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// Copyright (c) 2019 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.
#ifndef SOURCE_FUZZ_TRANSFORMATION_ADD_FUNCTION_H_
#define SOURCE_FUZZ_TRANSFORMATION_ADD_FUNCTION_H_
#include "source/fuzz/protobufs/spirvfuzz_protobufs.h"
#include "source/fuzz/transformation.h"
#include "source/fuzz/transformation_context.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace fuzz {
class TransformationAddFunction : public Transformation {
public:
explicit TransformationAddFunction(
const protobufs::TransformationAddFunction& message);
// Creates a transformation to add a non live-safe function.
explicit TransformationAddFunction(
const std::vector<protobufs::Instruction>& instructions);
// Creates a transformation to add a live-safe function.
TransformationAddFunction(
const std::vector<protobufs::Instruction>& instructions,
uint32_t loop_limiter_variable_id, uint32_t loop_limit_constant_id,
const std::vector<protobufs::LoopLimiterInfo>& loop_limiters,
uint32_t kill_unreachable_return_value_id,
const std::vector<protobufs::AccessChainClampingInfo>&
access_chain_clampers);
// - |message_.instruction| must correspond to a sufficiently well-formed
// sequence of instructions that a function can be created from them
// - If |message_.is_livesafe| holds then |message_| must contain suitable
// ingredients to make the function livesafe, and the function must only
// invoke other livesafe functions
// - Adding the created function to the module must lead to a valid module.
bool IsApplicable(
opt::IRContext* ir_context,
const TransformationContext& transformation_context) const override;
// Adds the function defined by |message_.instruction| to the module, making
// it livesafe if |message_.is_livesafe| holds.
void Apply(opt::IRContext* ir_context,
TransformationContext* transformation_context) const override;
std::unordered_set<uint32_t> GetFreshIds() const override;
protobufs::Transformation ToMessage() const override;
// Helper method that, given composite type |composite_type_inst|, returns the
// type of the sub-object at index |index_id|, which is required to be in-
// bounds.
static opt::Instruction* FollowCompositeIndex(
opt::IRContext* ir_context, const opt::Instruction& composite_type_inst,
uint32_t index_id);
// Returns id of the back-edge block, given the corresponding
// |loop_header_block_id|. |loop_header_block_id| must be the id of a loop
// header block. Returns 0 if the loop has no back-edge block.
static uint32_t GetBackEdgeBlockId(opt::IRContext* ir_context,
uint32_t loop_header_block_id);
// Attempts to create a function from the series of instructions in
// |message_.instruction| and add it to |ir_context|.
//
// Returns false if adding the function is not possible due to the messages
// not respecting the basic structure of a function, e.g. if there is no
// OpFunction instruction or no blocks; in this case |ir_context| is left in
// an indeterminate state.
//
// Otherwise returns true. Whether |ir_context| is valid after addition of
// the function depends on the contents of |message_.instruction|.
//
// Intended usage:
// - Perform a dry run of this method on a clone of a module, and use
// the validator to check whether the resulting module is valid. Working
// on a clone means it does not matter if the function fails to be cleanly
// added, or leads to an invalid module.
// - If the dry run succeeds, run the method on the real module of interest,
// to add the function.
bool TryToAddFunction(opt::IRContext* ir_context) const;
private:
// Should only be called if |message_.is_livesafe| holds. Attempts to make
// the function livesafe (see FactFunctionIsLivesafe for a definition).
// Returns false if this is not possible, due to |message_| or |ir_context|
// not containing sufficient ingredients (such as types and fresh ids) to add
// the instrumentation necessary to make the function livesafe.
bool TryToMakeFunctionLivesafe(
opt::IRContext* ir_context,
const TransformationContext& transformation_context) const;
// A helper for TryToMakeFunctionLivesafe that tries to add loop-limiting
// logic.
bool TryToAddLoopLimiters(opt::IRContext* ir_context,
opt::Function* added_function) const;
// A helper for TryToMakeFunctionLivesafe that tries to replace OpKill and
// OpUnreachable instructions into return instructions.
bool TryToTurnKillOrUnreachableIntoReturn(
opt::IRContext* ir_context, opt::Function* added_function,
opt::Instruction* kill_or_unreachable_inst) const;
// A helper for TryToMakeFunctionLivesafe that tries to clamp access chain
// indices so that they are guaranteed to be in-bounds.
bool TryToClampAccessChainIndices(opt::IRContext* ir_context,
opt::Instruction* access_chain_inst) const;
protobufs::TransformationAddFunction message_;
};
} // namespace fuzz
} // namespace spvtools
#endif // SOURCE_FUZZ_TRANSFORMATION_ADD_FUNCTION_H_