[Orc] New JIT APIs.

This patch adds a new set of JIT APIs to LLVM. The aim of these new APIs is to
cleanly support a wider range of JIT use cases in LLVM, and encourage the
development and contribution of re-usable infrastructure for LLVM JIT use-cases.

These APIs are intended to live alongside the MCJIT APIs, and should not affect
existing clients.

Included in this patch:

1) New headers in include/llvm/ExecutionEngine/Orc that provide a set of
   components for building JIT infrastructure.
   Implementation code for these headers lives in lib/ExecutionEngine/Orc.

2) A prototype re-implementation of MCJIT (OrcMCJITReplacement) built out of the
   new components.

3) Minor changes to RTDyldMemoryManager needed to support the new components.
   These changes should not impact existing clients.

4) A new flag for lli, -use-orcmcjit, which will cause lli to use the
   OrcMCJITReplacement class as its underlying execution engine, rather than
   MCJIT itself.

Tests to follow shortly.

Special thanks to Michael Ilseman, Pete Cooper, David Blaikie, Eric Christopher,
Justin Bogner, and Jim Grosbach for extensive feedback and discussion.

llvm-svn: 226940

1 files changed, 112 insertions, 0 deletions

diff --git a/llvm/lib/ExecutionEngine/Orc/CloneSubModule.cpp b/llvm/lib/ExecutionEngine/Orc/CloneSubModule.cpp
new file mode 100644
index 00000000000..54acb78153e
--- /dev/null
+++ b/llvm/lib/ExecutionEngine/Orc/CloneSubModule.cpp
@@ -0,0 +1,112 @@
+#include "llvm/ExecutionEngine/Orc/CloneSubModule.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+
+using namespace llvm;
+
+void llvm::copyGVInitializer(GlobalVariable &New, const GlobalVariable &Orig,
+                             ValueToValueMapTy &VMap) {
+  if (Orig.hasInitializer())
+    New.setInitializer(MapValue(Orig.getInitializer(), VMap));
+}
+
+void llvm::copyFunctionBody(Function &New, const Function &Orig,
+                            ValueToValueMapTy &VMap) {
+  if (!Orig.isDeclaration()) {
+    Function::arg_iterator DestI = New.arg_begin();
+    for (Function::const_arg_iterator J = Orig.arg_begin(); J != Orig.arg_end();
+         ++J) {
+      DestI->setName(J->getName());
+      VMap[J] = DestI++;
+    }
+
+    SmallVector<ReturnInst *, 8> Returns; // Ignore returns cloned.
+    CloneFunctionInto(&New, &Orig, VMap, /*ModuleLevelChanges=*/true, Returns);
+  }
+}
+
+std::unique_ptr<Module>
+llvm::CloneSubModule(const Module &M,
+                     HandleGlobalVariableFtor HandleGlobalVariable,
+                     HandleFunctionFtor HandleFunction, bool KeepInlineAsm) {
+
+  ValueToValueMapTy VMap;
+
+  // First off, we need to create the new module.
+  std::unique_ptr<Module> New =
+      llvm::make_unique<Module>(M.getModuleIdentifier(), M.getContext());
+
+  New->setDataLayout(M.getDataLayout());
+  New->setTargetTriple(M.getTargetTriple());
+  if (KeepInlineAsm)
+    New->setModuleInlineAsm(M.getModuleInlineAsm());
+
+  // Copy global variables (but not initializers, yet).
+  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
+       I != E; ++I) {
+    GlobalVariable *GV = new GlobalVariable(
+        *New, I->getType()->getElementType(), I->isConstant(), I->getLinkage(),
+        (Constant *)nullptr, I->getName(), (GlobalVariable *)nullptr,
+        I->getThreadLocalMode(), I->getType()->getAddressSpace());
+    GV->copyAttributesFrom(I);
+    VMap[I] = GV;
+  }
+
+  // Loop over the functions in the module, making external functions as before
+  for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
+    Function *NF =
+        Function::Create(cast<FunctionType>(I->getType()->getElementType()),
+                         I->getLinkage(), I->getName(), &*New);
+    NF->copyAttributesFrom(I);
+    VMap[I] = NF;
+  }
+
+  // Loop over the aliases in the module
+  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
+       I != E; ++I) {
+    auto *PTy = cast<PointerType>(I->getType());
+    auto *GA =
+        GlobalAlias::create(PTy->getElementType(), PTy->getAddressSpace(),
+                            I->getLinkage(), I->getName(), &*New);
+    GA->copyAttributesFrom(I);
+    VMap[I] = GA;
+  }
+
+  // Now that all of the things that global variable initializer can refer to
+  // have been created, loop through and copy the global variable referrers
+  // over...  We also set the attributes on the global now.
+  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
+       I != E; ++I) {
+    GlobalVariable &GV = *cast<GlobalVariable>(VMap[I]);
+    HandleGlobalVariable(GV, *I, VMap);
+  }
+
+  // Similarly, copy over function bodies now...
+  //
+  for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
+    Function &F = *cast<Function>(VMap[I]);
+    HandleFunction(F, *I, VMap);
+  }
+
+  // And aliases
+  for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
+       I != E; ++I) {
+    GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
+    if (const Constant *C = I->getAliasee())
+      GA->setAliasee(MapValue(C, VMap));
+  }
+
+  // And named metadata....
+  for (Module::const_named_metadata_iterator I = M.named_metadata_begin(),
+                                             E = M.named_metadata_end();
+       I != E; ++I) {
+    const NamedMDNode &NMD = *I;
+    NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
+    for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
+      NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
+  }
+
+  return New;
+}