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llvm-mirror/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
Wouter van Oortmerssen 538b137e0b [WebAssembly] Added initial type checker to MC Assembler 
This to protect against non-sensical instruction sequences being assembled,
which would either cause asserts/crashes further down, or a Wasm module being output that doesn't validate.

Unlike a validator, this type checker is able to give type-errors as part of the parsing process, which makes the assembler much friendlier to be used by humans writing manual input.

Because the MC system is single pass (instructions aren't even stored in MC format, they are directly output) the type checker has to be single pass as well, which means that from now on .globaltype and .functype decls must come before their use. An extra pass is added to Codegen to collect information for this purpose, since AsmPrinter is normally single pass / streaming as well, and would otherwise generate this information on the fly.

A `-no-type-check` flag was added to llvm-mc (and any other tools that take asm input) that surpresses type errors, as a quick escape hatch for tests that were not intended to be type correct.

This is a first version of the type checker that ignores control flow, i.e. it checks that types are correct along the linear path, but not the branch path. This will still catch most errors. Branch checking could be added in the future.

Differential Revision: https://reviews.llvm.org/D104945
2021-07-09 14:07:25 -07:00

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//===-- WebAssemblyAsmPrinter.cpp - WebAssembly LLVM assembly writer ------===//
//
// 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 a printer that converts from our internal
/// representation of machine-dependent LLVM code to the WebAssembly assembly
/// language.
///
//===----------------------------------------------------------------------===//
#include "WebAssemblyAsmPrinter.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "MCTargetDesc/WebAssemblyTargetStreamer.h"
#include "TargetInfo/WebAssemblyTargetInfo.h"
#include "Utils/WebAssemblyTypeUtilities.h"
#include "Utils/WebAssemblyUtilities.h"
#include "WebAssembly.h"
#include "WebAssemblyMCInstLower.h"
#include "WebAssemblyMachineFunctionInfo.h"
#include "WebAssemblyRegisterInfo.h"
#include "WebAssemblyRuntimeLibcallSignatures.h"
#include "WebAssemblyTargetMachine.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/BinaryFormat/Wasm.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Metadata.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSectionWasm.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolWasm.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "asm-printer"
extern cl::opt<bool> WasmKeepRegisters;
extern cl::opt<bool> EnableEmException;
extern cl::opt<bool> EnableEmSjLj;
//===----------------------------------------------------------------------===//
// Helpers.
//===----------------------------------------------------------------------===//
MVT WebAssemblyAsmPrinter::getRegType(unsigned RegNo) const {
const TargetRegisterInfo *TRI = Subtarget->getRegisterInfo();
const TargetRegisterClass *TRC = MRI->getRegClass(RegNo);
for (MVT T : {MVT::i32, MVT::i64, MVT::f32, MVT::f64, MVT::v16i8, MVT::v8i16,
MVT::v4i32, MVT::v2i64, MVT::v4f32, MVT::v2f64})
if (TRI->isTypeLegalForClass(*TRC, T))
return T;
LLVM_DEBUG(errs() << "Unknown type for register number: " << RegNo);
llvm_unreachable("Unknown register type");
return MVT::Other;
}
std::string WebAssemblyAsmPrinter::regToString(const MachineOperand &MO) {
Register RegNo = MO.getReg();
assert(Register::isVirtualRegister(RegNo) &&
"Unlowered physical register encountered during assembly printing");
assert(!MFI->isVRegStackified(RegNo));
unsigned WAReg = MFI->getWAReg(RegNo);
assert(WAReg != WebAssemblyFunctionInfo::UnusedReg);
return '$' + utostr(WAReg);
}
WebAssemblyTargetStreamer *WebAssemblyAsmPrinter::getTargetStreamer() {
MCTargetStreamer *TS = OutStreamer->getTargetStreamer();
return static_cast<WebAssemblyTargetStreamer *>(TS);
}
// Emscripten exception handling helpers
//
// This converts invoke names generated by LowerEmscriptenEHSjLj to real names
// that are expected by JavaScript glue code. The invoke names generated by
// Emscripten JS glue code are based on their argument and return types; for
// example, for a function that takes an i32 and returns nothing, it is
// 'invoke_vi'. But the format of invoke generated by LowerEmscriptenEHSjLj pass
// contains a mangled string generated from their IR types, for example,
// "__invoke_void_%struct.mystruct*_int", because final wasm types are not
// available in the IR pass. So we convert those names to the form that
// Emscripten JS code expects.
//
// Refer to LowerEmscriptenEHSjLj pass for more details.
// Returns true if the given function name is an invoke name generated by
// LowerEmscriptenEHSjLj pass.
static bool isEmscriptenInvokeName(StringRef Name) {
if (Name.front() == '"' && Name.back() == '"')
Name = Name.substr(1, Name.size() - 2);
return Name.startswith("__invoke_");
}
// Returns a character that represents the given wasm value type in invoke
// signatures.
static char getInvokeSig(wasm::ValType VT) {
switch (VT) {
case wasm::ValType::I32:
return 'i';
case wasm::ValType::I64:
return 'j';
case wasm::ValType::F32:
return 'f';
case wasm::ValType::F64:
return 'd';
case wasm::ValType::V128:
return 'V';
case wasm::ValType::FUNCREF:
return 'F';
case wasm::ValType::EXTERNREF:
return 'X';
}
llvm_unreachable("Unhandled wasm::ValType enum");
}
// Given the wasm signature, generate the invoke name in the format JS glue code
// expects.
static std::string getEmscriptenInvokeSymbolName(wasm::WasmSignature *Sig) {
assert(Sig->Returns.size() <= 1);
std::string Ret = "invoke_";
if (!Sig->Returns.empty())
for (auto VT : Sig->Returns)
Ret += getInvokeSig(VT);
else
Ret += 'v';
// Invokes' first argument is a pointer to the original function, so skip it
for (unsigned I = 1, E = Sig->Params.size(); I < E; I++)
Ret += getInvokeSig(Sig->Params[I]);
return Ret;
}
//===----------------------------------------------------------------------===//
// WebAssemblyAsmPrinter Implementation.
//===----------------------------------------------------------------------===//
MCSymbolWasm *WebAssemblyAsmPrinter::getMCSymbolForFunction(
const Function *F, bool EnableEmEH, wasm::WasmSignature *Sig,
bool &InvokeDetected) {
MCSymbolWasm *WasmSym = nullptr;
if (EnableEmEH && isEmscriptenInvokeName(F->getName())) {
assert(Sig);
InvokeDetected = true;
if (Sig->Returns.size() > 1) {
std::string Msg =
"Emscripten EH/SjLj does not support multivalue returns: " +
std::string(F->getName()) + ": " +
WebAssembly::signatureToString(Sig);
report_fatal_error(Msg);
}
WasmSym = cast<MCSymbolWasm>(
GetExternalSymbolSymbol(getEmscriptenInvokeSymbolName(Sig)));
} else {
WasmSym = cast<MCSymbolWasm>(getSymbol(F));
}
return WasmSym;
}
void WebAssemblyAsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
if (!WebAssembly::isWasmVarAddressSpace(GV->getAddressSpace())) {
AsmPrinter::emitGlobalVariable(GV);
return;
}
assert(!GV->isThreadLocal());
MCSymbolWasm *Sym = cast<MCSymbolWasm>(getSymbol(GV));
if (!Sym->getType()) {
const WebAssemblyTargetLowering &TLI = *Subtarget->getTargetLowering();
SmallVector<EVT, 1> VTs;
ComputeValueVTs(TLI, GV->getParent()->getDataLayout(), GV->getValueType(),
VTs);
if (VTs.size() != 1 ||
TLI.getNumRegisters(GV->getParent()->getContext(), VTs[0]) != 1)
report_fatal_error("Aggregate globals not yet implemented");
MVT VT = TLI.getRegisterType(GV->getParent()->getContext(), VTs[0]);
bool Mutable = true;
wasm::ValType Type = WebAssembly::toValType(VT);
Sym->setType(wasm::WASM_SYMBOL_TYPE_GLOBAL);
Sym->setGlobalType(wasm::WasmGlobalType{uint8_t(Type), Mutable});
}
emitVisibility(Sym, GV->getVisibility(), !GV->isDeclaration());
if (GV->hasInitializer()) {
assert(getSymbolPreferLocal(*GV) == Sym);
emitLinkage(GV, Sym);
getTargetStreamer()->emitGlobalType(Sym);
OutStreamer->emitLabel(Sym);
// TODO: Actually emit the initializer value. Otherwise the global has the
// default value for its type (0, ref.null, etc).
OutStreamer->AddBlankLine();
}
}
MCSymbol *WebAssemblyAsmPrinter::getOrCreateWasmSymbol(StringRef Name) {
auto *WasmSym = cast<MCSymbolWasm>(GetExternalSymbolSymbol(Name));
// May be called multiple times, so early out.
if (WasmSym->getType().hasValue())
return WasmSym;
const WebAssemblySubtarget &Subtarget = getSubtarget();
// Except for certain known symbols, all symbols used by CodeGen are
// functions. It's OK to hardcode knowledge of specific symbols here; this
// method is precisely there for fetching the signatures of known
// Clang-provided symbols.
if (Name == "__stack_pointer" || Name == "__tls_base" ||
Name == "__memory_base" || Name == "__table_base" ||
Name == "__tls_size" || Name == "__tls_align") {
bool Mutable =
Name == "__stack_pointer" || Name == "__tls_base";
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_GLOBAL);
WasmSym->setGlobalType(wasm::WasmGlobalType{
uint8_t(Subtarget.hasAddr64() ? wasm::WASM_TYPE_I64
: wasm::WASM_TYPE_I32),
Mutable});
return WasmSym;
}
SmallVector<wasm::ValType, 4> Returns;
SmallVector<wasm::ValType, 4> Params;
if (Name == "__cpp_exception") {
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_TAG);
// We can't confirm its signature index for now because there can be
// imported exceptions. Set it to be 0 for now.
WasmSym->setTagType(
{wasm::WASM_TAG_ATTRIBUTE_EXCEPTION, /* SigIndex */ 0});
// We may have multiple C++ compilation units to be linked together, each of
// which defines the exception symbol. To resolve them, we declare them as
// weak.
WasmSym->setWeak(true);
WasmSym->setExternal(true);
// All C++ exceptions are assumed to have a single i32 (for wasm32) or i64
// (for wasm64) param type and void return type. The reaon is, all C++
// exception values are pointers, and to share the type section with
// functions, exceptions are assumed to have void return type.
Params.push_back(Subtarget.hasAddr64() ? wasm::ValType::I64
: wasm::ValType::I32);
} else { // Function symbols
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
getLibcallSignature(Subtarget, Name, Returns, Params);
}
auto Signature = std::make_unique<wasm::WasmSignature>(std::move(Returns),
std::move(Params));
WasmSym->setSignature(Signature.get());
addSignature(std::move(Signature));
return WasmSym;
}
void WebAssemblyAsmPrinter::emitExternalDecls(const Module &M) {
if (signaturesEmitted)
return;
signaturesEmitted = true;
// Normally symbols for globals get discovered as the MI gets lowered,
// but we need to know about them ahead of time.
MachineModuleInfoWasm &MMIW = MMI->getObjFileInfo<MachineModuleInfoWasm>();
for (const auto &Name : MMIW.MachineSymbolsUsed) {
getOrCreateWasmSymbol(Name.getKey());
}
for (auto &It : OutContext.getSymbols()) {
// Emit .globaltype, .tagtype, or .tabletype declarations.
auto Sym = cast<MCSymbolWasm>(It.getValue());
if (Sym->getType() == wasm::WASM_SYMBOL_TYPE_GLOBAL) {
// .globaltype already handled by emitGlobalVariable for defined
// variables; here we make sure the types of external wasm globals get
// written to the file.
if (Sym->isUndefined())
getTargetStreamer()->emitGlobalType(Sym);
} else if (Sym->getType() == wasm::WASM_SYMBOL_TYPE_TAG)
getTargetStreamer()->emitTagType(Sym);
else if (Sym->getType() == wasm::WASM_SYMBOL_TYPE_TABLE)
getTargetStreamer()->emitTableType(Sym);
}
DenseSet<MCSymbol *> InvokeSymbols;
for (const auto &F : M) {
if (F.isIntrinsic())
continue;
// Emit function type info for all undefined functions
if (F.isDeclarationForLinker()) {
SmallVector<MVT, 4> Results;
SmallVector<MVT, 4> Params;
computeSignatureVTs(F.getFunctionType(), &F, F, TM, Params, Results);
// At this point these MCSymbols may or may not have been created already
// and thus also contain a signature, but we need to get the signature
// anyway here in case it is an invoke that has not yet been created. We
// will discard it later if it turns out not to be necessary.
auto Signature = signatureFromMVTs(Results, Params);
bool InvokeDetected = false;
auto *Sym = getMCSymbolForFunction(&F, EnableEmException || EnableEmSjLj,
Signature.get(), InvokeDetected);
// Multiple functions can be mapped to the same invoke symbol. For
// example, two IR functions '__invoke_void_i8*' and '__invoke_void_i32'
// are both mapped to '__invoke_vi'. We keep them in a set once we emit an
// Emscripten EH symbol so we don't emit the same symbol twice.
if (InvokeDetected && !InvokeSymbols.insert(Sym).second)
continue;
Sym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
if (!Sym->getSignature()) {
Sym->setSignature(Signature.get());
addSignature(std::move(Signature));
} else {
// This symbol has already been created and had a signature. Discard it.
Signature.reset();
}
getTargetStreamer()->emitFunctionType(Sym);
if (F.hasFnAttribute("wasm-import-module")) {
StringRef Name =
F.getFnAttribute("wasm-import-module").getValueAsString();
Sym->setImportModule(storeName(Name));
getTargetStreamer()->emitImportModule(Sym, Name);
}
if (F.hasFnAttribute("wasm-import-name")) {
// If this is a converted Emscripten EH/SjLj symbol, we shouldn't use
// the original function name but the converted symbol name.
StringRef Name =
InvokeDetected
? Sym->getName()
: F.getFnAttribute("wasm-import-name").getValueAsString();
Sym->setImportName(storeName(Name));
getTargetStreamer()->emitImportName(Sym, Name);
}
}
if (F.hasFnAttribute("wasm-export-name")) {
auto *Sym = cast<MCSymbolWasm>(getSymbol(&F));
StringRef Name = F.getFnAttribute("wasm-export-name").getValueAsString();
Sym->setExportName(storeName(Name));
getTargetStreamer()->emitExportName(Sym, Name);
}
}
}
void WebAssemblyAsmPrinter::emitEndOfAsmFile(Module &M) {
emitExternalDecls(M);
// When a function's address is taken, a TABLE_INDEX relocation is emitted
// against the function symbol at the use site. However the relocation
// doesn't explicitly refer to the table. In the future we may want to
// define a new kind of reloc against both the function and the table, so
// that the linker can see that the function symbol keeps the table alive,
// but for now manually mark the table as live.
for (const auto &F : M) {
if (!F.isIntrinsic() && F.hasAddressTaken()) {
MCSymbolWasm *FunctionTable =
WebAssembly::getOrCreateFunctionTableSymbol(OutContext, Subtarget);
OutStreamer->emitSymbolAttribute(FunctionTable, MCSA_NoDeadStrip);
break;
}
}
for (const auto &G : M.globals()) {
if (!G.hasInitializer() && G.hasExternalLinkage() &&
!WebAssembly::isWasmVarAddressSpace(G.getAddressSpace()) &&
G.getValueType()->isSized()) {
uint16_t Size = M.getDataLayout().getTypeAllocSize(G.getValueType());
OutStreamer->emitELFSize(getSymbol(&G),
MCConstantExpr::create(Size, OutContext));
}
}
if (const NamedMDNode *Named = M.getNamedMetadata("wasm.custom_sections")) {
for (const Metadata *MD : Named->operands()) {
const auto *Tuple = dyn_cast<MDTuple>(MD);
if (!Tuple || Tuple->getNumOperands() != 2)
continue;
const MDString *Name = dyn_cast<MDString>(Tuple->getOperand(0));
const MDString *Contents = dyn_cast<MDString>(Tuple->getOperand(1));
if (!Name || !Contents)
continue;
OutStreamer->PushSection();
std::string SectionName = (".custom_section." + Name->getString()).str();
MCSectionWasm *MySection =
OutContext.getWasmSection(SectionName, SectionKind::getMetadata());
OutStreamer->SwitchSection(MySection);
OutStreamer->emitBytes(Contents->getString());
OutStreamer->PopSection();
}
}
EmitProducerInfo(M);
EmitTargetFeatures(M);
}
void WebAssemblyAsmPrinter::EmitProducerInfo(Module &M) {
llvm::SmallVector<std::pair<std::string, std::string>, 4> Languages;
if (const NamedMDNode *Debug = M.getNamedMetadata("llvm.dbg.cu")) {
llvm::SmallSet<StringRef, 4> SeenLanguages;
for (size_t I = 0, E = Debug->getNumOperands(); I < E; ++I) {
const auto *CU = cast<DICompileUnit>(Debug->getOperand(I));
StringRef Language = dwarf::LanguageString(CU->getSourceLanguage());
Language.consume_front("DW_LANG_");
if (SeenLanguages.insert(Language).second)
Languages.emplace_back(Language.str(), "");
}
}
llvm::SmallVector<std::pair<std::string, std::string>, 4> Tools;
if (const NamedMDNode *Ident = M.getNamedMetadata("llvm.ident")) {
llvm::SmallSet<StringRef, 4> SeenTools;
for (size_t I = 0, E = Ident->getNumOperands(); I < E; ++I) {
const auto *S = cast<MDString>(Ident->getOperand(I)->getOperand(0));
std::pair<StringRef, StringRef> Field = S->getString().split("version");
StringRef Name = Field.first.trim();
StringRef Version = Field.second.trim();
if (SeenTools.insert(Name).second)
Tools.emplace_back(Name.str(), Version.str());
}
}
int FieldCount = int(!Languages.empty()) + int(!Tools.empty());
if (FieldCount != 0) {
MCSectionWasm *Producers = OutContext.getWasmSection(
".custom_section.producers", SectionKind::getMetadata());
OutStreamer->PushSection();
OutStreamer->SwitchSection(Producers);
OutStreamer->emitULEB128IntValue(FieldCount);
for (auto &Producers : {std::make_pair("language", &Languages),
std::make_pair("processed-by", &Tools)}) {
if (Producers.second->empty())
continue;
OutStreamer->emitULEB128IntValue(strlen(Producers.first));
OutStreamer->emitBytes(Producers.first);
OutStreamer->emitULEB128IntValue(Producers.second->size());
for (auto &Producer : *Producers.second) {
OutStreamer->emitULEB128IntValue(Producer.first.size());
OutStreamer->emitBytes(Producer.first);
OutStreamer->emitULEB128IntValue(Producer.second.size());
OutStreamer->emitBytes(Producer.second);
}
}
OutStreamer->PopSection();
}
}
void WebAssemblyAsmPrinter::EmitTargetFeatures(Module &M) {
struct FeatureEntry {
uint8_t Prefix;
std::string Name;
};
// Read target features and linkage policies from module metadata
SmallVector<FeatureEntry, 4> EmittedFeatures;
auto EmitFeature = [&](std::string Feature) {
std::string MDKey = (StringRef("wasm-feature-") + Feature).str();
Metadata *Policy = M.getModuleFlag(MDKey);
if (Policy == nullptr)
return;
FeatureEntry Entry;
Entry.Prefix = 0;
Entry.Name = Feature;
if (auto *MD = cast<ConstantAsMetadata>(Policy))
if (auto *I = cast<ConstantInt>(MD->getValue()))
Entry.Prefix = I->getZExtValue();
// Silently ignore invalid metadata
if (Entry.Prefix != wasm::WASM_FEATURE_PREFIX_USED &&
Entry.Prefix != wasm::WASM_FEATURE_PREFIX_REQUIRED &&
Entry.Prefix != wasm::WASM_FEATURE_PREFIX_DISALLOWED)
return;
EmittedFeatures.push_back(Entry);
};
for (const SubtargetFeatureKV &KV : WebAssemblyFeatureKV) {
EmitFeature(KV.Key);
}
// This pseudo-feature tells the linker whether shared memory would be safe
EmitFeature("shared-mem");
if (EmittedFeatures.size() == 0)
return;
// Emit features and linkage policies into the "target_features" section
MCSectionWasm *FeaturesSection = OutContext.getWasmSection(
".custom_section.target_features", SectionKind::getMetadata());
OutStreamer->PushSection();
OutStreamer->SwitchSection(FeaturesSection);
OutStreamer->emitULEB128IntValue(EmittedFeatures.size());
for (auto &F : EmittedFeatures) {
OutStreamer->emitIntValue(F.Prefix, 1);
OutStreamer->emitULEB128IntValue(F.Name.size());
OutStreamer->emitBytes(F.Name);
}
OutStreamer->PopSection();
}
void WebAssemblyAsmPrinter::emitConstantPool() {
assert(MF->getConstantPool()->getConstants().empty() &&
"WebAssembly disables constant pools");
}
void WebAssemblyAsmPrinter::emitJumpTableInfo() {
// Nothing to do; jump tables are incorporated into the instruction stream.
}
void WebAssemblyAsmPrinter::emitLinkage(const GlobalValue *GV, MCSymbol *Sym)
const {
AsmPrinter::emitLinkage(GV, Sym);
// This gets called before the function label and type are emitted.
// We use it to emit signatures of external functions.
// FIXME casts!
const_cast<WebAssemblyAsmPrinter *>(this)
->emitExternalDecls(*MMI->getModule());
}
void WebAssemblyAsmPrinter::emitFunctionBodyStart() {
const Function &F = MF->getFunction();
SmallVector<MVT, 1> ResultVTs;
SmallVector<MVT, 4> ParamVTs;
computeSignatureVTs(F.getFunctionType(), &F, F, TM, ParamVTs, ResultVTs);
auto Signature = signatureFromMVTs(ResultVTs, ParamVTs);
auto *WasmSym = cast<MCSymbolWasm>(CurrentFnSym);
WasmSym->setSignature(Signature.get());
addSignature(std::move(Signature));
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
getTargetStreamer()->emitFunctionType(WasmSym);
// Emit the function index.
if (MDNode *Idx = F.getMetadata("wasm.index")) {
assert(Idx->getNumOperands() == 1);
getTargetStreamer()->emitIndIdx(AsmPrinter::lowerConstant(
cast<ConstantAsMetadata>(Idx->getOperand(0))->getValue()));
}
SmallVector<wasm::ValType, 16> Locals;
valTypesFromMVTs(MFI->getLocals(), Locals);
getTargetStreamer()->emitLocal(Locals);
AsmPrinter::emitFunctionBodyStart();
}
void WebAssemblyAsmPrinter::emitInstruction(const MachineInstr *MI) {
LLVM_DEBUG(dbgs() << "EmitInstruction: " << *MI << '\n');
switch (MI->getOpcode()) {
case WebAssembly::ARGUMENT_i32:
case WebAssembly::ARGUMENT_i32_S:
case WebAssembly::ARGUMENT_i64:
case WebAssembly::ARGUMENT_i64_S:
case WebAssembly::ARGUMENT_f32:
case WebAssembly::ARGUMENT_f32_S:
case WebAssembly::ARGUMENT_f64:
case WebAssembly::ARGUMENT_f64_S:
case WebAssembly::ARGUMENT_v16i8:
case WebAssembly::ARGUMENT_v16i8_S:
case WebAssembly::ARGUMENT_v8i16:
case WebAssembly::ARGUMENT_v8i16_S:
case WebAssembly::ARGUMENT_v4i32:
case WebAssembly::ARGUMENT_v4i32_S:
case WebAssembly::ARGUMENT_v2i64:
case WebAssembly::ARGUMENT_v2i64_S:
case WebAssembly::ARGUMENT_v4f32:
case WebAssembly::ARGUMENT_v4f32_S:
case WebAssembly::ARGUMENT_v2f64:
case WebAssembly::ARGUMENT_v2f64_S:
// These represent values which are live into the function entry, so there's
// no instruction to emit.
break;
case WebAssembly::FALLTHROUGH_RETURN: {
// These instructions represent the implicit return at the end of a
// function body.
if (isVerbose()) {
OutStreamer->AddComment("fallthrough-return");
OutStreamer->AddBlankLine();
}
break;
}
case WebAssembly::COMPILER_FENCE:
// This is a compiler barrier that prevents instruction reordering during
// backend compilation, and should not be emitted.
break;
default: {
WebAssemblyMCInstLower MCInstLowering(OutContext, *this);
MCInst TmpInst;
MCInstLowering.lower(MI, TmpInst);
EmitToStreamer(*OutStreamer, TmpInst);
break;
}
}
}
bool WebAssemblyAsmPrinter::PrintAsmOperand(const MachineInstr *MI,
unsigned OpNo,
const char *ExtraCode,
raw_ostream &OS) {
// First try the generic code, which knows about modifiers like 'c' and 'n'.
if (!AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, OS))
return false;
if (!ExtraCode) {
const MachineOperand &MO = MI->getOperand(OpNo);
switch (MO.getType()) {
case MachineOperand::MO_Immediate:
OS << MO.getImm();
return false;
case MachineOperand::MO_Register:
// FIXME: only opcode that still contains registers, as required by
// MachineInstr::getDebugVariable().
assert(MI->getOpcode() == WebAssembly::INLINEASM);
OS << regToString(MO);
return false;
case MachineOperand::MO_GlobalAddress:
PrintSymbolOperand(MO, OS);
return false;
case MachineOperand::MO_ExternalSymbol:
GetExternalSymbolSymbol(MO.getSymbolName())->print(OS, MAI);
printOffset(MO.getOffset(), OS);
return false;
case MachineOperand::MO_MachineBasicBlock:
MO.getMBB()->getSymbol()->print(OS, MAI);
return false;
default:
break;
}
}
return true;
}
bool WebAssemblyAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
unsigned OpNo,
const char *ExtraCode,
raw_ostream &OS) {
// The current approach to inline asm is that "r" constraints are expressed
// as local indices, rather than values on the operand stack. This simplifies
// using "r" as it eliminates the need to push and pop the values in a
// particular order, however it also makes it impossible to have an "m"
// constraint. So we don't support it.
return AsmPrinter::PrintAsmMemoryOperand(MI, OpNo, ExtraCode, OS);
}
// Force static initialization.
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeWebAssemblyAsmPrinter() {
RegisterAsmPrinter<WebAssemblyAsmPrinter> X(getTheWebAssemblyTarget32());
RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(getTheWebAssemblyTarget64());
}
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