1 //===------ DumpFunctionPass.cpp --------------------------------*- C++ -*-===//
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 // Write a function to a file.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "polly/Support/DumpFunctionPass.h"
14 #include "llvm/IR/Module.h"
15 #include "llvm/Pass.h"
16 #include "llvm/Support/Debug.h"
17 #include "llvm/Support/FileSystem.h"
18 #include "llvm/Support/Path.h"
19 #include "llvm/Support/ToolOutputFile.h"
20 #include "llvm/Transforms/IPO/GlobalDCE.h"
21 #include "llvm/Transforms/IPO/StripDeadPrototypes.h"
22 #include "llvm/Transforms/Utils/Cloning.h"
23 
24 #define DEBUG_TYPE "polly-dump-func"
25 
26 using namespace llvm;
27 using namespace polly;
28 
29 namespace {
30 
31 static void runDumpFunction(llvm::Function &F, StringRef Suffix) {
32   StringRef FName = F.getName();
33   Module *M = F.getParent();
34 
35   StringRef ModuleName = M->getName();
36   StringRef Stem = sys::path::stem(ModuleName);
37   std::string Dumpfile = (Twine(Stem) + "-" + FName + Suffix + ".ll").str();
38   LLVM_DEBUG(dbgs() << "Dumping function '" << FName << "' to '" << Dumpfile
39                     << "'...\n");
40 
41   ValueToValueMapTy VMap;
42   auto ShouldCloneDefinition = [&F](const GlobalValue *GV) -> bool {
43     return GV == &F;
44   };
45   std::unique_ptr<Module> CM = CloneModule(*M, VMap, ShouldCloneDefinition);
46   Function *NewF = cast<Function>(VMap.lookup(&F));
47   assert(NewF && "Expected selected function to be cloned");
48 
49   LLVM_DEBUG(dbgs() << "Global DCE...\n");
50 
51   // Stop F itself from being pruned
52   GlobalValue::LinkageTypes OrigLinkage = NewF->getLinkage();
53   NewF->setLinkage(GlobalValue::ExternalLinkage);
54 
55   {
56     ModuleAnalysisManager MAM;
57     ModulePassManager MPM;
58 
59     PassInstrumentationCallbacks PIC;
60     MAM.registerPass([&] { return PassInstrumentationAnalysis(&PIC); });
61 
62     MPM.addPass(GlobalDCEPass());
63     MPM.addPass(StripDeadPrototypesPass());
64     MPM.run(*CM, MAM);
65   }
66 
67   // Restore old linkage
68   NewF->setLinkage(OrigLinkage);
69 
70   LLVM_DEBUG(dbgs() << "Write to file '" << Dumpfile << "'...\n");
71 
72   std::unique_ptr<ToolOutputFile> Out;
73   std::error_code EC;
74   Out.reset(new ToolOutputFile(Dumpfile, EC, sys::fs::OF_None));
75   if (EC) {
76     errs() << EC.message() << '\n';
77     return;
78   }
79 
80   CM->print(Out->os(), nullptr);
81   Out->keep();
82   LLVM_DEBUG(dbgs() << "Dump file " << Dumpfile << " written successfully\n");
83 }
84 
85 class DumpFunctionWrapperPass final : public FunctionPass {
86 private:
87   DumpFunctionWrapperPass(const DumpFunctionWrapperPass &) = delete;
88   const DumpFunctionWrapperPass &
89   operator=(const DumpFunctionWrapperPass &) = delete;
90 
91   std::string Suffix;
92 
93 public:
94   static char ID;
95 
96   explicit DumpFunctionWrapperPass() : FunctionPass(ID), Suffix("-dump") {}
97 
98   explicit DumpFunctionWrapperPass(std::string Suffix)
99       : FunctionPass(ID), Suffix(std::move(Suffix)) {}
100 
101   /// @name FunctionPass interface
102   //@{
103   void getAnalysisUsage(llvm::AnalysisUsage &AU) const override {
104     AU.setPreservesAll();
105   }
106 
107   bool runOnFunction(llvm::Function &F) override {
108     runDumpFunction(F, Suffix);
109     return false;
110   }
111   //@}
112 };
113 
114 char DumpFunctionWrapperPass::ID;
115 } // namespace
116 
117 FunctionPass *polly::createDumpFunctionWrapperPass(std::string Suffix) {
118   return new DumpFunctionWrapperPass(std::move(Suffix));
119 }
120 
121 llvm::PreservedAnalyses DumpFunctionPass::run(Function &F,
122                                               FunctionAnalysisManager &AM) {
123   runDumpFunction(F, Suffix);
124   return PreservedAnalyses::all();
125 }
126 
127 INITIALIZE_PASS_BEGIN(DumpFunctionWrapperPass, "polly-dump-function",
128                       "Polly - Dump Function", false, false)
129 INITIALIZE_PASS_END(DumpFunctionWrapperPass, "polly-dump-function",
130                     "Polly - Dump Function", false, false)
131