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2. Allow the jit to handle PIC relocable jump tables. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32581 91177308-0d34-0410-b5e6-96231b3b80d8
102 lines
3.2 KiB
C++
102 lines
3.2 KiB
C++
//===-- CodeGen/MachineJumpTableInfo.h - Abstract Jump Tables --*- 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 Nate Begeman and is distributed under the
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// 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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// The MachineJumpTableInfo class keeps track of jump tables referenced by
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// lowered switch instructions in the MachineFunction.
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//
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// Instructions reference the address of these jump tables through the use of
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// MO_JumpTableIndex values. When emitting assembly or machine code, these
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// virtual address references are converted to refer to the address of the
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// function jump tables.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H
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#define LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H
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#include <vector>
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#include <iosfwd>
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namespace llvm {
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class MachineBasicBlock;
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class TargetData;
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/// MachineJumpTableEntry - One jump table in the jump table info.
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///
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struct MachineJumpTableEntry {
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/// MBBs - The vector of basic blocks from which to create the jump table.
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std::vector<MachineBasicBlock*> MBBs;
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MachineJumpTableEntry(const std::vector<MachineBasicBlock*> &M) : MBBs(M) {}
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};
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class MachineJumpTableInfo {
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const TargetData *TD;
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unsigned EntrySize;
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std::vector<MachineJumpTableEntry> JumpTables;
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public:
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MachineJumpTableInfo(const TargetData *td, unsigned ES)
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: TD(td), EntrySize(ES) {}
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/// getJumpTableIndex - Create a new jump table or return an existing one.
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///
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unsigned getJumpTableIndex(const std::vector<MachineBasicBlock*> &DestBBs);
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/// isEmpty - Return true if there are no jump tables.
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///
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bool isEmpty() const { return JumpTables.empty(); }
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const std::vector<MachineJumpTableEntry> &getJumpTables() const {
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return JumpTables;
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}
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/// RemoveJumpTable - Mark the specific index as being dead. This will cause
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/// it to not be emitted.
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void RemoveJumpTable(unsigned Idx) {
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JumpTables[Idx].MBBs.clear();
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}
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/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
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/// the jump tables to branch to New instead.
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bool ReplaceMBBInJumpTables(MachineBasicBlock *Old, MachineBasicBlock *New) {
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assert(Old != New && "Not making a change?");
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bool MadeChange = false;
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for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
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MachineJumpTableEntry &JTE = JumpTables[i];
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for (unsigned j = 0, e = JTE.MBBs.size(); j != e; ++j)
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if (JTE.MBBs[j] == Old) {
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JTE.MBBs[j] = New;
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MadeChange = true;
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}
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}
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return MadeChange;
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}
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/// getEntrySize - Returns the size of an individual field in a jump table.
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///
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unsigned getEntrySize() const { return EntrySize; }
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/// getAlignment - returns the target's preferred alignment for jump tables
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unsigned getAlignment() const;
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/// print - Used by the MachineFunction printer to print information about
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/// jump tables. Implemented in MachineFunction.cpp
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///
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void print(std::ostream &OS) const;
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/// dump - Call print(std::cerr) to be called from the debugger.
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///
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void dump() const;
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};
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} // End llvm namespace
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#endif
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