爱特每羊队
58 lines
2.0 KiB
Rust
58 lines
2.0 KiB
Rust
use super::*;
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impl Compiler {
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fn emit_switch_statement(&self, stmt: &Statement, ctx: &mut CompileCtx) -> Result<Option<u8>, String> {
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let Statement::SwitchStatement(sw) = stmt else {
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return Ok(None);
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};
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let id = ctx.next_label_id();
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let end_label = Label::SwitchEnd(id);
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ctx.push_switch(end_label);
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let disc_reg = self.emit_expression(&sw.discriminant, ctx)?;
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let compare_reg_checkpoint = ctx.reg_checkpoint();
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let cases = &sw.cases;
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for (case_idx, case) in cases.iter().enumerate() {
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if let Some(test) = &case.test {
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let test_reg = self.emit_expression(test, ctx)?;
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let eq_reg = ctx.alloc_reg();
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ctx.emit(opcode::encode(OpCode::EQ, eq_reg, disc_reg, test_reg));
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let case_label = Label::SwitchCase(id, case_idx as u32);
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let body_pos = ctx.resolve_label(case_label)?;
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let offset = (body_pos as isize) - (ctx.bytecode.len() as isize);
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let offset = ctx.checked_jump_offset(offset);
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ctx.emit(opcode::encode_jmp_if_true(eq_reg, offset));
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ctx.restore_reg_checkpoint(compare_reg_checkpoint);
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}
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}
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let has_default = cases.iter().any(|c| c.test.is_none());
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if !has_default {
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let end_pos = ctx.resolve_label(end_label)?;
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let offset = (end_pos as isize) - (ctx.bytecode.len() as isize);
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let offset = ctx.checked_jump_offset(offset);
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ctx.emit(opcode::encode_jmp(offset));
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}
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for case in cases.iter() {
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for s in &case.consequent {
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self.emit_statement(s, ctx)?;
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}
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}
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ctx.pop_switch();
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Ok(None)
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}
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pub(in crate::emitter) fn emit_switch_domain(
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&self, stmt: &Statement, ctx: &mut CompileCtx,
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) -> Result<Option<u8>, String> {
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match stmt {
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Statement::SwitchStatement(_) => self.emit_switch_statement(stmt, ctx),
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_ => Ok(None),
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}
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}
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}
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