lib/ExecutionEngine/RuntimeDyld/RuntimeDyldChecker.cpp

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