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Refactor CompiledModule to separate compile and linking stages (#1831)

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* Refactor how relocs are stored and handled

* refactor CompiledModule::instantiate and link_module

* Refactor DWARF creation: split generation and serialization

* Separate DWARF data transform from instantiation

* rm LinkContext
This commit is contained in:
Yury Delendik
2020-06-09 15:09:48 -05:00
committed by GitHub
parent ac87ed12bd
commit 4ebbcb82a9
9 changed files with 400 additions and 340 deletions
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39
crates/jit/src/link.rs
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@@ -1,8 +1,11 @@
//! Linking for JIT-compiled code.
use crate::Compilation;
use crate::CodeMemory;
use cranelift_codegen::binemit::Reloc;
use cranelift_codegen::ir::JumpTableOffsets;
use std::ptr::{read_unaligned, write_unaligned};
use wasmtime_environ::entity::PrimaryMap;
use wasmtime_environ::wasm::DefinedFuncIndex;
use wasmtime_environ::{Module, Relocation, RelocationTarget};
use wasmtime_runtime::libcalls;
use wasmtime_runtime::VMFunctionBody;
@@ -10,27 +13,22 @@ use wasmtime_runtime::VMFunctionBody;
/// Links a module that has been compiled with `compiled_module` in `wasmtime-environ`.
///
/// Performs all required relocations inside the function code, provided the necessary metadata.
pub fn link_module(module: &Module, compilation: &Compilation) {
for (i, function_relocs) in compilation.relocations.iter() {
for r in function_relocs.iter() {
let fatptr: *const [VMFunctionBody] = compilation.finished_functions[i];
let body = fatptr as *const VMFunctionBody;
apply_reloc(module, compilation, body, r);
}
}
for (i, function_relocs) in compilation.trampoline_relocations.iter() {
for r in function_relocs.iter() {
println!("tramopline relocation");
let body = compilation.trampolines[*i] as *const VMFunctionBody;
apply_reloc(module, compilation, body, r);
}
pub fn link_module(
code_memory: &mut CodeMemory,
module: &Module,
finished_functions: &PrimaryMap<DefinedFuncIndex, *mut [VMFunctionBody]>,
jt_offsets: &PrimaryMap<DefinedFuncIndex, JumpTableOffsets>,
) {
for (fatptr, r) in code_memory.unpublished_relocations() {
let body = fatptr as *const VMFunctionBody;
apply_reloc(module, finished_functions, jt_offsets, body, r);
}
}
fn apply_reloc(
module: &Module,
compilation: &Compilation,
finished_functions: &PrimaryMap<DefinedFuncIndex, *mut [VMFunctionBody]>,
jt_offsets: &PrimaryMap<DefinedFuncIndex, JumpTableOffsets>,
body: *const VMFunctionBody,
r: &Relocation,
) {
@@ -38,7 +36,7 @@ fn apply_reloc(
let target_func_address: usize = match r.reloc_target {
RelocationTarget::UserFunc(index) => match module.local.defined_func_index(index) {
Some(f) => {
let fatptr: *const [VMFunctionBody] = compilation.finished_functions[f];
let fatptr: *const [VMFunctionBody] = finished_functions[f];
fatptr as *const VMFunctionBody as usize
}
None => panic!("direct call to import"),
@@ -67,12 +65,11 @@ fn apply_reloc(
RelocationTarget::JumpTable(func_index, jt) => {
match module.local.defined_func_index(func_index) {
Some(f) => {
let offset = *compilation
.jt_offsets
let offset = *jt_offsets
.get(f)
.and_then(|ofs| ofs.get(jt))
.expect("func jump table");
let fatptr: *const [VMFunctionBody] = compilation.finished_functions[f];
let fatptr: *const [VMFunctionBody] = finished_functions[f];
fatptr as *const VMFunctionBody as usize + offset as usize
}
None => panic!("func index of jump table"),