MCJIT: Add faux remote target execution to lli for the MCJIT.

Simulate a remote target address space by allocating a seperate chunk of
memory for the target and re-mapping section addresses to that prior to
execution. Later we'll want to have a truly remote process, but for now
this gets us closer to being able to test the remote target
functionality outside LLDB.

rdar://12157052

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163216 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 171 insertions, 29 deletions

diff --git a/tools/lli/lli.cpp b/tools/lli/lli.cpp
index 3a3f4c7cdd..4004b6c4d4 100644
--- a/tools/lli/lli.cpp
+++ b/tools/lli/lli.cpp
@@ -13,6 +13,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#define DEBUG_TYPE "lli"
+#include "RecordingMemoryManager.h"
+#include "RemoteTarget.h"
 #include "llvm/LLVMContext.h"
 #include "llvm/Module.h"
 #include "llvm/Type.h"
@@ -32,9 +35,11 @@
 #include "llvm/Support/PluginLoader.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Format.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/DynamicLibrary.h"
 #include "llvm/Support/Memory.h"
 #include <cerrno>
@@ -73,6 +78,13 @@ namespace {
     "use-mcjit", cl::desc("Enable use of the MC-based JIT (if available)"),
     cl::init(false));
 
+  // The MCJIT supports building for a target address space separate from
+  // the JIT compilation process. Use a forked process and a copying
+  // memory manager with IPC to execute using this functionality.
+  cl::opt<bool> RemoteMCJIT("remote-mcjit",
+    cl::desc("Execute MCJIT'ed code in a separate process."),
+    cl::init(false));
+
   // Determine optimization level.
   cl::opt<char>
   OptLevel("O",
@@ -372,6 +384,79 @@ LLIMCJITMemoryManager::~LLIMCJITMemoryManager() {
     free(AllocatedDataMem[i].base());
 }
 
+
+void layoutRemoteTargetMemory(RemoteTarget *T, RecordingMemoryManager *JMM) {
+  // Lay out our sections in order, with all the code sections first, then
+  // all the data sections.
+  uint64_t CurOffset = 0;
+  unsigned MaxAlign = T->getPageAlignment();
+  SmallVector<std::pair<const void*, uint64_t>, 16> Offsets;
+  SmallVector<unsigned, 16> Sizes;
+  for (RecordingMemoryManager::const_code_iterator I = JMM->code_begin(),
+                                                   E = JMM->code_end();
+       I != E; ++I) {
+    DEBUG(dbgs() << "code region: size " << I->first.size()
+                 << ", alignment " << I->second << "\n");
+    // Align the current offset up to whatever is needed for the next
+    // section.
+    unsigned Align = I->second;
+    CurOffset = (CurOffset + Align - 1) / Align * Align;
+    // Save off the address of the new section and allocate its space.
+    Offsets.push_back(std::pair<const void*,uint64_t>(I->first.base(), CurOffset));
+    Sizes.push_back(I->first.size());
+    CurOffset += I->first.size();
+  }
+  // Adjust to keep code and data aligned on seperate pages.
+  CurOffset = (CurOffset + MaxAlign - 1) / MaxAlign * MaxAlign;
+  unsigned FirstDataIndex = Offsets.size();
+  for (RecordingMemoryManager::const_data_iterator I = JMM->data_begin(),
+                                                   E = JMM->data_end();
+       I != E; ++I) {
+    DEBUG(dbgs() << "data region: size " << I->first.size()
+                 << ", alignment " << I->second << "\n");
+    // Align the current offset up to whatever is needed for the next
+    // section.
+    unsigned Align = I->second;
+    CurOffset = (CurOffset + Align - 1) / Align * Align;
+    // Save off the address of the new section and allocate its space.
+    Offsets.push_back(std::pair<const void*,uint64_t>(I->first.base(), CurOffset));
+    Sizes.push_back(I->first.size());
+    CurOffset += I->first.size();
+  }
+
+  // Allocate space in the remote target.
+  uint64_t RemoteAddr;
+  if (T->allocateSpace(CurOffset, MaxAlign, RemoteAddr))
+    report_fatal_error(T->getErrorMsg());
+  // Map the section addresses so relocations will get updated in the local
+  // copies of the sections.
+  for (unsigned i = 0, e = Offsets.size(); i != e; ++i) {
+    uint64_t Addr = RemoteAddr + Offsets[i].second;
+    EE->mapSectionAddress(const_cast<void*>(Offsets[i].first), Addr);
+
+    DEBUG(dbgs() << "  Mapping local: " << Offsets[i].first
+                 << " to remote: " << format("%#018x", Addr) << "\n");
+
+  }
+  // Now load it all to the target.
+  for (unsigned i = 0, e = Offsets.size(); i != e; ++i) {
+    uint64_t Addr = RemoteAddr + Offsets[i].second;
+
+    if (i < FirstDataIndex) {
+      T->loadCode(Addr, Offsets[i].first, Sizes[i]);
+
+      DEBUG(dbgs() << "  loading code: " << Offsets[i].first
+            << " to remote: " << format("%#018x", Addr) << "\n");
+    } else {
+      T->loadData(Addr, Offsets[i].first, Sizes[i]);
+
+      DEBUG(dbgs() << "  loading data: " << Offsets[i].first
+            << " to remote: " << format("%#018x", Addr) << "\n");
+    }
+
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // main Driver function
 //
@@ -428,12 +513,19 @@ int main(int argc, char **argv, char * const *envp) {
     Mod->setTargetTriple(Triple::normalize(TargetTriple));
 
   // Enable MCJIT if desired.
-  LLIMCJITMemoryManager *JMM = 0;
+  JITMemoryManager *JMM = 0;
   if (UseMCJIT && !ForceInterpreter) {
     builder.setUseMCJIT(true);
-    JMM = new LLIMCJITMemoryManager();
+    if (RemoteMCJIT)
+      JMM = new RecordingMemoryManager();
+    else
+      JMM = new LLIMCJITMemoryManager();
     builder.setJITMemoryManager(JMM);
   } else {
+    if (RemoteMCJIT) {
+      errs() << "error: Remote process execution requires -use-mcjit\n";
+      exit(1);
+    }
     builder.setJITMemoryManager(ForceInterpreter ? 0 :
                                 JITMemoryManager::CreateDefaultMemManager());
   }
@@ -451,11 +543,14 @@ int main(int argc, char **argv, char * const *envp) {
   }
   builder.setOptLevel(OLvl);
 
-  TargetOptions Options;
-  Options.JITExceptionHandling = EnableJITExceptionHandling;
-  Options.JITEmitDebugInfo = EmitJitDebugInfo;
-  Options.JITEmitDebugInfoToDisk = EmitJitDebugInfoToDisk;
-  builder.setTargetOptions(Options);
+  // Remote target execution doesn't handle EH or debug registration.
+  if (!RemoteMCJIT) {
+    TargetOptions Options;
+    Options.JITExceptionHandling = EnableJITExceptionHandling;
+    Options.JITEmitDebugInfo = EmitJitDebugInfo;
+    Options.JITEmitDebugInfoToDisk = EmitJitDebugInfoToDisk;
+    builder.setTargetOptions(Options);
+  }
 
   EE = builder.create();
   if (!EE) {
@@ -473,6 +568,10 @@ int main(int argc, char **argv, char * const *envp) {
   EE->RegisterJITEventListener(
                 JITEventListener::createIntelJITEventListener());
 
+  if (!NoLazyCompilation && RemoteMCJIT) {
+    errs() << "warning: remote mcjit does not support lazy compilation\n";
+    NoLazyCompilation = true;
+  }
   EE->DisableLazyCompilation(NoLazyCompilation);
 
   // If the user specifically requested an argv[0] to pass into the program,
@@ -509,8 +608,13 @@ int main(int argc, char **argv, char * const *envp) {
   // Reset errno to zero on entry to main.
   errno = 0;
 
+  // Remote target MCJIT doesn't (yet) support static constructors. No reason
+  // it couldn't. This is a limitation of the LLI implemantation, not the
+  // MCJIT itself. FIXME.
+  //
   // Run static constructors.
-  EE->runStaticConstructorsDestructors(false);
+  if (!RemoteMCJIT)
+    EE->runStaticConstructorsDestructors(false);
 
   if (NoLazyCompilation) {
     for (Module::iterator I = Mod->begin(), E = Mod->end(); I != E; ++I) {
@@ -520,28 +624,66 @@ int main(int argc, char **argv, char * const *envp) {
     }
   }
 
-  // Clear instruction cache before code will be executed.
-  if (JMM)
-    JMM->invalidateInstructionCache();
-
-  // Run main.
-  int Result = EE->runFunctionAsMain(EntryFn, InputArgv, envp);
+  int Result;
+  if (RemoteMCJIT) {
+    RecordingMemoryManager *MM = static_cast<RecordingMemoryManager*>(JMM);
+    // Everything is prepared now, so lay out our program for the target
+    // address space, assign the section addresses to resolve any relocations,
+    // and send it to the target.
+    RemoteTarget Target;
+    Target.create();
+
+    // Ask for a pointer to the entry function. This triggers the actual
+    // compilation.
+    (void)EE->getPointerToFunction(EntryFn);
+
+    // Enough has been compiled to execute the entry function now, so
+    // layout the target memory.
+    layoutRemoteTargetMemory(&Target, MM);
+
+    // Since we're executing in a (at least simulated) remote address space,
+    // we can't use the ExecutionEngine::runFunctionAsMain(). We have to
+    // grab the function address directly here and tell the remote target
+    // to execute the function.
+    // FIXME: argv and envp handling.
+    uint64_t Entry = (uint64_t)EE->getPointerToFunction(EntryFn);
+
+    DEBUG(dbgs() << "Executing '" << EntryFn->getName() << "' at "
+                 << format("%#18x", Entry) << "\n");
+
+    if (Target.executeCode(Entry, Result))
+      errs() << "ERROR: " << Target.getErrorMsg() << "\n";
+
+    Target.stop();
+  } else {
+    // Clear instruction cache before code will be executed.
+    if (JMM)
+      static_cast<LLIMCJITMemoryManager*>(JMM)->invalidateInstructionCache();
 
-  // Run static destructors.
-  EE->runStaticConstructorsDestructors(true);
+    // Run main.
+    Result = EE->runFunctionAsMain(EntryFn, InputArgv, envp);
+  }
 
-  // If the program didn't call exit explicitly, we should call it now.
-  // This ensures that any atexit handlers get called correctly.
-  if (Function *ExitF = dyn_cast<Function>(Exit)) {
-    std::vector<GenericValue> Args;
-    GenericValue ResultGV;
-    ResultGV.IntVal = APInt(32, Result);
-    Args.push_back(ResultGV);
-    EE->runFunction(ExitF, Args);
-    errs() << "ERROR: exit(" << Result << ") returned!\n";
-    abort();
-  } else {
-    errs() << "ERROR: exit defined with wrong prototype!\n";
-    abort();
+  // Like static constructors, the remote target MCJIT support doesn't handle
+  // this yet. It could. FIXME.
+  if (!RemoteMCJIT) {
+    // Run static destructors.
+    EE->runStaticConstructorsDestructors(true);
+
+    // If the program didn't call exit explicitly, we should call it now.
+    // This ensures that any atexit handlers get called correctly.
+    if (Function *ExitF = dyn_cast<Function>(Exit)) {
+      std::vector<GenericValue> Args;
+      GenericValue ResultGV;
+      ResultGV.IntVal = APInt(32, Result);
+      Args.push_back(ResultGV);
+      EE->runFunction(ExitF, Args);
+      errs() << "ERROR: exit(" << Result << ") returned!\n";
+      abort();
+    } else {
+      errs() << "ERROR: exit defined with wrong prototype!\n";
+      abort();
+    }
   }
+  return Result;
 }