[CODEGEN/LLVM] Initial support for codegen LLVM. (#49)

* [LLVM] Initial support for codegen LLVM.

* Fix the naming issue of codegen

HalideIR @ 1a11a6c2

-Subproject commit e68ae61cd541ac29efc9fafe2ad061479bcaa9c9
+Subproject commit 1a11a6c2522b1d11a5ccdb9b4fe3976cbe7f9f27

Makefile

 ifndef config
 ifneq ("$(wildcard ./config.mk)","")
-	config = config.mk
+	config ?= config.mk
 else
-	config = make/config.mk
+	config ?= make/config.mk
 endif
 endif
 
@@ -19,24 +19,16 @@ SRC = $(wildcard src/*.cc src/*/*.cc src/*/*/*.cc)
 ALL_OBJ = $(patsubst src/%.cc, build/%.o, $(SRC))
 ALL_DEP = $(ALL_OBJ) $(LIB_HALIDE_IR)
 
-ifneq ($(USE_CUDA_PATH), NONE)
-	NVCC=$(USE_CUDA_PATH)/bin/nvcc
-endif
-
 export LDFLAGS = -pthread -lm
-export CFLAGS =  -std=c++11 -Wall -O2\
-	 -Iinclude -Idmlc-core/include -IHalideIR/src  -fPIC
-export FRAMEWORKS=
-
-ifneq ($(ADD_CFLAGS), NONE)
-	CFLAGS += $(ADD_CFLAGS)
-endif
+export CFLAGS =  -std=c++11 -Wall -O2 -fno-rtti\
+	 -Iinclude -Idmlc-core/include -IHalideIR/src  -fPIC -DDMLC_ENABLE_RTTI=0
 
-ifneq ($(ADD_LDFLAGS), NONE)
-	LDFLAGS += $(ADD_LDFLAGS)
+ifdef CUDA_PATH
+	NVCC=$(CUDA_PATH)/bin/nvcc
+	CFLAGS += -I$(CUDA_PATH)/include
+	LDFLAGS += -L$(CUDA_PATH)/lib64
 endif
 
-
 ifeq ($(USE_CUDA), 1)
 	CFLAGS += -DTVM_CUDA_RUNTIME=1
 	LDFLAGS += -lcuda -lcudart -lnvrtc
@@ -44,6 +36,7 @@ else
 	CFLAGS += -DTVM_CUDA_RUNTIME=0
 endif
 
+FRAMEWORKS=
 
 ifeq ($(USE_OPENCL), 1)
 	CFLAGS += -DTVM_OPENCL_RUNTIME=1
@@ -57,6 +50,23 @@ else
 	CFLAGS += -DTVM_OPENCL_RUNTIME=0
 endif
 
+# llvm configuration
+LLVM_CONFIG=llvm-config
+
+ifeq ($(USE_LLVM), 1)
+	LLVM_VERSION=$(shell $(LLVM_CONFIG) --version| cut -b 1,3)
+	LLVM_INCLUDE=$(filter -I%, $(shell $(LLVM_CONFIG) --cxxflags))
+	LDFLAGS += $(shell $(LLVM_CONFIG) --ldflags --libs --system-libs)
+	CFLAGS += $(LLVM_INCLUDE) -DTVM_LLVM_VERSION=$(LLVM_VERSION)
+endif
+
+ifdef $(ADD_CFLAGS)
+	CFLAGS += $(ADD_CFLAGS)
+endif
+
+ifdef $(ADD_LDFLAGS)
+	LDFLAGS += $(ADD_LDFLAGS)
+endif
 
 include tests/cpp/unittest.mk
 

dmlc-core @ 8dd36563

-Subproject commit 3a51614d39b69fdb5de1efcf1016426626d267a6
+Subproject commit 8dd365636528175e785448cf8a9f4e494c8ee0e0

include/tvm/buffer.h

@@ -90,7 +90,7 @@ class BufferNode : public Node {
                      Type dtype);
 
   static constexpr const char* _type_key = "Buffer";
-  TVM_DECLARE_NODE_TYPE_INFO(BufferNode);
+  TVM_DECLARE_NODE_TYPE_INFO(BufferNode, Node);
 };
 
 inline const BufferNode* Buffer::operator->() const {

include/tvm/codegen.h

@@ -32,6 +32,13 @@ PackedFunc BuildStackVM(
     const std::unordered_map<LoweredFunc, PackedFunc>& device_funcs);
 
 /*!
+ * \brief Build a LLVM VM function, this is still beta
+ * \param func The LoweredFunc to be build
+ * \return A packed function representing the func.
+ */
+PackedFunc BuildLLVM(LoweredFunc func);
+
+/*!
  * \brief Build a CUDA function with NVRTC
  *
  * \param fsplits The LoweredFuncs to be build (after SplitHostDevice)

include/tvm/expr.h

@@ -36,7 +36,6 @@ using Halide::Internal::make_zero;
 using Halide::Internal::as_const_int;
 using Halide::Internal::as_const_uint;
 
-
 inline Type TVMType2Type(TVMType t) {
   return Type(static_cast<halide_type_code_t>(t.code), t.bits, t.lanes);
 }
@@ -182,7 +181,7 @@ class IterVarNode : public Node {
   static IterVar make(Range dom, Var var, std::string thread_tag);
 
   static constexpr const char* _type_key = "IterVar";
-  TVM_DECLARE_NODE_TYPE_INFO(IterVarNode);
+  TVM_DECLARE_NODE_TYPE_INFO(IterVarNode, Node);
 };
 
 // inline implementations

include/tvm/ir.h

@@ -200,6 +200,8 @@ using Halide::Internal::Realize;
 using Halide::Internal::Block;
 using Halide::Internal::IfThenElse;
 using Halide::Internal::Evaluate;
+// ir functions
+using Halide::Internal::is_const_power_of_two_integer;
 
 }  // namespace ir
 }  // namespace tvm

include/tvm/lowered_func.h

@@ -92,7 +92,7 @@ class LoweredFuncNode : public FunctionBaseNode {
   }
 
   static constexpr const char* _type_key = "LoweredFunc";
-  TVM_DECLARE_NODE_TYPE_INFO(LoweredFuncNode);
+  TVM_DECLARE_NODE_TYPE_INFO(LoweredFuncNode, Node);
 };
 
 // Implementations of inline functions

include/tvm/operation.h

@@ -39,7 +39,7 @@ class PlaceholderOpNode : public OperationNode {
                         Type dtype);
 
   static constexpr const char* _type_key = "PlaceholderOp";
-  TVM_DECLARE_NODE_TYPE_INFO(PlaceholderOpNode);
+  TVM_DECLARE_NODE_TYPE_INFO(PlaceholderOpNode, OperationNode);
 };
 
 /*!
@@ -74,7 +74,7 @@ class ComputeOpNode : public OperationNode {
                         Expr body);
 
   static constexpr const char* _type_key = "ComputeOp";
-  TVM_DECLARE_NODE_TYPE_INFO(ComputeOpNode);
+  TVM_DECLARE_NODE_TYPE_INFO(ComputeOpNode, OperationNode);
 };
 
 /*!
@@ -123,7 +123,7 @@ class ScanOpNode : public OperationNode {
                         Array<Tensor> state_placeholder);
 
   static constexpr const char* _type_key = "ScanOp";
-  TVM_DECLARE_NODE_TYPE_INFO(ScanOpNode);
+  TVM_DECLARE_NODE_TYPE_INFO(ScanOpNode, OperationNode);
 };
 
 

include/tvm/packed_func_ext.h

@@ -33,7 +33,7 @@ struct NodeTypeChecker {
     // It can be turned off, but will make non strict checking.
     // TODO(tqchen) possibly find alternative to turn of RTTI
     using ContainerType = typename T::ContainerType;
-    return (dynamic_cast<ContainerType*>(sptr) != nullptr);
+    return sptr->derived_from<ContainerType>();
   }
   static inline void PrintName(std::ostringstream& os) { // NOLINT(*)
     using ContainerType = typename T::ContainerType;

include/tvm/runtime/c_runtime_api.h

@@ -153,6 +153,13 @@ typedef void* TVMRetValueHandle;
 typedef TVMArray* TVMArrayHandle;
 
 /*!
+ * \brief Used for implementing C API function.
+ *  Set last error message before return.
+ * \param msg The error message to be set.
+ */
+TVM_DLL void TVMAPISetLastError(const char* msg);
+
+/*!
  * \brief return str message of the last error
  *  all function in this file will return 0 when success
  *  and -1 when an error occured,
@@ -287,10 +294,10 @@ TVM_DLL int TVMCFuncSetReturn(TVMRetValueHandle ret,
  * \param num_args Number of arguments.
  * \param ret The return value handle.
  * \param resource_handle The handle additional resouce handle from fron-end.
- *
+ * \return 0 if success, -1 if failure happens, set error via TVMAPISetLastError.
  * \sa TVMCFuncSetReturn
  */
-typedef void (*TVMPackedCFunc)(
+typedef int (*TVMPackedCFunc)(
     TVMValue* args,
     int* type_codes,
     int num_args,

include/tvm/schedule.h

@@ -331,7 +331,7 @@ class StageNode : public Node {
   }
 
   static constexpr const char* _type_key = "Stage";
-  TVM_DECLARE_NODE_TYPE_INFO(StageNode);
+  TVM_DECLARE_NODE_TYPE_INFO(StageNode, Node);
 };
 
 /*! \brief node container for schedule */
@@ -354,7 +354,7 @@ class ScheduleNode : public Node {
   }
 
   static constexpr const char* _type_key = "Schedule";
-  TVM_DECLARE_NODE_TYPE_INFO(ScheduleNode);
+  TVM_DECLARE_NODE_TYPE_INFO(ScheduleNode, Node);
 };
 
 /*! \brief node container for IterVar attr */
@@ -368,11 +368,14 @@ class IterVarAttrNode : public Node {
   }
 
   static constexpr const char* _type_key = "IterVarAttr";
-  TVM_DECLARE_NODE_TYPE_INFO(IterVarAttrNode);
+  TVM_DECLARE_NODE_TYPE_INFO(IterVarAttrNode, Node);
 };
 
 /*! \brief base node of iteration var */
 class IterVarRelationNode : public Node {
+ public:
+  static constexpr const char* _type_key = "IterVarRelation";
+  TVM_DECLARE_BASE_NODE_INFO(IterVarRelationNode, Node);
 };
 
 /*!
@@ -402,7 +405,7 @@ class SplitNode : public IterVarRelationNode {
       IterVar inner, Expr factor);
 
   static constexpr const char* _type_key = "Split";
-  TVM_DECLARE_NODE_TYPE_INFO(SplitNode);
+  TVM_DECLARE_NODE_TYPE_INFO(SplitNode, IterVarRelationNode);
 };
 
 /*!
@@ -427,7 +430,7 @@ class FuseNode : public IterVarRelationNode {
       IterVar outer, IterVar inner, IterVar fused);
 
   static constexpr const char* _type_key = "Fuse";
-  TVM_DECLARE_NODE_TYPE_INFO(FuseNode);
+  TVM_DECLARE_NODE_TYPE_INFO(FuseNode, IterVarRelationNode);
 };
 
 /*!
@@ -450,7 +453,7 @@ class RebaseNode : public IterVarRelationNode {
   static IterVarRelation make(IterVar parent, IterVar rebased);
 
   static constexpr const char* _type_key = "Rebase";
-  TVM_DECLARE_NODE_TYPE_INFO(RebaseNode);
+  TVM_DECLARE_NODE_TYPE_INFO(RebaseNode, IterVarRelationNode);
 };
 
 

include/tvm/tensor.h

@@ -153,7 +153,7 @@ class TensorNode : public Node {
                      int value_index);
 
   static constexpr const char* _type_key = "Tensor";
-  TVM_DECLARE_NODE_TYPE_INFO(TensorNode);
+  TVM_DECLARE_NODE_TYPE_INFO(TensorNode, Node);
 };
 
 /*!
@@ -167,8 +167,6 @@ class OperationNode : public FunctionBaseNode {
   const std::string& func_name() const final {
     return name;
   }
-  /*! \return number of outputs of this op */
-  virtual int num_outputs() const = 0;
   /*! \return the list of iteration variable at root */
   virtual Array<IterVar> root_iter_vars() const = 0;
   /*! \return type of i-th output */
@@ -177,6 +175,8 @@ class OperationNode : public FunctionBaseNode {
   virtual Array<Expr> output_shape(size_t i) const = 0;
 
   static constexpr const char* _type_key = "Operation";
+
+  TVM_DECLARE_BASE_NODE_INFO(OperationNode, Node);
 };
 
 // Implementations of inline functions

make/config.mk

@@ -40,10 +40,11 @@ USE_CUDA = 1
 # whether use OpenCL during compile
 USE_OPENCL = 0
 
-# add the path to CUDA library to link and compile flag
-# if you have already add them to environment variable, leave it as NONE
-# USE_CUDA_PATH = /usr/local/cuda
-USE_CUDA_PATH = NONE
+# whether build with LLVM support
+# This requires llvm-config to be in your PATH
+# Requires LLVM version >= 4.0
+USE_LLVM = 0
 
-# whether use cuda runtime compiling for writing kernels in native language (i.e. Python)
-USE_NVRTC = 0
+# add the path to CUDA library to link and compile flag
+# if you have already add them to environment variable.
+# CUDA_PATH = /usr/local/cuda

python/tvm/_ctypes/_function.py

@@ -56,6 +56,7 @@ def convert_to_tvm_func(pyfunc):
             check_call(_LIB.TVMCFuncSetReturn(ret, values[0], ctypes.c_int(tcodes[0])))
             _ = temp_args
             _ = rv
+        return 0
 
     handle = FunctionHandle()
     f = TVMPackedCFunc(cfun)

python/tvm/_ctypes/_types.py

@@ -96,7 +96,7 @@ class TVMByteArray(ctypes.Structure):
 
 
 TVMPackedCFunc = ctypes.CFUNCTYPE(
-    None,
+    ctypes.c_int,
     ctypes.POINTER(TVMValue),
     ctypes.POINTER(ctypes.c_int),
     ctypes.c_int,

src/README.md

@@ -6,3 +6,4 @@
 - arithmetic Arithmetic expression and set simplification
 - pass The optimization pass on the IR structure
 - runtime Minimum runtime related codes.
+- codegen The code generator

src/api/api_codegen.cc

@@ -37,6 +37,11 @@ TVM_REGISTER_API(_codegen_BuildStackVM)
                         std::unordered_map<LoweredFunc, PackedFunc>());
   });
 
+TVM_REGISTER_API(_codegen_BuildLLVM)
+.set_body([](TVMArgs args, TVMRetValue *ret) {
+    *ret = BuildLLVM(args[0]);
+  });
+
 TVM_REGISTER_API(_codegen_BuildNVRTC)
 .set_body([](TVMArgs args, TVMRetValue *ret) {
     *ret = BuildNVRTC(args[0], args[1]);

src/arithmetic/int_set.h

@@ -20,7 +20,7 @@ enum SignType {
 };
 
 // internal node container of int set.
-class IntSetNode;
+struct IntSetNode;
 
 /*!
  * \brief Integer set class, represent a set of integers in one dimension.
@@ -104,6 +104,8 @@ class IntSet : public NodeRef {
  * \brief Base class of all IntSet containers.
  */
 struct IntSetNode : public Node {
+  static constexpr const char* _type_key = "IntSet";
+  TVM_DECLARE_BASE_NODE_INFO(IntSetNode, Node);
 };
 
 using ExprIntSetMap = std::unordered_map<Expr, IntSet,

src/arithmetic/int_set_internal.h

@@ -35,7 +35,7 @@ struct IntervalSet : public IntSetNode {
   }
 
   static constexpr const char* _type_key = "IntervalSet";
-  TVM_DECLARE_NODE_TYPE_INFO(IntervalSet);
+  TVM_DECLARE_NODE_TYPE_INFO(IntervalSet, IntSetNode);
 };
 
 /*!
@@ -51,7 +51,7 @@ struct StrideSet : public IntSetNode {
   Array<Expr> strides;
 
   static constexpr const char* _type_key = "StrideSet";
-  TVM_DECLARE_NODE_TYPE_INFO(StrideSet);
+  TVM_DECLARE_NODE_TYPE_INFO(StrideSet, IntSetNode);
 };
 
 }  // namespace arith

src/codegen/codegen_stack_vm.cc

@@ -272,9 +272,6 @@ inline void PushBinary(StackVM::OpCode op_int64,
   }
 }
 
-
-
-
 inline void PushCast(Type dst,
                      Type src,
                      CodeGenStackVM* p) {
@@ -496,7 +493,5 @@ TVM_STATIC_IR_FUNCTOR(CodeGenStackVM, vtable)
 .set_dispatch<Call>([](const Call *op, CodeGenStackVM* p) {
     p->Push_(op);
   });
-
-
 }  // namespace codegen
 }  // namespace tvm

src/codegen/llvm/codegen_llvm.h

+/*!
+ *  Copyright (c) 2017 by Contributors
+ * \file codegen_llvm.h
+ * \brief Common base class for generating into LLVM IR
+ */
+#ifndef TVM_CODEGEN_LLVM_CODEGEN_LLVM_H_
+#define TVM_CODEGEN_LLVM_CODEGEN_LLVM_H_
+#ifdef TVM_LLVM_VERSION
+
+#include <tvm/ir.h>
+#include <tvm/ir_visitor.h>
+#include <tvm/codegen.h>
+#include <memory>
+#include <vector>
+#include <string>
+#include "./llvm_common.h"
+
+namespace tvm {
+namespace codegen {
+
+using namespace ir;
+
+/*!
+ * \brief A base class to generate a LLVM.
+ */
+class CodeGenLLVM : public IRVisitor {
+ public:
+  /*!
+   * \brief Initialize the code generator with given context
+   * \param module_name The name of the module.
+   * \param ctx The context.
+   */
+  void Init(const std::string& module_name, llvm::LLVMContext* ctx);
+  /*!
+   * \brief Compile and add function f to the current module.
+   * \param f The function to be added.
+   */
+  void AddFunction(const LoweredFunc& f);
+  /*!
+   * \brief Finish current pass of codegen, get the module.
+   * \return the created module.
+   */
+  std::unique_ptr<llvm::Module> Finish();
+  /*!
+   * \brief Create Value for expression e
+   * \param e The expression to be created value for.
+   * \return created value.
+   */
+  llvm::Value* MakeValue(const Expr& e) {
+    value_ = nullptr;
+    this->Visit(e);
+    CHECK(value_ != nullptr);
+    return value_;
+  }
+  // Short hande code to get a constant int 32
+  llvm::Constant* ConstInt32(unsigned value) const {
+    return llvm::ConstantInt::get(t_int32_, value);
+  }
+  // override codegen
+  void Visit_(const Variable* op) final;
+  void Visit_(const Cast* op) final;
+  void Visit_(const IntImm* op) final;
+  void Visit_(const UIntImm* op) final;
+  void Visit_(const FloatImm* op) final;
+  void Visit_(const StringImm* op) final;
+  void Visit_(const Add* op) final;
+  void Visit_(const Sub* op) final;
+  void Visit_(const Mul* op) final;
+  void Visit_(const Div* op) final;
+  void Visit_(const Mod* op) final;
+  void Visit_(const Min* op) final;
+  void Visit_(const Max* op) final;
+  void Visit_(const LT* op) final;
+  void Visit_(const LE* op) final;
+  void Visit_(const GT* op) final;
+  void Visit_(const GE* op) final;
+  void Visit_(const EQ* op) final;
+  void Visit_(const NE* op) final;
+  void Visit_(const And* op) final;
+  void Visit_(const Or* op) final;
+  void Visit_(const Not* op) final;
+  void Visit_(const Select* op) final;
+  void Visit_(const Let* op) final;
+  void Visit_(const Load* op) final;
+  void Visit_(const Call* op) final;
+  void Visit_(const Ramp* op) final;
+  void Visit_(const Broadcast* op) final;
+  // stmt
+  void Visit_(const Store* op) final;
+  void Visit_(const For* op) final;
+  void Visit_(const IfThenElse* op) final;
+  void Visit_(const Allocate* op) final;
+  void Visit_(const AttrStmt* op) override;
+  void Visit_(const AssertStmt* op) final;
+  void Visit_(const LetStmt* op) final;
+  // create intrinstic given call
+  virtual llvm::Value* CreateIntrinstic(const Call* op);
+  // create extern function call
+  virtual llvm::Value* CreateCallExtern(const Call* op);
+  // create call into tvm packed function.
+  virtual llvm::Value* CreateCallPacked(const Call* op);
+
+ protected:
+  /*!
+   * \param t The original type.
+   * \return LLVM type of t
+   */
+  llvm::Type* LLVMType(const Type& t) const;
+  // do a scalarize call with f
+  llvm::Value* CreateScalarizedCall(
+      const Call* op, llvm::Function* f, const std::vector<llvm::Value*>& args);
+  // apply optimization on the module.
+  virtual void Optimize();
+  // The IRBuilder.
+  using IRBuilder = llvm::IRBuilder<llvm::ConstantFolder, llvm::IRBuilderDefaultInserter>;
+  // The current function
+  llvm::Function* function_;
+  // Internal builder
+  std::unique_ptr<IRBuilder> builder_;
+  // The module to be returned;
+  std::unique_ptr<llvm::Module> module_;
+  // Internal metabuilder
+  std::unique_ptr<llvm::MDBuilder> md_builder_;
+  // llvm context
+  llvm::LLVMContext* ctx_{nullptr};
+  // helpful data types
+  llvm::Type* t_void_{nullptr};
+  llvm::Type* t_void_p_{nullptr};
+  llvm::Type* t_int_{nullptr};
+  llvm::Type* t_char_{nullptr};
+  llvm::Type* t_int8_{nullptr};
+  llvm::Type* t_int16_{nullptr};
+  llvm::Type* t_int32_{nullptr};
+  llvm::Type* t_int64_{nullptr};
+  llvm::Type* t_float64_{nullptr};
+  // branch
+  llvm::MDNode* md_very_likely_branch_{nullptr};
+  llvm::MDNode* md_tbaa_root_{nullptr};
+  // TVM related data types
+  llvm::Type* t_tvm_index_{nullptr};
+  llvm::Type* t_tvm_func_handle_{nullptr};
+  llvm::StructType* t_tvm_context_{nullptr};
+  llvm::StructType* t_tvm_type_{nullptr};
+  llvm::StructType* t_tvm_array_{nullptr};
+  llvm::StructType* t_tvm_value_{nullptr};
+  // tvm api functions
+  llvm::Function* f_tvm_func_call_{nullptr};
+  llvm::Function* f_tvm_func_get_global_{nullptr};
+  llvm::Function* f_tvm_api_set_last_error_{nullptr};
+  // The acting body
+  llvm::BasicBlock* block_{nullptr};
+  // Last value returned codegen call.
+  llvm::Value* value_{nullptr};
+
+ private:
+  // comparison op
+  llvm::Value* GetVarValue(const Variable* v) const;
+  llvm::Value* CreateLT(Type t, llvm::Value* a, llvm::Value* b);
+  llvm::Value* CreateLE(Type t, llvm::Value* a, llvm::Value* b);
+  llvm::Value* CreateGT(Type t, llvm::Value* a, llvm::Value* b);
+  llvm::Value* CreateGE(Type t, llvm::Value* a, llvm::Value* b);
+  llvm::Value* CreateAdd(Type t, llvm::Value* a, llvm::Value* b);
+  llvm::Value* CreateSub(Type t, llvm::Value* a, llvm::Value* b);
+  llvm::Value* CreateMul(Type t, llvm::Value* a, llvm::Value* b);
+  llvm::Value* CreateBroadcast(llvm::Value* value, int lanes);
+  llvm::Value* GetConstString(const std::string& str);
+  llvm::Value* CreateBufferPtr(Type t, llvm::Value* buffer, llvm::Value* index);
+  llvm::Value* CreateCast(Type from, Type to, llvm::Value* value);
+  llvm::Value* GetPackedFuncHandle(const std::string& str, bool global);
+  // Check if the call to packed function is successful
+  // if not directly finalize function and pass on return code.
+  // return the end block after the check
+  llvm::BasicBlock* CheckPackedCallSuccess(llvm::Value* retcode);
+  // add alias information.
+  void AddAliasInfo(llvm::Instruction* load, const Variable* buffer, Expr index);
+  // The definition of local variable.
+  std::unordered_map<const Variable*, llvm::Value*> var_map_;
+  // global strings
+  std::unordered_map<std::string, llvm::Constant*> str_map_;
+  // global to packed function handle
+  std::unordered_map<std::string, llvm::GlobalVariable*> func_handle_map_;
+};
+}  // namespace codegen
+}  // namespace tvm
+#endif  // LLVM_VERSION
+#endif  // TVM_CODEGEN_LLVM_CODEGEN_LLVM_H_

src/codegen/llvm/llvm_common.cc

+/*!
+ *  Copyright (c) 2017 by Contributors
+ * \file llvm_common.cc
+ */
+#ifdef TVM_LLVM_VERSION
+
+#include <tvm/base.h>
+#include <mutex>
+#include "./llvm_common.h"
+
+namespace tvm {
+namespace codegen {
+
+struct LLVMEnv {
+  std::mutex mu;
+  bool native_initialized{false};
+
+  static LLVMEnv* Global() {
+    static LLVMEnv inst;
+    return &inst;
+  }
+};
+
+void InitializeLLVM() {
+  LLVMEnv* e = LLVMEnv::Global();
+  if (!e->native_initialized) {
+    std::lock_guard<std::mutex>(e->mu);
+    if (!e->native_initialized) {
+      e->native_initialized = true;
+      llvm::InitializeNativeTarget();
+      llvm::InitializeNativeTargetAsmPrinter();
+      llvm::InitializeNativeTargetAsmParser();
+    }
+  }
+}
+
+}  // namespace codegen
+}  // namespace tvm
+#endif  // TVM_LLVM_VERSION

src/codegen/llvm/llvm_common.h

+/*!
+ *  Copyright (c) 2017 by Contributors
+ * \file llvm_common.h
+ * \brief Common utilities for llvm initialization.
+ */
+#ifndef TVM_CODEGEN_LLVM_LLVM_COMMON_H_
+#define TVM_CODEGEN_LLVM_LLVM_COMMON_H_
+#ifdef TVM_LLVM_VERSION
+
+#include <llvm/ExecutionEngine/MCJIT.h>
+
+#include <llvm/IR/Value.h>
+#include <llvm/IR/Argument.h>
+#include <llvm/IR/BasicBlock.h>
+#include <llvm/IR/Constants.h>
+#include <llvm/IR/DerivedTypes.h>
+#include <llvm/IR/Function.h>
+#include <llvm/IR/IRBuilder.h>
+#include <llvm/IR/Instructions.h>
+#include <llvm/IR/LLVMContext.h>
+#include <llvm/IR/Module.h>
+#include <llvm/IR/Type.h>
+#include <llvm/IR/Intrinsics.h>
+#include <llvm/IR/MDBuilder.h>
+
+#include <llvm/IR/LegacyPassManager.h>
+#include <llvm/Transforms/IPO/PassManagerBuilder.h>
+#include <llvm/Transforms/IPO.h>
+
+#include <llvm/Support/Casting.h>
+#include <llvm/Support/TargetSelect.h>
+
+extern "C" {
+// Function signature for LLVM generated packed function.
+typedef int (*LLVMPackedCFunc)(void* args,
+                               int* type_codes,
+                               int num_args);
+}  // extern "C"
+
+namespace tvm {
+namespace codegen {
+
+/*!
+ * \brief Initialize LLVM on this process,
+ *  can be called multiple times.
+ */
+void InitializeLLVM();
+
+}  // namespace codegen
+}  // namespace tvm
+#endif  // TVM_LLVM_VERSION
+#endif  // TVM_CODEGEN_LLVM_LLVM_COMMON_H_

src/codegen/llvm/llvm_exec_engine.cc

+/*!
+ *  Copyright (c) 2017 by Contributors
+ * \file llvm_exec_engine.cc
+ */
+#include <tvm/runtime/packed_func.h>
+#include <tvm/codegen.h>
+#include "./llvm_common.h"
+#include "./codegen_llvm.h"
+
+namespace tvm {
+namespace codegen {
+
+using runtime::TVMArgs;
+using runtime::TVMRetValue;
+using runtime::PackedFunc;
+
+#ifdef TVM_LLVM_VERSION
+// Environment to keep jit resources alive.
+struct LLVMJITEnv {
+  std::shared_ptr<llvm::LLVMContext> ctx;
+  llvm::ExecutionEngine* ee{nullptr};
+  // constructor
+  LLVMJITEnv(std::shared_ptr<llvm::LLVMContext> ctx,
+             llvm::ExecutionEngine* ee)
+      : ctx(ctx), ee(ee) {
+  }
+  // destructor
+  ~LLVMJITEnv() {
+    if (ee != nullptr) {
+      ee->runStaticConstructorsDestructors(true);
+      delete ee;
+    }
+  }
+};
+
+
+PackedFunc JITCompile(std::unique_ptr<llvm::Module> module,
+                      std::shared_ptr<llvm::LLVMContext> ctx,
+                      const std::string& func_name) {
+  llvm::EngineBuilder builder(std::move(module));
+  builder.setEngineKind(llvm::EngineKind::JIT);
+  builder.setOptLevel(llvm::CodeGenOpt::Aggressive);
+  std::shared_ptr<LLVMJITEnv> env = std::make_shared<LLVMJITEnv>(
+      ctx, builder.create());
+  CHECK(env->ee != nullptr);
+  auto* faddr = reinterpret_cast<LLVMPackedCFunc>(
+      env->ee->getFunctionAddress(func_name));
+  env->ee->runStaticConstructorsDestructors(false);
+  return PackedFunc([env, faddr](TVMArgs args, TVMRetValue* rv) {
+      int ret = (*faddr)(
+          (void*)args.values, // NOLINT(*)
+          (int*)args.type_codes, // NOLINT(*)
+          args.num_args);
+      CHECK(ret == 0) << TVMGetLastError();
+    });
+}
+
+PackedFunc BuildLLVM(LoweredFunc func) {
+  InitializeLLVM();
+  // use one context per function.
+  std::shared_ptr<llvm::LLVMContext> ctx =
+      std::make_shared<llvm::LLVMContext>();
+  CodeGenLLVM cg;
+  cg.Init(func->name, ctx.get());
+  cg.AddFunction(func);
+  std::unique_ptr<llvm::Module> m = cg.Finish();
+  return JITCompile(std::move(m), ctx, func->name);
+}
+
+#else
+PackedFunc BuildLLVM(LoweredFunc func) {
+  LOG(FATAL) << "LLVM is not enabled";
+  return PackedFunc();
+}
+#endif  // TVM_LLVM_VERSION
+}  // namespace codegen
+}  // namespace tvm

src/runtime/runtime_base.h

@@ -21,8 +21,6 @@
  */
 #define API_END_HANDLE_ERROR(Finalize) } catch(std::runtime_error &_except_) { Finalize; return TVMAPIHandleException(_except_); } return 0; // NOLINT(*)
 
-void TVMAPISetLastError(const char* msg);
-
 /*!
  * \brief handle exception throwed out
  * \param e the exception

src/schedule/schedule_ops.cc

@@ -274,8 +274,9 @@ Stmt MakeLoop(const Stage& s,
     bound_state[iv] = false;
   }
   PassUpBoundCheck(s, dom_map, &bound_state);
-  auto nest = MakeLoopNest(s, dom_map, 0, false,
-                           bound_state, {}, &value_map);
+  auto nest = MakeLoopNest(
+      s, dom_map, 0, false,
+      bound_state, {{}}, &value_map);
 
   provide = Substitute(provide, value_map);
   if (init.defined()) {

tests/python/unittest/test_codegen_device.py

@@ -2,7 +2,6 @@ import tvm
 import numpy as np
 
 def test_add_pipeline():
-    """Not yet working, mock design"""
     n = tvm.Var('n')
     A = tvm.placeholder((n,), name='A')
     B = tvm.placeholder((n,), name='B')

tests/python/unittest/test_runtime_stack_vm.py → tests/python/unittest/test_codegen_stack_llvm.py

@@ -6,6 +6,16 @@ def tvm_call_global(*args):
     return tvm.make.Call("int32", "tvm_call_global", args, 4, None, 0)
 
 
+def run_jit(fapi, check):
+    for target in ["stackvm"]:
+        if target == "llvm":
+            f = tvm.codegen.BuildLLVM(fapi)
+        else:
+            f = tvm.codegen.BuildStackVM(fapi)
+        check(f)
+
+
+
 def test_stack_vm_basic():
     a = tvm.nd.array(np.zeros(10, dtype='float32'))
     @tvm.register_func
@@ -17,8 +27,7 @@ def test_stack_vm_basic():
     Ab = tvm.Buffer((n, ), tvm.float32)
     stmt = tvm.make.Evaluate(tvm_call_global("tvm_call_back_get_shape", Ab.shape[0]))
     fapi = tvm.ir_pass.MakeAPI(stmt, "print_shape", [Ab], 1)
-    f = tvm.codegen.BuildStackVM(fapi)
-    f(a)
+    run_jit(fapi, lambda f: f(a))
 
 
 @tvm.register_func
@@ -42,8 +51,10 @@ def test_stack_vm_loop():
     fapi = tvm.ir_pass.MakeAPI(stmt, "ramp", [Ab], 1)
     f = tvm.codegen.BuildStackVM(fapi)
     a = tvm.nd.array(np.zeros(10, dtype=dtype))
-    f(a)
-    np.testing.assert_equal(a.asnumpy(), np.arange(a.shape[0]))
+    def check(f):
+        f(a)
+        np.testing.assert_equal(a.asnumpy(), np.arange(a.shape[0]))
+    run_jit(fapi, check)
 
 
 def test_stack_vm_cond():
@@ -61,15 +72,46 @@ def test_stack_vm_cond():
             tvm.make.Store(Ab.data,
                            tvm.make.Load(dtype, Ab.data, i) + 2, i + 1)))
     fapi = tvm.ir_pass.MakeAPI(stmt, "test", [Ab], 1)
-    f = tvm.codegen.BuildStackVM(fapi)
-    a = tvm.nd.array(np.zeros(10, dtype=dtype))
-    f(a)
-    y = np.arange(a.shape[0]) * 2
-    y[5:] -= 1
-    np.testing.assert_equal(a.asnumpy(), y)
+    def check(f):
+        a = tvm.nd.array(np.zeros(10, dtype=dtype))
+        f(a)
+        y = np.arange(a.shape[0]) * 2
+        y[5:] -= 1
+        np.testing.assert_equal(a.asnumpy(), y)
+    run_jit(fapi, check)
 
 
+def test_llvm_add_pipeline():
+    n = tvm.Var('n')
+    A = tvm.placeholder((n,), name='A')
+    B = tvm.placeholder((n,), name='B')
+    C = tvm.compute(A.shape, lambda *i: A(*i) + B(*i), name='C')
+    s = tvm.Schedule(C.op)
+    bounds = tvm.schedule.InferBound(s)
+    stmt = tvm.schedule.ScheduleOps(s, bounds)
+    Ab = tvm.Buffer(A.shape, A.dtype, name='A')
+    Bb = tvm.Buffer(B.shape, B.dtype, name='B')
+    Cb = tvm.Buffer(C.shape, C.dtype, name='C')
+    stmt = tvm.ir_pass.StorageFlatten(stmt, {A: Ab, B:Bb, C:Cb})
+    stmt = tvm.ir_pass.Simplify(stmt)
+    fapi = tvm.ir_pass.MakeAPI(stmt, "myadd", [Ab, Bb, Cb], 3)
+
+    def check_llvm():
+        # build and invoke the kernel.
+        f = tvm.codegen.BuildLLVM(fapi)
+        ctx = tvm.cpu(0)
+        # launch the kernel.
+        n = 1027
+        a = tvm.nd.array(np.random.uniform(size=n).astype(Ab.dtype), ctx)
+        b = tvm.nd.array(np.random.uniform(size=n).astype(Bb.dtype), ctx)
+        c = tvm.nd.array(np.zeros(n, dtype=Cb.dtype), ctx)
+        f(a, b, c)
+        np.testing.assert_allclose(
+            c.asnumpy(), a.asnumpy() + b.asnumpy())
+    #check_llvm()
+
 if __name__ == "__main__":
     test_stack_vm_cond()
-    test_stack_vm_loop()
     test_stack_vm_basic()
+    test_stack_vm_loop()
+    test_llvm_add_pipeline()