1//===-- cc1_main.cpp - Clang CC1 Compiler Frontend ------------------------===//
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 is the entry point to the clang -cc1 functionality, which implements the
10// core compiler functionality along with a number of additional tools for
11// demonstration and testing purposes.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Basic/DiagnosticFrontend.h"
16#include "clang/Basic/Stack.h"
17#include "clang/Basic/TargetOptions.h"
18#include "clang/CodeGen/ObjectFilePCHContainerWriter.h"
19#include "clang/Config/config.h"
20#include "clang/Driver/Driver.h"
21#include "clang/Driver/DriverDiagnostic.h"
22#include "clang/Frontend/CompilerInstance.h"
23#include "clang/Frontend/CompilerInvocation.h"
24#include "clang/Frontend/TextDiagnosticBuffer.h"
25#include "clang/Frontend/TextDiagnosticPrinter.h"
26#include "clang/Frontend/Utils.h"
27#include "clang/FrontendTool/Utils.h"
28#include "clang/Options/Options.h"
29#include "clang/Serialization/ObjectFilePCHContainerReader.h"
30#include "llvm/ADT/Statistic.h"
31#include "llvm/ADT/StringExtras.h"
32#include "llvm/Config/llvm-config.h"
33#include "llvm/LinkAllPasses.h"
34#include "llvm/MC/MCSubtargetInfo.h"
35#include "llvm/MC/TargetRegistry.h"
36#include "llvm/Option/Arg.h"
37#include "llvm/Option/ArgList.h"
38#include "llvm/Option/OptTable.h"
39#include "llvm/Support/BuryPointer.h"
40#include "llvm/Support/Compiler.h"
41#include "llvm/Support/ErrorHandling.h"
42#include "llvm/Support/IOSandbox.h"
43#include "llvm/Support/ManagedStatic.h"
44#include "llvm/Support/Path.h"
45#include "llvm/Support/Process.h"
46#include "llvm/Support/Signals.h"
47#include "llvm/Support/TargetSelect.h"
48#include "llvm/Support/TimeProfiler.h"
49#include "llvm/Support/Timer.h"
50#include "llvm/Support/VirtualFileSystem.h"
51#include "llvm/Support/raw_ostream.h"
52#include "llvm/Target/TargetMachine.h"
53#include "llvm/TargetParser/AArch64TargetParser.h"
54#include "llvm/TargetParser/ARMTargetParser.h"
55#include "llvm/TargetParser/RISCVISAInfo.h"
56#include <cstdio>
57
58#ifdef CLANG_HAVE_RLIMITS
59#include <sys/resource.h>
60#endif
61
62using namespace clang;
63using namespace llvm::opt;
64
65//===----------------------------------------------------------------------===//
66// Main driver
67//===----------------------------------------------------------------------===//
68
69static void LLVMErrorHandler(void *UserData, const char *Message,
70 bool GenCrashDiag) {
71 DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
72
73 Diags.Report(DiagID: diag::err_fe_error_backend) << Message;
74
75 // Run the interrupt handlers to make sure any special cleanups get done, in
76 // particular that we remove files registered with RemoveFileOnSignal.
77 llvm::sys::RunInterruptHandlers();
78
79 // We cannot recover from llvm errors. When reporting a fatal error, exit
80 // with status 70 to generate crash diagnostics. For BSD systems this is
81 // defined as an internal software error. Otherwise, exit with status 1.
82 llvm::sys::Process::Exit(RetCode: GenCrashDiag ? 70 : 1);
83}
84
85#ifdef CLANG_HAVE_RLIMITS
86/// Attempt to ensure that we have at least 8MiB of usable stack space.
87static void ensureSufficientStack() {
88 struct rlimit rlim;
89 if (getrlimit(RLIMIT_STACK, rlimits: &rlim) != 0)
90 return;
91
92 // Increase the soft stack limit to our desired level, if necessary and
93 // possible.
94 if (rlim.rlim_cur != RLIM_INFINITY &&
95 rlim.rlim_cur < rlim_t(DesiredStackSize)) {
96 // Try to allocate sufficient stack.
97 if (rlim.rlim_max == RLIM_INFINITY ||
98 rlim.rlim_max >= rlim_t(DesiredStackSize))
99 rlim.rlim_cur = DesiredStackSize;
100 else if (rlim.rlim_cur == rlim.rlim_max)
101 return;
102 else
103 rlim.rlim_cur = rlim.rlim_max;
104
105 if (setrlimit(RLIMIT_STACK, rlimits: &rlim) != 0 ||
106 rlim.rlim_cur != DesiredStackSize)
107 return;
108 }
109}
110#else
111static void ensureSufficientStack() {}
112#endif
113
114/// Print supported cpus of the given target.
115static int PrintSupportedCPUs(std::string TargetStr) {
116 llvm::Triple Triple(TargetStr);
117 std::string Error;
118 const llvm::Target *TheTarget =
119 llvm::TargetRegistry::lookupTarget(TheTriple: Triple, Error);
120 if (!TheTarget) {
121 llvm::errs() << Error;
122 return 1;
123 }
124
125 // the target machine will handle the mcpu printing
126 llvm::TargetOptions Options;
127 std::unique_ptr<llvm::TargetMachine> TheTargetMachine(
128 TheTarget->createTargetMachine(TT: Triple, CPU: "", Features: "+cpuhelp", Options,
129 RM: std::nullopt));
130 return 0;
131}
132
133static int PrintSupportedExtensions(std::string TargetStr) {
134 llvm::Triple Triple(TargetStr);
135 std::string Error;
136 const llvm::Target *TheTarget =
137 llvm::TargetRegistry::lookupTarget(TheTriple: Triple, Error);
138 if (!TheTarget) {
139 llvm::errs() << Error;
140 return 1;
141 }
142
143 llvm::TargetOptions Options;
144 std::unique_ptr<llvm::TargetMachine> TheTargetMachine(
145 TheTarget->createTargetMachine(TT: Triple, CPU: "", Features: "", Options, RM: std::nullopt));
146 const llvm::Triple &MachineTriple = TheTargetMachine->getTargetTriple();
147 const llvm::MCSubtargetInfo *MCInfo = TheTargetMachine->getMCSubtargetInfo();
148 const llvm::ArrayRef<llvm::SubtargetFeatureKV> Features =
149 MCInfo->getAllProcessorFeatures();
150
151 llvm::StringMap<llvm::StringRef> DescMap;
152 for (const llvm::SubtargetFeatureKV &feature : Features)
153 DescMap.insert(KV: {feature.Key, feature.Desc});
154
155 if (MachineTriple.isRISCV())
156 llvm::RISCVISAInfo::printSupportedExtensions(DescMap);
157 else if (MachineTriple.isAArch64())
158 llvm::AArch64::PrintSupportedExtensions();
159 else if (MachineTriple.isARM())
160 llvm::ARM::PrintSupportedExtensions(DescMap);
161 else {
162 // The option was already checked in Driver::HandleImmediateArgs,
163 // so we do not expect to get here if we are not a supported architecture.
164 assert(0 && "Unhandled triple for --print-supported-extensions option.");
165 return 1;
166 }
167
168 return 0;
169}
170
171static int PrintEnabledExtensions(const TargetOptions& TargetOpts) {
172 llvm::Triple Triple(TargetOpts.Triple);
173 std::string Error;
174 const llvm::Target *TheTarget =
175 llvm::TargetRegistry::lookupTarget(TheTriple: Triple, Error);
176 if (!TheTarget) {
177 llvm::errs() << Error;
178 return 1;
179 }
180
181 // Create a target machine using the input features, the triple information
182 // and a dummy instance of llvm::TargetOptions. Note that this is _not_ the
183 // same as the `clang::TargetOptions` instance we have access to here.
184 llvm::TargetOptions BackendOptions;
185 std::string FeaturesStr = llvm::join(R: TargetOpts.FeaturesAsWritten, Separator: ",");
186 std::unique_ptr<llvm::TargetMachine> TheTargetMachine(
187 TheTarget->createTargetMachine(TT: Triple, CPU: TargetOpts.CPU, Features: FeaturesStr,
188 Options: BackendOptions, RM: std::nullopt));
189 const llvm::Triple &MachineTriple = TheTargetMachine->getTargetTriple();
190 const llvm::MCSubtargetInfo *MCInfo = TheTargetMachine->getMCSubtargetInfo();
191
192 // Extract the feature names that are enabled for the given target.
193 // We do that by capturing the key from the set of SubtargetFeatureKV entries
194 // provided by MCSubtargetInfo, which match the '-target-feature' values.
195 const std::vector<llvm::SubtargetFeatureKV> Features =
196 MCInfo->getEnabledProcessorFeatures();
197 std::set<llvm::StringRef> EnabledFeatureNames;
198 for (const llvm::SubtargetFeatureKV &feature : Features)
199 EnabledFeatureNames.insert(x: feature.Key);
200
201 if (MachineTriple.isAArch64())
202 llvm::AArch64::printEnabledExtensions(EnabledFeatureNames);
203 else if (MachineTriple.isRISCV()) {
204 llvm::StringMap<llvm::StringRef> DescMap;
205 for (const llvm::SubtargetFeatureKV &feature : Features)
206 DescMap.insert(KV: {feature.Key, feature.Desc});
207 llvm::RISCVISAInfo::printEnabledExtensions(IsRV64: MachineTriple.isArch64Bit(),
208 EnabledFeatureNames, DescMap);
209 } else {
210 // The option was already checked in Driver::HandleImmediateArgs,
211 // so we do not expect to get here if we are not a supported architecture.
212 assert(0 && "Unhandled triple for --print-enabled-extensions option.");
213 return 1;
214 }
215
216 return 0;
217}
218
219int cc1_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
220 ensureSufficientStack();
221
222 IntrusiveRefCntPtr<DiagnosticIDs> DiagID = DiagnosticIDs::create();
223
224 // Register the support for object-file-wrapped Clang modules.
225 auto PCHOps = std::make_shared<PCHContainerOperations>();
226 PCHOps->registerWriter(Writer: std::make_unique<ObjectFilePCHContainerWriter>());
227 PCHOps->registerReader(Reader: std::make_unique<ObjectFilePCHContainerReader>());
228
229 // Initialize targets first, so that --version shows registered targets.
230 llvm::InitializeAllTargets();
231 llvm::InitializeAllTargetMCs();
232 llvm::InitializeAllAsmPrinters();
233 llvm::InitializeAllAsmParsers();
234
235 // Buffer diagnostics from argument parsing so that we can output them using a
236 // well formed diagnostic object.
237 DiagnosticOptions DiagOpts;
238 TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer;
239 DiagnosticsEngine Diags(DiagID, DiagOpts, DiagsBuffer);
240
241 // Setup round-trip remarks for the DiagnosticsEngine used in CreateFromArgs.
242 if (find(Range&: Argv, Val: StringRef("-Rround-trip-cc1-args")) != Argv.end())
243 Diags.setSeverity(Diag: diag::remark_cc1_round_trip_generated,
244 Map: diag::Severity::Remark, Loc: {});
245
246 auto Invocation = std::make_shared<CompilerInvocation>();
247 bool Success =
248 CompilerInvocation::CreateFromArgs(Res&: *Invocation, CommandLineArgs: Argv, Diags, Argv0);
249
250 auto Clang = std::make_unique<CompilerInstance>(args: std::move(Invocation),
251 args: std::move(PCHOps));
252
253 if (!Clang->getFrontendOpts().TimeTracePath.empty()) {
254 llvm::timeTraceProfilerInitialize(
255 TimeTraceGranularity: Clang->getFrontendOpts().TimeTraceGranularity, ProcName: Argv0,
256 TimeTraceVerbose: Clang->getFrontendOpts().TimeTraceVerbose);
257 }
258 // --print-supported-cpus takes priority over the actual compilation.
259 if (Clang->getFrontendOpts().PrintSupportedCPUs)
260 return PrintSupportedCPUs(TargetStr: Clang->getTargetOpts().Triple);
261
262 // --print-supported-extensions takes priority over the actual compilation.
263 if (Clang->getFrontendOpts().PrintSupportedExtensions)
264 return PrintSupportedExtensions(TargetStr: Clang->getTargetOpts().Triple);
265
266 // --print-enabled-extensions takes priority over the actual compilation.
267 if (Clang->getFrontendOpts().PrintEnabledExtensions)
268 return PrintEnabledExtensions(TargetOpts: Clang->getTargetOpts());
269
270 // Infer the builtin include path if unspecified.
271 if (Clang->getHeaderSearchOpts().UseBuiltinIncludes &&
272 Clang->getHeaderSearchOpts().ResourceDir.empty())
273 Clang->getHeaderSearchOpts().ResourceDir =
274 GetResourcesPath(Argv0, MainAddr);
275
276 /// Create the actual file system.
277 auto VFS = [] {
278 auto BypassSandbox = llvm::sys::sandbox::scopedDisable();
279 return llvm::vfs::getRealFileSystem();
280 }();
281 Clang->createVirtualFileSystem(BaseFS: std::move(VFS), DC: DiagsBuffer);
282
283 // Create the actual diagnostics engine.
284 Clang->createDiagnostics();
285
286 // Set an error handler, so that any LLVM backend diagnostics go through our
287 // error handler.
288 llvm::install_fatal_error_handler(handler: LLVMErrorHandler,
289 user_data: static_cast<void*>(&Clang->getDiagnostics()));
290
291 DiagsBuffer->FlushDiagnostics(Diags&: Clang->getDiagnostics());
292 if (!Success) {
293 Clang->getDiagnosticClient().finish();
294 return 1;
295 }
296
297 // Execute the frontend actions.
298 {
299 llvm::TimeTraceScope TimeScope("ExecuteCompiler");
300 bool TimePasses = Clang->getCodeGenOpts().TimePasses;
301 if (TimePasses)
302 Clang->createFrontendTimer();
303 llvm::TimeRegion Timer(TimePasses ? &Clang->getFrontendTimer() : nullptr);
304 Success = ExecuteCompilerInvocation(Clang: Clang.get());
305 }
306
307 // If any timers were active but haven't been destroyed yet, print their
308 // results now. This happens in -disable-free mode.
309 {
310 // This isn't a formal input or output of the compiler.
311 auto BypassSandbox = llvm::sys::sandbox::scopedDisable();
312 std::unique_ptr<raw_ostream> IOFile = llvm::CreateInfoOutputFile();
313 if (Clang->getCodeGenOpts().TimePassesJson) {
314 *IOFile << "{\n";
315 llvm::TimerGroup::printAllJSONValues(OS&: *IOFile, delim: "");
316 *IOFile << "\n}\n";
317 } else if (!Clang->getCodeGenOpts().TimePassesStatsFile) {
318 llvm::TimerGroup::printAll(OS&: *IOFile);
319 }
320 llvm::TimerGroup::clearAll();
321 }
322
323 if (llvm::timeTraceProfilerEnabled()) {
324 if (auto profilerOutput = Clang->createOutputFile(
325 OutputPath: Clang->getFrontendOpts().TimeTracePath, /*Binary=*/false,
326 /*RemoveFileOnSignal=*/false,
327 /*useTemporary=*/UseTemporary: false)) {
328 llvm::timeTraceProfilerWrite(OS&: *profilerOutput);
329 profilerOutput.reset();
330 llvm::timeTraceProfilerCleanup();
331 Clang->clearOutputFiles(EraseFiles: false);
332 }
333 }
334
335 // Our error handler depends on the Diagnostics object, which we're
336 // potentially about to delete. Uninstall the handler now so that any
337 // later errors use the default handling behavior instead.
338 llvm::remove_fatal_error_handler();
339
340 // When running with -disable-free, don't do any destruction or shutdown.
341 if (Clang->getFrontendOpts().DisableFree) {
342 llvm::BuryPointer(Ptr: std::move(Clang));
343 return !Success;
344 }
345
346 return !Success;
347}
348