From 90b8bc003caacd165dedbb9cafc32de10d610ea7 Mon Sep 17 00:00:00 2001
From: Peter Collingbourne <peter@pcc.me.uk>
Date: Mon, 25 Nov 2019 12:28:11 -0800
Subject: [PATCH] IRGen: Call SetLLVMFunctionAttributes{,ForDefinition} on
 __cfi_check_fail.

This has the main effect of causing target-cpu and target-features to be set
on __cfi_check_fail, causing the function to become ABI-compatible with other
functions in the case where these attributes affect ABI (e.g. reserve-x18).

Technically we only need to call SetLLVMFunctionAttributes to get the target-*
attributes set, but since we're creating a definition we probably ought to
call the ForDefinition function as well.

Fixes PR44094.

Differential Revision: https://reviews.llvm.org/D70692
---
 clang/lib/CodeGen/CGExpr.cpp              | 3 +++
 clang/test/CodeGen/cfi-check-fail-attrs.c | 5 +++++
 2 files changed, 8 insertions(+)
 create mode 100644 clang/test/CodeGen/cfi-check-fail-attrs.c

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 214378a966f0..04c6504910b8 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -3200,6 +3200,9 @@ void CodeGenFunction::EmitCfiCheckFail() {
   llvm::Function *F = llvm::Function::Create(
       llvm::FunctionType::get(VoidTy, {VoidPtrTy, VoidPtrTy}, false),
       llvm::GlobalValue::WeakODRLinkage, "__cfi_check_fail", &CGM.getModule());
+
+  CGM.SetLLVMFunctionAttributes(GlobalDecl(), FI, F);
+  CGM.SetLLVMFunctionAttributesForDefinition(nullptr, F);
   F->setVisibility(llvm::GlobalValue::HiddenVisibility);
 
   StartFunction(GlobalDecl(), CGM.getContext().VoidTy, F, FI, Args,
diff --git a/clang/test/CodeGen/cfi-check-fail-attrs.c b/clang/test/CodeGen/cfi-check-fail-attrs.c
new file mode 100644
index 000000000000..77ba29a5581c
--- /dev/null
+++ b/clang/test/CodeGen/cfi-check-fail-attrs.c
@@ -0,0 +1,5 @@
+// RUN: %clang_cc1 -triple aarch64-unknown-linux -fsanitize-cfi-cross-dso -target-feature +reserve-x18 -emit-llvm -o - %s | FileCheck %s
+
+// CHECK: define weak_odr hidden void @__cfi_check_fail{{.*}} [[ATTR:#[0-9]*]]
+
+// CHECK: attributes [[ATTR]] = {{.*}} "target-features"="+reserve-x18"