Files
wasmtime/lib/environ/src/compilation.rs
Dan Gohman 548c45c604 Rename wasmtime-runtime to wasmtime-environ.
This mirrors changes in cranelift.
2018-08-03 15:20:19 -07:00

128 lines
3.9 KiB
Rust

//! A `Compilation` contains the compiled function bodies for a WebAssembly
//! module.
use cranelift_codegen::binemit;
use cranelift_codegen::ir;
use cranelift_codegen::ir::ExternalName;
use cranelift_codegen::isa;
use cranelift_codegen::Context;
use cranelift_wasm::{FuncTranslator, FunctionIndex};
use environ::{get_func_name, ModuleTranslation};
/// The result of compiling a WebAssemby module's functions.
#[derive(Debug)]
pub struct Compilation {
/// Compiled machine code for the function bodies.
pub functions: Vec<Vec<u8>>,
}
impl Compilation {
/// Allocates the compilation result with the given function bodies.
pub fn new(functions: Vec<Vec<u8>>) -> Self {
Self { functions }
}
}
/// Implementation of a relocation sink that just saves all the information for later
pub struct RelocSink {
/// Relocations recorded for the function.
pub func_relocs: Vec<Relocation>,
}
impl binemit::RelocSink for RelocSink {
fn reloc_ebb(
&mut self,
_offset: binemit::CodeOffset,
_reloc: binemit::Reloc,
_ebb_offset: binemit::CodeOffset,
) {
// This should use the `offsets` field of `ir::Function`.
panic!("ebb headers not yet implemented");
}
fn reloc_external(
&mut self,
offset: binemit::CodeOffset,
reloc: binemit::Reloc,
name: &ExternalName,
addend: binemit::Addend,
) {
// FIXME: Handle grow_memory/current_memory.
let func_index = if let ExternalName::User { namespace, index } = *name {
debug_assert!(namespace == 0);
index
} else {
panic!("unrecognized external name")
} as usize;
self.func_relocs.push(Relocation {
reloc,
func_index,
offset,
addend,
});
}
fn reloc_jt(
&mut self,
_offset: binemit::CodeOffset,
_reloc: binemit::Reloc,
_jt: ir::JumpTable,
) {
panic!("jump tables not yet implemented");
}
}
impl RelocSink {
fn new() -> Self {
Self {
func_relocs: Vec::new(),
}
}
}
/// A record of a relocation to perform.
#[derive(Debug)]
pub struct Relocation {
/// The relocation code.
pub reloc: binemit::Reloc,
/// The function index.
pub func_index: FunctionIndex,
/// The offset where to apply the relocation.
pub offset: binemit::CodeOffset,
/// The addend to add to the relocation value.
pub addend: binemit::Addend,
}
/// Relocations to apply to function bodies.
pub type Relocations = Vec<Vec<Relocation>>;
/// Compile the module, producing a compilation result with associated
/// relocations.
pub fn compile_module<'data, 'module>(
translation: &ModuleTranslation<'data, 'module>,
isa: &isa::TargetIsa,
) -> Result<(Compilation, Relocations), String> {
let mut functions = Vec::new();
let mut relocations = Vec::new();
for (i, input) in translation.lazy.function_body_inputs.iter().enumerate() {
let func_index = i + translation.module.imported_funcs.len();
let mut context = Context::new();
context.func.name = get_func_name(func_index);
context.func.signature =
translation.module.signatures[translation.module.functions[func_index]].clone();
let mut trans = FuncTranslator::new();
trans
.translate(input, &mut context.func, &mut translation.func_env())
.map_err(|e| e.to_string())?;
let mut code_buf: Vec<u8> = Vec::new();
let mut reloc_sink = RelocSink::new();
let mut trap_sink = binemit::NullTrapSink {};
context
.compile_and_emit(isa, &mut code_buf, &mut reloc_sink, &mut trap_sink)
.map_err(|e| e.to_string())?;
functions.push(code_buf);
relocations.push(reloc_sink.func_relocs);
}
Ok((Compilation::new(functions), relocations))
}