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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 
ARMException(AsmPrinter * A)39 ARMException::ARMException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {}
40 
~ARMException()41 ARMException::~ARMException() {}
42 
getTargetStreamer()43 ARMTargetStreamer &ARMException::getTargetStreamer() {
44   MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer();
45   return static_cast<ARMTargetStreamer &>(TS);
46 }
47 
48 /// endModule - Emit all exception information that should come after the
49 /// content.
endModule()50 void ARMException::endModule() {
51   if (shouldEmitCFI)
52     Asm->OutStreamer->EmitCFISections(false, true);
53 }
54 
beginFunction(const MachineFunction * MF)55 void ARMException::beginFunction(const MachineFunction *MF) {
56   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
57     getTargetStreamer().emitFnStart();
58   // See if we need call frame info.
59   AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
60   assert(MoveType != AsmPrinter::CFI_M_EH &&
61          "non-EH CFI not yet supported in prologue with EHABI lowering");
62   if (MoveType == AsmPrinter::CFI_M_Debug) {
63     shouldEmitCFI = true;
64     Asm->OutStreamer->EmitCFIStartProc(false);
65   }
66 }
67 
68 /// endFunction - Gather and emit post-function exception information.
69 ///
endFunction(const MachineFunction * MF)70 void ARMException::endFunction(const MachineFunction *MF) {
71   ARMTargetStreamer &ATS = getTargetStreamer();
72   const Function *F = MF->getFunction();
73   const Function *Per = nullptr;
74   if (F->hasPersonalityFn())
75     Per = dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
76   bool forceEmitPersonality =
77     F->hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
78     F->needsUnwindTableEntry();
79   bool shouldEmitPersonality = forceEmitPersonality ||
80     !MMI->getLandingPads().empty();
81   if (!Asm->MF->getFunction()->needsUnwindTableEntry() &&
82       !shouldEmitPersonality)
83     ATS.emitCantUnwind();
84   else if (shouldEmitPersonality) {
85     // Emit references to personality.
86     if (Per) {
87       MCSymbol *PerSym = Asm->getSymbol(Per);
88       Asm->OutStreamer->EmitSymbolAttribute(PerSym, MCSA_Global);
89       ATS.emitPersonality(PerSym);
90     }
91 
92     // Emit .handlerdata directive.
93     ATS.emitHandlerData();
94 
95     // Emit actual exception table
96     emitExceptionTable();
97   }
98 
99   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
100     ATS.emitFnEnd();
101 }
102 
emitTypeInfos(unsigned TTypeEncoding)103 void ARMException::emitTypeInfos(unsigned TTypeEncoding) {
104   const std::vector<const GlobalValue *> &TypeInfos = MMI->getTypeInfos();
105   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
106 
107   bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
108 
109   int Entry = 0;
110   // Emit the Catch TypeInfos.
111   if (VerboseAsm && !TypeInfos.empty()) {
112     Asm->OutStreamer->AddComment(">> Catch TypeInfos <<");
113     Asm->OutStreamer->AddBlankLine();
114     Entry = TypeInfos.size();
115   }
116 
117   for (const GlobalValue *GV : reverse(TypeInfos)) {
118     if (VerboseAsm)
119       Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--));
120     Asm->EmitTTypeReference(GV, TTypeEncoding);
121   }
122 
123   // Emit the Exception Specifications.
124   if (VerboseAsm && !FilterIds.empty()) {
125     Asm->OutStreamer->AddComment(">> Filter TypeInfos <<");
126     Asm->OutStreamer->AddBlankLine();
127     Entry = 0;
128   }
129   for (std::vector<unsigned>::const_iterator
130          I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
131     unsigned TypeID = *I;
132     if (VerboseAsm) {
133       --Entry;
134       if (TypeID != 0)
135         Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry));
136     }
137 
138     Asm->EmitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]),
139                             TTypeEncoding);
140   }
141 }
142