WebAssemblyFrameLowering.cpp revision 288943 
1//===-- WebAssemblyFrameLowering.cpp - WebAssembly Frame Lowering ----------==//
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/// \file
11/// \brief This file contains the WebAssembly implementation of
12/// TargetFrameLowering class.
13///
14/// On WebAssembly, there aren't a lot of things to do here. There are no
15/// callee-saved registers to save, and no spill slots.
16///
17/// The stack grows downward.
18///
19//===----------------------------------------------------------------------===//
20
21#include "WebAssemblyFrameLowering.h"
22#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
23#include "WebAssemblyInstrInfo.h"
24#include "WebAssemblyMachineFunctionInfo.h"
25#include "WebAssemblySubtarget.h"
26#include "WebAssemblyTargetMachine.h"
27#include "llvm/CodeGen/MachineFrameInfo.h"
28#include "llvm/CodeGen/MachineFunction.h"
29#include "llvm/CodeGen/MachineInstrBuilder.h"
30#include "llvm/CodeGen/MachineModuleInfo.h"
31#include "llvm/CodeGen/MachineRegisterInfo.h"
32#include "llvm/Support/Debug.h"
33using namespace llvm;
34
35#define DEBUG_TYPE "wasm-frame-info"
36
37// TODO: Implement a red zone?
38
39/// Return true if the specified function should have a dedicated frame pointer
40/// register.
41bool WebAssemblyFrameLowering::hasFP(const MachineFunction &MF) const {
42  llvm_unreachable("TODO: implement hasFP");
43}
44
45/// Under normal circumstances, when a frame pointer is not required, we reserve
46/// argument space for call sites in the function immediately on entry to the
47/// current function. This eliminates the need for add/sub sp brackets around
48/// call sites. Returns true if the call frame is included as part of the stack
49/// frame.
50bool WebAssemblyFrameLowering::hasReservedCallFrame(
51    const MachineFunction &MF) const {
52  return !MF.getFrameInfo()->hasVarSizedObjects();
53}
54
55void WebAssemblyFrameLowering::eliminateCallFramePseudoInstr(
56    MachineFunction &MF, MachineBasicBlock &MBB,
57    MachineBasicBlock::iterator I) const {
58  llvm_unreachable("TODO: implement eliminateCallFramePseudoInstr");
59}
60
61void WebAssemblyFrameLowering::emitPrologue(MachineFunction &MF,
62                                            MachineBasicBlock &MBB) const {
63  llvm_unreachable("TODO: implement emitPrologue");
64}
65
66void WebAssemblyFrameLowering::emitEpilogue(MachineFunction &MF,
67                                            MachineBasicBlock &MBB) const {
68  llvm_unreachable("TODO: implement emitEpilogue");
69}
70
71void WebAssemblyFrameLowering::processFunctionBeforeCalleeSavedScan(
72    MachineFunction &MF, RegScavenger *RS) const {
73  llvm_unreachable("TODO: implement processFunctionBeforeCalleeSavedScan");
74}
75