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/Mangler.h"
24 #include "llvm/IR/Module.h"
25 #include "llvm/MC/MCAsmInfo.h"
26 #include "llvm/MC/MCContext.h"
27 #include "llvm/MC/MCExpr.h"
28 #include "llvm/MC/MCSection.h"
29 #include "llvm/MC/MCStreamer.h"
30 #include "llvm/MC/MCSymbol.h"
31 #include "llvm/Support/CommandLine.h"
32 #include "llvm/Support/Dwarf.h"
33 #include "llvm/Support/FormattedStream.h"
34 #include "llvm/Target/TargetFrameLowering.h"
35 #include "llvm/Target/TargetOptions.h"
36 #include "llvm/Target/TargetRegisterInfo.h"
37 using namespace llvm;
38 
39 ARMException::ARMException(AsmPrinter *A)
40   : DwarfException(A),
41     shouldEmitCFI(false) {}
42 
43 ARMException::~ARMException() {}
44 
45 ARMTargetStreamer &ARMException::getTargetStreamer() {
46   MCTargetStreamer &TS = *Asm->OutStreamer.getTargetStreamer();
47   return static_cast<ARMTargetStreamer &>(TS);
48 }
49 
50 /// endModule - Emit all exception information that should come after the
51 /// content.
52 void ARMException::endModule() {
53   if (shouldEmitCFI)
54     Asm->OutStreamer.EmitCFISections(false, true);
55 }
56 
57 /// beginFunction - Gather pre-function exception information. Assumes it's
58 /// being emitted immediately after the function entry point.
59 void ARMException::beginFunction(const MachineFunction *MF) {
60   getTargetStreamer().emitFnStart();
61   if (Asm->MF->getFunction()->needsUnwindTableEntry())
62     Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
63                                                   Asm->getFunctionNumber()));
64   // See if we need call frame info.
65   AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
66   assert(MoveType != AsmPrinter::CFI_M_EH &&
67          "non-EH CFI not yet supported in prologue with EHABI lowering");
68   if (MoveType == AsmPrinter::CFI_M_Debug) {
69     shouldEmitCFI = true;
70     Asm->OutStreamer.EmitCFIStartProc(false);
71   }
72 }
73 
74 /// endFunction - Gather and emit post-function exception information.
75 ///
76 void ARMException::endFunction(const MachineFunction *) {
77   if (shouldEmitCFI)
78     Asm->OutStreamer.EmitCFIEndProc();
79 
80   ARMTargetStreamer &ATS = getTargetStreamer();
81   if (!Asm->MF->getFunction()->needsUnwindTableEntry())
82     ATS.emitCantUnwind();
83   else {
84     Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
85                                                   Asm->getFunctionNumber()));
86 
87     // Map all labels and get rid of any dead landing pads.
88     MMI->TidyLandingPads();
89 
90     if (!MMI->getLandingPads().empty()) {
91       // Emit references to personality.
92       if (const Function * Personality =
93           MMI->getPersonalities()[MMI->getPersonalityIndex()]) {
94         MCSymbol *PerSym = Asm->getSymbol(Personality);
95         Asm->OutStreamer.EmitSymbolAttribute(PerSym, MCSA_Global);
96         ATS.emitPersonality(PerSym);
97       }
98 
99       // Emit .handlerdata directive.
100       ATS.emitHandlerData();
101 
102       // Emit actual exception table
103       EmitExceptionTable();
104     }
105   }
106 
107   ATS.emitFnEnd();
108 }
109 
110 void ARMException::EmitTypeInfos(unsigned TTypeEncoding) {
111   const std::vector<const GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
112   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
113 
114   bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
115 
116   int Entry = 0;
117   // Emit the Catch TypeInfos.
118   if (VerboseAsm && !TypeInfos.empty()) {
119     Asm->OutStreamer.AddComment(">> Catch TypeInfos <<");
120     Asm->OutStreamer.AddBlankLine();
121     Entry = TypeInfos.size();
122   }
123 
124   for (std::vector<const GlobalVariable *>::const_reverse_iterator
125          I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
126     const GlobalVariable *GV = *I;
127     if (VerboseAsm)
128       Asm->OutStreamer.AddComment("TypeInfo " + Twine(Entry--));
129     Asm->EmitTTypeReference(GV, TTypeEncoding);
130   }
131 
132   // Emit the Exception Specifications.
133   if (VerboseAsm && !FilterIds.empty()) {
134     Asm->OutStreamer.AddComment(">> Filter TypeInfos <<");
135     Asm->OutStreamer.AddBlankLine();
136     Entry = 0;
137   }
138   for (std::vector<unsigned>::const_iterator
139          I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
140     unsigned TypeID = *I;
141     if (VerboseAsm) {
142       --Entry;
143       if (TypeID != 0)
144         Asm->OutStreamer.AddComment("FilterInfo " + Twine(Entry));
145     }
146 
147     Asm->EmitTTypeReference((TypeID == 0 ? 0 : TypeInfos[TypeID - 1]),
148                             TTypeEncoding);
149   }
150 }
151