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slightly simplify and document SSARegMap.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45465 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-12-30 23:40:31 +00:00
parent 8aa797aa51
commit 1c0780985d
1 changed files with 24 additions and 19 deletions
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43
include/llvm/CodeGen/SSARegMap.h
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@ -7,10 +7,7 @@
//
//===----------------------------------------------------------------------===//
//
// Map register numbers to register classes that are correctly sized (typed) to
// hold the information. Assists register allocation. Contained by
// MachineFunction, should be deleted by register allocator when it is no
// longer needed.
// This file defines the SSARegMap class.
//
//===----------------------------------------------------------------------===//
@ -18,21 +15,28 @@
#define LLVM_CODEGEN_SSAREGMAP_H
#include "llvm/Target/MRegisterInfo.h"
#include "llvm/ADT/IndexedMap.h"
#include <vector>
namespace llvm {
class TargetRegisterClass;
/// SSARegMap - Keep track of information for each virtual register, including
/// its register class.
class SSARegMap {
IndexedMap<const TargetRegisterClass*, VirtReg2IndexFunctor> RegClassMap;
unsigned NextRegNum;
/// VRegInfo - Information we keep for each virtual register. The entries in
/// this vector are actually converted to vreg numbers by adding the
/// MRegisterInfo::FirstVirtualRegister delta to their index.
std::vector<const TargetRegisterClass*> VRegInfo;
public:
SSARegMap() {
VRegInfo.reserve(256);
}
public:
SSARegMap() : NextRegNum(MRegisterInfo::FirstVirtualRegister) { }
const TargetRegisterClass* getRegClass(unsigned Reg) {
return RegClassMap[Reg];
/// getRegClass - Return the register class of the specified virtual register.
const TargetRegisterClass *getRegClass(unsigned Reg) {
Reg -= MRegisterInfo::FirstVirtualRegister;
assert(Reg < VRegInfo.size() && "Invalid vreg!");
return VRegInfo[Reg];
}
/// createVirtualRegister - Create and return a new virtual register in the
@ -40,13 +44,14 @@ class SSARegMap {
///
unsigned createVirtualRegister(const TargetRegisterClass *RegClass) {
assert(RegClass && "Cannot create register without RegClass!");
RegClassMap.grow(NextRegNum);
RegClassMap[NextRegNum] = RegClass;
return NextRegNum++;
VRegInfo.push_back(RegClass);
return getLastVirtReg();
}
/// getLastVirtReg - Return the highest currently assigned virtual register.
///
unsigned getLastVirtReg() const {
return NextRegNum - 1;
return VRegInfo.size()+MRegisterInfo::FirstVirtualRegister-1;
}
};