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/IR/EHPersonalities.h"
10 #include "llvm/ADT/StringSwitch.h"
11 #include "llvm/IR/CFG.h"
12 #include "llvm/IR/Constants.h"
13 #include "llvm/IR/Function.h"
14 #include "llvm/IR/Instructions.h"
15 #include "llvm/IR/Module.h"
16 #include "llvm/Support/Debug.h"
17 #include "llvm/Support/raw_ostream.h"
18 #include "llvm/TargetParser/Triple.h"
19 using namespace llvm;
20
21 /// See if the given exception handling personality function is one that we
22 /// understand. If so, return a description of it; otherwise return Unknown.
classifyEHPersonality(const Value * Pers)23 EHPersonality llvm::classifyEHPersonality(const Value *Pers) {
24 const GlobalValue *F =
25 Pers ? dyn_cast<GlobalValue>(Pers->stripPointerCasts()) : nullptr;
26 if (!F || !F->getValueType() || !F->getValueType()->isFunctionTy())
27 return EHPersonality::Unknown;
28 return StringSwitch<EHPersonality>(F->getName())
29 .Case("__gnat_eh_personality", EHPersonality::GNU_Ada)
30 .Case("__gxx_personality_v0", EHPersonality::GNU_CXX)
31 .Case("__gxx_personality_seh0", EHPersonality::GNU_CXX)
32 .Case("__gxx_personality_sj0", EHPersonality::GNU_CXX_SjLj)
33 .Case("__gcc_personality_v0", EHPersonality::GNU_C)
34 .Case("__gcc_personality_seh0", EHPersonality::GNU_C)
35 .Case("__gcc_personality_sj0", EHPersonality::GNU_C_SjLj)
36 .Case("__objc_personality_v0", EHPersonality::GNU_ObjC)
37 .Case("_except_handler3", EHPersonality::MSVC_X86SEH)
38 .Case("_except_handler4", EHPersonality::MSVC_X86SEH)
39 .Case("__C_specific_handler", EHPersonality::MSVC_TableSEH)
40 .Case("__CxxFrameHandler3", EHPersonality::MSVC_CXX)
41 .Case("ProcessCLRException", EHPersonality::CoreCLR)
42 .Case("rust_eh_personality", EHPersonality::Rust)
43 .Case("__gxx_wasm_personality_v0", EHPersonality::Wasm_CXX)
44 .Case("__xlcxx_personality_v1", EHPersonality::XL_CXX)
45 .Default(EHPersonality::Unknown);
46 }
47
getEHPersonalityName(EHPersonality Pers)48 StringRef llvm::getEHPersonalityName(EHPersonality Pers) {
49 switch (Pers) {
50 case EHPersonality::GNU_Ada:
51 return "__gnat_eh_personality";
52 case EHPersonality::GNU_CXX:
53 return "__gxx_personality_v0";
54 case EHPersonality::GNU_CXX_SjLj:
55 return "__gxx_personality_sj0";
56 case EHPersonality::GNU_C:
57 return "__gcc_personality_v0";
58 case EHPersonality::GNU_C_SjLj:
59 return "__gcc_personality_sj0";
60 case EHPersonality::GNU_ObjC:
61 return "__objc_personality_v0";
62 case EHPersonality::MSVC_X86SEH:
63 return "_except_handler3";
64 case EHPersonality::MSVC_TableSEH:
65 return "__C_specific_handler";
66 case EHPersonality::MSVC_CXX:
67 return "__CxxFrameHandler3";
68 case EHPersonality::CoreCLR:
69 return "ProcessCLRException";
70 case EHPersonality::Rust:
71 return "rust_eh_personality";
72 case EHPersonality::Wasm_CXX:
73 return "__gxx_wasm_personality_v0";
74 case EHPersonality::XL_CXX:
75 return "__xlcxx_personality_v1";
76 case EHPersonality::Unknown:
77 llvm_unreachable("Unknown EHPersonality!");
78 }
79
80 llvm_unreachable("Invalid EHPersonality!");
81 }
82
getDefaultEHPersonality(const Triple & T)83 EHPersonality llvm::getDefaultEHPersonality(const Triple &T) {
84 if (T.isPS5())
85 return EHPersonality::GNU_CXX;
86 else
87 return EHPersonality::GNU_C;
88 }
89
canSimplifyInvokeNoUnwind(const Function * F)90 bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
91 EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
92 // We can't simplify any invokes to nounwind functions if the personality
93 // function wants to catch asynch exceptions. The nounwind attribute only
94 // implies that the function does not throw synchronous exceptions.
95
96 // Cannot simplify CXX Personality under AsynchEH
97 const llvm::Module *M = (const llvm::Module *)F->getParent();
98 bool EHa = M->getModuleFlag("eh-asynch");
99 return !EHa && !isAsynchronousEHPersonality(Personality);
100 }
101
colorEHFunclets(Function & F)102 DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
103 SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
104 BasicBlock *EntryBlock = &F.getEntryBlock();
105 DenseMap<BasicBlock *, ColorVector> BlockColors;
106
107 // Build up the color map, which maps each block to its set of 'colors'.
108 // For any block B the "colors" of B are the set of funclets F (possibly
109 // including a root "funclet" representing the main function) such that
110 // F will need to directly contain B or a copy of B (where the term "directly
111 // contain" is used to distinguish from being "transitively contained" in
112 // a nested funclet).
113 //
114 // Note: Despite not being a funclet in the truest sense, a catchswitch is
115 // considered to belong to its own funclet for the purposes of coloring.
116
117 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
118 dbgs() << "\nColoring funclets for " << F.getName() << "\n");
119
120 Worklist.push_back({EntryBlock, EntryBlock});
121
122 while (!Worklist.empty()) {
123 BasicBlock *Visiting;
124 BasicBlock *Color;
125 std::tie(Visiting, Color) = Worklist.pop_back_val();
126 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
127 dbgs() << "Visiting " << Visiting->getName() << ", "
128 << Color->getName() << "\n");
129 Instruction *VisitingHead = Visiting->getFirstNonPHI();
130 if (VisitingHead->isEHPad()) {
131 // Mark this funclet head as a member of itself.
132 Color = Visiting;
133 }
134 // Note that this is a member of the given color.
135 ColorVector &Colors = BlockColors[Visiting];
136 if (!is_contained(Colors, Color))
137 Colors.push_back(Color);
138 else
139 continue;
140
141 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
142 dbgs() << " Assigned color \'" << Color->getName()
143 << "\' to block \'" << Visiting->getName()
144 << "\'.\n");
145
146 BasicBlock *SuccColor = Color;
147 Instruction *Terminator = Visiting->getTerminator();
148 if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
149 Value *ParentPad = CatchRet->getCatchSwitchParentPad();
150 if (isa<ConstantTokenNone>(ParentPad))
151 SuccColor = EntryBlock;
152 else
153 SuccColor = cast<Instruction>(ParentPad)->getParent();
154 }
155
156 for (BasicBlock *Succ : successors(Visiting))
157 Worklist.push_back({Succ, SuccColor});
158 }
159 return BlockColors;
160 }
161