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//===-- CodeGen/AsmPrinter/AIXException.cpp - AIX Exception Impl ----------===//
//
// 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 contains support for writing AIX exception info into asm files.
//
//===----------------------------------------------------------------------===//
#include "DwarfException.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/MC/MCSectionXCOFF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
namespace llvm {
AIXException::AIXException(AsmPrinter *A) : EHStreamer(A) {}
void AIXException::emitExceptionInfoTable(const MCSymbol *LSDA,
const MCSymbol *PerSym) {
// Generate EH Info Table.
// The EH Info Table, aka, 'compat unwind section' on AIX, have the following
// format: struct eh_info_t {
// unsigned version; /* EH info verion 0 */
// #if defined(__64BIT__)
// char _pad[4]; /* padding */
// #endif
// unsigned long lsda; /* Pointer to LSDA */
// unsigned long personality; /* Pointer to the personality routine */
// }
auto *EHInfo =
cast<MCSectionXCOFF>(Asm->getObjFileLowering().getCompactUnwindSection());
if (Asm->TM.getFunctionSections()) {
// If option -ffunction-sections is on, append the function name to the
// name of EH Info Table csect so that each function has its own EH Info
// Table csect. This helps the linker to garbage-collect EH info of unused
// functions.
SmallString<128> NameStr = EHInfo->getName();
raw_svector_ostream(NameStr) << '.' << Asm->MF->getFunction().getName();
EHInfo = Asm->OutContext.getXCOFFSection(NameStr, EHInfo->getKind(),
EHInfo->getCsectProp());
}
Asm->OutStreamer->switchSection(EHInfo);
MCSymbol *EHInfoLabel =
TargetLoweringObjectFileXCOFF::getEHInfoTableSymbol(Asm->MF);
Asm->OutStreamer->emitLabel(EHInfoLabel);
// Version number.
Asm->emitInt32(0);
const DataLayout &DL = MMI->getModule()->getDataLayout();
const unsigned PointerSize = DL.getPointerSize();
// Add necessary paddings in 64 bit mode.
Asm->OutStreamer->emitValueToAlignment(Align(PointerSize));
// LSDA location.
Asm->OutStreamer->emitValue(MCSymbolRefExpr::create(LSDA, Asm->OutContext),
PointerSize);
// Personality routine.
Asm->OutStreamer->emitValue(MCSymbolRefExpr::create(PerSym, Asm->OutContext),
PointerSize);
}
void AIXException::endFunction(const MachineFunction *MF) {
// There is no easy way to access register information in `AIXException`
// class. when ShouldEmitEHBlock is false and VRs are saved, A dumy eh info
// table are emitted in PPCAIXAsmPrinter::emitFunctionBodyEnd.
if (!TargetLoweringObjectFileXCOFF::ShouldEmitEHBlock(MF))
return;
const MCSymbol *LSDALabel = emitExceptionTable();
const Function &F = MF->getFunction();
assert(F.hasPersonalityFn() &&
"Landingpads are presented, but no personality routine is found.");
const auto *Per =
cast<GlobalValue>(F.getPersonalityFn()->stripPointerCasts());
const MCSymbol *PerSym = Asm->TM.getSymbol(Per);
emitExceptionInfoTable(LSDALabel, PerSym);
}
} // End of namespace llvm
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