ca1b461375
This begins reorganizing how translation and compilation occur, and setting up infrastructure for imports/exports and relocations. It splits parts out of StandaloneRuntime, forming Module, Compilation, and Instance structs, which can be used more independently. It also simplifies the command-line interface, in a step towards making simple tools that just expose the functionality of the libraries.
91 lines
2.9 KiB
Rust
91 lines
2.9 KiB
Rust
//! An `Instance` contains all the runtime state used by execution of a wasm
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//! module.
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use cretonne::ir;
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use cton_wasm::GlobalIndex;
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use module::Module;
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const PAGE_SIZE: usize = 65536;
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/// An Instance of a WebAssemby module.
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#[derive(Debug)]
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pub struct Instance {
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/// WebAssembly table data.
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pub tables: Vec<Vec<usize>>,
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/// WebAssembly linear memory data.
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pub memories: Vec<Vec<u8>>,
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/// WebAssembly global variable data.
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pub globals: Vec<u8>,
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}
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impl Instance {
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/// Create a new `Instance`.
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pub fn new(module: &Module) -> Self {
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let mut result = Self {
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tables: Vec::new(),
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memories: Vec::new(),
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globals: Vec::new(),
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};
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result.instantiate_tables(module);
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result.instantiate_memories(module);
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result.instantiate_globals(module);
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result
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}
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/// Allocate memory in `self` for just the tables of the current module,
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/// without any initializers applied yet.
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fn instantiate_tables(&mut self, module: &Module) {
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debug_assert!(self.tables.is_empty());
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self.tables.reserve(module.tables.len());
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for table in &module.tables {
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let len = table.size;
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let mut v = Vec::with_capacity(len);
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v.resize(len, 0);
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self.tables.push(v);
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}
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}
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/// Allocate memory in `instance` for just the memories of the current module,
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/// without any initializers applied yet.
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fn instantiate_memories(&mut self, module: &Module) {
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debug_assert!(self.memories.is_empty());
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// Allocate the underlying memory and initialize it to all zeros.
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self.memories.reserve(module.memories.len());
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for memory in &module.memories {
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let len = memory.pages_count * PAGE_SIZE;
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let mut v = Vec::with_capacity(len);
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v.resize(len, 0);
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self.memories.push(v);
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}
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}
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/// Allocate memory in `instance` for just the globals of the current module,
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/// without any initializers applied yet.
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fn instantiate_globals(&mut self, module: &Module) {
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debug_assert!(self.globals.is_empty());
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// Allocate the underlying memory and initialize it to all zeros.
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let globals_data_size = module.globals.len() * 8;
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self.globals.resize(globals_data_size, 0);
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}
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/// Returns a slice of the contents of allocated linear memory.
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pub fn inspect_memory(&self, memory_index: usize, address: usize, len: usize) -> &[u8] {
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&self.memories.get(memory_index).expect(
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format!(
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"no memory for index {}",
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memory_index
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).as_str(),
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)
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[address..address + len]
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}
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/// Shows the value of a global variable.
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pub fn inspect_global(&self, global_index: GlobalIndex, ty: ir::Type) -> &[u8] {
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let offset = global_index * 8;
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let len = ty.bytes() as usize;
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&self.globals[offset..offset + len]
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}
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}
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