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      1 //===-- OProfileJITEventListener.cpp - Tell OProfile about JITted code ----===//
      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 // This file defines a JITEventListener object that uses OProfileWrapper to tell
     11 // oprofile about JITted functions, including source line information.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "llvm/Config/config.h"
     16 #include "llvm/ExecutionEngine/JITEventListener.h"
     17 
     18 #define DEBUG_TYPE "oprofile-jit-event-listener"
     19 #include "llvm/DebugInfo.h"
     20 #include "llvm/IR/Function.h"
     21 #include "llvm/ADT/OwningPtr.h"
     22 #include "llvm/CodeGen/MachineFunction.h"
     23 #include "llvm/ExecutionEngine/OProfileWrapper.h"
     24 #include "llvm/Support/Debug.h"
     25 #include "llvm/Support/raw_ostream.h"
     26 #include "llvm/Support/Errno.h"
     27 #include "EventListenerCommon.h"
     28 
     29 #include <dirent.h>
     30 #include <fcntl.h>
     31 
     32 using namespace llvm;
     33 using namespace llvm::jitprofiling;
     34 
     35 namespace {
     36 
     37 class OProfileJITEventListener : public JITEventListener {
     38   OProfileWrapper& Wrapper;
     39 
     40   void initialize();
     41 
     42 public:
     43   OProfileJITEventListener(OProfileWrapper& LibraryWrapper)
     44   : Wrapper(LibraryWrapper) {
     45     initialize();
     46   }
     47 
     48   ~OProfileJITEventListener();
     49 
     50   virtual void NotifyFunctionEmitted(const Function &F,
     51                                 void *FnStart, size_t FnSize,
     52                                 const JITEvent_EmittedFunctionDetails &Details);
     53 
     54   virtual void NotifyFreeingMachineCode(void *OldPtr);
     55 };
     56 
     57 void OProfileJITEventListener::initialize() {
     58   if (!Wrapper.op_open_agent()) {
     59     const std::string err_str = sys::StrError();
     60     DEBUG(dbgs() << "Failed to connect to OProfile agent: " << err_str << "\n");
     61   } else {
     62     DEBUG(dbgs() << "Connected to OProfile agent.\n");
     63   }
     64 }
     65 
     66 OProfileJITEventListener::~OProfileJITEventListener() {
     67   if (Wrapper.isAgentAvailable()) {
     68     if (Wrapper.op_close_agent() == -1) {
     69       const std::string err_str = sys::StrError();
     70       DEBUG(dbgs() << "Failed to disconnect from OProfile agent: "
     71                    << err_str << "\n");
     72     } else {
     73       DEBUG(dbgs() << "Disconnected from OProfile agent.\n");
     74     }
     75   }
     76 }
     77 
     78 static debug_line_info LineStartToOProfileFormat(
     79     const MachineFunction &MF, FilenameCache &Filenames,
     80     uintptr_t Address, DebugLoc Loc) {
     81   debug_line_info Result;
     82   Result.vma = Address;
     83   Result.lineno = Loc.getLine();
     84   Result.filename = Filenames.getFilename(
     85     Loc.getScope(MF.getFunction()->getContext()));
     86   DEBUG(dbgs() << "Mapping " << reinterpret_cast<void*>(Result.vma) << " to "
     87                << Result.filename << ":" << Result.lineno << "\n");
     88   return Result;
     89 }
     90 
     91 // Adds the just-emitted function to the symbol table.
     92 void OProfileJITEventListener::NotifyFunctionEmitted(
     93     const Function &F, void *FnStart, size_t FnSize,
     94     const JITEvent_EmittedFunctionDetails &Details) {
     95   assert(F.hasName() && FnStart != 0 && "Bad symbol to add");
     96   if (Wrapper.op_write_native_code(F.getName().data(),
     97                            reinterpret_cast<uint64_t>(FnStart),
     98                            FnStart, FnSize) == -1) {
     99     DEBUG(dbgs() << "Failed to tell OProfile about native function "
    100           << F.getName() << " at ["
    101           << FnStart << "-" << ((char*)FnStart + FnSize) << "]\n");
    102     return;
    103   }
    104 
    105   if (!Details.LineStarts.empty()) {
    106     // Now we convert the line number information from the address/DebugLoc
    107     // format in Details to the address/filename/lineno format that OProfile
    108     // expects.  Note that OProfile 0.9.4 has a bug that causes it to ignore
    109     // line numbers for addresses above 4G.
    110     FilenameCache Filenames;
    111     std::vector<debug_line_info> LineInfo;
    112     LineInfo.reserve(1 + Details.LineStarts.size());
    113 
    114     DebugLoc FirstLoc = Details.LineStarts[0].Loc;
    115     assert(!FirstLoc.isUnknown()
    116            && "LineStarts should not contain unknown DebugLocs");
    117     MDNode *FirstLocScope = FirstLoc.getScope(F.getContext());
    118     DISubprogram FunctionDI = getDISubprogram(FirstLocScope);
    119     if (FunctionDI.Verify()) {
    120       // If we have debug info for the function itself, use that as the line
    121       // number of the first several instructions.  Otherwise, after filling
    122       // LineInfo, we'll adjust the address of the first line number to point at
    123       // the start of the function.
    124       debug_line_info line_info;
    125       line_info.vma = reinterpret_cast<uintptr_t>(FnStart);
    126       line_info.lineno = FunctionDI.getLineNumber();
    127       line_info.filename = Filenames.getFilename(FirstLocScope);
    128       LineInfo.push_back(line_info);
    129     }
    130 
    131     for (std::vector<EmittedFunctionDetails::LineStart>::const_iterator
    132            I = Details.LineStarts.begin(), E = Details.LineStarts.end();
    133          I != E; ++I) {
    134       LineInfo.push_back(LineStartToOProfileFormat(
    135                            *Details.MF, Filenames, I->Address, I->Loc));
    136     }
    137 
    138     // In case the function didn't have line info of its own, adjust the first
    139     // line info's address to include the start of the function.
    140     LineInfo[0].vma = reinterpret_cast<uintptr_t>(FnStart);
    141 
    142     if (Wrapper.op_write_debug_line_info(FnStart, LineInfo.size(),
    143                                       &*LineInfo.begin()) == -1) {
    144       DEBUG(dbgs()
    145             << "Failed to tell OProfile about line numbers for native function "
    146             << F.getName() << " at ["
    147             << FnStart << "-" << ((char*)FnStart + FnSize) << "]\n");
    148     }
    149   }
    150 }
    151 
    152 // Removes the being-deleted function from the symbol table.
    153 void OProfileJITEventListener::NotifyFreeingMachineCode(void *FnStart) {
    154   assert(FnStart && "Invalid function pointer");
    155   if (Wrapper.op_unload_native_code(reinterpret_cast<uint64_t>(FnStart)) == -1) {
    156     DEBUG(dbgs()
    157           << "Failed to tell OProfile about unload of native function at "
    158           << FnStart << "\n");
    159   }
    160 }
    161 
    162 }  // anonymous namespace.
    163 
    164 namespace llvm {
    165 JITEventListener *JITEventListener::createOProfileJITEventListener() {
    166   static OwningPtr<OProfileWrapper> JITProfilingWrapper(new OProfileWrapper);
    167   return new OProfileJITEventListener(*JITProfilingWrapper);
    168 }
    169 
    170 // for testing
    171 JITEventListener *JITEventListener::createOProfileJITEventListener(
    172                                       OProfileWrapper* TestImpl) {
    173   return new OProfileJITEventListener(*TestImpl);
    174 }
    175 
    176 } // namespace llvm
    177 
    178