[ORC] Add custom IR compiler configuration to LLJITBuilder to enable obj caches.

LLJITBuilder now has a setCompileFunctionCreator method which can be used to
construct a CompileFunction for the LLJIT instance being created. The motivating
use-case for this is supporting ObjectCaches, which can now be set up at
compile-function construction time. To demonstrate this an example project,
LLJITWithObjectCache, is included.

llvm-svn: 365671

1 files changed, 95 insertions, 0 deletions

diff --git a/llvm/examples/LLJITExamples/LLJITWithObjectCache/LLJITWithObjectCache.cpp b/llvm/examples/LLJITExamples/LLJITWithObjectCache/LLJITWithObjectCache.cpp
new file mode 100644
index 00000000000..377babb8c3c
--- /dev/null
+++ b/llvm/examples/LLJITExamples/LLJITWithObjectCache/LLJITWithObjectCache.cpp
@@ -0,0 +1,95 @@
+//===--- LLJITWithObjectCache.cpp - An LLJIT example with an ObjectCache --===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ExecutionEngine/ObjectCache.h"
+#include "llvm/ExecutionEngine/Orc/LLJIT.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/InitLLVM.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include "../ExampleModules.h"
+
+using namespace llvm;
+using namespace llvm::orc;
+
+ExitOnError ExitOnErr;
+
+class MyObjectCache : public ObjectCache {
+public:
+  void notifyObjectCompiled(const Module *M,
+                            MemoryBufferRef ObjBuffer) override {
+    CachedObjects[M->getModuleIdentifier()] = MemoryBuffer::getMemBufferCopy(
+        ObjBuffer.getBuffer(), ObjBuffer.getBufferIdentifier());
+  }
+
+  std::unique_ptr<MemoryBuffer> getObject(const Module *M) override {
+    auto I = CachedObjects.find(M->getModuleIdentifier());
+    if (I == CachedObjects.end()) {
+      dbgs() << "No object for " << M->getModuleIdentifier()
+             << " in cache. Compiling.\n";
+      return nullptr;
+    }
+
+    dbgs() << "Object for " << M->getModuleIdentifier()
+           << " loaded from cache.\n";
+    return MemoryBuffer::getMemBuffer(I->second->getMemBufferRef());
+  }
+
+private:
+  StringMap<std::unique_ptr<MemoryBuffer>> CachedObjects;
+};
+
+void runJITWithCache(ObjectCache &ObjCache) {
+
+  // Create an LLJIT instance with a custom CompileFunction.
+  auto J = ExitOnErr(
+      LLJITBuilder()
+          .setCompileFunctionCreator(
+              [&](JITTargetMachineBuilder JTMB)
+                  -> Expected<IRCompileLayer::CompileFunction> {
+                auto TM = JTMB.createTargetMachine();
+                if (!TM)
+                  return TM.takeError();
+                return IRCompileLayer::CompileFunction(
+                    TMOwningSimpleCompiler(std::move(*TM), &ObjCache));
+              })
+          .create());
+
+  auto M = ExitOnErr(parseExampleModule(Add1Example, "add1"));
+
+  ExitOnErr(J->addIRModule(std::move(M)));
+
+  // Look up the JIT'd function, cast it to a function pointer, then call it.
+  auto Add1Sym = ExitOnErr(J->lookup("add1"));
+  int (*Add1)(int) = (int (*)(int))Add1Sym.getAddress();
+
+  int Result = Add1(42);
+  outs() << "add1(42) = " << Result << "\n";
+}
+
+int main(int argc, char *argv[]) {
+  // Initialize LLVM.
+  InitLLVM X(argc, argv);
+
+  InitializeNativeTarget();
+  InitializeNativeTargetAsmPrinter();
+
+  cl::ParseCommandLineOptions(argc, argv, "HowToUseLLJIT");
+  ExitOnErr.setBanner(std::string(argv[0]) + ": ");
+
+  MyObjectCache MyCache;
+
+  runJITWithCache(MyCache);
+  runJITWithCache(MyCache);
+
+  return 0;
+}