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/Analysis/DebugInfo.h"
  22 #include "llvm/CodeGen/MachineFunction.h"
  23 #include "llvm/ExecutionEngine/JITEventListener.h"
  24 #include "llvm/Support/Debug.h"
  25 #include "llvm/Support/raw_ostream.h"
  26 #include "llvm/System/Errno.h"
  27 #include "llvm/Config/config.h"
  28 #include <stddef.h>
  29 using namespace llvm;
  30
  31 #if USE_OPROFILE
  32
  33 #include <opagent.h>
  34
  35 namespace {
  36
  37 class OProfileJITEventListener : public JITEventListener {
  38   op_agent_t Agent;
  39 public:
  40   OProfileJITEventListener();
  41   ~OProfileJITEventListener();
  42
  43   virtual void NotifyFunctionEmitted(const Function &F,
  44                                      void *FnStart, size_t FnSize,
  45                                      const EmittedFunctionDetails &Details);
  46   virtual void NotifyFreeingMachineCode(const Function &F, void *OldPtr);
  47 };
  48
  49 OProfileJITEventListener::OProfileJITEventListener()
  50     : Agent(op_open_agent()) {
  51   if (Agent == NULL) {
  52     const std::string err_str = sys::StrError();
  53     DEBUG(errs() << "Failed to connect to OProfile agent: " << err_str << "\n");
  54   } else {
  55     DEBUG(errs() << "Connected to OProfile agent.\n");
  56   }
  57 }
  58
  59 OProfileJITEventListener::~OProfileJITEventListener() {
  60   if (Agent != NULL) {
  61     if (op_close_agent(Agent) == -1) {
  62       const std::string err_str = sys::StrError();
  63       DEBUG(errs() << "Failed to disconnect from OProfile agent: "
  64                    << err_str << "\n");
  65     } else {
  66       DEBUG(errs() << "Disconnected from OProfile agent.\n");
  67     }
  68   }
  69 }
  70
  71 class FilenameCache {
  72   // Holds the filename of each CompileUnit, so that we can pass the
  73   // pointer into oprofile.  These char*s are freed in the destructor.
  74   DenseMap<MDNode*, char*> Filenames;
  75   // Used as the scratch space in DICompileUnit::getFilename().
  76   std::string TempFilename;
  77
  78  public:
  79   const char* getFilename(MDNode *CompileUnit) {
  80     char *&Filename = Filenames[CompileUnit];
  81     if (Filename == NULL) {
  82       DICompileUnit CU(CompileUnit);
  83       Filename = strdup(CU.getFilename(TempFilename).c_str());
  84     }
  85     return Filename;
  86   }
  87   ~FilenameCache() {
  88     for (DenseMap<MDNode*, char*>::iterator
  89              I = Filenames.begin(), E = Filenames.end(); I != E;++I) {
  90       free(I->second);
  91     }
  92   }
  93 };
  94
  95 static debug_line_info LineStartToOProfileFormat(
  96     const MachineFunction &MF, FilenameCache &Filenames,
  97     uintptr_t Address, DebugLoc Loc) {
  98   debug_line_info Result;
  99   Result.vma = Address;
 100   const DebugLocTuple& tuple = MF.getDebugLocTuple(Loc);
 101   Result.lineno = tuple.Line;
 102   Result.filename = Filenames.getFilename(tuple.CompileUnit);
 103   DEBUG(errs() << "Mapping " << reinterpret_cast<void*>(Result.vma) << " to "
 104                << Result.filename << ":" << Result.lineno << "\n");
 105   return Result;
 106 }
 107
 108 // Adds the just-emitted function to the symbol table.
 109 void OProfileJITEventListener::NotifyFunctionEmitted(
 110     const Function &F, void *FnStart, size_t FnSize,
 111     const EmittedFunctionDetails &Details) {
 112   assert(F.hasName() && FnStart != 0 && "Bad symbol to add");
 113   if (op_write_native_code(Agent, F.getName().data(),
 114                            reinterpret_cast<uint64_t>(FnStart),
 115                            FnStart, FnSize) == -1) {
 116     DEBUG(errs() << "Failed to tell OProfile about native function "
 117           << F.getName() << " at ["
 118           << FnStart << "-" << ((char*)FnStart + FnSize) << "]\n");
 119     return;
 120   }
 121
 122   // Now we convert the line number information from the address/DebugLoc format
 123   // in Details to the address/filename/lineno format that OProfile expects.
 124   // OProfile 0.9.4 (and maybe later versions) has a bug that causes it to
 125   // ignore line numbers for addresses above 4G.
 126   FilenameCache Filenames;
 127   std::vector<debug_line_info> LineInfo;
 128   LineInfo.reserve(1 + Details.LineStarts.size());
 129   if (!Details.MF->getDefaultDebugLoc().isUnknown()) {
 130     LineInfo.push_back(LineStartToOProfileFormat(
 131         *Details.MF, Filenames,
 132         reinterpret_cast<uintptr_t>(FnStart),
 133         Details.MF->getDefaultDebugLoc()));
 134   }
 135   for (std::vector<EmittedFunctionDetails::LineStart>::const_iterator
 136            I = Details.LineStarts.begin(), E = Details.LineStarts.end();
 137        I != E; ++I) {
 138     LineInfo.push_back(LineStartToOProfileFormat(
 139         *Details.MF, Filenames, I->Address, I->Loc));
 140   }
 141   if (!LineInfo.empty()) {
 142     if (op_write_debug_line_info(Agent, FnStart,
 143                                  LineInfo.size(), &*LineInfo.begin()) == -1) {
 144       DEBUG(errs()
 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 to-be-deleted function from the symbol table.
 153 void OProfileJITEventListener::NotifyFreeingMachineCode(
 154     const Function &F, void *FnStart) {
 155   assert(FnStart && "Invalid function pointer");
 156   if (op_unload_native_code(Agent, reinterpret_cast<uint64_t>(FnStart)) == -1) {
 157     DEBUG(errs() << "Failed to tell OProfile about unload of native function "
 158                  << F.getName() << " at " << FnStart << "\n");
 159   }
 160 }
 161
 162 }  // anonymous namespace.
 163
 164 namespace llvm {
 165 JITEventListener *createOProfileJITEventListener() {
 166   return new OProfileJITEventListener;
 167 }
 168 }
 169
 170 #else  // USE_OPROFILE
 171
 172 namespace llvm {
 173 // By defining this to return NULL, we can let clients call it unconditionally,
 174 // even if they haven't configured with the OProfile libraries.
 175 JITEventListener *createOProfileJITEventListener() {
 176   return NULL;
 177 }
 178 }  // namespace llvm
 179
 180 #endif  // USE_OPROFILE