lib/ExecutionEngine/JIT/OProfileJITEventListener.cpp

   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 calls into OProfile to tell
  11 // it about JITted functions.  For now, we only record function names and sizes,
  12 // but eventually we'll also record line number information.
  13 //
  14 // See http://oprofile.sourceforge.net/doc/devel/jit-interface.html for the
  15 // definition of the interface we're using.
  16 //
  17 //===----------------------------------------------------------------------===//
  18
  19 #define DEBUG_TYPE "oprofile-jit-event-listener"
  20 #include "llvm/Function.h"
  21 #include "llvm/Metadata.h"
  22 #include "llvm/ADT/DenseMap.h"
  23 #include "llvm/Analysis/DebugInfo.h"
  24 #include "llvm/CodeGen/MachineFunction.h"
  25 #include "llvm/ExecutionEngine/JITEventListener.h"
  26 #include "llvm/Support/Debug.h"
  27 #include "llvm/Support/ValueHandle.h"
  28 #include "llvm/Support/raw_ostream.h"
  29 #include "llvm/System/Errno.h"
  30 #include "llvm/Config/config.h"
  31 #include <stddef.h>
  32 using namespace llvm;
  33
  34 #if USE_OPROFILE
  35
  36 #include <opagent.h>
  37
  38 namespace {
  39
  40 class OProfileJITEventListener : public JITEventListener {
  41   op_agent_t Agent;
  42 public:
  43   OProfileJITEventListener();
  44   ~OProfileJITEventListener();
  45
  46   virtual void NotifyFunctionEmitted(const Function &F,
  47                                      void *FnStart, size_t FnSize,
  48                                      const EmittedFunctionDetails &Details);
  49   virtual void NotifyFreeingMachineCode(void *OldPtr);
  50 };
  51
  52 OProfileJITEventListener::OProfileJITEventListener()
  53     : Agent(op_open_agent()) {
  54   if (Agent == NULL) {
  55     const std::string err_str = sys::StrError();
  56     DEBUG(dbgs() << "Failed to connect to OProfile agent: " << err_str << "\n");
  57   } else {
  58     DEBUG(dbgs() << "Connected to OProfile agent.\n");
  59   }
  60 }
  61
  62 OProfileJITEventListener::~OProfileJITEventListener() {
  63   if (Agent != NULL) {
  64     if (op_close_agent(Agent) == -1) {
  65       const std::string err_str = sys::StrError();
  66       DEBUG(dbgs() << "Failed to disconnect from OProfile agent: "
  67                    << err_str << "\n");
  68     } else {
  69       DEBUG(dbgs() << "Disconnected from OProfile agent.\n");
  70     }
  71   }
  72 }
  73
  74 class FilenameCache {
  75   // Holds the filename of each Scope, so that we can pass a null-terminated
  76   // string into oprofile.  Use an AssertingVH rather than a ValueMap because we
  77   // shouldn't be modifying any MDNodes while this map is alive.
  78   DenseMap<AssertingVH<MDNode>, std::string> Filenames;
  79
  80  public:
  81   const char *getFilename(MDNode *Scope) {
  82     std::string &Filename = Filenames[Scope];
  83     if (Filename.empty()) {
  84       Filename = DIScope(Scope).getFilename();
  85     }
  86     return Filename.c_str();
  87   }
  88 };
  89
  90 static debug_line_info LineStartToOProfileFormat(
  91     const MachineFunction &MF, FilenameCache &Filenames,
  92     uintptr_t Address, DebugLoc Loc) {
  93   debug_line_info Result;
  94   Result.vma = Address;
  95   Result.lineno = Loc.getLine();
  96   Result.filename = Filenames.getFilename(
  97     Loc.getScope(MF.getFunction()->getContext()));
  98   DEBUG(dbgs() << "Mapping " << reinterpret_cast<void*>(Result.vma) << " to "
  99                << Result.filename << ":" << Result.lineno << "\n");
 100   return Result;
 101 }
 102
 103 // Adds the just-emitted function to the symbol table.
 104 void OProfileJITEventListener::NotifyFunctionEmitted(
 105     const Function &F, void *FnStart, size_t FnSize,
 106     const EmittedFunctionDetails &Details) {
 107   assert(F.hasName() && FnStart != 0 && "Bad symbol to add");
 108   if (op_write_native_code(Agent, F.getName().data(),
 109                            reinterpret_cast<uint64_t>(FnStart),
 110                            FnStart, FnSize) == -1) {
 111     DEBUG(dbgs() << "Failed to tell OProfile about native function "
 112           << F.getName() << " at ["
 113           << FnStart << "-" << ((char*)FnStart + FnSize) << "]\n");
 114     return;
 115   }
 116
 117   if (!Details.LineStarts.empty()) {
 118     // Now we convert the line number information from the address/DebugLoc
 119     // format in Details to the address/filename/lineno format that OProfile
 120     // expects.  Note that OProfile 0.9.4 has a bug that causes it to ignore
 121     // line numbers for addresses above 4G.
 122     FilenameCache Filenames;
 123     std::vector<debug_line_info> LineInfo;
 124     LineInfo.reserve(1 + Details.LineStarts.size());
 125
 126     DebugLoc FirstLoc = Details.LineStarts[0].Loc;
 127     assert(!FirstLoc.isUnknown()
 128            && "LineStarts should not contain unknown DebugLocs");
 129     MDNode *FirstLocScope = FirstLoc.getScope(F.getContext());
 130     DISubprogram FunctionDI = getDISubprogram(FirstLocScope);
 131     if (FunctionDI.Verify()) {
 132       // If we have debug info for the function itself, use that as the line
 133       // number of the first several instructions.  Otherwise, after filling
 134       // LineInfo, we'll adjust the address of the first line number to point at
 135       // the start of the function.
 136       debug_line_info line_info;
 137       line_info.vma = reinterpret_cast<uintptr_t>(FnStart);
 138       line_info.lineno = FunctionDI.getLineNumber();
 139       line_info.filename = Filenames.getFilename(FirstLocScope);
 140       LineInfo.push_back(line_info);
 141     }
 142
 143     for (std::vector<EmittedFunctionDetails::LineStart>::const_iterator
 144            I = Details.LineStarts.begin(), E = Details.LineStarts.end();
 145          I != E; ++I) {
 146       LineInfo.push_back(LineStartToOProfileFormat(
 147                            *Details.MF, Filenames, I->Address, I->Loc));
 148     }
 149
 150     // In case the function didn't have line info of its own, adjust the first
 151     // line info's address to include the start of the function.
 152     LineInfo[0].vma = reinterpret_cast<uintptr_t>(FnStart);
 153
 154     if (op_write_debug_line_info(Agent, FnStart,
 155                                  LineInfo.size(), &*LineInfo.begin()) == -1) {
 156       DEBUG(dbgs()
 157             << "Failed to tell OProfile about line numbers for native function "
 158             << F.getName() << " at ["
 159             << FnStart << "-" << ((char*)FnStart + FnSize) << "]\n");
 160     }
 161   }
 162 }
 163
 164 // Removes the being-deleted function from the symbol table.
 165 void OProfileJITEventListener::NotifyFreeingMachineCode(void *FnStart) {
 166   assert(FnStart && "Invalid function pointer");
 167   if (op_unload_native_code(Agent, reinterpret_cast<uint64_t>(FnStart)) == -1) {
 168     DEBUG(dbgs()
 169           << "Failed to tell OProfile about unload of native function at "
 170           << FnStart << "\n");
 171   }
 172 }
 173
 174 }  // anonymous namespace.
 175
 176 namespace llvm {
 177 JITEventListener *createOProfileJITEventListener() {
 178   return new OProfileJITEventListener;
 179 }
 180 }
 181
 182 #else  // USE_OPROFILE
 183
 184 namespace llvm {
 185 // By defining this to return NULL, we can let clients call it unconditionally,
 186 // even if they haven't configured with the OProfile libraries.
 187 JITEventListener *createOProfileJITEventListener() {
 188   return NULL;
 189 }
 190 }  // namespace llvm
 191
 192 #endif  // USE_OPROFILE