From: Alexey Bataev <a.bataev@hotmail.com>
Date: Tue, 31 Jul 2018 16:40:15 +0000 (+0000)
Subject: [OPENMP] Prevent problems with linking of the static variables.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=158a10b989e7b9cd1e9cf137be7d3b08203d9524;p=clang

[OPENMP] Prevent problems with linking of the static variables.

No need to change the linkage, we can avoid the problem using special variable. That points to the original variable and, thus, prevent some of the optimizations that might break the compilation.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@338399 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 996b80b9c5..d50f449378 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -9535,21 +9535,6 @@ static GVALinkage basicGVALinkageForFunction(const ASTContext &Context,
   return GVA_DiscardableODR;
 }
 
-static bool isDeclareTargetToDeclaration(const Decl *VD) {
-  for (const Decl *D : VD->redecls()) {
-    if (!D->hasAttrs())
-      continue;
-    if (const auto *Attr = D->getAttr<OMPDeclareTargetDeclAttr>())
-      return Attr->getMapType() == OMPDeclareTargetDeclAttr::MT_To;
-  }
-  if (const auto *V = dyn_cast<VarDecl>(VD)) {
-    if (const VarDecl *TD = V->getTemplateInstantiationPattern())
-      return isDeclareTargetToDeclaration(TD);
-  }
-
-  return false;
-}
-
 static GVALinkage adjustGVALinkageForAttributes(const ASTContext &Context,
                                                 const Decl *D, GVALinkage L) {
   // See http://msdn.microsoft.com/en-us/library/xa0d9ste.aspx
@@ -9566,12 +9551,6 @@ static GVALinkage adjustGVALinkageForAttributes(const ASTContext &Context,
     // visible externally so they can be launched from host.
     if (L == GVA_DiscardableODR || L == GVA_Internal)
       return GVA_StrongODR;
-  } else if (Context.getLangOpts().OpenMP && Context.getLangOpts().OpenMPIsDevice &&
-             isDeclareTargetToDeclaration(D)) {
-    // Static variables must be visible externally so they can be mapped from
-    // host.
-    if (L == GVA_Internal)
-      return GVA_StrongODR;
   }
   return L;
 }
diff --git a/lib/CodeGen/CGOpenMPRuntime.cpp b/lib/CodeGen/CGOpenMPRuntime.cpp
index 3730b9af12..060f2ea8f5 100644
--- a/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -8109,6 +8109,19 @@ void CGOpenMPRuntime::registerTargetGlobalVariable(const VarDecl *VD,
       VarName = CGM.getMangledName(VD);
       VarSize = CGM.getContext().getTypeSizeInChars(VD->getType());
       Linkage = CGM.getLLVMLinkageVarDefinition(VD, /*IsConstant=*/false);
+      // Temp solution to prevent optimizations of the internal variables.
+      if (CGM.getLangOpts().OpenMPIsDevice && !VD->isExternallyVisible()) {
+        std::string RefName = getName({VarName, "ref"});
+        if (!CGM.GetGlobalValue(RefName)) {
+          llvm::Constant *AddrRef =
+              getOrCreateInternalVariable(Addr->getType(), RefName);
+          auto *GVAddrRef = cast<llvm::GlobalVariable>(AddrRef);
+          GVAddrRef->setConstant(/*Val=*/true);
+          GVAddrRef->setLinkage(llvm::GlobalValue::InternalLinkage);
+          GVAddrRef->setInitializer(Addr);
+          CGM.addCompilerUsedGlobal(GVAddrRef);
+        }
+      }
       break;
     case OMPDeclareTargetDeclAttr::MT_Link:
       Flags = OffloadEntriesInfoManagerTy::OMPTargetGlobalVarEntryLink;
diff --git a/test/OpenMP/declare_target_codegen.cpp b/test/OpenMP/declare_target_codegen.cpp
index a221387c73..96bdc874ec 100644
--- a/test/OpenMP/declare_target_codegen.cpp
+++ b/test/OpenMP/declare_target_codegen.cpp
@@ -18,14 +18,15 @@
 // CHECK-DAG: @d = global i32 0,
 // CHECK-DAG: @c = external global i32,
 // CHECK-DAG: @globals = global %struct.S zeroinitializer,
-// CHECK-DAG: @{{.+}}stat = weak_odr global %struct.S zeroinitializer,
-// CHECK-DAG: @llvm.used = appending global [2 x i8*] [i8* bitcast (void ()* @__omp_offloading__{{.+}}_globals_l[[@LINE+42]]_ctor to i8*), i8* bitcast (void ()* @__omp_offloading__{{.+}}_stat_l[[@LINE+43]]_ctor to i8*)], section "llvm.metadata"
+// CHECK-DAG: [[STAT:@.+stat]] = internal global %struct.S zeroinitializer,
+// CHECK-DAG: [[STAT_REF:@.+]] = internal constant %struct.S* [[STAT]]
+// CHECK-DAG: @llvm.used = appending global [2 x i8*] [i8* bitcast (void ()* @__omp_offloading__{{.+}}_globals_l[[@LINE+42]]_ctor to i8*), i8* bitcast (void ()* @__omp_offloading__{{.+}}_stat_l[[@LINE+43]]_ctor to i8*)],
+// CHECK-DAG: @llvm.compiler.used = appending global [1 x i8*] [i8* bitcast (%struct.S** [[STAT_REF]] to i8*)],
 
 // CHECK-DAG: define {{.*}}i32 @{{.*}}{{foo|bar|baz2|baz3|FA|f_method}}{{.*}}()
 // CHECK-DAG: define {{.*}}void @{{.*}}TemplateClass{{.*}}(%class.TemplateClass* %{{.*}})
 // CHECK-DAG: define {{.*}}i32 @{{.*}}TemplateClass{{.*}}f_method{{.*}}(%class.TemplateClass* %{{.*}})
-// CHECK-DAG: define {{.*}}void @__omp_offloading__{{.*}}_globals_l[[@LINE+37]]_ctor()
-// CHECK-DAG: define {{.*}}void @__omp_offloading__{{.*}}_stat_l[[@LINE+37]]_ctor()
+// CHECK-DAG: define {{.*}}void @__omp_offloading__{{.*}}_globals_l[[@LINE+36]]_ctor()
 
 #ifndef HEADER
 #define HEADER
diff --git a/test/OpenMP/nvptx_declare_target_var_ctor_dtor_codegen.cpp b/test/OpenMP/nvptx_declare_target_var_ctor_dtor_codegen.cpp
index 3cd85eefbc..b9049a4028 100644
--- a/test/OpenMP/nvptx_declare_target_var_ctor_dtor_codegen.cpp
+++ b/test/OpenMP/nvptx_declare_target_var_ctor_dtor_codegen.cpp
@@ -15,7 +15,7 @@
 
 // SIMD-ONLY-NOT: {{__kmpc|__tgt}}
 
-// DEVICE-DAG: [[C_ADDR:.+]] = weak_odr global i32 0,
+// DEVICE-DAG: [[C_ADDR:.+]] = internal global i32 0,
 // DEVICE-DAG: [[CD_ADDR:@.+]] = global %struct.S zeroinitializer,
 // HOST-DAG: @[[C_ADDR:.+]] = internal global i32 0,
 // HOST-DAG: @[[CD_ADDR:.+]] = global %struct.S zeroinitializer,