ARMException.cpp revision 320296a4cfe414ce59f406b8a5ce15272f563103 
1//===-- CodeGen/AsmPrinter/ARMException.cpp - ARM EHABI Exception Impl ----===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains support for writing DWARF exception info into asm files.
11//
12//===----------------------------------------------------------------------===//
13
14#include "DwarfException.h"
15#include "llvm/ADT/SmallString.h"
16#include "llvm/ADT/StringExtras.h"
17#include "llvm/ADT/Twine.h"
18#include "llvm/CodeGen/AsmPrinter.h"
19#include "llvm/CodeGen/MachineFrameInfo.h"
20#include "llvm/CodeGen/MachineFunction.h"
21#include "llvm/CodeGen/MachineModuleInfo.h"
22#include "llvm/IR/DataLayout.h"
23#include "llvm/IR/Module.h"
24#include "llvm/MC/MCAsmInfo.h"
25#include "llvm/MC/MCContext.h"
26#include "llvm/MC/MCExpr.h"
27#include "llvm/MC/MCSection.h"
28#include "llvm/MC/MCStreamer.h"
29#include "llvm/MC/MCSymbol.h"
30#include "llvm/Support/CommandLine.h"
31#include "llvm/Support/Dwarf.h"
32#include "llvm/Support/FormattedStream.h"
33#include "llvm/Target/Mangler.h"
34#include "llvm/Target/TargetFrameLowering.h"
35#include "llvm/Target/TargetOptions.h"
36#include "llvm/Target/TargetRegisterInfo.h"
37using namespace llvm;
38
39static cl::opt<bool>
40EnableARMEHABIDescriptors("arm-enable-ehabi-descriptors", cl::Hidden,
41  cl::desc("Generate ARM EHABI tables with unwinding descriptors"),
42  cl::init(false));
43
44
45ARMException::ARMException(AsmPrinter *A)
46  : DwarfException(A) {}
47
48ARMException::~ARMException() {}
49
50ARMTargetStreamer &ARMException::getTargetStreamer() {
51  MCTargetStreamer &TS = Asm->OutStreamer.getTargetStreamer();
52  return static_cast<ARMTargetStreamer &>(TS);
53}
54
55void ARMException::EndModule() {
56}
57
58/// BeginFunction - Gather pre-function exception information. Assumes it's
59/// being emitted immediately after the function entry point.
60void ARMException::BeginFunction(const MachineFunction *MF) {
61  getTargetStreamer().emitFnStart();
62  if (Asm->MF->getFunction()->needsUnwindTableEntry())
63    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
64                                                  Asm->getFunctionNumber()));
65}
66
67/// EndFunction - Gather and emit post-function exception information.
68///
69void ARMException::EndFunction() {
70  ARMTargetStreamer &ATS = getTargetStreamer();
71  if (!Asm->MF->getFunction()->needsUnwindTableEntry())
72    ATS.emitCantUnwind();
73  else {
74    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
75                                                  Asm->getFunctionNumber()));
76
77    if (EnableARMEHABIDescriptors) {
78      // Map all labels and get rid of any dead landing pads.
79      MMI->TidyLandingPads();
80
81      if (!MMI->getLandingPads().empty()) {
82        // Emit references to personality.
83        if (const Function * Personality =
84            MMI->getPersonalities()[MMI->getPersonalityIndex()]) {
85          MCSymbol *PerSym = Asm->Mang->getSymbol(Personality);
86          Asm->OutStreamer.EmitSymbolAttribute(PerSym, MCSA_Global);
87          ATS.emitPersonality(PerSym);
88        }
89
90        // Emit .handlerdata directive.
91        ATS.emitHandlerData();
92
93        // Emit actual exception table
94        EmitExceptionTable();
95      }
96    }
97  }
98
99  ATS.emitFnEnd();
100}
101
102void ARMException::EmitTypeInfos(unsigned TTypeEncoding) {
103  const std::vector<const GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
104  const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
105
106  bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
107
108  int Entry = 0;
109  // Emit the Catch TypeInfos.
110  if (VerboseAsm && !TypeInfos.empty()) {
111    Asm->OutStreamer.AddComment(">> Catch TypeInfos <<");
112    Asm->OutStreamer.AddBlankLine();
113    Entry = TypeInfos.size();
114  }
115
116  for (std::vector<const GlobalVariable *>::const_reverse_iterator
117         I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
118    const GlobalVariable *GV = *I;
119    if (VerboseAsm)
120      Asm->OutStreamer.AddComment("TypeInfo " + Twine(Entry--));
121    Asm->EmitTTypeReference(GV, TTypeEncoding);
122  }
123
124  // Emit the Exception Specifications.
125  if (VerboseAsm && !FilterIds.empty()) {
126    Asm->OutStreamer.AddComment(">> Filter TypeInfos <<");
127    Asm->OutStreamer.AddBlankLine();
128    Entry = 0;
129  }
130  for (std::vector<unsigned>::const_iterator
131         I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
132    unsigned TypeID = *I;
133    if (VerboseAsm) {
134      --Entry;
135      if (TypeID != 0)
136        Asm->OutStreamer.AddComment("FilterInfo " + Twine(Entry));
137    }
138
139    Asm->EmitTTypeReference((TypeID == 0 ? 0 : TypeInfos[TypeID - 1]),
140                            TTypeEncoding);
141  }
142}
143