xref: /llvm-project/llvm/lib/Target/XCore/XCoreFrameToArgsOffsetElim.cpp (revision ed8019d9fbed2e6a6b08f8f73e9fa54a24f3ed52)
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/Target/TargetMachine.h"
19 using namespace llvm;
20 
21 namespace {
22   struct XCoreFTAOElim : public MachineFunctionPass {
23     static char ID;
24     XCoreFTAOElim() : MachineFunctionPass(ID) {}
25 
26     bool runOnMachineFunction(MachineFunction &Fn) override;
27     MachineFunctionProperties getRequiredProperties() const override {
28       return MachineFunctionProperties().set(
29           MachineFunctionProperties::Property::NoVRegs);
30     }
31 
32     StringRef getPassName() const override {
33       return "XCore FRAME_TO_ARGS_OFFSET Elimination";
34     }
35   };
36   char XCoreFTAOElim::ID = 0;
37 }
38 
39 /// createXCoreFrameToArgsOffsetEliminationPass - returns an instance of the
40 /// Frame to args offset elimination pass
41 FunctionPass *llvm::createXCoreFrameToArgsOffsetEliminationPass() {
42   return new XCoreFTAOElim();
43 }
44 
45 bool XCoreFTAOElim::runOnMachineFunction(MachineFunction &MF) {
46   const XCoreInstrInfo &TII =
47       *static_cast<const XCoreInstrInfo *>(MF.getSubtarget().getInstrInfo());
48   unsigned StackSize = MF.getFrameInfo().getStackSize();
49   for (MachineBasicBlock &MBB : MF) {
50     for (MachineBasicBlock::iterator MBBI = MBB.begin(), EE = MBB.end();
51          MBBI != EE; ++MBBI) {
52       if (MBBI->getOpcode() == XCore::FRAME_TO_ARGS_OFFSET) {
53         MachineInstr &OldInst = *MBBI;
54         Register Reg = OldInst.getOperand(0).getReg();
55         MBBI = TII.loadImmediate(MBB, MBBI, Reg, StackSize);
56         OldInst.eraseFromParent();
57       }
58     }
59   }
60   return true;
61 }
62