1 //! Result and error types representing the outcome of compiling a function.
2 
3 use regalloc2::checker::CheckerErrors;
4 
5 use crate::verifier::VerifierErrors;
6 use std::string::String;
7 
8 /// A compilation error.
9 ///
10 /// When Cranelift fails to compile a function, it will return one of these error codes.
11 #[derive(Debug)]
12 pub enum CodegenError {
13     /// A list of IR verifier errors.
14     ///
15     /// This always represents a bug, either in the code that generated IR for Cranelift, or a bug
16     /// in Cranelift itself.
17     Verifier(VerifierErrors),
18 
19     /// An implementation limit was exceeded.
20     ///
21     /// Cranelift can compile very large and complicated functions, but the [implementation has
22     /// limits][limits] that cause compilation to fail when they are exceeded.
23     ///
24     /// [limits]: https://github.com/bytecodealliance/wasmtime/blob/main/cranelift/docs/ir.md#implementation-limits
25     ImplLimitExceeded,
26 
27     /// The code size for the function is too large.
28     ///
29     /// Different target ISAs may impose a limit on the size of a compiled function. If that limit
30     /// is exceeded, compilation fails.
31     CodeTooLarge,
32 
33     /// Something is not supported by the code generator. This might be an indication that a
34     /// feature is used without explicitly enabling it, or that something is temporarily
35     /// unsupported by a given target backend.
36     Unsupported(String),
37 
38     /// A failure to map Cranelift register representation to a DWARF register representation.
39     #[cfg(feature = "unwind")]
40     RegisterMappingError(crate::isa::unwind::systemv::RegisterMappingError),
41 
42     /// Register allocator internal error discovered by the symbolic checker.
43     Regalloc(CheckerErrors),
44 }
45 
46 /// A convenient alias for a `Result` that uses `CodegenError` as the error type.
47 pub type CodegenResult<T> = Result<T, CodegenError>;
48 
49 // This is manually implementing Error and Display instead of using thiserror to reduce the amount
50 // of dependencies used by Cranelift.
51 impl std::error::Error for CodegenError {
52     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
53         match self {
54             CodegenError::Verifier(source) => Some(source),
55             CodegenError::ImplLimitExceeded { .. }
56             | CodegenError::CodeTooLarge { .. }
57             | CodegenError::Unsupported { .. } => None,
58             #[cfg(feature = "unwind")]
59             CodegenError::RegisterMappingError { .. } => None,
60             CodegenError::Regalloc(..) => None,
61         }
62     }
63 }
64 
65 impl std::fmt::Display for CodegenError {
66     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
67         match self {
68             CodegenError::Verifier(_) => write!(f, "Verifier errors"),
69             CodegenError::ImplLimitExceeded => write!(f, "Implementation limit exceeded"),
70             CodegenError::CodeTooLarge => write!(f, "Code for function is too large"),
71             CodegenError::Unsupported(feature) => write!(f, "Unsupported feature: {}", feature),
72             #[cfg(feature = "unwind")]
73             CodegenError::RegisterMappingError(_0) => write!(f, "Register mapping error"),
74             CodegenError::Regalloc(errors) => write!(f, "Regalloc validation errors: {:?}", errors),
75         }
76     }
77 }
78 
79 impl From<VerifierErrors> for CodegenError {
80     fn from(source: VerifierErrors) -> Self {
81         CodegenError::Verifier { 0: source }
82     }
83 }
84