[PATCH] D122352: [OpenMP] Do not create offloading entries for internal or hidden symbols

[Joseph Huber via Phabricator via cfe-commits]

jhuber6 created this revision.
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Currently we create offloading entries to register device variables with
the host. When we register a variable we will look up the symbol in the
device image and map the device address to the host address. This is a
problem when the symbol is declared with hidden visibility or internal
linkage. This means the symbol is not accessible externally and we
cannot get its address. We should still allow static variables to be
declared on the device, but ew should not create an offloading entry for
them so they exist independently on the host and device.

Fixes #54309


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D122352

Files:
  clang/lib/CodeGen/CGOpenMPRuntime.cpp
  clang/test/OpenMP/nvptx_declare_target_var_ctor_dtor_codegen.cpp


Index: clang/test/OpenMP/nvptx_declare_target_var_ctor_dtor_codegen.cpp
===================================================================
--- clang/test/OpenMP/nvptx_declare_target_var_ctor_dtor_codegen.cpp
+++ clang/test/OpenMP/nvptx_declare_target_var_ctor_dtor_codegen.cpp
@@ -72,8 +72,6 @@
 // DEVICE-DAG: call void
 // DEVICE-DAG: ret void
 
-// HOST-DAG: @.omp_offloading.entry_name{{.*}} = internal unnamed_addr constant [{{[0-9]+}} x i8] c"[[C_ADDR]]\00"
-// HOST-DAG: @.omp_offloading.entry.[[C_ADDR]] = weak{{.*}} constant %struct.__tgt_offload_entry { i8* bitcast (i32* @[[C_ADDR]] to i8*), i8* getelementptr inbounds ([{{[0-9]+}} x i8], [{{[0-9]+}} x i8]* @.omp_offloading.entry_name{{.*}}, i32 0, i32 0), i64 4, i32 0, i32 0 }, section "omp_offloading_entries", align 1
 // HOST-DAG: @.omp_offloading.entry_name{{.*}} = internal unnamed_addr constant [{{[0-9]+}} x i8] c"[[CD_ADDR]]\00"
 // HOST-DAG: @.omp_offloading.entry.[[CD_ADDR]] = weak{{.*}} constant %struct.__tgt_offload_entry { i8* bitcast (%struct.S* @[[CD_ADDR]] to i8*), i8* getelementptr inbounds ([{{[0-9]+}} x i8], [{{[0-9]+}} x i8]* @.omp_offloading.entry_name{{.*}}, i32 0, i32 0), i64 4, i32 0, i32 0 }, section "omp_offloading_entries", align 1
 // HOST-DAG: @.omp_offloading.entry_name{{.*}} = internal unnamed_addr constant [{{[0-9]+}} x i8] c"[[C_CTOR]]\00"
Index: clang/lib/CodeGen/CGOpenMPRuntime.cpp
===================================================================
--- clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -3323,6 +3323,15 @@
         }
         break;
       }
+
+      // Hidden or internal symbols on the device are not externally visible. We
+      // should not attempt to register them by creating an offloading entry.
+      if (auto *GV = dyn_cast<llvm::GlobalValue>(CE->getAddress()))
+        if (GV->getLinkage() == llvm::GlobalValue::InternalLinkage ||
+            GV->getLinkage() == llvm::GlobalValue::PrivateLinkage ||
+            GV->getVisibility() == llvm::GlobalValue::HiddenVisibility)
+          continue;
+
       createOffloadEntry(CE->getAddress(), CE->getAddress(),
                          CE->getVarSize().getQuantity(), Flags,
                          CE->getLinkage());


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