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Cache FileID when translating diagnostics in PCH files 

Modules/preambles/PCH files can contain diagnostics, which, when used,
are added to the current ASTUnit. For that to work, they are translated
to use the current FileManager's FileIDs. When the entry is not the
main file, all local source locations will be checked by a linear
search. Now this is a problem, when there are lots of diagnostics (say,
25000) and lots of local source locations (say, 440000), and end up
taking seconds when using such a preamble.

The fix is to cache the last FileID, because many subsequent diagnostics
refer to the same file. This reduces the time spent in
ASTUnit::TranslateStoredDiagnostics from seconds to a few milliseconds
for files with many slocs/diagnostics.

This fixes PR31353.
Differential Revision: https://reviews.llvm.org/D29755

llvm-svn: 295301
This commit is contained in:
Erik Verbruggen 2017-02-16 09:49:30 +00:00
parent 21c3d8e0fc
commit 2c7c38d9bb
1 changed files with 6 additions and 1 deletions
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7
clang/lib/Frontend/ASTUnit.cpp
View File

@ -2541,6 +2541,8 @@ void ASTUnit::TranslateStoredDiagnostics(
SmallVector<StoredDiagnostic, 4> Result;
Result.reserve(Diags.size());
const FileEntry *PreviousFE = nullptr;
FileID FID;
for (const StandaloneDiagnostic &SD : Diags) {
// Rebuild the StoredDiagnostic.
if (SD.Filename.empty())
@ -2548,7 +2550,10 @@ void ASTUnit::TranslateStoredDiagnostics(
const FileEntry *FE = FileMgr.getFile(SD.Filename);
if (!FE)
continue;
FileID FID = SrcMgr.translateFile(FE);
if (FE != PreviousFE) {
FID = SrcMgr.translateFile(FE);
PreviousFE = FE;
}
SourceLocation FileLoc = SrcMgr.getLocForStartOfFile(FID);
if (FileLoc.isInvalid())
continue;