[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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226940 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 124 insertions, 0 deletions

diff --git a/lib/ExecutionEngine/Orc/OrcMCJITReplacement.cpp b/lib/ExecutionEngine/Orc/OrcMCJITReplacement.cpp
new file mode 100644
index 00000000000..f658ab2b298
--- /dev/null
+++ b/lib/ExecutionEngine/Orc/OrcMCJITReplacement.cpp
@@ -0,0 +1,124 @@
+//===-------- OrcMCJITReplacement.cpp - Orc-based MCJIT replacement -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "OrcMCJITReplacement.h"
+#include "llvm/ExecutionEngine/GenericValue.h"
+
+namespace {
+
+static struct RegisterJIT {
+  RegisterJIT() { llvm::OrcMCJITReplacement::Register(); }
+} JITRegistrator;
+
+extern "C" void LLVMLinkInOrcMCJITReplacement() {}
+}
+
+namespace llvm {
+
+GenericValue
+OrcMCJITReplacement::runFunction(Function *F,
+                                 const std::vector<GenericValue> &ArgValues) {
+  assert(F && "Function *F was null at entry to run()");
+
+  void *FPtr = getPointerToFunction(F);
+  assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
+  FunctionType *FTy = F->getFunctionType();
+  Type *RetTy = FTy->getReturnType();
+
+  assert((FTy->getNumParams() == ArgValues.size() ||
+          (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
+         "Wrong number of arguments passed into function!");
+  assert(FTy->getNumParams() == ArgValues.size() &&
+         "This doesn't support passing arguments through varargs (yet)!");
+
+  // Handle some common cases first.  These cases correspond to common `main'
+  // prototypes.
+  if (RetTy->isIntegerTy(32) || RetTy->isVoidTy()) {
+    switch (ArgValues.size()) {
+    case 3:
+      if (FTy->getParamType(0)->isIntegerTy(32) &&
+          FTy->getParamType(1)->isPointerTy() &&
+          FTy->getParamType(2)->isPointerTy()) {
+        int (*PF)(int, char **, const char **) =
+            (int (*)(int, char **, const char **))(intptr_t)FPtr;
+
+        // Call the function.
+        GenericValue rv;
+        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
+                                 (char **)GVTOP(ArgValues[1]),
+                                 (const char **)GVTOP(ArgValues[2])));
+        return rv;
+      }
+      break;
+    case 2:
+      if (FTy->getParamType(0)->isIntegerTy(32) &&
+          FTy->getParamType(1)->isPointerTy()) {
+        int (*PF)(int, char **) = (int (*)(int, char **))(intptr_t)FPtr;
+
+        // Call the function.
+        GenericValue rv;
+        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
+                                 (char **)GVTOP(ArgValues[1])));
+        return rv;
+      }
+      break;
+    case 1:
+      if (FTy->getNumParams() == 1 && FTy->getParamType(0)->isIntegerTy(32)) {
+        GenericValue rv;
+        int (*PF)(int) = (int (*)(int))(intptr_t)FPtr;
+        rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
+        return rv;
+      }
+      break;
+    }
+  }
+
+  // Handle cases where no arguments are passed first.
+  if (ArgValues.empty()) {
+    GenericValue rv;
+    switch (RetTy->getTypeID()) {
+    default:
+      llvm_unreachable("Unknown return type for function call!");
+    case Type::IntegerTyID: {
+      unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
+      if (BitWidth == 1)
+        rv.IntVal = APInt(BitWidth, ((bool (*)())(intptr_t)FPtr)());
+      else if (BitWidth <= 8)
+        rv.IntVal = APInt(BitWidth, ((char (*)())(intptr_t)FPtr)());
+      else if (BitWidth <= 16)
+        rv.IntVal = APInt(BitWidth, ((short (*)())(intptr_t)FPtr)());
+      else if (BitWidth <= 32)
+        rv.IntVal = APInt(BitWidth, ((int (*)())(intptr_t)FPtr)());
+      else if (BitWidth <= 64)
+        rv.IntVal = APInt(BitWidth, ((int64_t (*)())(intptr_t)FPtr)());
+      else
+        llvm_unreachable("Integer types > 64 bits not supported");
+      return rv;
+    }
+    case Type::VoidTyID:
+      rv.IntVal = APInt(32, ((int (*)())(intptr_t)FPtr)());
+      return rv;
+    case Type::FloatTyID:
+      rv.FloatVal = ((float (*)())(intptr_t)FPtr)();
+      return rv;
+    case Type::DoubleTyID:
+      rv.DoubleVal = ((double (*)())(intptr_t)FPtr)();
+      return rv;
+    case Type::X86_FP80TyID:
+    case Type::FP128TyID:
+    case Type::PPC_FP128TyID:
+      llvm_unreachable("long double not supported yet");
+    case Type::PointerTyID:
+      return PTOGV(((void *(*)())(intptr_t)FPtr)());
+    }
+  }
+
+  llvm_unreachable("Full-featured argument passing not supported yet!");
+}
+}