https://github.com/hokein updated
https://github.com/llvm/llvm-project/pull/146604
>From 7b06dabcc8fafee1e9ff3261264c36a44cb7b0a3 Mon Sep 17 00:00:00 2001
From: Haojian Wu
Date: Tue, 1 Jul 2025 22:04:51 +0200
Subject: [PATCH] [SourceManager] Speedup getFileIDLocal with a separate Offset
Table.
More cache friendly.
---
clang/include/clang/Basic/SourceManager.h | 2 ++
clang/lib/Basic/SourceManager.cpp | 16 +---
2 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/clang/include/clang/Basic/SourceManager.h
b/clang/include/clang/Basic/SourceManager.h
index a90cc70825ffd..ed967fd47dc83 100644
--- a/clang/include/clang/Basic/SourceManager.h
+++ b/clang/include/clang/Basic/SourceManager.h
@@ -719,6 +719,8 @@ class SourceManager : public RefCountedBase {
/// Positive FileIDs are indexes into this table. Entry 0 indicates an
invalid
/// expansion.
SmallVector LocalSLocEntryTable;
+ /// An in-parallel offset table, merely used for speeding up FileID lookup.
+ SmallVector LocalLocOffsetTable;
/// The table of SLocEntries that are loaded from other modules.
///
diff --git a/clang/lib/Basic/SourceManager.cpp
b/clang/lib/Basic/SourceManager.cpp
index 7d1b23bbc3b2c..79a0d9d28c40b 100644
--- a/clang/lib/Basic/SourceManager.cpp
+++ b/clang/lib/Basic/SourceManager.cpp
@@ -329,6 +329,7 @@ SourceManager::~SourceManager() {
void SourceManager::clearIDTables() {
MainFileID = FileID();
LocalSLocEntryTable.clear();
+ LocalLocOffsetTable.clear();
LoadedSLocEntryTable.clear();
SLocEntryLoaded.clear();
SLocEntryOffsetLoaded.clear();
@@ -628,9 +629,11 @@ FileID SourceManager::createFileIDImpl(ContentCache &File,
StringRef Filename,
noteSLocAddressSpaceUsage(Diag);
return FileID();
}
+ assert(LocalSLocEntryTable.size() == LocalLocOffsetTable.size());
LocalSLocEntryTable.push_back(
SLocEntry::get(NextLocalOffset,
FileInfo::get(IncludePos, File, FileCharacter,
Filename)));
+ LocalLocOffsetTable.push_back(NextLocalOffset);
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.
@@ -684,7 +687,9 @@ SourceManager::createExpansionLocImpl(const ExpansionInfo
&Info,
SLocEntryLoaded[Index] = SLocEntryOffsetLoaded[Index] = true;
return SourceLocation::getMacroLoc(LoadedOffset);
}
+ assert(LocalSLocEntryTable.size() == LocalLocOffsetTable.size());
LocalSLocEntryTable.push_back(SLocEntry::get(NextLocalOffset, Info));
+ LocalLocOffsetTable.push_back(NextLocalOffset);
if (NextLocalOffset + Length + 1 <= NextLocalOffset ||
NextLocalOffset + Length + 1 > CurrentLoadedOffset) {
Diag.Report(diag::err_sloc_space_too_large);
@@ -807,6 +812,7 @@ FileID SourceManager::getFileIDLocal(SourceLocation::UIntTy
SLocOffset) const {
assert(SLocOffset < NextLocalOffset && "Bad function choice");
assert(SLocOffset >= LocalSLocEntryTable[0].getOffset() && SLocOffset > 0 &&
"Invalid SLocOffset");
+ assert(LocalSLocEntryTable.size() == LocalLocOffsetTable.size());
assert(LastFileIDLookup.ID >= 0 && "Only cache local file sloc entry");
// After the first and second level caches, I see two common sorts of
@@ -837,8 +843,8 @@ FileID SourceManager::getFileIDLocal(SourceLocation::UIntTy
SLocOffset) const {
unsigned NumProbes = 0;
while (true) {
--GreaterIndex;
-assert(GreaterIndex < LocalSLocEntryTable.size());
-if (LocalSLocEntryTable[GreaterIndex].getOffset() <= SLocOffset) {
+assert(GreaterIndex < LocalLocOffsetTable.size());
+if (LocalLocOffsetTable[GreaterIndex] <= SLocOffset) {
FileID Res = FileID::get(int(GreaterIndex));
// Remember it. We have good locality across FileID lookups.
LastFileIDLookup = Res;
@@ -858,11 +864,7 @@ FileID
SourceManager::getFileIDLocal(SourceLocation::UIntTy SLocOffset) const {
++NumBinaryProbes;
unsigned MiddleIndex = LessIndex + (GreaterIndex - LessIndex) / 2;
-
-SourceLocation::UIntTy MidOffset =
-LocalSLocEntryTable[MiddleIndex].getOffset();
-
-if (MidOffset <= SLocOffset)
+if (LocalLocOffsetTable[MiddleIndex] <= SLocOffset)
LessIndex = MiddleIndex + 1;
else
GreaterIndex = MiddleIndex;
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