language-servers/roc
1
0
Fork 0
mirror of https://github.com/roc-lang/roc.git synced 2025-10-01 15:51:12 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 6

Automatically clean up any unused values at the end of a block

Browse source
This commit is contained in:
Brian Carroll 2021-12-21 13:10:34 +00:00
parent 17dc6668ec
commit 2a141b3586
3 changed files with 20 additions and 20 deletions
Download patch file Download diff file Expand all files Collapse all files

36
compiler/gen_wasm/src/wasm_module/code_builder.rs
View file

@ -67,21 +67,11 @@ struct VmBlock<'a> {
opcode: OpCode,
/// the stack of values for this block
value_stack: Vec<'a, Symbol>,
/// whether this block pushes a result value to its parent
has_result: bool,
}
impl std::fmt::Debug for VmBlock<'_> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_fmt(format_args!(
"{:?} {}",
self.opcode,
if self.has_result {
"Result"
} else {
"NoResult"
}
))
f.write_fmt(format_args!("{:?}", self.opcode))
}
}
@ -193,7 +183,6 @@ impl<'a> CodeBuilder<'a> {
let mut vm_block_stack = Vec::with_capacity_in(8, arena);
let function_block = VmBlock {
opcode: BLOCK,
has_result: true,
value_stack: Vec::with_capacity_in(8, arena),
};
vm_block_stack.push(function_block);
@ -582,6 +571,11 @@ impl<'a> CodeBuilder<'a> {
/// Block instruction
fn inst_block(&mut self, opcode: OpCode, pops: usize, block_type: BlockType) {
if block_type != BlockType::NoResult {
// Returning from nested blocks is too complicated if we use result types
internal_error!("Block results are not supported.");
}
self.inst_base(opcode, pops, false);
self.code.push(block_type.as_byte());
@ -589,7 +583,6 @@ impl<'a> CodeBuilder<'a> {
self.vm_block_stack.push(VmBlock {
opcode,
value_stack: Vec::with_capacity_in(8, self.arena),
has_result: block_type != BlockType::NoResult,
});
log_instruction!(
@ -666,14 +659,21 @@ impl<'a> CodeBuilder<'a> {
}
pub fn end(&mut self) {
self.inst_base(END, 0, false);
// We need to drop any unused values from the VM stack in order to pass Wasm validation.
// This happens, for example, in test `gen_tags::if_guard_exhaustiveness`
let n_unused = self
.vm_block_stack
.last()
.map(|block| block.value_stack.len())
.unwrap_or(0);
let ended_block = self.vm_block_stack.pop().unwrap();
if ended_block.has_result {
let result = ended_block.value_stack.last().unwrap();
self.current_stack_mut().push(*result)
for _ in 0..n_unused {
self.drop_();
}
self.inst_base(END, 0, false);
self.vm_block_stack.pop();
log_instruction!("END \t\t{:?}", &self.vm_block_stack);
}
pub fn br(&mut self, levels: u32) {