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https://github.com/RPCS3/llvm-mirror.git
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fcb1ac7304
Summary: This handles all load/store operations that WebAssembly defines, and handles those necessary for C++ such as i1. I left a FIXME for outstanding features which aren't required for now. Reviewers: sunfish Subscribers: jfb, llvm-commits, dschuff llvm-svn: 246500
389 lines
14 KiB
C++
389 lines
14 KiB
C++
//=- WebAssemblyISelLowering.cpp - WebAssembly DAG Lowering Implementation -==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief This file implements the WebAssemblyTargetLowering class.
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///
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//===----------------------------------------------------------------------===//
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#include "WebAssemblyISelLowering.h"
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#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
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#include "WebAssemblyMachineFunctionInfo.h"
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#include "WebAssemblySubtarget.h"
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#include "WebAssemblyTargetMachine.h"
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#include "WebAssemblyTargetObjectFile.h"
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#include "llvm/CodeGen/Analysis.h"
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#include "llvm/CodeGen/CallingConvLower.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/SelectionDAG.h"
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#include "llvm/IR/DiagnosticInfo.h"
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#include "llvm/IR/DiagnosticPrinter.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Intrinsics.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetOptions.h"
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using namespace llvm;
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#define DEBUG_TYPE "wasm-lower"
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namespace {
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// Diagnostic information for unimplemented or unsupported feature reporting.
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// FIXME copied from BPF and AMDGPU.
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class DiagnosticInfoUnsupported : public DiagnosticInfo {
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private:
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// Debug location where this diagnostic is triggered.
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DebugLoc DLoc;
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const Twine &Description;
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const Function &Fn;
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SDValue Value;
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static int KindID;
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static int getKindID() {
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if (KindID == 0)
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KindID = llvm::getNextAvailablePluginDiagnosticKind();
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return KindID;
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}
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public:
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DiagnosticInfoUnsupported(SDLoc DLoc, const Function &Fn, const Twine &Desc,
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SDValue Value)
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: DiagnosticInfo(getKindID(), DS_Error), DLoc(DLoc.getDebugLoc()),
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Description(Desc), Fn(Fn), Value(Value) {}
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void print(DiagnosticPrinter &DP) const override {
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std::string Str;
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raw_string_ostream OS(Str);
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if (DLoc) {
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auto DIL = DLoc.get();
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StringRef Filename = DIL->getFilename();
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unsigned Line = DIL->getLine();
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unsigned Column = DIL->getColumn();
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OS << Filename << ':' << Line << ':' << Column << ' ';
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}
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OS << "in function " << Fn.getName() << ' ' << *Fn.getFunctionType() << '\n'
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<< Description;
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if (Value)
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Value->print(OS);
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OS << '\n';
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OS.flush();
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DP << Str;
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}
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static bool classof(const DiagnosticInfo *DI) {
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return DI->getKind() == getKindID();
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}
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};
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int DiagnosticInfoUnsupported::KindID = 0;
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} // end anonymous namespace
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WebAssemblyTargetLowering::WebAssemblyTargetLowering(
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const TargetMachine &TM, const WebAssemblySubtarget &STI)
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: TargetLowering(TM), Subtarget(&STI) {
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auto MVTPtr = Subtarget->hasAddr64() ? MVT::i64 : MVT::i32;
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// Booleans always contain 0 or 1.
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setBooleanContents(ZeroOrOneBooleanContent);
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// WebAssembly does not produce floating-point exceptions on normal floating
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// point operations.
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setHasFloatingPointExceptions(false);
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// We don't know the microarchitecture here, so just reduce register pressure.
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setSchedulingPreference(Sched::RegPressure);
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// Tell ISel that we have a stack pointer.
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setStackPointerRegisterToSaveRestore(
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Subtarget->hasAddr64() ? WebAssembly::SP64 : WebAssembly::SP32);
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// Set up the register classes.
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addRegisterClass(MVT::i32, &WebAssembly::Int32RegClass);
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addRegisterClass(MVT::i64, &WebAssembly::Int64RegClass);
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addRegisterClass(MVT::f32, &WebAssembly::Float32RegClass);
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addRegisterClass(MVT::f64, &WebAssembly::Float64RegClass);
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// Compute derived properties from the register classes.
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computeRegisterProperties(Subtarget->getRegisterInfo());
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setOperationAction(ISD::GlobalAddress, MVTPtr, Custom);
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for (auto T : {MVT::f32, MVT::f64}) {
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// Don't expand the floating-point types to constant pools.
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setOperationAction(ISD::ConstantFP, T, Legal);
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// Expand floating-point comparisons.
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for (auto CC : {ISD::SETO, ISD::SETUO, ISD::SETUEQ, ISD::SETONE,
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ISD::SETULT, ISD::SETULE, ISD::SETUGT, ISD::SETUGE})
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setCondCodeAction(CC, T, Expand);
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// Expand floating-point library function operators.
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for (auto Op : {ISD::FSIN, ISD::FCOS, ISD::FSINCOS, ISD::FPOWI, ISD::FPOW})
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setOperationAction(Op, T, Expand);
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// Note supported floating-point library function operators that otherwise
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// default to expand.
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for (auto Op : {ISD::FCEIL, ISD::FFLOOR, ISD::FTRUNC, ISD::FNEARBYINT,
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ISD::FRINT})
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setOperationAction(Op, T, Legal);
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}
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for (auto T : {MVT::i32, MVT::i64}) {
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// Expand unavailable integer operations.
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for (auto Op : {ISD::BSWAP, ISD::ROTL, ISD::ROTR,
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ISD::SMUL_LOHI, ISD::UMUL_LOHI,
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ISD::MULHS, ISD::MULHU, ISD::SDIVREM, ISD::UDIVREM,
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ISD::SHL_PARTS, ISD::SRA_PARTS, ISD::SRL_PARTS,
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ISD::ADDC, ISD::ADDE, ISD::SUBC, ISD::SUBE}) {
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setOperationAction(Op, T, Expand);
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}
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}
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// As a special case, these operators use the type to mean the type to
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// sign-extend from.
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for (auto T : {MVT::i1, MVT::i8, MVT::i16})
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setOperationAction(ISD::SIGN_EXTEND_INREG, T, Expand);
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// Dynamic stack allocation: use the default expansion.
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setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
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setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
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setOperationAction(ISD::DYNAMIC_STACKALLOC, MVTPtr, Expand);
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// WebAssembly doesn't have:
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// - Floating-point extending loads.
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// - Floating-point truncating stores.
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// - i1 extending loads.
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setLoadExtAction(ISD::EXTLOAD, MVT::f32, MVT::f64, Expand);
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setTruncStoreAction(MVT::f64, MVT::f32, Expand);
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for (auto T : MVT::integer_valuetypes())
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for (auto Ext : {ISD::EXTLOAD, ISD::ZEXTLOAD, ISD::SEXTLOAD})
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setLoadExtAction(Ext, T, MVT::i1, Promote);
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}
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FastISel *WebAssemblyTargetLowering::createFastISel(
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FunctionLoweringInfo &FuncInfo, const TargetLibraryInfo *LibInfo) const {
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return WebAssembly::createFastISel(FuncInfo, LibInfo);
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}
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bool WebAssemblyTargetLowering::isOffsetFoldingLegal(
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const GlobalAddressSDNode *GA) const {
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// The WebAssembly target doesn't support folding offsets into global
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// addresses.
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return false;
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}
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MVT WebAssemblyTargetLowering::getScalarShiftAmountTy(const DataLayout &DL,
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EVT VT) const {
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return VT.getSimpleVT();
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}
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const char *
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WebAssemblyTargetLowering::getTargetNodeName(unsigned Opcode) const {
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switch (static_cast<WebAssemblyISD::NodeType>(Opcode)) {
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case WebAssemblyISD::FIRST_NUMBER:
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break;
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#define HANDLE_NODETYPE(NODE) \
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case WebAssemblyISD::NODE: \
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return "WebAssemblyISD::" #NODE;
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#include "WebAssemblyISD.def"
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#undef HANDLE_NODETYPE
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}
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return nullptr;
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}
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//===----------------------------------------------------------------------===//
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// WebAssembly Lowering private implementation.
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//===----------------------------------------------------------------------===//
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//===----------------------------------------------------------------------===//
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// Lowering Code
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//===----------------------------------------------------------------------===//
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static void fail(SDLoc DL, SelectionDAG &DAG, const char *msg) {
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MachineFunction &MF = DAG.getMachineFunction();
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DAG.getContext()->diagnose(
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DiagnosticInfoUnsupported(DL, *MF.getFunction(), msg, SDValue()));
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}
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SDValue
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WebAssemblyTargetLowering::LowerCall(CallLoweringInfo &CLI,
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SmallVectorImpl<SDValue> &InVals) const {
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SelectionDAG &DAG = CLI.DAG;
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SDLoc DL = CLI.DL;
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SDValue Chain = CLI.Chain;
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SDValue Callee = CLI.Callee;
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MachineFunction &MF = DAG.getMachineFunction();
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CallingConv::ID CallConv = CLI.CallConv;
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if (CallConv != CallingConv::C)
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fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
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if (CLI.IsTailCall || MF.getTarget().Options.GuaranteedTailCallOpt)
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fail(DL, DAG, "WebAssembly doesn't support tail call yet");
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if (CLI.IsPatchPoint)
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fail(DL, DAG, "WebAssembly doesn't support patch point yet");
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SmallVectorImpl<ISD::OutputArg> &Outs = CLI.Outs;
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SmallVectorImpl<SDValue> &OutVals = CLI.OutVals;
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bool IsStructRet = (Outs.empty()) ? false : Outs[0].Flags.isSRet();
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if (IsStructRet)
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fail(DL, DAG, "WebAssembly doesn't support struct return yet");
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if (Outs.size() > 1)
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fail(DL, DAG, "WebAssembly doesn't support more than 1 returned value yet");
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SmallVectorImpl<ISD::InputArg> &Ins = CLI.Ins;
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bool IsVarArg = CLI.IsVarArg;
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if (IsVarArg)
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fail(DL, DAG, "WebAssembly doesn't support varargs yet");
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// Analyze operands of the call, assigning locations to each operand.
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SmallVector<CCValAssign, 16> ArgLocs;
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CCState CCInfo(CallConv, IsVarArg, MF, ArgLocs, *DAG.getContext());
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unsigned NumBytes = CCInfo.getNextStackOffset();
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auto PtrVT = getPointerTy(MF.getDataLayout());
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auto Zero = DAG.getConstant(0, DL, PtrVT, true);
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auto NB = DAG.getConstant(NumBytes, DL, PtrVT, true);
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Chain = DAG.getCALLSEQ_START(Chain, NB, DL);
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SmallVector<SDValue, 16> Ops;
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Ops.push_back(Chain);
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Ops.push_back(Callee);
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Ops.append(OutVals.begin(), OutVals.end());
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SmallVector<EVT, 8> Tys;
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for (const auto &In : Ins)
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Tys.push_back(In.VT);
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Tys.push_back(MVT::Other);
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SDVTList TyList = DAG.getVTList(Tys);
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SDValue Res = DAG.getNode(WebAssemblyISD::CALL, DL, TyList, Ops);
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if (Ins.empty()) {
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Chain = Res;
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} else {
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InVals.push_back(Res);
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Chain = Res.getValue(1);
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}
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// FIXME: handle CLI.RetSExt and CLI.RetZExt?
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Chain = DAG.getCALLSEQ_END(Chain, NB, Zero, SDValue(), DL);
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return Chain;
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}
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bool WebAssemblyTargetLowering::CanLowerReturn(
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CallingConv::ID CallConv, MachineFunction &MF, bool IsVarArg,
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const SmallVectorImpl<ISD::OutputArg> &Outs, LLVMContext &Context) const {
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// WebAssembly can't currently handle returning tuples.
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return Outs.size() <= 1;
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}
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SDValue WebAssemblyTargetLowering::LowerReturn(
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SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
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const SmallVectorImpl<ISD::OutputArg> &Outs,
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const SmallVectorImpl<SDValue> &OutVals, SDLoc DL,
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SelectionDAG &DAG) const {
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assert(Outs.size() <= 1 && "WebAssembly can only return up to one value");
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if (CallConv != CallingConv::C)
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fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
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if (IsVarArg)
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fail(DL, DAG, "WebAssembly doesn't support varargs yet");
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SmallVector<SDValue, 4> RetOps(1, Chain);
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RetOps.append(OutVals.begin(), OutVals.end());
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Chain = DAG.getNode(WebAssemblyISD::RETURN, DL, MVT::Other, RetOps);
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return Chain;
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}
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SDValue WebAssemblyTargetLowering::LowerFormalArguments(
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SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
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const SmallVectorImpl<ISD::InputArg> &Ins, SDLoc DL, SelectionDAG &DAG,
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SmallVectorImpl<SDValue> &InVals) const {
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MachineFunction &MF = DAG.getMachineFunction();
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if (CallConv != CallingConv::C)
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fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
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if (IsVarArg)
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fail(DL, DAG, "WebAssembly doesn't support varargs yet");
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if (MF.getFunction()->hasStructRetAttr())
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fail(DL, DAG, "WebAssembly doesn't support struct return yet");
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unsigned ArgNo = 0;
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for (const ISD::InputArg &In : Ins) {
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if (In.Flags.isZExt())
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fail(DL, DAG, "WebAssembly hasn't implemented zext arguments");
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if (In.Flags.isSExt())
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fail(DL, DAG, "WebAssembly hasn't implemented sext arguments");
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if (In.Flags.isInReg())
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fail(DL, DAG, "WebAssembly hasn't implemented inreg arguments");
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if (In.Flags.isSRet())
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fail(DL, DAG, "WebAssembly hasn't implemented sret arguments");
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if (In.Flags.isByVal())
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fail(DL, DAG, "WebAssembly hasn't implemented byval arguments");
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if (In.Flags.isInAlloca())
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fail(DL, DAG, "WebAssembly hasn't implemented inalloca arguments");
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if (In.Flags.isNest())
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fail(DL, DAG, "WebAssembly hasn't implemented nest arguments");
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if (In.Flags.isReturned())
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fail(DL, DAG, "WebAssembly hasn't implemented returned arguments");
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if (In.Flags.isInConsecutiveRegs())
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fail(DL, DAG, "WebAssembly hasn't implemented cons regs arguments");
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if (In.Flags.isInConsecutiveRegsLast())
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fail(DL, DAG, "WebAssembly hasn't implemented cons regs last arguments");
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if (In.Flags.isSplit())
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fail(DL, DAG, "WebAssembly hasn't implemented split arguments");
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// FIXME Do something with In.getOrigAlign()?
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InVals.push_back(
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In.Used
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? DAG.getNode(WebAssemblyISD::ARGUMENT, DL, In.VT,
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DAG.getTargetConstant(ArgNo, DL, MVT::i32))
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: DAG.getNode(ISD::UNDEF, DL, In.VT));
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++ArgNo;
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}
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return Chain;
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}
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//===----------------------------------------------------------------------===//
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// Custom lowering hooks.
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//===----------------------------------------------------------------------===//
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SDValue WebAssemblyTargetLowering::LowerOperation(SDValue Op,
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SelectionDAG &DAG) const {
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switch (Op.getOpcode()) {
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default:
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llvm_unreachable("unimplemented operation lowering");
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return SDValue();
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case ISD::GlobalAddress:
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return LowerGlobalAddress(Op, DAG);
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}
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}
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SDValue WebAssemblyTargetLowering::LowerGlobalAddress(SDValue Op,
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SelectionDAG &DAG) const {
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SDLoc DL(Op);
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const auto *GA = cast<GlobalAddressSDNode>(Op);
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EVT VT = Op.getValueType();
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assert(GA->getOffset() == 0 &&
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"offsets on global addresses are forbidden by isOffsetFoldingLegal");
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assert(GA->getTargetFlags() == 0 && "WebAssembly doesn't set target flags");
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if (GA->getAddressSpace() != 0)
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fail(DL, DAG, "WebAssembly only expects the 0 address space");
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return DAG.getNode(WebAssemblyISD::Wrapper, DL, VT,
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DAG.getTargetGlobalAddress(GA->getGlobal(), DL, VT));
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}
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//===----------------------------------------------------------------------===//
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// WebAssembly Optimization Hooks
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//===----------------------------------------------------------------------===//
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MCSection *WebAssemblyTargetObjectFile::SelectSectionForGlobal(
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const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
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const TargetMachine &TM) const {
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return getDataSection();
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}
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