[clang] [HIP] fix stack marking for -fgpu-rdc (PR #72782)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-driver

Author: Yaxun (Sam) Liu (yxsamliu)

<details>
<summary>Changes</summary>

HIP toolchain uses llvm-mc to generate a host object embedding device binary for -fgpu-rdc. Due to lack of .note.GNU-stack section, the generated relocatable has executable stack marking, which disables protection from executable stack for any HIP programs compiled with -fgpu-rdc.

This patch adds .note.GNU-stack section to the input to llvm-mc to fix the executable stack marking.

Fixes: https://github.com/llvm/llvm-project/issues/71711

---
Full diff: https://github.com/llvm/llvm-project/pull/72782.diff


2 Files Affected:

- (modified) clang/lib/Driver/ToolChains/HIPUtility.cpp (+2) 
- (modified) clang/test/Driver/hip-toolchain-rdc.hip (+2) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/HIPUtility.cpp b/clang/lib/Driver/ToolChains/HIPUtility.cpp
index 04efdcba20ea740..671cd060e0d810d 100644
--- a/clang/lib/Driver/ToolChains/HIPUtility.cpp
+++ b/clang/lib/Driver/ToolChains/HIPUtility.cpp
@@ -150,6 +150,8 @@ void HIP::constructGenerateObjFileFromHIPFatBinary(
   ObjStream << "  .incbin ";
   llvm::sys::printArg(ObjStream, BundleFile, /*Quote=*/true);
   ObjStream << "\n";
+  if (HostTriple.isOSLinux() && HostTriple.isOSBinFormatELF())
+	  ObjStream << "  .section .note.GNU-stack, \"\", @progbits\n";
   ObjStream.flush();
 
   // Dump the contents of the temp object file gen if the user requested that.
diff --git a/clang/test/Driver/hip-toolchain-rdc.hip b/clang/test/Driver/hip-toolchain-rdc.hip
index fa30bb8a9f5f576..1827531f9cab7a3 100644
--- a/clang/test/Driver/hip-toolchain-rdc.hip
+++ b/clang/test/Driver/hip-toolchain-rdc.hip
@@ -32,6 +32,8 @@
 // CHECK: .p2align 12
 // CHECK: __hip_fatbin:
 // CHECK: .incbin "[[BUNDLE:.*hipfb]]"
+// LNX: .section .note.GNU-stack, "", @progbits
+// MSVC-NOT: .note.GNU-stack
 
 // emit objects for host side path
 // CHECK: [[CLANG:".*clang.*"]] "-cc1" "-triple" [[HOST:"x86_64-[^"]+"]]

``````````

</details>


https://github.com/llvm/llvm-project/pull/72782