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LibWasm: Make blocks that take arguments actually work

Browse source 
Previously we were ignoring the actual parameters and setting the arity
to an incorrect value, which could cause crashes (or unexpected traps).
This commit is contained in:
Ali Mohammad Pur 2021-12-04 17:57:48 +03:30 • committed by Ali Mohammad Pur
commit fecbf0e03a
Notes: sideshowbarker 2024-07-17 22:32:33 +09:00
2 changed files with 52 additions and 8 deletions
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49
Userland/Libraries/LibWasm/AbstractMachine/BytecodeInterpreter.cpp
View file

@ -376,25 +376,60 @@ void BytecodeInterpreter::interpret(Configuration& configuration, InstructionPoi
return;
case Instructions::block.value(): {
size_t arity = 0;
size_t parameter_count = 0;
auto& args = instruction.arguments().get<Instruction::StructuredInstructionArgs>();
if (args.block_type.kind() != BlockType::Empty)
switch (args.block_type.kind()) {
case BlockType::Empty:
break;
case BlockType::Type:
arity = 1;
configuration.stack().push(Label(arity, args.end_ip));
break;
case BlockType::Index: {
auto& type = configuration.frame().module().types()[args.block_type.type_index().value()];
arity = type.results().size();
parameter_count = type.parameters().size();
}
}
configuration.stack().entries().insert(configuration.stack().size() - parameter_count, Label(arity, args.end_ip));
return;
}
case Instructions::loop.value(): {
size_t arity = 0;
size_t parameter_count = 0;
auto& args = instruction.arguments().get<Instruction::StructuredInstructionArgs>();
if (args.block_type.kind() != BlockType::Empty)
switch (args.block_type.kind()) {
case BlockType::Empty:
break;
case BlockType::Type:
arity = 1;
configuration.stack().push(Label(arity, ip.value() + 1));
break;
case BlockType::Index: {
auto& type = configuration.frame().module().types()[args.block_type.type_index().value()];
arity = type.results().size();
parameter_count = type.parameters().size();
}
}
configuration.stack().entries().insert(configuration.stack().size() - parameter_count, Label(arity, ip.value() + 1));
return;
}
case Instructions::if_.value(): {
size_t arity = 0;
size_t parameter_count = 0;
auto& args = instruction.arguments().get<Instruction::StructuredInstructionArgs>();
if (args.block_type.kind() != BlockType::Empty)
switch (args.block_type.kind()) {
case BlockType::Empty:
break;
case BlockType::Type:
arity = 1;
break;
case BlockType::Index: {
auto& type = configuration.frame().module().types()[args.block_type.type_index().value()];
arity = type.results().size();
parameter_count = type.parameters().size();
}
}
auto entry = configuration.stack().pop();
auto value = entry.get<Value>().to<i32>();
@ -402,12 +437,12 @@ void BytecodeInterpreter::interpret(Configuration& configuration, InstructionPoi
if (value.value() == 0) {
if (args.else_ip.has_value()) {
configuration.ip() = args.else_ip.value();
configuration.stack().push(move(end_label));
configuration.stack().entries().insert(configuration.stack().size() - parameter_count, end_label);
} else {
configuration.ip() = args.end_ip.value() + 1;
}
} else {
configuration.stack().push(move(end_label));
configuration.stack().entries().insert(configuration.stack().size() - parameter_count, end_label);
}
return;
}

11
Userland/Libraries/LibWasm/AbstractMachine/Validator.cpp
View file

@ -2424,11 +2424,14 @@ VALIDATE_INSTRUCTION(block)
if (stack.size() < parameters.size())
return Errors::invalid_stack_state();
for (size_t i = 0; i < parameters.size(); ++i) {
for (size_t i = 1; i <= parameters.size(); ++i) {
if (stack.take_last() != parameters[parameters.size() - i])
return Errors::invalid_stack_state();
}
for (auto& parameter : parameters)
stack.append(parameter);
m_entered_scopes.append(ChildScopeKind::Block);
m_block_details.empend(stack.actual_size(), Empty {});
m_parent_contexts.append(m_context);
@ -2451,6 +2454,9 @@ VALIDATE_INSTRUCTION(loop)
return Errors::invalid_stack_state();
}
for (auto& parameter : parameters)
stack.append(parameter);
m_entered_scopes.append(ChildScopeKind::Block);
m_block_details.empend(stack.actual_size(), Empty {});
m_parent_contexts.append(m_context);
@ -2476,6 +2482,9 @@ VALIDATE_INSTRUCTION(if_)
return Errors::invalid_stack_state();
}
for (auto& parameter : parameters)
stack.append(parameter);
m_entered_scopes.append(args.else_ip.has_value() ? ChildScopeKind::IfWithElse : ChildScopeKind::IfWithoutElse);
m_block_details.empend(stack.actual_size(), BlockDetails::IfDetails { stack, {} });
m_parent_contexts.append(m_context);