Revert "Reland [clang] Canonicalize system headers in dependency file when -canonical-prefixes" (#71697)

This reverts commit 578a4716f549167165a2ec3bac89c86706136d4e.

This causes multiple issues. Compile time slowdown due to more path
canonicalization, and weird behavior on Windows.

Will reland under a separate flag `-f[no-]canonical-system-headers` to
match gcc in the future and further limit when it's passed by default.

Fixes #70011.

1 files changed, 7 insertions, 25 deletions

diff --git a/clang/lib/Frontend/DependencyFile.cpp b/clang/lib/Frontend/DependencyFile.cpp
index c2f6f41..19abcac 100644
--- a/clang/lib/Frontend/DependencyFile.cpp
+++ b/clang/lib/Frontend/DependencyFile.cpp
@@ -49,7 +49,6 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
       DepCollector.maybeAddDependency(
           llvm::sys::path::remove_leading_dotslash(*Filename),
           /*FromModule*/ false, isSystem(FileType), /*IsModuleFile*/ false,
-          &PP.getFileManager(),
           /*IsMissing*/ false);
   }
 
@@ -57,11 +56,9 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
                    SrcMgr::CharacteristicKind FileType) override {
     StringRef Filename =
         llvm::sys::path::remove_leading_dotslash(SkippedFile.getName());
-    DepCollector.maybeAddDependency(Filename,
-                                    /*FromModule=*/false,
+    DepCollector.maybeAddDependency(Filename, /*FromModule=*/false,
                                     /*IsSystem=*/isSystem(FileType),
                                     /*IsModuleFile=*/false,
-                                    &PP.getFileManager(),
                                     /*IsMissing=*/false);
   }
 
@@ -72,11 +69,9 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
                           StringRef RelativePath, const Module *Imported,
                           SrcMgr::CharacteristicKind FileType) override {
     if (!File)
-      DepCollector.maybeAddDependency(FileName,
-                                      /*FromModule*/ false,
+      DepCollector.maybeAddDependency(FileName, /*FromModule*/ false,
                                       /*IsSystem*/ false,
                                       /*IsModuleFile*/ false,
-                                      &PP.getFileManager(),
                                       /*IsMissing*/ true);
     // Files that actually exist are handled by FileChanged.
   }
@@ -88,11 +83,9 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
       return;
     StringRef Filename =
         llvm::sys::path::remove_leading_dotslash(File->getName());
-    DepCollector.maybeAddDependency(Filename,
-                                    /*FromModule=*/false,
+    DepCollector.maybeAddDependency(Filename, /*FromModule=*/false,
                                     /*IsSystem=*/isSystem(FileType),
                                     /*IsModuleFile=*/false,
-                                    &PP.getFileManager(),
                                     /*IsMissing=*/false);
   }
 
@@ -108,11 +101,9 @@ struct DepCollectorMMCallbacks : public ModuleMapCallbacks {
   void moduleMapFileRead(SourceLocation Loc, FileEntryRef Entry,
                          bool IsSystem) override {
     StringRef Filename = Entry.getName();
-    DepCollector.maybeAddDependency(Filename,
-                                    /*FromModule*/ false,
+    DepCollector.maybeAddDependency(Filename, /*FromModule*/ false,
                                     /*IsSystem*/ IsSystem,
                                     /*IsModuleFile*/ false,
-                                    /*FileMgr*/ nullptr,
                                     /*IsMissing*/ false);
   }
 };
@@ -128,10 +119,8 @@ struct DepCollectorASTListener : public ASTReaderListener {
   }
   void visitModuleFile(StringRef Filename,
                        serialization::ModuleKind Kind) override {
-    DepCollector.maybeAddDependency(Filename,
-                                    /*FromModule*/ true,
+    DepCollector.maybeAddDependency(Filename, /*FromModule*/ true,
                                     /*IsSystem*/ false, /*IsModuleFile*/ true,
-                                    /*FileMgr*/ nullptr,
                                     /*IsMissing*/ false);
   }
   bool visitInputFile(StringRef Filename, bool IsSystem,
@@ -145,7 +134,7 @@ struct DepCollectorASTListener : public ASTReaderListener {
       Filename = FE->getName();
 
     DepCollector.maybeAddDependency(Filename, /*FromModule*/ true, IsSystem,
-                                    /*IsModuleFile*/ false, /*FileMgr*/ nullptr,
+                                    /*IsModuleFile*/ false,
                                     /*IsMissing*/ false);
     return true;
   }
@@ -155,15 +144,9 @@ struct DepCollectorASTListener : public ASTReaderListener {
 void DependencyCollector::maybeAddDependency(StringRef Filename,
                                              bool FromModule, bool IsSystem,
                                              bool IsModuleFile,
-                                             FileManager *FileMgr,
                                              bool IsMissing) {
-  if (sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing)) {
-    if (IsSystem && FileMgr && shouldCanonicalizeSystemDependencies()) {
-      if (auto F = FileMgr->getOptionalFileRef(Filename))
-        Filename = FileMgr->getCanonicalName(*F);
-    }
+  if (sawDependency(Filename, FromModule, IsSystem, IsModuleFile, IsMissing))
     addDependency(Filename);
-  }
 }
 
 bool DependencyCollector::addDependency(StringRef Filename) {
@@ -211,7 +194,6 @@ DependencyFileGenerator::DependencyFileGenerator(
     const DependencyOutputOptions &Opts)
     : OutputFile(Opts.OutputFile), Targets(Opts.Targets),
       IncludeSystemHeaders(Opts.IncludeSystemHeaders),
-      CanonicalSystemHeaders(Opts.CanonicalSystemHeaders),
       PhonyTarget(Opts.UsePhonyTargets),
       AddMissingHeaderDeps(Opts.AddMissingHeaderDeps), SeenMissingHeader(false),
       IncludeModuleFiles(Opts.IncludeModuleFiles),