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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/IR/LLVMContext.h"
19 #include "llvm/AsmParser/Parser.h"
20 #include "llvm/Bitcode/ReaderWriter.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>
35 InputFilename(cl::Positional, cl::desc("<input .llvm file>"), cl::init("-"));
36 
37 static cl::opt<std::string>
38 OutputFilename("o", cl::desc("Override output filename"),
39                cl::value_desc("filename"));
40 
41 static cl::opt<bool>
42 Force("f", cl::desc("Enable binary output on terminals"));
43 
44 static cl::opt<bool>
45 DisableOutput("disable-output", cl::desc("Disable output"), cl::init(false));
46 
47 static cl::opt<bool>
48 DumpAsm("d", cl::desc("Print assembly as parsed"), cl::Hidden);
49 
50 static cl::opt<bool>
51 DisableVerify("disable-verify", cl::Hidden,
52               cl::desc("Do not run verifier on input LLVM (dangerous!)"));
53 
54 static cl::opt<bool> PreserveBitcodeUseListOrder(
55     "preserve-bc-uselistorder",
56     cl::desc("Preserve use-list order when writing LLVM bitcode."),
57     cl::init(true), cl::Hidden);
58 
WriteOutputFile(const Module * M)59 static void WriteOutputFile(const Module *M) {
60   // Infer the output filename if needed.
61   if (OutputFilename.empty()) {
62     if (InputFilename == "-") {
63       OutputFilename = "-";
64     } else {
65       std::string IFN = InputFilename;
66       int Len = IFN.length();
67       if (IFN[Len-3] == '.' && IFN[Len-2] == 'l' && IFN[Len-1] == 'l') {
68         // Source ends in .ll
69         OutputFilename = std::string(IFN.begin(), IFN.end()-3);
70       } else {
71         OutputFilename = IFN;   // Append a .bc to it
72       }
73       OutputFilename += ".bc";
74     }
75   }
76 
77   std::error_code EC;
78   std::unique_ptr<tool_output_file> Out(
79       new tool_output_file(OutputFilename, EC, sys::fs::F_None));
80   if (EC) {
81     errs() << EC.message() << '\n';
82     exit(1);
83   }
84 
85   if (Force || !CheckBitcodeOutputToConsole(Out->os(), true))
86     WriteBitcodeToFile(M, Out->os(), PreserveBitcodeUseListOrder);
87 
88   // Declare success.
89   Out->keep();
90 }
91 
main(int argc,char ** argv)92 int main(int argc, char **argv) {
93   // Print a stack trace if we signal out.
94   sys::PrintStackTraceOnErrorSignal();
95   PrettyStackTraceProgram X(argc, argv);
96   LLVMContext &Context = getGlobalContext();
97   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
98   cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
99 
100   // Parse the file now...
101   SMDiagnostic Err;
102   std::unique_ptr<Module> M = parseAssemblyFile(InputFilename, Err, Context);
103   if (!M.get()) {
104     Err.print(argv[0], errs());
105     return 1;
106   }
107 
108   if (!DisableVerify) {
109     std::string ErrorStr;
110     raw_string_ostream OS(ErrorStr);
111     if (verifyModule(*M.get(), &OS)) {
112       errs() << argv[0]
113              << ": assembly parsed, but does not verify as correct!\n";
114       errs() << OS.str();
115       return 1;
116     }
117   }
118 
119   if (DumpAsm) errs() << "Here's the assembly:\n" << *M.get();
120 
121   if (!DisableOutput)
122     WriteOutputFile(M.get());
123 
124   return 0;
125 }
126