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* Fix a problem setting a name on a constant value that died because no symbol table was passed in * Add some comments describing the passes * Implement a new peephole: // Peephole optimize the following instructions: // %t = cast <T1>* %P to <T2> * ;; If T1 is losslessly convertable to T2 // store <T2> %V, <T2>* %t // // Into: // %t = cast <T2> %V to <T1> // store <T1> %t2, <T1>* %P git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1080 91177308-0d34-0410-b5e6-96231b3b80d8
683 lines
25 KiB
C++
683 lines
25 KiB
C++
//===- LevelRaise.cpp - Code to change LLVM to higher level -----------------=//
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//
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// This file implements the 'raising' part of the LevelChange API. This is
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// useful because, in general, it makes the LLVM code terser and easier to
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// analyze. Note that it is good to run DCE after doing this transformation.
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//
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// Eliminate silly things in the source that do not effect the level, but do
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// clean up the code:
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// * Casts of casts
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// - getelementptr/load & getelementptr/store are folded into a direct
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// load or store
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// - Convert this code (for both alloca and malloc):
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// %reg110 = shl uint %n, ubyte 2 ;;<uint>
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// %reg108 = alloca ubyte, uint %reg110 ;;<ubyte*>
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// %cast76 = cast ubyte* %reg108 to uint* ;;<uint*>
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// To: %cast76 = alloca uint, uint %n
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// Convert explicit addressing to use getelementptr instruction where possible
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// - ...
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//
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// Convert explicit addressing on pointers to use getelementptr instruction.
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// - If a pointer is used by arithmetic operation, insert an array casted
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// version into the source program, only for the following pointer types:
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// * Method argument pointers
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// - Pointers returned by alloca or malloc
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// - Pointers returned by function calls
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// - If a pointer is indexed with a value scaled by a constant size equal
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// to the element size of the array, the expression is replaced with a
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// getelementptr instruction.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/LevelChange.h"
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#include "llvm/Method.h"
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#include "llvm/Support/STLExtras.h"
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#include "llvm/iOther.h"
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#include "llvm/iMemory.h"
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#include "llvm/ConstPoolVals.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Optimizations/ConstantHandling.h"
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#include <map>
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#include <algorithm>
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#include "llvm/Assembly/Writer.h"
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//#define DEBUG_PEEPHOLE_INSTS 1
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#ifdef DEBUG_PEEPHOLE_INSTS
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#define PRINT_PEEPHOLE(ID, NUM, I) \
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cerr << "Inst P/H " << ID << "[" << NUM << "] " << I;
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#else
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#define PRINT_PEEPHOLE(ID, NUM, I)
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#endif
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#define PRINT_PEEPHOLE1(ID, I1) do { PRINT_PEEPHOLE(ID, 0, I1); } while (0)
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#define PRINT_PEEPHOLE2(ID, I1, I2) \
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do { PRINT_PEEPHOLE(ID, 0, I1); PRINT_PEEPHOLE(ID, 1, I2); } while (0)
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#define PRINT_PEEPHOLE3(ID, I1, I2, I3) \
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do { PRINT_PEEPHOLE(ID, 0, I1); PRINT_PEEPHOLE(ID, 1, I2); \
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PRINT_PEEPHOLE(ID, 2, I3); } while (0)
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// TargetData Hack: Eventually we will have annotations given to us by the
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// backend so that we know stuff about type size and alignments. For now
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// though, just use this, because it happens to match the model that GCC uses.
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//
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const TargetData TD("LevelRaise: Should be GCC though!");
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// losslessCastableTypes - Return true if the types are bitwise equivalent.
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// This predicate returns true if it is possible to cast from one type to
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// another without gaining or losing precision, or altering the bits in any way.
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//
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static bool losslessCastableTypes(const Type *T1, const Type *T2) {
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if (!T1->isPrimitiveType() && !isa<PointerType>(T1)) return false;
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if (!T2->isPrimitiveType() && !isa<PointerType>(T2)) return false;
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if (T1->getPrimitiveID() == T2->getPrimitiveID())
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return true; // Handles identity cast, and cast of differing pointer types
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// Now we know that they are two differing primitive or pointer types
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switch (T1->getPrimitiveID()) {
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case Type::UByteTyID: return T2 == Type::SByteTy;
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case Type::SByteTyID: return T2 == Type::UByteTy;
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case Type::UShortTyID: return T2 == Type::ShortTy;
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case Type::ShortTyID: return T2 == Type::UShortTy;
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case Type::UIntTyID: return T2 == Type::IntTy;
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case Type::IntTyID: return T2 == Type::UIntTy;
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case Type::ULongTyID:
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case Type::LongTyID:
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case Type::PointerTyID:
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return T2 == Type::ULongTy || T2 == Type::LongTy ||
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T2->getPrimitiveID() == Type::PointerTyID;
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default:
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return false; // Other types have no identity values
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}
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}
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// isReinterpretingCast - Return true if the cast instruction specified will
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// cause the operand to be "reinterpreted". A value is reinterpreted if the
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// cast instruction would cause the underlying bits to change.
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//
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static inline bool isReinterpretingCast(const CastInst *CI) {
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return !losslessCastableTypes(CI->getOperand(0)->getType(), CI->getType());
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}
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// getPointedToStruct - If the argument is a pointer type, and the pointed to
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// value is a struct type, return the struct type, else return null.
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//
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static const StructType *getPointedToStruct(const Type *Ty) {
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const PointerType *PT = dyn_cast<PointerType>(Ty);
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return PT ? dyn_cast<StructType>(PT->getValueType()) : 0;
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}
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// getStructOffsetType - Return a vector of offsets that are to be used to index
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// into the specified struct type to get as close as possible to index as we
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// can. Note that it is possible that we cannot get exactly to Offset, in which
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// case we update offset to be the offset we actually obtained. The resultant
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// leaf type is returned.
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//
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static const Type *getStructOffsetType(const Type *Ty, unsigned &Offset,
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vector<ConstPoolVal*> &Offsets) {
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if (!isa<StructType>(Ty)) {
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Offset = 0; // Return the offset that we were able to acheive
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return Ty; // Return the leaf type
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}
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assert(Offset < TD.getTypeSize(Ty) && "Offset not in struct!");
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const StructType *STy = cast<StructType>(Ty);
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const StructLayout *SL = TD.getStructLayout(STy);
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// This loop terminates always on a 0 <= i < MemberOffsets.size()
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unsigned i;
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for (i = 0; i < SL->MemberOffsets.size()-1; ++i)
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if (Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1])
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break;
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assert(Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1]);
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// Make sure to save the current index...
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Offsets.push_back(ConstPoolUInt::get(Type::UByteTy, i));
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unsigned SubOffs = Offset - SL->MemberOffsets[i];
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const Type *LeafTy = getStructOffsetType(STy->getElementTypes()[i], SubOffs,
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Offsets);
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Offset = SL->MemberOffsets[i] + SubOffs;
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return LeafTy;
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}
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// ReplaceInstWithValue - Replace all uses of an instruction (specified by BI)
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// with a value, then remove and delete the original instruction.
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//
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static void ReplaceInstWithValue(BasicBlock::InstListType &BIL,
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BasicBlock::iterator &BI, Value *V) {
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Instruction *I = *BI;
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// Replaces all of the uses of the instruction with uses of the value
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I->replaceAllUsesWith(V);
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// Remove the unneccesary instruction now...
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BIL.remove(BI);
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// Make sure to propogate a name if there is one already...
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if (I->hasName() && !V->hasName())
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V->setName(I->getName(), BIL.getParent()->getSymbolTable());
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// Remove the dead instruction now...
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delete I;
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}
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// ReplaceInstWithInst - Replace the instruction specified by BI with the
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// instruction specified by I. The original instruction is deleted and BI is
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// updated to point to the new instruction.
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//
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static void ReplaceInstWithInst(BasicBlock::InstListType &BIL,
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BasicBlock::iterator &BI, Instruction *I) {
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assert(I->getParent() == 0 &&
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"ReplaceInstWithInst: Instruction already inserted into basic block!");
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// Insert the new instruction into the basic block...
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BI = BIL.insert(BI, I)+1;
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// Replace all uses of the old instruction, and delete it.
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ReplaceInstWithValue(BIL, BI, I);
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// Reexamine the instruction just inserted next time around the cleanup pass
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// loop.
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--BI;
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}
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// ExpressionConvertableToType - Return true if it is possible
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static bool ExpressionConvertableToType(Value *V, const Type *Ty) {
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Instruction *I = dyn_cast<Instruction>(V);
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if (I == 0) {
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// It's not an instruction, check to see if it's a constant... all constants
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// can be converted to an equivalent value (except pointers, they can't be
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// const prop'd in general).
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//
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if (isa<ConstPoolVal>(V) &&
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!isa<PointerType>(V->getType()) && !isa<PointerType>(Ty)) return true;
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return false; // Otherwise, we can't convert!
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}
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if (I->getType() == Ty) return false; // Expression already correct type!
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switch (I->getOpcode()) {
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case Instruction::Cast:
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// We can convert the expr if the cast destination type is losslessly
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// convertable to the requested type.
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return losslessCastableTypes(Ty, I->getType());
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case Instruction::Add:
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case Instruction::Sub:
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return ExpressionConvertableToType(I->getOperand(0), Ty) &&
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ExpressionConvertableToType(I->getOperand(1), Ty);
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case Instruction::Shl:
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case Instruction::Shr:
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return ExpressionConvertableToType(I->getOperand(0), Ty);
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}
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return false;
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}
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static Value *ConvertExpressionToType(Value *V, const Type *Ty) {
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assert(ExpressionConvertableToType(V, Ty) && "Value is not convertable!");
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Instruction *I = dyn_cast<Instruction>(V);
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if (I == 0)
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if (ConstPoolVal *CPV = cast<ConstPoolVal>(V)) {
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// Constants are converted by constant folding the cast that is required.
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// We assume here that all casts are implemented for constant prop.
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Value *Result = opt::ConstantFoldCastInstruction(CPV, Ty);
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if (!Result) cerr << "Couldn't fold " << CPV << " to " << Ty << endl;
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assert(Result && "ConstantFoldCastInstruction Failed!!!");
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return Result;
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}
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BasicBlock *BB = I->getParent();
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BasicBlock::InstListType &BIL = BB->getInstList();
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string Name = I->getName(); if (!Name.empty()) I->setName("");
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Instruction *Res; // Result of conversion
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//cerr << endl << endl << "Type:\t" << Ty << "\nInst: " << I << "BB Before: " << BB << endl;
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switch (I->getOpcode()) {
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case Instruction::Cast:
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Res = new CastInst(I->getOperand(0), Ty, Name);
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break;
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case Instruction::Add:
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case Instruction::Sub:
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Res = BinaryOperator::create(cast<BinaryOperator>(I)->getOpcode(),
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ConvertExpressionToType(I->getOperand(0), Ty),
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ConvertExpressionToType(I->getOperand(1), Ty),
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Name);
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break;
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case Instruction::Shl:
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case Instruction::Shr:
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Res = new ShiftInst(cast<ShiftInst>(I)->getOpcode(),
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ConvertExpressionToType(I->getOperand(0), Ty),
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I->getOperand(1), Name);
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break;
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default:
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assert(0 && "Expression convertable, but don't know how to convert?");
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return 0;
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}
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BasicBlock::iterator It = find(BIL.begin(), BIL.end(), I);
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assert(It != BIL.end() && "Instruction not in own basic block??");
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BIL.insert(It, Res);
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//cerr << "RInst: " << Res << "BB After: " << BB << endl << endl;
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return Res;
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}
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// DoInsertArrayCast - If the argument value has a pointer type, and if the
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// argument value is used as an array, insert a cast before the specified
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// basic block iterator that casts the value to an array pointer. Return the
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// new cast instruction (in the CastResult var), or null if no cast is inserted.
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//
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static bool DoInsertArrayCast(Method *CurMeth, Value *V, BasicBlock *BB,
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BasicBlock::iterator &InsertBefore,
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CastInst *&CastResult) {
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const PointerType *ThePtrType = dyn_cast<PointerType>(V->getType());
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if (!ThePtrType) return false;
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bool InsertCast = false;
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for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
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Instruction *Inst = cast<Instruction>(*I);
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switch (Inst->getOpcode()) {
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default: break; // Not an interesting use...
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case Instruction::Add: // It's being used as an array index!
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//case Instruction::Sub:
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InsertCast = true;
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break;
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case Instruction::Cast: // There is already a cast instruction!
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if (const PointerType *PT = dyn_cast<const PointerType>(Inst->getType()))
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if (const ArrayType *AT = dyn_cast<const ArrayType>(PT->getValueType()))
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if (AT->getElementType() == ThePtrType->getValueType()) {
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// Cast already exists! Return the existing one!
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CastResult = cast<CastInst>(Inst);
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return false; // No changes made to program though...
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}
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break;
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}
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}
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if (!InsertCast) return false; // There is no reason to insert a cast!
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// Insert a cast!
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const Type *ElTy = ThePtrType->getValueType();
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const PointerType *DestTy = PointerType::get(ArrayType::get(ElTy));
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CastResult = new CastInst(V, DestTy);
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BB->getInstList().insert(InsertBefore, CastResult);
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//cerr << "Inserted cast: " << CastResult;
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return true; // Made a change!
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}
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// DoInsertArrayCasts - Loop over all "incoming" values in the specified method,
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// inserting a cast for pointer values that are used as arrays. For our
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// purposes, an incoming value is considered to be either a value that is
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// either a method parameter, a value created by alloca or malloc, or a value
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// returned from a function call. All casts are kept attached to their original
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// values through the PtrCasts map.
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//
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static bool DoInsertArrayCasts(Method *M, map<Value*, CastInst*> &PtrCasts) {
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assert(!M->isExternal() && "Can't handle external methods!");
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// Insert casts for all arguments to the function...
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bool Changed = false;
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BasicBlock *CurBB = M->front();
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BasicBlock::iterator It = CurBB->begin();
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for (Method::ArgumentListType::iterator AI = M->getArgumentList().begin(),
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AE = M->getArgumentList().end(); AI != AE; ++AI) {
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CastInst *TheCast = 0;
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if (DoInsertArrayCast(M, *AI, CurBB, It, TheCast)) {
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It = CurBB->begin(); // We might have just invalidated the iterator!
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Changed = true; // Yes we made a change
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++It; // Insert next cast AFTER this one...
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}
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if (TheCast) // Is there a cast associated with this value?
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PtrCasts[*AI] = TheCast; // Yes, add it to the map...
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}
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// TODO: insert casts for alloca, malloc, and function call results. Also,
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// look for pointers that already have casts, to add to the map.
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return Changed;
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}
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// DoElminatePointerArithmetic - Loop over each incoming pointer variable,
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// replacing indexing arithmetic with getelementptr calls.
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//
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static bool DoEliminatePointerArithmetic(const pair<Value*, CastInst*> &Val) {
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Value *V = Val.first; // The original pointer
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CastInst *CV = Val.second; // The array casted version of the pointer...
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for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
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Instruction *Inst = cast<Instruction>(*I);
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if (Inst->getOpcode() != Instruction::Add)
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continue; // We only care about add instructions
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BinaryOperator *Add = cast<BinaryOperator>(Inst);
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// Make sure the array is the first operand of the add expression...
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if (Add->getOperand(0) != V)
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Add->swapOperands();
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// Get the amount added to the pointer value...
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Value *AddAmount = Add->getOperand(1);
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}
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return false;
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}
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// Peephole Malloc instructions: we take a look at the use chain of the
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// malloc instruction, and try to find out if the following conditions hold:
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// 1. The malloc is of the form: 'malloc [sbyte], uint <constant>'
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// 2. The only users of the malloc are cast instructions
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// 3. Of the cast instructions, there is only one destination pointer type
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// [RTy] where the size of the pointed to object is equal to the number
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// of bytes allocated.
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//
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// If these conditions hold, we convert the malloc to allocate an [RTy]
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// element. This should be extended in the future to handle arrays. TODO
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//
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static bool PeepholeMallocInst(BasicBlock *BB, BasicBlock::iterator &BI) {
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MallocInst *MI = cast<MallocInst>(*BI);
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if (!MI->isArrayAllocation()) return false; // No array allocation?
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ConstPoolUInt *Amt = dyn_cast<ConstPoolUInt>(MI->getArraySize());
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if (Amt == 0 || MI->getAllocatedType() != ArrayType::get(Type::SByteTy))
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return false;
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// Get the number of bytes allocated...
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unsigned Size = Amt->getValue();
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const Type *ResultTy = 0;
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// Loop over all of the uses of the malloc instruction, inspecting casts.
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for (Value::use_iterator I = MI->use_begin(), E = MI->use_end();
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I != E; ++I) {
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if (!isa<CastInst>(*I)) {
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//cerr << "\tnon" << *I;
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return false; // A non cast user?
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}
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CastInst *CI = cast<CastInst>(*I);
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//cerr << "\t" << CI;
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// We only work on casts to pointer types for sure, be conservative
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if (!isa<PointerType>(CI->getType())) {
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cerr << "Found cast of malloc value to non pointer type:\n" << CI;
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return false;
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}
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const Type *DestTy = cast<PointerType>(CI->getType())->getValueType();
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if (TD.getTypeSize(DestTy) == Size && DestTy != ResultTy) {
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// Does the size of the allocated type match the number of bytes
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// allocated?
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//
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if (ResultTy == 0) {
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ResultTy = DestTy; // Keep note of this for future uses...
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} else {
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// It's overdefined! We don't know which type to convert to!
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return false;
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}
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}
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}
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// If we get this far, we have either found, or not, a type that is cast to
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// that is of the same size as the malloc instruction.
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if (!ResultTy) return false;
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PRINT_PEEPHOLE1("mall-refine:in ", MI);
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ReplaceInstWithInst(BB->getInstList(), BI,
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MI = new MallocInst(PointerType::get(ResultTy)));
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PRINT_PEEPHOLE1("mall-refine:out", MI);
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return true;
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}
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static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
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Instruction *I = *BI;
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// TODO: replace this with a DCE call
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if (I->use_size() == 0 && I->getType() != Type::VoidTy) return false;
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if (CastInst *CI = dyn_cast<CastInst>(I)) {
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Value *Src = CI->getOperand(0);
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Instruction *SrcI = dyn_cast<Instruction>(Src); // Nonnull if instr source
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const Type *DestTy = CI->getType();
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// Check for a cast of the same type as the destination!
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if (DestTy == Src->getType()) {
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PRINT_PEEPHOLE1("cast-of-self-ty", CI);
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CI->replaceAllUsesWith(Src);
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if (!Src->hasName() && CI->hasName()) {
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string Name = CI->getName();
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CI->setName(""); Src->setName(Name,
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BB->getParent()->getSymbolTable());
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}
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return true;
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}
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// Check for a cast of cast, where no size information is lost...
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if (SrcI)
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if (CastInst *CSrc = dyn_cast<CastInst>(SrcI))
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if (isReinterpretingCast(CI) + isReinterpretingCast(CSrc) < 2) {
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// We can only do c-c elimination if, at most, one cast does a
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// reinterpretation of the input data.
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//
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// If legal, make this cast refer the the original casts argument!
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//
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PRINT_PEEPHOLE2("cast-cast:in ", CI, CSrc);
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CI->setOperand(0, CSrc->getOperand(0));
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PRINT_PEEPHOLE1("cast-cast:out", CI);
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return true;
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}
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// Check to see if it's a cast of an instruction that does not depend on the
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// specific type of the operands to do it's job.
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if (!isReinterpretingCast(CI) &&
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ExpressionConvertableToType(Src, DestTy)) {
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PRINT_PEEPHOLE2("EXPR-CONV:in ", CI, Src);
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CI->setOperand(0, ConvertExpressionToType(Src, DestTy));
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BI = BB->begin(); // Rescan basic block. BI might be invalidated.
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PRINT_PEEPHOLE2("EXPR-CONV:out", CI, CI->getOperand(0));
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return true;
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}
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} else if (MallocInst *MI = dyn_cast<MallocInst>(I)) {
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if (PeepholeMallocInst(BB, BI)) return true;
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} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
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Value *Val = SI->getOperand(0);
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Value *Pointer = SI->getPtrOperand();
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// Peephole optimize the following instructions:
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// %t1 = getelementptr {<...>} * %StructPtr, <element indices>
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// store <elementty> %v, <elementty> * %t1
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//
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// Into: store <elementty> %v, {<...>} * %StructPtr, <element indices>
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//
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if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Pointer)) {
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PRINT_PEEPHOLE2("gep-store:in", GEP, SI);
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ReplaceInstWithInst(BB->getInstList(), BI,
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SI = new StoreInst(Val, GEP->getPtrOperand(),
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GEP->getIndexVec()));
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PRINT_PEEPHOLE1("gep-store:out", SI);
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return true;
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}
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// Peephole optimize the following instructions:
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// %t = cast <T1>* %P to <T2> * ;; If T1 is losslessly convertable to T2
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// store <T2> %V, <T2>* %t
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//
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// Into:
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// %t = cast <T2> %V to <T1>
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// store <T1> %t2, <T1>* %P
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//
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if (CastInst *CI = dyn_cast<CastInst>(Pointer))
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if (Value *CastSrc = CI->getOperand(0)) // CSPT = CastSrcPointerType
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if (PointerType *CSPT = dyn_cast<PointerType>(CastSrc->getType()))
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if (losslessCastableTypes(Val->getType(), // convertable types!
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CSPT->getValueType()) &&
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!SI->hasIndices()) { // No subscripts yet!
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PRINT_PEEPHOLE3("st-src-cast:in ", Pointer, Val, SI);
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// Insert the new T cast instruction... stealing old T's name
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CastInst *NCI = new CastInst(Val, CSPT->getValueType(),
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CI->getName());
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CI->setName("");
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BI = BB->getInstList().insert(BI, NCI)+1;
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// Replace the old store with a new one!
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ReplaceInstWithInst(BB->getInstList(), BI,
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SI = new StoreInst(NCI, CastSrc));
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PRINT_PEEPHOLE3("st-src-cast:out", NCI, CastSrc, SI);
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return true;
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}
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} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
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Value *Pointer = LI->getPtrOperand();
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// Peephole optimize the following instructions:
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// %t1 = getelementptr {<...>} * %StructPtr, <element indices>
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// %V = load <elementty> * %t1
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//
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// Into: load {<...>} * %StructPtr, <element indices>
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//
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if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Pointer)) {
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PRINT_PEEPHOLE2("gep-load:in", GEP, LI);
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ReplaceInstWithInst(BB->getInstList(), BI,
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LI = new LoadInst(GEP->getPtrOperand(),
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GEP->getIndexVec()));
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PRINT_PEEPHOLE1("gep-load:out", LI);
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return true;
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}
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} else if (I->getOpcode() == Instruction::Add &&
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isa<CastInst>(I->getOperand(1))) {
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// Peephole optimize the following instructions:
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// %t1 = cast ulong <const int> to {<...>} *
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// %t2 = add {<...>} * %SP, %t1 ;; Constant must be 2nd operand
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//
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// or
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// %t1 = cast {<...>}* %SP to int*
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// %t5 = cast ulong <const int> to int*
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// %t2 = add int* %t1, %t5 ;; int is same size as field
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//
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// Into: %t3 = getelementptr {<...>} * %SP, <element indices>
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// %t2 = cast <eltype> * %t3 to {<...>}*
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//
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Value *AddOp1 = I->getOperand(0);
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CastInst *AddOp2 = cast<CastInst>(I->getOperand(1));
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ConstPoolUInt *OffsetV = dyn_cast<ConstPoolUInt>(AddOp2->getOperand(0));
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unsigned Offset = OffsetV ? OffsetV->getValue() : 0;
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Value *SrcPtr; // Of type pointer to struct...
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const StructType *StructTy;
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if ((StructTy = getPointedToStruct(AddOp1->getType()))) {
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SrcPtr = AddOp1; // Handle the first case...
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} else if (CastInst *AddOp1c = dyn_cast<CastInst>(AddOp1)) {
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SrcPtr = AddOp1c->getOperand(0); // Handle the second case...
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StructTy = getPointedToStruct(SrcPtr->getType());
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}
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// Only proceed if we have detected all of our conditions successfully...
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if (Offset && StructTy && SrcPtr && Offset < TD.getTypeSize(StructTy)) {
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const StructLayout *SL = TD.getStructLayout(StructTy);
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vector<ConstPoolVal*> Offsets;
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unsigned ActualOffset = Offset;
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const Type *ElTy = getStructOffsetType(StructTy, ActualOffset, Offsets);
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|
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if (getPointedToStruct(AddOp1->getType())) { // case 1
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PRINT_PEEPHOLE2("add-to-gep1:in", AddOp2, I);
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} else {
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PRINT_PEEPHOLE3("add-to-gep2:in", AddOp1, AddOp2, I);
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}
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GetElementPtrInst *GEP = new GetElementPtrInst(SrcPtr, Offsets);
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BI = BB->getInstList().insert(BI, GEP)+1;
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|
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assert(Offset-ActualOffset == 0 &&
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"GEP to middle of element not implemented yet!");
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|
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ReplaceInstWithInst(BB->getInstList(), BI,
|
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I = new CastInst(GEP, I->getType()));
|
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PRINT_PEEPHOLE2("add-to-gep:out", GEP, I);
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return true;
|
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}
|
|
}
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|
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return false;
|
|
}
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static bool DoRaisePass(Method *M) {
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bool Changed = false;
|
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for (Method::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI) {
|
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BasicBlock *BB = *MI;
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BasicBlock::InstListType &BIL = BB->getInstList();
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for (BasicBlock::iterator BI = BB->begin(); BI != BB->end();) {
|
|
if (PeepholeOptimize(BB, BI))
|
|
Changed = true;
|
|
else
|
|
++BI;
|
|
}
|
|
}
|
|
return Changed;
|
|
}
|
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|
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// RaisePointerReferences::doit - Raise a method representation to a higher
|
|
// level.
|
|
//
|
|
bool RaisePointerReferences::doit(Method *M) {
|
|
if (M->isExternal()) return false;
|
|
bool Changed = false;
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|
|
while (DoRaisePass(M)) Changed = true;
|
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|
|
// PtrCasts - Keep a mapping between the pointer values (the key of the
|
|
// map), and the cast to array pointer (the value) in this map. This is
|
|
// used when converting pointer math into array addressing.
|
|
//
|
|
map<Value*, CastInst*> PtrCasts;
|
|
|
|
// Insert casts for all incoming pointer values. Keep track of those casts
|
|
// and the identified incoming values in the PtrCasts map.
|
|
//
|
|
Changed |= DoInsertArrayCasts(M, PtrCasts);
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|
|
// Loop over each incoming pointer variable, replacing indexing arithmetic
|
|
// with getelementptr calls.
|
|
//
|
|
Changed |= reduce_apply_bool(PtrCasts.begin(), PtrCasts.end(),
|
|
ptr_fun(DoEliminatePointerArithmetic));
|
|
|
|
return Changed;
|
|
}
|