[OPENMP50]Support for declare variant directive for NVPTX target.

NVPTX does not support global aliases. Instead, we have to copy the full
body of the variant function for the original function.

llvm-svn: 374387

1 files changed, 44 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 080914afcc9..eab48ccb9b7 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2742,6 +2742,50 @@ void CodeGenModule::EmitMultiVersionFunctionDefinition(GlobalDecl GD,
     EmitGlobalFunctionDefinition(GD, GV);
 }
 
+void CodeGenModule::emitOpenMPDeviceFunctionRedefinition(
+    GlobalDecl OldGD, GlobalDecl NewGD, llvm::GlobalValue *GV) {
+  assert(getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice &&
+         OpenMPRuntime && "Expected OpenMP device mode.");
+  const auto *D = cast<FunctionDecl>(OldGD.getDecl());
+
+  // Compute the function info and LLVM type.
+  const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(OldGD);
+  llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
+
+  // Get or create the prototype for the function.
+  if (!GV || (GV->getType()->getElementType() != Ty)) {
+    GV = cast<llvm::GlobalValue>(GetOrCreateLLVMFunction(
+        getMangledName(OldGD), Ty, GlobalDecl(), /*ForVTable=*/false,
+        /*DontDefer=*/true, /*IsThunk=*/false, llvm::AttributeList(),
+        ForDefinition));
+    SetFunctionAttributes(OldGD, cast<llvm::Function>(GV),
+                          /*IsIncompleteFunction=*/false,
+                          /*IsThunk=*/false);
+  }
+  // We need to set linkage and visibility on the function before
+  // generating code for it because various parts of IR generation
+  // want to propagate this information down (e.g. to local static
+  // declarations).
+  auto *Fn = cast<llvm::Function>(GV);
+  setFunctionLinkage(OldGD, Fn);
+
+  // FIXME: this is redundant with part of
+  // setFunctionDefinitionAttributes
+  setGVProperties(Fn, OldGD);
+
+  MaybeHandleStaticInExternC(D, Fn);
+
+  maybeSetTrivialComdat(*D, *Fn);
+
+  CodeGenFunction(*this).GenerateCode(NewGD, Fn, FI);
+
+  setNonAliasAttributes(OldGD, Fn);
+  SetLLVMFunctionAttributesForDefinition(D, Fn);
+
+  if (D->hasAttr<AnnotateAttr>())
+    AddGlobalAnnotations(D, Fn);
+}
+
 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
   const auto *D = cast<ValueDecl>(GD.getDecl());