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      1 //===- FaultMaps.cpp ------------------------------------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #include "llvm/CodeGen/FaultMaps.h"
     11 #include "llvm/ADT/Twine.h"
     12 #include "llvm/CodeGen/AsmPrinter.h"
     13 #include "llvm/MC/MCContext.h"
     14 #include "llvm/MC/MCExpr.h"
     15 #include "llvm/MC/MCObjectFileInfo.h"
     16 #include "llvm/MC/MCStreamer.h"
     17 #include "llvm/Support/Debug.h"
     18 #include "llvm/Support/ErrorHandling.h"
     19 #include "llvm/Support/Format.h"
     20 #include "llvm/Support/raw_ostream.h"
     21 
     22 using namespace llvm;
     23 
     24 #define DEBUG_TYPE "faultmaps"
     25 
     26 static const int FaultMapVersion = 1;
     27 const char *FaultMaps::WFMP = "Fault Maps: ";
     28 
     29 FaultMaps::FaultMaps(AsmPrinter &AP) : AP(AP) {}
     30 
     31 void FaultMaps::recordFaultingOp(FaultKind FaultTy,
     32                                  const MCSymbol *HandlerLabel) {
     33   MCContext &OutContext = AP.OutStreamer->getContext();
     34   MCSymbol *FaultingLabel = OutContext.createTempSymbol();
     35 
     36   AP.OutStreamer->EmitLabel(FaultingLabel);
     37 
     38   const MCExpr *FaultingOffset = MCBinaryExpr::createSub(
     39       MCSymbolRefExpr::create(FaultingLabel, OutContext),
     40       MCSymbolRefExpr::create(AP.CurrentFnSymForSize, OutContext), OutContext);
     41 
     42   const MCExpr *HandlerOffset = MCBinaryExpr::createSub(
     43       MCSymbolRefExpr::create(HandlerLabel, OutContext),
     44       MCSymbolRefExpr::create(AP.CurrentFnSymForSize, OutContext), OutContext);
     45 
     46   FunctionInfos[AP.CurrentFnSym].emplace_back(FaultTy, FaultingOffset,
     47                                               HandlerOffset);
     48 }
     49 
     50 void FaultMaps::serializeToFaultMapSection() {
     51   if (FunctionInfos.empty())
     52     return;
     53 
     54   MCContext &OutContext = AP.OutStreamer->getContext();
     55   MCStreamer &OS = *AP.OutStreamer;
     56 
     57   // Create the section.
     58   MCSection *FaultMapSection =
     59       OutContext.getObjectFileInfo()->getFaultMapSection();
     60   OS.SwitchSection(FaultMapSection);
     61 
     62   // Emit a dummy symbol to force section inclusion.
     63   OS.EmitLabel(OutContext.getOrCreateSymbol(Twine("__LLVM_FaultMaps")));
     64 
     65   LLVM_DEBUG(dbgs() << "********** Fault Map Output **********\n");
     66 
     67   // Header
     68   OS.EmitIntValue(FaultMapVersion, 1); // Version.
     69   OS.EmitIntValue(0, 1);               // Reserved.
     70   OS.EmitIntValue(0, 2);               // Reserved.
     71 
     72   LLVM_DEBUG(dbgs() << WFMP << "#functions = " << FunctionInfos.size() << "\n");
     73   OS.EmitIntValue(FunctionInfos.size(), 4);
     74 
     75   LLVM_DEBUG(dbgs() << WFMP << "functions:\n");
     76 
     77   for (const auto &FFI : FunctionInfos)
     78     emitFunctionInfo(FFI.first, FFI.second);
     79 }
     80 
     81 void FaultMaps::emitFunctionInfo(const MCSymbol *FnLabel,
     82                                  const FunctionFaultInfos &FFI) {
     83   MCStreamer &OS = *AP.OutStreamer;
     84 
     85   LLVM_DEBUG(dbgs() << WFMP << "  function addr: " << *FnLabel << "\n");
     86   OS.EmitSymbolValue(FnLabel, 8);
     87 
     88   LLVM_DEBUG(dbgs() << WFMP << "  #faulting PCs: " << FFI.size() << "\n");
     89   OS.EmitIntValue(FFI.size(), 4);
     90 
     91   OS.EmitIntValue(0, 4); // Reserved
     92 
     93   for (auto &Fault : FFI) {
     94     LLVM_DEBUG(dbgs() << WFMP << "    fault type: "
     95                       << faultTypeToString(Fault.Kind) << "\n");
     96     OS.EmitIntValue(Fault.Kind, 4);
     97 
     98     LLVM_DEBUG(dbgs() << WFMP << "    faulting PC offset: "
     99                       << *Fault.FaultingOffsetExpr << "\n");
    100     OS.EmitValue(Fault.FaultingOffsetExpr, 4);
    101 
    102     LLVM_DEBUG(dbgs() << WFMP << "    fault handler PC offset: "
    103                       << *Fault.HandlerOffsetExpr << "\n");
    104     OS.EmitValue(Fault.HandlerOffsetExpr, 4);
    105   }
    106 }
    107 
    108 const char *FaultMaps::faultTypeToString(FaultMaps::FaultKind FT) {
    109   switch (FT) {
    110   default:
    111     llvm_unreachable("unhandled fault type!");
    112   case FaultMaps::FaultingLoad:
    113     return "FaultingLoad";
    114   case FaultMaps::FaultingLoadStore:
    115     return "FaultingLoadStore";
    116   case FaultMaps::FaultingStore:
    117     return "FaultingStore";
    118   }
    119 }
    120 
    121 raw_ostream &llvm::
    122 operator<<(raw_ostream &OS,
    123            const FaultMapParser::FunctionFaultInfoAccessor &FFI) {
    124   OS << "Fault kind: "
    125      << FaultMaps::faultTypeToString((FaultMaps::FaultKind)FFI.getFaultKind())
    126      << ", faulting PC offset: " << FFI.getFaultingPCOffset()
    127      << ", handling PC offset: " << FFI.getHandlerPCOffset();
    128   return OS;
    129 }
    130 
    131 raw_ostream &llvm::
    132 operator<<(raw_ostream &OS, const FaultMapParser::FunctionInfoAccessor &FI) {
    133   OS << "FunctionAddress: " << format_hex(FI.getFunctionAddr(), 8)
    134      << ", NumFaultingPCs: " << FI.getNumFaultingPCs() << "\n";
    135   for (unsigned i = 0, e = FI.getNumFaultingPCs(); i != e; ++i)
    136     OS << FI.getFunctionFaultInfoAt(i) << "\n";
    137   return OS;
    138 }
    139 
    140 raw_ostream &llvm::operator<<(raw_ostream &OS, const FaultMapParser &FMP) {
    141   OS << "Version: " << format_hex(FMP.getFaultMapVersion(), 2) << "\n";
    142   OS << "NumFunctions: " << FMP.getNumFunctions() << "\n";
    143 
    144   if (FMP.getNumFunctions() == 0)
    145     return OS;
    146 
    147   FaultMapParser::FunctionInfoAccessor FI;
    148 
    149   for (unsigned i = 0, e = FMP.getNumFunctions(); i != e; ++i) {
    150     FI = (i == 0) ? FMP.getFirstFunctionInfo() : FI.getNextFunctionInfo();
    151     OS << FI;
    152   }
    153 
    154   return OS;
    155 }
    156