1//===-- CodeGen/AsmPrinter/ARMException.cpp - ARM EHABI Exception Impl ----===//
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// This file contains support for writing DWARF exception info into asm files.
10//
11//===----------------------------------------------------------------------===//
12
13#include "DwarfException.h"
14#include "llvm/ADT/Twine.h"
15#include "llvm/CodeGen/AsmPrinter.h"
16#include "llvm/CodeGen/MachineFunction.h"
17#include "llvm/IR/Function.h"
18#include "llvm/MC/MCAsmInfo.h"
19#include "llvm/MC/MCStreamer.h"
20using namespace llvm;
21
22ARMException::ARMException(AsmPrinter *A) : EHStreamer(A) {}
23
24ARMException::~ARMException() = default;
25
26ARMTargetStreamer &ARMException::getTargetStreamer() {
27 MCTargetStreamer &TS = *Asm->OutStreamer->getTargetStreamer();
28 return static_cast<ARMTargetStreamer &>(TS);
29}
30
31void ARMException::beginFunction(const MachineFunction *MF) {
32 if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
33 getTargetStreamer().emitFnStart();
34 // See if we need call frame info.
35 AsmPrinter::CFISection CFISecType = Asm->getFunctionCFISectionType(MF: *MF);
36 assert(CFISecType != AsmPrinter::CFISection::EH &&
37 "non-EH CFI not yet supported in prologue with EHABI lowering");
38
39 if (CFISecType == AsmPrinter::CFISection::Debug) {
40 if (!hasEmittedCFISections) {
41 if (Asm->getModuleCFISectionType() == AsmPrinter::CFISection::Debug)
42 Asm->OutStreamer->emitCFISections(EH: false, Debug: true);
43 hasEmittedCFISections = true;
44 }
45
46 shouldEmitCFI = true;
47 Asm->OutStreamer->emitCFIStartProc(IsSimple: false);
48 }
49}
50
51void ARMException::markFunctionEnd() {
52 if (shouldEmitCFI)
53 Asm->OutStreamer->emitCFIEndProc();
54}
55
56/// endFunction - Gather and emit post-function exception information.
57///
58void ARMException::endFunction(const MachineFunction *MF) {
59 ARMTargetStreamer &ATS = getTargetStreamer();
60 const Function &F = MF->getFunction();
61 const Function *Per = nullptr;
62 if (F.hasPersonalityFn())
63 Per = dyn_cast<Function>(Val: F.getPersonalityFn()->stripPointerCasts());
64 bool forceEmitPersonality =
65 F.hasPersonalityFn() && !isNoOpWithoutInvoke(Pers: classifyEHPersonality(Pers: Per)) &&
66 F.needsUnwindTableEntry();
67 bool shouldEmitPersonality = forceEmitPersonality ||
68 !MF->getLandingPads().empty();
69 if (!Asm->MF->getFunction().needsUnwindTableEntry() &&
70 !shouldEmitPersonality)
71 ATS.emitCantUnwind();
72 else if (shouldEmitPersonality) {
73 // Emit references to personality.
74 if (Per) {
75 MCSymbol *PerSym = Asm->getSymbol(GV: Per);
76 ATS.emitPersonality(Personality: PerSym);
77 }
78
79 // Emit .handlerdata directive.
80 ATS.emitHandlerData();
81
82 // Emit actual exception table
83 emitExceptionTable();
84 }
85
86 if (Asm->MAI->getExceptionHandlingType() == ExceptionHandling::ARM)
87 ATS.emitFnEnd();
88}
89
90void ARMException::emitTypeInfos(unsigned TTypeEncoding,
91 MCSymbol *TTBaseLabel) {
92 const MachineFunction *MF = Asm->MF;
93 const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
94 const std::vector<unsigned> &FilterIds = MF->getFilterIds();
95
96 bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
97
98 int Entry = 0;
99 // Emit the Catch TypeInfos.
100 if (VerboseAsm && !TypeInfos.empty()) {
101 Asm->OutStreamer->AddComment(T: ">> Catch TypeInfos <<");
102 Asm->OutStreamer->addBlankLine();
103 Entry = TypeInfos.size();
104 }
105
106 for (const GlobalValue *GV : reverse(C: TypeInfos)) {
107 if (VerboseAsm)
108 Asm->OutStreamer->AddComment(T: "TypeInfo " + Twine(Entry--));
109 Asm->emitTTypeReference(GV, Encoding: TTypeEncoding);
110 }
111
112 Asm->OutStreamer->emitLabel(Symbol: TTBaseLabel);
113
114 // Emit the Exception Specifications.
115 if (VerboseAsm && !FilterIds.empty()) {
116 Asm->OutStreamer->AddComment(T: ">> Filter TypeInfos <<");
117 Asm->OutStreamer->addBlankLine();
118 Entry = 0;
119 }
120 for (std::vector<unsigned>::const_iterator
121 I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
122 unsigned TypeID = *I;
123 if (VerboseAsm) {
124 --Entry;
125 if (TypeID != 0)
126 Asm->OutStreamer->AddComment(T: "FilterInfo " + Twine(Entry));
127 }
128
129 Asm->emitTTypeReference(GV: (TypeID == 0 ? nullptr : TypeInfos[TypeID - 1]),
130 Encoding: TTypeEncoding);
131 }
132}
133