Files
wasmtime/crates/obj/src/module.rs
Yury Delendik e5b81bbc28 Migrating code to object (from faerie) (#1848)
* Using the "object" library everywhere in wasmtime.
* scroll_derive
2020-06-10 11:27:00 -05:00

82 lines
2.6 KiB
Rust

use crate::context::layout_vmcontext;
use crate::data_segment::{declare_data_segment, emit_data_segment};
use crate::function::{declare_functions, emit_functions};
use crate::table::{declare_table, emit_table};
use anyhow::Result;
use object::write::{Object, Relocation, StandardSection, Symbol, SymbolSection};
use object::{RelocationEncoding, RelocationKind, SymbolFlags, SymbolKind, SymbolScope};
use wasmtime_environ::isa::TargetFrontendConfig;
use wasmtime_environ::{Compilation, DataInitializer, Module, Relocations};
fn emit_vmcontext_init(
obj: &mut Object,
module: &Module,
target_config: &TargetFrontendConfig,
) -> Result<()> {
let (data, table_relocs) = layout_vmcontext(module, target_config);
let symbol_id = obj.add_symbol(Symbol {
name: "_vmcontext_init".as_bytes().to_vec(),
value: 0,
size: 0,
kind: SymbolKind::Data,
scope: SymbolScope::Linkage,
weak: false,
section: SymbolSection::Undefined,
flags: SymbolFlags::None,
});
let section_id = obj.section_id(StandardSection::Data);
let section_offset = obj.add_symbol_data(symbol_id, section_id, &data, 1);
for reloc in table_relocs.iter() {
let target_name = format!("_table_{}", reloc.index);
let target_symbol = obj.symbol_id(target_name.as_bytes()).unwrap();
obj.add_relocation(
section_id,
Relocation {
offset: section_offset + reloc.offset as u64,
size: 64, // FIXME for all targets
kind: RelocationKind::Absolute,
encoding: RelocationEncoding::Generic,
symbol: target_symbol,
addend: 0,
},
)?;
}
Ok(())
}
/// Emits a module that has been emitted with the `wasmtime-environ` environment
/// implementation to a native object file.
pub fn emit_module(
obj: &mut Object,
module: &Module,
compilation: &Compilation,
relocations: &Relocations,
data_initializers: &[DataInitializer],
target_config: &TargetFrontendConfig,
) -> Result<()> {
declare_functions(obj, module, relocations)?;
for (i, initializer) in data_initializers.iter().enumerate() {
declare_data_segment(obj, initializer, i)?;
}
for i in 0..module.local.table_plans.len() {
declare_table(obj, i)?;
}
emit_functions(obj, module, compilation, relocations)?;
for (i, initializer) in data_initializers.iter().enumerate() {
emit_data_segment(obj, initializer, i)?;
}
for i in 0..module.local.table_plans.len() {
emit_table(obj, i)?;
}
emit_vmcontext_init(obj, module, target_config)?;
Ok(())
}