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//===-- CodeGen/MachineJumpTableInfo.h - Abstract Jump Tables --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Nate Begeman and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The MachineJumpTableInfo class keeps track of jump tables referenced by
// lowered switch instructions in the MachineFunction.
//
// Instructions reference the address of these jump tables through the use of
// MO_JumpTableIndex values. When emitting assembly or machine code, these
// virtual address references are converted to refer to the address of the
// function jump tables.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H
#define LLVM_CODEGEN_MACHINEJUMPTABLEINFO_H
#include <vector>
#include <iosfwd>
namespace llvm {
class MachineBasicBlock;
class TargetData;
/// MachineJumpTableEntry - One jump table in the jump table info.
///
struct MachineJumpTableEntry {
/// MBBs - The vector of basic blocks from which to create the jump table.
std::vector<MachineBasicBlock*> MBBs;
explicit MachineJumpTableEntry(const std::vector<MachineBasicBlock*> &M)
: MBBs(M) {}
};
class MachineJumpTableInfo {
unsigned EntrySize;
unsigned Alignment;
std::vector<MachineJumpTableEntry> JumpTables;
public:
MachineJumpTableInfo(unsigned Size, unsigned Align)
: EntrySize(Size), Alignment(Align) {}
/// getJumpTableIndex - Create a new jump table or return an existing one.
///
unsigned getJumpTableIndex(const std::vector<MachineBasicBlock*> &DestBBs);
/// isEmpty - Return true if there are no jump tables.
///
bool isEmpty() const { return JumpTables.empty(); }
const std::vector<MachineJumpTableEntry> &getJumpTables() const {
return JumpTables;
}
/// RemoveJumpTable - Mark the specific index as being dead. This will cause
/// it to not be emitted.
void RemoveJumpTable(unsigned Idx) {
JumpTables[Idx].MBBs.clear();
}
/// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
/// the jump tables to branch to New instead.
bool ReplaceMBBInJumpTables(MachineBasicBlock *Old, MachineBasicBlock *New) {
assert(Old != New && "Not making a change?");
bool MadeChange = false;
for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
MachineJumpTableEntry &JTE = JumpTables[i];
for (unsigned j = 0, e = JTE.MBBs.size(); j != e; ++j)
if (JTE.MBBs[j] == Old) {
JTE.MBBs[j] = New;
MadeChange = true;
}
}
return MadeChange;
}
/// getEntrySize - Returns the size of an individual field in a jump table.
///
unsigned getEntrySize() const { return EntrySize; }
/// getAlignment - returns the target's preferred alignment for jump tables
unsigned getAlignment() const { return Alignment; }
/// print - Used by the MachineFunction printer to print information about
/// jump tables. Implemented in MachineFunction.cpp
///
void print(std::ostream &OS) const;
void print(std::ostream *OS) const { if (OS) print(*OS); }
/// dump - Call print(std::cerr) to be called from the debugger.
///
void dump() const;
};
} // End llvm namespace
#endif
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