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 #include <optional>
31 using namespace llvm;
32
33 cl::OptionCategory AsCat("llvm-as Options");
34
35 static cl::opt<std::string> InputFilename(cl::Positional,
36 cl::desc("<input .llvm file>"),
37 cl::init("-"));
38
39 static cl::opt<std::string> OutputFilename("o",
40 cl::desc("Override output filename"),
41 cl::value_desc("filename"),
42 cl::cat(AsCat));
43
44 static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"),
45 cl::cat(AsCat));
46
47 static cl::opt<bool> DisableOutput("disable-output", cl::desc("Disable output"),
48 cl::init(false), cl::cat(AsCat));
49
50 static cl::opt<bool> EmitModuleHash("module-hash", cl::desc("Emit module hash"),
51 cl::init(false), cl::cat(AsCat));
52
53 static cl::opt<bool> DumpAsm("d", cl::desc("Print assembly as parsed"),
54 cl::Hidden, cl::cat(AsCat));
55
56 static cl::opt<bool>
57 DisableVerify("disable-verify", cl::Hidden,
58 cl::desc("Do not run verifier on input LLVM (dangerous!)"),
59 cl::cat(AsCat));
60
61 static cl::opt<bool> PreserveBitcodeUseListOrder(
62 "preserve-bc-uselistorder",
63 cl::desc("Preserve use-list order when writing LLVM bitcode."),
64 cl::init(true), cl::Hidden, cl::cat(AsCat));
65
66 static cl::opt<std::string> ClDataLayout("data-layout",
67 cl::desc("data layout string to use"),
68 cl::value_desc("layout-string"),
69 cl::init(""), cl::cat(AsCat));
70 extern cl::opt<bool> UseNewDbgInfoFormat;
71 extern bool WriteNewDbgInfoFormatToBitcode;
72
WriteOutputFile(const Module * M,const ModuleSummaryIndex * Index)73 static void WriteOutputFile(const Module *M, const ModuleSummaryIndex *Index) {
74 // Infer the output filename if needed.
75 if (OutputFilename.empty()) {
76 if (InputFilename == "-") {
77 OutputFilename = "-";
78 } else {
79 StringRef IFN = InputFilename;
80 OutputFilename = (IFN.ends_with(".ll") ? IFN.drop_back(3) : IFN).str();
81 OutputFilename += ".bc";
82 }
83 }
84
85 std::error_code EC;
86 std::unique_ptr<ToolOutputFile> Out(
87 new ToolOutputFile(OutputFilename, EC, sys::fs::OF_None));
88 if (EC) {
89 errs() << EC.message() << '\n';
90 exit(1);
91 }
92
93 if (Force || !CheckBitcodeOutputToConsole(Out->os())) {
94 const ModuleSummaryIndex *IndexToWrite = nullptr;
95 // Don't attempt to write a summary index unless it contains any entries or
96 // has non-zero flags. The latter is used to assemble dummy index files for
97 // skipping modules by distributed ThinLTO backends. Otherwise we get an empty
98 // summary section.
99 if (Index && (Index->begin() != Index->end() || Index->getFlags()))
100 IndexToWrite = Index;
101 if (!IndexToWrite || (M && (!M->empty() || !M->global_empty())))
102 // If we have a non-empty Module, then we write the Module plus
103 // any non-null Index along with it as a per-module Index.
104 // If both are empty, this will give an empty module block, which is
105 // the expected behavior.
106 WriteBitcodeToFile(*M, Out->os(), PreserveBitcodeUseListOrder,
107 IndexToWrite, EmitModuleHash);
108 else
109 // Otherwise, with an empty Module but non-empty Index, we write a
110 // combined index.
111 writeIndexToFile(*IndexToWrite, Out->os());
112 }
113
114 // Declare success.
115 Out->keep();
116 }
117
main(int argc,char ** argv)118 int main(int argc, char **argv) {
119 InitLLVM X(argc, argv);
120 cl::HideUnrelatedOptions(AsCat);
121 cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
122 LLVMContext Context;
123
124 // Parse the file now...
125 SMDiagnostic Err;
126 auto SetDataLayout = [](StringRef, StringRef) -> std::optional<std::string> {
127 if (ClDataLayout.empty())
128 return std::nullopt;
129 return ClDataLayout;
130 };
131 ParsedModuleAndIndex ModuleAndIndex;
132 if (DisableVerify) {
133 ModuleAndIndex = parseAssemblyFileWithIndexNoUpgradeDebugInfo(
134 InputFilename, Err, Context, nullptr, SetDataLayout);
135 } else {
136 ModuleAndIndex = parseAssemblyFileWithIndex(InputFilename, Err, Context,
137 nullptr, SetDataLayout);
138 }
139 std::unique_ptr<Module> M = std::move(ModuleAndIndex.Mod);
140 if (!M) {
141 Err.print(argv[0], errs());
142 return 1;
143 }
144
145 // Convert to new debug format if requested.
146 M->setIsNewDbgInfoFormat(UseNewDbgInfoFormat &&
147 WriteNewDbgInfoFormatToBitcode);
148 if (M->IsNewDbgInfoFormat)
149 M->removeDebugIntrinsicDeclarations();
150
151 std::unique_ptr<ModuleSummaryIndex> Index = std::move(ModuleAndIndex.Index);
152
153 if (!DisableVerify) {
154 std::string ErrorStr;
155 raw_string_ostream OS(ErrorStr);
156 if (verifyModule(*M, &OS)) {
157 errs() << argv[0]
158 << ": assembly parsed, but does not verify as correct!\n";
159 errs() << OS.str();
160 return 1;
161 }
162 // TODO: Implement and call summary index verifier.
163 }
164
165 if (DumpAsm) {
166 errs() << "Here's the assembly:\n" << *M;
167 if (Index.get() && Index->begin() != Index->end())
168 Index->print(errs());
169 }
170
171 if (!DisableOutput)
172 WriteOutputFile(M.get(), Index.get());
173
174 return 0;
175 }
176