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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/Analysis/Verifier.h"
20 #include "llvm/Assembly/Parser.h"
21 #include "llvm/Bitcode/ReaderWriter.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/Support/CommandLine.h"
24 #include "llvm/Support/ManagedStatic.h"
25 #include "llvm/Support/PrettyStackTrace.h"
26 #include "llvm/Support/Signals.h"
27 #include "llvm/Support/SourceMgr.h"
28 #include "llvm/Support/SystemUtils.h"
29 #include "llvm/Support/ToolOutputFile.h"
30 #include <memory>
31 using namespace llvm;
32 
33 static cl::opt<std::string>
34 InputFilename(cl::Positional, cl::desc("<input .llvm file>"), cl::init("-"));
35 
36 static cl::opt<std::string>
37 OutputFilename("o", cl::desc("Override output filename"),
38                cl::value_desc("filename"));
39 
40 static cl::opt<bool>
41 Force("f", cl::desc("Enable binary output on terminals"));
42 
43 static cl::opt<bool>
44 DisableOutput("disable-output", cl::desc("Disable output"), cl::init(false));
45 
46 static cl::opt<bool>
47 DumpAsm("d", cl::desc("Print assembly as parsed"), cl::Hidden);
48 
49 static cl::opt<bool>
50 DisableVerify("disable-verify", cl::Hidden,
51               cl::desc("Do not run verifier on input LLVM (dangerous!)"));
52 
WriteOutputFile(const Module * M)53 static void WriteOutputFile(const Module *M) {
54   // Infer the output filename if needed.
55   if (OutputFilename.empty()) {
56     if (InputFilename == "-") {
57       OutputFilename = "-";
58     } else {
59       std::string IFN = InputFilename;
60       int Len = IFN.length();
61       if (IFN[Len-3] == '.' && IFN[Len-2] == 'l' && IFN[Len-1] == 'l') {
62         // Source ends in .ll
63         OutputFilename = std::string(IFN.begin(), IFN.end()-3);
64       } else {
65         OutputFilename = IFN;   // Append a .bc to it
66       }
67       OutputFilename += ".bc";
68     }
69   }
70 
71   std::string ErrorInfo;
72   OwningPtr<tool_output_file> Out(new tool_output_file(
73       OutputFilename.c_str(), ErrorInfo, sys::fs::F_Binary));
74   if (!ErrorInfo.empty()) {
75     errs() << ErrorInfo << '\n';
76     exit(1);
77   }
78 
79   if (Force || !CheckBitcodeOutputToConsole(Out->os(), true))
80     WriteBitcodeToFile(M, Out->os());
81 
82   // Declare success.
83   Out->keep();
84 }
85 
main(int argc,char ** argv)86 int main(int argc, char **argv) {
87   // Print a stack trace if we signal out.
88   sys::PrintStackTraceOnErrorSignal();
89   PrettyStackTraceProgram X(argc, argv);
90   LLVMContext &Context = getGlobalContext();
91   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
92   cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
93 
94   // Parse the file now...
95   SMDiagnostic Err;
96   OwningPtr<Module> M(ParseAssemblyFile(InputFilename, Err, Context));
97   if (M.get() == 0) {
98     Err.print(argv[0], errs());
99     return 1;
100   }
101 
102   if (!DisableVerify) {
103     std::string Err;
104     if (verifyModule(*M.get(), ReturnStatusAction, &Err)) {
105       errs() << argv[0]
106              << ": assembly parsed, but does not verify as correct!\n";
107       errs() << Err;
108       return 1;
109     }
110   }
111 
112   if (DumpAsm) errs() << "Here's the assembly:\n" << *M.get();
113 
114   if (!DisableOutput)
115     WriteOutputFile(M.get());
116 
117   return 0;
118 }
119