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"
18using 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.
22EHPersonality 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_sj0", EHPersonality::GNU_CXX_SjLj)
31    .Case("__gcc_personality_v0",  EHPersonality::GNU_C)
32    .Case("__gcc_personality_sj0", EHPersonality::GNU_C_SjLj)
33    .Case("__objc_personality_v0", EHPersonality::GNU_ObjC)
34    .Case("_except_handler3",      EHPersonality::MSVC_X86SEH)
35    .Case("_except_handler4",      EHPersonality::MSVC_X86SEH)
36    .Case("__C_specific_handler",  EHPersonality::MSVC_Win64SEH)
37    .Case("__CxxFrameHandler3",    EHPersonality::MSVC_CXX)
38    .Case("ProcessCLRException",   EHPersonality::CoreCLR)
39    .Case("rust_eh_personality",   EHPersonality::Rust)
40    .Default(EHPersonality::Unknown);
41}
42
43bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
44  EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
45  // We can't simplify any invokes to nounwind functions if the personality
46  // function wants to catch asynch exceptions.  The nounwind attribute only
47  // implies that the function does not throw synchronous exceptions.
48  return !isAsynchronousEHPersonality(Personality);
49}
50
51DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
52  SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
53  BasicBlock *EntryBlock = &F.getEntryBlock();
54  DenseMap<BasicBlock *, ColorVector> BlockColors;
55
56  // Build up the color map, which maps each block to its set of 'colors'.
57  // For any block B the "colors" of B are the set of funclets F (possibly
58  // including a root "funclet" representing the main function) such that
59  // F will need to directly contain B or a copy of B (where the term "directly
60  // contain" is used to distinguish from being "transitively contained" in
61  // a nested funclet).
62  //
63  // Note: Despite not being a funclet in the truest sense, a catchswitch is
64  // considered to belong to its own funclet for the purposes of coloring.
65
66  DEBUG_WITH_TYPE("winehprepare-coloring", dbgs() << "\nColoring funclets for "
67                                                  << F.getName() << "\n");
68
69  Worklist.push_back({EntryBlock, EntryBlock});
70
71  while (!Worklist.empty()) {
72    BasicBlock *Visiting;
73    BasicBlock *Color;
74    std::tie(Visiting, Color) = Worklist.pop_back_val();
75    DEBUG_WITH_TYPE("winehprepare-coloring",
76                    dbgs() << "Visiting " << Visiting->getName() << ", "
77                           << Color->getName() << "\n");
78    Instruction *VisitingHead = Visiting->getFirstNonPHI();
79    if (VisitingHead->isEHPad()) {
80      // Mark this funclet head as a member of itself.
81      Color = Visiting;
82    }
83    // Note that this is a member of the given color.
84    ColorVector &Colors = BlockColors[Visiting];
85    if (std::find(Colors.begin(), Colors.end(), Color) == Colors.end())
86      Colors.push_back(Color);
87    else
88      continue;
89
90    DEBUG_WITH_TYPE("winehprepare-coloring",
91                    dbgs() << "  Assigned color \'" << Color->getName()
92                           << "\' to block \'" << Visiting->getName()
93                           << "\'.\n");
94
95    BasicBlock *SuccColor = Color;
96    TerminatorInst *Terminator = Visiting->getTerminator();
97    if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
98      Value *ParentPad = CatchRet->getCatchSwitchParentPad();
99      if (isa<ConstantTokenNone>(ParentPad))
100        SuccColor = EntryBlock;
101      else
102        SuccColor = cast<Instruction>(ParentPad)->getParent();
103    }
104
105    for (BasicBlock *Succ : successors(Visiting))
106      Worklist.push_back({Succ, SuccColor});
107  }
108  return BlockColors;
109}
110