1 //=- WebAssemblyISelLowering.cpp - WebAssembly DAG Lowering Implementation -==//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// \brief This file implements the WebAssemblyTargetLowering class.
13 //===----------------------------------------------------------------------===//
15 #include "WebAssemblyISelLowering.h"
16 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
17 #include "WebAssemblyMachineFunctionInfo.h"
18 #include "WebAssemblySubtarget.h"
19 #include "WebAssemblyTargetMachine.h"
20 #include "WebAssemblyTargetObjectFile.h"
21 #include "llvm/CodeGen/Analysis.h"
22 #include "llvm/CodeGen/MachineRegisterInfo.h"
23 #include "llvm/CodeGen/SelectionDAG.h"
24 #include "llvm/IR/DiagnosticInfo.h"
25 #include "llvm/IR/DiagnosticPrinter.h"
26 #include "llvm/IR/Function.h"
27 #include "llvm/IR/Intrinsics.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/Debug.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/raw_ostream.h"
32 #include "llvm/Target/TargetOptions.h"
36 #define DEBUG_TYPE "wasm-lower"
39 // Diagnostic information for unimplemented or unsupported feature reporting.
40 // FIXME copied from BPF and AMDGPU.
41 class DiagnosticInfoUnsupported : public DiagnosticInfo {
43 // Debug location where this diagnostic is triggered.
45 const Twine &Description;
51 static int getKindID() {
53 KindID = llvm::getNextAvailablePluginDiagnosticKind();
58 DiagnosticInfoUnsupported(SDLoc DLoc, const Function &Fn, const Twine &Desc,
60 : DiagnosticInfo(getKindID(), DS_Error), DLoc(DLoc.getDebugLoc()),
61 Description(Desc), Fn(Fn), Value(Value) {}
63 void print(DiagnosticPrinter &DP) const override {
65 raw_string_ostream OS(Str);
68 auto DIL = DLoc.get();
69 StringRef Filename = DIL->getFilename();
70 unsigned Line = DIL->getLine();
71 unsigned Column = DIL->getColumn();
72 OS << Filename << ':' << Line << ':' << Column << ' ';
75 OS << "in function " << Fn.getName() << ' ' << *Fn.getFunctionType() << '\n'
84 static bool classof(const DiagnosticInfo *DI) {
85 return DI->getKind() == getKindID();
89 int DiagnosticInfoUnsupported::KindID = 0;
90 } // end anonymous namespace
92 WebAssemblyTargetLowering::WebAssemblyTargetLowering(
93 const TargetMachine &TM, const WebAssemblySubtarget &STI)
94 : TargetLowering(TM), Subtarget(&STI) {
95 // WebAssembly does not produce floating-point exceptions on normal floating
97 setHasFloatingPointExceptions(false);
98 // We don't know the microarchitecture here, so just reduce register pressure.
99 setSchedulingPreference(Sched::RegPressure);
100 // Tell ISel that we have a stack pointer.
101 setStackPointerRegisterToSaveRestore(
102 Subtarget->hasAddr64() ? WebAssembly::SP64 : WebAssembly::SP32);
103 // Set up the register classes.
104 addRegisterClass(MVT::i32, &WebAssembly::Int32RegClass);
105 addRegisterClass(MVT::i64, &WebAssembly::Int64RegClass);
106 addRegisterClass(MVT::f32, &WebAssembly::Float32RegClass);
107 addRegisterClass(MVT::f64, &WebAssembly::Float64RegClass);
108 // Compute derived properties from the register classes.
109 computeRegisterProperties(Subtarget->getRegisterInfo());
111 // FIXME: many setOperationAction are missing...
113 for (auto T : {MVT::f32, MVT::f64}) {
114 // Don't expand the floating-point types to constant pools.
115 setOperationAction(ISD::ConstantFP, T, Legal);
116 // Expand floating-point comparisons.
117 for (auto CC : {ISD::SETO, ISD::SETUO, ISD::SETUEQ, ISD::SETONE,
118 ISD::SETULT, ISD::SETULE, ISD::SETUGT, ISD::SETUGE})
119 setCondCodeAction(CC, T, Expand);
123 MVT WebAssemblyTargetLowering::getScalarShiftAmountTy(const DataLayout &DL,
125 return VT.getSimpleVT();
129 WebAssemblyTargetLowering::getTargetNodeName(unsigned Opcode) const {
130 switch (static_cast<WebAssemblyISD::NodeType>(Opcode)) {
131 case WebAssemblyISD::FIRST_NUMBER: break;
132 case WebAssemblyISD::RETURN: return "WebAssemblyISD::RETURN";
133 case WebAssemblyISD::ARGUMENT: return "WebAssemblyISD::ARGUMENT";
138 //===----------------------------------------------------------------------===//
139 // WebAssembly Lowering private implementation.
140 //===----------------------------------------------------------------------===//
142 //===----------------------------------------------------------------------===//
144 //===----------------------------------------------------------------------===//
146 static void fail(SDLoc DL, SelectionDAG &DAG, const char *msg) {
147 MachineFunction &MF = DAG.getMachineFunction();
148 DAG.getContext()->diagnose(
149 DiagnosticInfoUnsupported(DL, *MF.getFunction(), msg, SDValue()));
152 bool WebAssemblyTargetLowering::CanLowerReturn(
153 CallingConv::ID CallConv, MachineFunction &MF, bool IsVarArg,
154 const SmallVectorImpl<ISD::OutputArg> &Outs, LLVMContext &Context) const {
155 // WebAssembly can't currently handle returning tuples.
156 return Outs.size() <= 1;
159 SDValue WebAssemblyTargetLowering::LowerReturn(
160 SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
161 const SmallVectorImpl<ISD::OutputArg> &Outs,
162 const SmallVectorImpl<SDValue> &OutVals, SDLoc DL,
163 SelectionDAG &DAG) const {
165 assert(Outs.size() <= 1 && "WebAssembly can only return up to one value");
166 if (CallConv != CallingConv::C)
167 fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
169 fail(DL, DAG, "WebAssembly doesn't support varargs yet");
171 SmallVector<SDValue, 4> RetOps(1, Chain);
172 RetOps.append(OutVals.begin(), OutVals.end());
173 Chain = DAG.getNode(WebAssemblyISD::RETURN, DL, MVT::Other, RetOps);
178 SDValue WebAssemblyTargetLowering::LowerFormalArguments(
179 SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
180 const SmallVectorImpl<ISD::InputArg> &Ins, SDLoc DL, SelectionDAG &DAG,
181 SmallVectorImpl<SDValue> &InVals) const {
182 MachineFunction &MF = DAG.getMachineFunction();
184 if (CallConv != CallingConv::C)
185 fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
187 fail(DL, DAG, "WebAssembly doesn't support varargs yet");
188 if (MF.getFunction()->hasStructRetAttr())
189 fail(DL, DAG, "WebAssembly doesn't support struct return yet");
192 for (const ISD::InputArg &In : Ins) {
193 if (In.Flags.isZExt())
194 fail(DL, DAG, "WebAssembly hasn't implemented zext arguments");
195 if (In.Flags.isSExt())
196 fail(DL, DAG, "WebAssembly hasn't implemented sext arguments");
197 if (In.Flags.isInReg())
198 fail(DL, DAG, "WebAssembly hasn't implemented inreg arguments");
199 if (In.Flags.isSRet())
200 fail(DL, DAG, "WebAssembly hasn't implemented sret arguments");
201 if (In.Flags.isByVal())
202 fail(DL, DAG, "WebAssembly hasn't implemented byval arguments");
203 if (In.Flags.isInAlloca())
204 fail(DL, DAG, "WebAssembly hasn't implemented inalloca arguments");
205 if (In.Flags.isNest())
206 fail(DL, DAG, "WebAssembly hasn't implemented nest arguments");
207 if (In.Flags.isReturned())
208 fail(DL, DAG, "WebAssembly hasn't implemented returned arguments");
209 if (In.Flags.isInConsecutiveRegs())
210 fail(DL, DAG, "WebAssembly hasn't implemented cons regs arguments");
211 if (In.Flags.isInConsecutiveRegsLast())
212 fail(DL, DAG, "WebAssembly hasn't implemented cons regs last arguments");
213 if (In.Flags.isSplit())
214 fail(DL, DAG, "WebAssembly hasn't implemented split arguments");
215 // FIXME Do something with In.getOrigAlign()?
218 ? DAG.getNode(WebAssemblyISD::ARGUMENT, DL, In.VT,
219 DAG.getTargetConstant(ArgNo, DL, MVT::i32))
220 : DAG.getNode(ISD::UNDEF, DL, In.VT));
227 //===----------------------------------------------------------------------===//
228 // Other Lowering Code
229 //===----------------------------------------------------------------------===//
231 //===----------------------------------------------------------------------===//
232 // WebAssembly Optimization Hooks
233 //===----------------------------------------------------------------------===//
235 MCSection *WebAssemblyTargetObjectFile::SelectSectionForGlobal(
236 const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
237 const TargetMachine &TM) const {
238 return getDataSection();