From a3ce7f5cd2ae236bec7752e343f4b63ddda7ebe7 Mon Sep 17 00:00:00 2001
From: "Yaxun (Sam) Liu" <yaxun.liu@amd.com>
Date: Fri, 5 Feb 2021 14:40:16 -0500
Subject: [HIP] Fix managed variable linkage

Currently managed variables are emitted as undefined symbols, which
causes difficulty for diagnosing undefined symbols for non-managed
variables.

This patch transforms managed variables in device compilation so that
they can be emitted as normal variables.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D96195
---
 clang/lib/CodeGen/CodeGenModule.cpp | 33 +++++++++++++++------------------
 1 file changed, 15 insertions(+), 18 deletions(-)

(limited to 'clang/lib/CodeGen/CodeGenModule.cpp')

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index d568e3d7095c..7e45ae3acb3e 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -459,10 +459,8 @@ void CodeGenModule::Release() {
   if (ObjCRuntime)
     if (llvm::Function *ObjCInitFunction = ObjCRuntime->ModuleInitFunction())
       AddGlobalCtor(ObjCInitFunction);
-  if (Context.getLangOpts().CUDA && !Context.getLangOpts().CUDAIsDevice &&
-      CUDARuntime) {
-    if (llvm::Function *CudaCtorFunction =
-            CUDARuntime->makeModuleCtorFunction())
+  if (Context.getLangOpts().CUDA && CUDARuntime) {
+    if (llvm::Function *CudaCtorFunction = CUDARuntime->finalizeModule())
       AddGlobalCtor(CudaCtorFunction);
   }
   if (OpenMPRuntime) {
@@ -3833,8 +3831,14 @@ CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
     }
   }
 
-  if (GV->isDeclaration())
+  if (GV->isDeclaration()) {
     getTargetCodeGenInfo().setTargetAttributes(D, GV, *this);
+    // External HIP managed variables needed to be recorded for transformation
+    // in both device and host compilations.
+    if (getLangOpts().CUDA && D && D->hasAttr<HIPManagedAttr>() &&
+        D->hasExternalStorage())
+      getCUDARuntime().handleVarRegistration(D, *GV);
+  }
 
   LangAS ExpectedAS =
       D ? D->getType().getAddressSpace()
@@ -4142,12 +4146,8 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
   bool NeedsGlobalDtor =
       D->needsDestruction(getContext()) == QualType::DK_cxx_destructor;
 
-  bool IsHIPManagedVarOnDevice =
-      getLangOpts().CUDAIsDevice && D->hasAttr<HIPManagedAttr>();
-
   const VarDecl *InitDecl;
-  const Expr *InitExpr =
-      IsHIPManagedVarOnDevice ? nullptr : D->getAnyInitializer(InitDecl);
+  const Expr *InitExpr = D->getAnyInitializer(InitDecl);
 
   Optional<ConstantEmitter> emitter;
 
@@ -4158,15 +4158,15 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
       getLangOpts().CUDAIsDevice && D->hasAttr<CUDASharedAttr>();
   // Shadows of initialized device-side global variables are also left
   // undefined.
+  // Managed Variables should be initialized on both host side and device side.
   bool IsCUDAShadowVar =
       !getLangOpts().CUDAIsDevice && !D->hasAttr<HIPManagedAttr>() &&
       (D->hasAttr<CUDAConstantAttr>() || D->hasAttr<CUDADeviceAttr>() ||
        D->hasAttr<CUDASharedAttr>());
   bool IsCUDADeviceShadowVar =
-      getLangOpts().CUDAIsDevice &&
+      getLangOpts().CUDAIsDevice && !D->hasAttr<HIPManagedAttr>() &&
       (D->getType()->isCUDADeviceBuiltinSurfaceType() ||
-       D->getType()->isCUDADeviceBuiltinTextureType() ||
-       D->hasAttr<HIPManagedAttr>());
+       D->getType()->isCUDADeviceBuiltinTextureType());
   if (getLangOpts().CUDA &&
       (IsCUDASharedVar || IsCUDAShadowVar || IsCUDADeviceShadowVar))
     Init = llvm::UndefValue::get(getTypes().ConvertType(ASTTy));
@@ -4273,14 +4273,11 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
         GV->setExternallyInitialized(true);
     } else {
       getCUDARuntime().internalizeDeviceSideVar(D, Linkage);
-      getCUDARuntime().handleVarRegistration(D, *GV);
     }
+    getCUDARuntime().handleVarRegistration(D, *GV);
   }
 
-  // HIP managed variables need to be emitted as declarations in device
-  // compilation.
-  if (!IsHIPManagedVarOnDevice)
-    GV->setInitializer(Init);
+  GV->setInitializer(Init);
   if (emitter)
     emitter->finalize(GV);
 
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