Backend: Add LLVM40 support

1.Refine APFloat fltSemantics.
2.Refine bitcode read/write header.
3.Refine clang invocation.
4.Refine return llvm::error handler.
5.Refine ilist_iterator usage.
6.Refine CFG Printer pass manager.
7.Refine GEP with pointer type changing.
8.Refine libocl 20 support
V2: Add missing ocl_sampler.ll and ocl_sampler_20.ll file
V3: Fix some build problem for llvm36

Signed-off-by: Pan Xiuli <xiuli.pan@intel.com>
Reviewed-by: Yang Rong <rong.r.yang@intel.com>

21 files changed, 217 insertions, 34 deletions

diff --git a/backend/src/backend/gen_program.cpp b/backend/src/backend/gen_program.cpp
index 998e340f..c1827b11 100644
--- a/backend/src/backend/gen_program.cpp
+++ b/backend/src/backend/gen_program.cpp
@@ -29,7 +29,11 @@
 #include "llvm/IR/DataLayout.h"
 #include "llvm-c/Linker.h"
 #include "llvm/Transforms/Utils/Cloning.h"
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+#include "llvm/Bitcode/BitcodeWriter.h"
+#else
 #include "llvm/Bitcode/ReaderWriter.h"
+#endif /* LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40 */
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/MemoryBuffer.h"
diff --git a/backend/src/backend/program.cpp b/backend/src/backend/program.cpp
index 6e8227a6..724058c6 100644
--- a/backend/src/backend/program.cpp
+++ b/backend/src/backend/program.cpp
@@ -62,7 +62,13 @@
 #include <clang/Basic/TargetOptions.h>
 #include <llvm/ADT/IntrusiveRefCntPtr.h>
 #include <llvm/IR/Module.h>
+
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+#include <llvm/Bitcode/BitcodeWriter.h>
+#include <clang/Lex/PreprocessorOptions.h>
+#else
 #include <llvm/Bitcode/ReaderWriter.h>
+#endif
 #include <llvm/Support/raw_ostream.h>
 #endif
 
@@ -694,14 +700,15 @@ namespace gbe {
     llvm::IntrusiveRefCntPtr<clang::DiagnosticIDs> DiagID(new clang::DiagnosticIDs());
     clang::DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
 
+    llvm::StringRef srcString(source);
     // Create the compiler invocation
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    auto CI = std::make_shared<clang::CompilerInvocation>();
+    CI->getPreprocessorOpts().addRemappedFile("stringInput.cl",
+#else
     std::unique_ptr<clang::CompilerInvocation> CI(new clang::CompilerInvocation);
-    clang::CompilerInvocation::CreateFromArgs(*CI,
-                                              &args[0],
-                                              &args[0] + args.size(),
-                                              Diags);
-    llvm::StringRef srcString(source);
     (*CI).getPreprocessorOpts().addRemappedFile("stringInput.cl",
+#endif
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR <= 35
                 llvm::MemoryBuffer::getMemBuffer(srcString)
 #else
@@ -709,9 +716,17 @@ namespace gbe {
 #endif
                 );
 
+    clang::CompilerInvocation::CreateFromArgs(*CI,
+                                              &args[0],
+                                              &args[0] + args.size(),
+                                              Diags);
     // Create the compiler instance
     clang::CompilerInstance Clang;
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    Clang.setInvocation(std::move(CI));
+#else
     Clang.setInvocation(CI.release());
+#endif
     // Get ready to report problems
     Clang.createDiagnostics(DiagClient, false);
 
diff --git a/backend/src/ir/half.cpp b/backend/src/ir/half.cpp
index 1c0d7eb9..0abc6cb3 100644
--- a/backend/src/ir/half.cpp
+++ b/backend/src/ir/half.cpp
@@ -29,7 +29,11 @@ namespace ir {
   {
     uint64_t v64 = static_cast<uint64_t>(v);
     llvm::APInt apInt(16, v64, false);
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    return llvm::APFloat(llvm::APFloat::IEEEhalf(), apInt);
+#else
     return llvm::APFloat(llvm::APFloat::IEEEhalf, apInt);
+#endif
   }
 
   static uint16_t convAPFloatToU16(const llvm::APFloat& apf)
@@ -42,14 +46,22 @@ namespace ir {
   half::operator float(void) const {
     bool loseInfo;
     llvm::APFloat apf_self = convU16ToAPFloat(this->val);
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    apf_self.convert(llvm::APFloat::IEEEsingle(), llvm::APFloat::rmNearestTiesToEven, &loseInfo);
+#else
     apf_self.convert(llvm::APFloat::IEEEsingle, llvm::APFloat::rmNearestTiesToEven, &loseInfo);
+#endif
     return apf_self.convertToFloat();
   }
 
   half::operator double(void) const {
     bool loseInfo;
     llvm::APFloat apf_self = convU16ToAPFloat(this->val);
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    apf_self.convert(llvm::APFloat::IEEEdouble(), llvm::APFloat::rmNearestTiesToEven, &loseInfo);
+#else
     apf_self.convert(llvm::APFloat::IEEEdouble, llvm::APFloat::rmNearestTiesToEven, &loseInfo);
+#endif
     return apf_self.convertToDouble();
   }
 
@@ -70,7 +82,11 @@ namespace ir {
   }
 
   half half::convToHalf(uint16_t u16) {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    llvm::APFloat res(llvm::APFloat::IEEEhalf(), llvm::APInt(16, 0, false));
+#else
     llvm::APFloat res(llvm::APFloat::IEEEhalf, llvm::APInt(16, 0, false));
+#endif
     uint64_t u64 = static_cast<uint64_t>(u16);
     llvm::APInt apInt(16, u64, false);
     res.convertFromAPInt(apInt, false, llvm::APFloat::rmNearestTiesToEven);
@@ -78,7 +94,11 @@ namespace ir {
   }
 
   half half::convToHalf(int16_t v16) {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    llvm::APFloat res(llvm::APFloat::IEEEhalf(), llvm::APInt(16, 0, true));
+#else
     llvm::APFloat res(llvm::APFloat::IEEEhalf, llvm::APInt(16, 0, true));
+#endif
     uint64_t u64 = static_cast<uint64_t>(v16);
     llvm::APInt apInt(16, u64, true);
     res.convertFromAPInt(apInt, true, llvm::APFloat::rmNearestTiesToEven);
diff --git a/backend/src/libocl/CMakeLists.txt b/backend/src/libocl/CMakeLists.txt
index c68ecb01..2917e6d2 100644
--- a/backend/src/libocl/CMakeLists.txt
+++ b/backend/src/libocl/CMakeLists.txt
@@ -211,7 +211,7 @@ MACRO(ADD_LL_TO_BC_TARGET M)
 	)
 ENDMACRO(ADD_LL_TO_BC_TARGET)
 
-SET (OCL_LL_MODULES_12 ocl_barrier ocl_clz ocl_ctz)
+SET (OCL_LL_MODULES_12 ocl_barrier ocl_clz ocl_ctz ocl_sampler)
 FOREACH(f ${OCL_LL_MODULES_12})
     COPY_THE_LL(${f})
     ADD_LL_TO_BC_TARGET(${f})
@@ -255,7 +255,7 @@ if (ENABLE_OPENCL_20)
     ADD_CL_TO_BC_TARGET(${f} ${bc_name} "${CLANG_OCL_FLAGS_20}")
   ENDFOREACH(f)
 
-  SET (OCL_LL_MODULES_20 ocl_barrier_20 ocl_clz_20 ocl_ctz_20 ocl_atomic_20)
+  SET (OCL_LL_MODULES_20 ocl_barrier_20 ocl_clz_20 ocl_ctz_20 ocl_atomic_20 ocl_sampler_20)
   FOREACH(f ${OCL_LL_MODULES_20})
     COPY_THE_LL(${f})
     ADD_LL_TO_BC_TARGET(${f})
diff --git a/backend/src/libocl/include/ocl_enqueue.h b/backend/src/libocl/include/ocl_enqueue.h
index 6479df71..7ccab59f 100644
--- a/backend/src/libocl/include/ocl_enqueue.h
+++ b/backend/src/libocl/include/ocl_enqueue.h
@@ -38,7 +38,7 @@ struct Block_literal {
   void *isa; // initialized to &_NSConcreteStackBlock or &_NSConcreteGlobalBlock
   int flags;
   int reserved;
-  __global void (*invoke)(void *, ...);
+  __global void* invoke;
   struct Block_descriptor_1 {
     unsigned long int reserved;         // NULL
     unsigned long int size;         // sizeof(struct Block_literal_1)
@@ -65,10 +65,6 @@ OVERLOADABLE int enqueue_kernel(queue_t q, int flag, ndrange_t ndrange, void (^b
 OVERLOADABLE int enqueue_kernel(queue_t q, int flag, ndrange_t ndrange,
                                 uint num_events_in_wait_list, const clk_event_t *event_wait_list,
                                 clk_event_t *event_ret, void (^block)(void));
-OVERLOADABLE int enqueue_kernel(queue_t q, int flag, ndrange_t ndrange, __private void *block, uint size0, ...);
-OVERLOADABLE int enqueue_kernel(queue_t q, int flag, ndrange_t ndrange,
-                                uint num_events_in_wait_list, const clk_event_t *event_wait_list,
-                                clk_event_t *event_ret,  __private void *block, uint size0, ...);
 
 queue_t get_default_queue(void);
 int __gen_enqueue_kernel(queue_t q, int flag, ndrange_t ndrange, void (^block)(void), int size);
diff --git a/backend/src/libocl/src/ocl_image.cl b/backend/src/libocl/src/ocl_image.cl
index 2febfdac..e66aa155 100644
--- a/backend/src/libocl/src/ocl_image.cl
+++ b/backend/src/libocl/src/ocl_image.cl
@@ -295,17 +295,18 @@ GEN_VALIDATE_ARRAY_INDEX(int, read_write image1d_buffer_t)
 // The work around is to use a LD message instead of normal sample message.
 ///////////////////////////////////////////////////////////////////////////////
 
-bool __gen_ocl_sampler_need_fix(sampler_t);
-bool __gen_ocl_sampler_need_rounding_fix(sampler_t);
+bool __gen_ocl_sampler_need_fix(int);
+bool __gen_ocl_sampler_need_rounding_fix(int);
+int __gen_ocl_sampler_to_int(sampler_t);
 
 bool __gen_sampler_need_fix(const sampler_t sampler)
 {
-  return __gen_ocl_sampler_need_fix(sampler);
+  return __gen_ocl_sampler_need_fix(__gen_ocl_sampler_to_int(sampler));
 }
 
 bool __gen_sampler_need_rounding_fix(const sampler_t sampler)
 {
-  return __gen_ocl_sampler_need_rounding_fix(sampler);
+  return __gen_ocl_sampler_need_rounding_fix(__gen_ocl_sampler_to_int(sampler));
 }
 
 INLINE_OVERLOADABLE float __gen_fixup_float_coord(float tmpCoord)
diff --git a/backend/src/libocl/src/ocl_sampler.ll b/backend/src/libocl/src/ocl_sampler.ll
new file mode 100644
index 00000000..6d39fdb2
--- /dev/null
+++ b/backend/src/libocl/src/ocl_sampler.ll
@@ -0,0 +1,10 @@
+target datalayout = "e-p:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir"
+%opencl.sampler_t = type opaque
+
+declare %opencl.sampler_t addrspace(2)*@__gen_ocl_int_to_sampler(i32)
+
+define %opencl.sampler_t addrspace(2)*@__translate_sampler_initializer(i32 %s) {
+  %call = call %opencl.sampler_t addrspace(2)*@__gen_ocl_int_to_sampler(i32 %s)
+  ret %opencl.sampler_t addrspace(2)* %call
+}
diff --git a/backend/src/libocl/src/ocl_sampler_20.ll b/backend/src/libocl/src/ocl_sampler_20.ll
new file mode 100644
index 00000000..bea6d755
--- /dev/null
+++ b/backend/src/libocl/src/ocl_sampler_20.ll
@@ -0,0 +1,10 @@
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir64"
+%opencl.sampler_t = type opaque
+
+declare %opencl.sampler_t addrspace(2)*@__gen_ocl_int_to_sampler(i32)
+
+define %opencl.sampler_t addrspace(2)*@__translate_sampler_initializer(i32 %s) {
+  %call = call %opencl.sampler_t addrspace(2)*@__gen_ocl_int_to_sampler(i32 %s)
+  ret %opencl.sampler_t addrspace(2)* %call
+}
diff --git a/backend/src/llvm/ExpandUtils.cpp b/backend/src/llvm/ExpandUtils.cpp
index a09d9908..cb1736b7 100644
--- a/backend/src/llvm/ExpandUtils.cpp
+++ b/backend/src/llvm/ExpandUtils.cpp
@@ -101,7 +101,11 @@ namespace llvm {
   Function *RecreateFunction(Function *Func, FunctionType *NewType) {
     Function *NewFunc = Function::Create(NewType, Func->getLinkage());
     NewFunc->copyAttributesFrom(Func);
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    Func->getParent()->getFunctionList().insert(Func->getIterator(), NewFunc);
+#else
     Func->getParent()->getFunctionList().insert(ilist_iterator<Function>(Func), NewFunc);
+#endif
     NewFunc->takeName(Func);
     NewFunc->getBasicBlockList().splice(NewFunc->begin(),
                                         Func->getBasicBlockList());
diff --git a/backend/src/llvm/llvm_barrier_nodup.cpp b/backend/src/llvm/llvm_barrier_nodup.cpp
index 727e6bd2..a7d0d1ad 100644
--- a/backend/src/llvm/llvm_barrier_nodup.cpp
+++ b/backend/src/llvm/llvm_barrier_nodup.cpp
@@ -48,7 +48,12 @@ namespace gbe {
 
       }
 
-      virtual const char *getPassName() const {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+      virtual StringRef getPassName() const
+#else
+      virtual const char *getPassName() const
+#endif
+      {
         return "SPIR backend: set barrier no duplicate attr";
       }
 
diff --git a/backend/src/llvm/llvm_bitcode_link.cpp b/backend/src/llvm/llvm_bitcode_link.cpp
index 869db89c..5c6585d0 100644
--- a/backend/src/llvm/llvm_bitcode_link.cpp
+++ b/backend/src/llvm/llvm_bitcode_link.cpp
@@ -117,17 +117,28 @@ namespace gbe
 
         std::string ErrInfo;// = "Not Materializable";
         if (!fromSrc && newMF->isMaterializable()) {
-#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR <= 35
-          if (newMF->Materialize(&ErrInfo)) {
-            printf("Can not materialize the function: %s, because %s\n", fnName.c_str(), ErrInfo.c_str());
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+          if (llvm::Error EC = newMF->materialize()) {
+            std::string Msg;
+            handleAllErrors(std::move(EC), [&](ErrorInfoBase &EIB) {
+              Msg = EIB.message();
+            });
+            printf("Can not materialize the function: %s, because %s\n", fnName.c_str(), Msg.c_str());
             return false;
           }
-#else
+          Gvs.push_back((GlobalValue *)newMF);
+#elif LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 36
           if (std::error_code EC = newMF->materialize()) {
             printf("Can not materialize the function: %s, because %s\n", fnName.c_str(), EC.message().c_str());
             return false;
           }
           Gvs.push_back((GlobalValue *)newMF);
+#else
+         if (newMF->Materialize(&ErrInfo)) {
+            printf("Can not materialize the function: %s, because %s\n", fnName.c_str(), ErrInfo.c_str());
+            return false;
+          }
+
 #endif
         }
         if (!materializedFuncCall(src, lib, *newMF, MFS, Gvs))
@@ -250,21 +261,30 @@ namespace gbe
       }
       std::string ErrInfo;// = "Not Materializable";
       if (newMF->isMaterializable()) {
-#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR <= 35
-        if (newMF->Materialize(&ErrInfo)) {
-          printf("Can not materialize the function: %s, because %s\n", fnName.c_str(), ErrInfo.c_str());
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+        if (llvm::Error EC = newMF->materialize()) {
+          std::string Msg;
+          handleAllErrors(std::move(EC), [&](ErrorInfoBase &EIB) {
+            Msg = EIB.message();
+          });
+          printf("Can not materialize the function: %s, because %s\n", fnName.c_str(), Msg.c_str());
           delete clonedLib;
           return NULL;
         }
-      }
-#else
+#elif LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 36
         if (std::error_code EC = newMF->materialize()) {
           printf("Can not materialize the function: %s, because %s\n", fnName.c_str(), EC.message().c_str());
           delete clonedLib;
           return NULL;
         }
-      }
+#else
+        if (newMF->Materialize(&ErrInfo)) {
+          printf("Can not materialize the function: %s, because %s\n", fnName.c_str(), ErrInfo.c_str());
+          delete clonedLib;
+          return NULL;
+        }
 #endif
+      }
 
       if (!materializedFuncCall(*mod, *clonedLib, *newMF, materializedFuncs, Gvs)) {
         delete clonedLib;
@@ -292,7 +312,12 @@ namespace gbe
     Module::GlobalListType &GVlist = clonedLib->getGlobalList();
     for(Module::global_iterator GVitr = GVlist.begin();GVitr != GVlist.end();++GVitr) {
       GlobalValue * GV = &*GVitr;
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+      ExitOnError ExitOnErr("Can not materialize the clonedLib: ");
+      ExitOnErr(clonedLib->materialize(GV));
+#else
       clonedLib->materialize(GV);
+#endif
       Gvs.push_back(GV);
     }
     llvm::legacy::PassManager Extract;
@@ -300,8 +325,13 @@ namespace gbe
     Extract.add(createGVExtractionPass(Gvs, false));
     Extract.run(*clonedLib);
     /* Mark the library module as materialized for later use. */
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    ExitOnError ExitOnErr("Can not materialize the clonedLib: ");
+    ExitOnErr(clonedLib->materializeAll());
+#else
     clonedLib->materializeAll();
 #endif
+#endif
 
     /* the SPIR binary datalayout maybe different with beignet's bitcode */
     if(clonedLib->getDataLayout() != mod->getDataLayout())
@@ -309,14 +339,14 @@ namespace gbe
 
     /* We use beignet's bitcode as dst because it will have a lot of
        lazy functions which will not be loaded. */
-    char* errorMsg;
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
     if(LLVMLinkModules2(wrap(clonedLib), wrap(mod))) {
 #else
+    char* errorMsg;
     if(LLVMLinkModules(wrap(clonedLib), wrap(mod), LLVMLinkerDestroySource, &errorMsg)) {
+      printf("Fatal Error: link the bitcode error:\n%s\n", errorMsg);
 #endif
       delete clonedLib;
-      printf("Fatal Error: link the bitcode error:\n%s\n", errorMsg);
       return NULL;
     }
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 37
diff --git a/backend/src/llvm/llvm_gen_backend.cpp b/backend/src/llvm/llvm_gen_backend.cpp
index fa45a420..a106259f 100644
--- a/backend/src/llvm/llvm_gen_backend.cpp
+++ b/backend/src/llvm/llvm_gen_backend.cpp
@@ -357,6 +357,15 @@ namespace gbe
       GBE_ASSERT(! (isa<Constant>(value) && !isa<GlobalValue>(value)));
       Type *type = value->getType();
       auto typeID = type->getTypeID();
+      if (typeID == Type::PointerTyID)
+      {
+        Type *eltTy = dyn_cast<PointerType>(type)->getElementType();
+        if (eltTy->isStructTy()) {
+          StructType *strTy = dyn_cast<StructType>(eltTy);
+          if (strTy->getName().data() && strstr(strTy->getName().data(), "sampler"))
+            type = Type::getInt32Ty(value->getContext());
+        }
+      }
       switch (typeID) {
         case Type::IntegerTyID:
         case Type::FloatTyID:
@@ -573,7 +582,11 @@ namespace gbe
       pass = PASS_EMIT_REGISTERS;
     }
 
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    virtual llvm::StringRef getPassName() const { return "Gen Back-End"; }
+#else
     virtual const char *getPassName() const { return "Gen Back-End"; }
+#endif
 
     void getAnalysisUsage(AnalysisUsage &AU) const {
 #if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 37
@@ -2410,10 +2423,11 @@ namespace gbe
         }
 
         if (llvmInfo.isSamplerType()) {
-          ctx.input(argName, ir::FunctionArgument::SAMPLER, reg, llvmInfo, getTypeByteSize(unit, type), getAlignmentByte(unit, type), 0);
+          ctx.input(argName, ir::FunctionArgument::SAMPLER, reg, llvmInfo, 4, 4, 0);
           (void)ctx.getFunction().getSamplerSet()->append(reg, &ctx);
           continue;
         }
+
         if(llvmInfo.isPipeType()) {
           llvmInfo.typeSize = getTypeSize(F.getParent(),unit,llvmInfo.typeName);
           ctx.input(argName, ir::FunctionArgument::PIPE, reg, llvmInfo, getTypeByteSize(unit, type), getAlignmentByte(unit, type), BtiMap.find(&*I)->second);
@@ -4070,6 +4084,15 @@ namespace gbe
         regTranslator.newValueProxy(srcValue, dst);
         break;
       }
+      case GEN_OCL_INT_TO_SAMPLER:
+      case GEN_OCL_SAMPLER_TO_INT:
+      {
+        Value *srcValue = I.getOperand(0);
+        //srcValue->dump();
+        //dst->dump();
+        regTranslator.newValueProxy(srcValue, dst);
+        break;
+      }
       case GEN_OCL_ENQUEUE_GET_ENQUEUE_INFO_ADDR:
         regTranslator.newScalarProxy(ir::ocl::enqueuebufptr, dst);
         break;
@@ -4576,10 +4599,19 @@ namespace gbe
   /* append a new sampler. should be called before any reference to
    * a sampler_t value. */
   uint8_t GenWriter::appendSampler(CallSite::arg_iterator AI) {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    CallInst *TC = dyn_cast<CallInst>(*AI);
+    Constant *CPV = TC ? dyn_cast<Constant>(TC->getOperand(0)) : NULL;
+#else
     Constant *CPV = dyn_cast<Constant>(*AI);
+#endif
     uint8_t index;
     if (CPV != NULL)
     {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+      // Check if the Callee is sampler convert function
+      GBE_ASSERT(TC->getCalledFunction()->getName().str() == "__gen_ocl_int_to_sampler");
+#endif
       // This is not a kernel argument sampler, we need to append it to sampler set,
       // and allocate a sampler slot for it.
       const ir::Immediate &x = processConstantImm(CPV);
@@ -5583,6 +5615,8 @@ namespace gbe
           case GEN_OCL_GET_PIPE:
           case GEN_OCL_MAKE_RID:
           case GEN_OCL_GET_RID:
+          case GEN_OCL_INT_TO_SAMPLER:
+          case GEN_OCL_SAMPLER_TO_INT:
           {
             break;
           }
diff --git a/backend/src/llvm/llvm_gen_ocl_function.hxx b/backend/src/llvm/llvm_gen_ocl_function.hxx
index 5682c45d..b0566423 100644
--- a/backend/src/llvm/llvm_gen_ocl_function.hxx
+++ b/backend/src/llvm/llvm_gen_ocl_function.hxx
@@ -279,3 +279,7 @@ DECL_LLVM_GEN_FUNCTION(MAKE_RID, __gen_ocl_make_rid)
 DECL_LLVM_GEN_FUNCTION(ENQUEUE_SET_NDRANGE_INFO, __gen_ocl_set_ndrange_info)
 DECL_LLVM_GEN_FUNCTION(ENQUEUE_GET_NDRANGE_INFO, __gen_ocl_get_ndrange_info)
 DECL_LLVM_GEN_FUNCTION(ENQUEUE_GET_ENQUEUE_INFO_ADDR, __gen_ocl_get_enqueue_info_addr)
+
+// sampler helper functions
+DECL_LLVM_GEN_FUNCTION(SAMPLER_TO_INT, __gen_ocl_sampler_to_int)
+DECL_LLVM_GEN_FUNCTION(INT_TO_SAMPLER, __gen_ocl_int_to_sampler)
diff --git a/backend/src/llvm/llvm_includes.hpp b/backend/src/llvm/llvm_includes.hpp
index a242fd34..184553af 100644
--- a/backend/src/llvm/llvm_includes.hpp
+++ b/backend/src/llvm/llvm_includes.hpp
@@ -24,6 +24,7 @@
 #ifndef __GBE_IR_LLVM_INCLUDES_HPP__
 #define __GBE_IR_LLVM_INCLUDES_HPP__
 
+#ifdef GBE_COMPILER_AVAILABLE
 #include "llvm/Config/llvm-config.h"
 
 #include "llvm/IR/BasicBlock.h"
@@ -75,7 +76,12 @@
 
 #include "llvm-c/Linker.h"
 #include "llvm/IRReader/IRReader.h"
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+#include <llvm/Bitcode/BitcodeWriter.h>
+//#include <llvm/Bitcode/BitcodeReader.h>
+#else
 #include "llvm/Bitcode/ReaderWriter.h"
+#endif
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 
@@ -132,4 +138,10 @@
 #include "llvm/Transforms/Scalar/GVN.h"
 #endif
 
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 39
+#include "llvm/Support/Error.h"
+#endif
+
+#endif /*GBE_COMPILER_AVAILABLE */
+
 #endif /* __GBE_IR_LLVM_INCLUDES_HPP__ */
diff --git a/backend/src/llvm/llvm_intrinsic_lowering.cpp b/backend/src/llvm/llvm_intrinsic_lowering.cpp
index f01bb516..57c933f5 100644
--- a/backend/src/llvm/llvm_intrinsic_lowering.cpp
+++ b/backend/src/llvm/llvm_intrinsic_lowering.cpp
@@ -40,7 +40,12 @@ namespace gbe {
 
       }
 
-      virtual const char *getPassName() const {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+      virtual StringRef getPassName() const
+#else
+      virtual const char *getPassName() const
+#endif
+      {
         return "SPIR backend: lowering instrinsics";
       }
       static char convertSpaceToName(Value *val) {
diff --git a/backend/src/llvm/llvm_loadstore_optimization.cpp b/backend/src/llvm/llvm_loadstore_optimization.cpp
index 4f4639c0..5aa38bef 100644
--- a/backend/src/llvm/llvm_loadstore_optimization.cpp
+++ b/backend/src/llvm/llvm_loadstore_optimization.cpp
@@ -75,8 +75,12 @@ namespace gbe {
                                   const BasicBlock::iterator &start,
                                   unsigned maxVecSize,
                                   bool isLoad);
-
-    virtual const char *getPassName() const {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    virtual StringRef getPassName() const
+#else
+    virtual const char *getPassName() const
+#endif
+    {
       return "Merge compatible Load/stores for Gen";
     }
   };
diff --git a/backend/src/llvm/llvm_passes.cpp b/backend/src/llvm/llvm_passes.cpp
index f414fbbd..10752a35 100644
--- a/backend/src/llvm/llvm_passes.cpp
+++ b/backend/src/llvm/llvm_passes.cpp
@@ -232,7 +232,11 @@ namespace gbe
       AU.setPreservesCFG();
     }
 
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    virtual StringRef getPassName() const {
+#else
     virtual const char *getPassName() const {
+#endif
       return "SPIR backend: insert special spir instructions";
     }
 
diff --git a/backend/src/llvm/llvm_printf_parser.cpp b/backend/src/llvm/llvm_printf_parser.cpp
index a1b1c2c9..6bb7c52a 100644
--- a/backend/src/llvm/llvm_printf_parser.cpp
+++ b/backend/src/llvm/llvm_printf_parser.cpp
@@ -309,7 +309,11 @@ error:
     bool parseOnePrintfInstruction(CallInst * call);
     bool generateOneParameterInst(PrintfSlot& slot, Value* arg, Value*& new_arg);
 
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    virtual StringRef getPassName() const
+#else
     virtual const char *getPassName() const
+#endif
     {
       return "Printf Parser";
     }
@@ -515,7 +519,11 @@ error:
       case Type::FloatTyID: {
         /* llvm 3.6 will give a undef value for NAN. */
         if (dyn_cast<llvm::UndefValue>(arg)) {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+          APFloat nan = APFloat::getNaN(APFloat::IEEEsingle(), false);
+#else
           APFloat nan = APFloat::getNaN(APFloat::IEEEsingle, false);
+#endif
           new_arg = ConstantFP::get(module->getContext(), nan);
         }
 
diff --git a/backend/src/llvm/llvm_profiling.cpp b/backend/src/llvm/llvm_profiling.cpp
index bc169516..f7e4cc53 100644
--- a/backend/src/llvm/llvm_profiling.cpp
+++ b/backend/src/llvm/llvm_profiling.cpp
@@ -83,7 +83,11 @@ namespace gbe
     {
     }
 
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+    virtual StringRef getPassName() const
+#else
     virtual const char *getPassName() const
+#endif
     {
       return "Timestamp Parser";
     }
diff --git a/backend/src/llvm/llvm_to_gen.cpp b/backend/src/llvm/llvm_to_gen.cpp
index 9b3b1f4e..37919ec6 100644
--- a/backend/src/llvm/llvm_to_gen.cpp
+++ b/backend/src/llvm/llvm_to_gen.cpp
@@ -402,9 +402,17 @@ namespace gbe
     passes.add(createScalarizePass());             // Expand all vector ops
 
     if(OCL_OUTPUT_CFG)
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+      passes.add(createCFGPrinterLegacyPassPass());
+#else
       passes.add(createCFGPrinterPass());
+#endif
     if(OCL_OUTPUT_CFG_ONLY)
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+      passes.add(createCFGOnlyPrinterLegacyPassPass());
+#else
       passes.add(createCFGOnlyPrinterPass());
+#endif
     passes.add(createGenPass(unit));
     passes.run(mod);
     errors = dc.str();
diff --git a/backend/src/llvm/llvm_unroll.cpp b/backend/src/llvm/llvm_unroll.cpp
index bfd3bbe3..107d7937 100644
--- a/backend/src/llvm/llvm_unroll.cpp
+++ b/backend/src/llvm/llvm_unroll.cpp
@@ -238,7 +238,12 @@ namespace gbe {
         return true;
       }
 
-      virtual const char *getPassName() const {
+#if LLVM_VERSION_MAJOR * 10 + LLVM_VERSION_MINOR >= 40
+      virtual StringRef getPassName() const
+#else
+      virtual const char *getPassName() const
+#endif
+      {
         return "SPIR backend: custom loop unrolling pass";
       }