1 //===-- llvm/CodeGen/AllocationOrder.cpp - Allocation Order ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements an allocation order for virtual registers.
11 //
12 // The preferred allocation order for a virtual register depends on allocation
13 // hints and target hooks. The AllocationOrder class encapsulates all of that.
14 //
15 //===----------------------------------------------------------------------===//
16
17 #include "AllocationOrder.h"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/CodeGen/MachineRegisterInfo.h"
20 #include "llvm/CodeGen/RegisterClassInfo.h"
21 #include "llvm/CodeGen/VirtRegMap.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/raw_ostream.h"
24
25 using namespace llvm;
26
27 #define DEBUG_TYPE "regalloc"
28
29 // Compare VirtRegMap::getRegAllocPref().
AllocationOrder(unsigned VirtReg,const VirtRegMap & VRM,const RegisterClassInfo & RegClassInfo,const LiveRegMatrix * Matrix)30 AllocationOrder::AllocationOrder(unsigned VirtReg,
31 const VirtRegMap &VRM,
32 const RegisterClassInfo &RegClassInfo,
33 const LiveRegMatrix *Matrix)
34 : Pos(0) {
35 const MachineFunction &MF = VRM.getMachineFunction();
36 const TargetRegisterInfo *TRI = &VRM.getTargetRegInfo();
37 Order = RegClassInfo.getOrder(MF.getRegInfo().getRegClass(VirtReg));
38 TRI->getRegAllocationHints(VirtReg, Order, Hints, MF, &VRM, Matrix);
39 rewind();
40
41 DEBUG({
42 if (!Hints.empty()) {
43 dbgs() << "hints:";
44 for (unsigned I = 0, E = Hints.size(); I != E; ++I)
45 dbgs() << ' ' << PrintReg(Hints[I], TRI);
46 dbgs() << '\n';
47 }
48 });
49 #ifndef NDEBUG
50 for (unsigned I = 0, E = Hints.size(); I != E; ++I)
51 assert(std::find(Order.begin(), Order.end(), Hints[I]) != Order.end() &&
52 "Target hint is outside allocation order.");
53 #endif
54 }
55