1//===- OptimizerDriver.cpp - Allow BugPoint to run passes safely ----------===//
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 defines an interface that allows bugpoint to run various passes
10// without the threat of a buggy pass corrupting bugpoint (of course, bugpoint
11// may have its own bugs, but that's another story...). It achieves this by
12// forking a copy of itself and having the child process do the optimizations.
13// If this client dies, we can always fork a new one. :)
14//
15//===----------------------------------------------------------------------===//
16
17#include "BugDriver.h"
18#include "ToolRunner.h"
19#include "llvm/Bitcode/BitcodeWriter.h"
20#include "llvm/IR/DataLayout.h"
21#include "llvm/IR/Module.h"
22#include "llvm/Support/CommandLine.h"
23#include "llvm/Support/Debug.h"
24#include "llvm/Support/FileUtilities.h"
25#include "llvm/Support/Path.h"
26#include "llvm/Support/Program.h"
27#include "llvm/Support/ToolOutputFile.h"
28
29#define DONT_GET_PLUGIN_LOADER_OPTION
30#include "llvm/Support/PluginLoader.h"
31
32
33using namespace llvm;
34
35#define DEBUG_TYPE "bugpoint"
36
37namespace llvm {
38extern cl::opt<std::string> OutputPrefix;
39}
40
41static cl::opt<bool> PreserveBitcodeUseListOrder(
42 "preserve-bc-uselistorder",
43 cl::desc("Preserve use-list order when writing LLVM bitcode."),
44 cl::init(Val: true), cl::Hidden);
45
46static cl::opt<std::string>
47 OptCmd("opt-command", cl::init(Val: ""),
48 cl::desc("Path to opt. (default: search path "
49 "for 'opt'.)"));
50
51/// This writes the current "Program" to the named bitcode file. If an error
52/// occurs, true is returned.
53static bool writeProgramToFileAux(ToolOutputFile &Out, const Module &M) {
54 WriteBitcodeToFile(M, Out&: Out.os(), ShouldPreserveUseListOrder: PreserveBitcodeUseListOrder);
55 Out.os().close();
56 if (!Out.os().has_error()) {
57 Out.keep();
58 return false;
59 }
60 return true;
61}
62
63bool BugDriver::writeProgramToFile(const std::string &Filename, int FD,
64 const Module &M) const {
65 ToolOutputFile Out(Filename, FD);
66 return writeProgramToFileAux(Out, M);
67}
68
69bool BugDriver::writeProgramToFile(int FD, const Module &M) const {
70 raw_fd_ostream OS(FD, /*shouldClose*/ false);
71 WriteBitcodeToFile(M, Out&: OS, ShouldPreserveUseListOrder: PreserveBitcodeUseListOrder);
72 OS.flush();
73 if (!OS.has_error())
74 return false;
75 OS.clear_error();
76 return true;
77}
78
79bool BugDriver::writeProgramToFile(const std::string &Filename,
80 const Module &M) const {
81 std::error_code EC;
82 ToolOutputFile Out(Filename, EC, sys::fs::OF_None);
83 if (!EC)
84 return writeProgramToFileAux(Out, M);
85 return true;
86}
87
88/// This function is used to output the current Program to a file named
89/// "bugpoint-ID.bc".
90void BugDriver::EmitProgressBitcode(const Module &M, const std::string &ID,
91 bool NoFlyer) const {
92 // Output the input to the current pass to a bitcode file, emit a message
93 // telling the user how to reproduce it: opt -foo blah.bc
94 //
95 std::string Filename = OutputPrefix + "-" + ID + ".bc";
96 if (writeProgramToFile(Filename, M)) {
97 errs() << "Error opening file '" << Filename << "' for writing!\n";
98 return;
99 }
100
101 outs() << "Emitted bitcode to '" << Filename << "'\n";
102 if (NoFlyer || PassesToRun.empty())
103 return;
104 outs() << "\n*** You can reproduce the problem with: ";
105 if (UseValgrind)
106 outs() << "valgrind ";
107 outs() << "opt " << Filename;
108 for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
109 outs() << " -load " << PluginLoader::getPlugin(num: i);
110 }
111 outs() << " " << getPassesString(Passes: PassesToRun) << "\n";
112}
113
114static cl::opt<bool> SilencePasses(
115 "silence-passes",
116 cl::desc("Suppress output of running passes (both stdout and stderr)"));
117
118static cl::list<std::string> OptArgs("opt-args", cl::Positional,
119 cl::desc("<opt arguments>..."),
120 cl::PositionalEatsArgs);
121
122/// runPasses - Run the specified passes on Program, outputting a bitcode file
123/// and writing the filename into OutputFile if successful. If the
124/// optimizations fail for some reason (optimizer crashes), return true,
125/// otherwise return false. If DeleteOutput is set to true, the bitcode is
126/// deleted on success, and the filename string is undefined. This prints to
127/// outs() a single line message indicating whether compilation was successful
128/// or failed.
129///
130bool BugDriver::runPasses(Module &Program,
131 const std::vector<std::string> &Passes,
132 std::string &OutputFilename, bool DeleteOutput,
133 bool Quiet, ArrayRef<std::string> ExtraArgs) const {
134 // setup the output file name
135 outs().flush();
136 SmallString<128> UniqueFilename;
137 std::error_code EC = sys::fs::createUniqueFile(
138 Model: OutputPrefix + "-output-%%%%%%%.bc", ResultPath&: UniqueFilename);
139 if (EC) {
140 errs() << getToolName()
141 << ": Error making unique filename: " << EC.message() << "\n";
142 return true;
143 }
144 OutputFilename = std::string(UniqueFilename);
145
146 // set up the input file name
147 Expected<sys::fs::TempFile> Temp =
148 sys::fs::TempFile::create(Model: OutputPrefix + "-input-%%%%%%%.bc");
149 if (!Temp) {
150 errs() << getToolName()
151 << ": Error making unique filename: " << toString(E: Temp.takeError())
152 << "\n";
153 return true;
154 }
155 DiscardTemp Discard{.File: *Temp};
156 raw_fd_ostream OS(Temp->FD, /*shouldClose*/ false);
157
158 WriteBitcodeToFile(M: Program, Out&: OS, ShouldPreserveUseListOrder: PreserveBitcodeUseListOrder);
159 OS.flush();
160 if (OS.has_error()) {
161 errs() << "Error writing bitcode file: " << Temp->TmpName << "\n";
162 OS.clear_error();
163 return true;
164 }
165
166 std::string tool = OptCmd;
167 if (OptCmd.empty()) {
168 if (ErrorOr<std::string> Path =
169 FindProgramByName(ExeName: "opt", Argv0: getToolName(), MainAddr: &OutputPrefix))
170 tool = *Path;
171 else
172 errs() << Path.getError().message() << "\n";
173 }
174 if (tool.empty()) {
175 errs() << "Cannot find `opt' in PATH!\n";
176 return true;
177 }
178 if (!sys::fs::exists(Path: tool)) {
179 errs() << "Specified `opt' binary does not exist: " << tool << "\n";
180 return true;
181 }
182
183 std::string Prog;
184 if (UseValgrind) {
185 if (ErrorOr<std::string> Path = sys::findProgramByName(Name: "valgrind"))
186 Prog = *Path;
187 else
188 errs() << Path.getError().message() << "\n";
189 } else
190 Prog = tool;
191 if (Prog.empty()) {
192 errs() << "Cannot find `valgrind' in PATH!\n";
193 return true;
194 }
195
196 // setup the child process' arguments
197 SmallVector<StringRef, 8> Args;
198 if (UseValgrind) {
199 Args.push_back(Elt: "valgrind");
200 Args.push_back(Elt: "--error-exitcode=1");
201 Args.push_back(Elt: "-q");
202 Args.push_back(Elt: tool);
203 } else
204 Args.push_back(Elt: tool);
205
206 llvm::append_range(C&: Args, R&: OptArgs);
207 // Pin to legacy PM since bugpoint has lots of infra and hacks revolving
208 // around the legacy PM.
209 Args.push_back(Elt: "-bugpoint-enable-legacy-pm");
210 Args.push_back(Elt: "-disable-symbolication");
211 Args.push_back(Elt: "-o");
212 Args.push_back(Elt: OutputFilename);
213 std::vector<std::string> pass_args;
214 for (unsigned i = 0, e = PluginLoader::getNumPlugins(); i != e; ++i) {
215 pass_args.push_back(x: std::string("-load"));
216 pass_args.push_back(x: PluginLoader::getPlugin(num: i));
217 }
218 for (std::vector<std::string>::const_iterator I = Passes.begin(),
219 E = Passes.end();
220 I != E; ++I)
221 pass_args.push_back(x: std::string("-") + (*I));
222 for (std::vector<std::string>::const_iterator I = pass_args.begin(),
223 E = pass_args.end();
224 I != E; ++I)
225 Args.push_back(Elt: *I);
226 Args.push_back(Elt: Temp->TmpName);
227 Args.append(in_start: ExtraArgs.begin(), in_end: ExtraArgs.end());
228
229 LLVM_DEBUG(errs() << "\nAbout to run:\t";
230 for (unsigned i = 0, e = Args.size() - 1; i != e; ++i) errs()
231 << " " << Args[i];
232 errs() << "\n";);
233
234 std::optional<StringRef> Redirects[3] = {std::nullopt, std::nullopt,
235 std::nullopt};
236 // Redirect stdout and stderr to nowhere if SilencePasses is given.
237 if (SilencePasses) {
238 Redirects[1] = "";
239 Redirects[2] = "";
240 }
241
242 std::string ErrMsg;
243 int result = sys::ExecuteAndWait(Program: Prog, Args, Env: std::nullopt, Redirects, SecondsToWait: Timeout,
244 MemoryLimit, ErrMsg: &ErrMsg);
245
246 // If we are supposed to delete the bitcode file or if the passes crashed,
247 // remove it now. This may fail if the file was never created, but that's ok.
248 if (DeleteOutput || result != 0)
249 sys::fs::remove(path: OutputFilename);
250
251 if (!Quiet) {
252 if (result == 0)
253 outs() << "Success!\n";
254 else if (result > 0)
255 outs() << "Exited with error code '" << result << "'\n";
256 else if (result < 0) {
257 if (result == -1)
258 outs() << "Execute failed: " << ErrMsg << "\n";
259 else
260 outs() << "Crashed: " << ErrMsg << "\n";
261 }
262 if (result & 0x01000000)
263 outs() << "Dumped core\n";
264 }
265
266 // Was the child successful?
267 return result != 0;
268}
269
270std::unique_ptr<Module>
271BugDriver::runPassesOn(Module *M, const std::vector<std::string> &Passes,
272 ArrayRef<std::string> ExtraArgs) {
273 std::string BitcodeResult;
274 if (runPasses(Program&: *M, Passes, OutputFilename&: BitcodeResult, DeleteOutput: false /*delete*/, Quiet: true /*quiet*/,
275 ExtraArgs)) {
276 return nullptr;
277 }
278
279 std::unique_ptr<Module> Ret = parseInputFile(InputFilename: BitcodeResult, ctxt&: Context);
280 if (!Ret) {
281 errs() << getToolName() << ": Error reading bitcode file '" << BitcodeResult
282 << "'!\n";
283 exit(status: 1);
284 }
285 sys::fs::remove(path: BitcodeResult);
286 return Ret;
287}
288