1//===--- CompileCommands.cpp ----------------------------------------------===//
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#include "CompileCommands.h"
10#include "Config.h"
11#include "support/Logger.h"
12#include "support/Trace.h"
13#include "clang/Driver/Driver.h"
14#include "clang/Driver/Options.h"
15#include "clang/Frontend/CompilerInvocation.h"
16#include "clang/Tooling/CompilationDatabase.h"
17#include "clang/Tooling/Tooling.h"
18#include "llvm/ADT/ArrayRef.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/ADT/SmallVector.h"
21#include "llvm/ADT/StringRef.h"
22#include "llvm/Option/ArgList.h"
23#include "llvm/Option/Option.h"
24#include "llvm/Support/Allocator.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/FileSystem.h"
27#include "llvm/Support/FileUtilities.h"
28#include "llvm/Support/MemoryBuffer.h"
29#include "llvm/Support/Path.h"
30#include "llvm/Support/Program.h"
31#include <iterator>
32#include <optional>
33#include <string>
34#include <vector>
35
36namespace clang {
37namespace clangd {
38namespace {
39
40// Query apple's `xcrun` launcher, which is the source of truth for "how should"
41// clang be invoked on this system.
42std::optional<std::string> queryXcrun(llvm::ArrayRef<llvm::StringRef> Argv) {
43 auto Xcrun = llvm::sys::findProgramByName(Name: "xcrun");
44 if (!Xcrun) {
45 log(Fmt: "Couldn't find xcrun. Hopefully you have a non-apple toolchain...");
46 return std::nullopt;
47 }
48 llvm::SmallString<64> OutFile;
49 llvm::sys::fs::createTemporaryFile(Prefix: "clangd-xcrun", Suffix: "", ResultPath&: OutFile);
50 llvm::FileRemover OutRemover(OutFile);
51 std::optional<llvm::StringRef> Redirects[3] = {
52 /*stdin=*/{""}, /*stdout=*/{OutFile.str()}, /*stderr=*/{""}};
53 vlog(Fmt: "Invoking {0} to find clang installation", Vals&: *Xcrun);
54 int Ret = llvm::sys::ExecuteAndWait(Program: *Xcrun, Args: Argv,
55 /*Env=*/std::nullopt, Redirects,
56 /*SecondsToWait=*/10);
57 if (Ret != 0) {
58 log(Fmt: "xcrun exists but failed with code {0}. "
59 "If you have a non-apple toolchain, this is OK. "
60 "Otherwise, try xcode-select --install.",
61 Vals&: Ret);
62 return std::nullopt;
63 }
64
65 auto Buf = llvm::MemoryBuffer::getFile(Filename: OutFile);
66 if (!Buf) {
67 log(Fmt: "Can't read xcrun output: {0}", Vals: Buf.getError().message());
68 return std::nullopt;
69 }
70 StringRef Path = Buf->get()->getBuffer().trim();
71 if (Path.empty()) {
72 log(Fmt: "xcrun produced no output");
73 return std::nullopt;
74 }
75 return Path.str();
76}
77
78// Resolve symlinks if possible.
79std::string resolve(std::string Path) {
80 llvm::SmallString<128> Resolved;
81 if (llvm::sys::fs::real_path(path: Path, output&: Resolved)) {
82 log(Fmt: "Failed to resolve possible symlink {0}", Vals&: Path);
83 return Path;
84 }
85 return std::string(Resolved);
86}
87
88// Get a plausible full `clang` path.
89// This is used in the fallback compile command, or when the CDB returns a
90// generic driver with no path.
91std::string detectClangPath() {
92 // The driver and/or cc1 sometimes depend on the binary name to compute
93 // useful things like the standard library location.
94 // We need to emulate what clang on this system is likely to see.
95 // cc1 in particular looks at the "real path" of the running process, and
96 // so if /usr/bin/clang is a symlink, it sees the resolved path.
97 // clangd doesn't have that luxury, so we resolve symlinks ourselves.
98
99 // On Mac, `which clang` is /usr/bin/clang. It runs `xcrun clang`, which knows
100 // where the real clang is kept. We need to do the same thing,
101 // because cc1 (not the driver!) will find libc++ relative to argv[0].
102#ifdef __APPLE__
103 if (auto MacClang = queryXcrun({"xcrun", "--find", "clang"}))
104 return resolve(std::move(*MacClang));
105#endif
106 // On other platforms, just look for compilers on the PATH.
107 for (const char *Name : {"clang", "gcc", "cc"})
108 if (auto PathCC = llvm::sys::findProgramByName(Name))
109 return resolve(Path: std::move(*PathCC));
110 // Fallback: a nonexistent 'clang' binary next to clangd.
111 static int StaticForMainAddr;
112 std::string ClangdExecutable =
113 llvm::sys::fs::getMainExecutable(argv0: "clangd", MainExecAddr: (void *)&StaticForMainAddr);
114 SmallString<128> ClangPath;
115 ClangPath = llvm::sys::path::parent_path(path: ClangdExecutable);
116 llvm::sys::path::append(path&: ClangPath, a: "clang");
117 return std::string(ClangPath);
118}
119
120// On mac, /usr/bin/clang sets SDKROOT and then invokes the real clang.
121// The effect of this is to set -isysroot correctly. We do the same.
122std::optional<std::string> detectSysroot() {
123#ifndef __APPLE__
124 return std::nullopt;
125#endif
126
127 // SDKROOT overridden in environment, respect it. Driver will set isysroot.
128 if (::getenv(name: "SDKROOT"))
129 return std::nullopt;
130 return queryXcrun(Argv: {"xcrun", "--show-sdk-path"});
131}
132
133std::string detectStandardResourceDir() {
134 static int StaticForMainAddr; // Just an address in this process.
135 return CompilerInvocation::GetResourcesPath(Argv0: "clangd",
136 MainAddr: (void *)&StaticForMainAddr);
137}
138
139// The path passed to argv[0] is important:
140// - its parent directory is Driver::Dir, used for library discovery
141// - its basename affects CLI parsing (clang-cl) and other settings
142// Where possible it should be an absolute path with sensible directory, but
143// with the original basename.
144static std::string resolveDriver(llvm::StringRef Driver, bool FollowSymlink,
145 std::optional<std::string> ClangPath) {
146 auto SiblingOf = [&](llvm::StringRef AbsPath) {
147 llvm::SmallString<128> Result = llvm::sys::path::parent_path(path: AbsPath);
148 llvm::sys::path::append(path&: Result, a: llvm::sys::path::filename(path: Driver));
149 return Result.str().str();
150 };
151
152 // First, eliminate relative paths.
153 std::string Storage;
154 if (!llvm::sys::path::is_absolute(path: Driver)) {
155 // If it's working-dir relative like bin/clang, we can't resolve it.
156 // FIXME: we could if we had the working directory here.
157 // Let's hope it's not a symlink.
158 if (llvm::any_of(Range&: Driver,
159 P: [](char C) { return llvm::sys::path::is_separator(value: C); }))
160 return Driver.str();
161 // If the driver is a generic like "g++" with no path, add clang dir.
162 if (ClangPath &&
163 (Driver == "clang" || Driver == "clang++" || Driver == "gcc" ||
164 Driver == "g++" || Driver == "cc" || Driver == "c++")) {
165 return SiblingOf(*ClangPath);
166 }
167 // Otherwise try to look it up on PATH. This won't change basename.
168 auto Absolute = llvm::sys::findProgramByName(Name: Driver);
169 if (Absolute && llvm::sys::path::is_absolute(path: *Absolute))
170 Driver = Storage = std::move(*Absolute);
171 else if (ClangPath) // If we don't find it, use clang dir again.
172 return SiblingOf(*ClangPath);
173 else // Nothing to do: can't find the command and no detected dir.
174 return Driver.str();
175 }
176
177 // Now we have an absolute path, but it may be a symlink.
178 assert(llvm::sys::path::is_absolute(Driver));
179 if (FollowSymlink) {
180 llvm::SmallString<256> Resolved;
181 if (!llvm::sys::fs::real_path(path: Driver, output&: Resolved))
182 return SiblingOf(Resolved);
183 }
184 return Driver.str();
185}
186
187} // namespace
188
189CommandMangler CommandMangler::detect() {
190 CommandMangler Result;
191 Result.ClangPath = detectClangPath();
192 Result.ResourceDir = detectStandardResourceDir();
193 Result.Sysroot = detectSysroot();
194 return Result;
195}
196
197CommandMangler CommandMangler::forTests() { return CommandMangler(); }
198
199void CommandMangler::operator()(tooling::CompileCommand &Command,
200 llvm::StringRef File) const {
201 std::vector<std::string> &Cmd = Command.CommandLine;
202 trace::Span S("AdjustCompileFlags");
203 // Most of the modifications below assumes the Cmd starts with a driver name.
204 // We might consider injecting a generic driver name like "cc" or "c++", but
205 // a Cmd missing the driver is probably rare enough in practice and erroneous.
206 if (Cmd.empty())
207 return;
208
209 auto &OptTable = clang::driver::getDriverOptTable();
210 // OriginalArgs needs to outlive ArgList.
211 llvm::SmallVector<const char *, 16> OriginalArgs;
212 OriginalArgs.reserve(N: Cmd.size());
213 for (const auto &S : Cmd)
214 OriginalArgs.push_back(Elt: S.c_str());
215 bool IsCLMode = driver::IsClangCL(DriverMode: driver::getDriverMode(
216 ProgName: OriginalArgs[0], Args: llvm::ArrayRef(OriginalArgs).slice(N: 1)));
217 // ParseArgs propagates missing arg/opt counts on error, but preserves
218 // everything it could parse in ArgList. So we just ignore those counts.
219 unsigned IgnoredCount;
220 // Drop the executable name, as ParseArgs doesn't expect it. This means
221 // indices are actually of by one between ArgList and OriginalArgs.
222 llvm::opt::InputArgList ArgList;
223 ArgList = OptTable.ParseArgs(
224 Args: llvm::ArrayRef(OriginalArgs).drop_front(), MissingArgIndex&: IgnoredCount, MissingArgCount&: IgnoredCount,
225 VisibilityMask: llvm::opt::Visibility(IsCLMode ? driver::options::CLOption
226 : driver::options::ClangOption));
227
228 llvm::SmallVector<unsigned, 1> IndicesToDrop;
229 // Having multiple architecture options (e.g. when building fat binaries)
230 // results in multiple compiler jobs, which clangd cannot handle. In such
231 // cases strip all the `-arch` options and fallback to default architecture.
232 // As there are no signals to figure out which one user actually wants. They
233 // can explicitly specify one through `CompileFlags.Add` if need be.
234 unsigned ArchOptCount = 0;
235 for (auto *Input : ArgList.filtered(driver::options::OPT_arch)) {
236 ++ArchOptCount;
237 for (auto I = 0U; I <= Input->getNumValues(); ++I)
238 IndicesToDrop.push_back(Input->getIndex() + I);
239 }
240 // If there is a single `-arch` option, keep it.
241 if (ArchOptCount < 2)
242 IndicesToDrop.clear();
243
244 // In some cases people may try to reuse the command from another file, e.g.
245 // { File: "foo.h", CommandLine: "clang foo.cpp" }.
246 // We assume the intent is to parse foo.h the same way as foo.cpp, or as if
247 // it were being included from foo.cpp.
248 //
249 // We're going to rewrite the command to refer to foo.h, and this may change
250 // its semantics (e.g. by parsing the file as C). If we do this, we should
251 // use transferCompileCommand to adjust the argv.
252 // In practice only the extension of the file matters, so do this only when
253 // it differs.
254 llvm::StringRef FileExtension = llvm::sys::path::extension(path: File);
255 std::optional<std::string> TransferFrom;
256 auto SawInput = [&](llvm::StringRef Input) {
257 if (llvm::sys::path::extension(path: Input) != FileExtension)
258 TransferFrom.emplace(args&: Input);
259 };
260
261 // Strip all the inputs and `--`. We'll put the input for the requested file
262 // explicitly at the end of the flags. This ensures modifications done in the
263 // following steps apply in more cases (like setting -x, which only affects
264 // inputs that come after it).
265 for (auto *Input : ArgList.filtered(driver::options::OPT_INPUT)) {
266 SawInput(Input->getValue(0));
267 IndicesToDrop.push_back(Input->getIndex());
268 }
269 // Anything after `--` is also treated as input, drop them as well.
270 if (auto *DashDash =
271 ArgList.getLastArgNoClaim(driver::options::OPT__DASH_DASH)) {
272 auto DashDashIndex = DashDash->getIndex() + 1; // +1 accounts for Cmd[0]
273 for (unsigned I = DashDashIndex; I < Cmd.size(); ++I)
274 SawInput(Cmd[I]);
275 Cmd.resize(DashDashIndex);
276 }
277 llvm::sort(C&: IndicesToDrop);
278 for (unsigned Idx : llvm::reverse(C&: IndicesToDrop))
279 // +1 to account for the executable name in Cmd[0] that
280 // doesn't exist in ArgList.
281 Cmd.erase(position: Cmd.begin() + Idx + 1);
282 // All the inputs are stripped, append the name for the requested file. Rest
283 // of the modifications should respect `--`.
284 Cmd.push_back(x: "--");
285 Cmd.push_back(x: File.str());
286
287 if (TransferFrom) {
288 tooling::CompileCommand TransferCmd;
289 TransferCmd.Filename = std::move(*TransferFrom);
290 TransferCmd.CommandLine = std::move(Cmd);
291 TransferCmd = transferCompileCommand(std::move(TransferCmd), Filename: File);
292 Cmd = std::move(TransferCmd.CommandLine);
293 assert(Cmd.size() >= 2 && Cmd.back() == File &&
294 Cmd[Cmd.size() - 2] == "--" &&
295 "TransferCommand should produce a command ending in -- filename");
296 }
297
298 for (auto &Edit : Config::current().CompileFlags.Edits)
299 Edit(Cmd);
300
301 // The system include extractor needs to run:
302 // - AFTER transferCompileCommand(), because the -x flag it adds may be
303 // necessary for the system include extractor to identify the file type
304 // - AFTER applying CompileFlags.Edits, because the name of the compiler
305 // that needs to be invoked may come from the CompileFlags->Compiler key
306 // - BEFORE addTargetAndModeForProgramName(), because gcc doesn't support
307 // the target flag that might be added.
308 // - BEFORE resolveDriver() because that can mess up the driver path,
309 // e.g. changing gcc to /path/to/clang/bin/gcc
310 if (SystemIncludeExtractor) {
311 SystemIncludeExtractor(Command, File);
312 }
313
314 tooling::addTargetAndModeForProgramName(CommandLine&: Cmd, InvokedAs: Cmd.front());
315
316 // Check whether the flag exists in the command.
317 auto HasExact = [&](llvm::StringRef Flag) {
318 return llvm::is_contained(Range&: Cmd, Element: Flag);
319 };
320
321 // Check whether the flag appears in the command as a prefix.
322 auto HasPrefix = [&](llvm::StringRef Flag) {
323 return llvm::any_of(
324 Range&: Cmd, P: [&](llvm::StringRef Arg) { return Arg.starts_with(Prefix: Flag); });
325 };
326
327 llvm::erase_if(C&: Cmd, P: [](llvm::StringRef Elem) {
328 return Elem.starts_with(Prefix: "--save-temps") || Elem.starts_with(Prefix: "-save-temps");
329 });
330
331 std::vector<std::string> ToAppend;
332 if (ResourceDir && !HasExact("-resource-dir") && !HasPrefix("-resource-dir="))
333 ToAppend.push_back(x: ("-resource-dir=" + *ResourceDir));
334
335 // Don't set `-isysroot` if it is already set or if `--sysroot` is set.
336 // `--sysroot` is a superset of the `-isysroot` argument.
337 if (Sysroot && !HasPrefix("-isysroot") && !HasExact("--sysroot") &&
338 !HasPrefix("--sysroot=")) {
339 ToAppend.push_back(x: "-isysroot");
340 ToAppend.push_back(x: *Sysroot);
341 }
342
343 if (!ToAppend.empty()) {
344 Cmd.insert(position: llvm::find(Range&: Cmd, Val: "--"), first: std::make_move_iterator(i: ToAppend.begin()),
345 last: std::make_move_iterator(i: ToAppend.end()));
346 }
347
348 if (!Cmd.empty()) {
349 bool FollowSymlink = !HasExact("-no-canonical-prefixes");
350 Cmd.front() =
351 (FollowSymlink ? ResolvedDrivers : ResolvedDriversNoFollow)
352 .get(Key&: Cmd.front(), Compute: [&, this] {
353 return resolveDriver(Driver: Cmd.front(), FollowSymlink, ClangPath);
354 });
355 }
356}
357
358// ArgStripper implementation
359namespace {
360
361// Determine total number of args consumed by this option.
362// Return answers for {Exact, Prefix} match. 0 means not allowed.
363std::pair<unsigned, unsigned> getArgCount(const llvm::opt::Option &Opt) {
364 constexpr static unsigned Rest = 10000; // Should be all the rest!
365 // Reference is llvm::opt::Option::acceptInternal()
366 using llvm::opt::Option;
367 switch (Opt.getKind()) {
368 case Option::FlagClass:
369 return {1, 0};
370 case Option::JoinedClass:
371 case Option::CommaJoinedClass:
372 return {1, 1};
373 case Option::GroupClass:
374 case Option::InputClass:
375 case Option::UnknownClass:
376 case Option::ValuesClass:
377 return {1, 0};
378 case Option::JoinedAndSeparateClass:
379 return {2, 2};
380 case Option::SeparateClass:
381 return {2, 0};
382 case Option::MultiArgClass:
383 return {1 + Opt.getNumArgs(), 0};
384 case Option::JoinedOrSeparateClass:
385 return {2, 1};
386 case Option::RemainingArgsClass:
387 return {Rest, 0};
388 case Option::RemainingArgsJoinedClass:
389 return {Rest, Rest};
390 }
391 llvm_unreachable("Unhandled option kind");
392}
393
394// Flag-parsing mode, which affects which flags are available.
395enum DriverMode : unsigned char {
396 DM_None = 0,
397 DM_GCC = 1, // Default mode e.g. when invoked as 'clang'
398 DM_CL = 2, // MS CL.exe compatible mode e.g. when invoked as 'clang-cl'
399 DM_CC1 = 4, // When invoked as 'clang -cc1' or after '-Xclang'
400 DM_All = 7
401};
402
403// Examine args list to determine if we're in GCC, CL-compatible, or cc1 mode.
404DriverMode getDriverMode(const std::vector<std::string> &Args) {
405 DriverMode Mode = DM_GCC;
406 llvm::StringRef Argv0 = Args.front();
407 Argv0.consume_back_insensitive(Suffix: ".exe");
408 if (Argv0.ends_with_insensitive(Suffix: "cl"))
409 Mode = DM_CL;
410 for (const llvm::StringRef Arg : Args) {
411 if (Arg == "--driver-mode=cl") {
412 Mode = DM_CL;
413 break;
414 }
415 if (Arg == "-cc1") {
416 Mode = DM_CC1;
417 break;
418 }
419 }
420 return Mode;
421}
422
423// Returns the set of DriverModes where an option may be used.
424unsigned char getModes(const llvm::opt::Option &Opt) {
425 unsigned char Result = DM_None;
426 if (Opt.hasVisibilityFlag(Val: driver::options::ClangOption))
427 Result |= DM_GCC;
428 if (Opt.hasVisibilityFlag(Val: driver::options::CC1Option))
429 Result |= DM_CC1;
430 if (Opt.hasVisibilityFlag(Val: driver::options::CLOption))
431 Result |= DM_CL;
432 return Result;
433}
434
435} // namespace
436
437llvm::ArrayRef<ArgStripper::Rule> ArgStripper::rulesFor(llvm::StringRef Arg) {
438 // All the hard work is done once in a static initializer.
439 // We compute a table containing strings to look for and #args to skip.
440 // e.g. "-x" => {-x 2 args, -x* 1 arg, --language 2 args, --language=* 1 arg}
441 using TableTy =
442 llvm::StringMap<llvm::SmallVector<Rule, 4>, llvm::BumpPtrAllocator>;
443 static TableTy *Table = [] {
444 auto &DriverTable = driver::getDriverOptTable();
445 using DriverID = clang::driver::options::ID;
446
447 // Collect sets of aliases, so we can treat -foo and -foo= as synonyms.
448 // Conceptually a double-linked list: PrevAlias[I] -> I -> NextAlias[I].
449 // If PrevAlias[I] is INVALID, then I is canonical.
450 DriverID PrevAlias[DriverID::LastOption] = {DriverID::OPT_INVALID};
451 DriverID NextAlias[DriverID::LastOption] = {DriverID::OPT_INVALID};
452 auto AddAlias = [&](DriverID Self, DriverID T) {
453 if (NextAlias[T]) {
454 PrevAlias[NextAlias[T]] = Self;
455 NextAlias[Self] = NextAlias[T];
456 }
457 PrevAlias[Self] = T;
458 NextAlias[T] = Self;
459 };
460
461 struct {
462 DriverID ID;
463 DriverID AliasID;
464 const void *AliasArgs;
465 } AliasTable[] = {
466#define OPTION(PREFIX, PREFIXED_NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, \
467 FLAGS, VISIBILITY, PARAM, HELPTEXT, HELPTEXTSFORVARIANTS, \
468 METAVAR, VALUES) \
469 {DriverID::OPT_##ID, DriverID::OPT_##ALIAS, ALIASARGS},
470#include "clang/Driver/Options.inc"
471#undef OPTION
472 };
473 for (auto &E : AliasTable)
474 if (E.AliasID != DriverID::OPT_INVALID && E.AliasArgs == nullptr)
475 AddAlias(E.ID, E.AliasID);
476
477 auto Result = std::make_unique<TableTy>();
478 // Iterate over distinct options (represented by the canonical alias).
479 // Every spelling of this option will get the same set of rules.
480 for (unsigned ID = 1 /*Skip INVALID */; ID < DriverID::LastOption; ++ID) {
481 if (PrevAlias[ID] || ID == DriverID::OPT_Xclang)
482 continue; // Not canonical, or specially handled.
483 llvm::SmallVector<Rule> Rules;
484 // Iterate over each alias, to add rules for parsing it.
485 for (unsigned A = ID; A != DriverID::OPT_INVALID; A = NextAlias[A]) {
486 llvm::SmallVector<llvm::StringRef, 4> Prefixes;
487 DriverTable.appendOptionPrefixes(id: A, Prefixes&: Prefixes);
488 if (Prefixes.empty()) // option groups.
489 continue;
490 auto Opt = DriverTable.getOption(Opt: A);
491 // Exclude - and -foo pseudo-options.
492 if (Opt.getName().empty())
493 continue;
494 auto Modes = getModes(Opt);
495 std::pair<unsigned, unsigned> ArgCount = getArgCount(Opt);
496 // Iterate over each spelling of the alias, e.g. -foo vs --foo.
497 for (StringRef Prefix : Prefixes) {
498 llvm::SmallString<64> Buf(Prefix);
499 Buf.append(Opt.getName());
500 llvm::StringRef Spelling = Result->try_emplace(Buf).first->getKey();
501 Rules.emplace_back();
502 Rule &R = Rules.back();
503 R.Text = Spelling;
504 R.Modes = Modes;
505 R.ExactArgs = ArgCount.first;
506 R.PrefixArgs = ArgCount.second;
507 // Concrete priority is the index into the option table.
508 // Effectively, earlier entries take priority over later ones.
509 assert(ID < std::numeric_limits<decltype(R.Priority)>::max() &&
510 "Rules::Priority overflowed by options table");
511 R.Priority = ID;
512 }
513 }
514 // Register the set of rules under each possible name.
515 for (const auto &R : Rules)
516 Result->find(R.Text)->second.append(Rules.begin(), Rules.end());
517 }
518#ifndef NDEBUG
519 // Dump the table and various measures of its size.
520 unsigned RuleCount = 0;
521 dlog("ArgStripper Option spelling table");
522 for (const auto &Entry : *Result) {
523 dlog("{0}", Entry.first());
524 RuleCount += Entry.second.size();
525 for (const auto &R : Entry.second)
526 dlog(" {0} #={1} *={2} Mode={3}", R.Text, R.ExactArgs, R.PrefixArgs,
527 int(R.Modes));
528 }
529 dlog("Table spellings={0} rules={1} string-bytes={2}", Result->size(),
530 RuleCount, Result->getAllocator().getBytesAllocated());
531#endif
532 // The static table will never be destroyed.
533 return Result.release();
534 }();
535
536 auto It = Table->find(Arg);
537 return (It == Table->end()) ? llvm::ArrayRef<Rule>() : It->second;
538}
539
540void ArgStripper::strip(llvm::StringRef Arg) {
541 auto OptionRules = rulesFor(Arg);
542 if (OptionRules.empty()) {
543 // Not a recognized flag. Strip it literally.
544 Storage.emplace_back(Arg);
545 Rules.emplace_back();
546 Rules.back().Text = Storage.back();
547 Rules.back().ExactArgs = 1;
548 if (Rules.back().Text.consume_back(Suffix: "*"))
549 Rules.back().PrefixArgs = 1;
550 Rules.back().Modes = DM_All;
551 Rules.back().Priority = -1; // Max unsigned = lowest priority.
552 } else {
553 Rules.append(OptionRules.begin(), OptionRules.end());
554 }
555}
556
557const ArgStripper::Rule *ArgStripper::matchingRule(llvm::StringRef Arg,
558 unsigned Mode,
559 unsigned &ArgCount) const {
560 const ArgStripper::Rule *BestRule = nullptr;
561 for (const Rule &R : Rules) {
562 // Rule can fail to match if...
563 if (!(R.Modes & Mode))
564 continue; // not applicable to current driver mode
565 if (BestRule && BestRule->Priority < R.Priority)
566 continue; // lower-priority than best candidate.
567 if (!Arg.starts_with(Prefix: R.Text))
568 continue; // current arg doesn't match the prefix string
569 bool PrefixMatch = Arg.size() > R.Text.size();
570 // Can rule apply as an exact/prefix match?
571 if (unsigned Count = PrefixMatch ? R.PrefixArgs : R.ExactArgs) {
572 BestRule = &R;
573 ArgCount = Count;
574 }
575 // Continue in case we find a higher-priority rule.
576 }
577 return BestRule;
578}
579
580void ArgStripper::process(std::vector<std::string> &Args) const {
581 if (Args.empty())
582 return;
583
584 // We're parsing the args list in some mode (e.g. gcc-compatible) but may
585 // temporarily switch to another mode with the -Xclang flag.
586 DriverMode MainMode = getDriverMode(Args);
587 DriverMode CurrentMode = MainMode;
588
589 // Read and write heads for in-place deletion.
590 unsigned Read = 0, Write = 0;
591 bool WasXclang = false;
592 while (Read < Args.size()) {
593 unsigned ArgCount = 0;
594 if (matchingRule(Arg: Args[Read], Mode: CurrentMode, ArgCount)) {
595 // Delete it and its args.
596 if (WasXclang) {
597 assert(Write > 0);
598 --Write; // Drop previous -Xclang arg
599 CurrentMode = MainMode;
600 WasXclang = false;
601 }
602 // Advance to last arg. An arg may be foo or -Xclang foo.
603 for (unsigned I = 1; Read < Args.size() && I < ArgCount; ++I) {
604 ++Read;
605 if (Read < Args.size() && Args[Read] == "-Xclang")
606 ++Read;
607 }
608 } else {
609 // No match, just copy the arg through.
610 WasXclang = Args[Read] == "-Xclang";
611 CurrentMode = WasXclang ? DM_CC1 : MainMode;
612 if (Write != Read)
613 Args[Write] = std::move(Args[Read]);
614 ++Write;
615 }
616 ++Read;
617 }
618 Args.resize(Write);
619}
620
621std::string printArgv(llvm::ArrayRef<llvm::StringRef> Args) {
622 std::string Buf;
623 llvm::raw_string_ostream OS(Buf);
624 bool Sep = false;
625 for (llvm::StringRef Arg : Args) {
626 if (Sep)
627 OS << ' ';
628 Sep = true;
629 if (llvm::all_of(Arg, llvm::isPrint) &&
630 Arg.find_first_of(Chars: " \t\n\"\\") == llvm::StringRef::npos) {
631 OS << Arg;
632 continue;
633 }
634 OS << '"';
635 OS.write_escaped(Str: Arg, /*UseHexEscapes=*/true);
636 OS << '"';
637 }
638 return std::move(OS.str());
639}
640
641std::string printArgv(llvm::ArrayRef<std::string> Args) {
642 std::vector<llvm::StringRef> Refs(Args.size());
643 llvm::copy(Args, Refs.begin());
644 return printArgv(Refs);
645}
646
647} // namespace clangd
648} // namespace clang
649

source code of clang-tools-extra/clangd/CompileCommands.cpp