llvm/lib/CodeGen/AsmPrinter/ARMException.cpp

   1 //===-- CodeGen/AsmPrinter/ARMException.cpp - ARM EHABI Exception Impl ----===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file contains support for writing DWARF exception info into asm files.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "DwarfException.h"
  14 #include "llvm/ADT/Twine.h"
  15 #include "llvm/CodeGen/AsmPrinter.h"
  16 #include "llvm/CodeGen/MachineFunction.h"
  17 #include "llvm/IR/Function.h"
  18 #include "llvm/MC/MCAsmInfo.h"
  19 #include "llvm/MC/MCStreamer.h"
  20 using namespace llvm;
  21
  22 ARMException::ARMException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {}
  23
  24 ARMException::~ARMException() = default;
  25
  26 ARMTargetStreamer &ARMException::getTargetStreamer() {
  27   MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer();
  28   return static_cast<ARMTargetStreamer &>(TS);
  29 }
  30
  31 void ARMException::beginFunction(const MachineFunction *MF) {
  32   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
  33     getTargetStreamer().emitFnStart();
  34   // See if we need call frame info.
  35   AsmPrinter::CFISection CFISecType = Asm->getFunctionCFISectionType(*MF);
  36   assert(CFISecType != AsmPrinter::CFISection::EH &&
  37          "non-EH CFI not yet supported in prologue with EHABI lowering");
  38
  39   if (CFISecType == AsmPrinter::CFISection::Debug) {
  40     if (!hasEmittedCFISections) {
  41       if (Asm->getModuleCFISectionType() == AsmPrinter::CFISection::Debug)
  42         Asm->OutStreamer->emitCFISections(false, true);
  43       hasEmittedCFISections = true;
  44     }
  45
  46     shouldEmitCFI = true;
  47     Asm->OutStreamer->emitCFIStartProc(false);
  48   }
  49 }
  50
  51 /// endFunction - Gather and emit post-function exception information.
  52 ///
  53 void ARMException::endFunction(const MachineFunction *MF) {
  54   ARMTargetStreamer &ATS = getTargetStreamer();
  55   const Function &F = MF->getFunction();
  56   const Function *Per = nullptr;
  57   if (F.hasPersonalityFn())
  58     Per = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
  59   bool forceEmitPersonality =
  60     F.hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
  61     F.needsUnwindTableEntry();
  62   bool shouldEmitPersonality = forceEmitPersonality ||
  63     !MF->getLandingPads().empty();
  64   if (!Asm->MF->getFunction().needsUnwindTableEntry() &&
  65       !shouldEmitPersonality)
  66     ATS.emitCantUnwind();
  67   else if (shouldEmitPersonality) {
  68     // Emit references to personality.
  69     if (Per) {
  70       MCSymbol *PerSym = Asm->getSymbol(Per);
  71       ATS.emitPersonality(PerSym);
  72     }
  73
  74     // Emit .handlerdata directive.
  75     ATS.emitHandlerData();
  76
  77     // Emit actual exception table
  78     emitExceptionTable();
  79   }
  80
  81   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
  82     ATS.emitFnEnd();
  83 }
  84
  85 void ARMException::emitTypeInfos(unsigned TTypeEncoding,
  86                                  MCSymbol *TTBaseLabel) {
  87   const MachineFunction *MF = Asm->MF;
  88   const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
  89   const std::vector<unsigned> &FilterIds = MF->getFilterIds();
  90
  91   bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
  92
  93   int Entry = 0;
  94   // Emit the Catch TypeInfos.
  95   if (VerboseAsm && !TypeInfos.empty()) {
  96     Asm->OutStreamer->AddComment(">> Catch TypeInfos <<");
  97     Asm->OutStreamer->addBlankLine();
  98     Entry = TypeInfos.size();
  99   }
 100
 101   for (const GlobalValue *GV : reverse(TypeInfos)) {
 102     if (VerboseAsm)
 103       Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--));
 104     Asm->emitTTypeReference(GV, TTypeEncoding);
 105   }
 106
 107   Asm->OutStreamer->emitLabel(TTBaseLabel);
 108
 109   // Emit the Exception Specifications.
 110   if (VerboseAsm && !FilterIds.empty()) {
 111     Asm->OutStreamer->AddComment(">> Filter TypeInfos <<");
 112     Asm->OutStreamer->addBlankLine();
 113     Entry = 0;
 114   }
 115   for (std::vector<unsigned>::const_iterator
 116          I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
 117     unsigned TypeID = *I;
 118     if (VerboseAsm) {
 119       --Entry;
 120       if (TypeID != 0)
 121         Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry));
 122     }
 123
 124     Asm->emitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]),
 125                             TTypeEncoding);
 126   }
 127 }