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llvm-mirror/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
Derek Schuff 2f77371cea [WebAssembly] Fix uses of FrameIndex as store values
Previously the code assumed all uses of FI on loads and stores were as
addresses. This checks whether the use is the address or a value and
handles the latter case as it does for non-memory instructions.

llvm-svn: 259306
2016-01-30 21:43:08 +00:00

118 lines
4.4 KiB
C++

//===-- WebAssemblyRegisterInfo.cpp - WebAssembly Register Information ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief This file contains the WebAssembly implementation of the
/// TargetRegisterInfo class.
///
//===----------------------------------------------------------------------===//
#include "WebAssemblyRegisterInfo.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "WebAssemblyFrameLowering.h"
#include "WebAssemblyInstrInfo.h"
#include "WebAssemblyMachineFunctionInfo.h"
#include "WebAssemblySubtarget.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
#define DEBUG_TYPE "wasm-reg-info"
#define GET_REGINFO_TARGET_DESC
#include "WebAssemblyGenRegisterInfo.inc"
WebAssemblyRegisterInfo::WebAssemblyRegisterInfo(const Triple &TT)
: WebAssemblyGenRegisterInfo(0), TT(TT) {}
const MCPhysReg *
WebAssemblyRegisterInfo::getCalleeSavedRegs(const MachineFunction *) const {
static const MCPhysReg CalleeSavedRegs[] = {0};
return CalleeSavedRegs;
}
BitVector
WebAssemblyRegisterInfo::getReservedRegs(const MachineFunction & /*MF*/) const {
BitVector Reserved(getNumRegs());
for (auto Reg : {WebAssembly::SP32, WebAssembly::SP64, WebAssembly::FP32,
WebAssembly::FP64})
Reserved.set(Reg);
return Reserved;
}
void WebAssemblyRegisterInfo::eliminateFrameIndex(
MachineBasicBlock::iterator II, int SPAdj, unsigned FIOperandNum,
RegScavenger * /*RS*/) const {
assert(SPAdj == 0);
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
const MachineFrameInfo &MFI = *MF.getFrameInfo();
int64_t FrameOffset = MFI.getStackSize() + MFI.getObjectOffset(FrameIndex);
if (MI.mayLoadOrStore() && FIOperandNum == WebAssembly::MemOpAddressOperandNo) {
// If this is the address operand of a load or store, make it relative to SP
// and fold the frame offset directly in.
assert(FrameOffset >= 0 && MI.getOperand(1).getImm() >= 0);
int64_t Offset = MI.getOperand(1).getImm() + FrameOffset;
if (static_cast<uint64_t>(Offset) > std::numeric_limits<uint32_t>::max()) {
// If this happens the program is invalid, but better to error here than
// generate broken code.
report_fatal_error("Memory offset field overflow");
}
MI.getOperand(FIOperandNum - 1).setImm(Offset);
MI.getOperand(FIOperandNum)
.ChangeToRegister(WebAssembly::SP32, /*IsDef=*/false);
} else {
// Otherwise create an i32.add SP, offset and make it the operand.
auto &MRI = MF.getRegInfo();
const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
unsigned FIRegOperand = WebAssembly::SP32;
if (FrameOffset) {
FIRegOperand = MRI.createVirtualRegister(&WebAssembly::I32RegClass);
BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(WebAssembly::CONST_I32),
FIRegOperand)
.addImm(FrameOffset);
BuildMI(MBB, MI, MI.getDebugLoc(), TII->get(WebAssembly::ADD_I32),
FIRegOperand)
.addReg(WebAssembly::SP32)
.addReg(FIRegOperand);
}
MI.getOperand(FIOperandNum).ChangeToRegister(FIRegOperand, /*IsDef=*/false);
}
}
unsigned
WebAssemblyRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
static const unsigned Regs[2][2] = {
/* !isArch64Bit isArch64Bit */
/* !hasFP */ {WebAssembly::SP32, WebAssembly::SP64},
/* hasFP */ {WebAssembly::FP32, WebAssembly::FP64}};
const WebAssemblyFrameLowering *TFI = getFrameLowering(MF);
return Regs[TFI->hasFP(MF)][TT.isArch64Bit()];
}
const TargetRegisterClass *
WebAssemblyRegisterInfo::getPointerRegClass(const MachineFunction &MF,
unsigned Kind) const {
assert(Kind == 0 && "Only one kind of pointer on WebAssembly");
if (MF.getSubtarget<WebAssemblySubtarget>().hasAddr64())
return &WebAssembly::I64RegClass;
return &WebAssembly::I32RegClass;
}