Enable lazy compilation in MCJIT

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161438 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/MCJIT/MCJIT.cpp

@@ -18,6 +18,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/DynamicLibrary.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/MutexGuard.h"
 #include "llvm/Target/TargetData.h"
 
 using namespace llvm;
@@ -54,9 +55,35 @@ ExecutionEngine *MCJIT::createJIT(Module *M,
 
 MCJIT::MCJIT(Module *m, TargetMachine *tm, TargetJITInfo &tji,
              RTDyldMemoryManager *MM, bool AllocateGVsWithCode)
-  : ExecutionEngine(m), TM(tm), MemMgr(MM), M(m), OS(Buffer), Dyld(MM) {
+  : ExecutionEngine(m), TM(tm), Ctx(0), MemMgr(MM), Dyld(MM), 
+    isCompiled(false), M(m), OS(Buffer)  {
 
   setTargetData(TM->getTargetData());
+}
+
+MCJIT::~MCJIT() {
+  delete MemMgr;
+  delete TM;
+}
+
+void MCJIT::emitObject(Module *m) {
+  /// Currently, MCJIT only supports a single module and the module passed to
+  /// this function call is expected to be the contained module.  The module
+  /// is passed as a parameter here to prepare for multiple module support in 
+  /// the future.
+  assert(M == m);
+
+  // Get a thread lock to make sure we aren't trying to compile multiple times
+  MutexGuard locked(lock);
+
+  // FIXME: Track compilation state on a per-module basis when multiple modules
+  //        are supported.
+  // Re-compilation is not supported
+  if (isCompiled)
+    return;
+
+  PassManager PM;
+
   PM.add(new TargetData(*TM->getTargetData()));
 
   // Turn the machine code intermediate representation into bytes in memory
@@ -69,23 +96,22 @@ MCJIT::MCJIT(Module *m, TargetMachine *tm, TargetJITInfo &tji,
   // FIXME: When we support multiple modules, we'll want to move the code
   // gen and finalization out of the constructor here and do it more
   // on-demand as part of getPointerToFunction().
-  PM.run(*M);
+  PM.run(*m);
   // Flush the output buffer so the SmallVector gets its data.
   OS.flush();
 
   // Load the object into the dynamic linker.
-  MemoryBuffer *MB = MemoryBuffer::getMemBuffer(StringRef(Buffer.data(),
+  MemoryBuffer* MB = MemoryBuffer::getMemBuffer(StringRef(Buffer.data(),
                                                           Buffer.size()),
                                                 "", false);
   if (Dyld.loadObject(MB))
     report_fatal_error(Dyld.getErrorString());
+
   // Resolve any relocations.
   Dyld.resolveRelocations();
-}
 
-MCJIT::~MCJIT() {
-  delete MemMgr;
-  delete TM;
+  // FIXME: Add support for per-module compilation state
+  isCompiled = true;
 }
 
 void *MCJIT::getPointerToBasicBlock(BasicBlock *BB) {
@@ -93,6 +119,10 @@ void *MCJIT::getPointerToBasicBlock(BasicBlock *BB) {
 }
 
 void *MCJIT::getPointerToFunction(Function *F) {
+  // FIXME: Add support for per-module compilation state
+  if (!isCompiled)
+    emitObject(M);
+
   if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
     bool AbortOnFailure = !F->hasExternalWeakLinkage();
     void *Addr = getPointerToNamedFunction(F->getName(), AbortOnFailure);
@@ -100,6 +130,7 @@ void *MCJIT::getPointerToFunction(Function *F) {
     return Addr;
   }
 
+  // FIXME: Should the Dyld be retaining module information? Probably not.
   // FIXME: Should we be using the mangler for this? Probably.
   StringRef BaseName = F->getName();
   if (BaseName[0] == '\1')
@@ -218,6 +249,10 @@ GenericValue MCJIT::runFunction(Function *F,
 
 void *MCJIT::getPointerToNamedFunction(const std::string &Name,
                                        bool AbortOnFailure) {
+  // FIXME: Add support for per-module compilation state
+  if (!isCompiled)
+    emitObject(M);
+
   if (!isSymbolSearchingDisabled() && MemMgr) {
     void *ptr = MemMgr->getPointerToNamedFunction(Name, false);
     if (ptr)

lib/ExecutionEngine/MCJIT/MCJIT.h

@@ -29,17 +29,16 @@ class MCJIT : public ExecutionEngine {
   TargetMachine *TM;
   MCContext *Ctx;
   RTDyldMemoryManager *MemMgr;
+  RuntimeDyld Dyld;
 
-  // FIXME: These may need moved to a separate 'jitstate' member like the
-  // non-MC JIT does for multithreading and such. Just keep them here for now.
-  PassManager PM;
+  // FIXME: Add support for multiple modules
+  bool isCompiled;
   Module *M;
-  // FIXME: This really doesn't belong here.
+
+  // FIXME: Move these to a single container which manages JITed objects
   SmallVector<char, 4096> Buffer; // Working buffer into which we JIT.
   raw_svector_ostream OS;
 
-  RuntimeDyld Dyld;
-
 public:
   ~MCJIT();
 
@@ -91,6 +90,14 @@ public:
                                     TargetMachine *TM);
 
   // @}
+
+protected:
+  /// emitObject -- Generate a JITed object in memory from the specified module
+  /// Currently, MCJIT only supports a single module and the module passed to
+  /// this function call is expected to be the contained module.  The module
+  /// is passed as a parameter here to prepare for multiple module support in 
+  /// the future.
+  void emitObject(Module *M);
 };
 
 } // End llvm namespace