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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35731 91177308-0d34-0410-b5e6-96231b3b80d8
113 lines
4.8 KiB
C++
113 lines
4.8 KiB
C++
//===-- Transform/Utils/BasicBlockUtils.h - BasicBlock Utils ----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This family of functions perform manipulations on basic blocks, and
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// instructions contained within basic blocks.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_UTILS_BASICBLOCK_H
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#define LLVM_TRANSFORMS_UTILS_BASICBLOCK_H
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// FIXME: Move to this file: BasicBlock::removePredecessor, BB::splitBasicBlock
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#include "llvm/BasicBlock.h"
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#include "llvm/Support/CFG.h"
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namespace llvm {
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class Instruction;
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class Pass;
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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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void ReplaceInstWithValue(BasicBlock::InstListType &BIL,
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BasicBlock::iterator &BI, Value *V);
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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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void ReplaceInstWithInst(BasicBlock::InstListType &BIL,
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BasicBlock::iterator &BI, Instruction *I);
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// ReplaceInstWithInst - Replace the instruction specified by From with the
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// instruction specified by To.
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//
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void ReplaceInstWithInst(Instruction *From, Instruction *To);
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// RemoveSuccessor - Change the specified terminator instruction such that its
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// successor #SuccNum no longer exists. Because this reduces the outgoing
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// degree of the current basic block, the actual terminator instruction itself
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// may have to be changed. In the case where the last successor of the block is
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// deleted, a return instruction is inserted in its place which can cause a
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// suprising change in program behavior if it is not expected.
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//
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void RemoveSuccessor(TerminatorInst *TI, unsigned SuccNum);
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/// isCriticalEdge - Return true if the specified edge is a critical edge.
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/// Critical edges are edges from a block with multiple successors to a block
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/// with multiple predecessors.
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///
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bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
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bool AllowIdenticalEdges = false);
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/// SplitCriticalEdge - If this edge is a critical edge, insert a new node to
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/// split the critical edge. This will update ETForest, ImmediateDominator,
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/// DominatorTree, and DominatorFrontier information if it is available, thus
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/// calling this pass will not invalidate either of them. This returns true if
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/// the edge was split, false otherwise. If MergeIdenticalEdges is true (the
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/// default), *all* edges from TI to the specified successor will be merged into
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/// the same critical edge block. This is most commonly interesting with switch
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/// instructions, which may have many edges to any one destination. This
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/// ensures that all edges to that dest go to one block instead of each going to
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/// a different block, but isn't the standard definition of a "critical edge".
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///
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bool SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P = 0,
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bool MergeIdenticalEdges = false);
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inline bool SplitCriticalEdge(BasicBlock *BB, succ_iterator SI, Pass *P = 0) {
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return SplitCriticalEdge(BB->getTerminator(), SI.getSuccessorIndex(), P);
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}
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/// SplitCriticalEdge - If the edge from *PI to BB is not critical, return
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/// false. Otherwise, split all edges between the two blocks and return true.
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/// This updates all of the same analyses as the other SplitCriticalEdge
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/// function. If P is specified, it updates the analyses
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/// described above.
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inline bool SplitCriticalEdge(BasicBlock *Succ, pred_iterator PI, Pass *P = 0) {
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bool MadeChange = false;
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TerminatorInst *TI = (*PI)->getTerminator();
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for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
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if (TI->getSuccessor(i) == Succ)
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MadeChange |= SplitCriticalEdge(TI, i, P);
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return MadeChange;
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}
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/// SplitCriticalEdge - If an edge from Src to Dst is critical, split the edge
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/// and return true, otherwise return false. This method requires that there be
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/// an edge between the two blocks. If P is specified, it updates the analyses
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/// described above.
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inline bool SplitCriticalEdge(BasicBlock *Src, BasicBlock *Dst, Pass *P = 0,
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bool MergeIdenticalEdges = false) {
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TerminatorInst *TI = Src->getTerminator();
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unsigned i = 0;
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while (1) {
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assert(i != TI->getNumSuccessors() && "Edge doesn't exist!");
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if (TI->getSuccessor(i) == Dst)
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return SplitCriticalEdge(TI, i, P, MergeIdenticalEdges);
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++i;
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}
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}
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} // End llvm namespace
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#endif
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