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//===- lib/MC/MCWinEH.cpp - Windows EH implementation ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/StringRef.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCWinEH.h"
#include "llvm/Support/COFF.h"
namespace llvm {
namespace WinEH {
/// We can't have one section for all .pdata or .xdata because the Microsoft
/// linker seems to want all code relocations to refer to the same object file
/// section. If the code described is comdat, create a new comdat section
/// associated with that comdat. If the code described is not in the main .text
/// section, make a new section for it. Otherwise use the main unwind info
/// section.
static const MCSection *getUnwindInfoSection(
StringRef SecName, const MCSectionCOFF *UnwindSec, const MCSymbol *Function,
MCContext &Context) {
if (Function && Function->isInSection()) {
// If Function is in a COMDAT, get or create an unwind info section in that
// COMDAT group.
const MCSectionCOFF *FunctionSection =
cast<MCSectionCOFF>(&Function->getSection());
if (FunctionSection->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT) {
return Context.getAssociativeCOFFSection(
UnwindSec, FunctionSection->getCOMDATSymbol());
}
// If Function is in a section other than .text, create a new .pdata section.
// Otherwise use the plain .pdata section.
if (const auto *Section = dyn_cast<MCSectionCOFF>(FunctionSection)) {
StringRef CodeSecName = Section->getSectionName();
if (CodeSecName == ".text")
return UnwindSec;
if (CodeSecName.startswith(".text$"))
CodeSecName = CodeSecName.substr(6);
return Context.getCOFFSection(
(SecName + Twine('$') + CodeSecName).str(),
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
SectionKind::getDataRel());
}
}
return UnwindSec;
}
const MCSection *UnwindEmitter::getPDataSection(const MCSymbol *Function,
MCContext &Context) {
const MCSectionCOFF *PData =
cast<MCSectionCOFF>(Context.getObjectFileInfo()->getPDataSection());
return getUnwindInfoSection(".pdata", PData, Function, Context);
}
const MCSection *UnwindEmitter::getXDataSection(const MCSymbol *Function,
MCContext &Context) {
const MCSectionCOFF *XData =
cast<MCSectionCOFF>(Context.getObjectFileInfo()->getXDataSection());
return getUnwindInfoSection(".xdata", XData, Function, Context);
}
}
}
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