fergalmoran/ladybird
1
0
Fork 0
mirror of https://github.com/fergalmoran/ladybird.git synced 2025-12-22 09:19:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

LibJS: Don't generate useless jumps for if statement

Browse Source 
If statements without an else clause generated jumps to the next
instruction, this commit fixes the if statement generation so that it
dosen't produce them anymore.

This is an example of JS code that generates the useless jumps
(a => if(a){}) ();
This commit is contained in:
samu698
2024-10-26 15:18:47 +02:00
committed by Andreas Kling
parent 257ebea364
commit 7865fbfe6d
1 changed files with 9 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
View File

@@ -2330,7 +2330,8 @@ Bytecode::CodeGenerationErrorOr<Optional<ScopedOperand>> IfStatement::generate_b
auto& true_block = generator.make_block();
auto& false_block = generator.make_block();
auto& end_block = generator.make_block();
// NOTE: if there is no 'else' block the end block is the same as the false block
auto& end_block = m_alternate ? generator.make_block() : false_block;
Optional<ScopedOperand> completion;
if (generator.must_propagate_completion()) {
@@ -2347,26 +2348,20 @@ Bytecode::CodeGenerationErrorOr<Optional<ScopedOperand>> IfStatement::generate_b
generator.switch_to_basic_block(true_block);
auto consequent = TRY(m_consequent->generate_bytecode(generator, completion));
if (!generator.is_current_block_terminated()) {
if (generator.must_propagate_completion()) {
if (consequent.has_value())
if (generator.must_propagate_completion() && consequent.has_value())
generator.emit<Bytecode::Op::Mov>(*completion, *consequent);
}
generator.emit<Bytecode::Op::Jump>(Bytecode::Label { end_block });
}
generator.switch_to_basic_block(false_block);
Optional<ScopedOperand> alternate;
if (m_alternate) {
alternate = TRY(m_alternate->generate_bytecode(generator, completion));
}
generator.switch_to_basic_block(false_block);
auto alternate = TRY(m_alternate->generate_bytecode(generator, completion));
if (!generator.is_current_block_terminated()) {
if (generator.must_propagate_completion()) {
if (alternate.has_value())
if (generator.must_propagate_completion() && alternate.has_value())
generator.emit<Bytecode::Op::Mov>(*completion, *alternate);
}
generator.emit<Bytecode::Op::Jump>(Bytecode::Label { end_block });
}
}
generator.switch_to_basic_block(end_block);