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/DataLayout.h"
  18 #include "llvm/IR/Mangler.h"
  19 #include "llvm/IR/Module.h"
  20 #include "llvm/MC/MCAsmInfo.h"
  21 #include "llvm/MC/MCExpr.h"
  22 #include "llvm/MC/MCSection.h"
  23 #include "llvm/MC/MCStreamer.h"
  24 #include "llvm/MC/MCSymbol.h"
  25 #include "llvm/Support/FormattedStream.h"
  26 #include "llvm/Target/TargetOptions.h"
  27 using namespace llvm;
  28
  29 ARMException::ARMException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {}
  30
  31 ARMException::~ARMException() {}
  32
  33 ARMTargetStreamer &ARMException::getTargetStreamer() {
  34   MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer();
  35   return static_cast<ARMTargetStreamer &>(TS);
  36 }
  37
  38 void ARMException::beginFunction(const MachineFunction *MF) {
  39   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
  40     getTargetStreamer().emitFnStart();
  41   // See if we need call frame info.
  42   AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
  43   assert(MoveType != AsmPrinter::CFI_M_EH &&
  44          "non-EH CFI not yet supported in prologue with EHABI lowering");
  45
  46   if (MoveType == AsmPrinter::CFI_M_Debug) {
  47     if (!hasEmittedCFISections) {
  48       if (Asm->needsOnlyDebugCFIMoves())
  49         Asm->OutStreamer->EmitCFISections(false, true);
  50       hasEmittedCFISections = true;
  51     }
  52
  53     shouldEmitCFI = true;
  54     Asm->OutStreamer->EmitCFIStartProc(false);
  55   }
  56 }
  57
  58 /// endFunction - Gather and emit post-function exception information.
  59 ///
  60 void ARMException::endFunction(const MachineFunction *MF) {
  61   ARMTargetStreamer &ATS = getTargetStreamer();
  62   const Function &F = MF->getFunction();
  63   const Function *Per = nullptr;
  64   if (F.hasPersonalityFn())
  65     Per = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
  66   bool forceEmitPersonality =
  67     F.hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
  68     F.needsUnwindTableEntry();
  69   bool shouldEmitPersonality = forceEmitPersonality ||
  70     !MF->getLandingPads().empty();
  71   if (!Asm->MF->getFunction().needsUnwindTableEntry() &&
  72       !shouldEmitPersonality)
  73     ATS.emitCantUnwind();
  74   else if (shouldEmitPersonality) {
  75     // Emit references to personality.
  76     if (Per) {
  77       MCSymbol *PerSym = Asm->getSymbol(Per);
  78       Asm->OutStreamer->EmitSymbolAttribute(PerSym, MCSA_Global);
  79       ATS.emitPersonality(PerSym);
  80     }
  81
  82     // Emit .handlerdata directive.
  83     ATS.emitHandlerData();
  84
  85     // Emit actual exception table
  86     emitExceptionTable();
  87   }
  88
  89   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
  90     ATS.emitFnEnd();
  91 }
  92
  93 void ARMException::emitTypeInfos(unsigned TTypeEncoding,
  94                                  MCSymbol *TTBaseLabel) {
  95   const MachineFunction *MF = Asm->MF;
  96   const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
  97   const std::vector<unsigned> &FilterIds = MF->getFilterIds();
  98
  99   bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
 100
 101   int Entry = 0;
 102   // Emit the Catch TypeInfos.
 103   if (VerboseAsm && !TypeInfos.empty()) {
 104     Asm->OutStreamer->AddComment(">> Catch TypeInfos <<");
 105     Asm->OutStreamer->AddBlankLine();
 106     Entry = TypeInfos.size();
 107   }
 108
 109   for (const GlobalValue *GV : reverse(TypeInfos)) {
 110     if (VerboseAsm)
 111       Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--));
 112     Asm->EmitTTypeReference(GV, TTypeEncoding);
 113   }
 114
 115   Asm->OutStreamer->EmitLabel(TTBaseLabel);
 116
 117   // Emit the Exception Specifications.
 118   if (VerboseAsm && !FilterIds.empty()) {
 119     Asm->OutStreamer->AddComment(">> Filter TypeInfos <<");
 120     Asm->OutStreamer->AddBlankLine();
 121     Entry = 0;
 122   }
 123   for (std::vector<unsigned>::const_iterator
 124          I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
 125     unsigned TypeID = *I;
 126     if (VerboseAsm) {
 127       --Entry;
 128       if (TypeID != 0)
 129         Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry));
 130     }
 131
 132     Asm->EmitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]),
 133                             TTypeEncoding);
 134   }
 135 }