reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
//===- EHPersonalities.cpp - Compute EH-related information ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "llvm/Analysis/EHPersonalities.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;

/// See if the given exception handling personality function is one that we
/// understand.  If so, return a description of it; otherwise return Unknown.
EHPersonality llvm::classifyEHPersonality(const Value *Pers) {
  const Function *F =
      Pers ? dyn_cast<Function>(Pers->stripPointerCasts()) : nullptr;
  if (!F)
    return EHPersonality::Unknown;
  return StringSwitch<EHPersonality>(F->getName())
    .Case("__gnat_eh_personality",     EHPersonality::GNU_Ada)
    .Case("__gxx_personality_v0",      EHPersonality::GNU_CXX)
    .Case("__gxx_personality_seh0",    EHPersonality::GNU_CXX)
    .Case("__gxx_personality_sj0",     EHPersonality::GNU_CXX_SjLj)
    .Case("__gcc_personality_v0",      EHPersonality::GNU_C)
    .Case("__gcc_personality_seh0",    EHPersonality::GNU_C)
    .Case("__gcc_personality_sj0",     EHPersonality::GNU_C_SjLj)
    .Case("__objc_personality_v0",     EHPersonality::GNU_ObjC)
    .Case("_except_handler3",          EHPersonality::MSVC_X86SEH)
    .Case("_except_handler4",          EHPersonality::MSVC_X86SEH)
    .Case("__C_specific_handler",      EHPersonality::MSVC_Win64SEH)
    .Case("__CxxFrameHandler3",        EHPersonality::MSVC_CXX)
    .Case("ProcessCLRException",       EHPersonality::CoreCLR)
    .Case("rust_eh_personality",       EHPersonality::Rust)
    .Case("__gxx_wasm_personality_v0", EHPersonality::Wasm_CXX)
    .Default(EHPersonality::Unknown);
}

StringRef llvm::getEHPersonalityName(EHPersonality Pers) {
  switch (Pers) {
  case EHPersonality::GNU_Ada:       return "__gnat_eh_personality";
  case EHPersonality::GNU_CXX:       return "__gxx_personality_v0";
  case EHPersonality::GNU_CXX_SjLj:  return "__gxx_personality_sj0";
  case EHPersonality::GNU_C:         return "__gcc_personality_v0";
  case EHPersonality::GNU_C_SjLj:    return "__gcc_personality_sj0";
  case EHPersonality::GNU_ObjC:      return "__objc_personality_v0";
  case EHPersonality::MSVC_X86SEH:   return "_except_handler3";
  case EHPersonality::MSVC_Win64SEH: return "__C_specific_handler";
  case EHPersonality::MSVC_CXX:      return "__CxxFrameHandler3";
  case EHPersonality::CoreCLR:       return "ProcessCLRException";
  case EHPersonality::Rust:          return "rust_eh_personality";
  case EHPersonality::Wasm_CXX:      return "__gxx_wasm_personality_v0";
  case EHPersonality::Unknown:       llvm_unreachable("Unknown EHPersonality!");
  }

  llvm_unreachable("Invalid EHPersonality!");
}

EHPersonality llvm::getDefaultEHPersonality(const Triple &T) {
  return EHPersonality::GNU_C;
}

bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
  EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
  // We can't simplify any invokes to nounwind functions if the personality
  // function wants to catch asynch exceptions.  The nounwind attribute only
  // implies that the function does not throw synchronous exceptions.
  return !isAsynchronousEHPersonality(Personality);
}

DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
  SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
  BasicBlock *EntryBlock = &F.getEntryBlock();
  DenseMap<BasicBlock *, ColorVector> BlockColors;

  // Build up the color map, which maps each block to its set of 'colors'.
  // For any block B the "colors" of B are the set of funclets F (possibly
  // including a root "funclet" representing the main function) such that
  // F will need to directly contain B or a copy of B (where the term "directly
  // contain" is used to distinguish from being "transitively contained" in
  // a nested funclet).
  //
  // Note: Despite not being a funclet in the truest sense, a catchswitch is
  // considered to belong to its own funclet for the purposes of coloring.

  DEBUG_WITH_TYPE("winehprepare-coloring", dbgs() << "\nColoring funclets for "
                                                  << F.getName() << "\n");

  Worklist.push_back({EntryBlock, EntryBlock});

  while (!Worklist.empty()) {
    BasicBlock *Visiting;
    BasicBlock *Color;
    std::tie(Visiting, Color) = Worklist.pop_back_val();
    DEBUG_WITH_TYPE("winehprepare-coloring",
                    dbgs() << "Visiting " << Visiting->getName() << ", "
                           << Color->getName() << "\n");
    Instruction *VisitingHead = Visiting->getFirstNonPHI();
    if (VisitingHead->isEHPad()) {
      // Mark this funclet head as a member of itself.
      Color = Visiting;
    }
    // Note that this is a member of the given color.
    ColorVector &Colors = BlockColors[Visiting];
    if (!is_contained(Colors, Color))
      Colors.push_back(Color);
    else
      continue;

    DEBUG_WITH_TYPE("winehprepare-coloring",
                    dbgs() << "  Assigned color \'" << Color->getName()
                           << "\' to block \'" << Visiting->getName()
                           << "\'.\n");

    BasicBlock *SuccColor = Color;
    Instruction *Terminator = Visiting->getTerminator();
    if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
      Value *ParentPad = CatchRet->getCatchSwitchParentPad();
      if (isa<ConstantTokenNone>(ParentPad))
        SuccColor = EntryBlock;
      else
        SuccColor = cast<Instruction>(ParentPad)->getParent();
    }

    for (BasicBlock *Succ : successors(Visiting))
      Worklist.push_back({Succ, SuccColor});
  }
  return BlockColors;
}