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d1ec31dca5
always create a new jump table. The intention was to avoid merging jump tables in SelectionDAGBuilder, and to wait for the branch folding pass to merge tables. Unfortunately, the same getJumpTableIndex() method is also used to merge tables in branch folding, so as a result of this change branch tables are never merged. Worse, the branch folding code is expecting getJumpTableIndex to always return the index of an existing table, but with this change, it never does so. In at least some cases, e.g., pr6543, this creates references to non-existent tables. I've fixed the problem by adding a new createJumpTableIndex function, which will always create a new table, and I've changed getJumpTableIndex to only look at existing tables. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98845 91177308-0d34-0410-b5e6-96231b3b80d8
130 lines
4.3 KiB
C++
130 lines
4.3 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 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 <vector>
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#include <cassert>
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namespace llvm {
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class MachineBasicBlock;
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class TargetData;
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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_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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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 TargetData &TD) const;
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/// getEntryAlignment - Return the alignment of each entry in the jump table.
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unsigned getEntryAlignment(const TargetData &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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/// getJumpTableIndex - Return the index for an existing jump table.
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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
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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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