xref: /llvm-project/llvm/tools/llvm-as/llvm-as.cpp (revision c00d81e6977cc98e0eea33d58847ffb17223635a)
1 //===--- llvm-as.cpp - The low-level LLVM assembler -----------------------===//
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 utility may be invoked in the following manner:
11 //   llvm-as --help         - Output information about command line switches
12 //   llvm-as [options]      - Read LLVM asm from stdin, write bitcode to stdout
13 //   llvm-as [options] x.ll - Read LLVM asm from the x.ll file, write bitcode
14 //                            to the x.bc file.
15 //
16 //===----------------------------------------------------------------------===//
17 
18 #include "llvm/AsmParser/Parser.h"
19 #include "llvm/Bitcode/BitcodeWriter.h"
20 #include "llvm/IR/LLVMContext.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/IR/Verifier.h"
23 #include "llvm/Support/CommandLine.h"
24 #include "llvm/Support/FileSystem.h"
25 #include "llvm/Support/ManagedStatic.h"
26 #include "llvm/Support/PrettyStackTrace.h"
27 #include "llvm/Support/Signals.h"
28 #include "llvm/Support/SourceMgr.h"
29 #include "llvm/Support/SystemUtils.h"
30 #include "llvm/Support/ToolOutputFile.h"
31 #include <memory>
32 using namespace llvm;
33 
34 static cl::opt<std::string> InputFilename(cl::Positional,
35                                           cl::desc("<input .llvm file>"),
36                                           cl::init("-"));
37 
38 static cl::opt<std::string> OutputFilename("o",
39                                            cl::desc("Override output filename"),
40                                            cl::value_desc("filename"));
41 
42 static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"));
43 
44 static cl::opt<bool> DisableOutput("disable-output", cl::desc("Disable output"),
45                                    cl::init(false));
46 
47 static cl::opt<bool> EmitModuleHash("module-hash", cl::desc("Emit module hash"),
48                                     cl::init(false));
49 
50 static cl::opt<bool> DumpAsm("d", cl::desc("Print assembly as parsed"),
51                              cl::Hidden);
52 
53 static cl::opt<bool>
54     DisableVerify("disable-verify", cl::Hidden,
55                   cl::desc("Do not run verifier on input LLVM (dangerous!)"));
56 
57 static cl::opt<bool> PreserveBitcodeUseListOrder(
58     "preserve-bc-uselistorder",
59     cl::desc("Preserve use-list order when writing LLVM bitcode."),
60     cl::init(true), cl::Hidden);
61 
62 static cl::opt<std::string> ClDataLayout("data-layout",
63                                          cl::desc("data layout string to use"),
64                                          cl::value_desc("layout-string"),
65                                          cl::init(""));
66 
67 static void WriteOutputFile(const Module *M) {
68   // Infer the output filename if needed.
69   if (OutputFilename.empty()) {
70     if (InputFilename == "-") {
71       OutputFilename = "-";
72     } else {
73       StringRef IFN = InputFilename;
74       OutputFilename = (IFN.endswith(".ll") ? IFN.drop_back(3) : IFN).str();
75       OutputFilename += ".bc";
76     }
77   }
78 
79   std::error_code EC;
80   std::unique_ptr<ToolOutputFile> Out(
81       new ToolOutputFile(OutputFilename, EC, sys::fs::F_None));
82   if (EC) {
83     errs() << EC.message() << '\n';
84     exit(1);
85   }
86 
87   if (Force || !CheckBitcodeOutputToConsole(Out->os(), true))
88     WriteBitcodeToFile(M, Out->os(), PreserveBitcodeUseListOrder, nullptr,
89                        EmitModuleHash);
90 
91   // Declare success.
92   Out->keep();
93 }
94 
95 int main(int argc, char **argv) {
96   // Print a stack trace if we signal out.
97   sys::PrintStackTraceOnErrorSignal(argv[0]);
98   PrettyStackTraceProgram X(argc, argv);
99   LLVMContext Context;
100   llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
101   cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
102 
103   // Parse the file now...
104   SMDiagnostic Err;
105   std::unique_ptr<Module> M = parseAssemblyFile(
106       InputFilename, Err, Context, nullptr, !DisableVerify, ClDataLayout);
107   if (!M.get()) {
108     Err.print(argv[0], errs());
109     return 1;
110   }
111 
112   if (!DisableVerify) {
113     std::string ErrorStr;
114     raw_string_ostream OS(ErrorStr);
115     if (verifyModule(*M.get(), &OS)) {
116       errs() << argv[0]
117              << ": assembly parsed, but does not verify as correct!\n";
118       errs() << OS.str();
119       return 1;
120     }
121   }
122 
123   if (DumpAsm)
124     errs() << "Here's the assembly:\n" << *M.get();
125 
126   if (!DisableOutput)
127     WriteOutputFile(M.get());
128 
129   return 0;
130 }
131