Author: Haojian Wu Date: 2025-07-04T22:11:59+02:00 New Revision: e2510b189dae1a18c1e84ea69c99ff417950e03a
URL: https://github.com/llvm/llvm-project/commit/e2510b189dae1a18c1e84ea69c99ff417950e03a DIFF: https://github.com/llvm/llvm-project/commit/e2510b189dae1a18c1e84ea69c99ff417950e03a.diff LOG: [clang] SourceManager: Cache offsets for LastFileIDLookup to speed up getFileID (#146782) `getFileID` is a hot method. By caching the offset range in `LastFileIDLookup`, we can more quickly check whether a given offset falls within it, avoiding calling `isOffsetInFileID`. https://llvm-compile-time-tracker.com/compare.php?from=0588e8188c647460b641b09467fe6b13a8d510d5&to=64843a500f0191b79a8109da9acd7e80d961c7a3&stat=instructions:u Added: Modified: clang/include/clang/Basic/SourceManager.h clang/lib/Basic/SourceManager.cpp Removed: ################################################################################ diff --git a/clang/include/clang/Basic/SourceManager.h b/clang/include/clang/Basic/SourceManager.h index eefd4885534c8..a90cc70825ffd 100644 --- a/clang/include/clang/Basic/SourceManager.h +++ b/clang/include/clang/Basic/SourceManager.h @@ -767,6 +767,8 @@ class SourceManager : public RefCountedBase<SourceManager> { /// LastFileIDLookup records the last FileID looked up or created, because it /// is very common to look up many tokens from the same file. mutable FileID LastFileIDLookup; + mutable SourceLocation::UIntTy LastLookupStartOffset; + mutable SourceLocation::UIntTy LastLookupEndOffset; // exclude /// Holds information for \#line directives. /// @@ -1901,9 +1903,8 @@ class SourceManager : public RefCountedBase<SourceManager> { FileID getFileID(SourceLocation::UIntTy SLocOffset) const { // If our one-entry cache covers this offset, just return it. - if (isOffsetInFileID(LastFileIDLookup, SLocOffset)) + if (SLocOffset >= LastLookupStartOffset && SLocOffset < LastLookupEndOffset) return LastFileIDLookup; - return getFileIDSlow(SLocOffset); } diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp index 1b4be1414b5d4..7d1b23bbc3b2c 100644 --- a/clang/lib/Basic/SourceManager.cpp +++ b/clang/lib/Basic/SourceManager.cpp @@ -335,6 +335,7 @@ void SourceManager::clearIDTables() { LastLineNoFileIDQuery = FileID(); LastLineNoContentCache = nullptr; LastFileIDLookup = FileID(); + LastLookupStartOffset = LastLookupEndOffset = 0; IncludedLocMap.clear(); if (LineTable) @@ -630,9 +631,11 @@ FileID SourceManager::createFileIDImpl(ContentCache &File, StringRef Filename, LocalSLocEntryTable.push_back( SLocEntry::get(NextLocalOffset, FileInfo::get(IncludePos, File, FileCharacter, Filename))); + LastLookupStartOffset = NextLocalOffset; // We do a +1 here because we want a SourceLocation that means "the end of the // file", e.g. for the "no newline at the end of the file" diagnostic. NextLocalOffset += FileSize + 1; + LastLookupEndOffset = NextLocalOffset; updateSlocUsageStats(); // Set LastFileIDLookup to the newly created file. The next getFileID call is @@ -802,8 +805,9 @@ FileID SourceManager::getFileIDSlow(SourceLocation::UIntTy SLocOffset) const { /// loaded one. FileID SourceManager::getFileIDLocal(SourceLocation::UIntTy SLocOffset) const { assert(SLocOffset < NextLocalOffset && "Bad function choice"); - assert(SLocOffset >= LocalSLocEntryTable[0].getOffset() && + assert(SLocOffset >= LocalSLocEntryTable[0].getOffset() && SLocOffset > 0 && "Invalid SLocOffset"); + assert(LastFileIDLookup.ID >= 0 && "Only cache local file sloc entry"); // After the first and second level caches, I see two common sorts of // behavior: 1) a lot of searched FileID's are "near" the cached file @@ -823,13 +827,11 @@ FileID SourceManager::getFileIDLocal(SourceLocation::UIntTy SLocOffset) const { unsigned LessIndex = 0; // upper bound of the search range. unsigned GreaterIndex = LocalSLocEntryTable.size(); - if (LastFileIDLookup.ID >= 0) { - // Use the LastFileIDLookup to prune the search space. - if (LocalSLocEntryTable[LastFileIDLookup.ID].getOffset() < SLocOffset) - LessIndex = LastFileIDLookup.ID; - else - GreaterIndex = LastFileIDLookup.ID; - } + // Use the LastFileIDLookup to prune the search space. + if (LastLookupStartOffset < SLocOffset) + LessIndex = LastFileIDLookup.ID; + else + GreaterIndex = LastFileIDLookup.ID; // Find the FileID that contains this. unsigned NumProbes = 0; @@ -840,7 +842,12 @@ FileID SourceManager::getFileIDLocal(SourceLocation::UIntTy SLocOffset) const { FileID Res = FileID::get(int(GreaterIndex)); // Remember it. We have good locality across FileID lookups. LastFileIDLookup = Res; - NumLinearScans += NumProbes+1; + LastLookupStartOffset = LocalSLocEntryTable[GreaterIndex].getOffset(); + LastLookupEndOffset = + GreaterIndex + 1 >= LocalSLocEntryTable.size() + ? NextLocalOffset + : LocalSLocEntryTable[GreaterIndex + 1].getOffset(); + NumLinearScans += NumProbes + 1; return Res; } if (++NumProbes == 8) @@ -864,6 +871,8 @@ FileID SourceManager::getFileIDLocal(SourceLocation::UIntTy SLocOffset) const { // At this point, LessIndex is the index of the *first element greater than* // SLocOffset. The element we are actually looking for is the one immediately // before it. + LastLookupStartOffset = LocalSLocEntryTable[LessIndex - 1].getOffset(); + LastLookupEndOffset = LocalSLocEntryTable[LessIndex].getOffset(); return LastFileIDLookup = FileID::get(LessIndex - 1); } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
