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llvm-project/clang-tools-extra/clangd/CompileCommands.cpp

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//===--- CompileCommands.cpp ----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "CompileCommands.h"
#include "Config.h"
#include "support/Logger.h"
#include "clang/Driver/Options.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Tooling/ArgumentsAdjusters.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Program.h"
#include <string>
#include <vector>
namespace clang {
namespace clangd {
namespace {
// Query apple's `xcrun` launcher, which is the source of truth for "how should"
// clang be invoked on this system.
llvm::Optional<std::string> queryXcrun(llvm::ArrayRef<llvm::StringRef> Argv) {
auto Xcrun = llvm::sys::findProgramByName("xcrun");
if (!Xcrun) {
log("Couldn't find xcrun. Hopefully you have a non-apple toolchain...");
return llvm::None;
}
llvm::SmallString<64> OutFile;
llvm::sys::fs::createTemporaryFile("clangd-xcrun", "", OutFile);
llvm::FileRemover OutRemover(OutFile);
llvm::Optional<llvm::StringRef> Redirects[3] = {
/*stdin=*/{""}, /*stdout=*/{OutFile}, /*stderr=*/{""}};
vlog("Invoking {0} to find clang installation", *Xcrun);
int Ret = llvm::sys::ExecuteAndWait(*Xcrun, Argv,
/*Env=*/llvm::None, Redirects,
/*SecondsToWait=*/10);
if (Ret != 0) {
log("xcrun exists but failed with code {0}. "
"If you have a non-apple toolchain, this is OK. "
"Otherwise, try xcode-select --install.",
Ret);
return llvm::None;
}
auto Buf = llvm::MemoryBuffer::getFile(OutFile);
if (!Buf) {
log("Can't read xcrun output: {0}", Buf.getError().message());
return llvm::None;
}
StringRef Path = Buf->get()->getBuffer().trim();
if (Path.empty()) {
log("xcrun produced no output");
return llvm::None;
}
return Path.str();
}
// Resolve symlinks if possible.
std::string resolve(std::string Path) {
llvm::SmallString<128> Resolved;
if (llvm::sys::fs::real_path(Path, Resolved)) {
log("Failed to resolve possible symlink {0}", Path);
return Path;
}
return std::string(Resolved.str());
}
// Get a plausible full `clang` path.
// This is used in the fallback compile command, or when the CDB returns a
// generic driver with no path.
std::string detectClangPath() {
// The driver and/or cc1 sometimes depend on the binary name to compute
// useful things like the standard library location.
// We need to emulate what clang on this system is likely to see.
// cc1 in particular looks at the "real path" of the running process, and
// so if /usr/bin/clang is a symlink, it sees the resolved path.
// clangd doesn't have that luxury, so we resolve symlinks ourselves.
// On Mac, `which clang` is /usr/bin/clang. It runs `xcrun clang`, which knows
// where the real clang is kept. We need to do the same thing,
// because cc1 (not the driver!) will find libc++ relative to argv[0].
#ifdef __APPLE__
if (auto MacClang = queryXcrun({"xcrun", "--find", "clang"}))
return resolve(std::move(*MacClang));
#endif
// On other platforms, just look for compilers on the PATH.
for (const char *Name : {"clang", "gcc", "cc"})
if (auto PathCC = llvm::sys::findProgramByName(Name))
return resolve(std::move(*PathCC));
// Fallback: a nonexistent 'clang' binary next to clangd.
static int StaticForMainAddr;
std::string ClangdExecutable =
llvm::sys::fs::getMainExecutable("clangd", (void *)&StaticForMainAddr);
SmallString<128> ClangPath;
ClangPath = llvm::sys::path::parent_path(ClangdExecutable);
llvm::sys::path::append(ClangPath, "clang");
return std::string(ClangPath.str());
}
// On mac, /usr/bin/clang sets SDKROOT and then invokes the real clang.
// The effect of this is to set -isysroot correctly. We do the same.
const llvm::Optional<std::string> detectSysroot() {
#ifndef __APPLE__
return llvm::None;
#endif
// SDKROOT overridden in environment, respect it. Driver will set isysroot.
if (::getenv("SDKROOT"))
return llvm::None;
return queryXcrun({"xcrun", "--show-sdk-path"});
return llvm::None;
}
std::string detectStandardResourceDir() {
static int StaticForMainAddr; // Just an address in this process.
return CompilerInvocation::GetResourcesPath("clangd",
(void *)&StaticForMainAddr);
}
// The path passed to argv[0] is important:
// - its parent directory is Driver::Dir, used for library discovery
// - its basename affects CLI parsing (clang-cl) and other settings
// Where possible it should be an absolute path with sensible directory, but
// with the original basename.
static std::string resolveDriver(llvm::StringRef Driver, bool FollowSymlink,
llvm::Optional<std::string> ClangPath) {
auto SiblingOf = [&](llvm::StringRef AbsPath) {
llvm::SmallString<128> Result = llvm::sys::path::parent_path(AbsPath);
llvm::sys::path::append(Result, llvm::sys::path::filename(Driver));
return Result.str().str();
};
// First, eliminate relative paths.
std::string Storage;
if (!llvm::sys::path::is_absolute(Driver)) {
// If it's working-dir relative like bin/clang, we can't resolve it.
// FIXME: we could if we had the working directory here.
// Let's hope it's not a symlink.
if (llvm::any_of(Driver,
[](char C) { return llvm::sys::path::is_separator(C); }))
return Driver.str();
// If the driver is a generic like "g++" with no path, add clang dir.
if (ClangPath &&
(Driver == "clang" || Driver == "clang++" || Driver == "gcc" ||
Driver == "g++" || Driver == "cc" || Driver == "c++")) {
return SiblingOf(*ClangPath);
}
// Otherwise try to look it up on PATH. This won't change basename.
auto Absolute = llvm::sys::findProgramByName(Driver);
if (Absolute && llvm::sys::path::is_absolute(*Absolute))
Driver = Storage = std::move(*Absolute);
else if (ClangPath) // If we don't find it, use clang dir again.
return SiblingOf(*ClangPath);
else // Nothing to do: can't find the command and no detected dir.
return Driver.str();
}
// Now we have an absolute path, but it may be a symlink.
assert(llvm::sys::path::is_absolute(Driver));
if (FollowSymlink) {
llvm::SmallString<256> Resolved;
if (!llvm::sys::fs::real_path(Driver, Resolved))
return SiblingOf(Resolved);
}
return Driver.str();
}
} // namespace
CommandMangler CommandMangler::detect() {
CommandMangler Result;
Result.ClangPath = detectClangPath();
Result.ResourceDir = detectStandardResourceDir();
Result.Sysroot = detectSysroot();
return Result;
}
CommandMangler CommandMangler::forTests() {
return CommandMangler();
}
void CommandMangler::adjust(std::vector<std::string> &Cmd) const {
for (auto &Edit : Config::current().CompileFlags.Edits)
Edit(Cmd);
// Check whether the flag exists, either as -flag or -flag=*
auto Has = [&](llvm::StringRef Flag) {
for (llvm::StringRef Arg : Cmd) {
if (Arg.consume_front(Flag) && (Arg.empty() || Arg[0] == '='))
return true;
}
return false;
};
// clangd should not write files to disk, including dependency files
// requested on the command line.
Cmd = tooling::getClangStripDependencyFileAdjuster()(Cmd, "");
// Strip plugin related command line arguments. Clangd does
// not support plugins currently. Therefore it breaks if
// compiler tries to load plugins.
Cmd = tooling::getStripPluginsAdjuster()(Cmd, "");
Cmd = tooling::getClangSyntaxOnlyAdjuster()(Cmd, "");
std::vector<std::string> ToAppend;
if (ResourceDir && !Has("-resource-dir"))
ToAppend.push_back(("-resource-dir=" + *ResourceDir));
// Don't set `-isysroot` if it is already set or if `--sysroot` is set.
// `--sysroot` is a superset of the `-isysroot` argument.
if (Sysroot && !Has("-isysroot") && !Has("--sysroot")) {
ToAppend.push_back("-isysroot");
ToAppend.push_back(*Sysroot);
}
if (!ToAppend.empty()) {
Cmd = tooling::getInsertArgumentAdjuster(
std::move(ToAppend), tooling::ArgumentInsertPosition::END)(Cmd, "");
}
if (!Cmd.empty()) {
bool FollowSymlink = !Has("-no-canonical-prefixes");
Cmd.front() =
(FollowSymlink ? ResolvedDrivers : ResolvedDriversNoFollow)
.get(Cmd.front(), [&, this] {
return resolveDriver(Cmd.front(), FollowSymlink, ClangPath);
});
}
}
CommandMangler::operator clang::tooling::ArgumentsAdjuster() && {
// ArgumentsAdjuster is a std::function and so must be copyable.
return [Mangler = std::make_shared<CommandMangler>(std::move(*this))](
const std::vector<std::string> &Args, llvm::StringRef File) {
auto Result = Args;
Mangler->adjust(Result);
return Result;
};
}
// ArgStripper implementation
namespace {
// Determine total number of args consumed by this option.
// Return answers for {Exact, Prefix} match. 0 means not allowed.
std::pair<unsigned, unsigned> getArgCount(const llvm::opt::Option &Opt) {
constexpr static unsigned Rest = 10000; // Should be all the rest!
// Reference is llvm::opt::Option::acceptInternal()
using llvm::opt::Option;
switch (Opt.getKind()) {
case Option::FlagClass:
return {1, 0};
case Option::JoinedClass:
case Option::CommaJoinedClass:
return {1, 1};
case Option::GroupClass:
case Option::InputClass:
case Option::UnknownClass:
case Option::ValuesClass:
return {1, 0};
case Option::JoinedAndSeparateClass:
return {2, 2};
case Option::SeparateClass:
return {2, 0};
case Option::MultiArgClass:
return {1 + Opt.getNumArgs(), 0};
case Option::JoinedOrSeparateClass:
return {2, 1};
case Option::RemainingArgsClass:
return {Rest, 0};
case Option::RemainingArgsJoinedClass:
return {Rest, Rest};
}
llvm_unreachable("Unhandled option kind");
}
// Flag-parsing mode, which affects which flags are available.
enum DriverMode : unsigned char {
DM_None = 0,
DM_GCC = 1, // Default mode e.g. when invoked as 'clang'
DM_CL = 2, // MS CL.exe compatible mode e.g. when invoked as 'clang-cl'
DM_CC1 = 4, // When invoked as 'clang -cc1' or after '-Xclang'
DM_All = 7
};
// Examine args list to determine if we're in GCC, CL-compatible, or cc1 mode.
DriverMode getDriverMode(const std::vector<std::string> &Args) {
DriverMode Mode = DM_GCC;
llvm::StringRef Argv0 = Args.front();
if (Argv0.endswith_insensitive(".exe"))
Argv0 = Argv0.drop_back(strlen(".exe"));
if (Argv0.endswith_insensitive("cl"))
Mode = DM_CL;
for (const llvm::StringRef Arg : Args) {
if (Arg == "--driver-mode=cl") {
Mode = DM_CL;
break;
}
if (Arg == "-cc1") {
Mode = DM_CC1;
break;
}
}
return Mode;
}
// Returns the set of DriverModes where an option may be used.
unsigned char getModes(const llvm::opt::Option &Opt) {
// Why is this so complicated?!
// Reference is clang::driver::Driver::getIncludeExcludeOptionFlagMasks()
unsigned char Result = DM_None;
if (Opt.hasFlag(driver::options::CC1Option))
Result |= DM_CC1;
if (!Opt.hasFlag(driver::options::NoDriverOption)) {
if (Opt.hasFlag(driver::options::CLOption)) {
Result |= DM_CL;
} else {
Result |= DM_GCC;
if (Opt.hasFlag(driver::options::CoreOption)) {
Result |= DM_CL;
}
}
}
return Result;
}
} // namespace
llvm::ArrayRef<ArgStripper::Rule> ArgStripper::rulesFor(llvm::StringRef Arg) {
// All the hard work is done once in a static initializer.
// We compute a table containing strings to look for and #args to skip.
// e.g. "-x" => {-x 2 args, -x* 1 arg, --language 2 args, --language=* 1 arg}
using TableTy =
llvm::StringMap<llvm::SmallVector<Rule, 4>, llvm::BumpPtrAllocator>;
static TableTy *Table = [] {
auto &DriverTable = driver::getDriverOptTable();
using DriverID = clang::driver::options::ID;
// Collect sets of aliases, so we can treat -foo and -foo= as synonyms.
// Conceptually a double-linked list: PrevAlias[I] -> I -> NextAlias[I].
// If PrevAlias[I] is INVALID, then I is canonical.
DriverID PrevAlias[DriverID::LastOption] = {DriverID::OPT_INVALID};
DriverID NextAlias[DriverID::LastOption] = {DriverID::OPT_INVALID};
auto AddAlias = [&](DriverID Self, DriverID T) {
if (NextAlias[T]) {
PrevAlias[NextAlias[T]] = Self;
NextAlias[Self] = NextAlias[T];
}
PrevAlias[Self] = T;
NextAlias[T] = Self;
};
// Also grab prefixes for each option, these are not fully exposed.
const char *const *Prefixes[DriverID::LastOption] = {nullptr};
#define PREFIX(NAME, VALUE) static const char *const NAME[] = VALUE;
#define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS, PARAM, \
HELP, METAVAR, VALUES) \
if (DriverID::OPT_##ALIAS != DriverID::OPT_INVALID && ALIASARGS == nullptr) \
AddAlias(DriverID::OPT_##ID, DriverID::OPT_##ALIAS); \
Prefixes[DriverID::OPT_##ID] = PREFIX;
#include "clang/Driver/Options.inc"
#undef OPTION
#undef PREFIX
auto Result = std::make_unique<TableTy>();
// Iterate over distinct options (represented by the canonical alias).
// Every spelling of this option will get the same set of rules.
for (unsigned ID = 1 /*Skip INVALID */; ID < DriverID::LastOption; ++ID) {
if (PrevAlias[ID] || ID == DriverID::OPT_Xclang)
continue; // Not canonical, or specially handled.
llvm::SmallVector<Rule> Rules;
// Iterate over each alias, to add rules for parsing it.
for (unsigned A = ID; A != DriverID::OPT_INVALID; A = NextAlias[A]) {
if (Prefixes[A] == nullptr) // option groups.
continue;
auto Opt = DriverTable.getOption(A);
// Exclude - and -foo pseudo-options.
if (Opt.getName().empty())
continue;
auto Modes = getModes(Opt);
std::pair<unsigned, unsigned> ArgCount = getArgCount(Opt);
// Iterate over each spelling of the alias, e.g. -foo vs --foo.
for (auto *Prefix = Prefixes[A]; *Prefix != nullptr; ++Prefix) {
llvm::SmallString<64> Buf(*Prefix);
Buf.append(Opt.getName());
llvm::StringRef Spelling = Result->try_emplace(Buf).first->getKey();
Rules.emplace_back();
Rule &R = Rules.back();
R.Text = Spelling;
R.Modes = Modes;
R.ExactArgs = ArgCount.first;
R.PrefixArgs = ArgCount.second;
// Concrete priority is the index into the option table.
// Effectively, earlier entries take priority over later ones.
assert(ID < std::numeric_limits<decltype(R.Priority)>::max() &&
"Rules::Priority overflowed by options table");
R.Priority = ID;
}
}
// Register the set of rules under each possible name.
for (const auto &R : Rules)
Result->find(R.Text)->second.append(Rules.begin(), Rules.end());
}
#ifndef NDEBUG
// Dump the table and various measures of its size.
unsigned RuleCount = 0;
dlog("ArgStripper Option spelling table");
for (const auto &Entry : *Result) {
dlog("{0}", Entry.first());
RuleCount += Entry.second.size();
for (const auto &R : Entry.second)
dlog(" {0} #={1} *={2} Mode={3}", R.Text, R.ExactArgs, R.PrefixArgs,
int(R.Modes));
}
dlog("Table spellings={0} rules={1} string-bytes={2}", Result->size(),
RuleCount, Result->getAllocator().getBytesAllocated());
#endif
// The static table will never be destroyed.
return Result.release();
}();
auto It = Table->find(Arg);
return (It == Table->end()) ? llvm::ArrayRef<Rule>() : It->second;
}
void ArgStripper::strip(llvm::StringRef Arg) {
auto OptionRules = rulesFor(Arg);
if (OptionRules.empty()) {
// Not a recognized flag. Strip it literally.
Storage.emplace_back(Arg);
Rules.emplace_back();
Rules.back().Text = Storage.back();
Rules.back().ExactArgs = 1;
if (Rules.back().Text.consume_back("*"))
Rules.back().PrefixArgs = 1;
Rules.back().Modes = DM_All;
Rules.back().Priority = -1; // Max unsigned = lowest priority.
} else {
Rules.append(OptionRules.begin(), OptionRules.end());
}
}
const ArgStripper::Rule *ArgStripper::matchingRule(llvm::StringRef Arg,
unsigned Mode,
unsigned &ArgCount) const {
const ArgStripper::Rule *BestRule = nullptr;
for (const Rule &R : Rules) {
// Rule can fail to match if...
if (!(R.Modes & Mode))
continue; // not applicable to current driver mode
if (BestRule && BestRule->Priority < R.Priority)
continue; // lower-priority than best candidate.
if (!Arg.startswith(R.Text))
continue; // current arg doesn't match the prefix string
bool PrefixMatch = Arg.size() > R.Text.size();
// Can rule apply as an exact/prefix match?
if (unsigned Count = PrefixMatch ? R.PrefixArgs : R.ExactArgs) {
BestRule = &R;
ArgCount = Count;
}
// Continue in case we find a higher-priority rule.
}
return BestRule;
}
void ArgStripper::process(std::vector<std::string> &Args) const {
if (Args.empty())
return;
// We're parsing the args list in some mode (e.g. gcc-compatible) but may
// temporarily switch to another mode with the -Xclang flag.
DriverMode MainMode = getDriverMode(Args);
DriverMode CurrentMode = MainMode;
// Read and write heads for in-place deletion.
unsigned Read = 0, Write = 0;
bool WasXclang = false;
while (Read < Args.size()) {
unsigned ArgCount = 0;
if (matchingRule(Args[Read], CurrentMode, ArgCount)) {
// Delete it and its args.
if (WasXclang) {
assert(Write > 0);
--Write; // Drop previous -Xclang arg
CurrentMode = MainMode;
WasXclang = false;
}
// Advance to last arg. An arg may be foo or -Xclang foo.
for (unsigned I = 1; Read < Args.size() && I < ArgCount; ++I) {
++Read;
if (Read < Args.size() && Args[Read] == "-Xclang")
++Read;
}
} else {
// No match, just copy the arg through.
WasXclang = Args[Read] == "-Xclang";
CurrentMode = WasXclang ? DM_CC1 : MainMode;
if (Write != Read)
Args[Write] = std::move(Args[Read]);
++Write;
}
++Read;
}
Args.resize(Write);
}
std::string printArgv(llvm::ArrayRef<llvm::StringRef> Args) {
std::string Buf;
llvm::raw_string_ostream OS(Buf);
bool Sep = false;
for (llvm::StringRef Arg : Args) {
if (Sep)
OS << ' ';
Sep = true;
if (llvm::all_of(Arg, llvm::isPrint) &&
Arg.find_first_of(" \t\n\"\\") == llvm::StringRef::npos) {
OS << Arg;
continue;
}
OS << '"';
OS.write_escaped(Arg, /*UseHexEscapes=*/true);
OS << '"';
}
return std::move(OS.str());
}
std::string printArgv(llvm::ArrayRef<std::string> Args) {
std::vector<llvm::StringRef> Refs(Args.size());
llvm::copy(Args, Refs.begin());
return printArgv(Refs);
}
} // namespace clangd
} // namespace clang
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