Merge #1192

1192: Use `ExceptionCode` for error representation. r=losfair a=losfair

Extends #1129 to all backends.

Co-authored-by: losfair <[email protected]>

lib/clif-backend/src/signal/mod.rs

@@ -8,7 +8,7 @@ use std::{any::Any, cell::Cell, ptr::NonNull, sync::Arc};
 use wasmer_runtime_core::{
     backend::RunnableModule,
     module::ModuleInfo,
-    typed_func::{Trampoline, Wasm, WasmTrapInfo},
+    typed_func::{Trampoline, Wasm},
     types::{LocalFuncIndex, SigIndex},
     vm,
 };
@@ -29,10 +29,7 @@ thread_local! {
     pub static TRAP_EARLY_DATA: Cell<Option<Box<dyn Any + Send>>> = Cell::new(None);
 }
 
-pub enum CallProtError {
-    Trap(WasmTrapInfo),
-    Error(Box<dyn Any + Send>),
-}
+pub struct CallProtError(pub Box<dyn Any + Send>);
 
 pub struct Caller {
     handler_data: HandlerData,
@@ -66,8 +63,7 @@ impl RunnableModule for Caller {
             func: NonNull<vm::Func>,
             args: *const u64,
             rets: *mut u64,
-            trap_info: *mut WasmTrapInfo,
-            user_error: *mut Option<Box<dyn Any + Send>>,
+            error_out: *mut Option<Box<dyn Any + Send>>,
             invoke_env: Option<NonNull<c_void>>,
         ) -> bool {
             let handler_data = &*invoke_env.unwrap().cast().as_ptr();
@@ -84,10 +80,7 @@ impl RunnableModule for Caller {
 
             match res {
                 Err(err) => {
-                    match err {
-                        CallProtError::Trap(info) => *trap_info = info,
-                        CallProtError::Error(data) => *user_error = Some(data),
-                    }
+                    *error_out = Some(err.0);
                     false
                 }
                 Ok(()) => true,

lib/clif-backend/src/signal/unix.rs

@@ -18,7 +18,7 @@ use nix::sys::signal::{
 use std::cell::{Cell, UnsafeCell};
 use std::ptr;
 use std::sync::Once;
-use wasmer_runtime_core::typed_func::WasmTrapInfo;
+use wasmer_runtime_core::backend::ExceptionCode;
 
 extern "C" fn signal_trap_handler(
     signum: ::nix::libc::c_int,
@@ -79,7 +79,7 @@ pub fn call_protected<T>(
             *jmp_buf = prev_jmp_buf;
 
             if let Some(data) = super::TRAP_EARLY_DATA.with(|cell| cell.replace(None)) {
-                Err(CallProtError::Error(data))
+                Err(CallProtError(data))
             } else {
                 let (faulting_addr, inst_ptr) = CAUGHT_ADDRESSES.with(|cell| cell.get());
 
@@ -88,21 +88,25 @@ pub fn call_protected<T>(
                     srcloc: _,
                 }) = handler_data.lookup(inst_ptr)
                 {
-                    Err(CallProtError::Trap(match Signal::from_c_int(signum) {
+                    Err(CallProtError(Box::new(match Signal::from_c_int(signum) {
                         Ok(SIGILL) => match trapcode {
-                            TrapCode::BadSignature => WasmTrapInfo::IncorrectCallIndirectSignature,
-                            TrapCode::IndirectCallToNull => WasmTrapInfo::CallIndirectOOB,
-                            TrapCode::HeapOutOfBounds => WasmTrapInfo::MemoryOutOfBounds,
-                            TrapCode::TableOutOfBounds => WasmTrapInfo::CallIndirectOOB,
-                            _ => WasmTrapInfo::Unknown,
+                            TrapCode::BadSignature => ExceptionCode::IncorrectCallIndirectSignature,
+                            TrapCode::IndirectCallToNull => ExceptionCode::CallIndirectOOB,
+                            TrapCode::HeapOutOfBounds => ExceptionCode::MemoryOutOfBounds,
+                            TrapCode::TableOutOfBounds => ExceptionCode::CallIndirectOOB,
+                            _ => {
+                                return Err(CallProtError(Box::new(
+                                    "unknown clif trap code".to_string(),
+                                )))
+                            }
                         },
-                        Ok(SIGSEGV) | Ok(SIGBUS) => WasmTrapInfo::MemoryOutOfBounds,
-                        Ok(SIGFPE) => WasmTrapInfo::IllegalArithmetic,
+                        Ok(SIGSEGV) | Ok(SIGBUS) => ExceptionCode::MemoryOutOfBounds,
+                        Ok(SIGFPE) => ExceptionCode::IllegalArithmetic,
                         _ => unimplemented!(
-                            "WasmTrapInfo::Unknown signal:{:?}",
+                            "ExceptionCode::Unknown signal:{:?}",
                             Signal::from_c_int(signum)
                         ),
-                    }))
+                    })))
                 } else {
                     let signal = match Signal::from_c_int(signum) {
                         Ok(SIGFPE) => "floating-point exception",
@@ -114,7 +118,7 @@ pub fn call_protected<T>(
                     };
                     // When the trap-handler is fully implemented, this will return more information.
                     let s = format!("unknown trap at {:p} - {}", faulting_addr, signal);
-                    Err(CallProtError::Error(Box::new(s)))
+                    Err(CallProtError(Box::new(s)))
                 }
             }
         } else {

lib/clif-backend/src/signal/windows.rs

@@ -8,7 +8,8 @@ use std::{
     ptr::{self, NonNull},
 };
 use wasmer_runtime_core::{
-    typed_func::{Trampoline, WasmTrapInfo},
+    backend::ExceptionCode,
+    typed_func::Trampoline,
     vm::{Ctx, Func},
 };
 use wasmer_win_exception_handler::CallProtectedData;
@@ -62,22 +63,26 @@ pub fn call_protected(
         srcloc: _,
     }) = handler_data.lookup(instruction_pointer as _)
     {
-        Err(CallProtError::Trap(match code as DWORD {
-            EXCEPTION_ACCESS_VIOLATION => WasmTrapInfo::MemoryOutOfBounds,
+        Err(CallProtError(Box::new(match code as DWORD {
+            EXCEPTION_ACCESS_VIOLATION => ExceptionCode::MemoryOutOfBounds,
             EXCEPTION_ILLEGAL_INSTRUCTION => match trapcode {
-                TrapCode::BadSignature => WasmTrapInfo::IncorrectCallIndirectSignature,
-                TrapCode::IndirectCallToNull => WasmTrapInfo::CallIndirectOOB,
-                TrapCode::HeapOutOfBounds => WasmTrapInfo::MemoryOutOfBounds,
-                TrapCode::TableOutOfBounds => WasmTrapInfo::CallIndirectOOB,
-                TrapCode::UnreachableCodeReached => WasmTrapInfo::Unreachable,
-                _ => WasmTrapInfo::Unknown,
+                TrapCode::BadSignature => ExceptionCode::IncorrectCallIndirectSignature,
+                TrapCode::IndirectCallToNull => ExceptionCode::CallIndirectOOB,
+                TrapCode::HeapOutOfBounds => ExceptionCode::MemoryOutOfBounds,
+                TrapCode::TableOutOfBounds => ExceptionCode::CallIndirectOOB,
+                TrapCode::UnreachableCodeReached => ExceptionCode::Unreachable,
+                _ => return Err(CallProtError(Box::new("unknown trap code".to_string()))),
             },
-            EXCEPTION_STACK_OVERFLOW => WasmTrapInfo::Unknown,
+            EXCEPTION_STACK_OVERFLOW => ExceptionCode::MemoryOutOfBounds,
             EXCEPTION_INT_DIVIDE_BY_ZERO | EXCEPTION_INT_OVERFLOW => {
-                WasmTrapInfo::IllegalArithmetic
+                ExceptionCode::IllegalArithmetic
             }
-            _ => WasmTrapInfo::Unknown,
-        }))
+            _ => {
+                return Err(CallProtError(Box::new(
+                    "unknown exception code".to_string(),
+                )))
+            }
+        })))
     } else {
         let signal = match code as DWORD {
             EXCEPTION_FLT_DENORMAL_OPERAND
@@ -110,7 +115,7 @@ pub fn call_protected(
             exception_address, code, signal,
         );
 
-        Err(CallProtError::Error(Box::new(s)))
+        Err(CallProtError(Box::new(s)))
     }
 }
 

lib/llvm-backend/src/backend.rs

@@ -30,7 +30,7 @@ use wasmer_runtime_core::{
     module::ModuleInfo,
     state::ModuleStateMap,
     structures::TypedIndex,
-    typed_func::{Trampoline, Wasm, WasmTrapInfo},
+    typed_func::{Trampoline, Wasm},
     types::{LocalFuncIndex, SigIndex},
     vm, vmcalls,
 };
@@ -65,8 +65,7 @@ extern "C" {
         func_ptr: NonNull<vm::Func>,
         params: *const u64,
         results: *mut u64,
-        trap_out: *mut WasmTrapInfo,
-        user_error: *mut Option<Box<dyn Any + Send>>,
+        error_out: *mut Option<Box<dyn Any + Send>>,
         invoke_env: Option<NonNull<c_void>>,
     ) -> bool;
 }

lib/middleware-common-tests/src/lib.rs

@@ -165,12 +165,10 @@ mod tests {
         }
 
         let err = result.unwrap_err();
-        match err {
-            RuntimeError::Error { data } => {
-                assert!(data.downcast_ref::<ExecutionLimitExceededError>().is_some());
-            }
-            _ => unreachable!(),
-        }
+        assert!(err
+            .0
+            .downcast_ref::<ExecutionLimitExceededError>()
+            .is_some());
 
         // verify it used the correct number of points
         assert_eq!(get_points_used(&instance), 109); // Used points will be slightly more than `limit` because of the way we do gas checking.

lib/runtime-core-tests/tests/imports.rs

@@ -16,12 +16,7 @@ macro_rules! call_and_assert {
                 expected_value,
                 concat!("Expected right when calling `", stringify!($function), "`.")
             ),
-            (
-                Err(RuntimeError::Error { data }),
-                Err(RuntimeError::Error {
-                    data: expected_data,
-                }),
-            ) => {
+            (Err(RuntimeError(data)), Err(RuntimeError(expected_data))) => {
                 if let (Some(data), Some(expected_data)) = (
                     data.downcast_ref::<&str>(),
                     expected_data.downcast_ref::<&str>(),
@@ -260,35 +255,25 @@ test!(
 test!(
     test_fn_trap,
     function_fn_trap,
-    Err(RuntimeError::Error {
-        data: Box::new(format!("foo {}", 2))
-    })
+    Err(RuntimeError(Box::new(format!("foo {}", 2))))
 );
 test!(
     test_closure_trap,
     function_closure_trap,
-    Err(RuntimeError::Error {
-        data: Box::new(format!("bar {}", 2))
-    })
+    Err(RuntimeError(Box::new(format!("bar {}", 2))))
 );
 test!(
     test_fn_trap_with_vmctx,
     function_fn_trap_with_vmctx,
-    Err(RuntimeError::Error {
-        data: Box::new(format!("baz {}", 2 + SHIFT))
-    })
+    Err(RuntimeError(Box::new(format!("baz {}", 2 + SHIFT))))
 );
 test!(
     test_closure_trap_with_vmctx,
     function_closure_trap_with_vmctx,
-    Err(RuntimeError::Error {
-        data: Box::new(format!("qux {}", 2 + SHIFT))
-    })
+    Err(RuntimeError(Box::new(format!("qux {}", 2 + SHIFT))))
 );
 test!(
     test_closure_trap_with_vmctx_and_env,
     function_closure_trap_with_vmctx_and_env,
-    Err(RuntimeError::Error {
-        data: Box::new(format!("! {}", 2 + shift + SHIFT))
-    })
+    Err(RuntimeError(Box::new(format!("! {}", 2 + shift + SHIFT))))
 );

lib/runtime-core/src/backend.rs

@@ -13,6 +13,7 @@ use crate::{
     module::ModuleInfo,
     sys::Memory,
 };
+use std::fmt;
 use std::{any::Any, ptr::NonNull};
 
 use std::collections::HashMap;
@@ -158,13 +159,36 @@ impl ExceptionTable {
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Serialize, Deserialize)]
 pub enum ExceptionCode {
     /// An `unreachable` opcode was executed.
-    Unreachable,
-
+    Unreachable = 0,
+    /// Call indirect incorrect signature trap.
+    IncorrectCallIndirectSignature = 1,
+    /// Memory out of bounds trap.
+    MemoryOutOfBounds = 2,
+    /// Call indirect out of bounds trap.
+    CallIndirectOOB = 3,
     /// An arithmetic exception, e.g. divided by zero.
-    Arithmetic,
+    IllegalArithmetic = 4,
+    /// Misaligned atomic access trap.
+    MisalignedAtomicAccess = 5,
+}
 
-    /// Memory access exception, e.g. misaligned/out-of-bound read/write.
-    Memory,
+impl fmt::Display for ExceptionCode {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                ExceptionCode::Unreachable => "unreachable",
+                ExceptionCode::IncorrectCallIndirectSignature => {
+                    "incorrect `call_indirect` signature"
+                }
+                ExceptionCode::MemoryOutOfBounds => "memory out-of-bounds access",
+                ExceptionCode::CallIndirectOOB => "`call_indirect` out-of-bounds",
+                ExceptionCode::IllegalArithmetic => "illegal arithmetic operation",
+                ExceptionCode::MisalignedAtomicAccess => "misaligned atomic access",
+            }
+        )
+    }
 }
 
 pub trait Compiler {

lib/runtime-core/src/error.rs

@@ -179,18 +179,7 @@ impl std::error::Error for LinkError {}
 /// The main way to do this is `Instance.call`.
 ///
 /// Comparing two `RuntimeError`s always evaluates to false.
-pub enum RuntimeError {
-    /// Trap.
-    Trap {
-        /// Trap message.
-        msg: Box<str>,
-    },
-    /// Error.
-    Error {
-        /// Error data.
-        data: Box<dyn Any + Send>,
-    },
-}
+pub struct RuntimeError(pub Box<dyn Any + Send>);
 
 impl PartialEq for RuntimeError {
     fn eq(&self, _other: &RuntimeError) -> bool {
@@ -200,21 +189,15 @@ impl PartialEq for RuntimeError {
 
 impl std::fmt::Display for RuntimeError {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        match self {
-            RuntimeError::Trap { ref msg } => {
-                write!(f, "WebAssembly trap occurred during runtime: {}", msg)
-            }
-            RuntimeError::Error { data } => {
-                if let Some(s) = data.downcast_ref::<String>() {
-                    write!(f, "\"{}\"", s)
-                } else if let Some(s) = data.downcast_ref::<&str>() {
-                    write!(f, "\"{}\"", s)
-                } else if let Some(exc_code) = data.downcast_ref::<ExceptionCode>() {
-                    write!(f, "Caught exception of type \"{:?}\".", exc_code)
-                } else {
-                    write!(f, "unknown error")
-                }
-            }
+        let data = &*self.0;
+        if let Some(s) = data.downcast_ref::<String>() {
+            write!(f, "\"{}\"", s)
+        } else if let Some(s) = data.downcast_ref::<&str>() {
+            write!(f, "\"{}\"", s)
+        } else if let Some(exc_code) = data.downcast_ref::<ExceptionCode>() {
+            write!(f, "Caught exception of type \"{:?}\".", exc_code)
+        } else {
+            write!(f, "unknown error")
         }
     }
 }