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) : EHStreamer(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 void ARMException::markFunctionEnd() {
  52   if (shouldEmitCFI)
  53     Asm->OutStreamer->emitCFIEndProc();
  54 }
  55
  56 /// endFunction - Gather and emit post-function exception information.
  57 ///
  58 void ARMException::endFunction(const MachineFunction *MF) {
  59   ARMTargetStreamer &ATS = getTargetStreamer();
  60   const Function &F = MF->getFunction();
  61   const Function *Per = nullptr;
  62   if (F.hasPersonalityFn())
  63     Per = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
  64   bool forceEmitPersonality =
  65     F.hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
  66     F.needsUnwindTableEntry();
  67   bool shouldEmitPersonality = forceEmitPersonality ||
  68     !MF->getLandingPads().empty();
  69   if (!Asm->MF->getFunction().needsUnwindTableEntry() &&
  70       !shouldEmitPersonality)
  71     ATS.emitCantUnwind();
  72   else if (shouldEmitPersonality) {
  73     // Emit references to personality.
  74     if (Per) {
  75       MCSymbol *PerSym = Asm->getSymbol(Per);
  76       ATS.emitPersonality(PerSym);
  77     }
  78
  79     // Emit .handlerdata directive.
  80     ATS.emitHandlerData();
  81
  82     // Emit actual exception table
  83     emitExceptionTable();
  84   }
  85
  86   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
  87     ATS.emitFnEnd();
  88 }
  89
  90 void ARMException::emitTypeInfos(unsigned TTypeEncoding,
  91                                  MCSymbol *TTBaseLabel) {
  92   const MachineFunction *MF = Asm->MF;
  93   const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
  94   const std::vector<unsigned> &FilterIds = MF->getFilterIds();
  95
  96   bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
  97
  98   int Entry = 0;
  99   // Emit the Catch TypeInfos.
 100   if (VerboseAsm && !TypeInfos.empty()) {
 101     Asm->OutStreamer->AddComment(">> Catch TypeInfos <<");
 102     Asm->OutStreamer->addBlankLine();
 103     Entry = TypeInfos.size();
 104   }
 105
 106   for (const GlobalValue *GV : reverse(TypeInfos)) {
 107     if (VerboseAsm)
 108       Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--));
 109     Asm->emitTTypeReference(GV, TTypeEncoding);
 110   }
 111
 112   Asm->OutStreamer->emitLabel(TTBaseLabel);
 113
 114   // Emit the Exception Specifications.
 115   if (VerboseAsm && !FilterIds.empty()) {
 116     Asm->OutStreamer->AddComment(">> Filter TypeInfos <<");
 117     Asm->OutStreamer->addBlankLine();
 118     Entry = 0;
 119   }
 120   for (std::vector<unsigned>::const_iterator
 121          I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
 122     unsigned TypeID = *I;
 123     if (VerboseAsm) {
 124       --Entry;
 125       if (TypeID != 0)
 126         Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry));
 127     }
 128
 129     Asm->emitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]),
 130                             TTypeEncoding);
 131   }
 132 }