LLVM 19.0.0git
EHPersonalities.cpp
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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
11#include "llvm/IR/CFG.h"
12#include "llvm/IR/Constants.h"
13#include "llvm/IR/Function.h"
15#include "llvm/IR/Module.h"
16#include "llvm/Support/Debug.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.
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 .Case("__zos_cxx_personality_v2", EHPersonality::ZOS_CXX)
46 .Default(EHPersonality::Unknown);
47}
48
50 switch (Pers) {
51 case EHPersonality::GNU_Ada:
52 return "__gnat_eh_personality";
53 case EHPersonality::GNU_CXX:
54 return "__gxx_personality_v0";
55 case EHPersonality::GNU_CXX_SjLj:
56 return "__gxx_personality_sj0";
57 case EHPersonality::GNU_C:
58 return "__gcc_personality_v0";
59 case EHPersonality::GNU_C_SjLj:
60 return "__gcc_personality_sj0";
61 case EHPersonality::GNU_ObjC:
62 return "__objc_personality_v0";
63 case EHPersonality::MSVC_X86SEH:
64 return "_except_handler3";
65 case EHPersonality::MSVC_TableSEH:
66 return "__C_specific_handler";
67 case EHPersonality::MSVC_CXX:
68 return "__CxxFrameHandler3";
69 case EHPersonality::CoreCLR:
70 return "ProcessCLRException";
71 case EHPersonality::Rust:
72 return "rust_eh_personality";
73 case EHPersonality::Wasm_CXX:
74 return "__gxx_wasm_personality_v0";
75 case EHPersonality::XL_CXX:
76 return "__xlcxx_personality_v1";
77 case EHPersonality::ZOS_CXX:
78 return "__zos_cxx_personality_v2";
79 case EHPersonality::Unknown:
80 llvm_unreachable("Unknown EHPersonality!");
81 }
82
83 llvm_unreachable("Invalid EHPersonality!");
84}
85
87 if (T.isPS5())
88 return EHPersonality::GNU_CXX;
89 else
90 return EHPersonality::GNU_C;
91}
92
94 EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
95 // We can't simplify any invokes to nounwind functions if the personality
96 // function wants to catch asynch exceptions. The nounwind attribute only
97 // implies that the function does not throw synchronous exceptions.
98
99 // Cannot simplify CXX Personality under AsynchEH
100 const llvm::Module *M = (const llvm::Module *)F->getParent();
101 bool EHa = M->getModuleFlag("eh-asynch");
102 return !EHa && !isAsynchronousEHPersonality(Personality);
103}
104
107 BasicBlock *EntryBlock = &F.getEntryBlock();
109
110 // Build up the color map, which maps each block to its set of 'colors'.
111 // For any block B the "colors" of B are the set of funclets F (possibly
112 // including a root "funclet" representing the main function) such that
113 // F will need to directly contain B or a copy of B (where the term "directly
114 // contain" is used to distinguish from being "transitively contained" in
115 // a nested funclet).
116 //
117 // Note: Despite not being a funclet in the truest sense, a catchswitch is
118 // considered to belong to its own funclet for the purposes of coloring.
119
120 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
121 dbgs() << "\nColoring funclets for " << F.getName() << "\n");
122
123 Worklist.push_back({EntryBlock, EntryBlock});
124
125 while (!Worklist.empty()) {
126 BasicBlock *Visiting;
127 BasicBlock *Color;
128 std::tie(Visiting, Color) = Worklist.pop_back_val();
129 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
130 dbgs() << "Visiting " << Visiting->getName() << ", "
131 << Color->getName() << "\n");
132 Instruction *VisitingHead = Visiting->getFirstNonPHI();
133 if (VisitingHead->isEHPad()) {
134 // Mark this funclet head as a member of itself.
135 Color = Visiting;
136 }
137 // Note that this is a member of the given color.
138 ColorVector &Colors = BlockColors[Visiting];
139 if (!is_contained(Colors, Color))
140 Colors.push_back(Color);
141 else
142 continue;
143
144 DEBUG_WITH_TYPE("win-eh-prepare-coloring",
145 dbgs() << " Assigned color \'" << Color->getName()
146 << "\' to block \'" << Visiting->getName()
147 << "\'.\n");
148
149 BasicBlock *SuccColor = Color;
150 Instruction *Terminator = Visiting->getTerminator();
151 if (auto *CatchRet = dyn_cast<CatchReturnInst>(Terminator)) {
152 Value *ParentPad = CatchRet->getCatchSwitchParentPad();
153 if (isa<ConstantTokenNone>(ParentPad))
154 SuccColor = EntryBlock;
155 else
156 SuccColor = cast<Instruction>(ParentPad)->getParent();
157 }
158
159 for (BasicBlock *Succ : successors(Visiting))
160 Worklist.push_back({Succ, SuccColor});
161 }
162 return BlockColors;
163}
This file contains the declarations for the subclasses of Constant, which represent the different fla...
#define DEBUG_WITH_TYPE(TYPE, X)
DEBUG_WITH_TYPE macro - This macro should be used by passes to emit debug information.
Definition: Debug.h:64
This file provides various utilities for inspecting and working with the control flow graph in LLVM I...
#define F(x, y, z)
Definition: MD5.cpp:55
Module.h This file contains the declarations for the Module class.
This file implements the StringSwitch template, which mimics a switch() statement whose cases are str...
LLVM Basic Block Representation.
Definition: BasicBlock.h:60
const Instruction * getFirstNonPHI() const
Returns a pointer to the first instruction in this block that is not a PHINode instruction.
Definition: BasicBlock.cpp:361
const Function * getParent() const
Return the enclosing method, or null if none.
Definition: BasicBlock.h:208
const Instruction * getTerminator() const LLVM_READONLY
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Definition: BasicBlock.h:223
bool isEHPad() const
Return true if the instruction is a variety of EH-block.
Definition: Instruction.h:828
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
bool empty() const
Definition: SmallVector.h:94
void push_back(const T &Elt)
Definition: SmallVector.h:426
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1209
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
A switch()-like statement whose cases are string literals.
Definition: StringSwitch.h:44
StringSwitch & Case(StringLiteral S, T Value)
Definition: StringSwitch.h:69
R Default(T Value)
Definition: StringSwitch.h:182
TinyPtrVector - This class is specialized for cases where there are normally 0 or 1 element in a vect...
Definition: TinyPtrVector.h:29
void push_back(EltTy NewVal)
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:44
LLVM Value Representation.
Definition: Value.h:74
const Value * stripPointerCasts() const
Strip off pointer casts, all-zero GEPs and address space casts.
Definition: Value.cpp:693
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:309
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
StringRef getEHPersonalityName(EHPersonality Pers)
auto successors(const MachineBasicBlock *BB)
DenseMap< BasicBlock *, ColorVector > colorEHFunclets(Function &F)
If an EH funclet personality is in use (see isFuncletEHPersonality), this will recompute which blocks...
bool canSimplifyInvokeNoUnwind(const Function *F)
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:163
EHPersonality classifyEHPersonality(const Value *Pers)
See if the given exception handling personality function is one that we understand.
bool isAsynchronousEHPersonality(EHPersonality Pers)
Returns true if this personality function catches asynchronous exceptions.
bool is_contained(R &&Range, const E &Element)
Returns true if Element is found in Range.
Definition: STLExtras.h:1879
EHPersonality getDefaultEHPersonality(const Triple &T)