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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/StringExtras.h"
     16 #include "llvm/ADT/Twine.h"
     17 #include "llvm/CodeGen/AsmPrinter.h"
     18 #include "llvm/CodeGen/MachineFrameInfo.h"
     19 #include "llvm/CodeGen/MachineFunction.h"
     20 #include "llvm/CodeGen/MachineModuleInfo.h"
     21 #include "llvm/IR/DataLayout.h"
     22 #include "llvm/IR/Mangler.h"
     23 #include "llvm/IR/Module.h"
     24 #include "llvm/MC/MCAsmInfo.h"
     25 #include "llvm/MC/MCContext.h"
     26 #include "llvm/MC/MCExpr.h"
     27 #include "llvm/MC/MCSection.h"
     28 #include "llvm/MC/MCStreamer.h"
     29 #include "llvm/MC/MCSymbol.h"
     30 #include "llvm/Support/Dwarf.h"
     31 #include "llvm/Support/FormattedStream.h"
     32 #include "llvm/Target/TargetFrameLowering.h"
     33 #include "llvm/Target/TargetOptions.h"
     34 #include "llvm/Target/TargetRegisterInfo.h"
     35 using namespace llvm;
     36 
     37 ARMException::ARMException(AsmPrinter *A) : DwarfCFIExceptionBase(A) {}
     38 
     39 ARMException::~ARMException() {}
     40 
     41 ARMTargetStreamer &ARMException::getTargetStreamer() {
     42   MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer();
     43   return static_cast<ARMTargetStreamer &>(TS);
     44 }
     45 
     46 /// endModule - Emit all exception information that should come after the
     47 /// content.
     48 void ARMException::endModule() {
     49   if (shouldEmitCFI)
     50     Asm->OutStreamer->EmitCFISections(false, true);
     51 }
     52 
     53 void ARMException::beginFunction(const MachineFunction *MF) {
     54   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
     55     getTargetStreamer().emitFnStart();
     56   // See if we need call frame info.
     57   AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
     58   assert(MoveType != AsmPrinter::CFI_M_EH &&
     59          "non-EH CFI not yet supported in prologue with EHABI lowering");
     60   if (MoveType == AsmPrinter::CFI_M_Debug) {
     61     shouldEmitCFI = true;
     62     Asm->OutStreamer->EmitCFIStartProc(false);
     63   }
     64 }
     65 
     66 /// endFunction - Gather and emit post-function exception information.
     67 ///
     68 void ARMException::endFunction(const MachineFunction *MF) {
     69   ARMTargetStreamer &ATS = getTargetStreamer();
     70   const Function *F = MF->getFunction();
     71   const Function *Per = nullptr;
     72   if (F->hasPersonalityFn())
     73     Per = dyn_cast<Function>(F->getPersonalityFn()->stripPointerCasts());
     74   bool forceEmitPersonality =
     75     F->hasPersonalityFn() && !isNoOpWithoutInvoke(classifyEHPersonality(Per)) &&
     76     F->needsUnwindTableEntry();
     77   bool shouldEmitPersonality = forceEmitPersonality ||
     78     !MMI->getLandingPads().empty();
     79   if (!Asm->MF->getFunction()->needsUnwindTableEntry() &&
     80       !shouldEmitPersonality)
     81     ATS.emitCantUnwind();
     82   else if (shouldEmitPersonality) {
     83     // Emit references to personality.
     84     if (Per) {
     85       MCSymbol *PerSym = Asm->getSymbol(Per);
     86       Asm->OutStreamer->EmitSymbolAttribute(PerSym, MCSA_Global);
     87       ATS.emitPersonality(PerSym);
     88     }
     89 
     90     // Emit .handlerdata directive.
     91     ATS.emitHandlerData();
     92 
     93     // Emit actual exception table
     94     emitExceptionTable();
     95   }
     96 
     97   if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
     98     ATS.emitFnEnd();
     99 }
    100 
    101 void ARMException::emitTypeInfos(unsigned TTypeEncoding) {
    102   const std::vector<const GlobalValue *> &TypeInfos = MMI->getTypeInfos();
    103   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
    104 
    105   bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
    106 
    107   int Entry = 0;
    108   // Emit the Catch TypeInfos.
    109   if (VerboseAsm && !TypeInfos.empty()) {
    110     Asm->OutStreamer->AddComment(">> Catch TypeInfos <<");
    111     Asm->OutStreamer->AddBlankLine();
    112     Entry = TypeInfos.size();
    113   }
    114 
    115   for (const GlobalValue *GV : reverse(TypeInfos)) {
    116     if (VerboseAsm)
    117       Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--));
    118     Asm->EmitTTypeReference(GV, TTypeEncoding);
    119   }
    120 
    121   // Emit the Exception Specifications.
    122   if (VerboseAsm && !FilterIds.empty()) {
    123     Asm->OutStreamer->AddComment(">> Filter TypeInfos <<");
    124     Asm->OutStreamer->AddBlankLine();
    125     Entry = 0;
    126   }
    127   for (std::vector<unsigned>::const_iterator
    128          I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
    129     unsigned TypeID = *I;
    130     if (VerboseAsm) {
    131       --Entry;
    132       if (TypeID != 0)
    133         Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry));
    134     }
    135 
    136     Asm->EmitTTypeReference((TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]),
    137                             TTypeEncoding);
    138   }
    139 }
    140