1 //===- BugDriver.h - Top-Level BugPoint class -------------------*- 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 // This class contains all of the shared state and information that is used by
10 // the BugPoint tool to track down errors in optimizations.  This class is the
11 // main driver class that invokes all sub-functionality.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_TOOLS_BUGPOINT_BUGDRIVER_H
16 #define LLVM_TOOLS_BUGPOINT_BUGDRIVER_H
17 
18 #include "llvm/IR/ValueMap.h"
19 #include "llvm/Support/Error.h"
20 #include "llvm/Support/FileSystem.h"
21 #include "llvm/Transforms/Utils/ValueMapper.h"
22 #include <memory>
23 #include <string>
24 #include <vector>
25 
26 namespace llvm {
27 
28 class Module;
29 class GlobalVariable;
30 class Function;
31 class BasicBlock;
32 class AbstractInterpreter;
33 class Instruction;
34 class LLVMContext;
35 
36 class CC;
37 
38 extern bool DisableSimplifyCFG;
39 
40 /// BugpointIsInterrupted - Set to true when the user presses ctrl-c.
41 ///
42 extern bool BugpointIsInterrupted;
43 
44 class BugDriver {
45   LLVMContext &Context;
46   const char *ToolName;            // argv[0] of bugpoint
47   std::string ReferenceOutputFile; // Name of `good' output file
48   std::unique_ptr<Module> Program; // The raw program, linked together
49   std::vector<std::string> PassesToRun;
50   AbstractInterpreter *Interpreter;     // How to run the program
51   AbstractInterpreter *SafeInterpreter; // To generate reference output, etc.
52   CC *cc;
53   bool run_find_bugs;
54   unsigned Timeout;
55   unsigned MemoryLimit;
56   bool UseValgrind;
57 
58   // FIXME: sort out public/private distinctions...
59   friend class ReducePassList;
60   friend class ReduceMisCodegenFunctions;
61 
62 public:
63   BugDriver(const char *toolname, bool find_bugs, unsigned timeout,
64             unsigned memlimit, bool use_valgrind, LLVMContext &ctxt);
65   ~BugDriver();
66 
67   const char *getToolName() const { return ToolName; }
68 
69   LLVMContext &getContext() const { return Context; }
70 
71   // Set up methods... these methods are used to copy information about the
72   // command line arguments into instance variables of BugDriver.
73   //
74   bool addSources(const std::vector<std::string> &FileNames);
75   void addPass(std::string p) { PassesToRun.push_back(std::move(p)); }
76   void setPassesToRun(const std::vector<std::string> &PTR) {
77     PassesToRun = PTR;
78   }
79   const std::vector<std::string> &getPassesToRun() const { return PassesToRun; }
80 
81   /// run - The top level method that is invoked after all of the instance
82   /// variables are set up from command line arguments. The \p as_child argument
83   /// indicates whether the driver is to run in parent mode or child mode.
84   ///
85   Error run();
86 
87   /// debugOptimizerCrash - This method is called when some optimizer pass
88   /// crashes on input.  It attempts to prune down the testcase to something
89   /// reasonable, and figure out exactly which pass is crashing.
90   ///
91   Error debugOptimizerCrash(const std::string &ID = "passes");
92 
93   /// debugCodeGeneratorCrash - This method is called when the code generator
94   /// crashes on an input.  It attempts to reduce the input as much as possible
95   /// while still causing the code generator to crash.
96   Error debugCodeGeneratorCrash();
97 
98   /// debugMiscompilation - This method is used when the passes selected are not
99   /// crashing, but the generated output is semantically different from the
100   /// input.
101   Error debugMiscompilation();
102 
103   /// compileSharedObject - This method creates a SharedObject from a given
104   /// BitcodeFile for debugging a code generator.
105   ///
106   Expected<std::string> compileSharedObject(const std::string &BitcodeFile);
107 
108   /// debugCodeGenerator - This method narrows down a module to a function or
109   /// set of functions, using the CBE as a ``safe'' code generator for other
110   /// functions that are not under consideration.
111   Error debugCodeGenerator();
112 
113   /// isExecutingJIT - Returns true if bugpoint is currently testing the JIT
114   ///
115   bool isExecutingJIT();
116 
117   Module &getProgram() const { return *Program; }
118 
119   /// Set the current module to the specified module, returning the old one.
120   std::unique_ptr<Module> swapProgramIn(std::unique_ptr<Module> M);
121 
122   AbstractInterpreter *switchToSafeInterpreter() {
123     AbstractInterpreter *Old = Interpreter;
124     Interpreter = (AbstractInterpreter *)SafeInterpreter;
125     return Old;
126   }
127 
128   void switchToInterpreter(AbstractInterpreter *AI) { Interpreter = AI; }
129 
130   /// If we reduce or update the program somehow, call this method to update
131   /// bugdriver with it.  This deletes the old module and sets the specified one
132   /// as the current program.
133   void setNewProgram(std::unique_ptr<Module> M);
134 
135   /// Try to compile the specified module. This is used for code generation
136   /// crash testing.
137   Error compileProgram(Module &M) const;
138 
139   /// This method runs "Program", capturing the output of the program to a file.
140   /// A recommended filename may be optionally specified.
141   Expected<std::string> executeProgram(const Module &Program,
142                                        std::string OutputFilename,
143                                        std::string Bitcode,
144                                        const std::string &SharedObjects,
145                                        AbstractInterpreter *AI) const;
146 
147   /// Used to create reference output with the "safe" backend, if reference
148   /// output is not provided.  If there is a problem with the code generator
149   /// (e.g., llc crashes), this will return false and set Error.
150   Expected<std::string>
151   executeProgramSafely(const Module &Program,
152                        const std::string &OutputFile) const;
153 
154   /// Calls compileProgram and then records the output into ReferenceOutputFile.
155   /// Returns true if reference file created, false otherwise. Note:
156   /// initializeExecutionEnvironment should be called BEFORE this function.
157   Error createReferenceFile(Module &M, const std::string &Filename =
158                                            "bugpoint.reference.out-%%%%%%%");
159 
160   /// This method executes the specified module and diffs the output against the
161   /// file specified by ReferenceOutputFile.  If the output is different, 1 is
162   /// returned.  If there is a problem with the code generator (e.g., llc
163   /// crashes), this will return -1 and set Error.
164   Expected<bool> diffProgram(const Module &Program,
165                              const std::string &BitcodeFile = "",
166                              const std::string &SharedObj = "",
167                              bool RemoveBitcode = false) const;
168 
169   /// This function is used to output M to a file named "bugpoint-ID.bc".
170   void EmitProgressBitcode(const Module &M, const std::string &ID,
171                            bool NoFlyer = false) const;
172 
173   /// This method clones the current Program and deletes the specified
174   /// instruction from the cloned module.  It then runs a series of cleanup
175   /// passes (ADCE and SimplifyCFG) to eliminate any code which depends on the
176   /// value. The modified module is then returned.
177   ///
178   std::unique_ptr<Module> deleteInstructionFromProgram(const Instruction *I,
179                                                        unsigned Simp);
180 
181   /// This method clones the current Program and performs a series of cleanups
182   /// intended to get rid of extra cruft on the module. If the
183   /// MayModifySemantics argument is true, then the cleanups is allowed to
184   /// modify how the code behaves.
185   ///
186   std::unique_ptr<Module> performFinalCleanups(std::unique_ptr<Module> M,
187                                                bool MayModifySemantics = false);
188 
189   /// Given a module, extract up to one loop from it into a new function. This
190   /// returns null if there are no extractable loops in the program or if the
191   /// loop extractor crashes.
192   std::unique_ptr<Module> extractLoop(Module *M);
193 
194   /// Extract all but the specified basic blocks into their own functions. The
195   /// only detail is that M is actually a module cloned from the one the BBs are
196   /// in, so some mapping needs to be performed. If this operation fails for
197   /// some reason (ie the implementation is buggy), this function should return
198   /// null, otherwise it returns a new Module.
199   std::unique_ptr<Module>
200   extractMappedBlocksFromModule(const std::vector<BasicBlock *> &BBs,
201                                 Module *M);
202 
203   /// Carefully run the specified set of pass on the specified/ module,
204   /// returning the transformed module on success, or a null pointer on failure.
205   std::unique_ptr<Module> runPassesOn(Module *M,
206                                       const std::vector<std::string> &Passes,
207                                       ArrayRef<std::string> ExtraArgs = {});
208 
209   /// runPasses - Run the specified passes on Program, outputting a bitcode
210   /// file and writting the filename into OutputFile if successful.  If the
211   /// optimizations fail for some reason (optimizer crashes), return true,
212   /// otherwise return false.  If DeleteOutput is set to true, the bitcode is
213   /// deleted on success, and the filename string is undefined.  This prints to
214   /// outs() a single line message indicating whether compilation was successful
215   /// or failed, unless Quiet is set.  ExtraArgs specifies additional arguments
216   /// to pass to the child bugpoint instance.
217   ///
218   bool runPasses(Module &Program, const std::vector<std::string> &PassesToRun,
219                  std::string &OutputFilename, bool DeleteOutput = false,
220                  bool Quiet = false,
221                  ArrayRef<std::string> ExtraArgs = {}) const;
222 
223   /// runPasses - Just like the method above, but this just returns true or
224   /// false indicating whether or not the optimizer crashed on the specified
225   /// input (true = crashed).  Does not produce any output.
226   ///
227   bool runPasses(Module &M, const std::vector<std::string> &PassesToRun) const {
228     std::string Filename;
229     return runPasses(M, PassesToRun, Filename, true);
230   }
231 
232   /// Take the specified pass list and create different combinations of passes
233   /// to compile the program with. Compile the program with each set and mark
234   /// test to see if it compiled correctly. If the passes compiled correctly
235   /// output nothing and rearrange the passes into a new order. If the passes
236   /// did not compile correctly, output the command required to recreate the
237   /// failure.
238   Error runManyPasses(const std::vector<std::string> &AllPasses);
239 
240   /// This writes the current "Program" to the named bitcode file.  If an error
241   /// occurs, true is returned.
242   bool writeProgramToFile(const std::string &Filename, const Module &M) const;
243   bool writeProgramToFile(const std::string &Filename, int FD,
244                           const Module &M) const;
245   bool writeProgramToFile(int FD, const Module &M) const;
246 
247 private:
248   /// initializeExecutionEnvironment - This method is used to set up the
249   /// environment for executing LLVM programs.
250   ///
251   Error initializeExecutionEnvironment();
252 };
253 
254 struct DiscardTemp {
255   sys::fs::TempFile &File;
256   ~DiscardTemp();
257 };
258 
259 ///  Given a bitcode or assembly input filename, parse and return it, or return
260 ///  null if not possible.
261 ///
262 std::unique_ptr<Module> parseInputFile(StringRef InputFilename,
263                                        LLVMContext &ctxt);
264 
265 /// getPassesString - Turn a list of passes into a string which indicates the
266 /// command line options that must be passed to add the passes.
267 ///
268 std::string getPassesString(const std::vector<std::string> &Passes);
269 
270 /// PrintFunctionList - prints out list of problematic functions
271 ///
272 void PrintFunctionList(const std::vector<Function *> &Funcs);
273 
274 /// PrintGlobalVariableList - prints out list of problematic global variables
275 ///
276 void PrintGlobalVariableList(const std::vector<GlobalVariable *> &GVs);
277 
278 // DeleteGlobalInitializer - "Remove" the global variable by deleting its
279 // initializer, making it external.
280 //
281 void DeleteGlobalInitializer(GlobalVariable *GV);
282 
283 // DeleteFunctionBody - "Remove" the function by deleting all of it's basic
284 // blocks, making it external.
285 //
286 void DeleteFunctionBody(Function *F);
287 
288 /// Given a module and a list of functions in the module, split the functions
289 /// OUT of the specified module, and place them in the new module.
290 std::unique_ptr<Module>
291 SplitFunctionsOutOfModule(Module *M, const std::vector<Function *> &F,
292                           ValueToValueMapTy &VMap);
293 
294 } // End llvm namespace
295 
296 #endif
297