@ impl<T> DerefMut for DebugOnly<T> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use wasmtime_environ::HostPtr;
 
     #[test]
     fn vm_drc_header_size_align() {
@@ -1019,7 +1020,7 @@ mod tests {
         let actual_offset = (ref_count_ptr as usize) - (extern_data_ptr as usize);
 
         let offsets = wasmtime_environ::VMOffsets::from(wasmtime_environ::VMOffsetsFields {
-            ptr: 8,
+            ptr: HostPtr,
             num_imported_functions: 0,
             num_imported_tables: 0,
             num_imported_memories: 0,
@@ -1047,7 +1048,7 @@ mod tests {
         let actual_offset = (next_ptr as usize) - (table_ptr as usize);
 
         let offsets = wasmtime_environ::VMOffsets::from(wasmtime_environ::VMOffsetsFields {
-            ptr: 8,
+            ptr: HostPtr,
             num_imported_functions: 0,
             num_imported_tables: 0,
             num_imported_memories: 0,
@@ -1074,7 +1075,7 @@ mod tests {
         let actual_offset = (end_ptr as usize) - (table_ptr as usize);
 
         let offsets = wasmtime_environ::VMOffsets::from(wasmtime_environ::VMOffsetsFields {
-            ptr: 8,
+            ptr: HostPtr,
             num_imported_functions: 0,
             num_imported_tables: 0,
             num_imported_memories: 0,

crates/wasmtime/src/runtime/vm/instance/allocator/pooling.rs

@@ -699,6 +699,7 @@ unsafe impl InstanceAllocatorImpl for PoolingInstanceAllocator {
 }
 
 #[cfg(test)]
+#[cfg(target_pointer_width = "64")]
 mod test {
     use super::*;