ARMException.cpp revision d04a8d4b33ff316ca4cf961e06c9e312eff8e64f 
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/DataLayout.h"
23#include "llvm/MC/MCAsmInfo.h"
24#include "llvm/MC/MCContext.h"
25#include "llvm/MC/MCExpr.h"
26#include "llvm/MC/MCSection.h"
27#include "llvm/MC/MCStreamer.h"
28#include "llvm/MC/MCSymbol.h"
29#include "llvm/Module.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/TargetMachine.h"
36#include "llvm/Target/TargetOptions.h"
37#include "llvm/Target/TargetRegisterInfo.h"
38using namespace llvm;
39
40cl::opt<bool>
41EnableARMEHABIDescriptors("arm-enable-ehabi-descriptors", cl::Hidden,
42  cl::desc("Generate ARM EHABI tables with unwinding descriptors"),
43  cl::init(false));
44
45
46ARMException::ARMException(AsmPrinter *A)
47  : DwarfException(A) {}
48
49ARMException::~ARMException() {}
50
51void ARMException::EndModule() {
52}
53
54/// BeginFunction - Gather pre-function exception information. Assumes it's
55/// being emitted immediately after the function entry point.
56void ARMException::BeginFunction(const MachineFunction *MF) {
57  Asm->OutStreamer.EmitFnStart();
58  if (Asm->MF->getFunction()->needsUnwindTableEntry())
59    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
60                                                  Asm->getFunctionNumber()));
61}
62
63/// EndFunction - Gather and emit post-function exception information.
64///
65void ARMException::EndFunction() {
66  if (!Asm->MF->getFunction()->needsUnwindTableEntry())
67    Asm->OutStreamer.EmitCantUnwind();
68  else {
69    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
70                                                  Asm->getFunctionNumber()));
71
72    if (EnableARMEHABIDescriptors) {
73      // Map all labels and get rid of any dead landing pads.
74      MMI->TidyLandingPads();
75
76      if (!MMI->getLandingPads().empty()) {
77        // Emit references to personality.
78        if (const Function * Personality =
79            MMI->getPersonalities()[MMI->getPersonalityIndex()]) {
80          MCSymbol *PerSym = Asm->Mang->getSymbol(Personality);
81          Asm->OutStreamer.EmitSymbolAttribute(PerSym, MCSA_Global);
82          Asm->OutStreamer.EmitPersonality(PerSym);
83        }
84
85        // Emit .handlerdata directive.
86        Asm->OutStreamer.EmitHandlerData();
87
88        // Emit actual exception table
89        EmitExceptionTable();
90      }
91    }
92  }
93
94  Asm->OutStreamer.EmitFnEnd();
95}
96
97void ARMException::EmitTypeInfos(unsigned TTypeEncoding) {
98  const std::vector<const GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
99  const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
100
101  bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
102
103  int Entry = 0;
104  // Emit the Catch TypeInfos.
105  if (VerboseAsm && !TypeInfos.empty()) {
106    Asm->OutStreamer.AddComment(">> Catch TypeInfos <<");
107    Asm->OutStreamer.AddBlankLine();
108    Entry = TypeInfos.size();
109  }
110
111  for (std::vector<const GlobalVariable *>::const_reverse_iterator
112         I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
113    const GlobalVariable *GV = *I;
114    if (VerboseAsm)
115      Asm->OutStreamer.AddComment("TypeInfo " + Twine(Entry--));
116    Asm->EmitTTypeReference(GV, TTypeEncoding);
117  }
118
119  // Emit the Exception Specifications.
120  if (VerboseAsm && !FilterIds.empty()) {
121    Asm->OutStreamer.AddComment(">> Filter TypeInfos <<");
122    Asm->OutStreamer.AddBlankLine();
123    Entry = 0;
124  }
125  for (std::vector<unsigned>::const_iterator
126         I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
127    unsigned TypeID = *I;
128    if (VerboseAsm) {
129      --Entry;
130      if (TypeID != 0)
131        Asm->OutStreamer.AddComment("FilterInfo " + Twine(Entry));
132    }
133
134    Asm->EmitTTypeReference((TypeID == 0 ? 0 : TypeInfos[TypeID - 1]),
135                            TTypeEncoding);
136  }
137}
138