[clang] [Driver][HIP/SPIRV] Fix crash when llvm-link is executed. (PR #196074)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Manuel Carrasco (mgcarrasco)

<details>
<summary>Changes</summary>

There is a design limitation (see [InputInfo](https://github.com/llvm/llvm-project/blob/f08b4fff52cdd3fc8fdd962080da089497c00fcc/clang/include/clang/Driver/InputInfo.h#L23)) that is forwarding flags to `llvm-link` when it shouldn't happen. This commit fixes this issue by sanitizing the arguments forwarded to `llvm-link`.

This may happen when `clang-linker-wrapper` eventually calls `clang`, which adds the `-Xlinker` flags. Crash reproducer is here: https://gcc.godbolt.org/z/rxvWcvan3.

The fix is based on @<!-- -->MrSidims' old PR (#<!-- -->183492).

The error started manifesting by default after the switch to the new driver, and the issue has been in the new driver since commit https://github.com/llvm/llvm-project/commit/4c6f398b866030c17fd94dcdca04f4df03c5214c. However, the problem could potentially be triggered by any call to `clang`, regardless of the `clang-linker-wrapper`. 

---
Full diff: https://github.com/llvm/llvm-project/pull/196074.diff


2 Files Affected:

- (modified) clang/lib/Driver/ToolChains/HIPAMD.cpp (+5-2) 
- (added) clang/test/Driver/hip-spirv-linker-crash.c (+16) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/HIPAMD.cpp b/clang/lib/Driver/ToolChains/HIPAMD.cpp
index b4ff90c1d61f0..2eca149bbc998 100644
--- a/clang/lib/Driver/ToolChains/HIPAMD.cpp
+++ b/clang/lib/Driver/ToolChains/HIPAMD.cpp
@@ -39,8 +39,11 @@ void AMDGCN::Linker::constructLLVMLinkCommand(
 
   ArgStringList LinkerInputs;
 
-  for (auto Input : Inputs)
-    LinkerInputs.push_back(Input.getFilename());
+  for (auto Input : Inputs) {
+    if (Input.isFilename()) {
+      LinkerInputs.push_back(Input.getFilename());
+    }
+  }
 
   // Look for archive of bundled bitcode in arguments, and add temporary files
   // for the extracted archive of bitcode to inputs.
diff --git a/clang/test/Driver/hip-spirv-linker-crash.c b/clang/test/Driver/hip-spirv-linker-crash.c
new file mode 100644
index 0000000000000..d674d9ddec36c
--- /dev/null
+++ b/clang/test/Driver/hip-spirv-linker-crash.c
@@ -0,0 +1,16 @@
+// Verify that SPIR-V compilation does not crash during the llvm-link step
+// due to extra args that are not meant to be forwarded there.
+//
+// RUN: %clang -### --target=spirv64-amd-amdhsa -use-spirv-backend \
+// RUN:   -Xlinker -opt-bisect-limit=-1 %s 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-LINKER-OPT
+//
+// RUN: %clang -### --target=spirv64-amd-amdhsa -use-spirv-backend \
+// RUN:   -Xlinker -mllvm -Xlinker -opt-bisect-limit=-1 %s 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-LINKER-MLLVM
+//
+// CHECK-LINKER-OPT: "{{.*}}llvm-link"
+// CHECK-LINKER-OPT-SAME: "-o" "{{.*}}" "{{.*}}"{{$}}
+//
+// CHECK-LINKER-MLLVM: "{{.*}}llvm-link"
+// CHECK-LINKER-MLLVM-SAME: "-o" "{{.*}}" "{{.*}}"{{$}}

``````````

</details>


https://github.com/llvm/llvm-project/pull/196074