[llvm] [clang] [AArch64] Stack probing for function prologues (PR #66524)

[Momchil Velikov via cfe-commits]

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@@ -1076,6 +1076,16 @@ void CodeGenModule::Release() {
                                 "sign-return-address-with-bkey", 1);
   }
 
+  if (Arch == llvm::Triple::aarch64 || Arch == llvm::Triple::aarch64_be) {
+    auto *InlineAsm = llvm::MDString::get(TheModule.getContext(), "inline-asm");
+    if (CodeGenOpts.StackClashProtector)
+      getModule().addModuleFlag(llvm::Module::Override, "probe-stack",
+                                InlineAsm);
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momchil-velikov wrote:

We would like to use a module flag so the stack clash protection is effective for functions created by LLVM (e..g `asan.module_ctor`).
It is not AArch64 specific in principle, but other backends which implement SCP still rely on function attributes. When/if other backends adopt this approach the condition can be removed.
@serge-sans-paille 

https://github.com/llvm/llvm-project/pull/66524