[llvm-branch-commits] [clang] release/23.x: [clang][KCFI] Skip the KCFIPass on Hexagon (#211716) (PR #216583)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-codegen

Author: llvmbot

<details>
<summary>Changes</summary>

Backport 23a601dc9690

Requested by: @<!-- -->androm3da

---
Full diff: https://github.com/llvm/llvm-project/pull/216583.diff


2 Files Affected:

- (modified) clang/lib/CodeGen/BackendUtil.cpp (+2-1) 
- (added) clang/test/CodeGen/kcfi-hexagon.c (+14) 


``````````diff
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 2b755fa916e55..e3ae446fbe81b 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -668,7 +668,8 @@ static void addKCFIPass(const Triple &TargetTriple, const LangOptions &LangOpts,
   // If the back-end supports KCFI operand bundle lowering, skip KCFIPass.
   if (TargetTriple.getArch() == llvm::Triple::x86_64 ||
       TargetTriple.isAArch64(64) || TargetTriple.isRISCV() ||
-      TargetTriple.isARM() || TargetTriple.isThumb())
+      TargetTriple.isARM() || TargetTriple.isThumb() ||
+      TargetTriple.getArch() == llvm::Triple::hexagon)
     return;
 
   // Ensure we lower KCFI operand bundles with -O0.
diff --git a/clang/test/CodeGen/kcfi-hexagon.c b/clang/test/CodeGen/kcfi-hexagon.c
new file mode 100644
index 0000000000000..b08758d4b81a4
--- /dev/null
+++ b/clang/test/CodeGen/kcfi-hexagon.c
@@ -0,0 +1,14 @@
+// Hexagon lowers KCFI operand bundles in the back end. Clang must leave the "kcfi"
+// operand bundles in place for the back end instead of running the middle-end
+// KCFIPass, which would rewrite them into a software llvm.debugtrap check.
+//
+// Verify the bundle survives the optimizer pipeline at both -O0 and -O2 and
+// is not lowered to debugtrap.
+//
+// RUN: %clang_cc1 -triple hexagon-unknown-linux-musl -O0 -fsanitize=kcfi -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple hexagon-unknown-linux-musl -O2 -fsanitize=kcfi -emit-llvm -o - %s | FileCheck %s
+
+// CHECK-LABEL: define {{.*}}void @call(
+// CHECK: call void %{{.*}}() {{.*}}[ "kcfi"(i32 {{-?[0-9]+}}) ]
+// CHECK-NOT: @llvm.debugtrap
+void call(void (*f)(void)) { f(); }

``````````

</details>


https://github.com/llvm/llvm-project/pull/216583