vendor/llvm-project/llvmorg-14-init-11187-g222442ec2d71

1 files changed, 56 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMMachineFunctionInfo.cpp b/llvm/lib/Target/ARM/ARMMachineFunctionInfo.cpp
index 507c3e69b3a4..308d5e7889f2 100644
--- a/llvm/lib/Target/ARM/ARMMachineFunctionInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMMachineFunctionInfo.cpp
@@ -13,8 +13,63 @@ using namespace llvm;
 
 void ARMFunctionInfo::anchor() {}
 
+static bool GetBranchTargetEnforcement(MachineFunction &MF) {
+  const auto &Subtarget = MF.getSubtarget<ARMSubtarget>();
+  if (!Subtarget.isMClass() || !Subtarget.hasV7Ops())
+    return false;
+
+  const Function &F = MF.getFunction();
+  if (!F.hasFnAttribute("branch-target-enforcement")) {
+    if (const auto *BTE = mdconst::extract_or_null<ConstantInt>(
+            F.getParent()->getModuleFlag("branch-target-enforcement")))
+      return BTE->getZExtValue();
+    return false;
+  }
+
+  const StringRef BTIEnable =
+      F.getFnAttribute("branch-target-enforcement").getValueAsString();
+  assert(BTIEnable.equals_insensitive("true") ||
+         BTIEnable.equals_insensitive("false"));
+  return BTIEnable.equals_insensitive("true");
+}
+
+// The pair returns values for the ARMFunctionInfo members
+// SignReturnAddress and SignReturnAddressAll respectively.
+static std::pair<bool, bool> GetSignReturnAddress(const Function &F) {
+  if (!F.hasFnAttribute("sign-return-address")) {
+    const Module &M = *F.getParent();
+    if (const auto *Sign = mdconst::extract_or_null<ConstantInt>(
+            M.getModuleFlag("sign-return-address"))) {
+      if (Sign->getZExtValue()) {
+        if (const auto *All = mdconst::extract_or_null<ConstantInt>(
+                M.getModuleFlag("sign-return-address-all")))
+          return {true, All->getZExtValue()};
+        return {true, false};
+      }
+    }
+    return {false, false};
+  }
+
+  StringRef Scope = F.getFnAttribute("sign-return-address").getValueAsString();
+  if (Scope.equals("none"))
+    return {false, false};
+
+  if (Scope.equals("all"))
+    return {true, true};
+
+  assert(Scope.equals("non-leaf"));
+  return {true, false};
+}
+
 ARMFunctionInfo::ARMFunctionInfo(MachineFunction &MF)
     : isThumb(MF.getSubtarget<ARMSubtarget>().isThumb()),
       hasThumb2(MF.getSubtarget<ARMSubtarget>().hasThumb2()),
       IsCmseNSEntry(MF.getFunction().hasFnAttribute("cmse_nonsecure_entry")),
-      IsCmseNSCall(MF.getFunction().hasFnAttribute("cmse_nonsecure_call")) {}
+      IsCmseNSCall(MF.getFunction().hasFnAttribute("cmse_nonsecure_call")),
+      BranchTargetEnforcement(GetBranchTargetEnforcement(MF)) {
+
+  const auto &Subtarget = MF.getSubtarget<ARMSubtarget>();
+  if (Subtarget.isMClass() && Subtarget.hasV7Ops())
+    std::tie(SignReturnAddress, SignReturnAddressAll) =
+        GetSignReturnAddress(MF.getFunction());
+}