llvm-6502/include/llvm/Analysis/JumpInstrTableInfo.h
Tom Roeder 5d0f7af3dc Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute.
It includes a pass that rewrites all indirect calls to jumptable functions to pass through these tables.

This also adds backend support for generating the jump-instruction tables on ARM and X86.
Note that since the jumptable attribute creates a second function pointer for a
function, any function marked with jumptable must also be marked with unnamed_addr.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210280 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-05 19:29:43 +00:00

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//===-- JumpInstrTableInfo.h: Info for Jump-Instruction Tables --*- C++ -*-===//
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief Information about jump-instruction tables that have been created by
/// JumpInstrTables pass.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_JUMPINSTRTABLEINFO_H
#define LLVM_ANALYSIS_JUMPINSTRTABLEINFO_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/Pass.h"
#include <vector>
namespace llvm {
class Function;
class FunctionType;
/// This class stores information about jump-instruction tables created by the
/// JumpInstrTables pass (in lib/CodeGen/JumpInstrTables.cpp). Each table is a
/// map from a function type to a vector of pairs. The first element of each
/// pair is the function that has the jumptable annotation. The second element
/// is a function that was declared by JumpInstrTables and used to replace all
/// address-taking sites for the original function.
///
/// The information in this pass is used in AsmPrinter
/// (lib/CodeGen/AsmPrinter/AsmPrinter.cpp) to generate the required assembly
/// for the jump-instruction tables.
class JumpInstrTableInfo : public ImmutablePass {
public:
static char ID;
JumpInstrTableInfo();
virtual ~JumpInstrTableInfo();
const char *getPassName() const override {
return "Jump-Instruction Table Info";
}
typedef std::pair<Function *, Function *> JumpPair;
typedef DenseMap<FunctionType *, std::vector<JumpPair> > JumpTables;
/// Inserts an entry in a table, adding the table if it doesn't exist.
void insertEntry(FunctionType *TableFunTy, Function *Target, Function *Jump);
/// Gets the tables.
const JumpTables &getTables() const { return Tables; }
private:
JumpTables Tables;
};
}
#endif /* LLVM_ANALYSIS_JUMPINSTRTABLEINFO_H */