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
33static cl::OptionCategory AsCat("llvm-as Options");
34
35static cl::opt<std::string>
36 InputFilename(cl::Positional, cl::desc("<input .ll file>"), cl::init(Val: "-"));
37
38static cl::opt<std::string> OutputFilename("o",
39 cl::desc("Override output filename"),
40 cl::value_desc("filename"),
41 cl::cat(AsCat));
42
43static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"),
44 cl::cat(AsCat));
45
46static cl::opt<bool> DisableOutput("disable-output", cl::desc("Disable output"),
47 cl::init(Val: false), cl::cat(AsCat));
48
49static cl::opt<bool> EmitModuleHash("module-hash", cl::desc("Emit module hash"),
50 cl::init(Val: false), cl::cat(AsCat));
51
52static cl::opt<bool> DumpAsm("d", cl::desc("Print assembly as parsed"),
53 cl::Hidden, cl::cat(AsCat));
54
55static 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
60static cl::opt<bool> PreserveBitcodeUseListOrder(
61 "preserve-bc-uselistorder",
62 cl::desc("Preserve use-list order when writing LLVM bitcode."),
63 cl::init(Val: true), cl::Hidden, cl::cat(AsCat));
64
65static cl::opt<std::string> ClDataLayout("data-layout",
66 cl::desc("data layout string to use"),
67 cl::value_desc("layout-string"),
68 cl::init(Val: ""), cl::cat(AsCat));
69
70static 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.ends_with(Suffix: ".ll") ? IFN.drop_back(N: 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(status: 1);
88 }
89
90 if (Force || !CheckBitcodeOutputToConsole(stream_to_check&: 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: *M, Out&: Out->os(), ShouldPreserveUseListOrder: PreserveBitcodeUseListOrder,
104 Index: IndexToWrite, GenerateHash: EmitModuleHash);
105 else
106 // Otherwise, with an empty Module but non-empty Index, we write a
107 // combined index.
108 writeIndexToFile(Index: *IndexToWrite, Out&: Out->os());
109 }
110
111 // Declare success.
112 Out->keep();
113}
114
115int main(int argc, char **argv) {
116 InitLLVM X(argc, argv);
117 cl::HideUnrelatedOptions(Category&: AsCat);
118 cl::ParseCommandLineOptions(argc, argv, Overview: "llvm .ll -> .bc assembler\n");
119 LLVMContext Context;
120
121 // Parse the file now...
122 SMDiagnostic Err;
123 auto SetDataLayout = [](StringRef, StringRef) -> std::optional<std::string> {
124 if (ClDataLayout.empty())
125 return std::nullopt;
126 return ClDataLayout;
127 };
128 ParsedModuleAndIndex ModuleAndIndex;
129 if (DisableVerify) {
130 ModuleAndIndex = parseAssemblyFileWithIndexNoUpgradeDebugInfo(
131 Filename: InputFilename, Err, Context, Slots: nullptr, DataLayoutCallback: SetDataLayout);
132 } else {
133 ModuleAndIndex = parseAssemblyFileWithIndex(Filename: InputFilename, Err, Context,
134 Slots: nullptr, DataLayoutCallback: SetDataLayout);
135 }
136 std::unique_ptr<Module> M = std::move(ModuleAndIndex.Mod);
137 if (!M) {
138 Err.print(ProgName: argv[0], S&: errs());
139 return 1;
140 }
141
142 M->removeDebugIntrinsicDeclarations();
143
144 std::unique_ptr<ModuleSummaryIndex> Index = std::move(ModuleAndIndex.Index);
145
146 if (!DisableVerify) {
147 std::string ErrorStr;
148 raw_string_ostream OS(ErrorStr);
149 if (verifyModule(M: *M, OS: &OS)) {
150 errs() << argv[0]
151 << ": assembly parsed, but does not verify as correct!\n";
152 errs() << OS.str();
153 return 1;
154 }
155 // TODO: Implement and call summary index verifier.
156 }
157
158 if (DumpAsm) {
159 errs() << "Here's the assembly:\n" << *M;
160 if (Index.get() && Index->begin() != Index->end())
161 Index->print(OS&: errs());
162 }
163
164 if (!DisableOutput)
165 WriteOutputFile(M: M.get(), Index: Index.get());
166
167 return 0;
168}
169