[clang] serialize ORIGINAL_PCH_DIR relative to BaseDirectory

[rmaz]

Summary

This diff changes the serialization of the ORIGINAL_PCH_DIR
entry in module files to be serialized relative to the module's
BaseDirectory. This will allow for the module to be relocatable
across machines.

The path is restored relative to the module's BaseDirectory on
deserialization.

[rmaz]

fix for missing temp dir in test

[urnathan]

Looks good to me, but perhaps leave it a few days for others to comment (my familiarity with this code is low). I do know people want relocatable outputs though.

[rmaz]

In D124946#3500454, @urnathan wrote:

Looks good to me, but perhaps leave it a few days for others to comment (my familiarity with this code is low). I do know people want relocatable outputs though.

Are we good to go with this one too now?

[urnathan]

good to go, thanks!

clang/lib/Serialization/ASTReader.cpp

case ORIGINAL_FILE:
       break;
 
     case ORIGINAL_FILE_ID:
       F.OriginalSourceFileID = FileID::get(Record[0]);
       break;
 
     case ORIGINAL_PCH_DIR:
       F.OriginalDir = std::string(Blob);
+      ResolveImportedPath(F, F.OriginalDir);
       break;
 
     case MODULE_NAME:
       F.ModuleName = std::string(Blob);
       Diag(diag::remark_module_import)
           << F.ModuleName << F.FileName << (ImportedBy ? true : false)
           << (ImportedBy ? StringRef(ImportedBy->ModuleName) : StringRef());
       if (Listener)

clang/lib/Serialization/ASTWriter.cpp

#include "clang/Basic/Sanitizers.def"
   // Original PCH directory
   if (!OutputFile.empty() && OutputFile != "-") {
     auto Abbrev = std::make_shared<BitCodeAbbrev>();
     Abbrev->Add(BitCodeAbbrevOp(ORIGINAL_PCH_DIR));
     Abbrev->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob)); // File name
     unsigned AbbrevCode = Stream.EmitAbbrev(std::move(Abbrev));
 
     SmallString<128> OutputPath(OutputFile);
-
-    SM.getFileManager().makeAbsolutePath(OutputPath);
+    PreparePathForOutput(OutputPath);
     StringRef origDir = llvm::sys::path::parent_path(OutputPath);
 
     RecordData::value_type Record[] = {ORIGINAL_PCH_DIR};
     Stream.EmitRecordWithBlob(AbbrevCode, Record, origDir);
   }
 
   std::set<const FileEntry *> AffectingModuleMaps;
   if (WritingModule) {

clang/test/Modules/relative-original-dir.m

+// RUN: rm -rf %t/normal-module-map
+// RUN: mkdir -p %t
+// RUN: cp -r %S/Inputs/normal-module-map %t
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -fmodule-name=libA -emit-module %t/normal-module-map/module.map -o %t/normal-module-map/outdir/mod.pcm
+// RUN: llvm-bcanalyzer --dump --disable-histogram %t/normal-module-map/outdir/mod.pcm | FileCheck %s
+
+// CHECK: <ORIGINAL_PCH_DIR abbrevid=7/> blob data = 'outdir'