1//===-- CodeGen/AsmPrinter/ARMException.cpp - ARM EHABI Exception Impl ----===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains support for writing DWARF exception info into asm files.
10//
11//===----------------------------------------------------------------------===//
12
13#include "DwarfException.h"
14#include "llvm/ADT/Twine.h"
15#include "llvm/CodeGen/AsmPrinter.h"
16#include "llvm/CodeGen/MachineFunction.h"
17#include "llvm/IR/DataLayout.h"
18#include "llvm/IR/Mangler.h"
19#include "llvm/IR/Module.h"
20#include "llvm/MC/MCAsmInfo.h"
21#include "llvm/MC/MCExpr.h"
22#include "llvm/MC/MCSection.h"
23#include "llvm/MC/MCStreamer.h"
24#include "llvm/MC/MCSymbol.h"
25#include "llvm/Support/FormattedStream.h"
26#include "llvm/Target/TargetOptions.h"
27using namespace llvm;
28
29ARMException::ARMException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {}
30
31ARMException::~ARMException() {}
32
33ARMTargetStreamer &ARMException::getTargetStreamer() {
34  MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer();
35  return static_cast<ARMTargetStreamer &>(TS);
36}
37
38void ARMException::beginFunction(const MachineFunction *MF) {
39  if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
40    getTargetStreamer().emitFnStart();
41  // See if we need call frame info.
42  AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
43  assert(MoveType != AsmPrinter::CFI_M_EH &&
44         "non-EH CFI not yet supported in prologue with EHABI lowering");
45
46  if (MoveType == AsmPrinter::CFI_M_Debug) {
47    if (!hasEmittedCFISections) {
48      if (Asm->needsOnlyDebugCFIMoves())
49        Asm->OutStreamer->emitCFISections(false, true);
50      hasEmittedCFISections = true;
51    }
52
53    shouldEmitCFI = true;
54    Asm->OutStreamer->emitCFIStartProc(false);
55  }
56}
57
58/// endFunction - Gather and emit post-function exception information.
59///
60void ARMException::endFunction(const MachineFunction *MF) {
61  ARMTargetStreamer &ATS = getTargetStreamer();
62  const Function &F = MF->getFunction();
63  const Function *Per = nullptr;
64  if (F.hasPersonalityFn())
65    Per = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
66  bool forceEmitPersonality =
67    F.hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
68    F.needsUnwindTableEntry();
69  bool shouldEmitPersonality = forceEmitPersonality ||
70    !MF->getLandingPads().empty();
71  if (!Asm->MF->getFunction().needsUnwindTableEntry() &&
72      !shouldEmitPersonality)
73    ATS.emitCantUnwind();
74  else if (shouldEmitPersonality) {
75    // Emit references to personality.
76    if (Per) {
77      MCSymbol *PerSym = Asm->getSymbol(Per);
78      Asm->OutStreamer->emitSymbolAttribute(PerSym, MCSA_Global);
79      ATS.emitPersonality(PerSym);
80    }
81
82    // Emit .handlerdata directive.
83    ATS.emitHandlerData();
84
85    // Emit actual exception table
86    emitExceptionTable();
87  }
88
89  if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
90    ATS.emitFnEnd();
91}
92
93void ARMException::emitTypeInfos(unsigned TTypeEncoding,
94                                 MCSymbol *TTBaseLabel) {
95  const MachineFunction *MF = Asm->MF;
96  const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
97  const std::vector<unsigned> &FilterIds = MF->getFilterIds();
98
99  bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
100
101  int Entry = 0;
102  // Emit the Catch TypeInfos.
103  if (VerboseAsm && !TypeInfos.empty()) {
104    Asm->OutStreamer->AddComment(">> Catch TypeInfos <<");
105    Asm->OutStreamer->AddBlankLine();
106    Entry = TypeInfos.size();
107  }
108
109  for (const GlobalValue *GV : reverse(TypeInfos)) {
110    if (VerboseAsm)
111      Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--));
112    Asm->emitTTypeReference(GV, TTypeEncoding);
113  }
114
115  Asm->OutStreamer->emitLabel(TTBaseLabel);
116
117  // Emit the Exception Specifications.
118  if (VerboseAsm && !FilterIds.empty()) {
119    Asm->OutStreamer->AddComment(">> Filter TypeInfos <<");
120    Asm->OutStreamer->AddBlankLine();
121    Entry = 0;
122  }
123  for (std::vector<unsigned>::const_iterator
124         I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
125    unsigned TypeID = *I;
126    if (VerboseAsm) {
127      --Entry;
128      if (TypeID != 0)
129        Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry));
130    }
131
132    Asm->emitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]),
133                            TTypeEncoding);
134  }
135}
136