1 //===--- llvm-as.cpp - The low-level LLVM assembler -----------------------===//
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 utility may be invoked in the following manner:
10 // llvm-as --help - Output information about command line switches
11 // llvm-as [options] - Read LLVM asm from stdin, write bitcode to stdout
12 // llvm-as [options] x.ll - Read LLVM asm from the x.ll file, write bitcode
13 // to the x.bc file.
14 //
15 //===----------------------------------------------------------------------===//
16
17 #include "llvm/AsmParser/Parser.h"
18 #include "llvm/Bitcode/BitcodeWriter.h"
19 #include "llvm/IR/LLVMContext.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/IR/ModuleSummaryIndex.h"
22 #include "llvm/IR/Verifier.h"
23 #include "llvm/Support/CommandLine.h"
24 #include "llvm/Support/FileSystem.h"
25 #include "llvm/Support/InitLLVM.h"
26 #include "llvm/Support/SourceMgr.h"
27 #include "llvm/Support/SystemUtils.h"
28 #include "llvm/Support/ToolOutputFile.h"
29 #include <memory>
30 using namespace llvm;
31
32 cl::OptionCategory AsCat("llvm-as Options");
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 cl::cat(AsCat));
42
43 static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"),
44 cl::cat(AsCat));
45
46 static cl::opt<bool> DisableOutput("disable-output", cl::desc("Disable output"),
47 cl::init(false), cl::cat(AsCat));
48
49 static cl::opt<bool> EmitModuleHash("module-hash", cl::desc("Emit module hash"),
50 cl::init(false), cl::cat(AsCat));
51
52 static cl::opt<bool> DumpAsm("d", cl::desc("Print assembly as parsed"),
53 cl::Hidden, cl::cat(AsCat));
54
55 static cl::opt<bool>
56 DisableVerify("disable-verify", cl::Hidden,
57 cl::desc("Do not run verifier on input LLVM (dangerous!)"),
58 cl::cat(AsCat));
59
60 static cl::opt<bool> PreserveBitcodeUseListOrder(
61 "preserve-bc-uselistorder",
62 cl::desc("Preserve use-list order when writing LLVM bitcode."),
63 cl::init(true), cl::Hidden, cl::cat(AsCat));
64
65 static cl::opt<std::string> ClDataLayout("data-layout",
66 cl::desc("data layout string to use"),
67 cl::value_desc("layout-string"),
68 cl::init(""), cl::cat(AsCat));
69
WriteOutputFile(const Module * M,const ModuleSummaryIndex * Index)70 static void WriteOutputFile(const Module *M, const ModuleSummaryIndex *Index) {
71 // Infer the output filename if needed.
72 if (OutputFilename.empty()) {
73 if (InputFilename == "-") {
74 OutputFilename = "-";
75 } else {
76 StringRef IFN = InputFilename;
77 OutputFilename = (IFN.endswith(".ll") ? IFN.drop_back(3) : IFN).str();
78 OutputFilename += ".bc";
79 }
80 }
81
82 std::error_code EC;
83 std::unique_ptr<ToolOutputFile> Out(
84 new ToolOutputFile(OutputFilename, EC, sys::fs::OF_None));
85 if (EC) {
86 errs() << EC.message() << '\n';
87 exit(1);
88 }
89
90 if (Force || !CheckBitcodeOutputToConsole(Out->os())) {
91 const ModuleSummaryIndex *IndexToWrite = nullptr;
92 // Don't attempt to write a summary index unless it contains any entries or
93 // has non-zero flags. The latter is used to assemble dummy index files for
94 // skipping modules by distributed ThinLTO backends. Otherwise we get an empty
95 // summary section.
96 if (Index && (Index->begin() != Index->end() || Index->getFlags()))
97 IndexToWrite = Index;
98 if (!IndexToWrite || (M && (!M->empty() || !M->global_empty())))
99 // If we have a non-empty Module, then we write the Module plus
100 // any non-null Index along with it as a per-module Index.
101 // If both are empty, this will give an empty module block, which is
102 // the expected behavior.
103 WriteBitcodeToFile(*M, Out->os(), PreserveBitcodeUseListOrder,
104 IndexToWrite, EmitModuleHash);
105 else
106 // Otherwise, with an empty Module but non-empty Index, we write a
107 // combined index.
108 writeIndexToFile(*IndexToWrite, Out->os());
109 }
110
111 // Declare success.
112 Out->keep();
113 }
114
main(int argc,char ** argv)115 int main(int argc, char **argv) {
116 InitLLVM X(argc, argv);
117 cl::HideUnrelatedOptions(AsCat);
118 cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
119 LLVMContext Context;
120
121 // Parse the file now...
122 SMDiagnostic Err;
123 auto SetDataLayout = [](StringRef) -> Optional<std::string> {
124 if (ClDataLayout.empty())
125 return None;
126 return ClDataLayout;
127 };
128 ParsedModuleAndIndex ModuleAndIndex;
129 if (DisableVerify) {
130 ModuleAndIndex = parseAssemblyFileWithIndexNoUpgradeDebugInfo(
131 InputFilename, Err, Context, nullptr, SetDataLayout);
132 } else {
133 ModuleAndIndex = parseAssemblyFileWithIndex(InputFilename, Err, Context,
134 nullptr, SetDataLayout);
135 }
136 std::unique_ptr<Module> M = std::move(ModuleAndIndex.Mod);
137 if (!M.get()) {
138 Err.print(argv[0], errs());
139 return 1;
140 }
141 std::unique_ptr<ModuleSummaryIndex> Index = std::move(ModuleAndIndex.Index);
142
143 if (!DisableVerify) {
144 std::string ErrorStr;
145 raw_string_ostream OS(ErrorStr);
146 if (verifyModule(*M.get(), &OS)) {
147 errs() << argv[0]
148 << ": assembly parsed, but does not verify as correct!\n";
149 errs() << OS.str();
150 return 1;
151 }
152 // TODO: Implement and call summary index verifier.
153 }
154
155 if (DumpAsm) {
156 errs() << "Here's the assembly:\n" << *M.get();
157 if (Index.get() && Index->begin() != Index->end())
158 Index->print(errs());
159 }
160
161 if (!DisableOutput)
162 WriteOutputFile(M.get(), Index.get());
163
164 return 0;
165 }
166