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//===- llvm/Pass.h - Base class for XForm Passes -----------------*- C++ -*--=//
//
// This file defines a base class that indicates that a specified class is a
// transformation pass implementation.
//
// Pass's are designed this way so that it is possible to run passes in a cache
// and organizationally optimal order without having to specify it at the front
// end. This allows arbitrary passes to be strung together and have them
// executed as effeciently as possible.
//
// Passes should extend one of the classes below, depending on the guarantees
// that it can make about what will be modified as it is run. For example, most
// global optimizations should derive from MethodPass, because they do not add
// or delete methods, they operate on the internals of the method.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_PASS_H
#define LLVM_PASS_H
#include "llvm/Module.h"
#include "llvm/Method.h"
class MethodPassBatcher;
//===----------------------------------------------------------------------===//
// Pass interface - Implemented by all 'passes'. Subclass this if you are an
// interprocedural optimization or you do not fit into any of the more
// constrained passes described below.
//
struct Pass {
// Destructor - Virtual so we can be subclassed
inline virtual ~Pass() {}
virtual bool run(Module *M) = 0;
};
//===----------------------------------------------------------------------===//
// MethodPass class - This class is used to implement most global optimizations.
// Optimizations should subclass this class if they meet the following
// constraints:
// 1. Optimizations are organized globally, ie a method at a time
// 2. Optimizing a method does not cause the addition or removal of any methods
// in the module
//
struct MethodPass : public Pass {
// doInitialization - Virtual method overridden by subclasses to do
// any neccesary per-module initialization.
//
virtual bool doInitialization(Module *M) { return false; }
// runOnMethod - Virtual method overriden by subclasses to do the per-method
// processing of the pass.
//
virtual bool runOnMethod(Method *M) = 0;
// doFinalization - Virtual method overriden by subclasses to do any post
// processing needed after all passes have run.
//
virtual bool doFinalization(Module *M) { return false; }
virtual bool run(Module *M) {
bool Changed = doInitialization(M);
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
Changed |= runOnMethod(*I);
return Changed | doFinalization(M);
}
bool run(Method *M) {
return doInitialization(M->getParent()) | runOnMethod(M)
| doFinalization(M->getParent());
}
};
//===----------------------------------------------------------------------===//
// CFGSafeMethodPass class - This class is used to implement global
// optimizations that do not modify the CFG of a method. Optimizations should
// subclass this class if they meet the following constraints:
// 1. Optimizations are global, operating on a method at a time.
// 2. Optimizations do not modify the CFG of the contained method, by adding,
// removing, or changing the order of basic blocks in a method.
// 3. Optimizations conform to all of the contstraints of MethodPass's.
//
struct CFGSafeMethodPass : public MethodPass {
// TODO: Differentiation from MethodPass will come later
};
//===----------------------------------------------------------------------===//
// BasicBlockPass class - This class is used to implement most local
// optimizations. Optimizations should subclass this class if they
// meet the following constraints:
// 1. Optimizations are local, operating on either a basic block or
// instruction at a time.
// 2. Optimizations do not modify the CFG of the contained method, or any
// other basic block in the method.
// 3. Optimizations conform to all of the contstraints of CFGSafeMethodPass's.
//
struct BasicBlockPass : public CFGSafeMethodPass {
// runOnBasicBlock - Virtual method overriden by subclasses to do the
// per-basicblock processing of the pass.
//
virtual bool runOnBasicBlock(BasicBlock *M) = 0;
virtual bool runOnMethod(Method *M) {
bool Changed = false;
for (Method::iterator I = M->begin(), E = M->end(); I != E; ++I)
Changed |= runOnBasicBlock(*I);
return Changed;
}
bool run(BasicBlock *BB) {
Module *M = BB->getParent()->getParent();
return doInitialization(M) | runOnBasicBlock(BB) | doFinalization(M);
}
};
//===----------------------------------------------------------------------===//
// PassManager - Container object for passes. The PassManager destructor
// deletes all passes contained inside of the PassManager, so you shouldn't
// delete passes manually, and all passes should be dynamically allocated.
//
class PassManager {
std::vector<Pass*> Passes;
MethodPassBatcher *Batcher;
public:
PassManager() : Batcher(0) {}
~PassManager();
// run - Run all of the queued passes on the specified module in an optimal
// way.
bool run(Module *M);
// add - Add a pass to the queue of passes to run. This passes ownership of
// the Pass to the PassManager. When the PassManager is destroyed, the pass
// will be destroyed as well, so there is no need to delete the pass. Also,
// all passes MUST be new'd.
//
void add(Pass *P);
void add(MethodPass *P);
void add(BasicBlockPass *P);
};
#endif
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