1//===- Pass.cpp - LLVM Pass Infrastructure Implementation -----------------===//
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 implements the LLVM Pass infrastructure. It is primarily
10// responsible with ensuring that passes are executed and batched together
11// optimally.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Pass.h"
16#include "llvm/Config/llvm-config.h"
17#include "llvm/IR/Function.h"
18#include "llvm/IR/IRPrintingPasses.h"
19#include "llvm/IR/LLVMContext.h"
20#include "llvm/IR/LegacyPassNameParser.h"
21#include "llvm/IR/Module.h"
22#include "llvm/IR/OptBisect.h"
23#include "llvm/PassInfo.h"
24#include "llvm/PassRegistry.h"
25#include "llvm/Support/Compiler.h"
26#include "llvm/Support/Debug.h"
27#include "llvm/Support/raw_ostream.h"
28#include <cassert>
29
30#ifdef EXPENSIVE_CHECKS
31#include "llvm/IR/StructuralHash.h"
32#endif
33
34using namespace llvm;
35
36#define DEBUG_TYPE "ir"
37
38//===----------------------------------------------------------------------===//
39// Pass Implementation
40//
41
42// Force out-of-line virtual method.
43Pass::~Pass() {
44 delete Resolver;
45}
46
47// Force out-of-line virtual method.
48ModulePass::~ModulePass() = default;
49
50Pass *ModulePass::createPrinterPass(raw_ostream &OS,
51 const std::string &Banner) const {
52 return createPrintModulePass(OS, Banner);
53}
54
55PassManagerType ModulePass::getPotentialPassManagerType() const {
56 return PMT_ModulePassManager;
57}
58
59static std::string getDescription(const Module &M) {
60 return "module (" + M.getName().str() + ")";
61}
62
63bool ModulePass::skipModule(Module &M) const {
64 OptPassGate &Gate = M.getContext().getOptPassGate();
65 return Gate.isEnabled() &&
66 !Gate.shouldRunPass(PassName: this->getPassName(), IRDescription: getDescription(M));
67}
68
69bool Pass::mustPreserveAnalysisID(char &AID) const {
70 return Resolver->getAnalysisIfAvailable(ID: &AID) != nullptr;
71}
72
73// dumpPassStructure - Implement the -debug-pass=Structure option
74void Pass::dumpPassStructure(unsigned Offset) {
75 dbgs().indent(NumSpaces: Offset*2) << getPassName() << "\n";
76}
77
78/// getPassName - Return a nice clean name for a pass. This usually
79/// implemented in terms of the name that is registered by one of the
80/// Registration templates, but can be overloaded directly.
81StringRef Pass::getPassName() const {
82 AnalysisID AID = getPassID();
83 const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(TI: AID);
84 if (PI)
85 return PI->getPassName();
86 return "Unnamed pass: implement Pass::getPassName()";
87}
88
89void Pass::preparePassManager(PMStack &) {
90 // By default, don't do anything.
91}
92
93PassManagerType Pass::getPotentialPassManagerType() const {
94 // Default implementation.
95 return PMT_Unknown;
96}
97
98void Pass::getAnalysisUsage(AnalysisUsage &) const {
99 // By default, no analysis results are used, all are invalidated.
100}
101
102void Pass::releaseMemory() {
103 // By default, don't do anything.
104}
105
106void Pass::verifyAnalysis() const {
107 // By default, don't do anything.
108}
109
110void *Pass::getAdjustedAnalysisPointer(AnalysisID AID) {
111 return this;
112}
113
114ImmutablePass *Pass::getAsImmutablePass() {
115 return nullptr;
116}
117
118PMDataManager *Pass::getAsPMDataManager() {
119 return nullptr;
120}
121
122void Pass::setResolver(AnalysisResolver *AR) {
123 assert(!Resolver && "Resolver is already set");
124 Resolver = AR;
125}
126
127// print - Print out the internal state of the pass. This is called by Analyze
128// to print out the contents of an analysis. Otherwise it is not necessary to
129// implement this method.
130void Pass::print(raw_ostream &OS, const Module *) const {
131 OS << "Pass::print not implemented for pass: '" << getPassName() << "'!\n";
132}
133
134#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
135// dump - call print(cerr);
136LLVM_DUMP_METHOD void Pass::dump() const {
137 print(OS&: dbgs(), nullptr);
138}
139#endif
140
141#ifdef EXPENSIVE_CHECKS
142uint64_t Pass::structuralHash(Module &M) const {
143 return StructuralHash(M, true);
144}
145
146uint64_t Pass::structuralHash(Function &F) const {
147 return StructuralHash(F, true);
148}
149#endif
150
151//===----------------------------------------------------------------------===//
152// ImmutablePass Implementation
153//
154// Force out-of-line virtual method.
155ImmutablePass::~ImmutablePass() = default;
156
157void ImmutablePass::initializePass() {
158 // By default, don't do anything.
159}
160
161//===----------------------------------------------------------------------===//
162// FunctionPass Implementation
163//
164
165Pass *FunctionPass::createPrinterPass(raw_ostream &OS,
166 const std::string &Banner) const {
167 return createPrintFunctionPass(OS, Banner);
168}
169
170PassManagerType FunctionPass::getPotentialPassManagerType() const {
171 return PMT_FunctionPassManager;
172}
173
174static std::string getDescription(const Function &F) {
175 return "function (" + F.getName().str() + ")";
176}
177
178bool FunctionPass::skipFunction(const Function &F) const {
179 OptPassGate &Gate = F.getContext().getOptPassGate();
180 if (Gate.isEnabled() &&
181 !Gate.shouldRunPass(PassName: this->getPassName(), IRDescription: getDescription(F)))
182 return true;
183
184 if (F.hasOptNone()) {
185 LLVM_DEBUG(dbgs() << "Skipping pass '" << getPassName() << "' on function "
186 << F.getName() << "\n");
187 return true;
188 }
189 return false;
190}
191
192const PassInfo *Pass::lookupPassInfo(const void *TI) {
193 return PassRegistry::getPassRegistry()->getPassInfo(TI);
194}
195
196const PassInfo *Pass::lookupPassInfo(StringRef Arg) {
197 return PassRegistry::getPassRegistry()->getPassInfo(Arg);
198}
199
200Pass *Pass::createPass(AnalysisID ID) {
201 const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(TI: ID);
202 if (!PI)
203 return nullptr;
204 return PI->createPass();
205}
206
207//===----------------------------------------------------------------------===//
208// Analysis Group Implementation Code
209//===----------------------------------------------------------------------===//
210
211// RegisterAGBase implementation
212
213RegisterAGBase::RegisterAGBase(StringRef Name, const void *InterfaceID,
214 const void *PassID, bool isDefault)
215 : PassInfo(Name, InterfaceID) {
216 PassRegistry::getPassRegistry()->registerAnalysisGroup(InterfaceID, PassID,
217 Registeree&: *this, isDefault);
218}
219
220//===----------------------------------------------------------------------===//
221// PassRegistrationListener implementation
222//
223
224// enumeratePasses - Iterate over the registered passes, calling the
225// passEnumerate callback on each PassInfo object.
226void PassRegistrationListener::enumeratePasses() {
227 PassRegistry::getPassRegistry()->enumerateWith(L: this);
228}
229
230PassNameParser::PassNameParser(cl::Option &O)
231 : cl::parser<const PassInfo *>(O) {
232 PassRegistry::getPassRegistry()->addRegistrationListener(L: this);
233}
234
235// This only gets called during static destruction, in which case the
236// PassRegistry will have already been destroyed by llvm_shutdown(). So
237// attempting to remove the registration listener is an error.
238PassNameParser::~PassNameParser() = default;
239
240//===----------------------------------------------------------------------===//
241// AnalysisUsage Class Implementation
242//
243
244namespace {
245
246struct GetCFGOnlyPasses : public PassRegistrationListener {
247 using VectorType = AnalysisUsage::VectorType;
248
249 VectorType &CFGOnlyList;
250
251 GetCFGOnlyPasses(VectorType &L) : CFGOnlyList(L) {}
252
253 void passEnumerate(const PassInfo *P) override {
254 if (P->isCFGOnlyPass())
255 CFGOnlyList.push_back(Elt: P->getTypeInfo());
256 }
257};
258
259} // end anonymous namespace
260
261// setPreservesCFG - This function should be called to by the pass, iff they do
262// not:
263//
264// 1. Add or remove basic blocks from the function
265// 2. Modify terminator instructions in any way.
266//
267// This function annotates the AnalysisUsage info object to say that analyses
268// that only depend on the CFG are preserved by this pass.
269void AnalysisUsage::setPreservesCFG() {
270 // Since this transformation doesn't modify the CFG, it preserves all analyses
271 // that only depend on the CFG (like dominators, loop info, etc...)
272 GetCFGOnlyPasses(Preserved).enumeratePasses();
273}
274
275AnalysisUsage &AnalysisUsage::addPreserved(StringRef Arg) {
276 const PassInfo *PI = Pass::lookupPassInfo(Arg);
277 // If the pass exists, preserve it. Otherwise silently do nothing.
278 if (PI)
279 pushUnique(Set&: Preserved, ID: PI->getTypeInfo());
280 return *this;
281}
282
283AnalysisUsage &AnalysisUsage::addRequiredID(const void *ID) {
284 pushUnique(Set&: Required, ID);
285 return *this;
286}
287
288AnalysisUsage &AnalysisUsage::addRequiredID(char &ID) {
289 pushUnique(Set&: Required, ID: &ID);
290 return *this;
291}
292
293AnalysisUsage &AnalysisUsage::addRequiredTransitiveID(char &ID) {
294 pushUnique(Set&: Required, ID: &ID);
295 pushUnique(Set&: RequiredTransitive, ID: &ID);
296 return *this;
297}
298

source code of llvm/lib/IR/Pass.cpp