Implement target(branch-protection) attribute for AArch64
This patch implements `__attribute__((target("branch-protection=...")))`
in a manner, compatible with the analogous GCC feature:
https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/AArch64-Function-Attributes.html#AArch64-Function-Attributes
Differential Revision: https://reviews.llvm.org/D68711
diff --git a/clang/lib/Basic/Targets/AArch64.cpp b/clang/lib/Basic/Targets/AArch64.cpp
index bdfb570..5214f7c 100644
--- a/clang/lib/Basic/Targets/AArch64.cpp
+++ b/clang/lib/Basic/Targets/AArch64.cpp
@@ -15,6 +15,8 @@
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/AArch64TargetParser.h"
using namespace clang;
using namespace clang::targets;
@@ -107,6 +109,28 @@
return true;
}
+bool AArch64TargetInfo::validateBranchProtection(StringRef Spec,
+ BranchProtectionInfo &BPI,
+ StringRef &Err) const {
+ llvm::AArch64::ParsedBranchProtection PBP;
+ if (!llvm::AArch64::parseBranchProtection(Spec, PBP, Err))
+ return false;
+
+ BPI.SignReturnAddr =
+ llvm::StringSwitch<CodeGenOptions::SignReturnAddressScope>(PBP.Scope)
+ .Case("non-leaf", CodeGenOptions::SignReturnAddressScope::NonLeaf)
+ .Case("all", CodeGenOptions::SignReturnAddressScope::All)
+ .Default(CodeGenOptions::SignReturnAddressScope::None);
+
+ if (PBP.Key == "a_key")
+ BPI.SignKey = CodeGenOptions::SignReturnAddressKeyValue::AKey;
+ else
+ BPI.SignKey = CodeGenOptions::SignReturnAddressKeyValue::BKey;
+
+ BPI.BranchTargetEnforcement = PBP.BranchTargetEnforcement;
+ return true;
+}
+
bool AArch64TargetInfo::isValidCPUName(StringRef Name) const {
return Name == "generic" ||
llvm::AArch64::parseCPUArch(Name) != llvm::AArch64::ArchKind::INVALID;