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

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//===--- SourceCode.h - Manipulating source code as strings -----*- C++ -*-===//
//
// 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 "SourceCode.h"
#include "Context.h"
#include "FuzzyMatch.h"
#include "Logger.h"
#include "Protocol.h"
#include "clang/AST/ASTContext.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Format/Format.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/Preprocessor.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/xxhash.h"
#include <algorithm>
namespace clang {
namespace clangd {
// Here be dragons. LSP positions use columns measured in *UTF-16 code units*!
// Clangd uses UTF-8 and byte-offsets internally, so conversion is nontrivial.
// Iterates over unicode codepoints in the (UTF-8) string. For each,
// invokes CB(UTF-8 length, UTF-16 length), and breaks if it returns true.
// Returns true if CB returned true, false if we hit the end of string.
template <typename Callback>
static bool iterateCodepoints(llvm::StringRef U8, const Callback &CB) {
// A codepoint takes two UTF-16 code unit if it's astral (outside BMP).
// Astral codepoints are encoded as 4 bytes in UTF-8, starting with 11110xxx.
for (size_t I = 0; I < U8.size();) {
unsigned char C = static_cast<unsigned char>(U8[I]);
if (LLVM_LIKELY(!(C & 0x80))) { // ASCII character.
if (CB(1, 1))
return true;
++I;
continue;
}
// This convenient property of UTF-8 holds for all non-ASCII characters.
size_t UTF8Length = llvm::countLeadingOnes(C);
// 0xxx is ASCII, handled above. 10xxx is a trailing byte, invalid here.
// 11111xxx is not valid UTF-8 at all. Assert because it's probably our bug.
assert((UTF8Length >= 2 && UTF8Length <= 4) &&
"Invalid UTF-8, or transcoding bug?");
I += UTF8Length; // Skip over all trailing bytes.
// A codepoint takes two UTF-16 code unit if it's astral (outside BMP).
// Astral codepoints are encoded as 4 bytes in UTF-8 (11110xxx ...)
if (CB(UTF8Length, UTF8Length == 4 ? 2 : 1))
return true;
}
return false;
}
// Returns the byte offset into the string that is an offset of \p Units in
// the specified encoding.
// Conceptually, this converts to the encoding, truncates to CodeUnits,
// converts back to UTF-8, and returns the length in bytes.
static size_t measureUnits(llvm::StringRef U8, int Units, OffsetEncoding Enc,
bool &Valid) {
Valid = Units >= 0;
if (Units <= 0)
return 0;
size_t Result = 0;
switch (Enc) {
case OffsetEncoding::UTF8:
Result = Units;
break;
case OffsetEncoding::UTF16:
Valid = iterateCodepoints(U8, [&](int U8Len, int U16Len) {
Result += U8Len;
Units -= U16Len;
return Units <= 0;
});
if (Units < 0) // Offset in the middle of a surrogate pair.
Valid = false;
break;
case OffsetEncoding::UTF32:
Valid = iterateCodepoints(U8, [&](int U8Len, int U16Len) {
Result += U8Len;
Units--;
return Units <= 0;
});
break;
case OffsetEncoding::UnsupportedEncoding:
llvm_unreachable("unsupported encoding");
}
// Don't return an out-of-range index if we overran.
if (Result > U8.size()) {
Valid = false;
return U8.size();
}
return Result;
}
Key<OffsetEncoding> kCurrentOffsetEncoding;
static OffsetEncoding lspEncoding() {
auto *Enc = Context::current().get(kCurrentOffsetEncoding);
return Enc ? *Enc : OffsetEncoding::UTF16;
}
// Like most strings in clangd, the input is UTF-8 encoded.
size_t lspLength(llvm::StringRef Code) {
size_t Count = 0;
switch (lspEncoding()) {
case OffsetEncoding::UTF8:
Count = Code.size();
break;
case OffsetEncoding::UTF16:
iterateCodepoints(Code, [&](int U8Len, int U16Len) {
Count += U16Len;
return false;
});
break;
case OffsetEncoding::UTF32:
iterateCodepoints(Code, [&](int U8Len, int U16Len) {
++Count;
return false;
});
break;
case OffsetEncoding::UnsupportedEncoding:
llvm_unreachable("unsupported encoding");
}
return Count;
}
llvm::Expected<size_t> positionToOffset(llvm::StringRef Code, Position P,
bool AllowColumnsBeyondLineLength) {
if (P.line < 0)
return llvm::make_error<llvm::StringError>(
llvm::formatv("Line value can't be negative ({0})", P.line),
llvm::errc::invalid_argument);
if (P.character < 0)
return llvm::make_error<llvm::StringError>(
llvm::formatv("Character value can't be negative ({0})", P.character),
llvm::errc::invalid_argument);
size_t StartOfLine = 0;
for (int I = 0; I != P.line; ++I) {
size_t NextNL = Code.find('\n', StartOfLine);
if (NextNL == llvm::StringRef::npos)
return llvm::make_error<llvm::StringError>(
llvm::formatv("Line value is out of range ({0})", P.line),
llvm::errc::invalid_argument);
StartOfLine = NextNL + 1;
}
StringRef Line =
Code.substr(StartOfLine).take_until([](char C) { return C == '\n'; });
// P.character may be in UTF-16, transcode if necessary.
bool Valid;
size_t ByteInLine = measureUnits(Line, P.character, lspEncoding(), Valid);
if (!Valid && !AllowColumnsBeyondLineLength)
return llvm::make_error<llvm::StringError>(
llvm::formatv("{0} offset {1} is invalid for line {2}", lspEncoding(),
P.character, P.line),
llvm::errc::invalid_argument);
return StartOfLine + ByteInLine;
}
Position offsetToPosition(llvm::StringRef Code, size_t Offset) {
Offset = std::min(Code.size(), Offset);
llvm::StringRef Before = Code.substr(0, Offset);
int Lines = Before.count('\n');
size_t PrevNL = Before.rfind('\n');
size_t StartOfLine = (PrevNL == llvm::StringRef::npos) ? 0 : (PrevNL + 1);
Position Pos;
Pos.line = Lines;
Pos.character = lspLength(Before.substr(StartOfLine));
return Pos;
}
Position sourceLocToPosition(const SourceManager &SM, SourceLocation Loc) {
// We use the SourceManager's line tables, but its column number is in bytes.
FileID FID;
unsigned Offset;
std::tie(FID, Offset) = SM.getDecomposedSpellingLoc(Loc);
Position P;
P.line = static_cast<int>(SM.getLineNumber(FID, Offset)) - 1;
bool Invalid = false;
llvm::StringRef Code = SM.getBufferData(FID, &Invalid);
if (!Invalid) {
auto ColumnInBytes = SM.getColumnNumber(FID, Offset) - 1;
auto LineSoFar = Code.substr(Offset - ColumnInBytes, ColumnInBytes);
P.character = lspLength(LineSoFar);
}
return P;
}
llvm::Optional<Range> getTokenRange(const SourceManager &SM,
const LangOptions &LangOpts,
SourceLocation TokLoc) {
if (!TokLoc.isValid())
return llvm::None;
SourceLocation End = Lexer::getLocForEndOfToken(TokLoc, 0, SM, LangOpts);
if (!End.isValid())
return llvm::None;
return halfOpenToRange(SM, CharSourceRange::getCharRange(TokLoc, End));
}
bool isValidFileRange(const SourceManager &Mgr, SourceRange R) {
if (!R.getBegin().isValid() || !R.getEnd().isValid())
return false;
FileID BeginFID;
size_t BeginOffset = 0;
std::tie(BeginFID, BeginOffset) = Mgr.getDecomposedLoc(R.getBegin());
FileID EndFID;
size_t EndOffset = 0;
std::tie(EndFID, EndOffset) = Mgr.getDecomposedLoc(R.getEnd());
return BeginFID.isValid() && BeginFID == EndFID && BeginOffset <= EndOffset;
}
bool halfOpenRangeContains(const SourceManager &Mgr, SourceRange R,
SourceLocation L) {
assert(isValidFileRange(Mgr, R));
FileID BeginFID;
size_t BeginOffset = 0;
std::tie(BeginFID, BeginOffset) = Mgr.getDecomposedLoc(R.getBegin());
size_t EndOffset = Mgr.getFileOffset(R.getEnd());
FileID LFid;
size_t LOffset;
std::tie(LFid, LOffset) = Mgr.getDecomposedLoc(L);
return BeginFID == LFid && BeginOffset <= LOffset && LOffset < EndOffset;
}
bool halfOpenRangeTouches(const SourceManager &Mgr, SourceRange R,
SourceLocation L) {
return L == R.getEnd() || halfOpenRangeContains(Mgr, R, L);
}
llvm::Optional<SourceRange> toHalfOpenFileRange(const SourceManager &Mgr,
const LangOptions &LangOpts,
SourceRange R) {
auto Begin = Mgr.getFileLoc(R.getBegin());
if (Begin.isInvalid())
return llvm::None;
auto End = Mgr.getFileLoc(R.getEnd());
if (End.isInvalid())
return llvm::None;
End = Lexer::getLocForEndOfToken(End, 0, Mgr, LangOpts);
SourceRange Result(Begin, End);
if (!isValidFileRange(Mgr, Result))
return llvm::None;
return Result;
}
llvm::StringRef toSourceCode(const SourceManager &SM, SourceRange R) {
assert(isValidFileRange(SM, R));
bool Invalid = false;
auto *Buf = SM.getBuffer(SM.getFileID(R.getBegin()), &Invalid);
assert(!Invalid);
size_t BeginOffset = SM.getFileOffset(R.getBegin());
size_t EndOffset = SM.getFileOffset(R.getEnd());
return Buf->getBuffer().substr(BeginOffset, EndOffset - BeginOffset);
}
llvm::Expected<SourceLocation> sourceLocationInMainFile(const SourceManager &SM,
Position P) {
llvm::StringRef Code = SM.getBuffer(SM.getMainFileID())->getBuffer();
auto Offset =
positionToOffset(Code, P, /*AllowColumnBeyondLineLength=*/false);
if (!Offset)
return Offset.takeError();
return SM.getLocForStartOfFile(SM.getMainFileID()).getLocWithOffset(*Offset);
}
Range halfOpenToRange(const SourceManager &SM, CharSourceRange R) {
// Clang is 1-based, LSP uses 0-based indexes.
Position Begin = sourceLocToPosition(SM, R.getBegin());
Position End = sourceLocToPosition(SM, R.getEnd());
return {Begin, End};
}
std::pair<size_t, size_t> offsetToClangLineColumn(llvm::StringRef Code,
size_t Offset) {
Offset = std::min(Code.size(), Offset);
llvm::StringRef Before = Code.substr(0, Offset);
int Lines = Before.count('\n');
size_t PrevNL = Before.rfind('\n');
size_t StartOfLine = (PrevNL == llvm::StringRef::npos) ? 0 : (PrevNL + 1);
return {Lines + 1, Offset - StartOfLine + 1};
}
std::pair<StringRef, StringRef> splitQualifiedName(StringRef QName) {
size_t Pos = QName.rfind("::");
if (Pos == llvm::StringRef::npos)
return {llvm::StringRef(), QName};
return {QName.substr(0, Pos + 2), QName.substr(Pos + 2)};
}
TextEdit replacementToEdit(llvm::StringRef Code,
const tooling::Replacement &R) {
Range ReplacementRange = {
offsetToPosition(Code, R.getOffset()),
offsetToPosition(Code, R.getOffset() + R.getLength())};
return {ReplacementRange, R.getReplacementText()};
}
std::vector<TextEdit> replacementsToEdits(llvm::StringRef Code,
const tooling::Replacements &Repls) {
std::vector<TextEdit> Edits;
for (const auto &R : Repls)
Edits.push_back(replacementToEdit(Code, R));
return Edits;
}
llvm::Optional<std::string> getCanonicalPath(const FileEntry *F,
const SourceManager &SourceMgr) {
if (!F)
return None;
llvm::SmallString<128> FilePath = F->getName();
if (!llvm::sys::path::is_absolute(FilePath)) {
if (auto EC =
SourceMgr.getFileManager().getVirtualFileSystem().makeAbsolute(
FilePath)) {
elog("Could not turn relative path '{0}' to absolute: {1}", FilePath,
EC.message());
return None;
}
}
// Handle the symbolic link path case where the current working directory
// (getCurrentWorkingDirectory) is a symlink./ We always want to the real
// file path (instead of the symlink path) for the C++ symbols.
//
// Consider the following example:
//
// src dir: /project/src/foo.h
// current working directory (symlink): /tmp/build -> /project/src/
//
// The file path of Symbol is "/project/src/foo.h" instead of
// "/tmp/build/foo.h"
if (const DirectoryEntry *Dir = SourceMgr.getFileManager().getDirectory(
llvm::sys::path::parent_path(FilePath))) {
llvm::SmallString<128> RealPath;
llvm::StringRef DirName = SourceMgr.getFileManager().getCanonicalName(Dir);
llvm::sys::path::append(RealPath, DirName,
llvm::sys::path::filename(FilePath));
return RealPath.str().str();
}
return FilePath.str().str();
}
TextEdit toTextEdit(const FixItHint &FixIt, const SourceManager &M,
const LangOptions &L) {
TextEdit Result;
Result.range =
halfOpenToRange(M, Lexer::makeFileCharRange(FixIt.RemoveRange, M, L));
Result.newText = FixIt.CodeToInsert;
return Result;
}
bool isRangeConsecutive(const Range &Left, const Range &Right) {
return Left.end.line == Right.start.line &&
Left.end.character == Right.start.character;
}
FileDigest digest(llvm::StringRef Content) {
uint64_t Hash{llvm::xxHash64(Content)};
FileDigest Result;
for (unsigned I = 0; I < Result.size(); ++I) {
Result[I] = uint8_t(Hash);
Hash >>= 8;
}
return Result;
}
llvm::Optional<FileDigest> digestFile(const SourceManager &SM, FileID FID) {
bool Invalid = false;
llvm::StringRef Content = SM.getBufferData(FID, &Invalid);
if (Invalid)
return None;
return digest(Content);
}
format::FormatStyle getFormatStyleForFile(llvm::StringRef File,
llvm::StringRef Content,
llvm::vfs::FileSystem *FS) {
auto Style = format::getStyle(format::DefaultFormatStyle, File,
format::DefaultFallbackStyle, Content, FS);
if (!Style) {
log("getStyle() failed for file {0}: {1}. Fallback is LLVM style.", File,
Style.takeError());
Style = format::getLLVMStyle();
}
return *Style;
}
llvm::Expected<tooling::Replacements>
cleanupAndFormat(StringRef Code, const tooling::Replacements &Replaces,
const format::FormatStyle &Style) {
auto CleanReplaces = cleanupAroundReplacements(Code, Replaces, Style);
if (!CleanReplaces)
return CleanReplaces;
return formatReplacements(Code, std::move(*CleanReplaces), Style);
}
template <typename Action>
static void lex(llvm::StringRef Code, const format::FormatStyle &Style,
Action A) {
// FIXME: InMemoryFileAdapter crashes unless the buffer is null terminated!
std::string NullTerminatedCode = Code.str();
SourceManagerForFile FileSM("dummy.cpp", NullTerminatedCode);
auto &SM = FileSM.get();
auto FID = SM.getMainFileID();
Lexer Lex(FID, SM.getBuffer(FID), SM, format::getFormattingLangOpts(Style));
Token Tok;
while (!Lex.LexFromRawLexer(Tok))
A(Tok);
}
llvm::StringMap<unsigned> collectIdentifiers(llvm::StringRef Content,
const format::FormatStyle &Style) {
llvm::StringMap<unsigned> Identifiers;
lex(Content, Style, [&](const clang::Token &Tok) {
switch (Tok.getKind()) {
case tok::identifier:
++Identifiers[Tok.getIdentifierInfo()->getName()];
break;
case tok::raw_identifier:
++Identifiers[Tok.getRawIdentifier()];
break;
default:
break;
}
});
return Identifiers;
}
namespace {
enum NamespaceEvent {
BeginNamespace, // namespace <ns> {. Payload is resolved <ns>.
EndNamespace, // } // namespace <ns>. Payload is resolved *outer* namespace.
UsingDirective // using namespace <ns>. Payload is unresolved <ns>.
};
// Scans C++ source code for constructs that change the visible namespaces.
void parseNamespaceEvents(
llvm::StringRef Code, const format::FormatStyle &Style,
llvm::function_ref<void(NamespaceEvent, llvm::StringRef)> Callback) {
// Stack of enclosing namespaces, e.g. {"clang", "clangd"}
std::vector<std::string> Enclosing; // Contains e.g. "clang", "clangd"
// Stack counts open braces. true if the brace opened a namespace.
std::vector<bool> BraceStack;
enum {
Default,
Namespace, // just saw 'namespace'
NamespaceName, // just saw 'namespace' NSName
Using, // just saw 'using'
UsingNamespace, // just saw 'using namespace'
UsingNamespaceName, // just saw 'using namespace' NSName
} State = Default;
std::string NSName;
lex(Code, Style, [&](const clang::Token &Tok) {
switch(Tok.getKind()) {
case tok::raw_identifier:
// In raw mode, this could be a keyword or a name.
switch (State) {
case UsingNamespace:
case UsingNamespaceName:
NSName.append(Tok.getRawIdentifier());
State = UsingNamespaceName;
break;
case Namespace:
case NamespaceName:
NSName.append(Tok.getRawIdentifier());
State = NamespaceName;
break;
case Using:
State =
(Tok.getRawIdentifier() == "namespace") ? UsingNamespace : Default;
break;
case Default:
NSName.clear();
if (Tok.getRawIdentifier() == "namespace")
State = Namespace;
else if (Tok.getRawIdentifier() == "using")
State = Using;
break;
}
break;
case tok::coloncolon:
// This can come at the beginning or in the middle of a namespace name.
switch (State) {
case UsingNamespace:
case UsingNamespaceName:
NSName.append("::");
State = UsingNamespaceName;
break;
case NamespaceName:
NSName.append("::");
State = NamespaceName;
break;
case Namespace: // Not legal here.
case Using:
case Default:
State = Default;
break;
}
break;
case tok::l_brace:
// Record which { started a namespace, so we know when } ends one.
if (State == NamespaceName) {
// Parsed: namespace <name> {
BraceStack.push_back(true);
Enclosing.push_back(NSName);
Callback(BeginNamespace, llvm::join(Enclosing, "::"));
} else {
// This case includes anonymous namespaces (State = Namespace).
// For our purposes, they're not namespaces and we ignore them.
BraceStack.push_back(false);
}
State = Default;
break;
case tok::r_brace:
// If braces are unmatched, we're going to be confused, but don't crash.
if (!BraceStack.empty()) {
if (BraceStack.back()) {
// Parsed: } // namespace
Enclosing.pop_back();
Callback(EndNamespace, llvm::join(Enclosing, "::"));
}
BraceStack.pop_back();
}
break;
case tok::semi:
if (State == UsingNamespaceName)
// Parsed: using namespace <name> ;
Callback(UsingDirective, llvm::StringRef(NSName));
State = Default;
break;
default:
State = Default;
break;
}
});
}
// Returns the prefix namespaces of NS: {"" ... NS}.
llvm::SmallVector<llvm::StringRef, 8> ancestorNamespaces(llvm::StringRef NS) {
llvm::SmallVector<llvm::StringRef, 8> Results;
Results.push_back(NS.take_front(0));
NS.split(Results, "::", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
for (llvm::StringRef &R : Results)
R = NS.take_front(R.end() - NS.begin());
return Results;
}
} // namespace
std::vector<std::string> visibleNamespaces(llvm::StringRef Code,
const format::FormatStyle &Style) {
std::string Current;
// Map from namespace to (resolved) namespaces introduced via using directive.
llvm::StringMap<llvm::StringSet<>> UsingDirectives;
parseNamespaceEvents(Code, Style,
[&](NamespaceEvent Event, llvm::StringRef NS) {
switch (Event) {
case BeginNamespace:
case EndNamespace:
Current = NS;
break;
case UsingDirective:
if (NS.consume_front("::"))
UsingDirectives[Current].insert(NS);
else {
for (llvm::StringRef Enclosing :
ancestorNamespaces(Current)) {
if (Enclosing.empty())
UsingDirectives[Current].insert(NS);
else
UsingDirectives[Current].insert(
(Enclosing + "::" + NS).str());
}
}
break;
}
});
std::vector<std::string> Found;
for (llvm::StringRef Enclosing : ancestorNamespaces(Current)) {
Found.push_back(Enclosing);
auto It = UsingDirectives.find(Enclosing);
if (It != UsingDirectives.end())
for (const auto& Used : It->second)
Found.push_back(Used.getKey());
}
llvm::sort(Found, [&](const std::string &LHS, const std::string &RHS) {
if (Current == RHS)
return false;
if (Current == LHS)
return true;
return LHS < RHS;
});
Found.erase(std::unique(Found.begin(), Found.end()), Found.end());
return Found;
}
llvm::StringSet<> collectWords(llvm::StringRef Content) {
// We assume short words are not significant.
// We may want to consider other stopwords, e.g. language keywords.
// (A very naive implementation showed no benefit, but lexing might do better)
static constexpr int MinWordLength = 4;
std::vector<CharRole> Roles(Content.size());
calculateRoles(Content, Roles);
llvm::StringSet<> Result;
llvm::SmallString<256> Word;
auto Flush = [&] {
if (Word.size() >= MinWordLength) {
for (char &C : Word)
C = llvm::toLower(C);
Result.insert(Word);
}
Word.clear();
};
for (unsigned I = 0; I < Content.size(); ++I) {
switch (Roles[I]) {
case Head:
Flush();
LLVM_FALLTHROUGH;
case Tail:
Word.push_back(Content[I]);
break;
case Unknown:
case Separator:
Flush();
break;
}
}
Flush();
return Result;
}
llvm::Optional<DefinedMacro> locateMacroAt(SourceLocation Loc,
Preprocessor &PP) {
const auto &SM = PP.getSourceManager();
const auto &LangOpts = PP.getLangOpts();
Token Result;
if (Lexer::getRawToken(SM.getSpellingLoc(Loc), Result, SM, LangOpts, false))
return None;
if (Result.is(tok::raw_identifier))
PP.LookUpIdentifierInfo(Result);
IdentifierInfo *IdentifierInfo = Result.getIdentifierInfo();
if (!IdentifierInfo || !IdentifierInfo->hadMacroDefinition())
return None;
std::pair<FileID, unsigned int> DecLoc = SM.getDecomposedExpansionLoc(Loc);
// Get the definition just before the searched location so that a macro
// referenced in a '#undef MACRO' can still be found.
SourceLocation BeforeSearchedLocation =
SM.getMacroArgExpandedLocation(SM.getLocForStartOfFile(DecLoc.first)
.getLocWithOffset(DecLoc.second - 1));
MacroDefinition MacroDef =
PP.getMacroDefinitionAtLoc(IdentifierInfo, BeforeSearchedLocation);
if (auto *MI = MacroDef.getMacroInfo())
return DefinedMacro{IdentifierInfo->getName(), MI};
return None;
}
} // namespace clangd
} // namespace clang
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