1 //===- EHPersonalities.cpp - Compute EH-related information ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "llvm/Analysis/EHPersonalities.h"
10 #include "llvm/ADT/StringSwitch.h"
11 #include "llvm/ADT/Triple.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 GlobalValue *F =
24 Pers ? dyn_cast<GlobalValue>(Pers->stripPointerCasts()) : nullptr;
25 if (!F || !F->getValueType() || !F->getValueType()->isFunctionTy())
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_TableSEH)
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 .Case("__xlcxx_personality_v1", EHPersonality::XL_CXX)
44 .Default(EHPersonality::Unknown);
45 }
46
getEHPersonalityName(EHPersonality Pers)47 StringRef llvm::getEHPersonalityName(EHPersonality Pers) {
48 switch (Pers) {
49 case EHPersonality::GNU_Ada: return "__gnat_eh_personality";
50 case EHPersonality::GNU_CXX: return "__gxx_personality_v0";
51 case EHPersonality::GNU_CXX_SjLj: return "__gxx_personality_sj0";
52 case EHPersonality::GNU_C: return "__gcc_personality_v0";
53 case EHPersonality::GNU_C_SjLj: return "__gcc_personality_sj0";
54 case EHPersonality::GNU_ObjC: return "__objc_personality_v0";
55 case EHPersonality::MSVC_X86SEH: return "_except_handler3";
56 case EHPersonality::MSVC_TableSEH:
57 return "__C_specific_handler";
58 case EHPersonality::MSVC_CXX: return "__CxxFrameHandler3";
59 case EHPersonality::CoreCLR: return "ProcessCLRException";
60 case EHPersonality::Rust: return "rust_eh_personality";
61 case EHPersonality::Wasm_CXX: return "__gxx_wasm_personality_v0";
62 case EHPersonality::XL_CXX:
63 return "__xlcxx_personality_v1";
64 case EHPersonality::Unknown: llvm_unreachable("Unknown EHPersonality!");
65 }
66
67 llvm_unreachable("Invalid EHPersonality!");
68 }
69
getDefaultEHPersonality(const Triple & T)70 EHPersonality llvm::getDefaultEHPersonality(const Triple &T) {
71 if (T.isPS5())
72 return EHPersonality::GNU_CXX;
73 else
74 return EHPersonality::GNU_C;
75 }
76
canSimplifyInvokeNoUnwind(const Function * F)77 bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
78 EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
79 // We can't simplify any invokes to nounwind functions if the personality
80 // function wants to catch asynch exceptions. The nounwind attribute only
81 // implies that the function does not throw synchronous exceptions.
82 return !isAsynchronousEHPersonality(Personality);
83 }
84
colorEHFunclets(Function & F)85 DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
86 SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
87 BasicBlock *EntryBlock = &F.getEntryBlock();
88 DenseMap<BasicBlock *, ColorVector> BlockColors;
89
90 // Build up the color map, which maps each block to its set of 'colors'.
91 // For any block B the "colors" of B are the set of funclets F (possibly
92 // including a root "funclet" representing the main function) such that
93 // F will need to directly contain B or a copy of B (where the term "directly
94 // contain" is used to distinguish from being "transitively contained" in
95 // a nested funclet).
96 //
97 // Note: Despite not being a funclet in the truest sense, a catchswitch is
98 // considered to belong to its own funclet for the purposes of coloring.
99
100 DEBUG_WITH_TYPE("winehprepare-coloring", dbgs() << "\nColoring funclets for "
101 << F.getName() << "\n");
102
103 Worklist.push_back({EntryBlock, EntryBlock});
104
105 while (!Worklist.empty()) {
106 BasicBlock *Visiting;
107 BasicBlock *Color;
108 std::tie(Visiting, Color) = Worklist.pop_back_val();
109 DEBUG_WITH_TYPE("winehprepare-coloring",
110 dbgs() << "Visiting " << Visiting->getName() << ", "
111 << Color->getName() << "\n");
112 Instruction *VisitingHead = Visiting->getFirstNonPHI();
113 if (VisitingHead->isEHPad()) {
114 // Mark this funclet head as a member of itself.
115 Color = Visiting;
116 }
117 // Note that this is a member of the given color.
118 ColorVector &Colors = BlockColors[Visiting];
119 if (!is_contained(Colors, Color))
120 Colors.push_back(Color);
121 else
122 continue;
123
124 DEBUG_WITH_TYPE("winehprepare-coloring",
125 dbgs() << " Assigned color \'" << Color->getName()
126 << "\' to block \'" << Visiting->getName()
127 << "\'.\n");
128
129 BasicBlock *SuccColor = Color;
130 Instruction *Terminator = Visiting->getTerminator();
131 if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
132 Value *ParentPad = CatchRet->getCatchSwitchParentPad();
133 if (isa<ConstantTokenNone>(ParentPad))
134 SuccColor = EntryBlock;
135 else
136 SuccColor = cast<Instruction>(ParentPad)->getParent();
137 }
138
139 for (BasicBlock *Succ : successors(Visiting))
140 Worklist.push_back({Succ, SuccColor});
141 }
142 return BlockColors;
143 }
144