Reapply "Avoid emitting redundant or unusable directories in DIFile metadata entries.""
This reverts commit r348280 and reapplies D55085 without modifications.
Original commit message:
Avoid emitting redundant or unusable directories in DIFile metadata entries.
As discussed on llvm-dev recently, Clang currently emits redundant
directories in DIFile entries, such as
.file 1 "/Volumes/Data/llvm" "/Volumes/Data/llvm/tools/clang/test/CodeGen/debug-info-abspath.c"
This patch looks at any common prefix between the compilation
directory and the (absolute) file path and strips the redundant
part. More importantly it leaves the compilation directory empty if
the two paths have no common prefix.
After this patch the above entry is (assuming a compilation dir of "/Volumes/Data/llvm/_build"):
.file 1 "/Volumes/Data/llvm" "tools/clang/test/CodeGen/debug-info-abspath.c"
When building the FileCheck binary with debug info, this patch makes
the build artifacts ~1kb smaller.
Differential Revision: https://reviews.llvm.org/D55085
llvm-svn: 348513
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 3492fba..c556996 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -181,8 +181,7 @@
SourceManager &SM = CGM.getContext().getSourceManager();
auto *Scope = cast<llvm::DIScope>(LexicalBlockStack.back());
PresumedLoc PCLoc = SM.getPresumedLoc(CurLoc);
-
- if (PCLoc.isInvalid() || Scope->getFilename() == PCLoc.getFilename())
+ if (PCLoc.isInvalid() || Scope->getFile() == getOrCreateFile(CurLoc))
return;
if (auto *LBF = dyn_cast<llvm::DILexicalBlockFile>(Scope)) {
@@ -410,13 +409,13 @@
SourceManager &SM = CGM.getContext().getSourceManager();
PresumedLoc PLoc = SM.getPresumedLoc(Loc);
- if (PLoc.isInvalid() || StringRef(PLoc.getFilename()).empty())
+ StringRef FileName = PLoc.getFilename();
+ if (PLoc.isInvalid() || FileName.empty())
// If the location is not valid then use main input file.
return getOrCreateMainFile();
// Cache the results.
- const char *fname = PLoc.getFilename();
- auto It = DIFileCache.find(fname);
+ auto It = DIFileCache.find(FileName.data());
if (It != DIFileCache.end()) {
// Verify that the information still exists.
@@ -431,11 +430,41 @@
if (CSKind)
CSInfo.emplace(*CSKind, Checksum);
- llvm::DIFile *F = DBuilder.createFile(
- remapDIPath(PLoc.getFilename()), remapDIPath(getCurrentDirname()), CSInfo,
- getSource(SM, SM.getFileID(Loc)));
+ StringRef Dir;
+ StringRef File;
+ std::string RemappedFile = remapDIPath(FileName);
+ std::string CurDir = remapDIPath(getCurrentDirname());
+ SmallString<128> DirBuf;
+ SmallString<128> FileBuf;
+ if (llvm::sys::path::is_absolute(RemappedFile)) {
+ // Strip the common prefix (if it is more than just "/") from current
+ // directory and FileName for a more space-efficient encoding.
+ auto FileIt = llvm::sys::path::begin(RemappedFile);
+ auto FileE = llvm::sys::path::end(RemappedFile);
+ auto CurDirIt = llvm::sys::path::begin(CurDir);
+ auto CurDirE = llvm::sys::path::end(CurDir);
+ for (; CurDirIt != CurDirE && *CurDirIt == *FileIt; ++CurDirIt, ++FileIt)
+ llvm::sys::path::append(DirBuf, *CurDirIt);
+ if (std::distance(llvm::sys::path::begin(CurDir), CurDirIt) == 1) {
+ // The common prefix only the root; stripping it would cause
+ // LLVM diagnostic locations to be more confusing.
+ Dir = {};
+ File = RemappedFile;
+ } else {
+ for (; FileIt != FileE; ++FileIt)
+ llvm::sys::path::append(FileBuf, *FileIt);
+ Dir = DirBuf;
+ File = FileBuf;
+ }
+ } else {
+ Dir = CurDir;
+ File = RemappedFile;
+ }
+ llvm::DIFile *F =
+ DBuilder.createFile(File, Dir, CSInfo,
+ getSource(SM, SM.getFileID(Loc)));
- DIFileCache[fname].reset(F);
+ DIFileCache[FileName.data()].reset(F);
return F;
}