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.
classifyEHPersonality(const Value * Pers)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 .Case("__gxx_wasm_personality_v0", EHPersonality::Wasm_CXX)
43 .Default(EHPersonality::Unknown);
44 }
45
getEHPersonalityName(EHPersonality Pers)46 StringRef llvm::getEHPersonalityName(EHPersonality Pers) {
47 switch (Pers) {
48 case EHPersonality::GNU_Ada: return "__gnat_eh_personality";
49 case EHPersonality::GNU_CXX: return "__gxx_personality_v0";
50 case EHPersonality::GNU_CXX_SjLj: return "__gxx_personality_sj0";
51 case EHPersonality::GNU_C: return "__gcc_personality_v0";
52 case EHPersonality::GNU_C_SjLj: return "__gcc_personality_sj0";
53 case EHPersonality::GNU_ObjC: return "__objc_personality_v0";
54 case EHPersonality::MSVC_X86SEH: return "_except_handler3";
55 case EHPersonality::MSVC_Win64SEH: return "__C_specific_handler";
56 case EHPersonality::MSVC_CXX: return "__CxxFrameHandler3";
57 case EHPersonality::CoreCLR: return "ProcessCLRException";
58 case EHPersonality::Rust: return "rust_eh_personality";
59 case EHPersonality::Wasm_CXX: return "__gxx_wasm_personality_v0";
60 case EHPersonality::Unknown: llvm_unreachable("Unknown EHPersonality!");
61 }
62
63 llvm_unreachable("Invalid EHPersonality!");
64 }
65
getDefaultEHPersonality(const Triple & T)66 EHPersonality llvm::getDefaultEHPersonality(const Triple &T) {
67 return EHPersonality::GNU_C;
68 }
69
canSimplifyInvokeNoUnwind(const Function * F)70 bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
71 EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
72 // We can't simplify any invokes to nounwind functions if the personality
73 // function wants to catch asynch exceptions. The nounwind attribute only
74 // implies that the function does not throw synchronous exceptions.
75 return !isAsynchronousEHPersonality(Personality);
76 }
77
colorEHFunclets(Function & F)78 DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
79 SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
80 BasicBlock *EntryBlock = &F.getEntryBlock();
81 DenseMap<BasicBlock *, ColorVector> BlockColors;
82
83 // Build up the color map, which maps each block to its set of 'colors'.
84 // For any block B the "colors" of B are the set of funclets F (possibly
85 // including a root "funclet" representing the main function) such that
86 // F will need to directly contain B or a copy of B (where the term "directly
87 // contain" is used to distinguish from being "transitively contained" in
88 // a nested funclet).
89 //
90 // Note: Despite not being a funclet in the truest sense, a catchswitch is
91 // considered to belong to its own funclet for the purposes of coloring.
92
93 DEBUG_WITH_TYPE("winehprepare-coloring", dbgs() << "\nColoring funclets for "
94 << F.getName() << "\n");
95
96 Worklist.push_back({EntryBlock, EntryBlock});
97
98 while (!Worklist.empty()) {
99 BasicBlock *Visiting;
100 BasicBlock *Color;
101 std::tie(Visiting, Color) = Worklist.pop_back_val();
102 DEBUG_WITH_TYPE("winehprepare-coloring",
103 dbgs() << "Visiting " << Visiting->getName() << ", "
104 << Color->getName() << "\n");
105 Instruction *VisitingHead = Visiting->getFirstNonPHI();
106 if (VisitingHead->isEHPad()) {
107 // Mark this funclet head as a member of itself.
108 Color = Visiting;
109 }
110 // Note that this is a member of the given color.
111 ColorVector &Colors = BlockColors[Visiting];
112 if (!is_contained(Colors, Color))
113 Colors.push_back(Color);
114 else
115 continue;
116
117 DEBUG_WITH_TYPE("winehprepare-coloring",
118 dbgs() << " Assigned color \'" << Color->getName()
119 << "\' to block \'" << Visiting->getName()
120 << "\'.\n");
121
122 BasicBlock *SuccColor = Color;
123 TerminatorInst *Terminator = Visiting->getTerminator();
124 if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
125 Value *ParentPad = CatchRet->getCatchSwitchParentPad();
126 if (isa<ConstantTokenNone>(ParentPad))
127 SuccColor = EntryBlock;
128 else
129 SuccColor = cast<Instruction>(ParentPad)->getParent();
130 }
131
132 for (BasicBlock *Succ : successors(Visiting))
133 Worklist.push_back({Succ, SuccColor});
134 }
135 return BlockColors;
136 }
137