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//===-- ARMMachineFunctionInfo.cpp - ARM machine function info ------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "ARMMachineFunctionInfo.h"
#include "ARMSubtarget.h"
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")),
BranchTargetEnforcement(GetBranchTargetEnforcement(MF)) {
const auto &Subtarget = MF.getSubtarget<ARMSubtarget>();
if (Subtarget.isMClass() && Subtarget.hasV7Ops())
std::tie(SignReturnAddress, SignReturnAddressAll) =
GetSignReturnAddress(MF.getFunction());
}
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