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//=- AArch64MachineFunctionInfo.cpp - AArch64 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file implements AArch64-specific per-machine-function
/// information.
///
//===----------------------------------------------------------------------===//
#include "AArch64MachineFunctionInfo.h"
#include "AArch64InstrInfo.h"
#include <llvm/IR/Metadata.h>
#include <llvm/IR/Module.h>
using namespace llvm;
yaml::AArch64FunctionInfo::AArch64FunctionInfo(
const llvm::AArch64FunctionInfo &MFI)
: HasRedZone(MFI.hasRedZone()) {}
void yaml::AArch64FunctionInfo::mappingImpl(yaml::IO &YamlIO) {
MappingTraits<AArch64FunctionInfo>::mapping(YamlIO, *this);
}
void AArch64FunctionInfo::initializeBaseYamlFields(
const yaml::AArch64FunctionInfo &YamlMFI) {
if (YamlMFI.HasRedZone.hasValue())
HasRedZone = YamlMFI.HasRedZone;
}
static std::pair<bool, bool> GetSignReturnAddress(const Function &F) {
// The function should be signed in the following situations:
// - sign-return-address=all
// - sign-return-address=non-leaf and the functions spills the LR
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};
}
static bool ShouldSignWithBKey(const Function &F) {
if (!F.hasFnAttribute("sign-return-address-key")) {
if (const auto *BKey = mdconst::extract_or_null<ConstantInt>(
F.getParent()->getModuleFlag("sign-return-address-with-bkey")))
return BKey->getZExtValue();
return false;
}
const StringRef Key =
F.getFnAttribute("sign-return-address-key").getValueAsString();
assert(Key.equals_lower("a_key") || Key.equals_lower("b_key"));
return Key.equals_lower("b_key");
}
AArch64FunctionInfo::AArch64FunctionInfo(MachineFunction &MF) : MF(MF) {
// If we already know that the function doesn't have a redzone, set
// HasRedZone here.
if (MF.getFunction().hasFnAttribute(Attribute::NoRedZone))
HasRedZone = false;
const Function &F = MF.getFunction();
std::tie(SignReturnAddress, SignReturnAddressAll) = GetSignReturnAddress(F);
SignWithBKey = ShouldSignWithBKey(F);
if (!F.hasFnAttribute("branch-target-enforcement")) {
if (const auto *BTE = mdconst::extract_or_null<ConstantInt>(
F.getParent()->getModuleFlag("branch-target-enforcement")))
BranchTargetEnforcement = BTE->getZExtValue();
return;
}
const StringRef BTIEnable = F.getFnAttribute("branch-target-enforcement").getValueAsString();
assert(BTIEnable.equals_lower("true") || BTIEnable.equals_lower("false"));
BranchTargetEnforcement = BTIEnable.equals_lower("true");
}
bool AArch64FunctionInfo::shouldSignReturnAddress(bool SpillsLR) const {
if (!SignReturnAddress)
return false;
if (SignReturnAddressAll)
return true;
return SpillsLR;
}
bool AArch64FunctionInfo::shouldSignReturnAddress() const {
return shouldSignReturnAddress(llvm::any_of(
MF.getFrameInfo().getCalleeSavedInfo(),
[](const auto &Info) { return Info.getReg() == AArch64::LR; }));
}
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