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"
19using 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.
23EHPersonality llvm::classifyEHPersonality(const Value *Pers) {
24 const GlobalValue *F =
25 Pers ? dyn_cast<GlobalValue>(Val: Pers->stripPointerCasts()) : nullptr;
26 if (!F || !F->getValueType() || !F->getValueType()->isFunctionTy())
27 return EHPersonality::Unknown;
28
29 StringRef Name = F->getName();
30 if (F->getParent()->getTargetTriple().isWindowsArm64EC()) {
31 // ARM64EC function symbols are mangled by prefixing them with "#".
32 // Demangle them by skipping this prefix.
33 Name.consume_front(Prefix: "#");
34 }
35
36 return StringSwitch<EHPersonality>(Name)
37 .Case(S: "__gnat_eh_personality", Value: EHPersonality::GNU_Ada)
38 .Case(S: "__gxx_personality_v0", Value: EHPersonality::GNU_CXX)
39 .Case(S: "__gxx_personality_seh0", Value: EHPersonality::GNU_CXX)
40 .Case(S: "__gxx_personality_sj0", Value: EHPersonality::GNU_CXX_SjLj)
41 .Case(S: "__gcc_personality_v0", Value: EHPersonality::GNU_C)
42 .Case(S: "__gcc_personality_seh0", Value: EHPersonality::GNU_C)
43 .Case(S: "__gcc_personality_sj0", Value: EHPersonality::GNU_C_SjLj)
44 .Case(S: "__objc_personality_v0", Value: EHPersonality::GNU_ObjC)
45 .Case(S: "_except_handler3", Value: EHPersonality::MSVC_X86SEH)
46 .Case(S: "_except_handler4", Value: EHPersonality::MSVC_X86SEH)
47 .Case(S: "__C_specific_handler", Value: EHPersonality::MSVC_TableSEH)
48 .Case(S: "__CxxFrameHandler3", Value: EHPersonality::MSVC_CXX)
49 .Case(S: "ProcessCLRException", Value: EHPersonality::CoreCLR)
50 .Case(S: "rust_eh_personality", Value: EHPersonality::Rust)
51 .Case(S: "__gxx_wasm_personality_v0", Value: EHPersonality::Wasm_CXX)
52 .Case(S: "__xlcxx_personality_v1", Value: EHPersonality::XL_CXX)
53 .Case(S: "__zos_cxx_personality_v2", Value: EHPersonality::ZOS_CXX)
54 .Default(Value: EHPersonality::Unknown);
55}
56
57StringRef llvm::getEHPersonalityName(EHPersonality Pers) {
58 switch (Pers) {
59 case EHPersonality::GNU_Ada:
60 return "__gnat_eh_personality";
61 case EHPersonality::GNU_CXX:
62 return "__gxx_personality_v0";
63 case EHPersonality::GNU_CXX_SjLj:
64 return "__gxx_personality_sj0";
65 case EHPersonality::GNU_C:
66 return "__gcc_personality_v0";
67 case EHPersonality::GNU_C_SjLj:
68 return "__gcc_personality_sj0";
69 case EHPersonality::GNU_ObjC:
70 return "__objc_personality_v0";
71 case EHPersonality::MSVC_X86SEH:
72 return "_except_handler3";
73 case EHPersonality::MSVC_TableSEH:
74 return "__C_specific_handler";
75 case EHPersonality::MSVC_CXX:
76 return "__CxxFrameHandler3";
77 case EHPersonality::CoreCLR:
78 return "ProcessCLRException";
79 case EHPersonality::Rust:
80 return "rust_eh_personality";
81 case EHPersonality::Wasm_CXX:
82 return "__gxx_wasm_personality_v0";
83 case EHPersonality::XL_CXX:
84 return "__xlcxx_personality_v1";
85 case EHPersonality::ZOS_CXX:
86 return "__zos_cxx_personality_v2";
87 case EHPersonality::Unknown:
88 llvm_unreachable("Unknown EHPersonality!");
89 }
90
91 llvm_unreachable("Invalid EHPersonality!");
92}
93
94EHPersonality llvm::getDefaultEHPersonality(const Triple &T) {
95 if (T.isPS5())
96 return EHPersonality::GNU_CXX;
97 else
98 return EHPersonality::GNU_C;
99}
100
101bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
102 EHPersonality Personality = classifyEHPersonality(Pers: F->getPersonalityFn());
103 // We can't simplify any invokes to nounwind functions if the personality
104 // function wants to catch asynch exceptions. The nounwind attribute only
105 // implies that the function does not throw synchronous exceptions.
106
107 // Cannot simplify CXX Personality under AsynchEH
108 const llvm::Module *M = (const llvm::Module *)F->getParent();
109 bool EHa = M->getModuleFlag(Key: "eh-asynch");
110 return !EHa && !isAsynchronousEHPersonality(Pers: Personality);
111}
112
113DenseMap<BasicBlock *, ColorVector> llvm::colorEHFunclets(Function &F) {
114 SmallVector<std::pair<BasicBlock *, BasicBlock *>, 16> Worklist;
115 BasicBlock *EntryBlock = &F.getEntryBlock();
116 DenseMap<BasicBlock *, ColorVector> BlockColors;
117
118 // Build up the color map, which maps each block to its set of 'colors'.
119 // For any block B the "colors" of B are the set of funclets F (possibly
120 // including a root "funclet" representing the main function) such that
121 // F will need to directly contain B or a copy of B (where the term "directly
122 // contain" is used to distinguish from being "transitively contained" in
123 // a nested funclet).
124 //
125 // Note: Despite not being a funclet in the truest sense, a catchswitch is
126 // considered to belong to its own funclet for the purposes of coloring.
127
128 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
129 dbgs() << "\nColoring funclets for " << F.getName() << "\n");
130
131 Worklist.push_back(Elt: {EntryBlock, EntryBlock});
132
133 while (!Worklist.empty()) {
134 BasicBlock *Visiting;
135 BasicBlock *Color;
136 std::tie(args&: Visiting, args&: Color) = Worklist.pop_back_val();
137 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
138 dbgs() << "Visiting " << Visiting->getName() << ", "
139 << Color->getName() << "\n");
140 BasicBlock::iterator VisitingHead = Visiting->getFirstNonPHIIt();
141 if (VisitingHead->isEHPad()) {
142 // Mark this funclet head as a member of itself.
143 Color = Visiting;
144 }
145 // Note that this is a member of the given color.
146 ColorVector &Colors = BlockColors[Visiting];
147 if (!is_contained(Range&: Colors, Element: Color))
148 Colors.push_back(NewVal: Color);
149 else
150 continue;
151
152 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
153 dbgs() << " Assigned color \'" << Color->getName()
154 << "\' to block \'" << Visiting->getName()
155 << "\'.\n");
156
157 BasicBlock *SuccColor = Color;
158 Instruction *Terminator = Visiting->getTerminator();
159 if (auto *CatchRet = dyn_cast<CatchReturnInst>(Val: Terminator)) {
160 Value *ParentPad = CatchRet->getCatchSwitchParentPad();
161 if (isa<ConstantTokenNone>(Val: ParentPad))
162 SuccColor = EntryBlock;
163 else
164 SuccColor = cast<Instruction>(Val: ParentPad)->getParent();
165 }
166
167 for (BasicBlock *Succ : successors(BB: Visiting))
168 Worklist.push_back(Elt: {Succ, SuccColor});
169 }
170 return BlockColors;
171}
172