language-servers/roc
1
0
Fork 0
mirror of https://github.com/roc-lang/roc.git synced 2025-09-29 06:44:46 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 7

Implement long string literals

Browse source
This commit is contained in:
Brian Carroll 2021-11-04 20:44:29 +00:00
parent 414c9e6f86
commit c798c9d444
1 changed files with 31 additions and 19 deletions
Download patch file Download diff file Expand all files Collapse all files

50
compiler/gen_wasm/src/backend.rs
View file

@ -478,29 +478,41 @@ impl<'a> WasmBackend<'a> {
}; };
} }
StoredValue::StackMemory { location, size, .. } => match lit { StoredValue::StackMemory { location, .. } => match lit {
Literal::Str(s) => { Literal::Str(s) => {
// Small string is 8 bytes in Wasm // Load the stack memory address where we want to write
debug_assert!(*size == 8); let (local_id, offset) =
location.local_and_offset(self.storage.stack_frame_pointer);
self.code_builder.get_local(local_id);
self.code_builder.i32_const(offset as i32);
self.code_builder.i32_add();
// For either small or regular strings, we write 8 bytes to stack memory
let mut stack_mem_bytes = [0; 8];
let len = s.len(); let len = s.len();
if len < 8 { if len < 8 {
// A small string fits in an i64, so let's transform it to one. // Small string payload
let mut bytes = [0; 8]; stack_mem_bytes[0..len].clone_from_slice(s.as_bytes());
bytes[0..len].clone_from_slice(s.as_bytes()); // Small string flag and length
bytes[7] = 0x80 | (len as u8); stack_mem_bytes[7] = 0x80 | (len as u8);
let str_as_int = i64::from_le_bytes(bytes);
// Store it to the allocated stack memory location
let (local_id, offset) =
location.local_and_offset(self.storage.stack_frame_pointer);
self.code_builder.get_local(local_id);
self.code_builder.i32_const(offset as i32);
self.code_builder.i32_add();
self.code_builder.i64_const(str_as_int);
self.code_builder.i64_store(Align::Bytes4, offset);
} else { } else {
return not_supported_error(); // Store the bytes to the literals data segment
} let literal_bytes: &mut Vec<'a, u8> =
&mut self.module.data.segments[0].init;
literal_bytes.extend_from_slice(s.as_bytes());
// Calculate bytes for elements and length
let len32 = len as u32;
let elements_addr = self.next_literal_addr;
self.next_literal_addr += len32;
stack_mem_bytes[0..3].clone_from_slice(&elements_addr.to_le_bytes());
stack_mem_bytes[4..8].clone_from_slice(&len32.to_le_bytes());
};
self.code_builder
.i64_const(i64::from_le_bytes(stack_mem_bytes));
self.code_builder.i64_store(Align::Bytes4, offset);
} }
_ => { _ => {
return not_supported_error(); return not_supported_error();