contrib/llvm/lib/Analysis/EHPersonalities.cpp

   1 //===- EHPersonalities.cpp - Compute EH-related information ---------------===//
   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 #include "llvm/Analysis/EHPersonalities.h"
  11 #include "llvm/ADT/StringSwitch.h"
  12 #include "llvm/IR/CFG.h"
  13 #include "llvm/IR/Constants.h"
  14 #include "llvm/IR/Function.h"
  15 #include "llvm/IR/Instructions.h"
  16 #include "llvm/Support/Debug.h"
  17 #include "llvm/Support/raw_ostream.h"
  18 using namespace llvm;
  19
  20 /// See if the given exception handling personality function is one that we
  21 /// understand.  If so, return a description of it; otherwise return Unknown.
  22 EHPersonality llvm::classifyEHPersonality(const Value *Pers) {
  23   const Function *F =
  24       Pers ? dyn_cast<Function>(Pers->stripPointerCasts()) : nullptr;
  25   if (!F)
  26     return EHPersonality::Unknown;
  27   return StringSwitch<EHPersonality>(F->getName())
  28     .Case("__gnat_eh_personality", EHPersonality::GNU_Ada)
  29     .Case("__gxx_personality_v0",  EHPersonality::GNU_CXX)
  30     .Case("__gxx_personality_seh0",EHPersonality::GNU_CXX)
  31     .Case("__gxx_personality_sj0", EHPersonality::GNU_CXX_SjLj)
  32     .Case("__gcc_personality_v0",  EHPersonality::GNU_C)
  33     .Case("__gcc_personality_seh0",EHPersonality::GNU_C)
  34     .Case("__gcc_personality_sj0", EHPersonality::GNU_C_SjLj)
  35     .Case("__objc_personality_v0", EHPersonality::GNU_ObjC)
  36     .Case("_except_handler3",      EHPersonality::MSVC_X86SEH)
  37     .Case("_except_handler4",      EHPersonality::MSVC_X86SEH)
  38     .Case("__C_specific_handler",  EHPersonality::MSVC_Win64SEH)
  39     .Case("__CxxFrameHandler3",    EHPersonality::MSVC_CXX)
  40     .Case("ProcessCLRException",   EHPersonality::CoreCLR)
  41     .Case("rust_eh_personality",   EHPersonality::Rust)
  42     .Default(EHPersonality::Unknown);
  43 }
  44
  45 StringRef llvm::getEHPersonalityName(EHPersonality Pers) {
  46   switch (Pers) {
  47   case EHPersonality::GNU_Ada:       return "__gnat_eh_personality";
  48   case EHPersonality::GNU_CXX:       return "__gxx_personality_v0";
  49   case EHPersonality::GNU_CXX_SjLj:  return "__gxx_personality_sj0";
  50   case EHPersonality::GNU_C:         return "__gcc_personality_v0";
  51   case EHPersonality::GNU_C_SjLj:    return "__gcc_personality_sj0";
  52   case EHPersonality::GNU_ObjC:      return "__objc_personality_v0";
  53   case EHPersonality::MSVC_X86SEH:   return "_except_handler3";
  54   case EHPersonality::MSVC_Win64SEH: return "__C_specific_handler";
  55   case EHPersonality::MSVC_CXX:      return "__CxxFrameHandler3";
  56   case EHPersonality::CoreCLR:       return "ProcessCLRException";
  57   case EHPersonality::Rust:          return "rust_eh_personality";
  58   case EHPersonality::Unknown:       llvm_unreachable("Unknown EHPersonality!");
  59   }
  60
  61   llvm_unreachable("Invalid EHPersonality!");
  62 }
  63
  64 EHPersonality llvm::getDefaultEHPersonality(const Triple &T) {
  65   return EHPersonality::GNU_C;
  66 }
  67
  68 bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
  69   EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
  70   // We can't simplify any invokes to nounwind functions if the personality
  71   // function wants to catch asynch exceptions.  The nounwind attribute only
  72   // implies that the function does not throw synchronous exceptions.
  73   return !isAsynchronousEHPersonality(Personality);
  74 }
  75
  76 DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
  77   SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
  78   BasicBlock *EntryBlock = &F.getEntryBlock();
  79   DenseMap<BasicBlock *, ColorVector> BlockColors;
  80
  81   // Build up the color map, which maps each block to its set of 'colors'.
  82   // For any block B the "colors" of B are the set of funclets F (possibly
  83   // including a root "funclet" representing the main function) such that
  84   // F will need to directly contain B or a copy of B (where the term "directly
  85   // contain" is used to distinguish from being "transitively contained" in
  86   // a nested funclet).
  87   //
  88   // Note: Despite not being a funclet in the truest sense, a catchswitch is
  89   // considered to belong to its own funclet for the purposes of coloring.
  90
  91   DEBUG_WITH_TYPE("winehprepare-coloring", dbgs() << "\nColoring funclets for "
  92                                                   << F.getName() << "\n");
  93
  94   Worklist.push_back({EntryBlock, EntryBlock});
  95
  96   while (!Worklist.empty()) {
  97     BasicBlock *Visiting;
  98     BasicBlock *Color;
  99     std::tie(Visiting, Color) = Worklist.pop_back_val();
 100     DEBUG_WITH_TYPE("winehprepare-coloring",
 101                     dbgs() << "Visiting " << Visiting->getName() << ", "
 102                            << Color->getName() << "\n");
 103     Instruction *VisitingHead = Visiting->getFirstNonPHI();
 104     if (VisitingHead->isEHPad()) {
 105       // Mark this funclet head as a member of itself.
 106       Color = Visiting;
 107     }
 108     // Note that this is a member of the given color.
 109     ColorVector &Colors = BlockColors[Visiting];
 110     if (!is_contained(Colors, Color))
 111       Colors.push_back(Color);
 112     else
 113       continue;
 114
 115     DEBUG_WITH_TYPE("winehprepare-coloring",
 116                     dbgs() << "  Assigned color \'" << Color->getName()
 117                            << "\' to block \'" << Visiting->getName()
 118                            << "\'.\n");
 119
 120     BasicBlock *SuccColor = Color;
 121     TerminatorInst *Terminator = Visiting->getTerminator();
 122     if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
 123       Value *ParentPad = CatchRet->getCatchSwitchParentPad();
 124       if (isa<ConstantTokenNone>(ParentPad))
 125         SuccColor = EntryBlock;
 126       else
 127         SuccColor = cast<Instruction>(ParentPad)->getParent();
 128     }
 129
 130     for (BasicBlock *Succ : successors(Visiting))
 131       Worklist.push_back({Succ, SuccColor});
 132   }
 133   return BlockColors;
 134 }