[PATCH] D50596: [HIP] Make __hip_gpubin_handle hidden to avoid being merged across different shared libraries

[Yaxun Liu via Phabricator via cfe-commits]

yaxunl created this revision.
yaxunl added reviewers: rjmccall, tra.

Different shared libraries contain different fat binary, which is stored in a global variable
`__hip_gpubin_handle`. Since different compilation units share the same fat binary, this
variable has linkonce linkage. However, it should not be merged across different shared
libraries.

This patch set the visibility of the global variable to be hidden, which will make it invisible
in the shared library, therefore preventing it from being merged.


https://reviews.llvm.org/D50596

Files:
  lib/CodeGen/CGCUDANV.cpp
  test/CodeGenCUDA/device-stub.cu


Index: test/CodeGenCUDA/device-stub.cu
===================================================================
--- test/CodeGenCUDA/device-stub.cu
+++ test/CodeGenCUDA/device-stub.cu
@@ -80,7 +80,7 @@
 // HIP-SAME: section ".hipFatBinSegment"
 // * variable to save GPU binary handle after initialization
 // CUDANORDC: @__[[PREFIX]]_gpubin_handle = internal global i8** null
-// HIP: @__[[PREFIX]]_gpubin_handle = linkonce global i8** null
+// HIP: @__[[PREFIX]]_gpubin_handle = linkonce hidden global i8** null
 // * constant unnamed string with NVModuleID
 // RDC: [[MODULE_ID_GLOBAL:@.*]] = private constant
 // CUDARDC-SAME: c"[[MODULE_ID:.+]]\00", section "__nv_module_id", align 32
Index: lib/CodeGen/CGCUDANV.cpp
===================================================================
--- lib/CodeGen/CGCUDANV.cpp
+++ lib/CodeGen/CGCUDANV.cpp
@@ -459,6 +459,8 @@
         /*Initializer=*/llvm::ConstantPointerNull::get(VoidPtrPtrTy),
         "__hip_gpubin_handle");
     GpuBinaryHandle->setAlignment(CGM.getPointerAlign().getQuantity());
+    // Prevent the weak symbol in different shared libraries being merged.
+    GpuBinaryHandle->setVisibility(llvm::GlobalValue::HiddenVisibility);
     Address GpuBinaryAddr(
         GpuBinaryHandle,
         CharUnits::fromQuantity(GpuBinaryHandle->getAlignment()));


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