mirror of
https://github.com/c64scene-ar/llvm-6502.git
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d5b48ca422
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1296 91177308-0d34-0410-b5e6-96231b3b80d8
109 lines
3.7 KiB
C++
109 lines
3.7 KiB
C++
//===- SwapStructContents.cpp - Swap structure elements around ---*- C++ -*--=//
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//
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// This pass does a simple transformation that swaps all of the elements of the
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// struct types in the program around.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/SwapStructContents.h"
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#include "llvm/Transforms/MutateStructTypes.h"
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#include "llvm/Analysis/FindUsedTypes.h"
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#include "llvm/Analysis/FindUnsafePointerTypes.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Assembly/Writer.h"
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// PruneTypes - Given a type Ty, make sure that neither it, or one of its
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// subtypes, occur in TypesToModify.
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//
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static void PruneTypes(const Type *Ty, set<const StructType*> &TypesToModify,
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set<const Type*> &ProcessedTypes) {
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if (ProcessedTypes.count(Ty)) return; // Already been checked
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ProcessedTypes.insert(Ty);
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// If the element is in TypesToModify, remove it now...
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if (const StructType *ST = dyn_cast<StructType>(Ty)) {
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TypesToModify.erase(ST); // This doesn't fail if the element isn't present
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cerr << "Unable to swap type: " << ST << endl;
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}
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// Remove all types that this type contains as well... do not remove types
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// that are referenced only through pointers, because we depend on the size of
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// the pointer, not on what the structure points to.
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//
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for (Type::subtype_iterator I = Ty->subtype_begin(), E = Ty->subtype_end();
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I != E; ++I) {
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if (!isa<PointerType>(*I))
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PruneTypes(*I, TypesToModify, ProcessedTypes);
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}
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}
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// doPassInitialization - This does all of the work of the pass
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//
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bool SwapStructContents::doPassInitialization(Module *M) {
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// We need to know which types to modify, and which types we CAN'T modify
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FindUsedTypes FUT/*(true)*/; // TODO: Do symbol tables as well
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FindUnsafePointerTypes FUPT;
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// Simutaneously find all of the types used, and all of the types that aren't
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// safe.
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//
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vector<Pass*> Analyses;
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Analyses.push_back(&FUT);
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Analyses.push_back(&FUPT);
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Pass::runAllPasses(M, Analyses); // Do analyses
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// Get the results out of the analyzers...
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const set<PointerType*> &UnsafePTys = FUPT.getUnsafeTypes();
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const set<const Type *> &UsedTypes = FUT.getTypes();
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// Combine the two sets, weeding out non structure types. Closures in C++
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// sure would be nice.
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set<const StructType*> TypesToModify;
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for (set<const Type *>::const_iterator I = UsedTypes.begin(),
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E = UsedTypes.end(); I != E; ++I)
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if (const StructType *ST = dyn_cast<StructType>(*I))
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TypesToModify.insert(ST);
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// Go through the Unsafe types and remove all types from TypesToModify that we
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// are not allowed to modify, because that would be unsafe.
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//
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set<const Type*> ProcessedTypes;
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for (set<PointerType*>::const_iterator I = UnsafePTys.begin(),
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E = UnsafePTys.end(); I != E; ++I) {
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cerr << "Pruning type: " << *I << endl;
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PruneTypes(*I, TypesToModify, ProcessedTypes);
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}
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// Build up a set of structure types that we are going to modify, and
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// information describing how to modify them.
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map<const StructType*, vector<int> > Transforms;
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for (set<const StructType*>::iterator I = TypesToModify.begin(),
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E = TypesToModify.end(); I != E; ++I) {
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const StructType *ST = *I;
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unsigned NumElements = ST->getElementTypes().size();
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vector<int> &Transform = Transforms[ST]; // Fill in the map directly
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Transform.reserve(NumElements);
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// The transformation to do is: just simply swap the elements
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for (unsigned i = 0; i < NumElements; ++i)
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Transform.push_back(NumElements-i-1);
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}
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// Create the Worker to do our stuff for us...
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StructMutator = new MutateStructTypes(Transforms);
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// Do initial work.
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return StructMutator->doPassInitialization(M);
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}
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