SPIRV-Tools/source/opt/pass.h
Steven Perron 2e4563d94f
Document in the context what happens with id overflow. (#2159)
Added documentation to the ir context to indicates that TakeNextId()
returns 0 when the max id is reached.  TODOs were added to each call
sight so that we know where we have to start to handle this case.

Handle id overflow in |SplitLoopHeader|.

Handle id overflow in |GetOrCreatePreHeaderBlock|.

Handle failure to create preheader in LICM.

Part of https://github.com/KhronosGroup/SPIRV-Tools/issues/1841.
2018-12-06 09:07:00 -05:00

148 lines
5.1 KiB
C++

// Copyright (c) 2016 Google Inc.
//
// 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_OPT_PASS_H_
#define SOURCE_OPT_PASS_H_
#include <algorithm>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include "source/opt/basic_block.h"
#include "source/opt/def_use_manager.h"
#include "source/opt/ir_context.h"
#include "source/opt/module.h"
#include "spirv-tools/libspirv.hpp"
namespace spvtools {
namespace opt {
// Abstract class of a pass. All passes should implement this abstract class
// and all analysis and transformation is done via the Process() method.
class Pass {
public:
// The status of processing a module using a pass.
//
// The numbers for the cases are assigned to make sure that Failure & anything
// is Failure, SuccessWithChange & any success is SuccessWithChange.
enum class Status {
Failure = 0x00,
SuccessWithChange = 0x10,
SuccessWithoutChange = 0x11,
};
using ProcessFunction = std::function<bool(Function*)>;
// Destructs the pass.
virtual ~Pass() = default;
// Returns a descriptive name for this pass.
//
// NOTE: When deriving a new pass class, make sure you make the name
// compatible with the corresponding spirv-opt command-line flag. For example,
// if you add the flag --my-pass to spirv-opt, make this function return
// "my-pass" (no leading hyphens).
virtual const char* name() const = 0;
// Sets the message consumer to the given |consumer|. |consumer| which will be
// invoked every time there is a message to be communicated to the outside.
void SetMessageConsumer(MessageConsumer c) { consumer_ = std::move(c); }
// Returns the reference to the message consumer for this pass.
const MessageConsumer& consumer() const { return consumer_; }
// Returns the def-use manager used for this pass. TODO(dnovillo): This should
// be handled by the pass manager.
analysis::DefUseManager* get_def_use_mgr() const {
return context()->get_def_use_mgr();
}
analysis::DecorationManager* get_decoration_mgr() const {
return context()->get_decoration_mgr();
}
FeatureManager* get_feature_mgr() const {
return context()->get_feature_mgr();
}
// Returns a pointer to the current module for this pass.
Module* get_module() const { return context_->module(); }
// Sets the pointer to the current context for this pass.
void SetContextForTesting(IRContext* ctx) { context_ = ctx; }
// Returns a pointer to the current context for this pass.
IRContext* context() const { return context_; }
// Returns a pointer to the CFG for current module.
CFG* cfg() const { return context()->cfg(); }
// Run the pass on the given |module|. Returns Status::Failure if errors occur
// when processing. Returns the corresponding Status::Success if processing is
// successful to indicate whether changes are made to the module. If there
// were any changes it will also invalidate the analyses in the IRContext
// that are not preserved.
//
// It is an error if |Run| is called twice with the same instance of the pass.
// If this happens the return value will be |Failure|.
Status Run(IRContext* ctx);
// Returns the set of analyses that the pass is guaranteed to preserve.
virtual IRContext::Analysis GetPreservedAnalyses() {
return IRContext::kAnalysisNone;
}
// Return type id for |ptrInst|'s pointee
uint32_t GetPointeeTypeId(const Instruction* ptrInst) const;
protected:
// Constructs a new pass.
//
// The constructed instance will have an empty message consumer, which just
// ignores all messages from the library. Use SetMessageConsumer() to supply
// one if messages are of concern.
Pass();
// Processes the given |module|. Returns Status::Failure if errors occur when
// processing. Returns the corresponding Status::Success if processing is
// succesful to indicate whether changes are made to the module.
virtual Status Process() = 0;
// Return the next available SSA id and increment it.
// TODO(1841): Handle id overflow.
uint32_t TakeNextId() { return context_->TakeNextId(); }
private:
MessageConsumer consumer_; // Message consumer.
// The context that this pass belongs to.
IRContext* context_;
// An instance of a pass can only be run once because it is too hard to
// enforce proper resetting of internal state for each instance. This member
// is used to check that we do not run the same instance twice.
bool already_run_;
};
inline Pass::Status CombineStatus(Pass::Status a, Pass::Status b) {
return std::min(a, b);
}
} // namespace opt
} // namespace spvtools
#endif // SOURCE_OPT_PASS_H_