1 //===- PostDominators.cpp - Post-Dominator Calculation --------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the post-dominator construction algorithms.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Analysis/PostDominators.h"
15 #include "llvm/IR/Function.h"
16 #include "llvm/IR/PassManager.h"
17 #include "llvm/Pass.h"
18 #include "llvm/Support/raw_ostream.h"
19 
20 using namespace llvm;
21 
22 #define DEBUG_TYPE "postdomtree"
23 
24 #ifdef EXPENSIVE_CHECKS
25 static constexpr bool ExpensiveChecksEnabled = true;
26 #else
27 static constexpr bool ExpensiveChecksEnabled = false;
28 #endif
29 
30 //===----------------------------------------------------------------------===//
31 //  PostDominatorTree Implementation
32 //===----------------------------------------------------------------------===//
33 
34 char PostDominatorTreeWrapperPass::ID = 0;
35 
36 INITIALIZE_PASS(PostDominatorTreeWrapperPass, "postdomtree",
37                 "Post-Dominator Tree Construction", true, true)
38 
39 bool PostDominatorTree::invalidate(Function &F, const PreservedAnalyses &PA,
40                                    FunctionAnalysisManager::Invalidator &) {
41   // Check whether the analysis, all analyses on functions, or the function's
42   // CFG have been preserved.
43   auto PAC = PA.getChecker<PostDominatorTreeAnalysis>();
44   return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>() ||
45            PAC.preservedSet<CFGAnalyses>());
46 }
47 
48 bool PostDominatorTreeWrapperPass::runOnFunction(Function &F) {
49   DT.recalculate(F);
50   return false;
51 }
52 
53 void PostDominatorTreeWrapperPass::verifyAnalysis() const {
54   if (VerifyDomInfo)
55     assert(DT.verify(PostDominatorTree::VerificationLevel::Full));
56   else if (ExpensiveChecksEnabled)
57     assert(DT.verify(PostDominatorTree::VerificationLevel::Basic));
58 }
59 
60 void PostDominatorTreeWrapperPass::print(raw_ostream &OS, const Module *) const {
61   DT.print(OS);
62 }
63 
64 FunctionPass* llvm::createPostDomTree() {
65   return new PostDominatorTreeWrapperPass();
66 }
67 
68 AnalysisKey PostDominatorTreeAnalysis::Key;
69 
70 PostDominatorTree PostDominatorTreeAnalysis::run(Function &F,
71                                                  FunctionAnalysisManager &) {
72   PostDominatorTree PDT(F);
73   return PDT;
74 }
75 
76 PostDominatorTreePrinterPass::PostDominatorTreePrinterPass(raw_ostream &OS)
77   : OS(OS) {}
78 
79 PreservedAnalyses
80 PostDominatorTreePrinterPass::run(Function &F, FunctionAnalysisManager &AM) {
81   OS << "PostDominatorTree for function: " << F.getName() << "\n";
82   AM.getResult<PostDominatorTreeAnalysis>(F).print(OS);
83 
84   return PreservedAnalyses::all();
85 }
86