llvm-for-llvmta/lib/MC/MCAsmInfoDarwin.cpp

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2022-04-25 10:02:23 +02:00
//===- MCAsmInfoDarwin.cpp - Darwin asm properties ------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file defines target asm properties related what form asm statements
// should take in general on Darwin-based targets
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCAsmInfoDarwin.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCSectionMachO.h"
using namespace llvm;
bool MCAsmInfoDarwin::isSectionAtomizableBySymbols(
const MCSection &Section) const {
const MCSectionMachO &SMO = static_cast<const MCSectionMachO &>(Section);
// Sections holding 1 byte strings are atomized based on the data they
// contain.
// Sections holding 2 byte strings require symbols in order to be atomized.
// There is no dedicated section for 4 byte strings.
if (SMO.getType() == MachO::S_CSTRING_LITERALS)
return false;
if (SMO.getSegmentName() == "__DATA" && SMO.getName() == "__cfstring")
return false;
if (SMO.getSegmentName() == "__DATA" && SMO.getName() == "__objc_classrefs")
return false;
switch (SMO.getType()) {
default:
return true;
// These sections are atomized at the element boundaries without using
// symbols.
case MachO::S_4BYTE_LITERALS:
case MachO::S_8BYTE_LITERALS:
case MachO::S_16BYTE_LITERALS:
case MachO::S_LITERAL_POINTERS:
case MachO::S_NON_LAZY_SYMBOL_POINTERS:
case MachO::S_LAZY_SYMBOL_POINTERS:
case MachO::S_THREAD_LOCAL_VARIABLE_POINTERS:
case MachO::S_MOD_INIT_FUNC_POINTERS:
case MachO::S_MOD_TERM_FUNC_POINTERS:
case MachO::S_INTERPOSING:
return false;
}
}
MCAsmInfoDarwin::MCAsmInfoDarwin() {
// Common settings for all Darwin targets.
// Syntax:
LinkerPrivateGlobalPrefix = "l";
HasSingleParameterDotFile = false;
HasSubsectionsViaSymbols = true;
AlignmentIsInBytes = false;
COMMDirectiveAlignmentIsInBytes = false;
LCOMMDirectiveAlignmentType = LCOMM::Log2Alignment;
InlineAsmStart = " InlineAsm Start";
InlineAsmEnd = " InlineAsm End";
// Directives:
HasWeakDefDirective = true;
HasWeakDefCanBeHiddenDirective = true;
WeakRefDirective = "\t.weak_reference ";
ZeroDirective = "\t.space\t"; // ".space N" emits N zeros.
HasMachoZeroFillDirective = true; // Uses .zerofill
HasMachoTBSSDirective = true; // Uses .tbss
// FIXME: Change this once MC is the system assembler.
HasAggressiveSymbolFolding = false;
HiddenVisibilityAttr = MCSA_PrivateExtern;
HiddenDeclarationVisibilityAttr = MCSA_Invalid;
// Doesn't support protected visibility.
ProtectedVisibilityAttr = MCSA_Invalid;
HasDotTypeDotSizeDirective = false;
HasNoDeadStrip = true;
HasAltEntry = true;
DwarfUsesRelocationsAcrossSections = false;
SetDirectiveSuppressesReloc = true;
}