[OpenMP] Base support for target directive codegen on NVPTX device.

Summary:
This patch adds base support for codegen of the target directive on the NVPTX device.

Reviewers: ABataev

Differential Revision: http://reviews.llvm.org/D17877

Reworked test case after buildbot failure on windows.
Updated patch to integrate r263837 and test case nvptx_target_firstprivate_codegen.cpp.

llvm-svn: 264018

clang/lib/CodeGen/CGOpenMPRuntime.cpp

@@ -4182,6 +4182,14 @@ void CGOpenMPRuntime::emitTargetOutlinedFunction(
     CGF.EmitStmt(CS.getCapturedStmt());
   };
 
+  emitTargetOutlinedFunctionHelper(D, ParentName, OutlinedFn, OutlinedFnID,
+                                   IsOffloadEntry, CodeGen);
+}
+
+void CGOpenMPRuntime::emitTargetOutlinedFunctionHelper(
+    const OMPExecutableDirective &D, StringRef ParentName,
+    llvm::Function *&OutlinedFn, llvm::Constant *&OutlinedFnID,
+    bool IsOffloadEntry, const RegionCodeGenTy &CodeGen) {
   // Create a unique name for the entry function using the source location
   // information of the current target region. The name will be something like:
   //
@@ -4203,6 +4211,8 @@ void CGOpenMPRuntime::emitTargetOutlinedFunction(
        << llvm::format("_%x_", FileID) << ParentName << "_l" << Line;
   }
 
+  const CapturedStmt &CS = *cast<CapturedStmt>(D.getAssociatedStmt());
+
   CodeGenFunction CGF(CGM, true);
   CGOpenMPTargetRegionInfo CGInfo(CS, CodeGen, EntryFnName);
   CodeGenFunction::CGCapturedStmtRAII CapInfoRAII(CGF, &CGInfo);

clang/lib/CodeGen/CGOpenMPRuntime.h

@@ -49,7 +49,31 @@ class CodeGenModule;
 typedef llvm::function_ref<void(CodeGenFunction &)> RegionCodeGenTy;
 
 class CGOpenMPRuntime {
+protected:
   CodeGenModule &CGM;
+
+  /// \brief Creates offloading entry for the provided entry ID \a ID,
+  /// address \a Addr and size \a Size.
+  virtual void createOffloadEntry(llvm::Constant *ID, llvm::Constant *Addr,
+                                  uint64_t Size);
+
+  /// \brief Helper to emit outlined function for 'target' directive.
+  /// \param D Directive to emit.
+  /// \param ParentName Name of the function that encloses the target region.
+  /// \param OutlinedFn Outlined function value to be defined by this call.
+  /// \param OutlinedFnID Outlined function ID value to be defined by this call.
+  /// \param IsOffloadEntry True if the outlined function is an offload entry.
+  /// \param CodeGen Lambda codegen specific to an accelerator device.
+  /// An oulined function may not be an entry if, e.g. the if clause always
+  /// evaluates to false.
+  virtual void emitTargetOutlinedFunctionHelper(const OMPExecutableDirective &D,
+                                                StringRef ParentName,
+                                                llvm::Function *&OutlinedFn,
+                                                llvm::Constant *&OutlinedFnID,
+                                                bool IsOffloadEntry,
+                                                const RegionCodeGenTy &CodeGen);
+
+private:
   /// \brief Default const ident_t object used for initialization of all other
   /// ident_t objects.
   llvm::Constant *DefaultOpenMPPSource = nullptr;
@@ -267,11 +291,6 @@ class CGOpenMPRuntime {
   /// compilation unit. The function that does the registration is returned.
   llvm::Function *createOffloadingBinaryDescriptorRegistration();
 
-  /// \brief Creates offloading entry for the provided entry ID \a ID,
-  /// address \a Addr and size \a Size.
-  void createOffloadEntry(llvm::Constant *ID, llvm::Constant *Addr,
-                          uint64_t Size);
-
   /// \brief Creates all the offload entries in the current compilation unit
   /// along with the associated metadata.
   void createOffloadEntriesAndInfoMetadata();