1 //===-- XCoreFrameToArgsOffsetElim.cpp ----------------------------*- C++ -*-=//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Replace Pseudo FRAME_TO_ARGS_OFFSET with the appropriate real offset.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "XCore.h"
14 #include "XCoreInstrInfo.h"
15 #include "XCoreSubtarget.h"
16 #include "llvm/CodeGen/MachineFrameInfo.h"
17 #include "llvm/CodeGen/MachineFunctionPass.h"
18 #include "llvm/CodeGen/MachineInstrBuilder.h"
19 #include "llvm/Support/raw_ostream.h"
20 #include "llvm/Target/TargetMachine.h"
21 using namespace llvm;
22 
23 namespace {
24   struct XCoreFTAOElim : public MachineFunctionPass {
25     static char ID;
26     XCoreFTAOElim() : MachineFunctionPass(ID) {}
27 
28     bool runOnMachineFunction(MachineFunction &Fn) override;
29     MachineFunctionProperties getRequiredProperties() const override {
30       return MachineFunctionProperties().set(
31           MachineFunctionProperties::Property::NoVRegs);
32     }
33 
34     StringRef getPassName() const override {
35       return "XCore FRAME_TO_ARGS_OFFSET Elimination";
36     }
37   };
38   char XCoreFTAOElim::ID = 0;
39 }
40 
41 /// createXCoreFrameToArgsOffsetEliminationPass - returns an instance of the
42 /// Frame to args offset elimination pass
43 FunctionPass *llvm::createXCoreFrameToArgsOffsetEliminationPass() {
44   return new XCoreFTAOElim();
45 }
46 
47 bool XCoreFTAOElim::runOnMachineFunction(MachineFunction &MF) {
48   const XCoreInstrInfo &TII =
49       *static_cast<const XCoreInstrInfo *>(MF.getSubtarget().getInstrInfo());
50   unsigned StackSize = MF.getFrameInfo().getStackSize();
51   for (MachineBasicBlock &MBB : MF) {
52     for (MachineBasicBlock::iterator MBBI = MBB.begin(), EE = MBB.end();
53          MBBI != EE; ++MBBI) {
54       if (MBBI->getOpcode() == XCore::FRAME_TO_ARGS_OFFSET) {
55         MachineInstr &OldInst = *MBBI;
56         Register Reg = OldInst.getOperand(0).getReg();
57         MBBI = TII.loadImmediate(MBB, MBBI, Reg, StackSize);
58         OldInst.eraseFromParent();
59       }
60     }
61   }
62   return true;
63 }
64