MCJIT.cpp revision fcbe5b71936b820647dffff0e4f9c60ece3988a5 
1//===-- MCJIT.cpp - MC-based Just-in-Time Compiler --------------------------===//
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 "MCJIT.h"
11#include "MCJITMemoryManager.h"
12#include "llvm/DerivedTypes.h"
13#include "llvm/Function.h"
14#include "llvm/ExecutionEngine/GenericValue.h"
15#include "llvm/ExecutionEngine/MCJIT.h"
16#include "llvm/ExecutionEngine/JITMemoryManager.h"
17#include "llvm/MC/MCAsmInfo.h"
18#include "llvm/Support/ErrorHandling.h"
19#include "llvm/Support/DynamicLibrary.h"
20#include "llvm/Support/MemoryBuffer.h"
21#include "llvm/Target/TargetData.h"
22
23using namespace llvm;
24
25namespace {
26
27static struct RegisterJIT {
28  RegisterJIT() { MCJIT::Register(); }
29} JITRegistrator;
30
31}
32
33extern "C" void LLVMLinkInMCJIT() {
34}
35
36ExecutionEngine *MCJIT::createJIT(Module *M,
37                                  std::string *ErrorStr,
38                                  JITMemoryManager *JMM,
39                                  CodeGenOpt::Level OptLevel,
40                                  bool GVsWithCode,
41                                  CodeModel::Model CMM,
42                                  StringRef MArch,
43                                  StringRef MCPU,
44                                  const SmallVectorImpl<std::string>& MAttrs) {
45  // Try to register the program as a source of symbols to resolve against.
46  //
47  // FIXME: Don't do this here.
48  sys::DynamicLibrary::LoadLibraryPermanently(0, NULL);
49
50  // Pick a target either via -march or by guessing the native arch.
51  //
52  // FIXME: This should be lifted out of here, it isn't something which should
53  // be part of the JIT policy, rather the burden for this selection should be
54  // pushed to clients.
55  TargetMachine *TM = MCJIT::selectTarget(M, MArch, MCPU, MAttrs, ErrorStr);
56  if (!TM || (ErrorStr && ErrorStr->length() > 0)) return 0;
57  TM->setCodeModel(CMM);
58
59  // If the target supports JIT code generation, create the JIT.
60  if (TargetJITInfo *TJ = TM->getJITInfo())
61    return new MCJIT(M, TM, *TJ, new MCJITMemoryManager(JMM), OptLevel,
62                     GVsWithCode);
63
64  if (ErrorStr)
65    *ErrorStr = "target does not support JIT code generation";
66  return 0;
67}
68
69MCJIT::MCJIT(Module *m, TargetMachine *tm, TargetJITInfo &tji,
70             RTDyldMemoryManager *MM, CodeGenOpt::Level OptLevel,
71             bool AllocateGVsWithCode)
72  : ExecutionEngine(m), TM(tm), MemMgr(MM), M(m), OS(Buffer), Dyld(MM) {
73
74  PM.add(new TargetData(*TM->getTargetData()));
75
76  // Turn the machine code intermediate representation into bytes in memory
77  // that may be executed.
78  if (TM->addPassesToEmitMC(PM, Ctx, OS, CodeGenOpt::Default, false)) {
79    report_fatal_error("Target does not support MC emission!");
80  }
81
82  // Initialize passes.
83  // FIXME: When we support multiple modules, we'll want to move the code
84  // gen and finalization out of the constructor here and do it more
85  // on-demand as part of getPointerToFunction().
86  PM.run(*M);
87  // Flush the output buffer so the SmallVector gets its data.
88  OS.flush();
89
90  // Load the object into the dynamic linker.
91  // FIXME: It would be nice to avoid making yet another copy.
92  MemoryBuffer *MB = MemoryBuffer::getMemBufferCopy(StringRef(Buffer.data(),
93                                                              Buffer.size()));
94  if (Dyld.loadObject(MB))
95    report_fatal_error(Dyld.getErrorString());
96}
97
98MCJIT::~MCJIT() {
99  delete MemMgr;
100}
101
102void *MCJIT::getPointerToBasicBlock(BasicBlock *BB) {
103  report_fatal_error("not yet implemented");
104  return 0;
105}
106
107void *MCJIT::getPointerToFunction(Function *F) {
108  if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
109    bool AbortOnFailure = !F->hasExternalWeakLinkage();
110    void *Addr = getPointerToNamedFunction(F->getName(), AbortOnFailure);
111    addGlobalMapping(F, Addr);
112    return Addr;
113  }
114
115  Twine Name = TM->getMCAsmInfo()->getGlobalPrefix() + F->getName();
116  return (void*)Dyld.getSymbolAddress(Name.str());
117}
118
119void *MCJIT::recompileAndRelinkFunction(Function *F) {
120  report_fatal_error("not yet implemented");
121}
122
123void MCJIT::freeMachineCodeForFunction(Function *F) {
124  report_fatal_error("not yet implemented");
125}
126
127GenericValue MCJIT::runFunction(Function *F,
128                                const std::vector<GenericValue> &ArgValues) {
129  assert(F && "Function *F was null at entry to run()");
130
131  void *FPtr = getPointerToFunction(F);
132  assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
133  const FunctionType *FTy = F->getFunctionType();
134  const Type *RetTy = FTy->getReturnType();
135
136  assert((FTy->getNumParams() == ArgValues.size() ||
137          (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
138         "Wrong number of arguments passed into function!");
139  assert(FTy->getNumParams() == ArgValues.size() &&
140         "This doesn't support passing arguments through varargs (yet)!");
141
142  // Handle some common cases first.  These cases correspond to common `main'
143  // prototypes.
144  if (RetTy->isIntegerTy(32) || RetTy->isVoidTy()) {
145    switch (ArgValues.size()) {
146    case 3:
147      if (FTy->getParamType(0)->isIntegerTy(32) &&
148          FTy->getParamType(1)->isPointerTy() &&
149          FTy->getParamType(2)->isPointerTy()) {
150        int (*PF)(int, char **, const char **) =
151          (int(*)(int, char **, const char **))(intptr_t)FPtr;
152
153        // Call the function.
154        GenericValue rv;
155        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
156                                 (char **)GVTOP(ArgValues[1]),
157                                 (const char **)GVTOP(ArgValues[2])));
158        return rv;
159      }
160      break;
161    case 2:
162      if (FTy->getParamType(0)->isIntegerTy(32) &&
163          FTy->getParamType(1)->isPointerTy()) {
164        int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
165
166        // Call the function.
167        GenericValue rv;
168        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
169                                 (char **)GVTOP(ArgValues[1])));
170        return rv;
171      }
172      break;
173    case 1:
174      if (FTy->getNumParams() == 1 &&
175          FTy->getParamType(0)->isIntegerTy(32)) {
176        GenericValue rv;
177        int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
178        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
179        return rv;
180      }
181      break;
182    }
183  }
184
185  // Handle cases where no arguments are passed first.
186  if (ArgValues.empty()) {
187    GenericValue rv;
188    switch (RetTy->getTypeID()) {
189    default: llvm_unreachable("Unknown return type for function call!");
190    case Type::IntegerTyID: {
191      unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
192      if (BitWidth == 1)
193        rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
194      else if (BitWidth <= 8)
195        rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
196      else if (BitWidth <= 16)
197        rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
198      else if (BitWidth <= 32)
199        rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
200      else if (BitWidth <= 64)
201        rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
202      else
203        llvm_unreachable("Integer types > 64 bits not supported");
204      return rv;
205    }
206    case Type::VoidTyID:
207      rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
208      return rv;
209    case Type::FloatTyID:
210      rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
211      return rv;
212    case Type::DoubleTyID:
213      rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
214      return rv;
215    case Type::X86_FP80TyID:
216    case Type::FP128TyID:
217    case Type::PPC_FP128TyID:
218      llvm_unreachable("long double not supported yet");
219      return rv;
220    case Type::PointerTyID:
221      return PTOGV(((void*(*)())(intptr_t)FPtr)());
222    }
223  }
224
225  assert("Full-featured argument passing not supported yet!");
226  return GenericValue();
227}
228