| // Copyright (c) 2020 Google LLC |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "source/fuzz/transformation_function_call.h" |
| |
| #include "source/fuzz/call_graph.h" |
| #include "source/fuzz/fuzzer_util.h" |
| #include "source/fuzz/instruction_descriptor.h" |
| |
| namespace spvtools { |
| namespace fuzz { |
| |
| TransformationFunctionCall::TransformationFunctionCall( |
| protobufs::TransformationFunctionCall message) |
| : message_(std::move(message)) {} |
| |
| TransformationFunctionCall::TransformationFunctionCall( |
| uint32_t fresh_id, uint32_t callee_id, |
| const std::vector<uint32_t>& argument_id, |
| const protobufs::InstructionDescriptor& instruction_to_insert_before) { |
| message_.set_fresh_id(fresh_id); |
| message_.set_callee_id(callee_id); |
| for (auto argument : argument_id) { |
| message_.add_argument_id(argument); |
| } |
| *message_.mutable_instruction_to_insert_before() = |
| instruction_to_insert_before; |
| } |
| |
| bool TransformationFunctionCall::IsApplicable( |
| opt::IRContext* ir_context, |
| const TransformationContext& transformation_context) const { |
| // The result id must be fresh |
| if (!fuzzerutil::IsFreshId(ir_context, message_.fresh_id())) { |
| return false; |
| } |
| |
| // The function must exist |
| auto callee_inst = |
| ir_context->get_def_use_mgr()->GetDef(message_.callee_id()); |
| if (!callee_inst || callee_inst->opcode() != SpvOpFunction) { |
| return false; |
| } |
| |
| // The function must not be an entry point |
| if (fuzzerutil::FunctionIsEntryPoint(ir_context, message_.callee_id())) { |
| return false; |
| } |
| |
| auto callee_type_inst = ir_context->get_def_use_mgr()->GetDef( |
| callee_inst->GetSingleWordInOperand(1)); |
| assert(callee_type_inst->opcode() == SpvOpTypeFunction && |
| "Bad function type."); |
| |
| // The number of expected function arguments must match the number of given |
| // arguments. The number of expected arguments is one less than the function |
| // type's number of input operands, as one operand is for the return type. |
| if (callee_type_inst->NumInOperands() - 1 != |
| static_cast<uint32_t>(message_.argument_id().size())) { |
| return false; |
| } |
| |
| // The instruction descriptor must refer to a position where it is valid to |
| // insert the call |
| auto insert_before = |
| FindInstruction(message_.instruction_to_insert_before(), ir_context); |
| if (!insert_before) { |
| return false; |
| } |
| if (!fuzzerutil::CanInsertOpcodeBeforeInstruction(SpvOpFunctionCall, |
| insert_before)) { |
| return false; |
| } |
| |
| auto block = ir_context->get_instr_block(insert_before); |
| auto enclosing_function = block->GetParent(); |
| |
| // If the block is not dead, the function must be livesafe |
| bool block_is_dead = |
| transformation_context.GetFactManager()->BlockIsDead(block->id()); |
| if (!block_is_dead && |
| !transformation_context.GetFactManager()->FunctionIsLivesafe( |
| message_.callee_id())) { |
| return false; |
| } |
| |
| // The ids must all match and have the right types and satisfy rules on |
| // pointers. If the block is not dead, pointers must be arbitrary. |
| for (uint32_t arg_index = 0; |
| arg_index < static_cast<uint32_t>(message_.argument_id().size()); |
| arg_index++) { |
| opt::Instruction* arg_inst = |
| ir_context->get_def_use_mgr()->GetDef(message_.argument_id(arg_index)); |
| if (!arg_inst) { |
| // The given argument does not correspond to an instruction. |
| return false; |
| } |
| if (!arg_inst->type_id()) { |
| // The given argument does not have a type; it is thus not suitable. |
| } |
| if (arg_inst->type_id() != |
| callee_type_inst->GetSingleWordInOperand(arg_index + 1)) { |
| // Argument type mismatch. |
| return false; |
| } |
| opt::Instruction* arg_type_inst = |
| ir_context->get_def_use_mgr()->GetDef(arg_inst->type_id()); |
| if (arg_type_inst->opcode() == SpvOpTypePointer) { |
| switch (arg_inst->opcode()) { |
| case SpvOpFunctionParameter: |
| case SpvOpVariable: |
| // These are OK |
| break; |
| default: |
| // Other pointer ids cannot be passed as parameters |
| return false; |
| } |
| if (!block_is_dead && |
| !transformation_context.GetFactManager()->PointeeValueIsIrrelevant( |
| arg_inst->result_id())) { |
| // This is not a dead block, so pointer parameters passed to the called |
| // function might really have their contents modified. We thus require |
| // such pointers to be to arbitrary-valued variables, which this is not. |
| return false; |
| } |
| } |
| |
| // The argument id needs to be available (according to dominance rules) at |
| // the point where the call will occur. |
| if (!fuzzerutil::IdIsAvailableBeforeInstruction(ir_context, insert_before, |
| arg_inst->result_id())) { |
| return false; |
| } |
| } |
| |
| // Introducing the call must not lead to recursion. |
| if (message_.callee_id() == enclosing_function->result_id()) { |
| // This would be direct recursion. |
| return false; |
| } |
| // Ensure the call would not lead to indirect recursion. |
| return !CallGraph(ir_context) |
| .GetIndirectCallees(message_.callee_id()) |
| .count(block->GetParent()->result_id()); |
| } |
| |
| void TransformationFunctionCall::Apply( |
| opt::IRContext* ir_context, TransformationContext* /*unused*/) const { |
| // Update the module's bound to reflect the fresh id for the result of the |
| // function call. |
| fuzzerutil::UpdateModuleIdBound(ir_context, message_.fresh_id()); |
| // Get the return type of the function being called. |
| uint32_t return_type = |
| ir_context->get_def_use_mgr()->GetDef(message_.callee_id())->type_id(); |
| // Populate the operands to the call instruction, with the function id and the |
| // arguments. |
| opt::Instruction::OperandList operands; |
| operands.push_back({SPV_OPERAND_TYPE_ID, {message_.callee_id()}}); |
| for (auto arg : message_.argument_id()) { |
| operands.push_back({SPV_OPERAND_TYPE_ID, {arg}}); |
| } |
| // Insert the function call before the instruction specified in the message. |
| FindInstruction(message_.instruction_to_insert_before(), ir_context) |
| ->InsertBefore(MakeUnique<opt::Instruction>( |
| ir_context, SpvOpFunctionCall, return_type, message_.fresh_id(), |
| operands)); |
| // Invalidate all analyses since we have changed the module. |
| ir_context->InvalidateAnalysesExceptFor(opt::IRContext::kAnalysisNone); |
| } |
| |
| protobufs::Transformation TransformationFunctionCall::ToMessage() const { |
| protobufs::Transformation result; |
| *result.mutable_function_call() = message_; |
| return result; |
| } |
| |
| std::unordered_set<uint32_t> TransformationFunctionCall::GetFreshIds() const { |
| return {message_.fresh_id()}; |
| } |
| |
| } // namespace fuzz |
| } // namespace spvtools |
