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//=- WebAssemblyISelLowering.cpp - WebAssembly DAG Lowering Implementation -==//
//
// 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 implements the WebAssemblyTargetLowering class.
///
//===----------------------------------------------------------------------===//
#include "WebAssemblyISelLowering.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "WebAssemblyMachineFunctionInfo.h"
#include "WebAssemblySubtarget.h"
#include "WebAssemblyTargetMachine.h"
#include "WebAssemblyTargetObjectFile.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
#define DEBUG_TYPE "wasm-lower"
namespace {
// Diagnostic information for unimplemented or unsupported feature reporting.
// FIXME copied from BPF and AMDGPU.
class DiagnosticInfoUnsupported : public DiagnosticInfo {
private:
// Debug location where this diagnostic is triggered.
DebugLoc DLoc;
const Twine &Description;
const Function &Fn;
SDValue Value;
static int KindID;
static int getKindID() {
if (KindID == 0)
KindID = llvm::getNextAvailablePluginDiagnosticKind();
return KindID;
}
public:
DiagnosticInfoUnsupported(SDLoc DLoc, const Function &Fn, const Twine &Desc,
SDValue Value)
: DiagnosticInfo(getKindID(), DS_Error), DLoc(DLoc.getDebugLoc()),
Description(Desc), Fn(Fn), Value(Value) {}
void print(DiagnosticPrinter &DP) const override {
std::string Str;
raw_string_ostream OS(Str);
if (DLoc) {
auto DIL = DLoc.get();
StringRef Filename = DIL->getFilename();
unsigned Line = DIL->getLine();
unsigned Column = DIL->getColumn();
OS << Filename << ':' << Line << ':' << Column << ' ';
}
OS << "in function " << Fn.getName() << ' ' << *Fn.getFunctionType() << '\n'
<< Description;
if (Value)
Value->print(OS);
OS << '\n';
OS.flush();
DP << Str;
}
static bool classof(const DiagnosticInfo *DI) {
return DI->getKind() == getKindID();
}
};
int DiagnosticInfoUnsupported::KindID = 0;
} // end anonymous namespace
WebAssemblyTargetLowering::WebAssemblyTargetLowering(
const TargetMachine &TM, const WebAssemblySubtarget &STI)
: TargetLowering(TM), Subtarget(&STI) {
// WebAssembly does not produce floating-point exceptions on normal floating
// point operations.
setHasFloatingPointExceptions(false);
// We don't know the microarchitecture here, so just reduce register pressure.
setSchedulingPreference(Sched::RegPressure);
// Tell ISel that we have a stack pointer.
setStackPointerRegisterToSaveRestore(
Subtarget->hasAddr64() ? WebAssembly::SP64 : WebAssembly::SP32);
// Set up the register classes.
addRegisterClass(MVT::i32, &WebAssembly::Int32RegClass);
addRegisterClass(MVT::i64, &WebAssembly::Int64RegClass);
addRegisterClass(MVT::f32, &WebAssembly::Float32RegClass);
addRegisterClass(MVT::f64, &WebAssembly::Float64RegClass);
// Compute derived properties from the register classes.
computeRegisterProperties(Subtarget->getRegisterInfo());
// FIXME: many setOperationAction are missing...
// Don't expand the following types to constant pools.
setOperationAction(ISD::ConstantFP, MVT::f32, Legal);
setOperationAction(ISD::ConstantFP, MVT::f64, Legal);
}
MVT WebAssemblyTargetLowering::getScalarShiftAmountTy(const DataLayout &DL,
EVT VT) const {
return VT.getSimpleVT();
}
const char *
WebAssemblyTargetLowering::getTargetNodeName(unsigned Opcode) const {
switch (static_cast<WebAssemblyISD::NodeType>(Opcode)) {
case WebAssemblyISD::FIRST_NUMBER: break;
case WebAssemblyISD::RETURN: return "WebAssemblyISD::RETURN";
case WebAssemblyISD::ARGUMENT: return "WebAssemblyISD::ARGUMENT";
}
return nullptr;
}
//===----------------------------------------------------------------------===//
// WebAssembly Lowering private implementation.
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// Lowering Code
//===----------------------------------------------------------------------===//
static void fail(SDLoc DL, SelectionDAG &DAG, const char *msg) {
MachineFunction &MF = DAG.getMachineFunction();
DAG.getContext()->diagnose(
DiagnosticInfoUnsupported(DL, *MF.getFunction(), msg, SDValue()));
}
bool WebAssemblyTargetLowering::CanLowerReturn(
CallingConv::ID CallConv, MachineFunction &MF, bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs, LLVMContext &Context) const {
// WebAssembly can't currently handle returning tuples.
return Outs.size() <= 1;
}
SDValue WebAssemblyTargetLowering::LowerReturn(
SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals, SDLoc DL,
SelectionDAG &DAG) const {
assert(Outs.size() <= 1 && "WebAssembly can only return up to one value");
if (CallConv != CallingConv::C)
fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
if (IsVarArg)
fail(DL, DAG, "WebAssembly doesn't support varargs yet");
SmallVector<SDValue, 4> RetOps(1, Chain);
RetOps.append(OutVals.begin(), OutVals.end());
Chain = DAG.getNode(WebAssemblyISD::RETURN, DL, MVT::Other, RetOps);
return Chain;
}
SDValue WebAssemblyTargetLowering::LowerFormalArguments(
SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins, SDLoc DL, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const {
MachineFunction &MF = DAG.getMachineFunction();
if (CallConv != CallingConv::C)
fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
if (IsVarArg)
fail(DL, DAG, "WebAssembly doesn't support varargs yet");
if (MF.getFunction()->hasStructRetAttr())
fail(DL, DAG, "WebAssembly doesn't support struct return yet");
unsigned ArgNo = 0;
for (const ISD::InputArg &In : Ins) {
if (In.Flags.isZExt())
fail(DL, DAG, "WebAssembly hasn't implemented zext arguments");
if (In.Flags.isSExt())
fail(DL, DAG, "WebAssembly hasn't implemented sext arguments");
if (In.Flags.isInReg())
fail(DL, DAG, "WebAssembly hasn't implemented inreg arguments");
if (In.Flags.isSRet())
fail(DL, DAG, "WebAssembly hasn't implemented sret arguments");
if (In.Flags.isByVal())
fail(DL, DAG, "WebAssembly hasn't implemented byval arguments");
if (In.Flags.isInAlloca())
fail(DL, DAG, "WebAssembly hasn't implemented inalloca arguments");
if (In.Flags.isNest())
fail(DL, DAG, "WebAssembly hasn't implemented nest arguments");
if (In.Flags.isReturned())
fail(DL, DAG, "WebAssembly hasn't implemented returned arguments");
if (In.Flags.isInConsecutiveRegs())
fail(DL, DAG, "WebAssembly hasn't implemented cons regs arguments");
if (In.Flags.isInConsecutiveRegsLast())
fail(DL, DAG, "WebAssembly hasn't implemented cons regs last arguments");
if (In.Flags.isSplit())
fail(DL, DAG, "WebAssembly hasn't implemented split arguments");
// FIXME Do something with In.getOrigAlign()?
InVals.push_back(
In.Used
? DAG.getNode(WebAssemblyISD::ARGUMENT, DL, In.VT,
DAG.getTargetConstant(ArgNo, DL, MVT::i32))
: DAG.getNode(ISD::UNDEF, DL, In.VT));
++ArgNo;
}
return Chain;
}
//===----------------------------------------------------------------------===//
// Other Lowering Code
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// WebAssembly Optimization Hooks
//===----------------------------------------------------------------------===//
MCSection *WebAssemblyTargetObjectFile::SelectSectionForGlobal(
const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const {
return getDataSection();
}
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