LLVM 17.0.0git
WebAssemblyAsmTypeCheck.cpp
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1//==- WebAssemblyAsmTypeCheck.cpp - Assembler for WebAssembly -*- C++ -*-==//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// This file is part of the WebAssembly Assembler.
11///
12/// It contains code to translate a parsed .s file into MCInsts.
13///
14//===----------------------------------------------------------------------===//
15
21#include "WebAssembly.h"
22#include "llvm/MC/MCContext.h"
23#include "llvm/MC/MCExpr.h"
24#include "llvm/MC/MCInst.h"
25#include "llvm/MC/MCInstrInfo.h"
29#include "llvm/MC/MCStreamer.h"
31#include "llvm/MC/MCSymbol.h"
35#include "llvm/Support/Endian.h"
37
38using namespace llvm;
39
40#define DEBUG_TYPE "wasm-asm-parser"
41
42extern StringRef GetMnemonic(unsigned Opc);
43
44namespace llvm {
45
47 const MCInstrInfo &MII, bool is64)
48 : Parser(Parser), MII(MII), is64(is64) {
49}
50
52 LocalTypes.assign(Sig.Params.begin(), Sig.Params.end());
53 ReturnTypes.assign(Sig.Returns.begin(), Sig.Returns.end());
54}
55
57 const SmallVectorImpl<wasm::ValType> &Locals) {
58 LocalTypes.insert(LocalTypes.end(), Locals.begin(), Locals.end());
59}
60
61void WebAssemblyAsmTypeCheck::dumpTypeStack(Twine Msg) {
63 std::string s;
64 for (auto VT : Stack) {
66 s += " ";
67 }
68 dbgs() << Msg << s << '\n';
69 });
70}
71
72bool WebAssemblyAsmTypeCheck::typeError(SMLoc ErrorLoc, const Twine &Msg) {
73 // Once you get one type error in a function, it will likely trigger more
74 // which are mostly not helpful.
75 if (TypeErrorThisFunction)
76 return true;
77 // If we're currently in unreachable code, we suppress errors completely.
78 if (Unreachable)
79 return false;
80 TypeErrorThisFunction = true;
81 dumpTypeStack("current stack: ");
82 return Parser.Error(ErrorLoc, Msg);
83}
84
85bool WebAssemblyAsmTypeCheck::popType(SMLoc ErrorLoc,
86 std::optional<wasm::ValType> EVT) {
87 if (Stack.empty()) {
88 return typeError(ErrorLoc,
89 EVT ? StringRef("empty stack while popping ") +
91 : StringRef("empty stack while popping value"));
92 }
93 auto PVT = Stack.pop_back_val();
94 if (EVT && *EVT != PVT) {
95 return typeError(ErrorLoc,
96 StringRef("popped ") + WebAssembly::typeToString(PVT) +
97 ", expected " + WebAssembly::typeToString(*EVT));
98 }
99 return false;
100}
101
102bool WebAssemblyAsmTypeCheck::popRefType(SMLoc ErrorLoc) {
103 if (Stack.empty()) {
104 return typeError(ErrorLoc, StringRef("empty stack while popping reftype"));
105 }
106 auto PVT = Stack.pop_back_val();
107 if (!WebAssembly::isRefType(PVT)) {
108 return typeError(ErrorLoc, StringRef("popped ") +
110 ", expected reftype");
111 }
112 return false;
113}
114
115bool WebAssemblyAsmTypeCheck::getLocal(SMLoc ErrorLoc, const MCInst &Inst,
117 auto Local = static_cast<size_t>(Inst.getOperand(0).getImm());
118 if (Local >= LocalTypes.size())
119 return typeError(ErrorLoc, StringRef("no local type specified for index ") +
120 std::to_string(Local));
121 Type = LocalTypes[Local];
122 return false;
123}
124
125bool WebAssemblyAsmTypeCheck::checkEnd(SMLoc ErrorLoc, bool PopVals) {
126 if (LastSig.Returns.size() > Stack.size())
127 return typeError(ErrorLoc, "end: insufficient values on the type stack");
128
129 if (PopVals) {
130 for (auto VT : llvm::reverse(LastSig.Returns)) {
131 if (popType(ErrorLoc, VT))
132 return true;
133 }
134 return false;
135 }
136
137 for (size_t i = 0; i < LastSig.Returns.size(); i++) {
138 auto EVT = LastSig.Returns[i];
139 auto PVT = Stack[Stack.size() - LastSig.Returns.size() + i];
140 if (PVT != EVT)
141 return typeError(
142 ErrorLoc, StringRef("end got ") + WebAssembly::typeToString(PVT) +
143 ", expected " + WebAssembly::typeToString(EVT));
144 }
145 return false;
146}
147
148bool WebAssemblyAsmTypeCheck::checkSig(SMLoc ErrorLoc,
149 const wasm::WasmSignature& Sig) {
150 for (auto VT : llvm::reverse(Sig.Params))
151 if (popType(ErrorLoc, VT)) return true;
152 Stack.insert(Stack.end(), Sig.Returns.begin(), Sig.Returns.end());
153 return false;
154}
155
156bool WebAssemblyAsmTypeCheck::getSymRef(SMLoc ErrorLoc, const MCInst &Inst,
157 const MCSymbolRefExpr *&SymRef) {
158 auto Op = Inst.getOperand(0);
159 if (!Op.isExpr())
160 return typeError(ErrorLoc, StringRef("expected expression operand"));
161 SymRef = dyn_cast<MCSymbolRefExpr>(Op.getExpr());
162 if (!SymRef)
163 return typeError(ErrorLoc, StringRef("expected symbol operand"));
164 return false;
165}
166
167bool WebAssemblyAsmTypeCheck::getGlobal(SMLoc ErrorLoc, const MCInst &Inst,
169 const MCSymbolRefExpr *SymRef;
170 if (getSymRef(ErrorLoc, Inst, SymRef))
171 return true;
172 auto WasmSym = cast<MCSymbolWasm>(&SymRef->getSymbol());
173 switch (WasmSym->getType().value_or(wasm::WASM_SYMBOL_TYPE_DATA)) {
175 Type = static_cast<wasm::ValType>(WasmSym->getGlobalType().Type);
176 break;
179 switch (SymRef->getKind()) {
183 return false;
184 default:
185 break;
186 }
187 [[fallthrough]];
188 default:
189 return typeError(ErrorLoc, StringRef("symbol ") + WasmSym->getName() +
190 " missing .globaltype");
191 }
192 return false;
193}
194
195bool WebAssemblyAsmTypeCheck::getTable(SMLoc ErrorLoc, const MCInst &Inst,
197 const MCSymbolRefExpr *SymRef;
198 if (getSymRef(ErrorLoc, Inst, SymRef))
199 return true;
200 auto WasmSym = cast<MCSymbolWasm>(&SymRef->getSymbol());
201 if (WasmSym->getType().value_or(wasm::WASM_SYMBOL_TYPE_DATA) !=
203 return typeError(ErrorLoc, StringRef("symbol ") + WasmSym->getName() +
204 " missing .tabletype");
205 Type = static_cast<wasm::ValType>(WasmSym->getTableType().ElemType);
206 return false;
207}
208
210 // Check the return types.
211 for (auto RVT : llvm::reverse(ReturnTypes)) {
212 if (popType(ErrorLoc, RVT))
213 return true;
214 }
215 if (!Stack.empty()) {
216 return typeError(ErrorLoc, std::to_string(Stack.size()) +
217 " superfluous return values");
218 }
219 Unreachable = true;
220 return false;
221}
222
225 auto Opc = Inst.getOpcode();
226 auto Name = GetMnemonic(Opc);
227 dumpTypeStack("typechecking " + Name + ": ");
229 if (Name == "local.get") {
230 if (getLocal(Operands[1]->getStartLoc(), Inst, Type))
231 return true;
232 Stack.push_back(Type);
233 } else if (Name == "local.set") {
234 if (getLocal(Operands[1]->getStartLoc(), Inst, Type))
235 return true;
236 if (popType(ErrorLoc, Type))
237 return true;
238 } else if (Name == "local.tee") {
239 if (getLocal(Operands[1]->getStartLoc(), Inst, Type))
240 return true;
241 if (popType(ErrorLoc, Type))
242 return true;
243 Stack.push_back(Type);
244 } else if (Name == "global.get") {
245 if (getGlobal(Operands[1]->getStartLoc(), Inst, Type))
246 return true;
247 Stack.push_back(Type);
248 } else if (Name == "global.set") {
249 if (getGlobal(Operands[1]->getStartLoc(), Inst, Type))
250 return true;
251 if (popType(ErrorLoc, Type))
252 return true;
253 } else if (Name == "table.get") {
254 if (getTable(Operands[1]->getStartLoc(), Inst, Type))
255 return true;
256 if (popType(ErrorLoc, wasm::ValType::I32))
257 return true;
258 Stack.push_back(Type);
259 } else if (Name == "table.set") {
260 if (getTable(Operands[1]->getStartLoc(), Inst, Type))
261 return true;
262 if (popType(ErrorLoc, Type))
263 return true;
264 if (popType(ErrorLoc, wasm::ValType::I32))
265 return true;
266 } else if (Name == "table.fill") {
267 if (getTable(Operands[1]->getStartLoc(), Inst, Type))
268 return true;
269 if (popType(ErrorLoc, wasm::ValType::I32))
270 return true;
271 if (popType(ErrorLoc, Type))
272 return true;
273 if (popType(ErrorLoc, wasm::ValType::I32))
274 return true;
275 } else if (Name == "drop") {
276 if (popType(ErrorLoc, {}))
277 return true;
278 } else if (Name == "end_block" || Name == "end_loop" || Name == "end_if" ||
279 Name == "else" || Name == "end_try") {
280 if (checkEnd(ErrorLoc, Name == "else"))
281 return true;
282 if (Name == "end_block")
283 Unreachable = false;
284 } else if (Name == "return") {
285 if (endOfFunction(ErrorLoc))
286 return true;
287 } else if (Name == "call_indirect" || Name == "return_call_indirect") {
288 // Function value.
289 if (popType(ErrorLoc, wasm::ValType::I32)) return true;
290 if (checkSig(ErrorLoc, LastSig)) return true;
291 if (Name == "return_call_indirect" && endOfFunction(ErrorLoc))
292 return true;
293 } else if (Name == "call" || Name == "return_call") {
294 const MCSymbolRefExpr *SymRef;
295 if (getSymRef(Operands[1]->getStartLoc(), Inst, SymRef))
296 return true;
297 auto WasmSym = cast<MCSymbolWasm>(&SymRef->getSymbol());
298 auto Sig = WasmSym->getSignature();
299 if (!Sig || WasmSym->getType() != wasm::WASM_SYMBOL_TYPE_FUNCTION)
300 return typeError(Operands[1]->getStartLoc(), StringRef("symbol ") +
301 WasmSym->getName() +
302 " missing .functype");
303 if (checkSig(ErrorLoc, *Sig)) return true;
304 if (Name == "return_call" && endOfFunction(ErrorLoc))
305 return true;
306 } else if (Name == "catch") {
307 const MCSymbolRefExpr *SymRef;
308 if (getSymRef(Operands[1]->getStartLoc(), Inst, SymRef))
309 return true;
310 const auto *WasmSym = cast<MCSymbolWasm>(&SymRef->getSymbol());
311 const auto *Sig = WasmSym->getSignature();
312 if (!Sig || WasmSym->getType() != wasm::WASM_SYMBOL_TYPE_TAG)
313 return typeError(Operands[1]->getStartLoc(), StringRef("symbol ") +
314 WasmSym->getName() +
315 " missing .tagtype");
316 // catch instruction pushes values whose types are specified in the tag's
317 // "params" part
318 Stack.insert(Stack.end(), Sig->Params.begin(), Sig->Params.end());
319 } else if (Name == "unreachable") {
320 Unreachable = true;
321 } else if (Name == "ref.is_null") {
322 if (popRefType(ErrorLoc))
323 return true;
325 } else {
326 // The current instruction is a stack instruction which doesn't have
327 // explicit operands that indicate push/pop types, so we get those from
328 // the register version of the same instruction.
329 auto RegOpc = WebAssembly::getRegisterOpcode(Opc);
330 assert(RegOpc != -1 && "Failed to get register version of MC instruction");
331 const auto &II = MII.get(RegOpc);
332 // First pop all the uses off the stack and check them.
333 for (unsigned I = II.getNumOperands(); I > II.getNumDefs(); I--) {
334 const auto &Op = II.operands()[I - 1];
335 if (Op.OperandType == MCOI::OPERAND_REGISTER) {
336 auto VT = WebAssembly::regClassToValType(Op.RegClass);
337 if (popType(ErrorLoc, VT))
338 return true;
339 }
340 }
341 // Now push all the defs onto the stack.
342 for (unsigned I = 0; I < II.getNumDefs(); I++) {
343 const auto &Op = II.operands()[I];
344 assert(Op.OperandType == MCOI::OPERAND_REGISTER && "Register expected");
345 auto VT = WebAssembly::regClassToValType(Op.RegClass);
346 Stack.push_back(VT);
347 }
348 }
349 return false;
350}
351
352} // end namespace llvm
#define LLVM_DEBUG(X)
Definition: Debug.h:101
std::string Name
#define I(x, y, z)
Definition: MD5.cpp:58
mir Rename Register Operands
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
StringRef GetMnemonic(unsigned Opc)
StringRef GetMnemonic(unsigned Opc)
This file is part of the WebAssembly Assembler.
This file provides WebAssembly-specific target descriptions.
This file contains the declaration of the WebAssembly-specific type parsing utility functions.
This file registers the WebAssembly target.
This file declares WebAssembly-specific target streamer classes.
This file contains the entry points for global functions defined in the LLVM WebAssembly back-end.
Generic assembler parser interface, for use by target specific assembly parsers.
Definition: MCAsmParser.h:123
bool Error(SMLoc L, const Twine &Msg, SMRange Range=std::nullopt)
Return an error at the location L, with the message Msg.
Instances of this class represent a single low-level machine instruction.
Definition: MCInst.h:184
unsigned getOpcode() const
Definition: MCInst.h:198
const MCOperand & getOperand(unsigned i) const
Definition: MCInst.h:206
Interface to description of machine instruction set.
Definition: MCInstrInfo.h:26
const MCInstrDesc & get(unsigned Opcode) const
Return the machine instruction descriptor that corresponds to the specified instruction opcode.
Definition: MCInstrInfo.h:63
int64_t getImm() const
Definition: MCInst.h:80
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:192
const MCSymbol & getSymbol() const
Definition: MCExpr.h:399
VariantKind getKind() const
Definition: MCExpr.h:401
Represents a location in source code.
Definition: SMLoc.h:23
bool empty() const
Definition: SmallVector.h:94
size_t size() const
Definition: SmallVector.h:91
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: SmallVector.h:577
void assign(size_type NumElts, ValueParamT Elt)
Definition: SmallVector.h:708
iterator insert(iterator I, T &&Elt)
Definition: SmallVector.h:809
void push_back(const T &Elt)
Definition: SmallVector.h:416
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
The instances of the Type class are immutable: once they are created, they are never changed.
Definition: Type.h:45
void funcDecl(const wasm::WasmSignature &Sig)
void localDecl(const SmallVectorImpl< wasm::ValType > &Locals)
WebAssemblyAsmTypeCheck(MCAsmParser &Parser, const MCInstrInfo &MII, bool is64)
bool typeCheck(SMLoc ErrorLoc, const MCInst &Inst, OperandVector &Operands)
@ OPERAND_REGISTER
Definition: MCInstrDesc.h:61
const char * typeToString(wasm::ValType Type)
wasm::ValType regClassToValType(unsigned RC)
bool isRefType(wasm::ValType Type)
int getRegisterOpcode(unsigned short Opcode)
@ WASM_SYMBOL_TYPE_GLOBAL
Definition: Wasm.h:385
@ WASM_SYMBOL_TYPE_DATA
Definition: Wasm.h:384
@ WASM_SYMBOL_TYPE_TAG
Definition: Wasm.h:387
@ WASM_SYMBOL_TYPE_TABLE
Definition: Wasm.h:388
@ WASM_SYMBOL_TYPE_FUNCTION
Definition: Wasm.h:383
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
auto reverse(ContainerTy &&C)
Definition: STLExtras.h:511
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163
Extended Value Type.
Definition: ValueTypes.h:34
SmallVector< ValType, 1 > Returns
Definition: Wasm.h:435
SmallVector< ValType, 4 > Params
Definition: Wasm.h:436