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130 lines
4.4 KiB
130 lines
4.4 KiB
//===-- 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 is distributed under the University of Illinois Open Source
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// 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 <cassert>
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#include <vector>
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namespace llvm {
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class MachineBasicBlock;
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class DataLayout;
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class raw_ostream;
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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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explicit MachineJumpTableEntry(const std::vector<MachineBasicBlock*> &M)
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: MBBs(M) {}
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};
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class MachineJumpTableInfo {
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public:
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/// JTEntryKind - This enum indicates how each entry of the jump table is
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/// represented and emitted.
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enum JTEntryKind {
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/// EK_BlockAddress - Each entry is a plain address of block, e.g.:
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/// .word LBB123
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EK_BlockAddress,
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/// EK_GPRel64BlockAddress - Each entry is an address of block, encoded
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/// with a relocation as gp-relative, e.g.:
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/// .gpdword LBB123
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EK_GPRel64BlockAddress,
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/// EK_GPRel32BlockAddress - Each entry is an address of block, encoded
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/// with a relocation as gp-relative, e.g.:
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/// .gprel32 LBB123
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EK_GPRel32BlockAddress,
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/// EK_LabelDifference32 - Each entry is the address of the block minus
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/// the address of the jump table. This is used for PIC jump tables where
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/// gprel32 is not supported. e.g.:
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/// .word LBB123 - LJTI1_2
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/// If the .set directive is supported, this is emitted as:
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/// .set L4_5_set_123, LBB123 - LJTI1_2
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/// .word L4_5_set_123
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EK_LabelDifference32,
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/// EK_Inline - Jump table entries are emitted inline at their point of
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/// use. It is the responsibility of the target to emit the entries.
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EK_Inline,
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/// EK_Custom32 - Each entry is a 32-bit value that is custom lowered by the
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/// TargetLowering::LowerCustomJumpTableEntry hook.
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EK_Custom32
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};
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private:
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JTEntryKind EntryKind;
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std::vector<MachineJumpTableEntry> JumpTables;
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public:
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explicit MachineJumpTableInfo(JTEntryKind Kind): EntryKind(Kind) {}
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JTEntryKind getEntryKind() const { return EntryKind; }
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/// getEntrySize - Return the size of each entry in the jump table.
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unsigned getEntrySize(const DataLayout &TD) const;
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/// getEntryAlignment - Return the alignment of each entry in the jump table.
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unsigned getEntryAlignment(const DataLayout &TD) const;
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/// createJumpTableIndex - Create a new jump table.
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///
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unsigned createJumpTableIndex(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
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/// prevent it from being 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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/// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
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/// the jump table to branch to New instead.
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bool ReplaceMBBInJumpTable(unsigned Idx, MachineBasicBlock *Old,
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MachineBasicBlock *New);
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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(raw_ostream &OS) const;
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/// dump - Call to stderr.
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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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