llvm-project/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
Reid Kleckner 984dc4b9cd [WebAssembly] Create separation between MC and CodeGen layers
Move WebAssemblyUtilities from Utils to the CodeGen library. It
primarily deals in MIR layer types, so it really lives in the CodeGen
library.

Move a variety of other things around to try create better separation.

See issue #64166 for more info on layering.

Move llvm/include/CodeGen/WasmAddressSpaces.h back to
llvm/lib/Target/WebAssembly/Utils.

Differential Revision: https://reviews.llvm.org/D156472
2023-08-18 14:08:37 -07:00

234 lines
8.3 KiB
C++

//===-- WebAssemblyInstrInfo.cpp - WebAssembly Instruction Information ----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file contains the WebAssembly implementation of the
/// TargetInstrInfo class.
///
//===----------------------------------------------------------------------===//
#include "WebAssemblyInstrInfo.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "WebAssembly.h"
#include "WebAssemblyMachineFunctionInfo.h"
#include "WebAssemblySubtarget.h"
#include "WebAssemblyUtilities.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
using namespace llvm;
#define DEBUG_TYPE "wasm-instr-info"
#define GET_INSTRINFO_CTOR_DTOR
#include "WebAssemblyGenInstrInfo.inc"
// defines WebAssembly::getNamedOperandIdx
#define GET_INSTRINFO_NAMED_OPS
#include "WebAssemblyGenInstrInfo.inc"
WebAssemblyInstrInfo::WebAssemblyInstrInfo(const WebAssemblySubtarget &STI)
: WebAssemblyGenInstrInfo(WebAssembly::ADJCALLSTACKDOWN,
WebAssembly::ADJCALLSTACKUP,
WebAssembly::CATCHRET),
RI(STI.getTargetTriple()) {}
bool WebAssemblyInstrInfo::isReallyTriviallyReMaterializable(
const MachineInstr &MI) const {
switch (MI.getOpcode()) {
case WebAssembly::CONST_I32:
case WebAssembly::CONST_I64:
case WebAssembly::CONST_F32:
case WebAssembly::CONST_F64:
// TargetInstrInfo::isReallyTriviallyReMaterializable misses these
// because of the ARGUMENTS implicit def, so we manualy override it here.
return true;
default:
return TargetInstrInfo::isReallyTriviallyReMaterializable(MI);
}
}
void WebAssemblyInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
const DebugLoc &DL, MCRegister DestReg,
MCRegister SrcReg, bool KillSrc) const {
// This method is called by post-RA expansion, which expects only pregs to
// exist. However we need to handle both here.
auto &MRI = MBB.getParent()->getRegInfo();
const TargetRegisterClass *RC =
Register::isVirtualRegister(DestReg)
? MRI.getRegClass(DestReg)
: MRI.getTargetRegisterInfo()->getMinimalPhysRegClass(DestReg);
unsigned CopyOpcode = WebAssembly::getCopyOpcodeForRegClass(RC);
BuildMI(MBB, I, DL, get(CopyOpcode), DestReg)
.addReg(SrcReg, KillSrc ? RegState::Kill : 0);
}
MachineInstr *WebAssemblyInstrInfo::commuteInstructionImpl(
MachineInstr &MI, bool NewMI, unsigned OpIdx1, unsigned OpIdx2) const {
// If the operands are stackified, we can't reorder them.
WebAssemblyFunctionInfo &MFI =
*MI.getParent()->getParent()->getInfo<WebAssemblyFunctionInfo>();
if (MFI.isVRegStackified(MI.getOperand(OpIdx1).getReg()) ||
MFI.isVRegStackified(MI.getOperand(OpIdx2).getReg()))
return nullptr;
// Otherwise use the default implementation.
return TargetInstrInfo::commuteInstructionImpl(MI, NewMI, OpIdx1, OpIdx2);
}
// Branch analysis.
bool WebAssemblyInstrInfo::analyzeBranch(MachineBasicBlock &MBB,
MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool /*AllowModify*/) const {
const auto &MFI = *MBB.getParent()->getInfo<WebAssemblyFunctionInfo>();
// WebAssembly has control flow that doesn't have explicit branches or direct
// fallthrough (e.g. try/catch), which can't be modeled by analyzeBranch. It
// is created after CFGStackify.
if (MFI.isCFGStackified())
return true;
bool HaveCond = false;
for (MachineInstr &MI : MBB.terminators()) {
switch (MI.getOpcode()) {
default:
// Unhandled instruction; bail out.
return true;
case WebAssembly::BR_IF:
if (HaveCond)
return true;
Cond.push_back(MachineOperand::CreateImm(true));
Cond.push_back(MI.getOperand(1));
TBB = MI.getOperand(0).getMBB();
HaveCond = true;
break;
case WebAssembly::BR_UNLESS:
if (HaveCond)
return true;
Cond.push_back(MachineOperand::CreateImm(false));
Cond.push_back(MI.getOperand(1));
TBB = MI.getOperand(0).getMBB();
HaveCond = true;
break;
case WebAssembly::BR:
if (!HaveCond)
TBB = MI.getOperand(0).getMBB();
else
FBB = MI.getOperand(0).getMBB();
break;
}
if (MI.isBarrier())
break;
}
return false;
}
unsigned WebAssemblyInstrInfo::removeBranch(MachineBasicBlock &MBB,
int *BytesRemoved) const {
assert(!BytesRemoved && "code size not handled");
MachineBasicBlock::instr_iterator I = MBB.instr_end();
unsigned Count = 0;
while (I != MBB.instr_begin()) {
--I;
if (I->isDebugInstr())
continue;
if (!I->isTerminator())
break;
// Remove the branch.
I->eraseFromParent();
I = MBB.instr_end();
++Count;
}
return Count;
}
unsigned WebAssemblyInstrInfo::insertBranch(
MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB,
ArrayRef<MachineOperand> Cond, const DebugLoc &DL, int *BytesAdded) const {
assert(!BytesAdded && "code size not handled");
if (Cond.empty()) {
if (!TBB)
return 0;
BuildMI(&MBB, DL, get(WebAssembly::BR)).addMBB(TBB);
return 1;
}
assert(Cond.size() == 2 && "Expected a flag and a successor block");
if (Cond[0].getImm())
BuildMI(&MBB, DL, get(WebAssembly::BR_IF)).addMBB(TBB).add(Cond[1]);
else
BuildMI(&MBB, DL, get(WebAssembly::BR_UNLESS)).addMBB(TBB).add(Cond[1]);
if (!FBB)
return 1;
BuildMI(&MBB, DL, get(WebAssembly::BR)).addMBB(FBB);
return 2;
}
bool WebAssemblyInstrInfo::reverseBranchCondition(
SmallVectorImpl<MachineOperand> &Cond) const {
assert(Cond.size() == 2 && "Expected a flag and a condition expression");
Cond.front() = MachineOperand::CreateImm(!Cond.front().getImm());
return false;
}
ArrayRef<std::pair<int, const char *>>
WebAssemblyInstrInfo::getSerializableTargetIndices() const {
static const std::pair<int, const char *> TargetIndices[] = {
{WebAssembly::TI_LOCAL, "wasm-local"},
{WebAssembly::TI_GLOBAL_FIXED, "wasm-global-fixed"},
{WebAssembly::TI_OPERAND_STACK, "wasm-operand-stack"},
{WebAssembly::TI_GLOBAL_RELOC, "wasm-global-reloc"},
{WebAssembly::TI_LOCAL_INDIRECT, "wasm-local-indirect"}};
return ArrayRef(TargetIndices);
}
const MachineOperand &
WebAssemblyInstrInfo::getCalleeOperand(const MachineInstr &MI) const {
return WebAssembly::getCalleeOp(MI);
}
// This returns true when the instruction defines a value of a TargetIndex
// operand that can be tracked by offsets. For Wasm, this returns true for only
// local.set/local.tees. This is currently used by LiveDebugValues analysis.
//
// These are not included:
// - In theory we need to add global.set here too, but we don't have global
// indices at this point because they are relocatable and we address them by
// names until linking, so we don't have 'offsets' (which are used to store
// local/global indices) to deal with in LiveDebugValues. And we don't
// associate debug info in values in globals anyway.
// - All other value-producing instructions, i.e. instructions with defs, can
// define values in the Wasm stack, which is represented by TI_OPERAND_STACK
// TargetIndex. But they don't have offset info within the instruction itself,
// and debug info analysis for them is handled separately in
// WebAssemblyDebugFixup pass, so we don't worry about them here.
bool WebAssemblyInstrInfo::isExplicitTargetIndexDef(const MachineInstr &MI,
int &Index,
int64_t &Offset) const {
unsigned Opc = MI.getOpcode();
if (WebAssembly::isLocalSet(Opc) || WebAssembly::isLocalTee(Opc)) {
Index = WebAssembly::TI_LOCAL;
Offset = MI.explicit_uses().begin()->getImm();
return true;
}
return false;
}