xref: /freebsd/contrib/llvm-project/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp (revision aa1a8ff2d6dbc51ef058f46f3db5a8bb77967145) 
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     // Parse optional parameter to filter by stub kind
404     StringRef KindNameFilter;
405     if (RemainingExpr.starts_with(",")) {
406       RemainingExpr = RemainingExpr.substr(1).ltrim();
407       size_t ClosingBracket = RemainingExpr.find(")");
408       KindNameFilter = RemainingExpr.substr(0, ClosingBracket);
409       RemainingExpr = RemainingExpr.substr(ClosingBracket);
410     }
411 
412     if (!RemainingExpr.starts_with(")"))
413       return std::make_pair(
414           unexpectedToken(RemainingExpr, Expr, "expected ')'"), "");
415     RemainingExpr = RemainingExpr.substr(1).ltrim();
416 
417     uint64_t StubAddr;
418     std::string ErrorMsg;
419     std::tie(StubAddr, ErrorMsg) =
420         Checker.getStubOrGOTAddrFor(StubContainerName, Symbol, KindNameFilter,
421                                     PCtx.IsInsideLoad, IsStubAddr);
422 
423     if (ErrorMsg != "")
424       return std::make_pair(EvalResult(ErrorMsg), "");
425 
426     return std::make_pair(EvalResult(StubAddr), RemainingExpr);
427   }
428 
429   std::pair<EvalResult, StringRef> evalSectionAddr(StringRef Expr,
430                                                    ParseContext PCtx) const {
431     if (!Expr.starts_with("("))
432       return std::make_pair(unexpectedToken(Expr, Expr, "expected '('"), "");
433     StringRef RemainingExpr = Expr.substr(1).ltrim();
434 
435     // Handle file-name specially, as it may contain characters that aren't
436     // legal for symbols.
437     StringRef FileName;
438     size_t ComaIdx = RemainingExpr.find(',');
439     FileName = RemainingExpr.substr(0, ComaIdx).rtrim();
440     RemainingExpr = RemainingExpr.substr(ComaIdx).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     StringRef SectionName;
448     size_t CloseParensIdx = RemainingExpr.find(')');
449     SectionName = RemainingExpr.substr(0, CloseParensIdx).rtrim();
450     RemainingExpr = RemainingExpr.substr(CloseParensIdx).ltrim();
451 
452     if (!RemainingExpr.starts_with(")"))
453       return std::make_pair(
454           unexpectedToken(RemainingExpr, Expr, "expected ')'"), "");
455     RemainingExpr = RemainingExpr.substr(1).ltrim();
456 
457     uint64_t StubAddr;
458     std::string ErrorMsg;
459     std::tie(StubAddr, ErrorMsg) = Checker.getSectionAddr(
460         FileName, SectionName, PCtx.IsInsideLoad);
461 
462     if (ErrorMsg != "")
463       return std::make_pair(EvalResult(ErrorMsg), "");
464 
465     return std::make_pair(EvalResult(StubAddr), RemainingExpr);
466   }
467 
468   // Evaluate an identifier expr, which may be a symbol, or a call to
469   // one of the builtin functions: get_insn_opcode or get_insn_length.
470   // Return the result, plus the expression remaining to be parsed.
471   std::pair<EvalResult, StringRef> evalIdentifierExpr(StringRef Expr,
472                                                       ParseContext PCtx) const {
473     StringRef Symbol;
474     StringRef RemainingExpr;
475     std::tie(Symbol, RemainingExpr) = parseSymbol(Expr);
476 
477     // Check for builtin function calls.
478     if (Symbol == "decode_operand")
479       return evalDecodeOperand(RemainingExpr);
480     else if (Symbol == "next_pc")
481       return evalNextPC(RemainingExpr, PCtx);
482     else if (Symbol == "stub_addr")
483       return evalStubOrGOTAddr(RemainingExpr, PCtx, true);
484     else if (Symbol == "got_addr")
485       return evalStubOrGOTAddr(RemainingExpr, PCtx, false);
486     else if (Symbol == "section_addr")
487       return evalSectionAddr(RemainingExpr, PCtx);
488 
489     if (!Checker.isSymbolValid(Symbol)) {
490       std::string ErrMsg("No known address for symbol '");
491       ErrMsg += Symbol;
492       ErrMsg += "'";
493       if (Symbol.starts_with("L"))
494         ErrMsg += " (this appears to be an assembler local label - "
495                   " perhaps drop the 'L'?)";
496 
497       return std::make_pair(EvalResult(ErrMsg), "");
498     }
499 
500     // The value for the symbol depends on the context we're evaluating in:
501     // Inside a load this is the address in the linker's memory, outside a
502     // load it's the address in the target processes memory.
503     uint64_t Value = PCtx.IsInsideLoad ? Checker.getSymbolLocalAddr(Symbol)
504                                        : Checker.getSymbolRemoteAddr(Symbol);
505 
506     // Looks like a plain symbol reference.
507     return std::make_pair(EvalResult(Value), RemainingExpr);
508   }
509 
510   // Parse a number (hexadecimal or decimal) and return a (string, string)
511   // pair representing the number and the expression remaining to be parsed.
512   std::pair<StringRef, StringRef> parseNumberString(StringRef Expr) const {
513     size_t FirstNonDigit = StringRef::npos;
514     if (Expr.starts_with("0x")) {
515       FirstNonDigit = Expr.find_first_not_of("0123456789abcdefABCDEF", 2);
516       if (FirstNonDigit == StringRef::npos)
517         FirstNonDigit = Expr.size();
518     } else {
519       FirstNonDigit = Expr.find_first_not_of("0123456789");
520       if (FirstNonDigit == StringRef::npos)
521         FirstNonDigit = Expr.size();
522     }
523     return std::make_pair(Expr.substr(0, FirstNonDigit),
524                           Expr.substr(FirstNonDigit));
525   }
526 
527   // Evaluate a constant numeric expression (hexadecimal or decimal) and
528   // return a pair containing the result, and the expression remaining to be
529   // evaluated.
530   std::pair<EvalResult, StringRef> evalNumberExpr(StringRef Expr) const {
531     StringRef ValueStr;
532     StringRef RemainingExpr;
533     std::tie(ValueStr, RemainingExpr) = parseNumberString(Expr);
534 
535     if (ValueStr.empty() || !isdigit(ValueStr[0]))
536       return std::make_pair(
537           unexpectedToken(RemainingExpr, RemainingExpr, "expected number"), "");
538     uint64_t Value;
539     ValueStr.getAsInteger(0, Value);
540     return std::make_pair(EvalResult(Value), RemainingExpr);
541   }
542 
543   // Evaluate an expression of the form "(<expr>)" and return a pair
544   // containing the result of evaluating <expr>, plus the expression
545   // remaining to be parsed.
546   std::pair<EvalResult, StringRef> evalParensExpr(StringRef Expr,
547                                                   ParseContext PCtx) const {
548     assert(Expr.starts_with("(") && "Not a parenthesized expression");
549     EvalResult SubExprResult;
550     StringRef RemainingExpr;
551     std::tie(SubExprResult, RemainingExpr) =
552         evalComplexExpr(evalSimpleExpr(Expr.substr(1).ltrim(), PCtx), PCtx);
553     if (SubExprResult.hasError())
554       return std::make_pair(SubExprResult, "");
555     if (!RemainingExpr.starts_with(")"))
556       return std::make_pair(
557           unexpectedToken(RemainingExpr, Expr, "expected ')'"), "");
558     RemainingExpr = RemainingExpr.substr(1).ltrim();
559     return std::make_pair(SubExprResult, RemainingExpr);
560   }
561 
562   // Evaluate an expression in one of the following forms:
563   //   *{<number>}<expr>
564   // Return a pair containing the result, plus the expression remaining to be
565   // parsed.
566   std::pair<EvalResult, StringRef> evalLoadExpr(StringRef Expr) const {
567     assert(Expr.starts_with("*") && "Not a load expression");
568     StringRef RemainingExpr = Expr.substr(1).ltrim();
569 
570     // Parse read size.
571     if (!RemainingExpr.starts_with("{"))
572       return std::make_pair(EvalResult("Expected '{' following '*'."), "");
573     RemainingExpr = RemainingExpr.substr(1).ltrim();
574     EvalResult ReadSizeExpr;
575     std::tie(ReadSizeExpr, RemainingExpr) = evalNumberExpr(RemainingExpr);
576     if (ReadSizeExpr.hasError())
577       return std::make_pair(ReadSizeExpr, RemainingExpr);
578     uint64_t ReadSize = ReadSizeExpr.getValue();
579     if (ReadSize < 1 || ReadSize > 8)
580       return std::make_pair(EvalResult("Invalid size for dereference."), "");
581     if (!RemainingExpr.starts_with("}"))
582       return std::make_pair(EvalResult("Missing '}' for dereference."), "");
583     RemainingExpr = RemainingExpr.substr(1).ltrim();
584 
585     // Evaluate the expression representing the load address.
586     ParseContext LoadCtx(true);
587     EvalResult LoadAddrExprResult;
588     std::tie(LoadAddrExprResult, RemainingExpr) =
589         evalComplexExpr(evalSimpleExpr(RemainingExpr, LoadCtx), LoadCtx);
590 
591     if (LoadAddrExprResult.hasError())
592       return std::make_pair(LoadAddrExprResult, "");
593 
594     uint64_t LoadAddr = LoadAddrExprResult.getValue();
595 
596     // If there is no error but the content pointer is null then this is a
597     // zero-fill symbol/section.
598     if (LoadAddr == 0)
599       return std::make_pair(0, RemainingExpr);
600 
601     return std::make_pair(
602         EvalResult(Checker.readMemoryAtAddr(LoadAddr, ReadSize)),
603         RemainingExpr);
604   }
605 
606   // Evaluate a "simple" expression. This is any expression that _isn't_ an
607   // un-parenthesized binary expression.
608   //
609   // "Simple" expressions can be optionally bit-sliced. See evalSlicedExpr.
610   //
611   // Returns a pair containing the result of the evaluation, plus the
612   // expression remaining to be parsed.
613   std::pair<EvalResult, StringRef> evalSimpleExpr(StringRef Expr,
614                                                   ParseContext PCtx) const {
615     EvalResult SubExprResult;
616     StringRef RemainingExpr;
617 
618     if (Expr.empty())
619       return std::make_pair(EvalResult("Unexpected end of expression"), "");
620 
621     if (Expr[0] == '(')
622       std::tie(SubExprResult, RemainingExpr) = evalParensExpr(Expr, PCtx);
623     else if (Expr[0] == '*')
624       std::tie(SubExprResult, RemainingExpr) = evalLoadExpr(Expr);
625     else if (isalpha(Expr[0]) || Expr[0] == '_')
626       std::tie(SubExprResult, RemainingExpr) = evalIdentifierExpr(Expr, PCtx);
627     else if (isdigit(Expr[0]))
628       std::tie(SubExprResult, RemainingExpr) = evalNumberExpr(Expr);
629     else
630       return std::make_pair(
631           unexpectedToken(Expr, Expr,
632                           "expected '(', '*', identifier, or number"), "");
633 
634     if (SubExprResult.hasError())
635       return std::make_pair(SubExprResult, RemainingExpr);
636 
637     // Evaluate bit-slice if present.
638     if (RemainingExpr.starts_with("["))
639       std::tie(SubExprResult, RemainingExpr) =
640           evalSliceExpr(std::make_pair(SubExprResult, RemainingExpr));
641 
642     return std::make_pair(SubExprResult, RemainingExpr);
643   }
644 
645   // Evaluate a bit-slice of an expression.
646   // A bit-slice has the form "<expr>[high:low]". The result of evaluating a
647   // slice is the bits between high and low (inclusive) in the original
648   // expression, right shifted so that the "low" bit is in position 0 in the
649   // result.
650   // Returns a pair containing the result of the slice operation, plus the
651   // expression remaining to be parsed.
652   std::pair<EvalResult, StringRef>
653   evalSliceExpr(const std::pair<EvalResult, StringRef> &Ctx) const {
654     EvalResult SubExprResult;
655     StringRef RemainingExpr;
656     std::tie(SubExprResult, RemainingExpr) = Ctx;
657 
658     assert(RemainingExpr.starts_with("[") && "Not a slice expr.");
659     RemainingExpr = RemainingExpr.substr(1).ltrim();
660 
661     EvalResult HighBitExpr;
662     std::tie(HighBitExpr, RemainingExpr) = evalNumberExpr(RemainingExpr);
663 
664     if (HighBitExpr.hasError())
665       return std::make_pair(HighBitExpr, RemainingExpr);
666 
667     if (!RemainingExpr.starts_with(":"))
668       return std::make_pair(
669           unexpectedToken(RemainingExpr, RemainingExpr, "expected ':'"), "");
670     RemainingExpr = RemainingExpr.substr(1).ltrim();
671 
672     EvalResult LowBitExpr;
673     std::tie(LowBitExpr, RemainingExpr) = evalNumberExpr(RemainingExpr);
674 
675     if (LowBitExpr.hasError())
676       return std::make_pair(LowBitExpr, RemainingExpr);
677 
678     if (!RemainingExpr.starts_with("]"))
679       return std::make_pair(
680           unexpectedToken(RemainingExpr, RemainingExpr, "expected ']'"), "");
681     RemainingExpr = RemainingExpr.substr(1).ltrim();
682 
683     unsigned HighBit = HighBitExpr.getValue();
684     unsigned LowBit = LowBitExpr.getValue();
685     uint64_t Mask = ((uint64_t)1 << (HighBit - LowBit + 1)) - 1;
686     uint64_t SlicedValue = (SubExprResult.getValue() >> LowBit) & Mask;
687     return std::make_pair(EvalResult(SlicedValue), RemainingExpr);
688   }
689 
690   // Evaluate a "complex" expression.
691   // Takes an already evaluated subexpression and checks for the presence of a
692   // binary operator, computing the result of the binary operation if one is
693   // found. Used to make arithmetic expressions left-associative.
694   // Returns a pair containing the ultimate result of evaluating the
695   // expression, plus the expression remaining to be evaluated.
696   std::pair<EvalResult, StringRef>
697   evalComplexExpr(const std::pair<EvalResult, StringRef> &LHSAndRemaining,
698                   ParseContext PCtx) const {
699     EvalResult LHSResult;
700     StringRef RemainingExpr;
701     std::tie(LHSResult, RemainingExpr) = LHSAndRemaining;
702 
703     // If there was an error, or there's nothing left to evaluate, return the
704     // result.
705     if (LHSResult.hasError() || RemainingExpr == "")
706       return std::make_pair(LHSResult, RemainingExpr);
707 
708     // Otherwise check if this is a binary expression.
709     BinOpToken BinOp;
710     std::tie(BinOp, RemainingExpr) = parseBinOpToken(RemainingExpr);
711 
712     // If this isn't a recognized expression just return.
713     if (BinOp == BinOpToken::Invalid)
714       return std::make_pair(LHSResult, RemainingExpr);
715 
716     // This is a recognized bin-op. Evaluate the RHS, then evaluate the binop.
717     EvalResult RHSResult;
718     std::tie(RHSResult, RemainingExpr) = evalSimpleExpr(RemainingExpr, PCtx);
719 
720     // If there was an error evaluating the RHS, return it.
721     if (RHSResult.hasError())
722       return std::make_pair(RHSResult, RemainingExpr);
723 
724     // This is a binary expression - evaluate and try to continue as a
725     // complex expr.
726     EvalResult ThisResult(computeBinOpResult(BinOp, LHSResult, RHSResult));
727 
728     return evalComplexExpr(std::make_pair(ThisResult, RemainingExpr), PCtx);
729   }
730 
731   bool decodeInst(StringRef Symbol, MCInst &Inst, uint64_t &Size,
732                   int64_t Offset) const {
733     auto TT = Checker.getTripleForSymbol(Checker.getTargetFlag(Symbol));
734     auto TI = getTargetInfo(TT, Checker.getCPU(), Checker.getFeatures());
735 
736     if (auto E = TI.takeError()) {
737       errs() << "Error obtaining disassembler: " << toString(std::move(E))
738              << "\n";
739       return false;
740     }
741 
742     StringRef SymbolMem = Checker.getSymbolContent(Symbol);
743     ArrayRef<uint8_t> SymbolBytes(SymbolMem.bytes_begin() + Offset,
744                                   SymbolMem.size() - Offset);
745 
746     MCDisassembler::DecodeStatus S =
747         TI->Disassembler->getInstruction(Inst, Size, SymbolBytes, 0, nulls());
748 
749     return (S == MCDisassembler::Success);
750   }
751 
752   Expected<TargetInfo> getTargetInfo(const Triple &TT, const StringRef &CPU,
753                                      const SubtargetFeatures &TF) const {
754 
755     auto TripleName = TT.str();
756     std::string ErrorStr;
757     const Target *TheTarget =
758         TargetRegistry::lookupTarget(TripleName, ErrorStr);
759     if (!TheTarget)
760       return make_error<StringError>("Error accessing target '" + TripleName +
761                                          "': " + ErrorStr,
762                                      inconvertibleErrorCode());
763 
764     std::unique_ptr<MCSubtargetInfo> STI(
765         TheTarget->createMCSubtargetInfo(TripleName, CPU, TF.getString()));
766     if (!STI)
767       return make_error<StringError>("Unable to create subtarget for " +
768                                          TripleName,
769                                      inconvertibleErrorCode());
770 
771     std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
772     if (!MRI)
773       return make_error<StringError>("Unable to create target register info "
774                                      "for " +
775                                          TripleName,
776                                      inconvertibleErrorCode());
777 
778     MCTargetOptions MCOptions;
779     std::unique_ptr<MCAsmInfo> MAI(
780         TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
781     if (!MAI)
782       return make_error<StringError>("Unable to create target asm info " +
783                                          TripleName,
784                                      inconvertibleErrorCode());
785 
786     auto Ctx = std::make_unique<MCContext>(Triple(TripleName), MAI.get(),
787                                            MRI.get(), STI.get());
788 
789     std::unique_ptr<MCDisassembler> Disassembler(
790         TheTarget->createMCDisassembler(*STI, *Ctx));
791     if (!Disassembler)
792       return make_error<StringError>("Unable to create disassembler for " +
793                                          TripleName,
794                                      inconvertibleErrorCode());
795 
796     std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());
797     if (!MII)
798       return make_error<StringError>("Unable to create instruction info for" +
799                                          TripleName,
800                                      inconvertibleErrorCode());
801 
802     std::unique_ptr<MCInstPrinter> InstPrinter(TheTarget->createMCInstPrinter(
803         Triple(TripleName), 0, *MAI, *MII, *MRI));
804     if (!InstPrinter)
805       return make_error<StringError>(
806           "Unable to create instruction printer for" + TripleName,
807           inconvertibleErrorCode());
808 
809     return TargetInfo({TheTarget, std::move(STI), std::move(MRI),
810                        std::move(MAI), std::move(Ctx), std::move(Disassembler),
811                        std::move(MII), std::move(InstPrinter)});
812   }
813 };
814 } // namespace llvm
815 
816 RuntimeDyldCheckerImpl::RuntimeDyldCheckerImpl(
817     IsSymbolValidFunction IsSymbolValid, GetSymbolInfoFunction GetSymbolInfo,
818     GetSectionInfoFunction GetSectionInfo, GetStubInfoFunction GetStubInfo,
819     GetGOTInfoFunction GetGOTInfo, llvm::endianness Endianness, Triple TT,
820     StringRef CPU, SubtargetFeatures TF, raw_ostream &ErrStream)
821     : IsSymbolValid(std::move(IsSymbolValid)),
822       GetSymbolInfo(std::move(GetSymbolInfo)),
823       GetSectionInfo(std::move(GetSectionInfo)),
824       GetStubInfo(std::move(GetStubInfo)), GetGOTInfo(std::move(GetGOTInfo)),
825       Endianness(Endianness), TT(std::move(TT)), CPU(std::move(CPU)),
826       TF(std::move(TF)), ErrStream(ErrStream) {}
827 
828 bool RuntimeDyldCheckerImpl::check(StringRef CheckExpr) const {
829   CheckExpr = CheckExpr.trim();
830   LLVM_DEBUG(dbgs() << "RuntimeDyldChecker: Checking '" << CheckExpr
831                     << "'...\n");
832   RuntimeDyldCheckerExprEval P(*this, ErrStream);
833   bool Result = P.evaluate(CheckExpr);
834   (void)Result;
835   LLVM_DEBUG(dbgs() << "RuntimeDyldChecker: '" << CheckExpr << "' "
836                     << (Result ? "passed" : "FAILED") << ".\n");
837   return Result;
838 }
839 
840 bool RuntimeDyldCheckerImpl::checkAllRulesInBuffer(StringRef RulePrefix,
841                                                    MemoryBuffer *MemBuf) const {
842   bool DidAllTestsPass = true;
843   unsigned NumRules = 0;
844 
845   std::string CheckExpr;
846   const char *LineStart = MemBuf->getBufferStart();
847 
848   // Eat whitespace.
849   while (LineStart != MemBuf->getBufferEnd() && isSpace(*LineStart))
850     ++LineStart;
851 
852   while (LineStart != MemBuf->getBufferEnd() && *LineStart != '\0') {
853     const char *LineEnd = LineStart;
854     while (LineEnd != MemBuf->getBufferEnd() && *LineEnd != '\r' &&
855            *LineEnd != '\n')
856       ++LineEnd;
857 
858     StringRef Line(LineStart, LineEnd - LineStart);
859     if (Line.starts_with(RulePrefix))
860       CheckExpr += Line.substr(RulePrefix.size()).str();
861 
862     // If there's a check expr string...
863     if (!CheckExpr.empty()) {
864       // ... and it's complete then run it, otherwise remove the trailer '\'.
865       if (CheckExpr.back() != '\\') {
866         DidAllTestsPass &= check(CheckExpr);
867         CheckExpr.clear();
868         ++NumRules;
869       } else
870         CheckExpr.pop_back();
871     }
872 
873     // Eat whitespace.
874     LineStart = LineEnd;
875     while (LineStart != MemBuf->getBufferEnd() && isSpace(*LineStart))
876       ++LineStart;
877   }
878   return DidAllTestsPass && (NumRules != 0);
879 }
880 
881 bool RuntimeDyldCheckerImpl::isSymbolValid(StringRef Symbol) const {
882   return IsSymbolValid(Symbol);
883 }
884 
885 uint64_t RuntimeDyldCheckerImpl::getSymbolLocalAddr(StringRef Symbol) const {
886   auto SymInfo = GetSymbolInfo(Symbol);
887   if (!SymInfo) {
888     logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
889     return 0;
890   }
891 
892   if (SymInfo->isZeroFill())
893     return 0;
894 
895   return static_cast<uint64_t>(
896       reinterpret_cast<uintptr_t>(SymInfo->getContent().data()));
897 }
898 
899 uint64_t RuntimeDyldCheckerImpl::getSymbolRemoteAddr(StringRef Symbol) const {
900   auto SymInfo = GetSymbolInfo(Symbol);
901   if (!SymInfo) {
902     logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
903     return 0;
904   }
905 
906   return SymInfo->getTargetAddress();
907 }
908 
909 uint64_t RuntimeDyldCheckerImpl::readMemoryAtAddr(uint64_t SrcAddr,
910                                                   unsigned Size) const {
911   uintptr_t PtrSizedAddr = static_cast<uintptr_t>(SrcAddr);
912   assert(PtrSizedAddr == SrcAddr && "Linker memory pointer out-of-range.");
913   void *Ptr = reinterpret_cast<void*>(PtrSizedAddr);
914 
915   switch (Size) {
916   case 1:
917     return support::endian::read<uint8_t>(Ptr, Endianness);
918   case 2:
919     return support::endian::read<uint16_t>(Ptr, Endianness);
920   case 4:
921     return support::endian::read<uint32_t>(Ptr, Endianness);
922   case 8:
923     return support::endian::read<uint64_t>(Ptr, Endianness);
924   }
925   llvm_unreachable("Unsupported read size");
926 }
927 
928 StringRef RuntimeDyldCheckerImpl::getSymbolContent(StringRef Symbol) const {
929   auto SymInfo = GetSymbolInfo(Symbol);
930   if (!SymInfo) {
931     logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
932     return StringRef();
933   }
934   return {SymInfo->getContent().data(), SymInfo->getContent().size()};
935 }
936 
937 TargetFlagsType RuntimeDyldCheckerImpl::getTargetFlag(StringRef Symbol) const {
938   auto SymInfo = GetSymbolInfo(Symbol);
939   if (!SymInfo) {
940     logAllUnhandledErrors(SymInfo.takeError(), errs(), "RTDyldChecker: ");
941     return TargetFlagsType{};
942   }
943   return SymInfo->getTargetFlags();
944 }
945 
946 Triple
947 RuntimeDyldCheckerImpl::getTripleForSymbol(TargetFlagsType Flag) const {
948   Triple TheTriple = TT;
949 
950   switch (TT.getArch()) {
951   case Triple::ArchType::arm:
952     if (~Flag & 0x1)
953       return TT;
954     TheTriple.setArchName((Twine("thumb") + TT.getArchName().substr(3)).str());
955     return TheTriple;
956   case Triple::ArchType::thumb:
957     if (Flag & 0x1)
958       return TT;
959     TheTriple.setArchName((Twine("arm") + TT.getArchName().substr(5)).str());
960     return TheTriple;
961 
962   default:
963     return TT;
964   }
965 }
966 
967 std::pair<uint64_t, std::string> RuntimeDyldCheckerImpl::getSectionAddr(
968     StringRef FileName, StringRef SectionName, bool IsInsideLoad) const {
969 
970   auto SecInfo = GetSectionInfo(FileName, SectionName);
971   if (!SecInfo) {
972     std::string ErrMsg;
973     {
974       raw_string_ostream ErrMsgStream(ErrMsg);
975       logAllUnhandledErrors(SecInfo.takeError(), ErrMsgStream,
976                             "RTDyldChecker: ");
977     }
978     return std::make_pair(0, std::move(ErrMsg));
979   }
980 
981   // If this address is being looked up in "load" mode, return the content
982   // pointer, otherwise return the target address.
983 
984   uint64_t Addr = 0;
985 
986   if (IsInsideLoad) {
987     if (SecInfo->isZeroFill())
988       Addr = 0;
989     else
990       Addr = pointerToJITTargetAddress(SecInfo->getContent().data());
991   } else
992     Addr = SecInfo->getTargetAddress();
993 
994   return std::make_pair(Addr, "");
995 }
996 
997 std::pair<uint64_t, std::string> RuntimeDyldCheckerImpl::getStubOrGOTAddrFor(
998     StringRef StubContainerName, StringRef SymbolName, StringRef StubKindFilter,
999     bool IsInsideLoad, bool IsStubAddr) const {
1000 
1001   assert((StubKindFilter.empty() || IsStubAddr) &&
1002          "Kind name filter only supported for stubs");
1003   auto StubInfo =
1004       IsStubAddr ? GetStubInfo(StubContainerName, SymbolName, StubKindFilter)
1005                  : GetGOTInfo(StubContainerName, SymbolName);
1006 
1007   if (!StubInfo) {
1008     std::string ErrMsg;
1009     {
1010       raw_string_ostream ErrMsgStream(ErrMsg);
1011       logAllUnhandledErrors(StubInfo.takeError(), ErrMsgStream,
1012                             "RTDyldChecker: ");
1013     }
1014     return std::make_pair((uint64_t)0, std::move(ErrMsg));
1015   }
1016 
1017   uint64_t Addr = 0;
1018 
1019   if (IsInsideLoad) {
1020     if (StubInfo->isZeroFill())
1021       return std::make_pair((uint64_t)0, "Detected zero-filled stub/GOT entry");
1022     Addr = pointerToJITTargetAddress(StubInfo->getContent().data());
1023   } else
1024     Addr = StubInfo->getTargetAddress();
1025 
1026   return std::make_pair(Addr, "");
1027 }
1028 
1029 RuntimeDyldChecker::RuntimeDyldChecker(
1030     IsSymbolValidFunction IsSymbolValid, GetSymbolInfoFunction GetSymbolInfo,
1031     GetSectionInfoFunction GetSectionInfo, GetStubInfoFunction GetStubInfo,
1032     GetGOTInfoFunction GetGOTInfo, llvm::endianness Endianness, Triple TT,
1033     StringRef CPU, SubtargetFeatures TF, raw_ostream &ErrStream)
1034     : Impl(::std::make_unique<RuntimeDyldCheckerImpl>(
1035           std::move(IsSymbolValid), std::move(GetSymbolInfo),
1036           std::move(GetSectionInfo), std::move(GetStubInfo),
1037           std::move(GetGOTInfo), Endianness, std::move(TT), std::move(CPU),
1038           std::move(TF), ErrStream)) {}
1039 
1040 RuntimeDyldChecker::~RuntimeDyldChecker() = default;
1041 
1042 bool RuntimeDyldChecker::check(StringRef CheckExpr) const {
1043   return Impl->check(CheckExpr);
1044 }
1045 
1046 bool RuntimeDyldChecker::checkAllRulesInBuffer(StringRef RulePrefix,
1047                                                MemoryBuffer *MemBuf) const {
1048   return Impl->checkAllRulesInBuffer(RulePrefix, MemBuf);
1049 }
1050 
1051 std::pair<uint64_t, std::string>
1052 RuntimeDyldChecker::getSectionAddr(StringRef FileName, StringRef SectionName,
1053                                    bool LocalAddress) {
1054   return Impl->getSectionAddr(FileName, SectionName, LocalAddress);
1055 }
1056