xref: /freebsd-src/contrib/llvm-project/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp (revision 1db9f3b21e39176dd5b67cf8ac378633b172463e)
1 //===--- RuntimeDyldChecker.cpp - RuntimeDyld tester framework --*- 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 #include "llvm/ExecutionEngine/RuntimeDyldChecker.h"
10 #include "RuntimeDyldCheckerImpl.h"
11 #include "llvm/ADT/STLExtras.h"
12 #include "llvm/ADT/StringExtras.h"
13 #include "llvm/MC/MCAsmInfo.h"
14 #include "llvm/MC/MCContext.h"
15 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
16 #include "llvm/MC/MCInst.h"
17 #include "llvm/MC/MCInstPrinter.h"
18 #include "llvm/MC/MCInstrInfo.h"
19 #include "llvm/MC/MCRegisterInfo.h"
20 #include "llvm/MC/MCSubtargetInfo.h"
21 #include "llvm/MC/MCTargetOptions.h"
22 #include "llvm/MC/TargetRegistry.h"
23 #include "llvm/Support/Endian.h"
24 #include "llvm/Support/MSVCErrorWorkarounds.h"
25 #include "llvm/Support/MemoryBuffer.h"
26 #include "llvm/Support/Path.h"
27 #include <cctype>
28 #include <memory>
29 #include <utility>
30 
31 #define DEBUG_TYPE "rtdyld"
32 
33 using namespace llvm;
34 
35 namespace {
36 struct TargetInfo {
37   const Target *TheTarget;
38   std::unique_ptr<MCSubtargetInfo> STI;
39   std::unique_ptr<MCRegisterInfo> MRI;
40   std::unique_ptr<MCAsmInfo> MAI;
41   std::unique_ptr<MCContext> Ctx;
42   std::unique_ptr<MCDisassembler> Disassembler;
43   std::unique_ptr<MCInstrInfo> MII;
44   std::unique_ptr<MCInstPrinter> InstPrinter;
45 };
46 } // anonymous namespace
47 
48 namespace llvm {
49 
50 // Helper class that implements the language evaluated by RuntimeDyldChecker.
51 class RuntimeDyldCheckerExprEval {
52 public:
53   RuntimeDyldCheckerExprEval(const RuntimeDyldCheckerImpl &Checker,
54                              raw_ostream &ErrStream)
55       : Checker(Checker) {}
56 
57   bool evaluate(StringRef Expr) const {
58     // Expect equality expression of the form 'LHS = RHS'.
59     Expr = Expr.trim();
60     size_t EQIdx = Expr.find('=');
61 
62     ParseContext OutsideLoad(false);
63 
64     // Evaluate LHS.
65     StringRef LHSExpr = Expr.substr(0, EQIdx).rtrim();
66     StringRef RemainingExpr;
67     EvalResult LHSResult;
68     std::tie(LHSResult, RemainingExpr) =
69         evalComplexExpr(evalSimpleExpr(LHSExpr, OutsideLoad), OutsideLoad);
70     if (LHSResult.hasError())
71       return handleError(Expr, LHSResult);
72     if (RemainingExpr != "")
73       return handleError(Expr, unexpectedToken(RemainingExpr, LHSExpr, ""));
74 
75     // Evaluate RHS.
76     StringRef RHSExpr = Expr.substr(EQIdx + 1).ltrim();
77     EvalResult RHSResult;
78     std::tie(RHSResult, RemainingExpr) =
79         evalComplexExpr(evalSimpleExpr(RHSExpr, OutsideLoad), OutsideLoad);
80     if (RHSResult.hasError())
81       return handleError(Expr, RHSResult);
82     if (RemainingExpr != "")
83       return handleError(Expr, unexpectedToken(RemainingExpr, RHSExpr, ""));
84 
85     if (LHSResult.getValue() != RHSResult.getValue()) {
86       Checker.ErrStream << "Expression '" << Expr << "' is false: "
87                         << format("0x%" PRIx64, LHSResult.getValue())
88                         << " != " << format("0x%" PRIx64, RHSResult.getValue())
89                         << "\n";
90       return false;
91     }
92     return true;
93   }
94 
95 private:
96   // RuntimeDyldCheckerExprEval requires some context when parsing exprs. In
97   // particular, it needs to know whether a symbol is being evaluated in the
98   // context of a load, in which case we want the linker's local address for
99   // the symbol, or outside of a load, in which case we want the symbol's
100   // address in the remote target.
101 
102   struct ParseContext {
103     bool IsInsideLoad;
104     ParseContext(bool IsInsideLoad) : IsInsideLoad(IsInsideLoad) {}
105   };
106 
107   const RuntimeDyldCheckerImpl &Checker;
108 
109   enum class BinOpToken : unsigned {
110     Invalid,
111     Add,
112     Sub,
113     BitwiseAnd,
114     BitwiseOr,
115     ShiftLeft,
116     ShiftRight
117   };
118 
119   class EvalResult {
120   public:
121     EvalResult() : Value(0) {}
122     EvalResult(uint64_t Value) : Value(Value) {}
123     EvalResult(std::string ErrorMsg)
124         : Value(0), ErrorMsg(std::move(ErrorMsg)) {}
125     uint64_t getValue() const { return Value; }
126     bool hasError() const { return ErrorMsg != ""; }
127     const std::string &getErrorMsg() const { return ErrorMsg; }
128 
129   private:
130     uint64_t Value;
131     std::string ErrorMsg;
132   };
133 
134   StringRef getTokenForError(StringRef Expr) const {
135     if (Expr.empty())
136       return "";
137 
138     StringRef Token, Remaining;
139     if (isalpha(Expr[0]))
140       std::tie(Token, Remaining) = parseSymbol(Expr);
141     else if (isdigit(Expr[0]))
142       std::tie(Token, Remaining) = parseNumberString(Expr);
143     else {
144       unsigned TokLen = 1;
145       if (Expr.starts_with("<<") || Expr.starts_with(">>"))
146         TokLen = 2;
147       Token = Expr.substr(0, TokLen);
148     }
149     return Token;
150   }
151 
152   EvalResult unexpectedToken(StringRef TokenStart, StringRef SubExpr,
153                              StringRef ErrText) const {
154     std::string ErrorMsg("Encountered unexpected token '");
155     ErrorMsg += getTokenForError(TokenStart);
156     if (SubExpr != "") {
157       ErrorMsg += "' while parsing subexpression '";
158       ErrorMsg += SubExpr;
159     }
160     ErrorMsg += "'";
161     if (ErrText != "") {
162       ErrorMsg += " ";
163       ErrorMsg += ErrText;
164     }
165     return EvalResult(std::move(ErrorMsg));
166   }
167 
168   bool handleError(StringRef Expr, const EvalResult &R) const {
169     assert(R.hasError() && "Not an error result.");
170     Checker.ErrStream << "Error evaluating expression '" << Expr
171                       << "': " << R.getErrorMsg() << "\n";
172     return false;
173   }
174 
175   std::pair<BinOpToken, StringRef> parseBinOpToken(StringRef Expr) const {
176     if (Expr.empty())
177       return std::make_pair(BinOpToken::Invalid, "");
178 
179     // Handle the two 2-character tokens.
180     if (Expr.starts_with("<<"))
181       return std::make_pair(BinOpToken::ShiftLeft, Expr.substr(2).ltrim());
182     if (Expr.starts_with(">>"))
183       return std::make_pair(BinOpToken::ShiftRight, Expr.substr(2).ltrim());
184 
185     // Handle one-character tokens.
186     BinOpToken Op;
187     switch (Expr[0]) {
188     default:
189       return std::make_pair(BinOpToken::Invalid, Expr);
190     case '+':
191       Op = BinOpToken::Add;
192       break;
193     case '-':
194       Op = BinOpToken::Sub;
195       break;
196     case '&':
197       Op = BinOpToken::BitwiseAnd;
198       break;
199     case '|':
200       Op = BinOpToken::BitwiseOr;
201       break;
202     }
203 
204     return std::make_pair(Op, Expr.substr(1).ltrim());
205   }
206 
207   EvalResult computeBinOpResult(BinOpToken Op, const EvalResult &LHSResult,
208                                 const EvalResult &RHSResult) const {
209     switch (Op) {
210     default:
211       llvm_unreachable("Tried to evaluate unrecognized operation.");
212     case BinOpToken::Add:
213       return EvalResult(LHSResult.getValue() + RHSResult.getValue());
214     case BinOpToken::Sub:
215       return EvalResult(LHSResult.getValue() - RHSResult.getValue());
216     case BinOpToken::BitwiseAnd:
217       return EvalResult(LHSResult.getValue() & RHSResult.getValue());
218     case BinOpToken::BitwiseOr:
219       return EvalResult(LHSResult.getValue() | RHSResult.getValue());
220     case BinOpToken::ShiftLeft:
221       return EvalResult(LHSResult.getValue() << RHSResult.getValue());
222     case BinOpToken::ShiftRight:
223       return EvalResult(LHSResult.getValue() >> RHSResult.getValue());
224     }
225   }
226 
227   // Parse a symbol and return a (string, string) pair representing the symbol
228   // name and expression remaining to be parsed.
229   std::pair<StringRef, StringRef> parseSymbol(StringRef Expr) const {
230     size_t FirstNonSymbol = Expr.find_first_not_of("0123456789"
231                                                    "abcdefghijklmnopqrstuvwxyz"
232                                                    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
233                                                    ":_.$");
234     return std::make_pair(Expr.substr(0, FirstNonSymbol),
235                           Expr.substr(FirstNonSymbol).ltrim());
236   }
237 
238   // Evaluate a call to decode_operand. Decode the instruction operand at the
239   // given symbol and get the value of the requested operand.
240   // Returns an error if the instruction cannot be decoded, or the requested
241   // operand is not an immediate.
242   // On success, returns a pair containing the value of the operand, plus
243   // the expression remaining to be evaluated.
244   std::pair<EvalResult, StringRef> evalDecodeOperand(StringRef Expr) const {
245     if (!Expr.starts_with("("))
246       return std::make_pair(unexpectedToken(Expr, Expr, "expected '('"), "");
247     StringRef RemainingExpr = Expr.substr(1).ltrim();
248     StringRef Symbol;
249     std::tie(Symbol, RemainingExpr) = parseSymbol(RemainingExpr);
250 
251     if (!Checker.isSymbolValid(Symbol))
252       return std::make_pair(
253           EvalResult(("Cannot decode unknown symbol '" + Symbol + "'").str()),
254           "");
255 
256     // if there is an offset number expr
257     int64_t Offset = 0;
258     BinOpToken BinOp;
259     std::tie(BinOp, RemainingExpr) = parseBinOpToken(RemainingExpr);
260     switch (BinOp) {
261     case BinOpToken::Add: {
262       EvalResult Number;
263       std::tie(Number, RemainingExpr) = evalNumberExpr(RemainingExpr);
264       Offset = Number.getValue();
265       break;
266     }
267     case BinOpToken::Invalid:
268       break;
269     default:
270       return std::make_pair(
271           unexpectedToken(RemainingExpr, RemainingExpr,
272                           "expected '+' for offset or ',' if no offset"),
273           "");
274     }
275 
276     if (!RemainingExpr.starts_with(","))
277       return std::make_pair(
278           unexpectedToken(RemainingExpr, RemainingExpr, "expected ','"), "");
279     RemainingExpr = RemainingExpr.substr(1).ltrim();
280 
281     EvalResult OpIdxExpr;
282     std::tie(OpIdxExpr, RemainingExpr) = evalNumberExpr(RemainingExpr);
283     if (OpIdxExpr.hasError())
284       return std::make_pair(OpIdxExpr, "");
285 
286     if (!RemainingExpr.starts_with(")"))
287       return std::make_pair(
288           unexpectedToken(RemainingExpr, RemainingExpr, "expected ')'"), "");
289     RemainingExpr = RemainingExpr.substr(1).ltrim();
290 
291     MCInst Inst;
292     uint64_t Size;
293     if (!decodeInst(Symbol, Inst, Size, Offset))
294       return std::make_pair(
295           EvalResult(("Couldn't decode instruction at '" + Symbol + "'").str()),
296           "");
297 
298     unsigned OpIdx = OpIdxExpr.getValue();
299 
300     auto printInst = [this](StringRef Symbol, MCInst Inst,
301                             raw_string_ostream &ErrMsgStream) {
302       auto TT = Checker.getTripleForSymbol(Checker.getTargetFlag(Symbol));
303       auto TI = getTargetInfo(TT, Checker.getCPU(), Checker.getFeatures());
304       if (auto E = TI.takeError()) {
305         errs() << "Error obtaining instruction printer: "
306                << toString(std::move(E)) << "\n";
307         return std::make_pair(EvalResult(ErrMsgStream.str()), "");
308       }
309       Inst.dump_pretty(ErrMsgStream, TI->InstPrinter.get());
310       return std::make_pair(EvalResult(ErrMsgStream.str()), "");
311     };
312 
313     if (OpIdx >= Inst.getNumOperands()) {
314       std::string ErrMsg;
315       raw_string_ostream ErrMsgStream(ErrMsg);
316       ErrMsgStream << "Invalid operand index '" << format("%i", OpIdx)
317                    << "' for instruction '" << Symbol
318                    << "'. Instruction has only "
319                    << format("%i", Inst.getNumOperands())
320                    << " operands.\nInstruction is:\n  ";
321 
322       return printInst(Symbol, Inst, ErrMsgStream);
323     }
324 
325     const MCOperand &Op = Inst.getOperand(OpIdx);
326     if (!Op.isImm()) {
327       std::string ErrMsg;
328       raw_string_ostream ErrMsgStream(ErrMsg);
329       ErrMsgStream << "Operand '" << format("%i", OpIdx) << "' of instruction '"
330                    << Symbol << "' is not an immediate.\nInstruction is:\n  ";
331 
332       return printInst(Symbol, Inst, ErrMsgStream);
333     }
334 
335     return std::make_pair(EvalResult(Op.getImm()), RemainingExpr);
336   }
337 
338   // Evaluate a call to next_pc.
339   // Decode the instruction at the given symbol and return the following program
340   // counter.
341   // Returns an error if the instruction cannot be decoded.
342   // On success, returns a pair containing the next PC, plus of the
343   // expression remaining to be evaluated.
344   std::pair<EvalResult, StringRef> evalNextPC(StringRef Expr,
345                                               ParseContext PCtx) const {
346     if (!Expr.starts_with("("))
347       return std::make_pair(unexpectedToken(Expr, Expr, "expected '('"), "");
348     StringRef RemainingExpr = Expr.substr(1).ltrim();
349     StringRef Symbol;
350     std::tie(Symbol, RemainingExpr) = parseSymbol(RemainingExpr);
351 
352     if (!Checker.isSymbolValid(Symbol))
353       return std::make_pair(
354           EvalResult(("Cannot decode unknown symbol '" + Symbol + "'").str()),
355           "");
356 
357     if (!RemainingExpr.starts_with(")"))
358       return std::make_pair(
359           unexpectedToken(RemainingExpr, RemainingExpr, "expected ')'"), "");
360     RemainingExpr = RemainingExpr.substr(1).ltrim();
361 
362     MCInst Inst;
363     uint64_t InstSize;
364     if (!decodeInst(Symbol, Inst, InstSize, 0))
365       return std::make_pair(
366           EvalResult(("Couldn't decode instruction at '" + Symbol + "'").str()),
367           "");
368 
369     uint64_t SymbolAddr = PCtx.IsInsideLoad
370                               ? Checker.getSymbolLocalAddr(Symbol)
371                               : Checker.getSymbolRemoteAddr(Symbol);
372     uint64_t NextPC = SymbolAddr + InstSize;
373 
374     return std::make_pair(EvalResult(NextPC), RemainingExpr);
375   }
376 
377   // Evaluate a call to stub_addr/got_addr.
378   // Look up and return the address of the stub for the given
379   // (<file name>, <section name>, <symbol name>) tuple.
380   // On success, returns a pair containing the stub address, plus the expression
381   // remaining to be evaluated.
382   std::pair<EvalResult, StringRef>
383   evalStubOrGOTAddr(StringRef Expr, ParseContext PCtx, bool IsStubAddr) const {
384     if (!Expr.starts_with("("))
385       return std::make_pair(unexpectedToken(Expr, Expr, "expected '('"), "");
386     StringRef RemainingExpr = Expr.substr(1).ltrim();
387 
388     // Handle file-name specially, as it may contain characters that aren't
389     // legal for symbols.
390     StringRef StubContainerName;
391     size_t ComaIdx = RemainingExpr.find(',');
392     StubContainerName = RemainingExpr.substr(0, ComaIdx).rtrim();
393     RemainingExpr = RemainingExpr.substr(ComaIdx).ltrim();
394 
395     if (!RemainingExpr.starts_with(","))
396       return std::make_pair(
397           unexpectedToken(RemainingExpr, Expr, "expected ','"), "");
398     RemainingExpr = RemainingExpr.substr(1).ltrim();
399 
400     StringRef Symbol;
401     std::tie(Symbol, RemainingExpr) = parseSymbol(RemainingExpr);
402 
403     if (!RemainingExpr.starts_with(")"))
404       return std::make_pair(
405           unexpectedToken(RemainingExpr, Expr, "expected ')'"), "");
406     RemainingExpr = RemainingExpr.substr(1).ltrim();
407 
408     uint64_t StubAddr;
409     std::string ErrorMsg;
410     std::tie(StubAddr, ErrorMsg) = Checker.getStubOrGOTAddrFor(
411         StubContainerName, Symbol, PCtx.IsInsideLoad, IsStubAddr);
412 
413     if (ErrorMsg != "")
414       return std::make_pair(EvalResult(ErrorMsg), "");
415 
416     return std::make_pair(EvalResult(StubAddr), RemainingExpr);
417   }
418 
419   std::pair<EvalResult, StringRef> evalSectionAddr(StringRef Expr,
420                                                    ParseContext PCtx) const {
421     if (!Expr.starts_with("("))
422       return std::make_pair(unexpectedToken(Expr, Expr, "expected '('"), "");
423     StringRef RemainingExpr = Expr.substr(1).ltrim();
424 
425     // Handle file-name specially, as it may contain characters that aren't
426     // legal for symbols.
427     StringRef FileName;
428     size_t ComaIdx = RemainingExpr.find(',');
429     FileName = RemainingExpr.substr(0, ComaIdx).rtrim();
430     RemainingExpr = RemainingExpr.substr(ComaIdx).ltrim();
431 
432     if (!RemainingExpr.starts_with(","))
433       return std::make_pair(
434           unexpectedToken(RemainingExpr, Expr, "expected ','"), "");
435     RemainingExpr = RemainingExpr.substr(1).ltrim();
436 
437     StringRef SectionName;
438     size_t CloseParensIdx = RemainingExpr.find(')');
439     SectionName = RemainingExpr.substr(0, CloseParensIdx).rtrim();
440     RemainingExpr = RemainingExpr.substr(CloseParensIdx).ltrim();
441 
442     if (!RemainingExpr.starts_with(")"))
443       return std::make_pair(
444           unexpectedToken(RemainingExpr, Expr, "expected ')'"), "");
445     RemainingExpr = RemainingExpr.substr(1).ltrim();
446 
447     uint64_t StubAddr;
448     std::string ErrorMsg;
449     std::tie(StubAddr, ErrorMsg) = Checker.getSectionAddr(
450         FileName, SectionName, PCtx.IsInsideLoad);
451 
452     if (ErrorMsg != "")
453       return std::make_pair(EvalResult(ErrorMsg), "");
454 
455     return std::make_pair(EvalResult(StubAddr), RemainingExpr);
456   }
457 
458   // Evaluate an identifier expr, which may be a symbol, or a call to
459   // one of the builtin functions: get_insn_opcode or get_insn_length.
460   // Return the result, plus the expression remaining to be parsed.
461   std::pair<EvalResult, StringRef> evalIdentifierExpr(StringRef Expr,
462                                                       ParseContext PCtx) const {
463     StringRef Symbol;
464     StringRef RemainingExpr;
465     std::tie(Symbol, RemainingExpr) = parseSymbol(Expr);
466 
467     // Check for builtin function calls.
468     if (Symbol == "decode_operand")
469       return evalDecodeOperand(RemainingExpr);
470     else if (Symbol == "next_pc")
471       return evalNextPC(RemainingExpr, PCtx);
472     else if (Symbol == "stub_addr")
473       return evalStubOrGOTAddr(RemainingExpr, PCtx, true);
474     else if (Symbol == "got_addr")
475       return evalStubOrGOTAddr(RemainingExpr, PCtx, false);
476     else if (Symbol == "section_addr")
477       return evalSectionAddr(RemainingExpr, PCtx);
478 
479     if (!Checker.isSymbolValid(Symbol)) {
480       std::string ErrMsg("No known address for symbol '");
481       ErrMsg += Symbol;
482       ErrMsg += "'";
483       if (Symbol.starts_with("L"))
484         ErrMsg += " (this appears to be an assembler local label - "
485                   " perhaps drop the 'L'?)";
486 
487       return std::make_pair(EvalResult(ErrMsg), "");
488     }
489 
490     // The value for the symbol depends on the context we're evaluating in:
491     // Inside a load this is the address in the linker's memory, outside a
492     // load it's the address in the target processes memory.
493     uint64_t Value = PCtx.IsInsideLoad ? Checker.getSymbolLocalAddr(Symbol)
494                                        : Checker.getSymbolRemoteAddr(Symbol);
495 
496     // Looks like a plain symbol reference.
497     return std::make_pair(EvalResult(Value), RemainingExpr);
498   }
499 
500   // Parse a number (hexadecimal or decimal) and return a (string, string)
501   // pair representing the number and the expression remaining to be parsed.
502   std::pair<StringRef, StringRef> parseNumberString(StringRef Expr) const {
503     size_t FirstNonDigit = StringRef::npos;
504     if (Expr.starts_with("0x")) {
505       FirstNonDigit = Expr.find_first_not_of("0123456789abcdefABCDEF", 2);
506       if (FirstNonDigit == StringRef::npos)
507         FirstNonDigit = Expr.size();
508     } else {
509       FirstNonDigit = Expr.find_first_not_of("0123456789");
510       if (FirstNonDigit == StringRef::npos)
511         FirstNonDigit = Expr.size();
512     }
513     return std::make_pair(Expr.substr(0, FirstNonDigit),
514                           Expr.substr(FirstNonDigit));
515   }
516 
517   // Evaluate a constant numeric expression (hexadecimal or decimal) and
518   // return a pair containing the result, and the expression remaining to be
519   // evaluated.
520   std::pair<EvalResult, StringRef> evalNumberExpr(StringRef Expr) const {
521     StringRef ValueStr;
522     StringRef RemainingExpr;
523     std::tie(ValueStr, RemainingExpr) = parseNumberString(Expr);
524 
525     if (ValueStr.empty() || !isdigit(ValueStr[0]))
526       return std::make_pair(
527           unexpectedToken(RemainingExpr, RemainingExpr, "expected number"), "");
528     uint64_t Value;
529     ValueStr.getAsInteger(0, Value);
530     return std::make_pair(EvalResult(Value), RemainingExpr);
531   }
532 
533   // Evaluate an expression of the form "(<expr>)" and return a pair
534   // containing the result of evaluating <expr>, plus the expression
535   // remaining to be parsed.
536   std::pair<EvalResult, StringRef> evalParensExpr(StringRef Expr,
537                                                   ParseContext PCtx) const {
538     assert(Expr.starts_with("(") && "Not a parenthesized expression");
539     EvalResult SubExprResult;
540     StringRef RemainingExpr;
541     std::tie(SubExprResult, RemainingExpr) =
542         evalComplexExpr(evalSimpleExpr(Expr.substr(1).ltrim(), PCtx), PCtx);
543     if (SubExprResult.hasError())
544       return std::make_pair(SubExprResult, "");
545     if (!RemainingExpr.starts_with(")"))
546       return std::make_pair(
547           unexpectedToken(RemainingExpr, Expr, "expected ')'"), "");
548     RemainingExpr = RemainingExpr.substr(1).ltrim();
549     return std::make_pair(SubExprResult, RemainingExpr);
550   }
551 
552   // Evaluate an expression in one of the following forms:
553   //   *{<number>}<expr>
554   // Return a pair containing the result, plus the expression remaining to be
555   // parsed.
556   std::pair<EvalResult, StringRef> evalLoadExpr(StringRef Expr) const {
557     assert(Expr.starts_with("*") && "Not a load expression");
558     StringRef RemainingExpr = Expr.substr(1).ltrim();
559 
560     // Parse read size.
561     if (!RemainingExpr.starts_with("{"))
562       return std::make_pair(EvalResult("Expected '{' following '*'."), "");
563     RemainingExpr = RemainingExpr.substr(1).ltrim();
564     EvalResult ReadSizeExpr;
565     std::tie(ReadSizeExpr, RemainingExpr) = evalNumberExpr(RemainingExpr);
566     if (ReadSizeExpr.hasError())
567       return std::make_pair(ReadSizeExpr, RemainingExpr);
568     uint64_t ReadSize = ReadSizeExpr.getValue();
569     if (ReadSize < 1 || ReadSize > 8)
570       return std::make_pair(EvalResult("Invalid size for dereference."), "");
571     if (!RemainingExpr.starts_with("}"))
572       return std::make_pair(EvalResult("Missing '}' for dereference."), "");
573     RemainingExpr = RemainingExpr.substr(1).ltrim();
574 
575     // Evaluate the expression representing the load address.
576     ParseContext LoadCtx(true);
577     EvalResult LoadAddrExprResult;
578     std::tie(LoadAddrExprResult, RemainingExpr) =
579         evalComplexExpr(evalSimpleExpr(RemainingExpr, LoadCtx), LoadCtx);
580 
581     if (LoadAddrExprResult.hasError())
582       return std::make_pair(LoadAddrExprResult, "");
583 
584     uint64_t LoadAddr = LoadAddrExprResult.getValue();
585 
586     // If there is no error but the content pointer is null then this is a
587     // zero-fill symbol/section.
588     if (LoadAddr == 0)
589       return std::make_pair(0, RemainingExpr);
590 
591     return std::make_pair(
592         EvalResult(Checker.readMemoryAtAddr(LoadAddr, ReadSize)),
593         RemainingExpr);
594   }
595 
596   // Evaluate a "simple" expression. This is any expression that _isn't_ an
597   // un-parenthesized binary expression.
598   //
599   // "Simple" expressions can be optionally bit-sliced. See evalSlicedExpr.
600   //
601   // Returns a pair containing the result of the evaluation, plus the
602   // expression remaining to be parsed.
603   std::pair<EvalResult, StringRef> evalSimpleExpr(StringRef Expr,
604                                                   ParseContext PCtx) const {
605     EvalResult SubExprResult;
606     StringRef RemainingExpr;
607 
608     if (Expr.empty())
609       return std::make_pair(EvalResult("Unexpected end of expression"), "");
610 
611     if (Expr[0] == '(')
612       std::tie(SubExprResult, RemainingExpr) = evalParensExpr(Expr, PCtx);
613     else if (Expr[0] == '*')
614       std::tie(SubExprResult, RemainingExpr) = evalLoadExpr(Expr);
615     else if (isalpha(Expr[0]) || Expr[0] == '_')
616       std::tie(SubExprResult, RemainingExpr) = evalIdentifierExpr(Expr, PCtx);
617     else if (isdigit(Expr[0]))
618       std::tie(SubExprResult, RemainingExpr) = evalNumberExpr(Expr);
619     else
620       return std::make_pair(
621           unexpectedToken(Expr, Expr,
622                           "expected '(', '*', identifier, or number"), "");
623 
624     if (SubExprResult.hasError())
625       return std::make_pair(SubExprResult, RemainingExpr);
626 
627     // Evaluate bit-slice if present.
628     if (RemainingExpr.starts_with("["))
629       std::tie(SubExprResult, RemainingExpr) =
630           evalSliceExpr(std::make_pair(SubExprResult, RemainingExpr));
631 
632     return std::make_pair(SubExprResult, RemainingExpr);
633   }
634 
635   // Evaluate a bit-slice of an expression.
636   // A bit-slice has the form "<expr>[high:low]". The result of evaluating a
637   // slice is the bits between high and low (inclusive) in the original
638   // expression, right shifted so that the "low" bit is in position 0 in the
639   // result.
640   // Returns a pair containing the result of the slice operation, plus the
641   // expression remaining to be parsed.
642   std::pair<EvalResult, StringRef>
643   evalSliceExpr(const std::pair<EvalResult, StringRef> &Ctx) const {
644     EvalResult SubExprResult;
645     StringRef RemainingExpr;
646     std::tie(SubExprResult, RemainingExpr) = Ctx;
647 
648     assert(RemainingExpr.starts_with("[") && "Not a slice expr.");
649     RemainingExpr = RemainingExpr.substr(1).ltrim();
650 
651     EvalResult HighBitExpr;
652     std::tie(HighBitExpr, RemainingExpr) = evalNumberExpr(RemainingExpr);
653 
654     if (HighBitExpr.hasError())
655       return std::make_pair(HighBitExpr, RemainingExpr);
656 
657     if (!RemainingExpr.starts_with(":"))
658       return std::make_pair(
659           unexpectedToken(RemainingExpr, RemainingExpr, "expected ':'"), "");
660     RemainingExpr = RemainingExpr.substr(1).ltrim();
661 
662     EvalResult LowBitExpr;
663     std::tie(LowBitExpr, RemainingExpr) = evalNumberExpr(RemainingExpr);
664 
665     if (LowBitExpr.hasError())
666       return std::make_pair(LowBitExpr, RemainingExpr);
667 
668     if (!RemainingExpr.starts_with("]"))
669       return std::make_pair(
670           unexpectedToken(RemainingExpr, RemainingExpr, "expected ']'"), "");
671     RemainingExpr = RemainingExpr.substr(1).ltrim();
672 
673     unsigned HighBit = HighBitExpr.getValue();
674     unsigned LowBit = LowBitExpr.getValue();
675     uint64_t Mask = ((uint64_t)1 << (HighBit - LowBit + 1)) - 1;
676     uint64_t SlicedValue = (SubExprResult.getValue() >> LowBit) & Mask;
677     return std::make_pair(EvalResult(SlicedValue), RemainingExpr);
678   }
679 
680   // Evaluate a "complex" expression.
681   // Takes an already evaluated subexpression and checks for the presence of a
682   // binary operator, computing the result of the binary operation if one is
683   // found. Used to make arithmetic expressions left-associative.
684   // Returns a pair containing the ultimate result of evaluating the
685   // expression, plus the expression remaining to be evaluated.
686   std::pair<EvalResult, StringRef>
687   evalComplexExpr(const std::pair<EvalResult, StringRef> &LHSAndRemaining,
688                   ParseContext PCtx) const {
689     EvalResult LHSResult;
690     StringRef RemainingExpr;
691     std::tie(LHSResult, RemainingExpr) = LHSAndRemaining;
692 
693     // If there was an error, or there's nothing left to evaluate, return the
694     // result.
695     if (LHSResult.hasError() || RemainingExpr == "")
696       return std::make_pair(LHSResult, RemainingExpr);
697 
698     // Otherwise check if this is a binary expression.
699     BinOpToken BinOp;
700     std::tie(BinOp, RemainingExpr) = parseBinOpToken(RemainingExpr);
701 
702     // If this isn't a recognized expression just return.
703     if (BinOp == BinOpToken::Invalid)
704       return std::make_pair(LHSResult, RemainingExpr);
705 
706     // This is a recognized bin-op. Evaluate the RHS, then evaluate the binop.
707     EvalResult RHSResult;
708     std::tie(RHSResult, RemainingExpr) = evalSimpleExpr(RemainingExpr, PCtx);
709 
710     // If there was an error evaluating the RHS, return it.
711     if (RHSResult.hasError())
712       return std::make_pair(RHSResult, RemainingExpr);
713 
714     // This is a binary expression - evaluate and try to continue as a
715     // complex expr.
716     EvalResult ThisResult(computeBinOpResult(BinOp, LHSResult, RHSResult));
717 
718     return evalComplexExpr(std::make_pair(ThisResult, RemainingExpr), PCtx);
719   }
720 
721   bool decodeInst(StringRef Symbol, MCInst &Inst, uint64_t &Size,
722                   int64_t Offset) const {
723     auto TT = Checker.getTripleForSymbol(Checker.getTargetFlag(Symbol));
724     auto TI = getTargetInfo(TT, Checker.getCPU(), Checker.getFeatures());
725 
726     if (auto E = TI.takeError()) {
727       errs() << "Error obtaining disassembler: " << toString(std::move(E))
728              << "\n";
729       return false;
730     }
731 
732     StringRef SymbolMem = Checker.getSymbolContent(Symbol);
733     ArrayRef<uint8_t> SymbolBytes(SymbolMem.bytes_begin() + Offset,
734                                   SymbolMem.size() - Offset);
735 
736     MCDisassembler::DecodeStatus S =
737         TI->Disassembler->getInstruction(Inst, Size, SymbolBytes, 0, nulls());
738 
739     return (S == MCDisassembler::Success);
740   }
741 
742   Expected<TargetInfo> getTargetInfo(const Triple &TT, const StringRef &CPU,
743                                      const SubtargetFeatures &TF) const {
744 
745     auto TripleName = TT.str();
746     std::string ErrorStr;
747     const Target *TheTarget =
748         TargetRegistry::lookupTarget(TripleName, ErrorStr);
749     if (!TheTarget)
750       return make_error<StringError>("Error accessing target '" + TripleName +
751                                          "': " + ErrorStr,
752                                      inconvertibleErrorCode());
753 
754     std::unique_ptr<MCSubtargetInfo> STI(
755         TheTarget->createMCSubtargetInfo(TripleName, CPU, TF.getString()));
756     if (!STI)
757       return make_error<StringError>("Unable to create subtarget for " +
758                                          TripleName,
759                                      inconvertibleErrorCode());
760 
761     std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
762     if (!MRI)
763       return make_error<StringError>("Unable to create target register info "
764                                      "for " +
765                                          TripleName,
766                                      inconvertibleErrorCode());
767 
768     MCTargetOptions MCOptions;
769     std::unique_ptr<MCAsmInfo> MAI(
770         TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
771     if (!MAI)
772       return make_error<StringError>("Unable to create target asm info " +
773                                          TripleName,
774                                      inconvertibleErrorCode());
775 
776     auto Ctx = std::make_unique<MCContext>(Triple(TripleName), MAI.get(),
777                                            MRI.get(), STI.get());
778 
779     std::unique_ptr<MCDisassembler> Disassembler(
780         TheTarget->createMCDisassembler(*STI, *Ctx));
781     if (!Disassembler)
782       return make_error<StringError>("Unable to create disassembler for " +
783                                          TripleName,
784                                      inconvertibleErrorCode());
785 
786     std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());
787     if (!MII)
788       return make_error<StringError>("Unable to create instruction info for" +
789                                          TripleName,
790                                      inconvertibleErrorCode());
791 
792     std::unique_ptr<MCInstPrinter> InstPrinter(TheTarget->createMCInstPrinter(
793         Triple(TripleName), 0, *MAI, *MII, *MRI));
794     if (!InstPrinter)
795       return make_error<StringError>(
796           "Unable to create instruction printer for" + TripleName,
797           inconvertibleErrorCode());
798 
799     return TargetInfo({TheTarget, std::move(STI), std::move(MRI),
800                        std::move(MAI), std::move(Ctx), std::move(Disassembler),
801                        std::move(MII), std::move(InstPrinter)});
802   }
803 };
804 } // namespace llvm
805 
806 RuntimeDyldCheckerImpl::RuntimeDyldCheckerImpl(
807     IsSymbolValidFunction IsSymbolValid, GetSymbolInfoFunction GetSymbolInfo,
808     GetSectionInfoFunction GetSectionInfo, GetStubInfoFunction GetStubInfo,
809     GetGOTInfoFunction GetGOTInfo, llvm::endianness Endianness, Triple TT,
810     StringRef CPU, SubtargetFeatures TF, raw_ostream &ErrStream)
811     : IsSymbolValid(std::move(IsSymbolValid)),
812       GetSymbolInfo(std::move(GetSymbolInfo)),
813       GetSectionInfo(std::move(GetSectionInfo)),
814       GetStubInfo(std::move(GetStubInfo)), GetGOTInfo(std::move(GetGOTInfo)),
815       Endianness(Endianness), TT(std::move(TT)), CPU(std::move(CPU)),
816       TF(std::move(TF)), ErrStream(ErrStream) {}
817 
818 bool RuntimeDyldCheckerImpl::check(StringRef CheckExpr) const {
819   CheckExpr = CheckExpr.trim();
820   LLVM_DEBUG(dbgs() << "RuntimeDyldChecker: Checking '" << CheckExpr
821                     << "'...\n");
822   RuntimeDyldCheckerExprEval P(*this, ErrStream);
823   bool Result = P.evaluate(CheckExpr);
824   (void)Result;
825   LLVM_DEBUG(dbgs() << "RuntimeDyldChecker: '" << CheckExpr << "' "
826                     << (Result ? "passed" : "FAILED") << ".\n");
827   return Result;
828 }
829 
830 bool RuntimeDyldCheckerImpl::checkAllRulesInBuffer(StringRef RulePrefix,
831                                                    MemoryBuffer *MemBuf) const {
832   bool DidAllTestsPass = true;
833   unsigned NumRules = 0;
834 
835   std::string CheckExpr;
836   const char *LineStart = MemBuf->getBufferStart();
837 
838   // Eat whitespace.
839   while (LineStart != MemBuf->getBufferEnd() && isSpace(*LineStart))
840     ++LineStart;
841 
842   while (LineStart != MemBuf->getBufferEnd() && *LineStart != '\0') {
843     const char *LineEnd = LineStart;
844     while (LineEnd != MemBuf->getBufferEnd() && *LineEnd != '\r' &&
845            *LineEnd != '\n')
846       ++LineEnd;
847 
848     StringRef Line(LineStart, LineEnd - LineStart);
849     if (Line.starts_with(RulePrefix))
850       CheckExpr += Line.substr(RulePrefix.size()).str();
851 
852     // If there's a check expr string...
853     if (!CheckExpr.empty()) {
854       // ... and it's complete then run it, otherwise remove the trailer '\'.
855       if (CheckExpr.back() != '\\') {
856         DidAllTestsPass &= check(CheckExpr);
857         CheckExpr.clear();
858         ++NumRules;
859       } else
860         CheckExpr.pop_back();
861     }
862 
863     // Eat whitespace.
864     LineStart = LineEnd;
865     while (LineStart != MemBuf->getBufferEnd() && isSpace(*LineStart))
866       ++LineStart;
867   }
868   return DidAllTestsPass && (NumRules != 0);
869 }
870 
871 bool RuntimeDyldCheckerImpl::isSymbolValid(StringRef Symbol) const {
872   return IsSymbolValid(Symbol);
873 }
874 
875 uint64_t RuntimeDyldCheckerImpl::getSymbolLocalAddr(StringRef Symbol) const {
876   auto SymInfo = GetSymbolInfo(Symbol);
877   if (!SymInfo) {
878     logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
879     return 0;
880   }
881 
882   if (SymInfo->isZeroFill())
883     return 0;
884 
885   return static_cast<uint64_t>(
886       reinterpret_cast<uintptr_t>(SymInfo->getContent().data()));
887 }
888 
889 uint64_t RuntimeDyldCheckerImpl::getSymbolRemoteAddr(StringRef Symbol) const {
890   auto SymInfo = GetSymbolInfo(Symbol);
891   if (!SymInfo) {
892     logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
893     return 0;
894   }
895 
896   return SymInfo->getTargetAddress();
897 }
898 
899 uint64_t RuntimeDyldCheckerImpl::readMemoryAtAddr(uint64_t SrcAddr,
900                                                   unsigned Size) const {
901   uintptr_t PtrSizedAddr = static_cast<uintptr_t>(SrcAddr);
902   assert(PtrSizedAddr == SrcAddr && "Linker memory pointer out-of-range.");
903   void *Ptr = reinterpret_cast<void*>(PtrSizedAddr);
904 
905   switch (Size) {
906   case 1:
907     return support::endian::read<uint8_t>(Ptr, Endianness);
908   case 2:
909     return support::endian::read<uint16_t>(Ptr, Endianness);
910   case 4:
911     return support::endian::read<uint32_t>(Ptr, Endianness);
912   case 8:
913     return support::endian::read<uint64_t>(Ptr, Endianness);
914   }
915   llvm_unreachable("Unsupported read size");
916 }
917 
918 StringRef RuntimeDyldCheckerImpl::getSymbolContent(StringRef Symbol) const {
919   auto SymInfo = GetSymbolInfo(Symbol);
920   if (!SymInfo) {
921     logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
922     return StringRef();
923   }
924   return {SymInfo->getContent().data(), SymInfo->getContent().size()};
925 }
926 
927 TargetFlagsType RuntimeDyldCheckerImpl::getTargetFlag(StringRef Symbol) const {
928   auto SymInfo = GetSymbolInfo(Symbol);
929   if (!SymInfo) {
930     logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
931     return TargetFlagsType{};
932   }
933   return SymInfo->getTargetFlags();
934 }
935 
936 Triple
937 RuntimeDyldCheckerImpl::getTripleForSymbol(TargetFlagsType Flag) const {
938   Triple TheTriple = TT;
939 
940   switch (TT.getArch()) {
941   case Triple::ArchType::arm:
942     if (~Flag & 0x1)
943       return TT;
944     TheTriple.setArchName((Twine("thumb") + TT.getArchName().substr(3)).str());
945     return TheTriple;
946   case Triple::ArchType::thumb:
947     if (Flag & 0x1)
948       return TT;
949     TheTriple.setArchName((Twine("arm") + TT.getArchName().substr(5)).str());
950     return TheTriple;
951 
952   default:
953     return TT;
954   }
955 }
956 
957 std::pair<uint64_t, std::string> RuntimeDyldCheckerImpl::getSectionAddr(
958     StringRef FileName, StringRef SectionName, bool IsInsideLoad) const {
959 
960   auto SecInfo = GetSectionInfo(FileName, SectionName);
961   if (!SecInfo) {
962     std::string ErrMsg;
963     {
964       raw_string_ostream ErrMsgStream(ErrMsg);
965       logAllUnhandledErrors(SecInfo.takeError(), ErrMsgStream,
966                             "RTDyldChecker: ");
967     }
968     return std::make_pair(0, std::move(ErrMsg));
969   }
970 
971   // If this address is being looked up in "load" mode, return the content
972   // pointer, otherwise return the target address.
973 
974   uint64_t Addr = 0;
975 
976   if (IsInsideLoad) {
977     if (SecInfo->isZeroFill())
978       Addr = 0;
979     else
980       Addr = pointerToJITTargetAddress(SecInfo->getContent().data());
981   } else
982     Addr = SecInfo->getTargetAddress();
983 
984   return std::make_pair(Addr, "");
985 }
986 
987 std::pair<uint64_t, std::string> RuntimeDyldCheckerImpl::getStubOrGOTAddrFor(
988     StringRef StubContainerName, StringRef SymbolName, bool IsInsideLoad,
989     bool IsStubAddr) const {
990 
991   auto StubInfo = IsStubAddr ? GetStubInfo(StubContainerName, SymbolName)
992                              : GetGOTInfo(StubContainerName, SymbolName);
993 
994   if (!StubInfo) {
995     std::string ErrMsg;
996     {
997       raw_string_ostream ErrMsgStream(ErrMsg);
998       logAllUnhandledErrors(StubInfo.takeError(), ErrMsgStream,
999                             "RTDyldChecker: ");
1000     }
1001     return std::make_pair((uint64_t)0, std::move(ErrMsg));
1002   }
1003 
1004   uint64_t Addr = 0;
1005 
1006   if (IsInsideLoad) {
1007     if (StubInfo->isZeroFill())
1008       return std::make_pair((uint64_t)0, "Detected zero-filled stub/GOT entry");
1009     Addr = pointerToJITTargetAddress(StubInfo->getContent().data());
1010   } else
1011     Addr = StubInfo->getTargetAddress();
1012 
1013   return std::make_pair(Addr, "");
1014 }
1015 
1016 RuntimeDyldChecker::RuntimeDyldChecker(
1017     IsSymbolValidFunction IsSymbolValid, GetSymbolInfoFunction GetSymbolInfo,
1018     GetSectionInfoFunction GetSectionInfo, GetStubInfoFunction GetStubInfo,
1019     GetGOTInfoFunction GetGOTInfo, llvm::endianness Endianness, Triple TT,
1020     StringRef CPU, SubtargetFeatures TF, raw_ostream &ErrStream)
1021     : Impl(::std::make_unique<RuntimeDyldCheckerImpl>(
1022           std::move(IsSymbolValid), std::move(GetSymbolInfo),
1023           std::move(GetSectionInfo), std::move(GetStubInfo),
1024           std::move(GetGOTInfo), Endianness, std::move(TT), std::move(CPU),
1025           std::move(TF), ErrStream)) {}
1026 
1027 RuntimeDyldChecker::~RuntimeDyldChecker() = default;
1028 
1029 bool RuntimeDyldChecker::check(StringRef CheckExpr) const {
1030   return Impl->check(CheckExpr);
1031 }
1032 
1033 bool RuntimeDyldChecker::checkAllRulesInBuffer(StringRef RulePrefix,
1034                                                MemoryBuffer *MemBuf) const {
1035   return Impl->checkAllRulesInBuffer(RulePrefix, MemBuf);
1036 }
1037 
1038 std::pair<uint64_t, std::string>
1039 RuntimeDyldChecker::getSectionAddr(StringRef FileName, StringRef SectionName,
1040                                    bool LocalAddress) {
1041   return Impl->getSectionAddr(FileName, SectionName, LocalAddress);
1042 }
1043