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

source code of llvm/tools/llvm-as/llvm-as.cpp