[clang] [Clang] Do not pass `-shared` when using `-r` for AMDGPU (PR #100760)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Joseph Huber (jhuber6)

<details>
<summary>Changes</summary>

Summary:
We can use `-r` and `--lto-emit-llvm` to get the LTO pass to optimize +
link LLVM-IR. Currently this doesn't work on AMDGPU because it always
passes `-shared` which is incompatible with `-r`. Fix that so we can use
it.


---
Full diff: https://github.com/llvm/llvm-project/pull/100760.diff


2 Files Affected:

- (modified) clang/lib/Driver/ToolChains/AMDGPU.cpp (+4-2) 
- (modified) clang/test/Driver/amdgpu-toolchain.c (+4) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/AMDGPU.cpp b/clang/lib/Driver/ToolChains/AMDGPU.cpp
index f6c7300162b9e..f796c31af8f67 100644
--- a/clang/lib/Driver/ToolChains/AMDGPU.cpp
+++ b/clang/lib/Driver/ToolChains/AMDGPU.cpp
@@ -620,8 +620,10 @@ void amdgpu::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                   const char *LinkingOutput) const {
   std::string Linker = getToolChain().GetLinkerPath();
   ArgStringList CmdArgs;
-  CmdArgs.push_back("--no-undefined");
-  CmdArgs.push_back("-shared");
+  if (!Args.hasArg(options::OPT_r)) {
+    CmdArgs.push_back("--no-undefined");
+    CmdArgs.push_back("-shared");
+  }
 
   addLinkerCompressDebugSectionsOption(getToolChain(), Args, CmdArgs);
   Args.AddAllArgs(CmdArgs, options::OPT_L);
diff --git a/clang/test/Driver/amdgpu-toolchain.c b/clang/test/Driver/amdgpu-toolchain.c
index 8ab6a07131474..ebd1158b63074 100644
--- a/clang/test/Driver/amdgpu-toolchain.c
+++ b/clang/test/Driver/amdgpu-toolchain.c
@@ -28,3 +28,7 @@
 // RUN: %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx906 -nogpulib \
 // RUN:   -fuse-ld=ld %s 2>&1 | FileCheck -check-prefixes=LD %s
 // LD: ld.lld
+
+// RUN: %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx906 -nogpulib \
+// RUN:   -r %s 2>&1 | FileCheck -check-prefixes=RELO %s
+// RELO-NOT: -shared

``````````

</details>


https://github.com/llvm/llvm-project/pull/100760