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 
42 ARMException::~ARMException() {}
43 
44 ARMTargetStreamer &ARMException::getTargetStreamer() {
45   MCTargetStreamer &TS = *Asm->OutStreamer.getTargetStreamer();
46   return static_cast<ARMTargetStreamer &>(TS);
47 }
48 
49 void ARMException::endModule() {
50 }
51 
52 /// beginFunction - Gather pre-function exception information. Assumes it's
53 /// being emitted immediately after the function entry point.
54 void ARMException::beginFunction(const MachineFunction *MF) {
55   getTargetStreamer().emitFnStart();
56   if (Asm->MF->getFunction()->needsUnwindTableEntry())
57     Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
58                                                   Asm->getFunctionNumber()));
59 }
60 
61 /// endFunction - Gather and emit post-function exception information.
62 ///
63 void ARMException::endFunction(const MachineFunction *) {
64   ARMTargetStreamer &ATS = getTargetStreamer();
65   if (!Asm->MF->getFunction()->needsUnwindTableEntry())
66     ATS.emitCantUnwind();
67   else {
68     Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
69                                                   Asm->getFunctionNumber()));
70 
71     // Map all labels and get rid of any dead landing pads.
72     MMI->TidyLandingPads();
73 
74     if (!MMI->getLandingPads().empty()) {
75       // Emit references to personality.
76       if (const Function * Personality =
77           MMI->getPersonalities()[MMI->getPersonalityIndex()]) {
78         MCSymbol *PerSym = Asm->getSymbol(Personality);
79         Asm->OutStreamer.EmitSymbolAttribute(PerSym, MCSA_Global);
80         ATS.emitPersonality(PerSym);
81       }
82 
83       // Emit .handlerdata directive.
84       ATS.emitHandlerData();
85 
86       // Emit actual exception table
87       EmitExceptionTable();
88     }
89   }
90 
91   ATS.emitFnEnd();
92 }
93 
94 void ARMException::EmitTypeInfos(unsigned TTypeEncoding) {
95   const std::vector<const GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
96   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
97 
98   bool VerboseAsm = Asm->OutStreamer.isVerboseAsm();
99 
100   int Entry = 0;
101   // Emit the Catch TypeInfos.
102   if (VerboseAsm && !TypeInfos.empty()) {
103     Asm->OutStreamer.AddComment(">> Catch TypeInfos <<");
104     Asm->OutStreamer.AddBlankLine();
105     Entry = TypeInfos.size();
106   }
107 
108   for (std::vector<const GlobalVariable *>::const_reverse_iterator
109          I = TypeInfos.rbegin(), E = TypeInfos.rend(); I != E; ++I) {
110     const GlobalVariable *GV = *I;
111     if (VerboseAsm)
112       Asm->OutStreamer.AddComment("TypeInfo " + Twine(Entry--));
113     Asm->EmitTTypeReference(GV, TTypeEncoding);
114   }
115 
116   // Emit the Exception Specifications.
117   if (VerboseAsm && !FilterIds.empty()) {
118     Asm->OutStreamer.AddComment(">> Filter TypeInfos <<");
119     Asm->OutStreamer.AddBlankLine();
120     Entry = 0;
121   }
122   for (std::vector<unsigned>::const_iterator
123          I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
124     unsigned TypeID = *I;
125     if (VerboseAsm) {
126       --Entry;
127       if (TypeID != 0)
128         Asm->OutStreamer.AddComment("FilterInfo " + Twine(Entry));
129     }
130 
131     Asm->EmitTTypeReference((TypeID == 0 ? 0 : TypeInfos[TypeID - 1]),
132                             TTypeEncoding);
133   }
134 }
135